WorldWideScience

Sample records for meso-scale controlled motion

  1. Improved analysis and visualization of friction loop data: unraveling the energy dissipation of meso-scale stick-slip motion

    Science.gov (United States)

    Kokorian, Jaap; Merlijn van Spengen, W.

    2017-11-01

    In this paper we demonstrate a new method for analyzing and visualizing friction force measurements of meso-scale stick-slip motion, and introduce a method for extracting two separate dissipative energy components. Using a microelectromechanical system tribometer, we execute 2 million reciprocating sliding cycles, during which we measure the static friction force with a resolution of \

  2. Optogenetic stimulation of a meso-scale human cortical model

    Science.gov (United States)

    Selvaraj, Prashanth; Szeri, Andrew; Sleigh, Jamie; Kirsch, Heidi

    2015-03-01

    Neurological phenomena like sleep and seizures depend not only on the activity of individual neurons, but on the dynamics of neuron populations as well. Meso-scale models of cortical activity provide a means to study neural dynamics at the level of neuron populations. Additionally, they offer a safe and economical way to test the effects and efficacy of stimulation techniques on the dynamics of the cortex. Here, we use a physiologically relevant meso-scale model of the cortex to study the hypersynchronous activity of neuron populations during epileptic seizures. The model consists of a set of stochastic, highly non-linear partial differential equations. Next, we use optogenetic stimulation to control seizures in a hyperexcited cortex, and to induce seizures in a normally functioning cortex. The high spatial and temporal resolution this method offers makes a strong case for the use of optogenetics in treating meso scale cortical disorders such as epileptic seizures. We use bifurcation analysis to investigate the effect of optogenetic stimulation in the meso scale model, and its efficacy in suppressing the non-linear dynamics of seizures.

  3. Development of a Meso-Scale Fiberoptic Rotation Sensor for a Torsion Actuator.

    Science.gov (United States)

    Sheng, Jun; Desai, Jaydev P

    2018-01-01

    This paper presents the development of a meso-scale fiberoptic rotation sensor for a shape memory alloy (SMA) torsion actuator for neurosurgical applications. Within the sensor, a rotary head with a reflecting surface is capable of modulating the light intensity collected by optical fibers when the rotary head is coupled to the torsion actuator. The mechanism of light intensity modulation is modeled, followed by experimental model verification. Meanwhile, working performances for different rotary head designs, optical fibers, and fabrication materials are compared. After the calibration of the fiberoptic rotation sensor, the sensor is capable of precisely measuring rotary motion and controlling the SMA torsion actuator with feedback control.

  4. MICRO-SEISMOMETERS VIA ADVANCED MESO-SCALE FABRICATION

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Caesar A; Onaran, Guclu; Avenson, Brad; Hall, Neal

    2014-11-07

    The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) seek revolutionary sensing innovations for the monitoring of nuclear detonations. Performance specifications are to be consistent with those obtainable by only an elite few products available today, but with orders of magnitude reduction in size, weight, power, and cost. The proposed commercial innovation calls upon several technologies including the combination of meso-scale fabrication and assembly, photonics-based displacement / motion detection methods, and the use of digital control electronics . Early Phase II development has demonstrated verified and repeatable sub 2ng noise floor from 3Hz to 100Hz, compact integration of 3-axis prototypes, and robust deployment exercises. Ongoing developments are focusing on low frequency challenges, low power consumption, ultra-miniature size, and low cross axis sensitivity. We are also addressing the rigorous set of specifications required for repeatable and reliable long-term explosion monitoring, including thermal stability, reduced recovery time from mass re-centering and large mechanical shocks, sensitivity stability, and transportability. Successful implementation will result in small, hand-held demonstration units with the ability to address national security needs of the DOE/NNSA. Additional applications envisioned include military/defense, scientific instrumentation, oil and gas exploration, inertial navigation, and civil infrastructure monitoring.

  5. Meso-scale wind variability. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, S.; Larsen, X.; Vincent, C.; Soerensen, P.; Pinson, P.; Trombe, P.-J.; Madsen, H.; Cutululis, N.

    2011-11-15

    The project has aimed to characterize mesoscale meteorological phenomenon for the North Sea and the Inner Danish waters, and additionally aimed on improving the predictability and quality of the power production from offshore windfarms. The meso-scale meteorology has been characterized with respect to the physical processes, climatology, spectral characteristics and correlation properties based on measurements from wind farms, satellite data (SAR) and mesoscale numerical modeling (WRF). The abilities of the WRF model to characterize and predict relevant mesoscale phenomenon has been proven. Additionally application of statistical forecasting, using a Markov switching approach that can be related to the meteorological conditions, to analyze and short term predict the power production from an offshore wind farms have been documented. Two PhD studies have been conducted in connection with the project. The project has been a cooperative project between Risoe DTU, IMM DTU, DONG Energy, Vattenfall and VESTAS. It is registered as Energinet.dk, project no. 2007-1-7141. (Author)

  6. Probabilistic, meso-scale flood loss modelling

    Science.gov (United States)

    Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

    2016-04-01

    Flood risk analyses are an important basis for decisions on flood risk management and adaptation. However, such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments and even more for flood loss modelling. State of the art in flood loss modelling is still the use of simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood loss models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we demonstrate and evaluate the upscaling of the approach to the meso-scale, namely on the basis of land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany (Botto et al. submitted). The application of bagging decision tree based loss models provide a probability distribution of estimated loss per municipality. Validation is undertaken on the one hand via a comparison with eight deterministic loss models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official loss data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of loss estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation approach is that it inherently provides quantitative information about the uncertainty of the prediction. References: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64. Botto A, Kreibich H, Merz B, Schröter K (submitted) Probabilistic, multi-variable flood loss modelling on the meso-scale with BT-FLEMO. Risk Analysis.

  7. A three-dimensional meso-scale modeling for helium bubble growth in metals

    International Nuclear Information System (INIS)

    Suzudo, T.; Kaburaki, H.; Wakai, E.

    2007-01-01

    A three-dimensional meso-scale computer model using a Monte-Carlo simulation method has been proposed to simulate the helium bubble growth in metals. The primary merit of this model is that it enables the visual comparison between the microstructure observed by the TEM imaging and those by calculations. The modeling is so simple that one can control easily the calculation by tuning parameters. The simulation results are confirmed by the ideal gas law and the capillary relation. helium bubble growth, meso-scale modeling, Monte-Carlo simulation, the ideal gas law and the capillary relation. (authors)

  8. Unifying Inference of Meso-Scale Structures in Networks.

    Science.gov (United States)

    Tunç, Birkan; Verma, Ragini

    2015-01-01

    Networks are among the most prevalent formal representations in scientific studies, employed to depict interactions between objects such as molecules, neuronal clusters, or social groups. Studies performed at meso-scale that involve grouping of objects based on their distinctive interaction patterns form one of the main lines of investigation in network science. In a social network, for instance, meso-scale structures can correspond to isolated social groupings or groups of individuals that serve as a communication core. Currently, the research on different meso-scale structures such as community and core-periphery structures has been conducted via independent approaches, which precludes the possibility of an algorithmic design that can handle multiple meso-scale structures and deciding which structure explains the observed data better. In this study, we propose a unified formulation for the algorithmic detection and analysis of different meso-scale structures. This facilitates the investigation of hybrid structures that capture the interplay between multiple meso-scale structures and statistical comparison of competing structures, all of which have been hitherto unavailable. We demonstrate the applicability of the methodology in analyzing the human brain network, by determining the dominant organizational structure (communities) of the brain, as well as its auxiliary characteristics (core-periphery).

  9. Unifying Inference of Meso-Scale Structures in Networks.

    Directory of Open Access Journals (Sweden)

    Birkan Tunç

    Full Text Available Networks are among the most prevalent formal representations in scientific studies, employed to depict interactions between objects such as molecules, neuronal clusters, or social groups. Studies performed at meso-scale that involve grouping of objects based on their distinctive interaction patterns form one of the main lines of investigation in network science. In a social network, for instance, meso-scale structures can correspond to isolated social groupings or groups of individuals that serve as a communication core. Currently, the research on different meso-scale structures such as community and core-periphery structures has been conducted via independent approaches, which precludes the possibility of an algorithmic design that can handle multiple meso-scale structures and deciding which structure explains the observed data better. In this study, we propose a unified formulation for the algorithmic detection and analysis of different meso-scale structures. This facilitates the investigation of hybrid structures that capture the interplay between multiple meso-scale structures and statistical comparison of competing structures, all of which have been hitherto unavailable. We demonstrate the applicability of the methodology in analyzing the human brain network, by determining the dominant organizational structure (communities of the brain, as well as its auxiliary characteristics (core-periphery.

  10. Flame dynamics of a meso-scale heat recirculating combustor

    Energy Technology Data Exchange (ETDEWEB)

    Vijayan, V.; Gupta, A.K. [Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States)

    2010-12-15

    The dynamics of premixed propane-air flame in a meso-scale ceramic combustor has been examined here. The flame characteristics in the combustor were examined by measuring the acoustic emissions and preheat temperatures together with high-speed cinematography. For the small-scale combustor, the volume to surface area ratio is small and hence the walls have significant effect on the global flame structure, flame location and flame dynamics. In addition to the flame-wall thermal coupling there is a coupling between flame and acoustics in the case of confined flames. Flame-wall thermal interactions lead to low frequency flame fluctuations ({proportional_to}100 Hz) depending upon the thermal response of the wall. However, the flame-acoustic interactions can result in a wide range of flame fluctuations ranging from few hundred Hz to few kHz. Wall temperature distribution is one of the factors that control the amount of reactant preheating which in turn effects the location of flame stabilization. Acoustic emission signals and high-speed flame imaging confirmed that for the present case flame-acoustic interactions have more significant effect on flame dynamics. Based on the acoustic emissions, five different flame regimes have been identified; whistling/harmonic mode, rich instability mode, lean instability mode, silent mode and pulsating flame mode. (author)

  11. Onset of meso-scale turbulence in active nematics

    NARCIS (Netherlands)

    Doostmohammadi, A.; Shendruk, T.N.; Thijssen, K.; Yeomans, J.M.

    2017-01-01

    Meso-scale turbulence is an innate phenomenon, distinct from inertial turbulence, that spontaneously occurs at low Reynolds number in fluidized biological systems. This spatiotemporal disordered flow radically changes nutrient and molecular transport in living fluids and can strongly affect the

  12. Micro- and meso-scale effects of forested terrain

    DEFF Research Database (Denmark)

    Dellwik, Ebba; Mann, Jakob; Sogachev, Andrey

    2011-01-01

    scales are the height of the planetary boundary layer and the Monin-Obukhov length, which both are related to the energy balance of the surface. Examples of important micro- and meso-scale effects of forested terrain are shown using data and model results from recent and ongoing experiments. For micro......The height and rotor diameter of modern wind turbines are so extensive, that the wind conditions they encounter often are well above the surface layer, where traditionally it is assumed that wind direction and turbulent fluxes are constant with respect to height, if the surface is homogenous....... Deviations from the requirement of homogeneity are often the focus of micro-scale studies in forested areas. Yet, to explain the wind climate in the relevant height range for turbines, it is necessary to also account for the length scales that are important parameters for the meso-scale flow. These length...

  13. Motion control report

    CERN Document Server

    2013-01-01

    Please note this is a short discount publication. In today's manufacturing environment, Motion Control plays a major role in virtually every project.The Motion Control Report provides a comprehensive overview of the technology of Motion Control:* Design Considerations* Technologies* Methods to Control Motion* Examples of Motion Control in Systems* A Detailed Vendors List

  14. LBM estimation of thermal conductivity in meso-scale modelling

    International Nuclear Information System (INIS)

    Grucelski, A

    2016-01-01

    Recently, there is a growing engineering interest in more rigorous prediction of effective transport coefficients for multicomponent, geometrically complex materials. We present main assumptions and constituents of the meso-scale model for the simulation of the coal or biomass devolatilisation with the Lattice Boltzmann method. For the results, the estimated values of the thermal conductivity coefficient of coal (solids), pyrolytic gases and air matrix are presented for a non-steady state with account for chemical reactions in fluid flow and heat transfer. (paper)

  15. Experimental Study on Meso-Scale Milling Process Using Nanofluid Minimum Quantity Lubrication

    International Nuclear Information System (INIS)

    Lee, P. H.; Nam, T. S.; Li, Cheng Jun; Lee, S. W.

    2010-01-01

    This paper present the characteristics of micro- and meso-scale milling processes in which compressed cold air, minimum quantity lubrication (MQL) and MoS 2 nanofluid MQL are used. For process characterization, the micro and meso-scale milling experiments are conducted using desktop meso-scale machine tool system and the surface roughness is measured. The experimental results show that the use of compressed chilly air and nanofluid MQL in the micro- and meso-scale milling processes is effective in improving the surface finish

  16. Green's Kernels and meso-scale approximations in perforated domains

    CERN Document Server

    Maz'ya, Vladimir; Nieves, Michael

    2013-01-01

    There are a wide range of applications in physics and structural mechanics involving domains with singular perturbations of the boundary. Examples include perforated domains and bodies with defects of different types. The accurate direct numerical treatment of such problems remains a challenge. Asymptotic approximations offer an alternative, efficient solution. Green’s function is considered here as the main object of study rather than a tool for generating solutions of specific boundary value problems. The uniformity of the asymptotic approximations is the principal point of attention. We also show substantial links between Green’s functions and solutions of boundary value problems for meso-scale structures. Such systems involve a large number of small inclusions, so that a small parameter, the relative size of an inclusion, may compete with a large parameter, represented as an overall number of inclusions. The main focus of the present text is on two topics: (a) asymptotics of Green’s kernels in domai...

  17. Implementation of meso-scale radioactive dispersion model for GPU

    Energy Technology Data Exchange (ETDEWEB)

    Sunarko [National Nuclear Energy Agency of Indonesia (BATAN), Jakarta (Indonesia). Nuclear Energy Assessment Center; Suud, Zaki [Bandung Institute of Technology (ITB), Bandung (Indonesia). Physics Dept.

    2017-05-15

    Lagrangian Particle Dispersion Method (LPDM) is applied to model atmospheric dispersion of radioactive material in a meso-scale of a few tens of kilometers for site study purpose. Empirical relationships are used to determine the dispersion coefficient for various atmospheric stabilities. Diagnostic 3-D wind-field is solved based on data from one meteorological station using mass-conservation principle. Particles representing radioactive pollutant are dispersed in the wind-field as a point source. Time-integrated air concentration is calculated using kernel density estimator (KDE) in the lowest layer of the atmosphere. Parallel code is developed for GTX-660Ti GPU with a total of 1 344 scalar processors using CUDA. A test of 1-hour release discovers that linear speedup is achieved starting at 28 800 particles-per-hour (pph) up to about 20 x at 14 4000 pph. Another test simulating 6-hour release with 36 000 pph resulted in a speedup of about 60 x. Statistical analysis reveals that resulting grid doses are nearly identical in both CPU and GPU versions of the code.

  18. Probabilistic flood damage modelling at the meso-scale

    Science.gov (United States)

    Kreibich, Heidi; Botto, Anna; Schröter, Kai; Merz, Bruno

    2014-05-01

    Decisions on flood risk management and adaptation are usually based on risk analyses. Such analyses are associated with significant uncertainty, even more if changes in risk due to global change are expected. Although uncertainty analysis and probabilistic approaches have received increased attention during the last years, they are still not standard practice for flood risk assessments. Most damage models have in common that complex damaging processes are described by simple, deterministic approaches like stage-damage functions. Novel probabilistic, multi-variate flood damage models have been developed and validated on the micro-scale using a data-mining approach, namely bagging decision trees (Merz et al. 2013). In this presentation we show how the model BT-FLEMO (Bagging decision Tree based Flood Loss Estimation MOdel) can be applied on the meso-scale, namely on the basis of ATKIS land-use units. The model is applied in 19 municipalities which were affected during the 2002 flood by the River Mulde in Saxony, Germany. The application of BT-FLEMO provides a probability distribution of estimated damage to residential buildings per municipality. Validation is undertaken on the one hand via a comparison with eight other damage models including stage-damage functions as well as multi-variate models. On the other hand the results are compared with official damage data provided by the Saxon Relief Bank (SAB). The results show, that uncertainties of damage estimation remain high. Thus, the significant advantage of this probabilistic flood loss estimation model BT-FLEMO is that it inherently provides quantitative information about the uncertainty of the prediction. Reference: Merz, B.; Kreibich, H.; Lall, U. (2013): Multi-variate flood damage assessment: a tree-based data-mining approach. NHESS, 13(1), 53-64.

  19. Meso-scale modeling of irradiated concrete in test reactor

    International Nuclear Information System (INIS)

    Giorla, A.; Vaitová, M.; Le Pape, Y.; Štemberk, P.

    2015-01-01

    Highlights: • A meso-scale finite element model for irradiated concrete is developed. • Neutron radiation-induced volumetric expansion is a predominant degradation mode. • Confrontation with expansion and damage obtained from experiments is successful. • Effects of paste shrinkage, creep and ductility are discussed. - Abstract: A numerical model accounting for the effects of neutron irradiation on concrete at the mesoscale is detailed in this paper. Irradiation experiments in test reactor (Elleuch et al., 1972), i.e., in accelerated conditions, are simulated. Concrete is considered as a two-phase material made of elastic inclusions (aggregate) subjected to thermal and irradiation-induced swelling and embedded in a cementitious matrix subjected to shrinkage and thermal expansion. The role of the hardened cement paste in the post-peak regime (brittle-ductile transition with decreasing loading rate), and creep effects are investigated. Radiation-induced volumetric expansion (RIVE) of the aggregate cause the development and propagation of damage around the aggregate which further develops in bridging cracks across the hardened cement paste between the individual aggregate particles. The development of damage is aggravated when shrinkage occurs simultaneously with RIVE during the irradiation experiment. The post-irradiation expansion derived from the simulation is well correlated with the experimental data and, the obtained damage levels are fully consistent with previous estimations based on a micromechanical interpretation of the experimental post-irradiation elastic properties (Le Pape et al., 2015). The proposed modeling opens new perspectives for the interpretation of test reactor experiments in regards to the actual operation of light water reactors.

  20. Meso-scale modeling of irradiated concrete in test reactor

    Energy Technology Data Exchange (ETDEWEB)

    Giorla, A. [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Vaitová, M. [Czech Technical University, Thakurova 7, 166 29 Praha 6 (Czech Republic); Le Pape, Y., E-mail: lepapeym@ornl.gov [Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831 (United States); Štemberk, P. [Czech Technical University, Thakurova 7, 166 29 Praha 6 (Czech Republic)

    2015-12-15

    Highlights: • A meso-scale finite element model for irradiated concrete is developed. • Neutron radiation-induced volumetric expansion is a predominant degradation mode. • Confrontation with expansion and damage obtained from experiments is successful. • Effects of paste shrinkage, creep and ductility are discussed. - Abstract: A numerical model accounting for the effects of neutron irradiation on concrete at the mesoscale is detailed in this paper. Irradiation experiments in test reactor (Elleuch et al., 1972), i.e., in accelerated conditions, are simulated. Concrete is considered as a two-phase material made of elastic inclusions (aggregate) subjected to thermal and irradiation-induced swelling and embedded in a cementitious matrix subjected to shrinkage and thermal expansion. The role of the hardened cement paste in the post-peak regime (brittle-ductile transition with decreasing loading rate), and creep effects are investigated. Radiation-induced volumetric expansion (RIVE) of the aggregate cause the development and propagation of damage around the aggregate which further develops in bridging cracks across the hardened cement paste between the individual aggregate particles. The development of damage is aggravated when shrinkage occurs simultaneously with RIVE during the irradiation experiment. The post-irradiation expansion derived from the simulation is well correlated with the experimental data and, the obtained damage levels are fully consistent with previous estimations based on a micromechanical interpretation of the experimental post-irradiation elastic properties (Le Pape et al., 2015). The proposed modeling opens new perspectives for the interpretation of test reactor experiments in regards to the actual operation of light water reactors.

  1. Diatoms as a fingerprint of sub-catchment contributions to meso-scale catchment runoff

    Science.gov (United States)

    Klaus, Julian; Wetzel, Carlos E.; Martinez-Carreras, Nuria; Ector, Luc; Pfister, Laurent

    2014-05-01

    In recent years, calls were made for new eco-hydrological approaches to improve understanding of hydrological processes. Recently diatoms, one of the most common and diverse algal groups that can be easily transported by flowing water due to their small size (~10-200 µm), were used to detect the onset and cessation of surface runoff to small headwater streams and constrain isotopic and hydro-chemical hydrograph separation methods. While the method showed its potential in the hillslope-riparian zone-stream continuum of headwater catchments, the behavior of diatoms and their use for hydrological process research in meso-scale catchments remains uncertain. Diatoms can be a valuable support for isotope and hydro-chemical tracer methods when these become ambiguous with increasing scale. Distribution and abundance of diatom species is controlled by various environmental factors (pH, soil type, moisture conditions, exposition to sunlight, etc.). We therefore hypothesize that species abundance and composition can be used as a proxy for source areas. This presentation evaluates the potential for diatoms to trace source-areas in the nested meso-scale Attert River basin (250 km2, Luxembourg, Europe). We sampled diatom populations in streamwater during one flood event in Fall 2011 in 6 sub-catchments and the basin outlet - 17 to 28 samples/catchment for the different sampling locations. Diatoms were classified and counted in every individual sample. In total more than 400 diatom species were detected. Ordination analysis revealed a clear distinction between communities sampled in different sub-catchments. The species composition at the catchment outlet reflects a mixing of the diatom composition originating from different sub-catchments. This data suggests that diatoms indeed can reflect the geographic origin of stream water at the catchment outlet. The centroids of the ordination analysis might be linked to the physiographic characteristics (geology and land use) of the

  2. Ship Roll Motion Control

    DEFF Research Database (Denmark)

    Perez, Tristan; Blanke, Mogens

    2010-01-01

    . This tutorial paper presents an account of the development of various ship roll motion control systems and the challenges associated with their design. The paper discusses how to assess performance, the applicability of dierent models, and control methods that have been applied in the past....

  3. An interview with James Wilbur, Ph.D. General Manager, Life Sciences, Meso Scale Discovery.

    Science.gov (United States)

    Wilbur, James

    2004-06-01

    James L. Wilbur, Ph.D. received a Bachelor's degree from the University of California, San Diego and a Ph.D. in Chemistry from Stanford University. After completing an NIH Postdoctoral Fellowship with Professor George M. Whitesides in the Department of Chemistry at Harvard University, he joined IGEN International, Inc., where he held a variety of positions in Research and Development. During that time, he was part of the team that developed the core technology and products for Meso Scale Discovery. He assumed his current position in 2001 when Meso Scale Discovery launched the products discussed here.

  4. Motion Control with Vision

    NARCIS (Netherlands)

    Ir. Dick van Schenk Brill; Ir Peter Boots

    2001-01-01

    This paper describes the work that is done by a group of I3 students at Philips CFT in Eindhoven, Netherlands. I3 is an initiative of Fontys University of Professional Education also located in Eindhoven. The work focuses on the use of computer vision in motion control. Experiments are done with

  5. The plastic rotation effect in an isotropic gradient plasticity model for applications at the meso scale

    NARCIS (Netherlands)

    Poh, Leong Hien; Peerlings, R.H.J.

    2016-01-01

    Although formulated to represent a large system of polycrystals at the macroscopic level, isotropic gradient plasticity models have routinely been adopted at the meso scale. For such purposes, it is crucial to incorporate the plastic rotation effect in order to obtain a reasonable approximation of

  6. Motion sensing energy controller

    International Nuclear Information System (INIS)

    Saphir, M.E.; Reed, M.A.

    1984-01-01

    A moving object sensing processor responsive to slowly varying motions of a human being or other moving object in a zone of interest employs high frequency pulse modulated non-visible radiation generated by a radiation generating source, such as an LED, and detected by a detector sensitive to radiation of a preselected wavelength which generates electrical signals representative of the reflected radiation received from the zone of interest. The detectorsignals are processed to normalize the base level and remove variations due to background level changes, and slowly varying changes in the signals are detected by a bi-polar threshold detector. The control signals generated by the threshold detector in response to slowly varying motion are used to control the application of power to a utilization device, such as a set of fluoroescent lights in a room, the power being applied in response to detection of such motion and being automatically terminated in the absence of such motion after a predetermined time period established by a settable incrementable counter

  7. Compression instrument for tissue experiments (cite) at the meso-scale: device validation - biomed 2011.

    Science.gov (United States)

    Evans, Douglas W; Rajagopalan, Padma; Devita, Raffaella; Sparks, Jessica L

    2011-01-01

    Liver sinusoidal endothelial cells (LSECs) are the primary site of numerous transport and exchange processes essential for liver function. LSECs rest on a sparse extracellular matrix layer housed in the space of Disse, a 0.5-1LSECs from hepatocytes. To develop bioengineered liver tissue constructs, it is important to understand the mechanical interactions among LSECs, hepatocytes, and the extracellular matrix in the space of Disse. Currently the mechanical properties of space of Disse matrix are not well understood. The objective of this study was to develop and validate a device for performing mechanical tests at the meso-scale (100nm-100m), to enable novel matrix characterization within the space of Disse. The device utilizes a glass micro-spherical indentor attached to a cantilever made from a fiber optic cable. The 3-axis translation table used to bring the specimen in contact with the indentor and deform the cantilever. A position detector monitors the location of a laser passing through the cantilever and allows for the calculation of subsequent tissue deformation. The design allows micro-newton and nano-newton stress-strain tissue behavior to be quantified. To validate the device accuracy, 11 samples of silicon rubber in two formulations were tested to experimentally confirm their Young's moduli. Prior macroscopic unconfined compression tests determined the formulations of EcoFlex030 (n-6) and EcoFlex010 (n-5) to posses Young's moduli of 92.67+-6.22 and 43.10+-3.29 kPa respectively. Optical measurements taken utilizing CITE's position control and fiber optic cantilever found the moduli to be 106.4 kPa and 47.82 kPa.

  8. Coastal Foredune Evolution, Part 2: Modeling Approaches for Meso-Scale Morphologic Evolution

    Science.gov (United States)

    2017-03-01

    for Meso-Scale Morphologic Evolution by Margaret L. Palmsten1, Katherine L. Brodie2, and Nicholas J. Spore2 PURPOSE: This Coastal and Hydraulics ...managers because foredunes provide ecosystem services and can reduce storm damages to coastal infrastructure, both of which increase the resiliency...MS 2 U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, Duck, NC ERDC/CHL CHETN-II-57 March 2017 2 models of

  9. Meso-scale effects of tropical deforestation in Amazonia: preparatory LBA modelling studies

    Directory of Open Access Journals (Sweden)

    A. J. Dolman

    1999-08-01

    Full Text Available As part of the preparation for the Large-Scale Biosphere Atmosphere Experiment in Amazonia, a meso-scale modelling study was executed to highlight deficiencies in the current understanding of land surface atmosphere interaction at local to sub-continental scales in the dry season. Meso-scale models were run in 1-D and 3-D mode for the area of Rondonia State, Brazil. The important conclusions are that without calibration it is difficult to model the energy partitioning of pasture; modelling that of forest is easier due to the absence of a strong moisture deficit signal. The simulation of the boundary layer above forest is good, above deforested areas (pasture poor. The models' underestimate of the temperature of the boundary layer is likely to be caused by the neglect of the radiative effects of aerosols caused by biomass burning, but other factors such as lack of sufficient entrainment in the model at the mixed layer top may also contribute. The Andes generate patterns of subsidence and gravity waves, the effects of which are felt far into the Rondonian area The results show that the picture presented by GCM modelling studies may need to be balanced by an increased understanding of what happens at the meso-scale. The results are used to identify key measurements for the LBA atmospheric meso-scale campaign needed to improve the model simulations. Similar modelling studies are proposed for the wet season in Rondonia, when convection plays a major role.Key words. Atmospheric composition and structure (aerosols and particles; biosphere-atmosphere interactions · Meterology and atmospheric dynamics (mesoscale meterology

  10. Meso-scale effects of tropical deforestation in Amazonia: preparatory LBA modelling studies

    Directory of Open Access Journals (Sweden)

    A. J. Dolman

    Full Text Available As part of the preparation for the Large-Scale Biosphere Atmosphere Experiment in Amazonia, a meso-scale modelling study was executed to highlight deficiencies in the current understanding of land surface atmosphere interaction at local to sub-continental scales in the dry season. Meso-scale models were run in 1-D and 3-D mode for the area of Rondonia State, Brazil. The important conclusions are that without calibration it is difficult to model the energy partitioning of pasture; modelling that of forest is easier due to the absence of a strong moisture deficit signal. The simulation of the boundary layer above forest is good, above deforested areas (pasture poor. The models' underestimate of the temperature of the boundary layer is likely to be caused by the neglect of the radiative effects of aerosols caused by biomass burning, but other factors such as lack of sufficient entrainment in the model at the mixed layer top may also contribute. The Andes generate patterns of subsidence and gravity waves, the effects of which are felt far into the Rondonian area The results show that the picture presented by GCM modelling studies may need to be balanced by an increased understanding of what happens at the meso-scale. The results are used to identify key measurements for the LBA atmospheric meso-scale campaign needed to improve the model simulations. Similar modelling studies are proposed for the wet season in Rondonia, when convection plays a major role.

    Key words. Atmospheric composition and structure (aerosols and particles; biosphere-atmosphere interactions · Meterology and atmospheric dynamics (mesoscale meterology

  11. A CFD Analysis of The Performance of Pin-Fin Laminar Flow Micro/Meso Scale Heat Exchangers

    National Research Council Canada - National Science Library

    Dimas, Sotirios

    2005-01-01

    A full three dimensional computational study was carried out using a finite-volume based solver for analyzing the performance of pin-fin based micro/meso scale heat exchangers with air as the working fluid...

  12. Evaluation of the performance of a meso-scale NWP model to forecast solar irradiance on Reunion Island for photovoltaic power applications

    Science.gov (United States)

    Kalecinski, Natacha; Haeffelin, Martial; Badosa, Jordi; Periard, Christophe

    2013-04-01

    Solar photovoltaic power is a predominant source of electrical power on Reunion Island, regularly providing near 30% of electrical power demand for a few hours per day. However solar power on Reunion Island is strongly modulated by clouds in small temporal and spatial scales. Today regional regulations require that new solar photovoltaic plants be combined with storage systems to reduce electrical power fluctuations on the grid. Hence cloud and solar irradiance forecasting becomes an important tool to help optimize the operation of new solar photovoltaic plants on Reunion Island. Reunion Island, located in the South West of the Indian Ocean, is exposed to persistent trade winds, most of all in winter. In summer, the southward motion of the ITCZ brings atmospheric instabilities on the island and weakens trade winds. This context together with the complex topography of Reunion Island, which is about 60 km wide, with two high summits (3070 and 2512 m) connected by a 1500 m plateau, makes cloudiness very heterogeneous. High cloudiness variability is found between mountain and coastal areas and between the windward, leeward and lateral regions defined with respect to the synoptic wind direction. A detailed study of local dynamics variability is necessary to better understand cloud life cycles around the island. In the presented work, our approach to explore the short-term solar irradiance forecast at local scales is to use the deterministic output from a meso-scale numerical weather prediction (NWP) model, AROME, developed by Meteo France. To start we evaluate the performance of the deterministic forecast from AROME by using meteorological measurements from 21 meteorological ground stations widely spread around the island (and with altitudes from 8 to 2245 m). Ground measurements include solar irradiation, wind speed and direction, relative humidity, air temperature, precipitation and pressure. Secondly we study in the model the local dynamics and thermodynamics that

  13. Characterizing the Meso-scale Plasma Flows in Earth's Coupled Magnetosphere-Ionosphere-Thermosphere System

    Science.gov (United States)

    Gabrielse, C.; Nishimura, T.; Lyons, L. R.; Gallardo-Lacourt, B.; Deng, Y.; McWilliams, K. A.; Ruohoniemi, J. M.

    2017-12-01

    NASA's Heliophysics Decadal Survey put forth several imperative, Key Science Goals. The second goal communicates the urgent need to "Determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs...over a range of spatial and temporal scales." Sun-Earth connections (called Space Weather) have strong societal impacts because extreme events can disturb radio communications and satellite operations. The field's current modeling capabilities of such Space Weather phenomena include large-scale, global responses of the Earth's upper atmosphere to various inputs from the Sun, but the meso-scale ( 50-500 km) structures that are much more dynamic and powerful in the coupled system remain uncharacterized. Their influences are thus far poorly understood. We aim to quantify such structures, particularly auroral flows and streamers, in order to create an empirical model of their size, location, speed, and orientation based on activity level (AL index), season, solar cycle (F10.7), interplanetary magnetic field (IMF) inputs, etc. We present a statistical study of meso-scale flow channels in the nightside auroral oval and polar cap using SuperDARN. These results are used to inform global models such as the Global Ionosphere Thermosphere Model (GITM) in order to evaluate the role of meso-scale disturbances on the fully coupled magnetosphere-ionosphere-thermosphere system. Measuring the ionospheric footpoint of magnetospheric fast flows, our analysis technique from the ground also provides a 2D picture of flows and their characteristics during different activity levels that spacecraft alone cannot.

  14. Resolving meso-scale seabed variability using reflection measurements from an autonomous underwater vehicle.

    Science.gov (United States)

    Holland, Charles W; Nielsen, Peter L; Dettmer, Jan; Dosso, Stan

    2012-02-01

    Seabed geoacoustic variability is driven by geological processes that occur over a wide spectrum of space-time scales. While the acoustics community has some understanding of horizontal fine-scale geoacoustic variability, less than O(10(0)) m, and large-scale variability, greater than O(10(3)) m, there is a paucity of data resolving the geoacoustic meso-scale O(10(0)-10(3)) m. Measurements of the meso-scale along an ostensibly "benign" portion of the outer shelf reveal three classes of variability. The first class was expected and is due to horizontal variability of layer thicknesses: this was the only class that could be directly tied to seismic reflection data. The second class is due to rapid changes in layer properties and/or boundaries, occurring over scales of meters to hundreds of meters. The third class was observed as rapid variations of the angle/frequency dependent reflection coefficient within a single observation and is suggestive of variability at scales of meter or less. Though generally assumed to be negligible in acoustic modeling, the second and third classes are indicative of strong horizontal geoacoustic variability within a given layer. The observations give early insight into possible effects of horizontal geoacoustic variability on long-range acoustic propagation and reverberation. © 2012 Acoustical Society of America

  15. Meso-scale wrinkled coatings to improve heat transfers of surfaces facing ambient air

    International Nuclear Information System (INIS)

    Kakiuchida, Hiroshi; Tajiri, Koji; Tazawa, Masato; Yoshimura, Kazuki; Shimono, Kazuaki; Nakagawa, Yukio; Takahashi, Kazuhiro; Fujita, Keisuke; Myoko, Masumi

    2015-01-01

    Meso-scale (micrometer-to submillimeter-scale) wrinkled surfaces coated on steel sheets used in outdoor storage and transport facilities for industrial low-temperature liquids were discovered to efficiently increase convective heat transfer between ambient air and the surface. The radiative and convective heat transfer coefficients of various wrinkled surfaces, which were formed by coating steel sheets with several types of shrinkable paints, were examined. The convective heat transfer coefficient of a surface colder than ambient air monotonically changed with average height difference and interval distance of the wrinkle undulation, where the proportions were 0.0254 and 0.0054 W/m 2 /K/μm, respectively. With this wrinkled coating, users can lower the possibility of condensation and reduce rust and maintenance cost of facilities for industrial low-temperature liquids. From the point of view of manufacturers, this coating method can be easily adapted to conventional manufacturing processes. - Highlights: • Various wrinkled surfaces were fabricated by a practical process. • Topographical effect on convection was parameterized separately from radiation. • Meso-scale wrinkled coatings increased convective heat transfer with ambient air. • Maintenance cost of outdoor steel sheets due to condensation can be reduced

  16. Dynamics of bluff-body-stabilized lean premixed syngas flames in a meso-scale channel

    KAUST Repository

    Lee, Bok Jik

    2016-07-15

    Direct numerical simulations are conducted to investigate the dynamics of lean premixed syngas flames stabilized by a bluff-body in a meso-scale channel at near blow-off conditions, in order to provide fundamental insights into the physical mechanisms responsible for the critical phenomena. Flames in a two-dimensional meso-scale channel with a square flame holder are adopted as the model configuration, and a syngas mixture at an equivalence ratio of 0.5 with the CO:H ratio of 1 is considered. As the inlet velocity is increased, the initially stable steady flames undergo a transition to an unsteady mode of regular asymmetric fluctuation. When the inlet velocity is further increased, the flame is eventually blown off. Between the regular fluctuation mode and blow-off limit, there exists a narrow range of the inlet velocity where the flames exhibit periodic local extinction and recovery. Approaching further to the blow-off limit, the recovery mode fails to occur but the flame survives as a short kernel attached to the base of the bluff-body, until it is completely extinguished as the attached flames are gradually shrunk towards the bluff-body. The results are systematically compared with the hydrogen flame results reported in our earlier study. Examination of the characteristic time scales of relevant processes provided understanding of key mechanisms responsible for the observed differences, thereby allowing improved description of the local extinction and re-ignition dynamics that are critical to flame stabilization.

  17. Robot Motion and Control 2011

    CERN Document Server

    2012-01-01

    Robot Motion Control 2011 presents very recent results in robot motion and control. Forty short papers have been chosen from those presented at the sixth International Workshop on Robot Motion and Control held in Poland in June 2011. The authors of these papers have been carefully selected and represent leading institutions in this field. The following recent developments are discussed: • Design of trajectory planning schemes for holonomic and nonholonomic systems with optimization of energy, torque limitations and other factors. • New control algorithms for industrial robots, nonholonomic systems and legged robots. • Different applications of robotic systems in industry and everyday life, like medicine, education, entertainment and others. • Multiagent systems consisting of mobile and flying robots with their applications The book is suitable for graduate students of automation and robotics, informatics and management, mechatronics, electronics and production engineering systems as well as scientists...

  18. Modelling daily sediment yield from a meso-scale catchment, a case study in SW Poland

    International Nuclear Information System (INIS)

    Keesstra, S. D.; Schoorl, J.; Temme, A. J. A. M.

    2009-01-01

    For management purposes it is important to be able to assess the sediment yield of a catchment. however, at this moment models designed for estimating sediment yield are only capable to give either very detailed storm-based information or year averages. The storm-based models require input data that are not available for most catchment. However, models that estimate yearly averages, ignore a lot of other detailed information, like daily discharge and precipitation data. There are currently no models available that model sediment yield on the temporal scale of one day and the spatial scale of a meso-scale catchment, without making use of very detailed input data. To fill this scientific and management gap, landscape evolution model LAPSUS has been adapted to model sediment yield on a daily basis. This model has the water balance as a base. To allow calibration with the discharge at the outlet, a subsurface flow module has been added to the model. (Author) 12 refs.

  19. Modelling daily sediment yield from a meso-scale catchment, a case study in SW Poland

    Energy Technology Data Exchange (ETDEWEB)

    Keesstra, S. D.; Schoorl, J.; Temme, A. J. A. M.

    2009-07-01

    For management purposes it is important to be able to assess the sediment yield of a catchment. however, at this moment models designed for estimating sediment yield are only capable to give either very detailed storm-based information or year averages. The storm-based models require input data that are not available for most catchment. However, models that estimate yearly averages, ignore a lot of other detailed information, like daily discharge and precipitation data. There are currently no models available that model sediment yield on the temporal scale of one day and the spatial scale of a meso-scale catchment, without making use of very detailed input data. To fill this scientific and management gap, landscape evolution model LAPSUS has been adapted to model sediment yield on a daily basis. This model has the water balance as a base. To allow calibration with the discharge at the outlet, a subsurface flow module has been added to the model. (Author) 12 refs.

  20. Meso-scale magnetic signatures for nuclear reactor steel irradiation embrittlement monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Suter, J. D., E-mail: pradeep.ramuhalli@pnnl.gov; Ramuhalli, P., E-mail: pradeep.ramuhalli@pnnl.gov; Hu, S.; Li, Y.; Jiang, W.; Edwards, D. J.; Schemer-Kohrn, A. L.; Johnson, B. R. [Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA 99352 (United States); McCloy, J. S., E-mail: john.mccloy@wsu.edu; Xu, K., E-mail: john.mccloy@wsu.edu [Washington State University, PO Box 642920, Pullman, WA 99164 (United States)

    2015-03-31

    Verifying the structural integrity of passive components in light water and advanced reactors will be necessary to ensure safe, long-term operations of the existing U.S. nuclear fleet. This objective can be achieved through nondestructive condition monitoring techniques, which can be integrated with plant operations to quantify the “state of health” of structural materials in real-time. While nondestructive methods for monitoring many classes of degradation (such as fatigue or stress corrosion cracking) are relatively advanced, this is not the case for degradation caused by irradiation. The development of nondestructive evaluation technologies for these types of degradation will require advanced materials characterization techniques and tools that enable comprehensive understanding of nuclear reactor material microstructural and behavioral changes under extreme operating environments. Irradiation-induced degradation of reactor steels causes changes in their microstructure that impacts their micro-magnetic properties. In this paper, we describe preliminary results of integrating advanced material characterization techniques with meso-scale computational models. In the future, this will help to provide an interpretive understanding of the state of degradation in structural materials. Microstructural data are presented from monocrystalline Fe and are correlated with variable-field magnetic force microscopy and micro-magnetic measurements. Ongoing research is focused on extending the measurements and models on thin films to gain insights into the structural state of irradiated materials and the resulting impact on magnetic properties. Preliminary conclusions from these correlations are presented, and next steps described.

  1. Development of an Efficient Meso- scale Multi-phase Flow Solver in Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taehun [City Univ. (CUNY), NY (United States)

    2015-10-20

    The proposed research aims at formulating a predictive high-order Lattice Boltzmann Equation for multi-phase flows relevant to nuclear energy related application - namely, saturated and sub-cooled boiling in reactors, and liquid- liquid mixing and extraction for fuel cycle separation. An efficient flow solver will be developed based on the Finite Element based Lattice Boltzmann Method (FE- LBM), accounting for phase-change heat transfer and capable of treating multiple phases over length scales from the submicron to the meter. A thermal LBM will be developed in order to handle adjustable Prandtl number, arbitrary specific heat ratio, a wide range of temperature variations, better numerical stability during liquid-vapor phase change, and full thermo-hydrodynamic consistency. Two-phase FE-LBM will be extended to liquid–liquid–gas multi-phase flows for application to high-fidelity simulations building up from the meso-scale up to the equipment sub-component scale. While several relevant applications exist, the initial applications for demonstration of the efficient methods to be developed as part of this project include numerical investigations of Critical Heat Flux (CHF) phenomena in nuclear reactor fuel bundles, and liquid-liquid mixing and interfacial area generation for liquid-liquid separations. In addition, targeted experiments will be conducted for validation of this advanced multi-phase model.

  2. Wheelchair control by head motion

    Directory of Open Access Journals (Sweden)

    Pajkanović Aleksandar

    2013-01-01

    Full Text Available Electric wheelchairs are designed to aid paraplegics. Unfortunately, these can not be used by persons with higher degree of impairment, such as quadriplegics, i.e. persons that, due to age or illness, can not move any of the body parts, except of the head. Medical devices designed to help them are very complicated, rare and expensive. In this paper a microcontroller system that enables standard electric wheelchair control by head motion is presented. The system comprises electronic and mechanic components. A novel head motion recognition technique based on accelerometer data processing is designed. The wheelchair joystick is controlled by the system’s mechanical actuator. The system can be used with several different types of standard electric wheelchairs. It is tested and verified through an experiment performed within this paper.

  3. Image-based correlation between the meso-scale structure and deformation of closed-cell foam

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yongle, E-mail: yongle.sun@manchester.ac.uk [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Sackville Street, Manchester M13 9PL (United Kingdom); Zhang, Xun [Henry Moseley X-ray Imaging Facility, School of Materials, The University of Manchester, Upper Brook Street, Manchester M13 9PL (United Kingdom); Shao, Zhushan [School of Civil Engineering, Xi' an University of Architecture & Technology, Xi' an 710055 (China); Li, Q.M. [School of Mechanical, Aerospace and Civil Engineering, The University of Manchester, Sackville Street, Manchester M13 9PL (United Kingdom); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

    2017-03-14

    In the correlation between structural parameters and compressive behaviour of cellular materials, previous studies have mostly focused on averaged structural parameters and bulk material properties for different samples. This study focuses on the meso-scale correlation between structure and deformation in a 2D foam sample generated from a computed tomography slice of Alporas™ foam, for which quasi-static compression was simulated using 2D image-based finite element modelling. First, a comprehensive meso-scale structural characterisation of the 2D foam was carried out to determine the size, aspect ratio, orientation and anisotropy of individual cells, as well as the length, straightness, inclination and thickness of individual cell walls. Measurements were then conducted to obtain the axial distributions of local structural parameters averaged laterally to compression axis. Second, the meso-scale deformation was characterised by cell-wall strain, cell area ratio, digital image correlation strain and local compressive engineering strain. According to the results, the through-width sub-regions over an axial length between the average (lower bound) and the maximum (upper bound) of cell size should be used to characterise the meso-scale heterogeneity of the cell structure and deformation. It was found that the first crush band forms in a sub-region where the ratio of cell-wall thickness to cell-wall length is a minimum, in which the collapse deformation is dominated by the plastic bending and buckling of cell walls. Other morphological parameters have secondary effect on the initiation of crush band in the 2D foam. The finding of this study suggests that the measurement of local structural properties is crucial for the identification of the “weakest” region which determines the initiation of collapse and hence the corresponding collapse load of a heterogeneous cellular material.

  4. Image-based correlation between the meso-scale structure and deformation of closed-cell foam

    International Nuclear Information System (INIS)

    Sun, Yongle; Zhang, Xun; Shao, Zhushan; Li, Q.M.

    2017-01-01

    In the correlation between structural parameters and compressive behaviour of cellular materials, previous studies have mostly focused on averaged structural parameters and bulk material properties for different samples. This study focuses on the meso-scale correlation between structure and deformation in a 2D foam sample generated from a computed tomography slice of Alporas™ foam, for which quasi-static compression was simulated using 2D image-based finite element modelling. First, a comprehensive meso-scale structural characterisation of the 2D foam was carried out to determine the size, aspect ratio, orientation and anisotropy of individual cells, as well as the length, straightness, inclination and thickness of individual cell walls. Measurements were then conducted to obtain the axial distributions of local structural parameters averaged laterally to compression axis. Second, the meso-scale deformation was characterised by cell-wall strain, cell area ratio, digital image correlation strain and local compressive engineering strain. According to the results, the through-width sub-regions over an axial length between the average (lower bound) and the maximum (upper bound) of cell size should be used to characterise the meso-scale heterogeneity of the cell structure and deformation. It was found that the first crush band forms in a sub-region where the ratio of cell-wall thickness to cell-wall length is a minimum, in which the collapse deformation is dominated by the plastic bending and buckling of cell walls. Other morphological parameters have secondary effect on the initiation of crush band in the 2D foam. The finding of this study suggests that the measurement of local structural properties is crucial for the identification of the “weakest” region which determines the initiation of collapse and hence the corresponding collapse load of a heterogeneous cellular material.

  5. Improvement of Hydrological Simulations by Applying Daily Precipitation Interpolation Schemes in Meso-Scale Catchments

    Directory of Open Access Journals (Sweden)

    Mateusz Szcześniak

    2015-02-01

    Full Text Available Ground-based precipitation data are still the dominant input type for hydrological models. Spatial variability in precipitation can be represented by spatially interpolating gauge data using various techniques. In this study, the effect of daily precipitation interpolation methods on discharge simulations using the semi-distributed SWAT (Soil and Water Assessment Tool model over a 30-year period is examined. The study was carried out in 11 meso-scale (119–3935 km2 sub-catchments lying in the Sulejów reservoir catchment in central Poland. Four methods were tested: the default SWAT method (Def based on the Nearest Neighbour technique, Thiessen Polygons (TP, Inverse Distance Weighted (IDW and Ordinary Kriging (OK. =The evaluation of methods was performed using a semi-automated calibration program SUFI-2 (Sequential Uncertainty Fitting Procedure Version 2 with two objective functions: Nash-Sutcliffe Efficiency (NSE and the adjusted R2 coefficient (bR2. The results show that: (1 the most complex OK method outperformed other methods in terms of NSE; and (2 OK, IDW, and TP outperformed Def in terms of bR2. The median difference in daily/monthly NSE between OK and Def/TP/IDW calculated across all catchments ranged between 0.05 and 0.15, while the median difference between TP/IDW/OK and Def ranged between 0.05 and 0.07. The differences between pairs of interpolation methods were, however, spatially variable and a part of this variability was attributed to catchment properties: catchments characterised by low station density and low coefficient of variation of daily flows experienced more pronounced improvement resulting from using interpolation methods. Methods providing higher precipitation estimates often resulted in a better model performance. The implication from this study is that appropriate consideration of spatial precipitation variability (often neglected by model users that can be achieved using relatively simple interpolation methods can

  6. Quantitative modelling of the closure of meso-scale parallel currents in the nightside ionosphere

    Directory of Open Access Journals (Sweden)

    A. Marchaudon

    2004-01-01

    Full Text Available On 12 January 2000, during a northward IMF period, two successive conjunctions occur between the CUTLASS SuperDARN radar pair and the two satellites Ørsted and FAST. This situation is used to describe and model the electrodynamic of a nightside meso-scale arc associated with a convection shear. Three field-aligned current sheets, one upward and two downward on both sides, are observed. Based on the measurements of the parallel currents and either the conductance or the electric field profile, a model of the ionospheric current closure is developed along each satellite orbit. This model is one-dimensional, in a first attempt and a two-dimensional model is tested for the Ørsted case. These models allow one to quantify the balance between electric field gradients and ionospheric conductance gradients in the closure of the field-aligned currents. These radar and satellite data are also combined with images from Polar-UVI, allowing for a description of the time evolution of the arc between the two satellite passes. The arc is very dynamic, in spite of quiet solar wind conditions. Periodic enhancements of the convection and of electron precipitation associated with the arc are observed, probably associated with quasi-periodic injections of particles due to reconnection in the magnetotail. Also, a northward shift and a reorganisation of the precipitation pattern are observed, together with a southward shift of the convection shear. Key words. Ionosphere (auroral ionosphere; electric fields and currents; particle precipitation – Magnetospheric physics (magnetosphere-ionosphere interactions

  7. Combined meso-scale modeling and experimental investigation of the effect of mechanical damage on the transport properties of cementitious composites

    Science.gov (United States)

    Raghavan, Balaji; Niknezhad, Davood; Bernard, Fabrice; Kamali-Bernard, Siham

    2016-09-01

    The transport properties of cementitious composites such as concrete are important indicators of their durability, and are known to be heavily influenced by mechanical loading. In the current work, we use meso-scale hygro-mechanical modeling with a morphological 3D two phase mortar-aggregate model, in conjunction with experimentally obtained properties, to investigate the coupling between mechanical loading and damage and the permeability of the composite. The increase in permeability of a cylindrical test specimen at 28% aggregate fraction during a uniaxial displacement-controlled compression test at 85% of the peak load was measured using a gas permeameter. The mortar's mechanical behavior is assumed to follow the well-known compression damaged plasticity (CDP) model with isotropic damage, at varying thresholds, and obtained from different envelope curves. The damaged intrinsic permeability of the mortar evolves according to a logarithmic matching law with progressive loading. We fit the matching law parameters to the experimental result for the test specimen by inverse identification using our meso-scale model. We then subject a series of virtual composite specimens to quasi-static uniaxial compressive loading with varying boundary conditions to obtain the simulated damage and strain evolutions, and use the damage data and the previously identified parameters to determine the evolution of the macroscopic permeability tensor for the specimens, using a network model. We conduct a full parameter study by varying aggregate volume fraction, granulometric distribution, loading/boundary conditions and "matching law" parameters, as well as for different strain-damage thresholds and uniaxial loading envelope curves. Based on this study, we propose Avrami equation-based upper and lower bounds for the evolution of the damaged permeability of the composite.

  8. Rotational Motion Control of a Spacecraft

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2001-01-01

    The paper adopts the energy shaping method to control of rotational motion. A global representation of the rigid body motion is given in the canonical form by a quaternion and its conjugate momenta. A general method for motion control on a cotangent bundle to the 3-sphere is suggested. The design...... algorithm is validated for three-axis spacecraft attitude control...

  9. Rotational motion control of a spacecraft

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2003-01-01

    The paper adopts the energy shaping method to control of rotational motion. A global representation of the rigid body motion is given in the canonical form by a quaternion and its conjugate momenta. A general method for motion control on a cotangent bundle to the 3-sphere is suggested. The design...... algorithm is validated for three-axis spacecraft attitude control. Udgivelsesdato: APR...

  10. Meso-Scale Modeling of Spall in a Heterogeneous Two-Phase Material

    Energy Technology Data Exchange (ETDEWEB)

    Springer, Harry Keo [Univ. of California, Davis, CA (United States)

    2008-07-11

    The influence of the heterogeneous second-phase particle structure and applied loading conditions on the ductile spall response of a model two-phase material was investigated. Quantitative metallography, three-dimensional (3D) meso-scale simulations (MSS), and small-scale spall experiments provided the foundation for this study. Nodular ductile iron (NDI) was selected as the model two-phase material for this study because it contains a large and readily identifiable second- phase particle population. Second-phase particles serve as the primary void nucleation sites in NDI and are, therefore, central to its ductile spall response. A mathematical model was developed for the NDI second-phase volume fraction that accounted for the non-uniform particle size and spacing distributions within the framework of a length-scale dependent Gaussian probability distribution function (PDF). This model was based on novel multiscale sampling measurements. A methodology was also developed for the computer generation of representative particle structures based on their mathematical description, enabling 3D MSS. MSS were used to investigate the effects of second-phase particle volume fraction and particle size, loading conditions, and physical domain size of simulation on the ductile spall response of a model two-phase material. MSS results reinforce existing model predictions, where the spall strength metric (SSM) logarithmically decreases with increasing particle volume fraction. While SSM predictions are nearly independent of applied load conditions at lower loading rates, which is consistent with previous studies, loading dependencies are observed at higher loading rates. There is also a logarithmic decrease in SSM for increasing (initial) void size, as well. A model was developed to account for the effects of loading rate, particle size, matrix sound-speed, and, in the NDI-specific case, the probabilistic particle volume fraction model. Small-scale spall experiments were designed

  11. Information processing in micro and meso-scale neural circuits during normal and disease states

    Science.gov (United States)

    Luongo, Francisco

    Neural computation can occur at multiple spatial and temporal timescales. The sum total of all of these processes is to guide optimal behaviors within the context of the constraints imposed by the physical world. How the circuits of the brain achieves this goal represents a central question in systems neuroscience. Here I explore the many ways in which the circuits of the brain can process information at both the micro and meso scale. Understanding the way information is represented and processed in the brain could shed light on the neuropathology underlying complex neuropsychiatric diseases such as autism and schizophrenia. Chapter 2 establishes an experimental paradigm for assaying patterns of microcircuit activity and examines the role of dopaminergic modulation on prefrontal microcircuits. We find that dopamine type 2 (D2) receptor activation results in an increase in spontaneous activity while dopamine type 1 (D1) activation does not. Chapter 3 of this dissertation presents a study that illustrates how cholingergic activation normally produces what has been suggested as a neural substrate of attention; pairwise decorrelation in microcircuit activity. This study also shows that in two etiologicall distinct mouse models of autism, FMR1 knockout mice and Valproic Acid exposed mice, this ability to decorrelate in the presence of cholinergic activation is lost. This represents a putative microcircuit level biomarker of autism. Chapter 4 examines the structure/function relationship within the prefrontal microcircuit. Spontaneous activity in prefrontal microcircuits is shown to be organized according to a small world architecture. Interestingly, this architecture is important for one concrete function of neuronal microcircuits; the ability to produce temporally stereotyped patterns of activation. In the final chapter, we identify subnetworks in chronic intracranial electrocorticographic (ECoG) recordings using pairwise electrode coherence and dimensionality reduction

  12. The Heterotrophic Bacterial Response During the Meso-scale Southern Ocean Iron Experiment (SOFeX)

    Science.gov (United States)

    Oliver, J. L.; Barber, R. T.; Ducklow, H. W.

    2002-12-01

    Previous meso-scale iron enrichments have demonstrated the stimulatory effect of iron on primary productivity and the accelerated flow of carbon into the surface ocean foodweb. In stratified waters, heterotrophic activity can work against carbon export by remineralizing POC and/or DOC back to CO2, effectively slowing the biological pump. To assess the response of heterotrophic activity to iron enrichment, we measured heterotrophic bacterial production and abundance during the Southern Ocean Iron Experiment (SOFeX). Heterotrophic bacterial processes primarily affect the latter of the two carbon export mechanisms, removal of DOC to the deep ocean. Heterotrophic bacterial production (BP), measured via tritiated thymidine (3H-TdR) and leucine (3H-Leu) incorporation, increased ~40% over the 18-d observation period in iron fertilized waters south of the Polar Front (South Patch). Also, South Patch BP was 61% higher than in the surrounding unfertilized waters. Abundance, measured by flow cytometry (FCM) and acridine orange direct counts (AODC), also increased in the South Patch from 3 to 5 x 108 cells liter-1, a 70% increase. Bacterial biomass increased from ~3.6 to 6.3 μg C liter-1, a clear indication that production rates exceeded removal rates (bactivory, viral lysis) over the course of 18 days. Biomass within the fertilized patch was 11% higher than in surrounding unfertilized waters reflecting a similar trend. This pattern is in contrast to SOIREE where no accumulation of biomass was observed. High DNA-containing (HDNA) cells detected by FCM also increased over time in iron fertilized waters from 20% to 46% relative to the total population suggesting an active subpopulation of cells that were growing faster than the removal rates. In iron fertilized waters north of the Polar Front (North Patch), BP and abundance were ~90% and 80% higher, respectively, than in unfertilized waters. Our results suggest an active bacterial population that responded to iron fertilization

  13. Thermal performance of a meso-scale liquid-fuel combustor

    International Nuclear Information System (INIS)

    Vijayan, V.; Gupta, A.K.

    2011-01-01

    Research highlights: → Demonstrated successful combustion of liquid fuel-air mixtures in a novel meso-scale combustor. → Flame quenching was eliminated using heat recirculation in a swiss roll type combustor that also extended the flammability limits. → Liquid fuel was rapidly vaporized with the use of hot narrow channel walls that eliminated the need of a fuel atomizer. → Maximum power density of the combustor was estimated to be about 8.5 GW/m3 and heat load in the range of 50-280W. → Overall efficiency of the combustor was estimated in the range of 12 to 20%. - Abstract: Combustion in small scale devices poses significant challenges due to the quenching of reactions from wall heat losses as well as the significantly reduced time available for mixing and combustion. In the case of liquid fuels there are additional challenges related to atomization, vaporization and mixing with the oxidant in the very short time-scale liquid-fuel combustor. The liquid fuel employed here is methanol with air as the oxidizer. The combustor was designed based on the heat recirculating concept wherein the incoming reactants are preheated by the combustion products through heat exchange occurring via combustor walls. The combustor was fabricated from Zirconium phosphate, a ceramic with very low thermal conductivity (0.8 W m -1 K -1 ). The combustor had rectangular shaped double spiral geometry with combustion chamber in the center of the spiral formed by inlet and exhaust channels. Methanol and air were introduced immediately upstream at inlet of the combustor. The preheated walls of the inlet channel also act as a pre-vaporizer for liquid fuel which vaporizes the liquid fuel and then mixes with air prior to the fuel-air mixture reaching the combustion chamber. Rapid pre-vaporization of the liquid fuel by the hot narrow channel walls eliminated the necessity for a fuel atomizer. Self-sustained combustion of methanol-air was achieved in a chamber volume as small as 32.6 mm 3

  14. Wire Scanner Motion Control Card

    CERN Document Server

    Forde, S E

    2006-01-01

    Scientists require a certain beam quality produced by the accelerator rings at CERN. The discovery potential of LHC is given by the reachable luminosity at its interaction points. The luminosity is maximized by minimizing the beam size. Therefore an accurate beam size measurement is required for optimizing the luminosity. The wire scanner performs very accurate profile measurements, but as it can not be used at full intensity in the LHC ring, it is used for calibrating other profile monitors. As the current wire scanner system, which is used in the present CERN accelerators, has not been made for the required specification of the LHC, a new design of a wire scanner motion control card is part of the LHC wire scanner project. The main functions of this card are to control the wire scanner motion and to acquire the position of the wire. In case of further upgrades at a later stage, it is required to allow an easy update of the firmware, hence the programmable features of FPGAs will be used for this purpose. The...

  15. Evaluation of planetary boundary layer schemes in meso-scale simulations above the North and Baltic Sea

    Science.gov (United States)

    Wurps, Hauke; Tambke, Jens; Steinfeld, Gerald; von Bremen, Lueder

    2014-05-01

    The development and design of wind energy converters for offshore wind farms require profound knowledge of the wind profile in the lower atmosphere. Especially an accurate and reliable estimation of turbulence, shear and veer are necessary for the prediction of energy production and loads. Currently existing wind energy turbines in the North Sea have hub heights of around 90 m and upper tip heights around 150 m, which is already higher than the highest measurement masts (e.g. FINO1: 103 m). The next generation of wind turbines will clearly outrange these altitudes, so the interest is to examine the atmosphere's properties above the North Sea up to 300 m. Therefore, besides the Prandtl layer also the Ekman layer has to be taken into account, which implies that changes of the wind direction with height become more relevant. For this investigation we use the Weather Research and Forecasting Model (WRF), a meso-scale numerical weather prediction system. In this study we compare different planetary boundary layer (PBL) schemes (MYJ, MYNN, QNSE) with the same high quality input from ECMWF used as boundary conditions (ERA-Interim). It was found in previous studies that the quality of the boundary conditions is crucially important for the accuracy of comparisons between different PBL schemes. This is due to the fact that the major source of meso-scale simulation errors is introduced by the driving boundary conditions and not by the different schemes of the meso-scale model itself. Hence, small differences in results from different PBL schemes can be distorted arbitrarily by coarse input data. For instance, ERA-Interim data leads to meso-scale RMSE values of 1.4 m/s at 100 m height above sea surface with mean wind speeds around 10 m/s, whereas other Reanalysis products lead to RMSEs larger than 2 m/s. Second, we compare our simulations to operational NWP results from the COSMO model (run by the DWD). In addition to the wind profile, also the turbulent kinetic energy (TKE

  16. Meso-Scale Modelling of Deformation, Damage and Failure in Dual Phase Steels

    Science.gov (United States)

    Sari Sarraf, Iman

    Advanced high strength steels (AHSS), such as dual phase (DP) and transformation induced plasticity (TRIP) steels, offer high ductility, formability, and strength, as well as high strength-to-weight ratio and improved crash resistance. Dual phase steels belong to a family of high strength grades which consist of martensite, responsible for strengthening, distributed in a ductile ferrite matrix which accommodates the deformation throughout the forming process. It has been shown that the predominant damage mechanism and failure in DP steels depends on the ferrite and martensite grain sizes and their morphology, and can range from a mixture of brittle and ductile rupture to completely ductile rupture in a quasi-static uniaxial tension test. In this study, a hybrid finite element cellular automata model, initially proposed by Anton Shterenlikht (2003), was developed to evaluate the forming behaviour and predict the onset of instability and damage evolution in a dual phase steel. In this model, the finite element constitutive model is used to represent macro-level strain gradients and a damage variable, and two different cell arrays are designed to represent the ductile and brittle fracture modes in meso-scale. In the FE part of the model, a modified Rousselier ductile damage model is developed to account for nucleation, growth and coalescence of voids. Also, several rate-dependent hardening models were developed and evaluated to describe the work hardening flow curve of DP600. Based on statistical analysis and simulation results, a modified Johnson-Cook (JC) model and a multiplicative combination of the Voce-modified JC functions were found to be the most accurate hardening models. The developed models were then implemented in a user-defined material subroutine (VUMAT) for ABAQUS/Explicit finite element simulation software to simulate uniaxial tension tests at strain rates ranging from 0.001 1/s to 1000 1/s, Marciniak tests, and electrohydraulic free-forming (EHFF

  17. Design and fabrication of a meso-scale stirling engine and combustor.

    Energy Technology Data Exchange (ETDEWEB)

    Echekki, Tarek (Sandia National Laboratories, Livermore, CA); Haroldsen, Brent L. (Sandia National Laboratories, Livermore, CA); Krafcik, Karen L. (Sandia National Laboratories, Livermore, CA); Morales, Alfredo Martin (Sandia National Laboratories, Livermore, CA); Mills, Bernice E. (Sandia National Laboratories, Livermore, CA); Liu, Shiling (Sandia National Laboratories, Livermore, CA); Lee, Jeremiah C. (Sandia National Laboratories, Livermore, CA); Karpetis, Adionos N. (Sandia National Laboratories, Livermore, CA); Chen, Jacqueline H. (Sandia National Laboratories, Livermore, CA); Ceremuga, Joseph T. (Sandia National Laboratories, Livermore, CA); Raber, Thomas N. (Sandia National Laboratories, Livermore, CA); Hekmuuaty, Michelle A. (Sandia National Laboratories, Livermore, CA)

    2005-05-01

    Power sources capable of supplying tens of watts are needed for a wide variety of applications including portable electronics, sensors, micro aerial vehicles, and mini-robotics systems. The utility of these devices is often limited by the energy and power density capabilities of batteries. A small combustion engine using liquid hydrocarbon fuel could potentially increase both power and energy density by an order of magnitude or more. This report describes initial development work on a meso-scale external combustion engine based on the Stirling cycle. Although other engine designs perform better at macro-scales, we believe the Stirling engine cycle is better suited to small-scale applications. The ideal Stirling cycle requires efficient heat transfer. Consequently, unlike other thermodynamic cycles, the high heat transfer rates that are inherent with miniature devices are an advantage for the Stirling cycle. Furthermore, since the Stirling engine uses external combustion, the combustor and engine can be scaled and optimized semi-independently. Continuous combustion minimizes issues with flame initiation and propagation. It also allows consideration of a variety of techniques to promote combustion that would be difficult in a miniature internal combustion engine. The project included design and fabrication of both the engine and the combustor. Two engine designs were developed. The first used a cylindrical piston design fabricated with conventional machining processes. The second design, based on the Wankel rotor geometry, was fabricated by through-mold electroforming of nickel in SU8 and LIGA micromolds. These technologies provided the requisite precision and tight tolerances needed for efficient micro-engine operation. Electroformed nickel is ideal for micro-engine applications because of its high strength and ductility. A rotary geometry was chosen because its planar geometry was more compatible with the fabrication process. SU8 lithography provided rapid

  18. Robot motion control in mobile environment

    Institute of Scientific and Technical Information of China (English)

    Iliya V Miroshnik; HUANG Xian-lin(黄显林); HE Jie(贺杰)

    2003-01-01

    With the problem of robot motion control in dynamic environment represented by mobile obstacles,working pieces and external mechanisms considered, a relevant control actions design procedure has been pro-posed to provide coordination of robot motions with respect to the moving external objects so that an extension ofrobot spatial motion techniques and active robotic strategies based on approaches of nonlinear control theory canbe achieved.

  19. Meso-scale modelling of the heat conductivity effect on the shock response of a porous material

    Science.gov (United States)

    Resnyansky, A. D.

    2017-06-01

    Understanding of deformation mechanisms of porous materials under shock compression is important for tailoring material properties at the shock manufacturing of advanced materials from substrate powders and for studying the response of porous materials under shock loading. Numerical set-up of the present work considers a set of solid particles separated by air representing a volume of porous material. Condensed material in the meso-scale set-up is simulated with a viscoelastic rate sensitive material model with heat conduction formulated from the principles of irreversible thermodynamics. The model is implemented in the CTH shock physics code. The meso-scale CTH simulation of the shock loading of the representative volume reveals the mechanism of pore collapse and shows in detail the transition from a high porosity case typical for abnormal Hugoniot response to a moderate porosity case typical for conventional Hugoniot response. Results of the analysis agree with previous analytical considerations and support hypotheses used in the two-phase approach.

  20. Exoskeleton Motion Control for Children Walking Rehabilitation

    Directory of Open Access Journals (Sweden)

    Cristina Ploscaru

    2016-06-01

    Full Text Available This paper introduces a quick method for motion control of an exoskeleton used on children walking rehabilitation with ages between four to seven years old. The exoskeleton used on this purpose has six servomotors which work independently and actuates each human lower limb joints (hips, knees and ankles. For obtaining the desired motion laws, a high-speed motion analysis equipment was used. The experimental rough data were mathematically modeled in order to obtain the proper motion equations for controlling the exoskeleton servomotors.

  1. Tracer experiment data sets for the verification of local and meso-scale atmospheric dispersion models including topographic effects

    International Nuclear Information System (INIS)

    Sartori, E.; Schuler, W.

    1992-01-01

    Software and data for nuclear energy applications are acquired, tested and distributed by several information centres; in particular, relevant computer codes are distributed internationally by the OECD/NEA Data Bank (France) and by ESTSC and EPIC/RSIC (United States). This activity is coordinated among the centres and is extended outside the OECD area through an arrangement with the IAEA. This article proposes more specifically a scheme for acquiring, storing and distributing atmospheric tracer experiment data (ATE) required for verification of atmospheric dispersion models especially the most advanced ones including topographic effects and specific to the local and meso-scale. These well documented data sets will form a valuable complement to the set of atmospheric dispersion computer codes distributed internationally. Modellers will be able to gain confidence in the predictive power of their models or to verify their modelling skills. (au)

  2. The instability characteristics of lean premixed hydrogen and syngas flames stabilized on meso-scale bluff-body

    KAUST Repository

    Kim, Yu Jeong

    2017-01-05

    Bluff-body flame stabilization has been used as one of main flame stabilization schemes to improve combustion stability in both large and small scale premixed combustion systems. The detailed investigation of instability characteristics is needed to understand flame stability mechanism. Direct numerical simulations are conducted to investigate flame dynamics on the instability of lean premixed hydrogen/air and syngas/air flames stabilized on a meso-scale bluff-body. A two-dimensional channel of 10 mm height and 10 mm length with a square bluff-body stabilizer of 0.5 mm is considered. The height of domain is chosen as an unconfined condition to minimize the effect of the blockage ratio. Flame/flow dynamics are observed by increasing the mean inflow velocity from a steady stable to unsteady asymmetrical instability, followed by blowoff. Detailed observations between hydrogen and syngas flames with a time scale analysis are presented.

  3. A dual theory of price and value in a meso-scale economic model with stochastic profit rate

    Science.gov (United States)

    Greenblatt, R. E.

    2014-12-01

    The problem of commodity price determination in a market-based, capitalist economy has a long and contentious history. Neoclassical microeconomic theories are based typically on marginal utility assumptions, while classical macroeconomic theories tend to be value-based. In the current work, I study a simplified meso-scale model of a commodity capitalist economy. The production/exchange model is represented by a network whose nodes are firms, workers, capitalists, and markets, and whose directed edges represent physical or monetary flows. A pair of multivariate linear equations with stochastic input parameters represent physical (supply/demand) and monetary (income/expense) balance. The input parameters yield a non-degenerate profit rate distribution across firms. Labor time and price are found to be eigenvector solutions to the respective balance equations. A simple relation is derived relating the expected value of commodity price to commodity labor content. Results of Monte Carlo simulations are consistent with the stochastic price/labor content relation.

  4. Kinematics and Dynamics of Motion Control Based on Acceleration Control

    Science.gov (United States)

    Ohishi, Kiyoshi; Ohba, Yuzuru; Katsura, Seiichiro

    The first IEEE International Workshop on Advanced Motion Control was held in 1990 pointed out the importance of physical interpretation of motion control. The software servoing technology is now common in machine tools, robotics, and mechatronics. It has been intensively developed for the numerical control (NC) machines. Recently, motion control in unknown environment will be more and more important. Conventional motion control is not always suitable due to the lack of adaptive capability to the environment. A more sophisticated ability in motion control is necessary for compliant contact with environment. Acceleration control is the key technology of motion control in unknown environment. The acceleration control can make a motion system to be a zero control stiffness system without losing the robustness. Furthermore, a realization of multi-degree-of-freedom motion is necessary for future human assistance. A human assistant motion will require various control stiffness corresponding to the task. The review paper focuses on the modal coordinate system to integrate the various control stiffness in the virtual axes. A bilateral teleoperation is a good candidate to consider the future human assistant motion and integration of decentralized systems. Thus the paper reviews and discusses the bilateral teleoperation from the control stiffness and the modal control design points of view.

  5. Muscle Synergy-Driven Robust Motion Control.

    Science.gov (United States)

    Min, Kyuengbo; Iwamoto, Masami; Kakei, Shinji; Kimpara, Hideyuki

    2018-04-01

    Humans are able to robustly maintain desired motion and posture under dynamically changing circumstances, including novel conditions. To accomplish this, the brain needs to optimize the synergistic control between muscles against external dynamic factors. However, previous related studies have usually simplified the control of multiple muscles using two opposing muscles, which are minimum actuators to simulate linear feedback control. As a result, they have been unable to analyze how muscle synergy contributes to motion control robustness in a biological system. To address this issue, we considered a new muscle synergy concept used to optimize the synergy between muscle units against external dynamic conditions, including novel conditions. We propose that two main muscle control policies synergistically control muscle units to maintain the desired motion against external dynamic conditions. Our assumption is based on biological evidence regarding the control of multiple muscles via the corticospinal tract. One of the policies is the group control policy (GCP), which is used to control muscle group units classified based on functional similarities in joint control. This policy is used to effectively resist external dynamic circumstances, such as disturbances. The individual control policy (ICP) assists the GCP in precisely controlling motion by controlling individual muscle units. To validate this hypothesis, we simulated the reinforcement of the synergistic actions of the two control policies during the reinforcement learning of feedback motion control. Using this learning paradigm, the two control policies were synergistically combined to result in robust feedback control under novel transient and sustained disturbances that did not involve learning. Further, by comparing our data to experimental data generated by human subjects under the same conditions as those of the simulation, we showed that the proposed synergy concept may be used to analyze muscle synergy

  6. Jerk derivative feedforward control for motion systems

    NARCIS (Netherlands)

    Boerlage, M.L.G.; Tousain, R.L.; Steinbuch, M.

    2004-01-01

    This work discusses reference trajectory relevant model based feedforward design. For motion systems which contain at least one rigid body mode and which are subject to reference trajectories with mostly low frequency energy, the proposed feedforward controller improves tracking performance

  7. Characterisation of stable isotopes to identify residence times and runoff components in two meso-scale catchments in the Abay/Upper Blue Nile basin, Ethiopia

    NARCIS (Netherlands)

    Tekleab, S.; Wenninger, J.W.; Uhlenbrook, S.

    2014-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin, as

  8. Identifying residence times and streamflow generation processes using ?18O and ?2H in meso-scale catchments in the Abay/Upper Blue Nile, Ethiopia

    NARCIS (Netherlands)

    Teklaeb, S.; Wenninger, J.W.; Uhlenbrook, S.

    2013-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin.

  9. Advanced Controllers for Electromechanical Motion Systems

    NARCIS (Netherlands)

    Nguyen, Duy Cuong

    2008-01-01

    The aim of this research is to develop advanced controllers for electromechanical motion systems. In order to increase efficiency and reliability, these control systems are required to achieve high performance and robustness in the face of model uncertainty, measurement noise, and reproducible

  10. Meso-scale Modeling of Block Copolymers Self-Assembly in Casting Solutions for Membrane Manufacture

    KAUST Repository

    Moreno Chaparro, Nicolas

    2016-01-01

    Isoporous membranes manufactured from diblock copolymer are successfully produced at laboratory scale under controlled conditions. Because of the complex phenomena involved, membrane preparation requires trial and error methodologies to find

  11. Short-term meso-scale variability of mesozooplankton communities in a coastal upwelling system (NW Spain)

    Science.gov (United States)

    Roura, Álvaro; Álvarez-Salgado, Xosé A.; González, Ángel F.; Gregori, María; Rosón, Gabriel; Guerra, Ángel

    2013-02-01

    The short-term, meso-scale variability of the mesozooplankton community present in the coastal upwelling system of the Ría de Vigo (NW Spain) has been analysed. Three well-defined communities were identified: coastal, frontal and oceanic, according to their holoplankton-meroplankton ratio, richness, and total abundance. These communities changed from summer to autumn due to a shift from downwelling to upwelling-favourable conditions coupled with taxa dependent changes in life strategies. Relationships between the resemblance matrix of mesozooplankton and the resemblance matrices of meteorologic, hydrographic and community-derived biotic variables were determined with distance-based linear models (DistLM, 18 variables), showing an increasing amount of explained variability of 6%, 16.1% and 54.5%, respectively. A simplified model revealed that the variability found in the resemblance matrix of mesozooplankton was mainly described by the holoplankton-meroplankton ratio, the total abundance, the influence of lunar cycles, the upwelling index and the richness; altogether accounting for 64% of the total variability. The largest variability of the mesozooplankton resemblance matrix (39.6%) is accounted by the holoplankton-meroplankton ratio, a simple index that describes appropriately the coastal-ocean gradient. The communities described herein kept their integrity in the studied upwelling and downwelling episodes in spite of the highly advective environment off the Ría de Vigo, presumably due to behavioural changes in the vertical position of the zooplankton.

  12. Development of a portable power system with meso-scale vortex combustor and thermo-electric device

    International Nuclear Information System (INIS)

    Shimokuri, D; Hara, T; Ishizuka, S

    2014-01-01

    In this study, a small scale power generation system with a meso-scale vortex combustor has been developed. The system was consisted of a couple of thermo-electric device and a heat medium. The medium was made of duralumin, 40 × 40 × 20 mm and 52 g weight, and the vortex combustion chamber of 7 mm inner diameter was embedded in it. It was found that a stable flame could be established in the narrow 7 mm channel even the mean axial velocity reached 1.2 m/s. And furthermore, the vortex flow significantly enhanced the heat transfer from the burned gas to combustion chamber, and as a result, the medium was heated to 300°C quickly (within 5 minutes) by the combustion of propane / air mixture for 145W input energy. The system could successfully generate 1.98 W (4.3 V and 0.46 A), which corresponded to the energy conversion rate of 0.7 % per unit thermo-electric device

  13. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Science.gov (United States)

    Jolley, Katherine E

    2015-01-01

    Summary The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates. PMID:26734089

  14. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Directory of Open Access Journals (Sweden)

    A. John Blacker

    2015-12-01

    Full Text Available The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  15. Study of the Arrangement Effect of Units on the Shear Strength Masonry Walls in Meso-Scale

    Directory of Open Access Journals (Sweden)

    M. Sepehrinia

    2016-12-01

    Full Text Available Masonry is one of the oldest building materials which have been used in most heritage structures and new construction. In this study by using a meso-scale finite element model, the behavior of masonry walls is investigated under monotonic loading by Abaqus software. The most important factor in determining the behavior of masonry structures is discontinuity joints which are interface between unit and mortar. In most previous studies cohesive element is used for modeling of interface element. But in this study, by ignoring cohesive elements that represents the interface element between unit and mortar in masonry structures, it can be seen that while reducing the computational requirements, the results are in good agreement with experimental studies. Another important factor in the behavior of masonry walls is the arrangement of masonry units. In this study the overlapping effect of rows of units on the shear strength and failure mode of masonry walls have been investigated. As a result, it was observed that by increasing overlap, shear resistance of masonry walls increased.

  16. Meso-Scale Progressive Damage Behavior Characterization of Triaxial Braided Composites under Quasi-Static Tensile Load

    Science.gov (United States)

    Ren, Yiru; Zhang, Songjun; Jiang, Hongyong; Xiang, Jinwu

    2018-04-01

    Based on continuum damage mechanics (CDM), a sophisticated 3D meso-scale finite element (FE) model is proposed to characterize the progressive damage behavior of 2D Triaxial Braided Composites (2DTBC) with 60° braiding angle under quasi-static tensile load. The modified Von Mises strength criterion and 3D Hashin failure criterion are used to predict the damage initiation of the pure matrix and fiber tows. A combining interface damage and friction constitutive model is applied to predict the interface damage behavior. Murakami-Ohno stiffness degradation scheme is employed to predict the damage evolution process of each constituent. Coupling with the ordinary and translational symmetry boundary conditions, the tensile elastic response including tensile strength and failure strain of 2DTBC are in good agreement with the available experiment data. The numerical results show that the main failure modes of the composites under axial tensile load are pure matrix cracking, fiber and matrix tension failure in bias fiber tows, matrix tension failure in axial fiber tows and interface debonding; the main failure modes of the composites subjected to transverse tensile load are free-edge effect, matrix tension failure in bias fiber tows and interface debonding.

  17. Meso-Scale Finite Element Analysis of Mechanical Behavior of 3D Braided Composites Subjected to Biaxial Tension Loadings

    Science.gov (United States)

    Zhang, Chao; Curiel-Sosa, Jose L.; Bui, Tinh Quoc

    2018-04-01

    In many engineering applications, 3D braided composites are designed for primary loading-bearing structures, and they are frequently subjected to multi-axial loading conditions during service. In this paper, a unit-cell based finite element model is developed for assessment of mechanical behavior of 3D braided composites under different biaxial tension loadings. To predict the damage initiation and evolution of braiding yarns and matrix in the unit-cell, we thus propose an anisotropic damage model based on Murakami damage theory in conjunction with Hashin failure criteria and maximum stress criteria. To attain exact stress ratio, force loading mode of periodic boundary conditions which never been attempted before is first executed to the unit-cell model to apply the biaxial tension loadings. The biaxial mechanical behaviors, such as the stress distribution, tensile modulus and tensile strength are analyzed and discussed. The damage development of 3D braided composites under typical biaxial tension loadings is simulated and the damage mechanisms are revealed in the simulation process. The present study generally provides a new reference to the meso-scale finite element analysis (FEA) of multi-axial mechanical behavior of other textile composites.

  18. Terahertz Generation & Vortex Motion Control in Superconductors

    Science.gov (United States)

    Nori, Franco

    2005-03-01

    A grand challenge is to controllably generate electromagnetic waves in layered superconducting compounds because of its Terahertz frequency range. We propose [1] four experimentally realizable devices for generating continuous and pulsed THz radiation in a controllable frequency range. We also describe [2-4] several novel devices for controlling the motion of vortices in superconductors, including a reversible rectifier made of a magnetic-superconducting hybrid structure [4]. Finally, we summarize a study [5] of the friction force felt by moving vortices. 1) S. Savel'ev, V. Yampol'skii, A. Rakhmanov, F. Nori, Tunable Terahertz radiation from Josephson vortices, preprint 2) S. Savel'ev and F. Nori, Experimentally realizable devices for controlling the motion of magnetic flux quanta, Nature Mat. 1, 179 (2002) 3) S. Savel'ev, F. Marchesoni, F. Nori, Manipulating small particles, PRL 92, 160602 (2004); B. Zhu, F. Marchesoni, F. Nori, Controlling the motion of magnetic flux quanta, PRL 92, 180602 (2004) 4) J.E. Villegas, et al., Reversible Rectifier that Controls the Motion of Magnetic Flux Quanta, Science 302, 1188 (2003) 5) A. Maeda, et al., Nano-scale friction: kinetic friction of magnetic flux quanta and charge density waves, preprint

  19. Controlling vortex motion and vortex kinetic friction

    International Nuclear Information System (INIS)

    Nori, Franco; Savel'ev, Sergey

    2006-01-01

    We summarize some recent results of vortex motion control and vortex kinetic friction. (1) We describe a device [J.E. Villegas, S. Savel'ev, F. Nori, E.M. Gonzalez, J.V. Anguita, R. Garcia, J.L. Vicent, Science 302 (2003) 1188] that can easily control the motion of flux quanta in a Niobium superconducting film on an array of nanoscale triangular magnets. Even though the input ac current has zero average, the resulting net motion of the vortices can be directed along either one direction, the opposite direction, or producing zero net motion. We also consider layered strongly anisotropic superconductors, with no fixed spatial asymmetry, and show [S. Savel'ev, F. Nori, Nature Materials 1 (2002) 179] how, with asymmetric drives, the ac motion of Josephson and/or pancake vortices can provide a net dc vortex current. (2) In analogy with the standard macroscopic friction, we present [A. Maeda, Y. Inoue, H. Kitano, S. Savel'ev, S. Okayasu, I. Tsukada, F. Nori , Phys. Rev. Lett. 94 (2005) 077001] a comparative study of the friction force felt by vortices in superconductors and charge density waves

  20. Controlling vortex motion and vortex kinetic friction

    Science.gov (United States)

    Nori, Franco; Savel'ev, Sergey

    2006-05-01

    We summarize some recent results of vortex motion control and vortex kinetic friction. (1) We describe a device [J.E. Villegas, S. Savel'ev, F. Nori, E.M. Gonzalez, J.V. Anguita, R. Garcìa, J.L. Vicent, Science 302 (2003) 1188] that can easily control the motion of flux quanta in a Niobium superconducting film on an array of nanoscale triangular magnets. Even though the input ac current has zero average, the resulting net motion of the vortices can be directed along either one direction, the opposite direction, or producing zero net motion. We also consider layered strongly anisotropic superconductors, with no fixed spatial asymmetry, and show [S. Savel'ev, F. Nori, Nature Materials 1 (2002) 179] how, with asymmetric drives, the ac motion of Josephson and/or pancake vortices can provide a net dc vortex current. (2) In analogy with the standard macroscopic friction, we present [A. Maeda, Y. Inoue, H. Kitano, S. Savel'ev, S. Okayasu, I. Tsukada, F. Nori , Phys. Rev. Lett. 94 (2005) 077001] a comparative study of the friction force felt by vortices in superconductors and charge density waves.

  1. Meso-scale Modeling of Block Copolymers Self-Assembly in Casting Solutions for Membrane Manufacture

    KAUST Repository

    Moreno Chaparro, Nicolas

    2016-05-01

    Isoporous membranes manufactured from diblock copolymer are successfully produced at laboratory scale under controlled conditions. Because of the complex phenomena involved, membrane preparation requires trial and error methodologies to find the optimal conditions, leading to a considerable demand of resources. Experimental insights demonstrate that the self-assembly of the block copolymers in solution has an effect on the final membrane structure. Nevertheless, the complete understanding of these multi-scale phenomena is elusive. Herein we use the coarse-grained method Dissipative Particle Dynamics to study the self-assembly of block copolymers that are used for the preparation of the membranes. To simulate representative time and length scales, we introduce a framework for model reduction of polymer chain representations for dissipative particle dynamics, which preserves the properties governing the phase equilibria. We reduce the number of degrees of freedom by accounting for the correlation between beads in fine-grained models via power laws and the consistent scaling of the simulation parameters. The coarse-graining models are consistent with the experimental evidence, showing a morphological transition of the aggregates as the polymer concentration and solvent affinity change. We show that hexagonal packing of the micelles can occur in solution within different windows of polymer concentration depending on the solvent affinity. However, the shape and size dispersion of the micelles determine the characteristic arrangement. We describe the order of crew-cut micelles using a rigid-sphere approximation and propose different phase parameters that characterize the emergence of monodisperse-spherical micelles in solution. Additionally, we investigate the effect of blending asymmetric diblock copolymers (AB/AC) over the properties of the membranes. We observe that the co-assembly mechanism localizes the AC molecules at the interface of A and B domains, and induces

  2. Meso-scale modeling of air pollution transport/chemistry/deposition and its application

    International Nuclear Information System (INIS)

    Kitada, Toshihiro

    2007-01-01

    Transport/chemistry/deposition model for atmospheric trace chemical species is now regarded as an important tool for an understanding of the effects of various human activities, such as fuel combustion and deforestation, on human health, eco-system, and climate and for planning of appropriate control of emission sources. Several 'comprehensive' models have been proposed such as RADM (Chang, et al., 1987), STEM-II (Carmichael, et al., 1986), and CMAQ (Community Multi-scale Air Quality model, e.g., EPA website, 2003); the 'comprehensive' models include not only gas/aerosol phase chemistry but also aqueous phase chemistry in cloud/rain water in addition to the processes of advection, diffusion, wet deposition (mass transfer between aqueous and gas/aerosol phases), and dry deposition. The target of the development of the 'comprehensive' model will be that the model can correctly reproduce mass balance of various chemical species in the atmosphere with keeping adequate accuracy for calculated concentration distributions of chemical species. For the purpose, one of the important problems is a reliable wet deposition modeling, and here, we introduce two types of methods of 'cloud-resolving' and 'non-cloud-resolving' modeling for the wet deposition of pollutants. (author)

  3. Modeling and identification for robot motion control

    NARCIS (Netherlands)

    Kostic, D.; Jager, de A.G.; Steinbuch, M.; Kurfess, T.R.

    2004-01-01

    This chapter deals with the problems of robot modelling and identification for high-performance model-based motion control. A derivation of robot kinematic and dynamic models was explained. Modelling of friction effects was also discussed. Use of a writing task to establish correctness of the models

  4. Motion control of the Twente humanoid head

    NARCIS (Netherlands)

    Visser, L.C.; Carloni, Raffaella; Stramigioli, Stefano

    2009-01-01

    In this work, we present the design and the realization of the motion control algorithm implemented in the Twente hu- manoid head, a seven degrees of freedom (dof) robotic sys- tem. The aim of the project is to have a humanoid head that can serve as a research platform for human-machine interac-

  5. Specification of EDITH motion control system

    International Nuclear Information System (INIS)

    Breitwieser, H.; Frank, A.; Holler, E.; Suess, U.; Leinemann, K.

    1990-09-01

    EDITH is an experimental device for in vessel handling at NET/ITER. The purpose of EDITH is: Testing of ABS (articulated boom system) components; testing and validation of remote handling procedures; testing and validation of ABS end-effectors; testing of ABS control system features and verification of control system concepts. This document, after describing the environment in which the control system is to operate, specifies architecture and functionality to be implemented by the EDITH motion control system software, thereby taking full reference to the control system specification for TARM, which was decided to be the base for the implementation. (orig.) [de

  6. Up-scaling of multi-variable flood loss models from objects to land use units at the meso-scale

    Directory of Open Access Journals (Sweden)

    H. Kreibich

    2016-05-01

    Full Text Available Flood risk management increasingly relies on risk analyses, including loss modelling. Most of the flood loss models usually applied in standard practice have in common that complex damaging processes are described by simple approaches like stage-damage functions. Novel multi-variable models significantly improve loss estimation on the micro-scale and may also be advantageous for large-scale applications. However, more input parameters also reveal additional uncertainty, even more in upscaling procedures for meso-scale applications, where the parameters need to be estimated on a regional area-wide basis. To gain more knowledge about challenges associated with the up-scaling of multi-variable flood loss models the following approach is applied: Single- and multi-variable micro-scale flood loss models are up-scaled and applied on the meso-scale, namely on basis of ATKIS land-use units. Application and validation is undertaken in 19 municipalities, which were affected during the 2002 flood by the River Mulde in Saxony, Germany by comparison to official loss data provided by the Saxon Relief Bank (SAB.In the meso-scale case study based model validation, most multi-variable models show smaller errors than the uni-variable stage-damage functions. The results show the suitability of the up-scaling approach, and, in accordance with micro-scale validation studies, that multi-variable models are an improvement in flood loss modelling also on the meso-scale. However, uncertainties remain high, stressing the importance of uncertainty quantification. Thus, the development of probabilistic loss models, like BT-FLEMO used in this study, which inherently provide uncertainty information are the way forward.

  7. Up-scaling of multi-variable flood loss models from objects to land use units at the meso-scale

    Science.gov (United States)

    Kreibich, Heidi; Schröter, Kai; Merz, Bruno

    2016-05-01

    Flood risk management increasingly relies on risk analyses, including loss modelling. Most of the flood loss models usually applied in standard practice have in common that complex damaging processes are described by simple approaches like stage-damage functions. Novel multi-variable models significantly improve loss estimation on the micro-scale and may also be advantageous for large-scale applications. However, more input parameters also reveal additional uncertainty, even more in upscaling procedures for meso-scale applications, where the parameters need to be estimated on a regional area-wide basis. To gain more knowledge about challenges associated with the up-scaling of multi-variable flood loss models the following approach is applied: Single- and multi-variable micro-scale flood loss models are up-scaled and applied on the meso-scale, namely on basis of ATKIS land-use units. Application and validation is undertaken in 19 municipalities, which were affected during the 2002 flood by the River Mulde in Saxony, Germany by comparison to official loss data provided by the Saxon Relief Bank (SAB).In the meso-scale case study based model validation, most multi-variable models show smaller errors than the uni-variable stage-damage functions. The results show the suitability of the up-scaling approach, and, in accordance with micro-scale validation studies, that multi-variable models are an improvement in flood loss modelling also on the meso-scale. However, uncertainties remain high, stressing the importance of uncertainty quantification. Thus, the development of probabilistic loss models, like BT-FLEMO used in this study, which inherently provide uncertainty information are the way forward.

  8. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    International Nuclear Information System (INIS)

    Serrato, M. G.

    2013-01-01

    The DOE Office of Environmental management (DOE EM) faces the challenge of decommissioning thousands of excess nuclear facilities, many of which are highly contaminated. A number of these excess facilities are massive and robust concrete structures that are suitable for isolating the contained contamination for hundreds of years, and a permanent decommissioning end state option for these facilities is in situ decommissioning (ISD). The ISD option is feasible for a limited, but meaningfull number of DOE contaminated facilities for which there is substantial incremental environmental, safety, and cost benefits versus alternate actions to demolish and excavate the entire facility and transport the rubble to a radioactive waste landfill. A general description of an ISD project encompasses an entombed facility; in some cases limited to the blow-grade portion of a facility. However, monitoring of the ISD structures is needed to demonstrate that the building retains its structural integrity and the contaminants remain entombed within the grout stabilization matrix. The DOE EM Office of Deactivation and Decommissioning and Facility Engineering (EM-13) Program Goal is to develop a monitoring system to demonstrate long-term performance of closed nuclear facilities using the ISD approach. The Savannah River National Laboratory (SRNL) has designed and implemented the In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) to address the feasibility of deploying a long-term monitoring system into an ISD closed nuclear facility. The ISDSN-MSTB goal is to demonstrate the feasibility of installing and operating a remote sensor network to assess cementitious material durability, moisture-fluid flow through the cementitious material, and resulting transport potential for contaminate mobility in a decommissioned closed nuclear facility. The original ISDSN-MSTB installation and remote sensor network operation was demonstrated in FY 2011-12 at the ISDSN-MSTB test cube

  9. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Serrato, M. G.

    2013-09-27

    The DOE Office of Environmental management (DOE EM) faces the challenge of decommissioning thousands of excess nuclear facilities, many of which are highly contaminated. A number of these excess facilities are massive and robust concrete structures that are suitable for isolating the contained contamination for hundreds of years, and a permanent decommissioning end state option for these facilities is in situ decommissioning (ISD). The ISD option is feasible for a limited, but meaningfull number of DOE contaminated facilities for which there is substantial incremental environmental, safety, and cost benefits versus alternate actions to demolish and excavate the entire facility and transport the rubble to a radioactive waste landfill. A general description of an ISD project encompasses an entombed facility; in some cases limited to the blow-grade portion of a facility. However, monitoring of the ISD structures is needed to demonstrate that the building retains its structural integrity and the contaminants remain entombed within the grout stabilization matrix. The DOE EM Office of Deactivation and Decommissioning and Facility Engineering (EM-13) Program Goal is to develop a monitoring system to demonstrate long-term performance of closed nuclear facilities using the ISD approach. The Savannah River National Laboratory (SRNL) has designed and implemented the In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) to address the feasibility of deploying a long-term monitoring system into an ISD closed nuclear facility. The ISDSN-MSTB goal is to demonstrate the feasibility of installing and operating a remote sensor network to assess cementitious material durability, moisture-fluid flow through the cementitious material, and resulting transport potential for contaminate mobility in a decommissioned closed nuclear facility. The original ISDSN-MSTB installation and remote sensor network operation was demonstrated in FY 2011-12 at the ISDSN-MSTB test cube

  10. Control Strategies for Guided Collective Motion

    Science.gov (United States)

    2015-02-27

    J.K. Parrish , “Oscillator models and collective motion,” IEEE Control Systems Magzine, Vol. 27, 2007, pp. 89-105. [18] S. H. Strogatz , “From Kuramoto...Automatic Control, 54(2), 2009, pp. 353-357. [21] H. Hong and S. H. Strogatz , “Kuramoto Model of Coupled Oscillators with Positive and Negative...2013) provided similar results by utilizing a modified Kuramoto model ( Strogatz (2000)). Paley (2008) proposed a Lyapunov-based design methodology to

  11. A unified bond theory, probabilistic meso-scale modeling, and experimental validation of deformed steel rebar in normal strength concrete

    Science.gov (United States)

    Wu, Chenglin

    Bond between deformed rebar and concrete is affected by rebar deformation pattern, concrete properties, concrete confinement, and rebar-concrete interfacial properties. Two distinct groups of bond models were traditionally developed based on the dominant effects of concrete splitting and near-interface shear-off failures. Their accuracy highly depended upon the test data sets selected in analysis and calibration. In this study, a unified bond model is proposed and developed based on an analogy to the indentation problem around the rib front of deformed rebar. This mechanics-based model can take into account the combined effect of concrete splitting and interface shear-off failures, resulting in average bond strengths for all practical scenarios. To understand the fracture process associated with bond failure, a probabilistic meso-scale model of concrete is proposed and its sensitivity to interface and confinement strengths are investigated. Both the mechanical and finite element models are validated with the available test data sets and are superior to existing models in prediction of average bond strength (rib spacing-to-height ratio of deformed rebar. It can accurately predict the transition of failure modes from concrete splitting to rebar pullout and predict the effect of rebar surface characteristics as the rib spacing-to-height ratio increases. Based on the unified theory, a global bond model is proposed and developed by introducing bond-slip laws, and validated with testing of concrete beams with spliced reinforcement, achieving a load capacity prediction error of less than 26%. The optimal rebar parameters and concrete cover in structural designs can be derived from this study.

  12. No Habitat Selection during Spring Migration at a Meso-Scale Range across Mosaic Landscapes: A Case Study with the Woodcock (Scolopax rusticola.

    Directory of Open Access Journals (Sweden)

    Ariñe Crespo

    Full Text Available Success of migration in birds in part depends on habitat selection. Overall, it is still poorly known whether there is habitat selection amongst landbird migrants moving across landscapes. Europe is chiefly covered by agro-forestry mosaic landscapes, so migratory species associated to either agricultural landscapes or woodland habitats should theoretically find suitable stopover sites along migration. During migration from wintering to breeding quarters, woodcocks (Scolopax rusticola tagged with PTT satellite-tracking transmitters were used to test for the hypothesis that migrants associated to agro-forest habitats have no habitat selection during migration, at a meso-scale level. Using a GIS platform we extracted at a meso-scale range habitat cover at stopover localities. Results obtained from comparisons of soil covers between points randomly selected and true stopover localities sites revealed, as expected, the species may not select for particular habitats at a meso-scale range, because the habitat (or habitats required by the species can be found virtually everywhere on their migration route. However, those birds stopping over in places richer in cropland or mosaic habitats including both cropland and forest and with proportionally less closed forest stayed for longer than in areas with lower surfaces of cropland and mosaic and more closed forest. This suggests that areas rich in cropland or mosaic habitat were optimal.

  13. The plane motion control of the quadrocopter

    Directory of Open Access Journals (Sweden)

    A. N. Kanatnikov

    2015-01-01

    Full Text Available Among a large number of modern flying vehicles, the quadrocopter relates to unmanned aerial vehicles (UAV which are relatively cheap and easy to design. Quadrocopters are able to fly in bad weather, hang in the air for quite a long time, observe the objects and perform many other tasks. They have been applied in rescue operations, in agriculture, in the military and many other fields.For quadrocopters, the problems of path planning and control are relevant. These problems have many variants in which limited resources of modern UAV, possible obstacles, for instance, for flying in a cross-country terrain or in a city environment and weather conditions (particularly, wind conditions are taken into account. Many research studies are concerned with these problems and reflected in series of publications (note the interesting survey [1] and references therein. Various methods were used for the control synthesis for these vehicles: linear approximations [2], sliding mode control [3], the covering method [4] and so on.In the paper, a quadrocopter is considered as a rigid body. The kinematic and dynamic equations of the motion are analyzed. Two cases of motion are emphasized: a motion in a vertical plane and in a horizontal plane. The control is based on transferring of the affine system to the canonical form [5] and the nonlinear stabilization method [6].

  14. Self versus environment motion in postural control.

    Directory of Open Access Journals (Sweden)

    Kalpana Dokka

    2010-02-01

    Full Text Available To stabilize our position in space we use visual information as well as non-visual physical motion cues. However, visual cues can be ambiguous: visually perceived motion may be caused by self-movement, movement of the environment, or both. The nervous system must combine the ambiguous visual cues with noisy physical motion cues to resolve this ambiguity and control our body posture. Here we have developed a Bayesian model that formalizes how the nervous system could solve this problem. In this model, the nervous system combines the sensory cues to estimate the movement of the body. We analytically demonstrate that, as long as visual stimulation is fast in comparison to the uncertainty in our perception of body movement, the optimal strategy is to weight visually perceived movement velocities proportional to a power law. We find that this model accounts for the nonlinear influence of experimentally induced visual motion on human postural behavior both in our data and in previously published results.

  15. Motion control of musculoskeletal systems with redundancy.

    Science.gov (United States)

    Park, Hyunjoo; Durand, Dominique M

    2008-12-01

    Motion control of musculoskeletal systems for functional electrical stimulation (FES) is a challenging problem due to the inherent complexity of the systems. These include being highly nonlinear, strongly coupled, time-varying, time-delayed, and redundant. The redundancy in particular makes it difficult to find an inverse model of the system for control purposes. We have developed a control system for multiple input multiple output (MIMO) redundant musculoskeletal systems with little prior information. The proposed method separates the steady-state properties from the dynamic properties. The dynamic control uses a steady-state inverse model and is implemented with both a PID controller for disturbance rejection and an artificial neural network (ANN) feedforward controller for fast trajectory tracking. A mechanism to control the sum of the muscle excitation levels is also included. To test the performance of the proposed control system, a two degree of freedom ankle-subtalar joint model with eight muscles was used. The simulation results show that separation of steady-state and dynamic control allow small output tracking errors for different reference trajectories such as pseudo-step, sinusoidal and filtered random signals. The proposed control method also demonstrated robustness against system parameter and controller parameter variations. A possible application of this control algorithm is FES control using multiple contact cuff electrodes where mathematical modeling is not feasible and the redundancy makes the control of dynamic movement difficult.

  16. Simulation of atmospheric temperature inversions over greater cairo using the MM5 Meso-Scale atmospheric model

    International Nuclear Information System (INIS)

    Kandil, H.A.; Elhadidi, B.M.; Kader, A. A.; Moaty, A.A.; Sherif, A.O.

    2006-01-01

    Air pollution episodes have been recorded in Cairo, during the fall season, since 1999, as a result of specific meteorological conditions combined with large quantity of pollutants created by several ground-based sources. The main reason for the smog-like episodes (black clouds) is adverse weather conditions with low and variable winds, high humidity and strong temperature inversions in the few-hundred meters above the ground. The two important types of temperature inversion affecting the air pollution are surface or ground (radiation) inversion and subsidence (elevated) inversion. The surface temperature inversion is associated with a rapid decrease in the ground surface temperature with the simultaneous existence of warm air in the lower troposphere. The inversion develops at dusk and continues until the surface warms again the following day. Pollutants emitted during the night are caught under this i nversion lid. S ubsidence inversion forms when warm air masses move over colder air masses. The inversion develops with a stagnating high-pressure system (generally associated with fair weather). Under these conditions, the pressure gradient becomes progressively weaker so that winds become light. These light winds greatly reduce the horizontal transport and dispersion of pollutants. At the same time, the subsidence inversion acts as a barrier to the vertical dispersion of the pollutants. In this study, the Penn State/NCAR meso -scale model (MM5) is used to simulate the temperature inversion phenomenon over Greater Cairo region during the fall season of 2004. Accurate computations of the heat transfer at the surface are needed to capture this phenomenon. This can only be achieved by high-resolution simulations in both horizontal and vertical directions. Hence, for accurate simulation of the temperature inversion over Greater Cairo, four nested domains of resolutions of 27 km, 9 km, 3 km and 1 km, respectively, were used in the horizontal planes. Furthermore, 42

  17. Frequency domain performance analysis of nonlinearly controlled motion systems

    NARCIS (Netherlands)

    Pavlov, A.V.; Wouw, van de N.; Pogromski, A.Y.; Heertjes, M.F.; Nijmeijer, H.

    2007-01-01

    At the heart of the performance analysis of linear motion control systems lie essential frequency domain characteristics such as sensitivity and complementary sensitivity functions. For a class of nonlinear motion control systems called convergent systems, generalized versions of these sensitivity

  18. Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

    Directory of Open Access Journals (Sweden)

    A. Hodzic

    2007-08-01

    Full Text Available The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account a MODIS-derived daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are put into a radiative transfer model to estimate (off-line the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that the simulated wildfires generated comparable amounts of primary aerosol pollutants (130 kTons of PM2.5, fine particles to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of the smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August 2003 showed the ability of the model to reproduce high aerosol optical thickness (AOT over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Although there was a fairly good spatial agreement with satellite data (correlation coefficients ranging from 0.4 to 0.9, the temporal variability of AOT data at specific AERONET locations was not well captured by the model. Statistical analyses of model-simulated AOT data at AERONET ground stations showed a significant decrease in the model biases suggesting that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat

  19. Electrical Characteristics, Electrode Sheath and Contamination Layer Behavior of a Meso-Scale Premixed Methane-Air Flame Under AC/DC Electric Fields

    Science.gov (United States)

    Chen, Qi; Yan, Limin; Zhang, Hao; Li, Guoxiu

    2016-05-01

    Electrical characteristics of a nozzle-attached meso-scale premixed methane-air flame under low-frequency AC (0-4300 V, 0-500 Hz) and DC (0-3300 V) electric fields were studied. I-V curves were measured under different experimental conditions to estimate the magnitude of the total current 100-102 μA, the electron density 1015-1016 m-3 and further the power dissipation ≤ 0.7 W in the reaction zone. At the same time, the meso-scale premixed flame conductivity 10-4-10-3 Ω-1·m-1 as a function of voltage and frequency was experimentally obtained and was believed to represent a useful order-of magnitude estimate. Moreover, the influence of the collision sheath relating to Debye length (31-98 μm) and the contamination layer of an active electrode on measurements was discussed, based on the combination of simulation and theoretical analysis. As a result, the electrode sheath dimension was evaluated to less than 0.5 mm, which indicated a complex effect of the collision sheath on the current measurements. The surface contamination effect of an active electrode was further analyzed using the SEM imaging method, which showed elements immigration during the contamination layer formation process. supported by National Natural Science Foundation of China (No. 51376021), and the Fundamental Research Fund for Major Universities (No. 2013JBM079)

  20. Optical motion control of maglev graphite.

    Science.gov (United States)

    Kobayashi, Masayuki; Abe, Jiro

    2012-12-26

    Graphite has been known as a typical diamagnetic material and can be levitated in the strong magnetic field. Here we show that the magnetically levitating pyrolytic graphite can be moved in the arbitrary place by simple photoirradiation. It is notable that the optical motion control system described in this paper requires only NdFeB permanent magnets and light source. The optical movement is driven by photothermally induced changes in the magnetic susceptibility of the graphite. Moreover, we demonstrate that light energy can be converted into rotational kinetic energy by means of the photothermal property. We find that the levitating graphite disk rotates at over 200 rpm under the sunlight, making it possible to develop a new class of light energy conversion system.

  1. Universal CNC platform motion control technology for industrial CT

    International Nuclear Information System (INIS)

    Cheng Senlin; Wang Yang

    2011-01-01

    According to the more scanning methods and the higher speed of industrial CT, the higher precision of the motion location and the data collection sync-control is required at present, a new motion control technology was proposed, which was established based on the universal CNC system with high precision of multi-axis control. Aiming at the second and the third generation of CT scanning motion, a control method was researched, and achieved the demands of the changeable parameters and network control, Through the simulation of the second and the third generation of CT scanning motion process, the control precision of the rotation axis reached 0.001° and the linear axis reached 0.002 mm, Practical tests showed this system can meet the requirements of the multi-axis motion integration and the sync signal control, it also have advantages in the control precision and the performance. (authors)

  2. Revolution at SOLEIL: review and prospect for motion control

    International Nuclear Information System (INIS)

    Corruble, D.; Betinelli-Deck, P.; Blache, F.; Coquet, J.; Leclercq, N.; Millet, R.; Tournieux, A.

    2012-01-01

    At any synchrotron facility, motors are numerous: they are the significant actuators of accelerators and the main actuators of beamlines. Since 2003, the Electronic Control and data Acquisition group at SOLEIL has defined a modular and reliable motion architecture integrating industrial products (Galil controller, Midi-Engineering and Phytron power boards). Simultaneously, the software control group has developed a set of dedicated Tango devices. At present, more than 1000 motors and 200 motion controller crates are in operation at SOLEIL. Aware that motion control is important in improving performance, given that the positioning of optical systems and samples is a key element of any beamline, SOLEIL wants to upgrade its motion controller in order to maintain the facility at a high performance level and be able to respond to new requirements: better accuracy, complex trajectory and coupling multi-axis devices such as hexa-pods. This project is called REVOLUTION (Reconsider Various controllers for your motion). (authors)

  3. Utilizing the meso-scale grain boundary stress to estimate the onset of delamination in 2099-T861 aluminium–lithium

    International Nuclear Information System (INIS)

    McDonald, Russell J; Beaudoin, Armand J

    2010-01-01

    Aluminium–lithium alloys provide a lower density and higher stiffness alternative to other high strength aluminium alloys. However, many Al–Li alloys exhibit a non-traditional failure mechanism called delamination, which refers to the failure of the elongated grain boundary interface. In this investigation, delaminations were observed after cyclic deformation of both uniaxial and torsion experiments. A cyclically stable rate-independent crystal plasticity framework with kinematic hardening was developed to address many experimental trends of stabilized cyclic plasticity. Utilizing this framework, meso-scale grain boundary interface stresses were estimated with uniform deformation and bi-crystal models. These models are computationally amenable to investigate both orientation dependence and the statistical nature of the grain boundary stresses for a given bulk texture and nominal loading. A coupled shear-normal Findley-based damage parameter was formulated to quantitatively characterize the nucleation of delamination consistently with experimental trends

  4. Regionalization of meso-scale physically based nitrogen modeling outputs to the macro-scale by the use of regression trees

    Science.gov (United States)

    Künne, A.; Fink, M.; Kipka, H.; Krause, P.; Flügel, W.-A.

    2012-06-01

    In this paper, a method is presented to estimate excess nitrogen on large scales considering single field processes. The approach was implemented by using the physically based model J2000-S to simulate the nitrogen balance as well as the hydrological dynamics within meso-scale test catchments. The model input data, the parameterization, the results and a detailed system understanding were used to generate the regression tree models with GUIDE (Loh, 2002). For each landscape type in the federal state of Thuringia a regression tree was calibrated and validated using the model data and results of excess nitrogen from the test catchments. Hydrological parameters such as precipitation and evapotranspiration were also used to predict excess nitrogen by the regression tree model. Hence they had to be calculated and regionalized as well for the state of Thuringia. Here the model J2000g was used to simulate the water balance on the macro scale. With the regression trees the excess nitrogen was regionalized for each landscape type of Thuringia. The approach allows calculating the potential nitrogen input into the streams of the drainage area. The results show that the applied methodology was able to transfer the detailed model results of the meso-scale catchments to the entire state of Thuringia by low computing time without losing the detailed knowledge from the nitrogen transport modeling. This was validated with modeling results from Fink (2004) in a catchment lying in the regionalization area. The regionalized and modeled excess nitrogen correspond with 94%. The study was conducted within the framework of a project in collaboration with the Thuringian Environmental Ministry, whose overall aim was to assess the effect of agro-environmental measures regarding load reduction in the water bodies of Thuringia to fulfill the requirements of the European Water Framework Directive (Bäse et al., 2007; Fink, 2006; Fink et al., 2007).

  5. Motion control, motion sickness, and the postural dynamics of mobile devices.

    Science.gov (United States)

    Stoffregen, Thomas A; Chen, Yi-Chou; Koslucher, Frank C

    2014-04-01

    Drivers are less likely than passengers to experience motion sickness, an effect that is important for any theoretical account of motion sickness etiology. We asked whether different types of control would affect the incidence of motion sickness, and whether any such effects would be related to participants' control of their own bodies. Participants played a video game on a tablet computer. In the Touch condition, the device was stationary and participants controlled the game exclusively through fingertip inputs via the device's touch screen. In the Tilt condition, participants held the device in their hands and moved the device to control some game functions. Results revealed that the incidence of motion sickness was greater in the Touch condition than in the Tilt condition. During game play, movement of the head and torso differed as a function of the type of game control. Before the onset of subjective symptoms of motion sickness, movement of the head and torso differed between participants who later reported motion sickness and those that did not. We discuss implications of these results for theories of motion sickness etiology.

  6. Design and analysis of a rotary motion controller

    Directory of Open Access Journals (Sweden)

    Julio Cesar Caye

    2015-12-01

    Full Text Available This paper presents the design of a rotary motion controller based on the peritrochoid geometry of the rotary (Wankle engine. It uses an orifice limited flow of incompressible fluid between the chambers of the Wankle-type geometry to control the rotation of the rotor. The paper develops the theory of operation and then implements the design as a Matlab model to simulate the motion control under various conditions. It is found that the time to reach stabilised motion is determined by the orifice size and fluid density. When stabilised motion is achieved, the motion dependence on material and geometry factors is determined by the orifice flow equation. The angular velocity is also found to have a square root dependence on the applied torque when in the stabilised regime.

  7. Low-latency wireless data transfer for motion control

    NARCIS (Netherlands)

    Boeij, de J.; Haazen, M.H.; Smulders, P.F.M.; Lomonova, E.A.

    2009-01-01

    This paper discusses a new approach for wireless motion control. Existing wireless techniques suffer from large closed loop delays of several milliseconds, which is unacceptable in precision motion systems. These large delays are mainly caused by the protocol used, since these are optimized for

  8. Stable carbon and nitrogen isotope variation in the northern lampfish and Neocalanus, marine survival rates of pink salmon, and meso-scale eddies in the Gulf of Alaska

    Science.gov (United States)

    Kline, Thomas C., Jr.

    2010-10-01

    Northern lampfish (NLF), Stenobrachius leucopsarus (Myctophidae), the dominant pelagic fish taxon of the subarctic North Pacific Ocean, were sampled opportunistically in MOCNESS tows made on continental slope waters of the Gulf of Alaska (GOA) as well as in deep areas of Prince William Sound (PWS) during 1997-2006. The overall mean whole-body lipid-corrected stable carbon isotope value of NLF from the GOA was -21.4 (SD = 0.7) whereas that from PWS was -19.5 (SD = 0.9). This pattern is similar to that observed for late feeding stage Neocalanus cristatus copepods thus confirming a mean cross-shelf carbon stable isotope gradient. As well, there was a statistically significant positive correlation between the considerable temporal variation in the monthly mean carbon stable isotope composition of GOA Neocalanus and GOA NLF ( r = 0.69, P food chain length whereas carbon stable isotopes reflect organic carbon production. The carbon stable isotope values of NLF, measured in May, were positively correlated to marine survival rate of PWS hatchery salmon cohorts entering the marine environment the same year ( r = 0.84, P < 0.001). The carbon stable isotope values for Neocalanus in May were also positively correlated to salmon marine survival ( r = 0.82, P < 0.001). Processes thus manifested through the carbon stable isotope value of biota from the continental slope more closely predicted marine survival rate than that of the salmon themselves. The incipient relationships suggested by the correlations are consistent with the hypothesis that exchange between coastal and oceanic waters in the study area is driven by meso-scale eddies. These eddies facilitate the occurrence of slope phytoplankton blooms as well as drive oceanic zooplankton subsidies into coastal waters. The strong as well as more significant correlations of salmon marine survival rate to NLF as well as slope Neocalanus carbon stable isotope values point to processes taking place at the slope (i.e., interactions

  9. Motion control of servo cylinder using neural network

    International Nuclear Information System (INIS)

    Hwang, Un Kyoo; Cho, Seung Ho

    2004-01-01

    In this paper, a neural network controller that can be implemented in parallel with a PD controller is suggested for motion control of a hydraulic servo cylinder. By applying a self-excited oscillation method, the system design parameters of open loop transfer function of servo cylinder system are identified. Based on system design parameters, the PD gains are determined for the desired closed loop characteristics. The neural network is incorporated with PD control in order to compensate the inherent nonlinearities of hydraulic servo system. As an application example, a motion control using PD-NN has been performed and proved its superior performance by comparing with that of a PD control

  10. Atto-second control of collective electron motion in plasmas

    International Nuclear Information System (INIS)

    Borot, Antonin; Malvache, Arnaud; Chen, Xiaowei; Jullien, Aurelie; Lopez-Martens, Rodrigo; Geindre, Jean-Paul; Audebert, Patrick; Mourou, Gerard; Quere, Fabien

    2012-01-01

    Today, light fields of controlled and measured waveform can be used to guide electron motion in atoms and molecules with atto-second precision. Here, we demonstrate atto-second control of collective electron motion in plasmas driven by extreme intensity (approximate to 10 18 W cm -2 ) light fields. Controlled few-cycle near-infrared waves are tightly focused at the interface between vacuum and a solid-density plasma, where they launch and guide sub-cycle motion of electrons from the plasma with characteristic energies in the multi-kilo-electron-volt range-two orders of magnitude more than has been achieved so far in atoms and molecules. The basic spectroscopy of the coherent extreme ultraviolet radiation emerging from the light-plasma interaction allows us to probe this collective motion of charge with sub-200 as resolution. This is an important step towards atto-second control of charge dynamics in laser-driven plasma experiments. (authors)

  11. Leap Motion controller application in augmented reality technology

    OpenAIRE

    Artemčiukas, Edgaras; Sakalauskas, Leonidas

    2014-01-01

    In this work the analysis of interaction techniques, devices and its’ possibilities were accomplished. It was determined that the problem, which many researchers tries to solve – more natural interaction between users and computers. Interaction system in augmented reality environment using Leap Motion controller was developed. To achieve this goal augmented reality NyARToolkit and Leap Motion controller libraries were used. Solution ensures extensive information about hand, finger...

  12. Hierarchical Motion Control for a Team of Humanoid Soccer Robots

    Directory of Open Access Journals (Sweden)

    Seung-Joon Yi

    2016-02-01

    Full Text Available Robot soccer has become an effective benchmarking problem for robotics research as it requires many aspects of robotics including perception, self localization, motion planning and distributed coordination to work in uncertain and adversarial environments. Especially with humanoid robots that lack inherent stability, a capable and robust motion controller is crucial for generating walking and kicking motions without losing balance. In this paper, we describe the details of a motion controller to control a team of humanoid soccer robots, which consists of a hierarchy of controllers with different time frames and abstraction levels. A low level controller governs the real time control of each joint angle, either using target joint angles or target endpoint transforms. A mid-level controller handles bipedal locomotion and balancing of the robot. A high level controller decides the long term behavior of the robot, and finally the team level controller coordinates the behavior of a group of robots by means of asynchronous communication between the robots. The suggested motion system has been successfully used by many humanoid robot teams at the RoboCup international robot soccer competitions, which has awarded us five successful championships in a row.

  13. Simulation of Wind-Driven Snow Redistribution at a High-Elevation Alpine Site Using a Meso-Scale Atmospheric Model

    Science.gov (United States)

    Vionnet, V.; Martin, E.; Masson, V.; Guyomarc'h, G.; Naaim-Bouvet, F.; Prokop, A.; Durand, Y.; Lac, C.

    2012-12-01

    In alpine regions, blowing snow events strongly influence the temporal and spatial evolution of the snow depth distribution throughout the winter season. We recently developed a new simulation system to gain understanding on the complex processes that drive the redistribution of snow by the wind in complex terrain. This new system couples directly the detailed snow-pack model Crocus with the meso-scale atmospheric model Meso-NH. A blowing snow scheme allows Meso-NH to simulate the transport of snow particles in the atmosphere. We used the coupled system to study a blowing snow event with snowfall that occurred in February 2011 in the Grandes Rousses range (French Alps). Three nested domains at an horizontal resolution of 450, 150 and 50 m allow the model to simulate the complex 3D precipitation and wind fields around our experimental site (2720 m a.s.l.) during this 22-hour event. Wind-induced snow transport is activated over the domains of higher resolution (150 and 50 m). We firstly assessed the ability of the model to reproduce atmospheric flows at high resolution in alpine terrain using a large dataset of observations (meteorological data, vertical profile of wind speed). Simulated blowing snow fluxes are then compared with measurements from SPC and mechanical snow traps. Finally a map of snow erosion and accumulation produced by Terrestrial Laser measurements allows to evaluate the quality of the simulated snow depth redistribution.

  14. PID motion control tuning rules in a damping injection framework

    NARCIS (Netherlands)

    Tadele, T.S.; de Vries, Theodorus J.A.; Stramigioli, Stefano

    2013-01-01

    This paper presents a general design approach for a performance based tuning of a damping injection framework impedance controller by using insights from PID motion control tuning rules. The damping injection framework impedance controller is suitable for human friendly robots as it enhances safety

  15. Sensing human hand motions for controlling dexterous robots

    Science.gov (United States)

    Marcus, Beth A.; Churchill, Philip J.; Little, Arthur D.

    1988-01-01

    The Dexterous Hand Master (DHM) system is designed to control dexterous robot hands such as the UTAH/MIT and Stanford/JPL hands. It is the first commercially available device which makes it possible to accurately and confortably track the complex motion of the human finger joints. The DHM is adaptable to a wide variety of human hand sizes and shapes, throughout their full range of motion.

  16. Spatial design and control of graphene flake motion

    Science.gov (United States)

    Ghorbanfekr-Kalashami, H.; Peeters, F. M.; Novoselov, K. S.; Neek-Amal, M.

    2017-08-01

    The force between a sharp scanning probe tip and a surface can drive a graphene flake over crystalline substrates. The recent design of particular patterns of structural defects on a graphene surface allows us to propose an alternative approach for controlling the motion of a graphene flake over a graphene substrate. The thermally induced motion of a graphene flake is controlled by engineering topological defects in the substrate. Such defect regions lead to an inhomogeneous energy landscape and are energetically unfavorable for the motion of the flake, and will invert and scatter graphene flakes when they are moving toward the defect line. Engineering the distribution of these energy barriers results in a controllable trajectory for the thermal motion of the flake without using any external force. We predict superlubricity of the graphene flake for motion along and between particular defect lines. This Rapid Communication provides insights into the frictional forces of interfaces and opens a route to the engineering of the stochastic motion of a graphene flake over any crystalline substrate.

  17. Bandwidth-on-demand motion control

    NARCIS (Netherlands)

    Van Loon, S.J.L.M.; Hunnekens, B.G.B.; Simon, A.S.; van de Wouw, N.; Heemels, W.P.M.H.

    2018-01-01

    In this brief, we introduce a 'bandwidth-on-demand' variable-gain control (VGC) strategy that allows for a varying bandwidth of the feedback controller. The proposed VGC can achieve improved performance given time-varying, reference-dependent performance requirements compared with linear

  18. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2000-01-01

    for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation force......The objective of this paper is to develop a control scheme for stabilization of a hamiltonian system. The method generalizes the results available in the literature on motion control in the Euclidean space to an arbitrary differrential manifol equipped with a metric. This modification is essencial...... on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...

  19. Stabilization of rotational motion with application to spacecraft attitude control

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2001-01-01

    for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation force......The objective of this paper is to develop a control scheme for stabilization of a hamiltonian system. The method generalizes the results available in the literature on motion control in the Euclidean space to an arbitrary differrential manifol equipped with a metric. This modification is essencial...... on a Riemannian manifold. The Lyapnov stability theory is adapted and reformulated to fit to the new framework of Riemannian manifolds. Toillustrate the results a spacecraft attitude control problem is considered. Firstly, a global canonical representation for the spacecraft motion is found, then three spacecraft...

  20. High-speed precision motion control

    CERN Document Server

    Yamaguchi, Takashi; Pang, Chee Khiang

    2011-01-01

    Written for researchers and postgraduate students in Control Engineering, as well as professionals in the Hard Disk Drive industry, this book discusses high-precision and fast servo controls in Hard Disk Drives (HDDs). The editors present a number of control algorithms that enable fast seeking and high precision positioning, and propose problems from commercial products, making the book valuable to researchers in HDDs. Each chapter is self contained, and progresses from concept to technique, present application examples that can be used within automotive, aerospace, aeronautical, and manufactu

  1. BWR ATWS mitigation by Fine Motion Control Rod

    International Nuclear Information System (INIS)

    Rohatgi, U.S.; Cheng, H.S.; Khan, H.; Mallen, A.; Diamond, D.

    1994-01-01

    Two main methods of ATWS mitigation in a SBWR are: fine Motion control Rods (FMCRD) and Boron injection via the Standby Liquid control System (SLCS). This study has demonstrated that the use of FMCRD along with feedwater runback mitigated the conditions due to reactivity insertion and possible ATWS in a BWR which is similar to SBWR

  2. Infrared wireless data transfer for real-time motion control

    NARCIS (Netherlands)

    Gajdusek, M.; Overboom, T.T.; Damen, A.A.H.; Bosch, van den P.P.J.

    2009-01-01

    In this paper several wireless solution are compared for their suitability for real-time control of a fast motion system. From the comparison, Very Fast Infrared (VFIR) communication link has been found to be an attractive solution for presented wirelessly controlled manipulator. Because standard

  3. Analytical one parameter method for PID motion controller settings

    NARCIS (Netherlands)

    van Dijk, Johannes; Aarts, Ronald G.K.M.

    2012-01-01

    In this paper analytical expressions for PID-controllers settings for electromechanical motion systems are presented. It will be shown that by an adequate frequency domain oriented parametrization, the parameters of a PID-controller are analytically dependent on one variable only, the cross-over

  4. New human-centered linear and nonlinear motion cueing algorithms for control of simulator motion systems

    Science.gov (United States)

    Telban, Robert J.

    While the performance of flight simulator motion system hardware has advanced substantially, the development of the motion cueing algorithm, the software that transforms simulated aircraft dynamics into realizable motion commands, has not kept pace. To address this, new human-centered motion cueing algorithms were developed. A revised "optimal algorithm" uses time-invariant filters developed by optimal control, incorporating human vestibular system models. The "nonlinear algorithm" is a novel approach that is also formulated by optimal control, but can also be updated in real time. It incorporates a new integrated visual-vestibular perception model that includes both visual and vestibular sensation and the interaction between the stimuli. A time-varying control law requires the matrix Riccati equation to be solved in real time by a neurocomputing approach. Preliminary pilot testing resulted in the optimal algorithm incorporating a new otolith model, producing improved motion cues. The nonlinear algorithm vertical mode produced a motion cue with a time-varying washout, sustaining small cues for longer durations and washing out large cues more quickly compared to the optimal algorithm. The inclusion of the integrated perception model improved the responses to longitudinal and lateral cues. False cues observed with the NASA adaptive algorithm were absent. As a result of unsatisfactory sensation, an augmented turbulence cue was added to the vertical mode for both the optimal and nonlinear algorithms. The relative effectiveness of the algorithms, in simulating aircraft maneuvers, was assessed with an eleven-subject piloted performance test conducted on the NASA Langley Visual Motion Simulator (VMS). Two methods, the quasi-objective NASA Task Load Index (TLX), and power spectral density analysis of pilot control, were used to assess pilot workload. TLX analysis reveals, in most cases, less workload and variation among pilots with the nonlinear algorithm. Control input

  5. Efficient control of mechatronic systems in dynamic motion tasks

    Directory of Open Access Journals (Sweden)

    Despotova Desislava

    2018-01-01

    Full Text Available Robots and powered exoskeletons have often complex and non-linear dynamics due to friction, elasticity, and changing load. The proposed study addresses various-type robots that have to perform dynamic point-to-point motion tasks (PTPMT. The performance demands are for faster motion, higher positioning accuracy, and lower energy consumption. With given motion task, it is of primary importance to study the structure and controllability of the corresponding controlled system. The following natural decentralized controllability condition is assumed: the signs of any control input and the corresponding output (the acceleration are the same, at least when the control input is at its maximum absolute value. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Further on, we propose a generic optimisation approach for control learning synthesis of various type robotic systems in PTPMT. Our procedure for iterative learning control (LC has the following main steps: (1 choose a set of appropriate test control functions; (2 define the most relevant input-output pairs; and (3 solve shooting equations and perform control parameter optimisation. We will give several examples to explain our controllability and optimisation concepts.

  6. Evaluation of high intensity precipitation from 16 Regional climate models over a meso-scale catchment in the Midlands Regions of England

    Science.gov (United States)

    Wetterhall, F.; He, Y.; Cloke, H.; Pappenberger, F.; Freer, J.; Wilson, M.; McGregor, G.

    2009-04-01

    Local flooding events are often triggered by high-intensity rain-fall events, and it is important that these can be correctly modelled by Regional Climate Models (RCMs) if the results are to be used in climate impact assessment. In this study, daily precipitation from 16 RCMs was compared with observations over a meso-scale catchment in the Midlands Region of England. The RCM data was provided from the European research project ENSEMBLES and the precipitation data from the UK MetOffice. The RCMs were all driven by reanalysis data from the ERA40 dataset over the time period 1961-2000. The ENSEMBLES data is on the spatial scale of 25 x 25 km and it was disaggregated onto a 5 x 5 km grid over the catchment and compared with interpolated observational data with the same resolution. The mean precipitation was generally underestimated by the ENSEMBLES data, and the maximum and persistence of high intensity rainfall was even more underestimated. The inter-annual variability was not fully captured by the RCMs, and there was a systematic underestimation of precipitation during the autumn months. The spatial pattern in the modelled precipitation data was too smooth in comparison with the observed data, especially in the high altitudes in the western part of the catchment where the high precipitation usually occurs. The RCM outputs cannot reproduce the current high intensity precipitation events that are needed to sufficiently model extreme flood events. The results point out the discrepancy between climate model output and the high intensity precipitation input needs for hydrological impact modelling.

  7. Combined influence of meso-scale circulation and bathymetry on the foraging behaviour of a diving predator, the king penguin (Aptenodytes patagonicus)

    Science.gov (United States)

    Scheffer, Annette; Trathan, Philip N.; Edmonston, Johnnie G.; Bost, Charles-André

    2016-02-01

    Investigating the responses of marine predators to environmental features is of key importance for understanding their foraging behaviour and reproductive success. In this study we examined the foraging behaviour of king penguins breeding at Kerguelen (southern Indian Ocean) in relation to oceanographic and bathymetric features within their foraging ambit. We used ARGOS and Global Positioning System tracking together with Time-Depth-Temperature-Recorders (TDR) to follow the at-sea movements of incubating and brooding king penguins. Combining the penguin behaviour with oceanographic data at the surface through satellite data and at depth through in-situ recordings by the TDRs enabled us to explore how these predators adjusted their horizontal and vertical foraging movements in response to their physical environment. Relating the observed behaviour and oceanographic patterns to local bathymetry lead to a comprehensive picture of the combined influence of bathymetry and meso-scale circulation on the foraging behaviour of king penguins. During both breeding stages king penguins foraged in the area to the south-east of Kerguelen, where they explored an influx of cold waters of southern origin interacting with the Kerguelen Plateau bathymetry. Foraging in the Polar Front and at the thermocline was associated with high prey capture rates. However, foraging trip orientation and water mass utilization suggested that bathymetrically entrained cold-water features provided the most favourable foraging locations. Our study explicitly reports the exploration of bathymetry-related oceanographic features by foraging king penguins. It confirms the presence of Areas of Ecological Significance for marine predators on the Kerguelen Plateau, and suggests the importance of further areas related to the cold-water flow along the shelf break of the Kerguelen Plateau.

  8. Application and comparison of the SCS-CN-based rainfall-runoff model in meso-scale watershed and field scale

    Science.gov (United States)

    Luo, L.; Wang, Z.

    2010-12-01

    Soil Conservation Service Curve Number (SCS-CN) based hydrologic model, has widely been used for agricultural watersheds in recent years. However, there will be relative error when applying it due to differentiation of geographical and climatological conditions. This paper introduces a more adaptable and propagable model based on the modified SCS-CN method, which specializes into two different scale cases of research regions. Combining the typical conditions of the Zhanghe irrigation district in southern part of China, such as hydrometeorologic conditions and surface conditions, SCS-CN based models were established. The Xinbu-Qiao River basin (area =1207 km2) and the Tuanlin runoff test area (area =2.87 km2)were taken as the study areas of basin scale and field scale in Zhanghe irrigation district. Applications were extended from ordinary meso-scale watershed to field scale in Zhanghe paddy field-dominated irrigated . Based on actual measurement data of land use, soil classification, hydrology and meteorology, quantitative evaluation and modifications for two coefficients, i.e. preceding loss and runoff curve, were proposed with corresponding models, table of CN values for different landuse and AMC(antecedent moisture condition) grading standard fitting for research cases were proposed. The simulation precision was increased by putting forward a 12h unit hydrograph of the field area, and 12h unit hydrograph were simplified. Comparison between different scales show that it’s more effectively to use SCS-CN model on field scale after parameters calibrated in basin scale These results can help discovering the rainfall-runoff rule in the district. Differences of established SCS-CN model's parameters between the two study regions are also considered. Varied forms of landuse and impacts of human activities were the important factors which can impact the rainfall-runoff relations in Zhanghe irrigation district.

  9. High-frequency and meso-scale winter sea-ice variability in the Southern Ocean in a high-resolution global ocean model

    Science.gov (United States)

    Stössel, Achim; von Storch, Jin-Song; Notz, Dirk; Haak, Helmuth; Gerdes, Rüdiger

    2018-03-01

    This study is on high-frequency temporal variability (HFV) and meso-scale spatial variability (MSV) of winter sea-ice drift in the Southern Ocean simulated with a global high-resolution (0.1°) sea ice-ocean model. Hourly model output is used to distinguish MSV characteristics via patterns of mean kinetic energy (MKE) and turbulent kinetic energy (TKE) of ice drift, surface currents, and wind stress, and HFV characteristics via time series of raw variables and correlations. We find that (1) along the ice edge, the MSV of ice drift coincides with that of surface currents, in particular such due to ocean eddies; (2) along the coast, the MKE of ice drift is substantially larger than its TKE and coincides with the MKE of wind stress; (3) in the interior of the ice pack, the TKE of ice drift is larger than its MKE, mostly following the TKE pattern of wind stress; (4) the HFV of ice drift is dominated by weather events, and, in the absence of tidal currents, locally and to a much smaller degree by inertial oscillations; (5) along the ice edge, the curl of the ice drift is highly correlated with that of surface currents, mostly reflecting the impact of ocean eddies. Where ocean eddies occur and the ice is relatively thin, ice velocity is characterized by enhanced relative vorticity, largely matching that of surface currents. Along the ice edge, ocean eddies produce distinct ice filaments, the realism of which is largely confirmed by high-resolution satellite passive-microwave data.

  10. Meso-scale on-road vehicle emission inventory approach: a study on Dhaka City of Bangladesh supporting the 'cause-effect' analysis of the transport system.

    Science.gov (United States)

    Iqbal, Asif; Allan, Andrew; Zito, Rocco

    2016-03-01

    The study aims to develop an emission inventory (EI) approach and conduct an inventory for vehicular sources in Dhaka City, Bangladesh. A meso-scale modelling approach was adopted for the inventory; the factors that influence the emissions and the magnitude of emission variation were identified and reported on, which was an innovative approach to account emissions unlike the conventional inventory approaches. Two techniques for the emission inventory were applied, viz. (i) a combined top-down and bottom-up approach that considered the total vehicle population and the average diurnal on-road vehicle speed profile in the city and (ii) a bottom-up approach that accounted for road link-specific emissions of the city considering diurnal traffic volume and speed profiles of the respective roads. For the bottom-up approach, road link-specific detailed data were obtained through field survey in 2012, where mid-block traffic count of the day, vehicle speed profile, road network and congestion data were collected principally. The emission variances for the change in transport system characteristics (like change in fuel type, AC usage pattern, increased speed and reduced congestion/stopping) were predicted and analysed in this study; congestion influenced average speed of the vehicles, and fuel types in the vehicles were identified as the major stressors. The study performance was considered reasonable when comparing with the limited number of similar studies conducted earlier. Given the increasing trend of private vehicles each year coupled with increasing traffic congestion, the city is under threat of increased vehicular emissions unless a good management strategy is implemented. Although the inventory is conducted for Dhaka and the result may be important locally, the approach adopted in this research is innovative in nature to be followed for conducting research on other urban transport systems.

  11. Development of excavator training simulator using leap motion controller

    Science.gov (United States)

    Fahmi, F.; Nainggolan, F.; Andayani, U.; Siregar, B.

    2018-03-01

    Excavator is a heavy machinery that is used for many industries purposes. Controlling the excavator is not easy. Its operator has to be trained well in many skills to make sure it is safe, effective, and efficient while using the excavator. In this research, we proposed a virtual reality excavator simulator supported by a device called Leap Motion Controller that supports finger and hand motions as an input. This prototype will be developed than in the virtual reality environment to give a more real sensing to the user.

  12. Dynamics and control of Lorentz-augmented spacecraft relative motion

    CERN Document Server

    Yan, Ye; Yang, Yueneng

    2017-01-01

    This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.

  13. IT-tool Concept for Design and Intelligent Motion Control

    DEFF Research Database (Denmark)

    Conrad, Finn; Hansen, Poul Erik; Sørensen, Torben

    2000-01-01

    The paper presents results obtained from a Danish mechatronic research program focusing on intelligent motion control as well as results from the Esprit project SWING on IT-tools for rapid prototyping of fluid power components and systems. A mechatronic test facility with digital controllers for ....... Furthermore, a developed IT-tool concept for controller and system design utilising the ISO 10303 STEP Standard is proposed....

  14. Leap Motion Device Used to Control a Real Anthropomorphic Gripper

    Directory of Open Access Journals (Sweden)

    Ionel Staretu

    2016-06-01

    Full Text Available This paper presents for the first time the use of the Leap Motion device to control an anthropomorphic gripper with five fingers. First, a description of the Leap Motion device is presented, highlighting its main functional characteristics, followed by testing of its use for capturing the movements of a human hand's fingers in different configurations. Next, the HandCommander soft module and the Interface Controller application are described. The HandCommander is a software module created to facilitate interaction between a human hand and the GraspIT virtual environment, and the Interface Controller application is required to send motion data to the virtual environment and to test the communication protocol. For the test, a prototype of an anthropomorphic gripper with five fingers was made, including a proper hardware system of command and control, which is briefly presented in this paper. Following the creation of the prototype, the command system performance test was conducted under real conditions, evaluating the recognition efficiency of the objects to be gripped and the efficiency of the command and control strategies for the gripping process. The gripping test is exemplified by the gripping of an object, such as a screw spanner. It was found that the command system, both in terms of capturing human hand gestures with the Leap Motion device and effective object gripping, is operational. Suggestive figures are presented as examples.

  15. Analysis of Offshore Knuckle Boom Crane - Part Two: Motion Control

    Directory of Open Access Journals (Sweden)

    Morten K. Bak

    2013-10-01

    Full Text Available In this paper design of electro-hydraulic motion control systems for offshore knuckle boom cranes is discussed. The influence of the control valve bandwidth along with the ramp time for the control signal are investigated both analytically with simplified system models and numerically with an experimentally verified crane model. The results of both types of investigations are related to general design rules for selection of control valves and ramp times and the relevance of these design rules is discussed. Generally, they are useful but may be too conservative for offshore knuckle boom cranes. However, as demonstrated in the paper, the only proper way to determine this is to evaluate the motion control system design by means of simulation.

  16. Two-pulse laser control of nuclear and electronic motion

    DEFF Research Database (Denmark)

    Grønager, Michael; Henriksen, Niels Engholm

    1997-01-01

    We discuss an explicitly time-dependent two-pulse laser scheme for controlling where nuclei and electrons are going in unimolecular reactions. We focus on electronic motion and show, with HD+ as an example, that one can find non-stationary states where the electron (with some probability...

  17. Vision based motion control for a humanoid head

    NARCIS (Netherlands)

    Visser, L.C.; Carloni, Raffaella; Stramigioli, Stefano

    2009-01-01

    This paper describes the design of a motion control algorithm for a humanoid robotic head, which consists of a neck with four degrees of freedom and two eyes (a stereo pair system) that tilt on a common axis and rotate sideways freely. The kinematic and dynamic properties of the head are analyzed

  18. Validation of the Leap Motion Controller using markered motion capture technology.

    Science.gov (United States)

    Smeragliuolo, Anna H; Hill, N Jeremy; Disla, Luis; Putrino, David

    2016-06-14

    The Leap Motion Controller (LMC) is a low-cost, markerless motion capture device that tracks hand, wrist and forearm position. Integration of this technology into healthcare applications has begun to occur rapidly, making validation of the LMC׳s data output an important research goal. Here, we perform a detailed evaluation of the kinematic data output from the LMC, and validate this output against gold-standard, markered motion capture technology. We instructed subjects to perform three clinically-relevant wrist (flexion/extension, radial/ulnar deviation) and forearm (pronation/supination) movements. The movements were simultaneously tracked using both the LMC and a marker-based motion capture system from Motion Analysis Corporation (MAC). Adjusting for known inconsistencies in the LMC sampling frequency, we compared simultaneously acquired LMC and MAC data by performing Pearson׳s correlation (r) and root mean square error (RMSE). Wrist flexion/extension and radial/ulnar deviation showed good overall agreement (r=0.95; RMSE=11.6°, and r=0.92; RMSE=12.4°, respectively) with the MAC system. However, when tracking forearm pronation/supination, there were serious inconsistencies in reported joint angles (r=0.79; RMSE=38.4°). Hand posture significantly influenced the quality of wrist deviation (P<0.005) and forearm supination/pronation (P<0.001), but not wrist flexion/extension (P=0.29). We conclude that the LMC is capable of providing data that are clinically meaningful for wrist flexion/extension, and perhaps wrist deviation. It cannot yet return clinically meaningful data for measuring forearm pronation/supination. Future studies should continue to validate the LMC as updated versions of their software are developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Research on NC motion controller based on SOPC technology

    Science.gov (United States)

    Jiang, Tingbiao; Meng, Biao

    2006-11-01

    With the rapid development of the digitization and informationization, the application of numerical control technology in the manufacturing industry becomes more and more important. However, the conventional numerical control system usually has some shortcomings such as the poor in system openness, character of real-time, cutability and reconfiguration. In order to solve these problems, this paper investigates the development prospect and advantage of the application in numerical control area with system-on-a-Programmable-Chip (SOPC) technology, and puts forward to a research program approach to the NC controller based on SOPC technology. Utilizing the characteristic of SOPC technology, we integrate high density logic device FPGA, memory SRAM, and embedded processor ARM into a single programmable logic device. We also combine the 32-bit RISC processor with high computing capability of the complicated algorithm with the FPGA device with strong motivable reconfiguration logic control ability. With these steps, we can greatly resolve the defect described in above existing numerical control systems. For the concrete implementation method, we use FPGA chip embedded with ARM hard nuclear processor to construct the control core of the motion controller. We also design the peripheral circuit of the controller according to the requirements of actual control functions, transplant real-time operating system into ARM, design the driver of the peripheral assisted chip, develop the application program to control and configuration of FPGA, design IP core of logic algorithm for various NC motion control to configured it into FPGA. The whole control system uses the concept of modular and structured design to develop hardware and software system. Thus the NC motion controller with the advantage of easily tailoring, highly opening, reconfigurable, and expandable can be implemented.

  20. Motion Control of Urea-Powered Biocompatible Hollow Microcapsules.

    Science.gov (United States)

    Ma, Xing; Wang, Xu; Hahn, Kersten; Sánchez, Samuel

    2016-03-22

    The quest for biocompatible microswimmers powered by compatible fuel and with full motion control over their self-propulsion is a long-standing challenge in the field of active matter and microrobotics. Here, we present an active hybrid microcapsule motor based on Janus hollow mesoporous silica microparticles powered by the biocatalytic decomposition of urea at physiological concentrations. The directional self-propelled motion lasts longer than 10 min with an average velocity of up to 5 body lengths per second. Additionally, we control the velocity of the micromotor by chemically inhibiting and reactivating the enzymatic activity of urease. The incorporation of magnetic material within the Janus structure provides remote magnetic control on the movement direction. Furthermore, the mesoporous/hollow structure can load both small molecules and larger particles up to hundreds of nanometers, making the hybrid micromotor an active and controllable drug delivery microsystem.

  1. FPGA Implementation of Real-Time Ethernet for Motion Control

    Directory of Open Access Journals (Sweden)

    Chen Youdong

    2013-01-01

    Full Text Available This paper provides an applicable implementation of real-time Ethernet named CASNET, which modifies the Ethernet medium access control (MAC to achieve the real-time requirement for motion control. CASNET is the communication protocol used for motion control system. Verilog hardware description language (VHDL has been used in the MAC logic design. The designed MAC serves as one of the intellectual properties (IPs and is applicable to various industrial controllers. The interface of the physical layer is RJ45. The other layers have been implemented by using C programs. The real-time Ethernet has been implemented by using field programmable gate array (FPGA technology and the proposed solution has been tested through the cycle time, synchronization accuracy, and Wireshark testing.

  2. Repetitive motion planning and control of redundant robot manipulators

    CERN Document Server

    Zhang, Yunong

    2013-01-01

    Repetitive Motion Planning and Control of Redundant Robot Manipulators presents four typical motion planning schemes based on optimization techniques, including the fundamental RMP scheme and its extensions. These schemes are unified as quadratic programs (QPs), which are solved by neural networks or numerical algorithms. The RMP schemes are demonstrated effectively by the simulation results based on various robotic models; the experiments applying the fundamental RMP scheme to a physical robot manipulator are also presented. As the schemes and the corresponding solvers presented in the book have solved the non-repetitive motion problems existing in redundant robot manipulators, it is of particular use in applying theoretical research based on the quadratic program for redundant robot manipulators in industrial situations. This book will be a valuable reference work for engineers, researchers, advanced undergraduate and graduate students in robotics fields. Yunong Zhang is a professor at The School of Informa...

  3. Manipulation and controlled amplification of Brownian motion of microcantilever sensors

    International Nuclear Information System (INIS)

    Mehta, Adosh; Cherian, Suman; Hedden, David; Thundat, Thomas

    2001-01-01

    Microcantilevers, such as those used in atomic force microscopy, undergo Brownian motion due to mechanical thermal noise. The root mean square amplitude of the Brownian motion of a cantilever typically ranges from 0.01--0.1 nm, which limits its use in practical applications. Here we describe a technique by which the Brownian amplitude and the Q factor in air and water can be amplified by three and two orders of magnitude, respectively. This technique is similar to a positive feedback oscillator, wherein the Brownian motion of the vibrating cantilever controls the frequency output of the oscillator. This technique can be exploited to improve sensitivity of microcantilever-based chemical and biological sensors, especially for sensors in liquid environments

  4. Active Control Does Not Eliminate Motion-Induced Illusory Displacement

    Directory of Open Access Journals (Sweden)

    Ian M. Thornton

    2011-05-01

    Full Text Available When the sine-wave grating of a Gabor patch drifts to the left or right, the perceived position of the entire object is shifted in the direction of local motion. In the current work we explored whether active control of the physical position of the patch overcomes such motion induced illusory displacement. In Experiment 1 we created a simple computer game and asked participants to continuously guide a Gabor patch along a randomly curving path using a joystick. When the grating inside the Gabor patch was stationary, participants could perform this task without error. When the grating drifted to either left or right, we observed systematic errors consistent with previous reports of motion-induced illusory displacement. In Experiment 2 we created an iPad application where the built-in accelerometer tilt control was used to steer the patch through as series of “gates”. Again, we observed systematic guidance errors that depended on the direction and speed of local motion. In conclusion, we found no evidence that participants could adapt or compensate for illusory displacement given active control of the target.

  5. IPMSM Motion-Sensorless Direct Torque and Flux Control

    DEFF Research Database (Denmark)

    Pitict, Christian Ilie; Andreescu, Gheorghe-Daniel; Blaabjerg, Frede

    2005-01-01

    The paper presents a rather comprehensive implementation of a wide speed motion-sensorless control of IPMSM drives via direct torque and flux control (DTFC) with space vector modulation (SVM). Signal injection with only one D-module vector filter and phase-locked loop (PLL) observer is used at low...... provides for a smooth current waveform even at 1 rpm. The paper demonstrates through ample experiments a 1750 rpm 1 1 rpm speed range full-loaded with sensorless DTFC-SVM....

  6. Stepping-Motion Motor-Control Subsystem For Testing Bearings

    Science.gov (United States)

    Powers, Charles E.

    1992-01-01

    Control subsystem closed-loop angular-position-control system causing motor and bearing under test to undergo any of variety of continuous or stepping motions. Also used to test bearing-and-motor assemblies, motors, angular-position sensors including rotating shafts, and like. Monitoring subsystem gathers data used to evaluate performance of bearing or other article under test. Monitoring subsystem described in article, "Monitoring Subsystem For Testing Bearings" (GSC-13432).

  7. Integrals of Motion for Discrete-Time Optimal Control Problems

    OpenAIRE

    Torres, Delfim F. M.

    2003-01-01

    We obtain a discrete time analog of E. Noether's theorem in Optimal Control, asserting that integrals of motion associated to the discrete time Pontryagin Maximum Principle can be computed from the quasi-invariance properties of the discrete time Lagrangian and discrete time control system. As corollaries, results for first-order and higher-order discrete problems of the calculus of variations are obtained.

  8. Adaptive neural network motion control for aircraft under uncertainty conditions

    Science.gov (United States)

    Efremov, A. V.; Tiaglik, M. S.; Tiumentsev, Yu V.

    2018-02-01

    We need to provide motion control of modern and advanced aircraft under diverse uncertainty conditions. This problem can be solved by using adaptive control laws. We carry out an analysis of the capabilities of these laws for such adaptive systems as MRAC (Model Reference Adaptive Control) and MPC (Model Predictive Control). In the case of a nonlinear control object, the most efficient solution to the adaptive control problem is the use of neural network technologies. These technologies are suitable for the development of both a control object model and a control law for the object. The approximate nature of the ANN model was taken into account by introducing additional compensating feedback into the control system. The capabilities of adaptive control laws under uncertainty in the source data are considered. We also conduct simulations to assess the contribution of adaptivity to the behavior of the system.

  9. Delayless acceleration measurement method for motion control applications

    Energy Technology Data Exchange (ETDEWEB)

    Vaeliviita, S.; Ovaska, S.J. [Helsinki University of Technology, Otaniemi (Finland). Institute of Intelligent Power Electronics

    1997-12-31

    Delayless and accurate sensing of angular acceleration can improve the performance of motion control in motor drives. Acceleration control is, however, seldom implemented in practical drive systems due to prohibitively high costs or unsatisfactory results of most acceleration measurement methods. In this paper we propose an efficient and accurate acceleration measurement method based on direct differentiation of the corresponding velocity signal. Polynomial predictive filtering is used to smooth the resulting noisy signal without delay. This type of prediction is justified by noticing that a low-degree polynomial can usually be fitted into the primary acceleration curve. No additional hardware is required to implement the procedure if the velocity signal is already available. The performance of the acceleration measurement method is evaluated by applying it to a demanding motion control application. (orig.) 12 refs.

  10. Energy efficient motion control of the electric bus on route

    Science.gov (United States)

    Kotiev, G. O.; Butarovich, D. O.; Kositsyn, B. B.

    2018-02-01

    At present, the urgent problem is the reduction of energy costs of urban motor transport. The article proposes a method of solving this problem by developing an energy-efficient law governing the movement of an electric bus along a city route. To solve this problem, an algorithm is developed based on the dynamic programming method. The proposed method allows you to take into account the constraints imposed on the phase coordinates, control action, as well as on the time of the route. In the course of solving the problem, the model of rectilinear motion of an electric bus on a horizontal reference surface is considered, taking into account the assumptions that allow it to be adapted for the implementation of the method. For the formation of a control action in the equations of motion dynamics, an algorithm for changing the traction / braking torque on the wheels of an electric bus is considered, depending on the magnitude of the control parameter and the speed of motion. An optimal phase trajectory was obtained on a selected section of the road for the prototype of an electric bus. The article presents the comparison of simulation results obtained with the optimal energy efficient control law with the results obtained by a test driver. The comparison proved feasibility of the energy efficient control law for the automobile city electric transport.

  11. Hummingbirds control hovering flight by stabilizing visual motion.

    Science.gov (United States)

    Goller, Benjamin; Altshuler, Douglas L

    2014-12-23

    Relatively little is known about how sensory information is used for controlling flight in birds. A powerful method is to immerse an animal in a dynamic virtual reality environment to examine behavioral responses. Here, we investigated the role of vision during free-flight hovering in hummingbirds to determine how optic flow--image movement across the retina--is used to control body position. We filmed hummingbirds hovering in front of a projection screen with the prediction that projecting moving patterns would disrupt hovering stability but stationary patterns would allow the hummingbird to stabilize position. When hovering in the presence of moving gratings and spirals, hummingbirds lost positional stability and responded to the specific orientation of the moving visual stimulus. There was no loss of stability with stationary versions of the same stimulus patterns. When exposed to a single stimulus many times or to a weakened stimulus that combined a moving spiral with a stationary checkerboard, the response to looming motion declined. However, even minimal visual motion was sufficient to cause a loss of positional stability despite prominent stationary features. Collectively, these experiments demonstrate that hummingbirds control hovering position by stabilizing motions in their visual field. The high sensitivity and persistence of this disruptive response is surprising, given that the hummingbird brain is highly specialized for sensory processing and spatial mapping, providing other potential mechanisms for controlling position.

  12. Velocity and Motion Control of a Self-Balancing Vehicle Based on a Cascade Control Strategy

    Directory of Open Access Journals (Sweden)

    Miguel Velazquez

    2016-06-01

    Full Text Available This paper presents balancing, velocity and motion control of a self-balancing vehicle. A cascade controller is implemented for both balancing control and angular velocity control. This controller is tested in simulations using a proposed mathematical model of the system. Motion control is achieved based on the kinematics of the robot. Control hardware is designed and integrated to implement the proposed controllers. Pitch is kept under 1° from the equilibrium position with no external disturbances. The linear cascade control is able to handle slight changes in the system dynamics, such as in the centre of mass and the slope on an inclined surface.

  13. Adaptive fuzzy trajectory control for biaxial motion stage system

    Directory of Open Access Journals (Sweden)

    Wei-Lung Mao

    2016-04-01

    Full Text Available Motion control is an essential part of industrial machinery and manufacturing systems. In this article, the adaptive fuzzy controller is proposed for precision trajectory tracking control in biaxial X-Y motion stage system. The theoretical analyses of direct fuzzy control which is insensitive to parameter uncertainties and external load disturbances are derived to demonstrate the feasibility to track the reference trajectories. The Lyapunov stability theorem has been used to testify the asymptotic stability of the whole system, and all the signals are bounded in the closed-loop system. The intelligent position controller combines the merits of the adaptive fuzzy control with robust characteristics and learning ability for periodic command tracking of a servo drive mechanism. The simulation and experimental results on square, triangle, star, and circle reference contours are presented to show that the proposed controller indeed accomplishes the better tracking performances with regard to model uncertainties. It is observed that the convergence of parameters and tracking errors can be faster and smaller compared with the conventional adaptive fuzzy control in terms of average tracking error and tracking error standard deviation.

  14. Vision Servo Motion Control and Error Analysis of a Coplanar XXY Stage for Image Alignment Motion

    Directory of Open Access Journals (Sweden)

    Hau-Wei Lee

    2013-01-01

    Full Text Available In recent years, as there is demand for smart mobile phones with touch panels, the alignment/compensation system of alignment stage with vision servo control has also increased. Due to the fact that the traditional stacked-type XYθ stage has cumulative errors of assembly and it is heavy, it has been gradually replaced by the coplanar stage characterized by three actuators on the same plane with three degrees of freedom. The simplest image alignment mode uses two cameras as the equipments for feedback control, and the work piece is placed on the working stage. The work piece is usually engraved/marked. After the cameras capture images and when the position of the mark in the camera is obtained by image processing, the mark can be moved to the designated position in the camera by moving the stage and using alignment algorithm. This study used a coplanar XXY stage with 1 μm positioning resolution. Due to the fact that the resolution of the camera is about 3.75 μm per pixel, thus a subpixel technology is used, and the linear and angular alignment repeatability of the alignment system can achieve 1 μm and 5 arcsec, respectively. The visual servo motion control for alignment motion is completed within 1 second using the coplanar XXY stage.

  15. Motion control of a gantry crane with a container

    Science.gov (United States)

    Shugailo, T. S.; Yushkov, M. P.

    2018-05-01

    The transportation of a container by a gantry crane in a given time from one point of space to another is considered. The system is at rest at the end of the motion. A maximum admissible speed is taken into account. The control force is found using either the Pontryagin maximum principle or the generalized Gauss principle. The advantages of the second method over the first one is demonstrated.

  16. Algorithm for motion control of an exoskeleton during verticalization

    Directory of Open Access Journals (Sweden)

    Jatsun Sergey

    2016-01-01

    Full Text Available This paper considers lower limb exoskeleton that performs sit-to-stand motion. The work is focused on the control system design. An application of a null space projection methods for solving inverse kinematics problem is discussed. An adaptive multi-input multi-output regulator for the system is presented with the motivation for that choice. Results of the simulation for different versions of the regulator are shown.

  17. Kinematic control of redundant robots and the motion optimizability measure.

    Science.gov (United States)

    Li, L; Gruver, W A; Zhang, Q; Yang, Z

    2001-01-01

    This paper treats the kinematic control of manipulators with redundant degrees of freedom. We derive an analytical solution for the inverse kinematics that provides a means for accommodating joint velocity constraints in real time. We define the motion optimizability measure and use it to develop an efficient method for the optimization of joint trajectories subject to multiple criteria. An implementation of the method for a 7-dof experimental redundant robot is present.

  18. Motion control of rigid bodies in SE(3)

    Science.gov (United States)

    Roza, Ashton

    This thesis investigates the control of motion for a general class of vehicles that rotate and translate in three-space, and are propelled by a thrust vector which has fixed direction in body frame. The thesis addresses the problems of path following and position control. For path following, a feedback linearization controller is presented that makes the vehicle follow an arbitrary closed curve while simultaneously allowing the designer to specify the velocity profile of the vehicle on the path and its heading. For position control, a two-stage approach is presented that decouples position control from attitude control, allowing for a modular design and yielding almost global asymptotic stability of any desired hovering equilibrium. The effectiveness of the proposed method is verified both in simulation and experimentally by means of a hardware-in-the-loop setup emulating a co-axial helicopter.

  19. H∞ control for path tracking of autonomous underwater vehicle motion

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-05-01

    Full Text Available In order to simplify the design of path tracking controller and solve the problem relating to nonlinear dynamic model of autonomous underwater vehicle motion planning, feedback linearization method is first adopted to transform the nonlinear dynamic model into an equivalent pseudo-linear dynamic model in horizontal coordinates. Then considering wave disturbance effect, mixed-sensitivity method of H∞ robust control is applied to design state-feedback controller for this equivalent dynamic model. Finally, control law of pseudo-linear dynamic model is transformed into state (surge velocity and yaw angular rate tracking control law of nonlinear dynamic model through inverse coordinate transformation. Simulation indicates that autonomous underwater vehicle path tracking is successfully implemented with this proposed method, and the influence of parameter variation in autonomous underwater vehicle dynamic model on its tracking performance is reduced by H∞ controller. All the results show that the method proposed in this article is effective and feasible.

  20. Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

    OpenAIRE

    Lyons, Elizabeth J.; Tate, Deborah F.; Ward, Dianne S.; Ribisl, Kurt M.; Bowling, J. Michael; Kalyanaraman, Sriram

    2012-01-01

    Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0....

  1. Geometric Control Over the Motion of Magnetic Domain Walls

    International Nuclear Information System (INIS)

    N.A. Sinitsyn; V.V. Dobrovitski; S. urazhdin; Avadh Saxena

    2008-01-01

    We propose a method that enables a precise control of magnetic patterns and relies only on the fundamental properties of the wire as well as on the choice of the path in the controlled parameter space but not on the rate of motion along this path. Possible experimental realizations of this mechanism are discussed. In particular, we show that the domain walls in magnetic nanowires can be translated by rotation of the magnetic easy axis or by applying pulses of magnetic field directed transverse to the magnetic easy axis

  2. Cohesive Motion Control Algorithm for Formation of Multiple Autonomous Agents

    Directory of Open Access Journals (Sweden)

    Debabrata Atta

    2010-01-01

    Full Text Available This paper presents a motion control strategy for a rigid and constraint consistent formation that can be modeled by a directed graph whose each vertex represents individual agent kinematics and each of directed edges represents distance constraints maintained by an agent, called follower, to its neighbouring agent. A rigid and constraint consistent graph is called persistent graph. A persistent graph is minimally persistent if it is persistent, and no edge can be removed without losing its persistence. An acyclic (free of cycles in its sensing pattern minimally persistent graph of Leader-Follower structure has been considered here which can be constructed from an initial Leader-Follower seed (initial graph with two vertices, one is Leader and another one is First Follower and one edge in between them is directed towards Leader by Henneberg sequence (a procedure of growing a graph containing only vertex additions. A set of nonlinear optimization-based decentralized control laws for mobile autonomous point agents in two dimensional plane have been proposed. An infinitesimal deviation in formation shape created continuous motion of Leader is compensated by corresponding continuous motion of other agents fulfilling the shortest path criteria.

  3. Redox control of molecular motion in switchable artificial nanoscale devices.

    Science.gov (United States)

    Credi, Alberto; Semeraro, Monica; Silvi, Serena; Venturi, Margherita

    2011-03-15

    The design, synthesis, and operation of molecular-scale systems that exhibit controllable motions of their component parts is a topic of great interest in nanoscience and a fascinating challenge of nanotechnology. The development of this kind of species constitutes the premise to the construction of molecular machines and motors, which in a not-too-distant future could find applications in fields such as materials science, information technology, energy conversion, diagnostics, and medicine. In the past 25 years the development of supramolecular chemistry has enabled the construction of an interesting variety of artificial molecular machines. These devices operate via electronic and molecular rearrangements and, like the macroscopic counterparts, they need energy to work as well as signals to communicate with the operator. Here we outline the design principles at the basis of redox switching of molecular motion in artificial nanodevices. Redox processes, chemically, electrically, or photochemically induced, can indeed supply the energy to bring about molecular motions. Moreover, in the case of electrically and photochemically induced processes, electrochemical and photochemical techniques can be used to read the state of the system, and thus to control and monitor the operation of the device. Some selected examples are also reported to describe the most representative achievements in this research area.

  4. Autonomous vehicle motion control, approximate maps, and fuzzy logic

    Science.gov (United States)

    Ruspini, Enrique H.

    1993-01-01

    Progress on research on the control of actions of autonomous mobile agents using fuzzy logic is presented. The innovations described encompass theoretical and applied developments. At the theoretical level, results of research leading to the combined utilization of conventional artificial planning techniques with fuzzy logic approaches for the control of local motion and perception actions are presented. Also formulations of dynamic programming approaches to optimal control in the context of the analysis of approximate models of the real world are examined. Also a new approach to goal conflict resolution that does not require specification of numerical values representing relative goal importance is reviewed. Applied developments include the introduction of the notion of approximate map. A fuzzy relational database structure for the representation of vague and imprecise information about the robot's environment is proposed. Also the central notions of control point and control structure are discussed.

  5. Influence of Vibrotactile Feedback on Controlling Tilt Motion After Spaceflight

    Science.gov (United States)

    Wood, S. J.; Rupert, A. H.; Vanya, R. D.; Esteves, J. T.; Clement, G.

    2011-01-01

    We hypothesize that adaptive changes in how inertial cues from the vestibular system are integrated with other sensory information leads to perceptual disturbances and impaired manual control following transitions between gravity environments. The primary goals of this ongoing post-flight investigation are to quantify decrements in manual control of tilt motion following short-duration spaceflight and to evaluate vibrotactile feedback of tilt as a sensorimotor countermeasure. METHODS. Data is currently being collected on 9 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s, body axis, thereby eliciting canal reflexes without concordant otolith or visual cues. A simple 4 tactor system was implemented to provide feedback when tilt position exceeded predetermined levels in either device. Closed-loop nulling tasks are performed during random tilt steps or sum-of-sines (TTS only) with and without vibrotactile feedback of chair position. RESULTS. On landing day the manual control performance without vibrotactile feedback was reduced by >30% based on the gain or the amount of tilt disturbance successfully nulled. Manual control performance tended to return to baseline levels within 1-2 days following landing. Root-mean-square position error and tilt velocity were significantly reduced with vibrotactile feedback. CONCLUSIONS. These preliminary results are consistent with our hypothesis that adaptive changes in vestibular processing corresponds to reduced manual control performance following G-transitions. A simple vibrotactile prosthesis improves the ability to null out tilt motion within a limited range of motion disturbances.

  6. Coordinated Control of Wave Energy Converters Subject to Motion Constraints

    Directory of Open Access Journals (Sweden)

    Liguo Wang

    2016-06-01

    Full Text Available In this paper, a generic coordinated control method for wave energy converters is proposed, and the constraints on motion amplitudes and the hydrodynamic interaction between converters are considered. The objective of the control problem is to maximize the energy converted from ocean waves, and this is achieved by coordinating the power take-off (PTO damping of each wave energy converter in the frequency domain in each sea state. In a case study, a wave energy farm consisting of four converters based on the concept developed by Uppsala University is studied. In the solution, motion constraints, including constraints on the amplitudes of displacement and velocity, are included. Twelve months of sea states, based on measured wave data at the Lysekil test site on the Swedish west coast, are used in the simulation to evaluate the performance of the wave energy farm using the new method. Results from the new coordinated control method and traditional control method are compared, indicating that the coordinated control of wave energy converters is an effective way to improve the energy production of wave energy farm in harmonic waves.

  7. Advanced motion control for next-generation precision mechatronics: Challenges for control, identification, and learning

    NARCIS (Netherlands)

    Oomen, Tom

    2017-01-01

    Manufacturing equipment and scientific instruments, including wafer scanners, printers, microscopes, and medical imaging scanners, require accurate and fast motions. Increasing requirements necessitate enhanced control performance. The aim of this paper is to identify several challenges for advanced

  8. STcontrol and NEWPORT Motion Controller Model ESP 301 Device

    CERN Document Server

    Kapanadze, Giorgi

    2015-01-01

    Pixel detectors are used to detect particle tracks in LHC experiments. This kind of detectors are built with silicon semiconductor diodes. Ionizing particles create charge in the diode and the reverse bias voltage creates electric field in the diode which causes effective charge collection by the drift of electrons [1]. One of the main parameter of tracker detectors is efficiency. The efficiency as a function of position in the pixel matrix can be evaluated by scanning the matrix with red and infrared lasers. It is important to know what is happening between pixels in terms of efficiency. We perform these measurements to test new type of pixel detectors for the LHC future upgrade in 2023. New type of detectors are needed because the radiation level will be much higher [2]. For the measurements we need to control a stage motion controller (NEWPORT Motion Controller Model ESP 301) with the existing software STcontrol, which is used for readout data from pixel detectors and to control other devices like the lase...

  9. Pengenalan Isyarat Tangan Menggunakan Leap Motion Controller untuk Pertunjukan Boneka Tangan Virtual

    OpenAIRE

    Dzulkarnain, Iskandar; Sumpeno, Surya; Christyowidiasmoro, Christyowidiasmoro

    2016-01-01

    Leap Motion Controller memiliki keterbatasan dalam menangkap gerak isyarat tangan. Keterbatasan tersebut menyebabkan gerakan tangan model boneka virtual tidak seakurat gerakan tangan pelakon. Selain itu, konfigurasi bone model dimensi tiga untuk Leap Motion Controller berbeda dengan konfigurasi bone dimensi tiga pada umumnya. Oleh karena itu, dilakukan pengenalan isyarat tangan menggunakan Leap Motion Controller untuk pertunjukan boneka tangan virtual. Pengenalan isyarat tangan tersebut dilak...

  10. An evaluation of control rod motion simulator of research reactor

    International Nuclear Information System (INIS)

    Sanda

    2010-01-01

    Motion simulator for rod control research reactor has been carried out using a servo motor. Reactor rod motion control at any point should be in the right position, one of the motors that can move in a precise and correct is the servo motor. To ensure that the servo motor to move in accordance with the desired program, then the servo motor function test should be carried out to ensure having good performance. Tests carried out on meshes stress disorder, the load is stable within a certain period and travel time safety control rod up and down, travel time regulating control rods up and down and travel time compensation control rods up and down. In testing the breakdown voltage V out nets at 24 V, 6.5 A with 12 Q load deviation obtained V0= V1 = 0.1% and 0.65% and for the stability of the load in a certain time deviation V = 0.7125% , next to the breakdown voltage V out nets at 12 V, 4.2 A with a 6 Q load deviation obtained V0= V1 = 0.275% and 1.158% for the stability of the load in a certain time deviation V = 1.463% and the net-voltage noise nets on V out 24 V, 4.5 A with 12 Q load deviation obtained V0 = V1 = 0.196% and 0.496% and for the stability of the load in a certain time deviation V = 0.3625%. While the travel time of a safety control rod up and down, up and down the regulator and compensation rise and fall showed a steady linear graph. The results show that the performance of the servo motor is very stable with the working area below the tolerance limit, it is 5% - 10%.(author)

  11. Evaluation of control rod motion simulator research reactors

    International Nuclear Information System (INIS)

    Sanda

    2010-01-01

    Motion simulator has been carried out testing of the reactor control rod using a servomotor. Reactor control rod motion at any point should be in the right position, one of the motors that can move in a precise and correct the servo motor. To ensure that the servo motor to move in accordance with the desired program, then the servomotor function test for motor work to ensure the performance of the appliance. Tests carried out on meshes stress disorder, the load is stable within a certain period and travel time safety control rod up and down, travel time regulating control rods up and down and travel time compensation control rods up and down. In testing the breakdown voltage Vout nets at 24 V, 6.5 A with 12 Ω load deviation obtained V0 = V1 = 0.1% and 0.65% and for the stability of the load in a certain time deviation V = 0.7125%, next to the breakdown voltage Vout nets at 12V, 4.2 A with a 6 Ω load deviation obtained V0 = V1 = 0.275% and 1.158% for the stability of the load in a certain time deviation V = 1.463% and the net-voltage noise nets on Vout 24 V, 4.5 A with 12 Ω load deviation obtained V0 = V1 = 0.196% and 0.496% and for the stability of the load in a certain time deviation V = 0.3625%. While the travel time of a safety control rod up and down, up and down the regulator and compensation rise and fall showed a steady linear graph. The results show that the performance of the servo motor is very stable with the working area below the tolerance limit, it is 5% - 10%. (author)

  12. Interactions Controlling the Slow Dynamic Conformational Motions of Ubiquitin

    Directory of Open Access Journals (Sweden)

    Soichiro Kitazawa

    2017-08-01

    Full Text Available Rational mutation of proteins based on their structural and dynamic characteristics is a useful strategy for amplifying specific fluctuations in proteins. Here, we show the effects of mutation on the conformational fluctuations and thermodynamic stability of ubiquitin. In particular, we focus on the salt bridge between K11 and E34 and the hydrogen bond between I36 and Q41, which are predicted to control the fluctuation between the basic folded state, N1, and the alternatively folded state, N2, of the protein, using high-pressure NMR spectroscopy. The E34A mutation, which disrupts the salt bridge, did not alter picosecond–to–nanosecond, microsecond–to–millisecond dynamic motions, and stability of the protein, while the Q41N mutation, which destabilizes the hydrogen bond, specifically amplified the N1–N2 conformational fluctuation and decreased stability. Based on the observed thermodynamic stabilities of the various conformational states, we showed that in the Q41N mutant, the N1 state is more significantly destabilized than the N2 state, resulting in an increase in the relative population of N2. Identifying the interactions controlling specific motions of a protein will facilitate molecular design to achieve functional dynamics beyond native state dynamics.

  13. Relative dynamics and motion control of nanosatellite formation flying

    Science.gov (United States)

    Pimnoo, Ammarin; Hiraki, Koju

    2016-04-01

    Orbit selection is a necessary factor in nanosatellite formation mission design/meanwhile, to keep the formation, it is necessary to consume fuel. Therefore, the best orbit design for nanosatellite formation flying should be one that requires the minimum fuel consumption. The purpose of this paper is to analyse orbit selection with respect to the minimum fuel consumption, to provide a convenient way to estimate the fuel consumption for keeping nanosatellite formation flying and to present a simplified method of formation control. The formation structure is disturbed by J2 gravitational perturbation and other perturbing accelerations such as atmospheric drag. First, Gauss' Variation Equations (GVE) are used to estimate the essential ΔV due to the J2 perturbation and atmospheric drag. The essential ΔV presents information on which orbit is good with respect to the minimum fuel consumption. Then, the linear equations which account for J2 gravitational perturbation of Schweighart-Sedwick are presented and used to estimate the fuel consumption to maintain the formation structure. Finally, the relative dynamics motion is presented as well as a simplified motion control of formation structure by using GVE.

  14. Simulating control rod and fuel assembly motion using moving meshes

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, D. [Department of Electrical and Computer Engineering, McMaster University, 1280 Main Street West, Hamilton Ontario, L8S 4K1 (Canada)], E-mail: gilbertdw1@gmail.com; Roman, J.E. [Departamento de Sistemas Informaticos y Computacion, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Garland, Wm. J. [Department of Engineering Physics, McMaster University, 1280 Main Street West, Hamilton Ontario, L8S 4K1 (Canada); Poehlman, W.F.S. [Department of Computing and Software, McMaster University, 1280 Main Street West, Hamilton Ontario, L8S 4K1 (Canada)

    2008-02-15

    A prerequisite for designing a transient simulation experiment which includes the motion of control and fuel assemblies is the careful verification of a steady state model which computes k{sub eff} versus assembly insertion distance. Previous studies in nuclear engineering have usually approached the problem of the motion of control rods with the use of nonlinear nodal models. Nodal methods employ special approximations for the leading and trailing cells of the moving assemblies to avoid the rod cusping problem which results from the naive volume weighted cell cross-section approximation. A prototype framework called the MOOSE has been developed for modeling moving components in the presence of diffusion phenomena. A linear finite difference model is constructed, solutions for which are computed by SLEPc, a high performance parallel eigenvalue solver. Design techniques for the implementation of a patched non-conformal mesh which links groups of sub-meshes that can move relative to one another are presented. The generation of matrices which represent moving meshes which conserve neutron current at their boundaries, and the performance of the framework when applied to model reactivity insertion experiments is also discussed.

  15. Learning Silhouette Features for Control of Human Motion

    National Research Council Canada - National Science Library

    Ren, Liu; Shakhnarovich, Gregory; Hodgins, Jessica K; Pfister, Hanspeter; Viola, Paul A

    2004-01-01

    .... The system combines information about the user's motion contained in silhouettes from several viewpoints with domain knowledge contained in a motion capture database to interactively produce a high quality animation...

  16. Relative roughness controls on incipient sediment motion in steep channels

    Science.gov (United States)

    Prancevic, J.; Lamb, M. P.; Fuller, B. M.

    2012-12-01

    For over eight decades, researchers have noted an appreciable increase in the nondimensional shear stress (Shields number) at initiation of fluvial bedload transport with increasing bed slope. The precise cause of the trend, however, is obscured by the covariance of several factors with increased slope: a greater downstream component of the gravity acting on the grains and fluid, changes in bed morphology, increased grainsize relative to the channel width that may lead to grain bridging, and increased grainsize relative to flow depth (relative roughness) that may change flow hydraulics and particle buoyancy. Here, we report on ongoing laboratory experiments spanning a wide range of bed slopes (2% to 67%) designed to isolate these variables and determine the true cause of heightened critical Shields numbers on steep slopes. First, we eliminated bed morphology as a factor by using only planar beds. To investigate the effect of grain bridging, we used two different channel widths, representing width-to-grainsize ratios of 23:1 and 9:1. Finally, to separate the effects of slope from relative roughness, we compared incipient motion conditions for acrylic particles (submerged specific gravity of 0.15) to natural siliciclastic gravel (submerged specific gravity of 1.65). Different particle densities allowed us to explore incipient motion as a function of relative roughness, independent of channel slope, because lighter particles move at shallower flow depths than heavier ones of the same size. Results show that both materials exhibit a positive trend between bed slope and critical Shields number despite the existence of planar beds for all slopes. Furthermore, changing the grainsize-to-width ratio had a negligible effect on this trend. For all slopes, the critical Shields number for bedload transport was higher for the acrylic particles than for gravel, indicating that relative roughness has a strong control on incipient sediment motion independent of channel slope. These

  17. The Digital Motion Control System for the Submillimeter Array Antennas

    Science.gov (United States)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.; Patel, N. A.; Blundell, R.; Christensen, R. D.; Diven, A. R.; Maute, J.; Plante, R. J.; Riddle, P.; Young, K. H.

    2013-09-01

    We describe the design and performance of the digital servo and motion control system for the 6-meter parabolic antennas of the Submillimeter Array (SMA) on Mauna Kea, Hawaii. The system is divided into three nested layers operating at a different, appropriate bandwidth. (1) A rack-mounted, real-time Unix system runs the position loop which reads the high resolution azimuth and elevation encoders and sends velocity and acceleration commands at 100 Hz to a custom-designed servo control board (SCB). (2) The microcontroller-based SCB reads the motor axis tachometers and implements the velocity loop by sending torque commands to the motor amplifiers at 558 Hz. (3) The motor amplifiers implement the torque loop by monitoring and sending current to the three-phase brushless drive motors at 20 kHz. The velocity loop uses a traditional proportional-integral-derivative (PID) control algorithm, while the position loop uses only a proportional term and implements a command shaper based on the Gauss error function. Calibration factors and software filters are applied to the tachometer feedback prior to the application of the servo gains in the torque computations. All of these parameters are remotely adjustable in the software. The three layers of the control system monitor each other and are capable of shutting down the system safely if a failure or anomaly occurs. The Unix system continuously relays the antenna status to the central observatory computer via reflective memory. In each antenna, a Palm Vx hand controller displays the complete system status and allows full local control of the drives in an intuitive touchscreen user interface. The hand controller can also be connected outside the cabin, a major convenience during the frequent reconfigurations of the interferometer. Excellent tracking performance ( 0.3‧‧ rms) is achieved with this system. It has been in reliable operation on 8 antennas for over 10 years and has required minimal maintenance.

  18. Pitch Motion Stabilization by Propeller Speed Control Using Statistical Controller Design

    DEFF Research Database (Denmark)

    Nakatani, Toshihiko; Blanke, Mogens; Galeazzi, Roberto

    2006-01-01

    This paper describes dynamics analysis of a small training boat and a possibility of ship pitch stabilization by control of propeller speed. After upgrading the navigational system of an actual small training boat, in order to identify the model of the ship, the real data collected by sea trials...... were used for statistical analysis and system identification. This analysis shows that the pitching motion is indeed influenced by engine speed and it is suggested that there exists a possibility of reducing the pitching motion by properly controlling the engine throttle. Based on this observation...

  19. Controlled motion of domain walls in submicron amorphous wires

    Energy Technology Data Exchange (ETDEWEB)

    Ţibu, Mihai; Lostun, Mihaela; Rotărescu, Cristian; Atiţoaie, Alexandru; Lupu, Nicoleta; Óvári, Tibor-Adrian, E-mail: taovari@phys-iasi.ro; Chiriac, Horia [Department of Magnetic Materials and Devices, National Institute of Research and Development for Technical Physics, Iaşi, 700050 (Romania); Allwood, Dan A. [Department of Materials Science and Engineering, University of Sheffield, Sheffield, S1 3JD (United Kingdom)

    2016-05-15

    Results on the control of the domain wall displacement in cylindrical Fe{sub 77.5}Si{sub 7.5}B{sub 15} amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB) system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse.

  20. Passive motion paradigm: an alternative to optimal control.

    Science.gov (United States)

    Mohan, Vishwanathan; Morasso, Pietro

    2011-01-01

    IN THE LAST YEARS, OPTIMAL CONTROL THEORY (OCT) HAS EMERGED AS THE LEADING APPROACH FOR INVESTIGATING NEURAL CONTROL OF MOVEMENT AND MOTOR COGNITION FOR TWO COMPLEMENTARY RESEARCH LINES: behavioral neuroscience and humanoid robotics. In both cases, there are general problems that need to be addressed, such as the "degrees of freedom (DoFs) problem," the common core of production, observation, reasoning, and learning of "actions." OCT, directly derived from engineering design techniques of control systems quantifies task goals as "cost functions" and uses the sophisticated formal tools of optimal control to obtain desired behavior (and predictions). We propose an alternative "softer" approach passive motion paradigm (PMP) that we believe is closer to the biomechanics and cybernetics of action. The basic idea is that actions (overt as well as covert) are the consequences of an internal simulation process that "animates" the body schema with the attractor dynamics of force fields induced by the goal and task-specific constraints. This internal simulation offers the brain a way to dynamically link motor redundancy with task-oriented constraints "at runtime," hence solving the "DoFs problem" without explicit kinematic inversion and cost function computation. We argue that the function of such computational machinery is not only restricted to shaping motor output during action execution but also to provide the self with information on the feasibility, consequence, understanding and meaning of "potential actions." In this sense, taking into account recent developments in neuroscience (motor imagery, simulation theory of covert actions, mirror neuron system) and in embodied robotics, PMP offers a novel framework for understanding motor cognition that goes beyond the engineering control paradigm provided by OCT. Therefore, the paper is at the same time a review of the PMP rationale, as a computational theory, and a perspective presentation of how to develop it for designing

  1. Passive Motion Paradigm: an alternative to Optimal Control

    Directory of Open Access Journals (Sweden)

    Vishwanathan eMohan

    2011-12-01

    Full Text Available In the last years, optimal control theory (OCT has emerged as the leading approach for investigating neural control of movement and motor cognition for two complementary research lines: behavioural neuroscience and humanoid robotics. In both cases, there are general problems that need to be addressed, such as the ‘degrees of freedom problem’, the common core of production, observation, reasoning, and learning of ‘actions’. OCT, directly derived from engineering design techniques of control systems quantifies task goals as ‘cost functions’ and uses the sophisticated formal tools of optimal control to obtain desired behaviour (and predictions. We propose an alternative ‘softer’ approach (PMP: Passive Motion Paradigm that we believe is closer to the biomechanics and cybernetics of action. The basic idea is that actions (overt and overt are the consequences of an internal simulation process that ‘animates’ the body schema with the attractor dynamics of force fields induced by the goal and task specific constraints. This internal simulation offers the brain a way to dynamically link motor redundancy with task oriented constraints ‘at runtime’, hence solving the ‘degrees of freedom problem’ without explicit kinematic inversion and cost function computation. We argue that the function of such computational machinery is not only to shape motor output during action execution but also to provide the self with information on the feasibility, consequence, understanding and meaning of ‘potential actions’. In this sense, taking into account recent developments in neuroscience (motor imagery, simulation theory, mirror neurons and in embodied robotics, PMP offers a novel framework for understanding motor cognition that goes beyond the engineering control paradigm provided by OCT. Therefore, the paper is at the same time a review of the PMP rationale, as a computational theory, and a perspective presentation of how to develop it

  2. The synchronization of loosely coupled motion control systems

    Energy Technology Data Exchange (ETDEWEB)

    Tuominen, P. [VTT Automation, Tampere (Finland). Machine Automation

    1996-12-31

    The aim of this thesis is to create an easily implemented, effective, dynamically schedulable flow control method, and to show how the methods introduced can be analysed using fixed priority scheduling. One of the most important problems in a distributed system is the delay and variation of it (the jitter) caused by a serial based network, especially when media load is relatively high. This thesis has looked for possibilities to implement a deterministic motion control system which can also operate with high media loads. The problem of end-to-end delay in distributed control systems has been addressed. The most promising ones are based on the two window concept, where critical messages are transmitted in the statically scheduled part of window while other, non-critical messages are transmitted in the remaining part. The concept of the chained link is introduced and it is shown how the latency time of a certain set of messages can be controlled. This thesis has introduced the detailed characteristics of this easy-to-assemble chain which is simpler than time or sync-message based methods used commercially. One benefit is that only those nodes needing synchronization must support synchronization tasks. Other nodes are exempt from supporting unnecessary functions, making system programming easier. The chain can be scheduled dynamically as one long message. The concept of a CAN based producer-consumer method, a statical scheduling method which can be used with a bus-master has been introduced. A hydraulic mobile is used as a practical example for analysing and comparing the introduced distribution and flow control methods

  3. Complex motion of a vehicle through a series of signals controlled by power-law phase

    Science.gov (United States)

    Nagatani, Takashi

    2017-07-01

    We study the dynamic motion of a vehicle moving through the series of traffic signals controlled by the position-dependent phase of power law. All signals are controlled by both cycle time and position-dependent phase. The dynamic model of the vehicular motion is described in terms of the nonlinear map. The vehicular motion varies in a complex manner by varying cycle time for various values of the power of the position-dependent phase. The vehicle displays the periodic motion with a long cycle for the integer power of the phase, while the vehicular motion exhibits the very complex behavior for the non-integer power of the phase.

  4. Space motion sickness: The sensory motor controls and cardiovascular correlation

    Science.gov (United States)

    Souvestre, Philippe A.; Blaber, Andrew P.; Landrock, Clinton K.

    Background and PurposeSpace motion sickness (SMS) and related symptoms remain a major limiting factor in Space operations. A recent comprehensive literature review [J.R. Lackner, Z. DiZio, Space motion sickness, Experimental Brain Research 175 (2006) 377-399, doi 10.1007/s00221-006-0697-y] concluded that SMS does not represent a unique diagnostic entity, and there is no adequate predictor of SMS' susceptibility and severity. No countermeasure has been found reliable to prevent or treat SMS symptoms onset. Recent neurophysiological findings on sensory-motor controls monitoring [P.A. Souvestre, C. Landrock, Biomedical-performance monitoring and assessment of astronauts by means of an ocular vestibular monitoring system, Acta Astronautica, 60 (4-7) (2007) 313-321, doi:10.1016/j.actaastro.2006.08.013] and heart-rate variability (HRV) measurements relationship could explain post-flight orthostatic intolerance (PFOI) in astronauts [A.P. Blaber, R.L. Bondar, M.S. Kassam, Heart rate variability and short duration space flight: relationship to post-flight orthostatic intolerance, BMC Physiology 4 (2004) 6]. These two methodologies are generally overlooked in SMS' analysis. In this paper we present the case for a strong relationship between sensory-motor controls related symptoms, including orthostatic intolerance (OI) and SMS symptoms. MethodsThis paper expands on several previously published papers [J.R. Lackner, Z. DiZio, Space motion sickness, Experimental Brain Research 175 (2006) 377-399, doi 10.1007/s00221-006-0697-y; P.A. Souvestre, C. Landrock, Biomedical-performance monitoring and assessment of astronauts by means of an ocular vestibular monitoring system, Acta Astronautica, 60 (4-7) (2007) 313-321, doi:10.1016/j.actaastro.2006.08.013] along with an updated literature review. An analysis of a 10-year period clinical data from trauma patients experiencing postural deficiency syndrome (PDS) show assessment and monitoring techniques which successfully identify trauma

  5. Measurements and simulation of controlled beamfront motion in the Laser Controlled Collective Accelerator

    International Nuclear Information System (INIS)

    Yao, R.L.; Destler, W.W.; Striffler, C.D.; Rodgers, J.; Scgalov, Z.

    1989-01-01

    In the Laser Controlled Collective Accelerator, an intense electron beam is injected at a current above the vacuum space charge limit into an initially evacuated drift tube. A plasma channel, produced by time-sequenced, multiple laser beam ionization of a solid target on the drift tube wall, provides the necessary neutralization to allow for effective beam propagation. By controlling the rate of production of the plasma channel as a function of time down the drift tube, control of the electron beamfront can be achieved. Recent experimental measurements of controlled beamfront motion in this configuration are presented, along with results of ion acceleration experiments conducted using two different accelerating gradients. These results are compared with numerical simulations of the system in which both controlled beamfront motion and ion acceleration is observed consistent with both design expectations and experimental results. 5 refs., 6 figs

  6. Control of humanoid robot motions with impacts : numerical experiments with reference spreading control

    NARCIS (Netherlands)

    Rijnen, M.W.L.M.; De Mooij, E.B.C.; Traversaro, S.; Nori, F.; Van De Wouw, N.; Saccon, A.; Nijmeijer, H.

    2017-01-01

    This work explores the stabilization of desired dynamic motion tasks involving hard impacts at non-negligible speed for humanoid robots. To this end, a so-called reference spreading hybrid control law is designed showing promising results in simulation. The simulations are performed employing a

  7. An intelligent control scheme for precise tip-motion control in atomic force microscopy.

    Science.gov (United States)

    Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

    2016-01-01

    The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. © Wiley Periodicals, Inc.

  8. Contrast gain control in first- and second-order motion perception.

    Science.gov (United States)

    Lu, Z L; Sperling, G

    1996-12-01

    A novel pedestal-plus-test paradigm is used to determine the nonlinear gain-control properties of the first-order (luminance) and the second-order (texture-contrast) motion systems, that is, how these systems' responses to motion stimuli are reduced by pedestals and other masking stimuli. Motion-direction thresholds were measured for test stimuli consisting of drifting luminance and texture-contrast-modulation stimuli superimposed on pedestals of various amplitudes. (A pedestal is a static sine-wave grating of the same type and same spatial frequency as the moving test grating.) It was found that first-order motion-direction thresholds are unaffected by small pedestals, but at pedestal contrasts above 1-2% (5-10 x pedestal threshold), motion thresholds increase proportionally to pedestal amplitude (a Weber law). For first-order stimuli, pedestal masking is specific to the spatial frequency of the test. On the other hand, motion-direction thresholds for texture-contrast stimuli are independent of pedestal amplitude (no gain control whatever) throughout the accessible pedestal amplitude range (from 0 to 40%). However, when baseline carrier contrast increases (with constant pedestal modulation amplitude), motion thresholds increase, showing that gain control in second-order motion is determined not by the modulator (as in first-order motion) but by the carrier. Note that baseline contrast of the carrier is inherently independent of spatial frequency of the modulator. The drastically different gain-control properties of the two motion systems and prior observations of motion masking and motion saturation are all encompassed in a functional theory. The stimulus inputs to both first- and second-order motion process are normalized by feedforward, shunting gain control. The different properties arise because the modulator is used to control the first-order gain and the carrier is used to control the second-order gain.

  9. Internal Mass Motion for Spacecraft Dynamics and Control

    National Research Council Canada - National Science Library

    Hall, Christopher D

    2008-01-01

    We present a detailed description of the application of a noncanonical Hamiltonian formulation to the modeling, analysis, and simulation of the dynamics of gyrostat spacecraft with internal mass motion...

  10. Effects of Different Heave Motion Components on Pilot Pitch Control Behavior

    Science.gov (United States)

    Zaal, Petrus M. T.; Zavala, Melinda A.

    2016-01-01

    The study described in this paper had two objectives. The first objective was to investigate if a different weighting of heave motion components decomposed at the center of gravity, allowing for a higher fidelity of individual components, would result in pilot manual pitch control behavior and performance closer to that observed with full aircraft motion. The second objective was to investigate if decomposing the heave components at the aircraft's instantaneous center of rotation rather than at the center of gravity could result in additional improvements in heave motion fidelity. Twenty-one general aviation pilots performed a pitch attitude control task in an experiment conducted on the Vertical Motion Simulator at NASA Ames under different hexapod motion conditions. The large motion capability of the Vertical Motion Simulator also allowed for a full aircraft motion condition, which served as a baseline. The controlled dynamics were of a transport category aircraft trimmed close to the stall point. When the ratio of center of gravity pitch heave to center of gravity heave increased in the hexapod motion conditions, pilot manual control behavior and performance became increasingly more similar to what is observed with full aircraft motion. Pilot visual and motion gains significantly increased, while the visual lead time constant decreased. The pilot visual and motion time delays remained approximately constant and decreased, respectively. The neuromuscular damping and frequency both decreased, with their values more similar to what is observed with real aircraft motion when there was an equal weighting of the heave of the center of gravity and heave due to rotations about the center of gravity. In terms of open- loop performance, the disturbance and target crossover frequency increased and decreased, respectively, and their corresponding phase margins remained constant and increased, respectively. The decomposition point of the heave components only had limited

  11. Laser control of atomic beam motion and applications

    International Nuclear Information System (INIS)

    Balykin, V.I.; Letokhov, V.S.

    1987-01-01

    The authors present the results of an experimental investigation of the control of atomic beam motion by the light pressure of laser radiation. Collimation, focusing and reflection of the atomic beam are considered. Collimation of the atomic beam is achieved by the interaction of laser radiation with atoms, when the light pressure force depends only on the atom's velocity. A similar regime of atomic beam interaction with radiation was performed with transversal irradiation of a beam by the axis-symmetrical field. The axis-symmetrical field was formed by laser radiation reflected from the conical mirror surface of a reflecting axicon. The axis of the atomic beam coincided with that of the axicon. The collimation regime was reached under negative detuning of the laser radiation frequency from the atomic transition frequency by a value equal to several homogeneous widths. With positive detuning by the same value the regime of beam decollimation was observed. The density of atoms on the beam axis was changed by 10 3 times, when the collimation regime was replaced by that of decollimation. Focusing of the atomic beam was achieved by light pressure dependent on the atomic coordinate. Focusing was performed within the field configuration formed by divergent laser Gaussian beams propagating in the direction +- X, +- Y of a Cartesian coordinate system. Waists of the laser beams were an equal distance from the atomic beam axis. With an atomic beam propagating along the z axis, expressions for local distance and a formula for the laser lens were obtained. Focusing of the atomic beam was experimentally accomplished, and the image of the atomic beam was received. In this work they also investigated reflection of the atomic beam by laser radiation. The possibility of creating the optics of a neutral atomic beam is shown

  12. Control of a virtual ambulation influences body movement and motion sickness

    Directory of Open Access Journals (Sweden)

    Hagstrom Jens

    2011-12-01

    Full Text Available Drivers typically are less susceptible to motion sickness than passengers. The influence of vehicle control has theoretical implications for the etiology of motion sickness, and has practical implications for the design of virtual environments. In the present study, participants either controlled or did not control a nonvehicular virtual avatar (i.e., an ambulatory character in a console video game. We examined the incidence of motion sickness and patterns of movement of the head and torso as participants either played or watched the game. Motion sickness incidence was lower when controlling the virutal avatar than when watching an avatar that was controlled by someone else. Patterns of head and torso movement differed between particpants who did and did not control the avatar. Indepenently, patterns of movement differed between participants who reported motion sickness and those who did not. The results suggest that motion sickness is influenced by control of stimulus motion, whether that motion arises from a vehicle or from any other source. We consider implications for the design of humancomputer interfaces.

  13. A Digital Motion Control System for Large Telescopes

    Science.gov (United States)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.

    2001-05-01

    We have designed and programmed a digital motion control system for large telescopes, in particular, the 6-meter antennas of the Submillimeter Array on Mauna Kea. The system consists of a single robust, high-reliability microcontroller board which implements a two-axis velocity servo while monitoring and responding to critical safety parameters. Excellent tracking performance has been achieved with this system (0.3 arcsecond RMS at sidereal rate). The 24x24 centimeter four-layer printed circuit board contains a multitude of hardware devices: 40 digital inputs (for limit switches and fault indicators), 32 digital outputs (to enable/disable motor amplifiers and brakes), a quad 22-bit ADC (to read the motor tachometers), four 16-bit DACs (that provide torque signals to the motor amplifiers), a 32-LED status panel, a serial port to the LynxOS PowerPC antenna computer (RS422/460kbps), a serial port to the Palm Vx handpaddle (RS232/115kbps), and serial links to the low-resolution absolute encoders on the azimuth and elevation axes. Each section of the board employs independent ground planes and power supplies, with optical isolation on all I/O channels. The processor is an Intel 80C196KC 16-bit microcontroller running at 20MHz on an 8-bit bus. This processor executes an interrupt-driven, scheduler-based software system written in C and assembled into an EPROM with user-accessible variables stored in NVSRAM. Under normal operation, velocity update requests arrive at 100Hz from the position-loop servo process running independently on the antenna computer. A variety of telescope safety checks are performed at 279Hz including routine servicing of a 6 millisecond watchdog timer. Additional ADCs onboard the microcontroller monitor the winding temperature and current in the brushless three-phase drive motors. The PID servo gains can be dynamically changed in software. Calibration factors and software filters can be applied to the tachometer readings prior to the application of

  14. An optimal control strategy for two-dimensional motion camouflage with non-holonimic constraints.

    Science.gov (United States)

    Rañó, Iñaki

    2012-07-01

    Motion camouflage is a stealth behaviour observed both in hover-flies and in dragonflies. Existing controllers for mimicking motion camouflage generate this behaviour on an empirical basis or without considering the kinematic motion restrictions present in animal trajectories. This study summarises our formal contributions to solve the generation of motion camouflage as a non-linear optimal control problem. The dynamics of the system capture the kinematic restrictions to motion of the agents, while the performance index ensures camouflage trajectories. An extensive set of simulations support the technique, and a novel analysis of the obtained trajectories contributes to our understanding of possible mechanisms to obtain sensor based motion camouflage, for instance, in mobile robots.

  15. Behavioral methods of alleviating motion sickness: effectiveness of controlled breathing and a music audiotape.

    Science.gov (United States)

    Yen Pik Sang, Fleur D; Billar, Jessica P; Golding, John F; Gresty, Michael A

    2003-01-01

    Behavioral countermeasures for motion sickness would be advantageous because of the side effects of antiemetic drugs, but few alternative treatments are available. The objective of this study was to compare the effectiveness of controlling breathing and listening to a music audiotape designed to reduce motion sickness symptoms, on increasing tolerance to motion-induced nausea. Twenty-four healthy subjects were exposed to nauseogenic Coriolis stimulation on a rotating turntable under three conditions: whilst focusing on controlling breathing; listening to a music audiotape; or without intervention (control). The three conditions were performed by each subject according to a replicated factorial design at 1-week intervals at the same time of day. Ratings of motion sickness were obtained every 30 seconds. Once a level of mild nausea was reached subjects commenced controlling breathing or listened to the music audiotape. Motion was stopped after the onset of moderate nausea. Mean (+/- SD) motion exposure time in minutes tolerated before the onset of moderate nausea was significantly longer (p music (10.4 +/- 5.6 min) compared with control (9.2 +/- 5.9 min). Both controlling breathing and the music audiotape provided significant protection against motion sickness and with similar effectiveness. These nonpharmacologic countermeasures are only half as effective as standard doses of anti-motion sickness drugs, such as oral scopolamine; however, they are easy to implement and free of side effects.

  16. Stirling engine power control and motion conversion mechanism

    Science.gov (United States)

    Marks, David T.

    1983-01-01

    A motion conversion device for converting between the reciprocating motion of the pistons in a Stirling engine and the rotating motion of its output shaft, and for changing the stroke and phase of the pistons, includes a lever pivoted at one end and having a cam follower at the other end. The piston rod engages the lever intermediate its ends and the cam follower engages a cam keyed to the output shaft. The lever pivot can be moved to change the length of the moment arm defined between the cam follower and the piston rod the change the piston stroke and force exerted on the cam, and the levers can be moved in opposite directions to change the phase between pistons.

  17. Optimal control of a programmed motion of a rigid spacecraft using redundant kinematics parameterizations

    International Nuclear Information System (INIS)

    El-Gohary, Awad

    2005-01-01

    This paper considers the problem of optimal controlling of a programmed motion of a rigid spacecraft. Given a cost of the spacecraft as a quadratic function of state and control variables we seek for optimal control laws as functions of the state variables and the angle of programmed rotation that minimize this cost and asymptotically stabilize the required programmed motion. The stabilizing properties of the proposed controllers are proved using the optimal Liapunov techniques. Numerical simulation study is presented

  18. Design and Simulation of a PID Controller for Motion Control Systems

    Science.gov (United States)

    Hassan Abdullahi, Zakariyya; Danzomo, Bashir Ahmed; Suleiman Abdullahi, Zainab

    2018-04-01

    Motion control system plays important role in many industrial applications among which are in robot system, missile launching, positioning systems etc. However, the performance requirement for these applications in terms of high accuracy, high speed, insignificant or no overshoot and robustness have generated continuous challenges in the field of motion control system design and implementation. To compensate this challenge, a PID controller was design using mathematical model of a DC motor based on classical root-locus approach. The reason for adopting root locus design is to remodel the closed-loop response by putting the closed-loop poles of the system at desired points. Adding poles and zeros to the initial open-loop transfer function through the controller provide a way to transform the root locus in order to place the closed-loop poles at the required points. This process can also be used for discrete-time models. The Advantages of root locus over other methods is that, it gives the better way of pinpointing the parameters and can easily predict the fulfilment of the whole system. The controller performance was simulated using MATLAB code and a reasonable degree of accuracy was obtained. Implementation of the proposed model was conducted using-Simulink and the result obtained shows that the PID controller met the transient performance specifications with both settling time and overshoot less than 0.1s and 5% respectively. In terms of steady state error, the PID controller gave good response for both step input and ramp.

  19. Changes in pilot control behaviour across Stewart platform motion systems

    NARCIS (Netherlands)

    Nieuwenhuizen, F.M.

    2012-01-01

    Flight simulators provide an effective, efficient, and safe environment for practising flight-critical manoeuvres without requiring a real aircraft. Most simulators are equipped with a Stewart-type motion system, which consists of six linear actuators in a hexapod configuration. The argument for use

  20. Robust motion control of oscillatory-base manipulators h∞-control and sliding-mode-control-based approaches

    CERN Document Server

    Toda, Masayoshi

    2016-01-01

    This book provides readers with alternative robust approaches to control design for an important class of systems characteristically associated with ocean-going vessels and structures. These systems, which include crane vessels, on-board cranes, radar gimbals, and a conductivity temperature and depth winch, are modelled as manipulators with oscillating bases. One design approach is based on the H-infinity control framework exploiting an effective combination of PD control, an extended matrix polytope and a robust stability analysis method with a state-dependent coefficient form. The other is based on sliding-mode control using some novel nonlinear sliding surfaces. The model demonstrates how successful motion control can be achieved by suppressing base oscillations and in the presence of uncertainties. This is important not only for ocean engineering systems in which the problems addressed here originate but more generally as a benchmark platform for robust motion control with disturbance rejection. Researche...

  1. Fractional order differentiation and robust control design crone, h-infinity and motion control

    CERN Document Server

    Sabatier, Jocelyn; Melchior, Pierre; Oustaloup, Alain

    2015-01-01

    This monograph collates the past decade’s work on fractional models and fractional systems in the fields of analysis, robust control and path tracking. Themes such as PID control, robust path tracking design and motion control methodologies involving fractional differentiation are amongst those explored. It juxtaposes recent theoretical results at the forefront in the field, and applications that can be used as exercises that will help the reader to assimilate the proposed methodologies. The first part of the book deals with fractional derivative and fractional model definitions, as well as recent results for stability analysis, fractional model physical interpretation, controllability, and H-infinity norm computation. It also presents a critical point of view on model pseudo-state and “real state”, tackling the problem of fractional model initialization. Readers will find coverage of PID, Fractional PID and robust control in the second part of the book, which rounds off with an extension of H-infinity ...

  2. Analysis of the Accuracy and Robustness of the Leap Motion Controller

    OpenAIRE

    Weichert, Frank; Bachmann, Daniel; Rudak, Bartholomäus; Fisseler, Denis

    2013-01-01

    The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pe...

  3. Linear motion device and method for inserting and withdrawing control rods

    International Nuclear Information System (INIS)

    Smith, J. E.

    1984-01-01

    A linear motion device, more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core, is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism

  4. Dynamics and Control of Underwater Gliders I: Steady Motions

    OpenAIRE

    Mahmoudian, N.; Geisbert, J.; Woolsey, C.

    2007-01-01

    This paper describes analysis of steady motions for underwater gliders, a type of highly efficient underwater vehicle which uses gravity for propulsion. Underwater gliders are winged underwater vehicles which locomote by modulating their buoyancy and their attitude. Several such vehicles have been developed and have proven their worth as efficient long-distance, long-duration ocean sampling platforms. To date, the primary emphasis in underwater glider development has been on locomotive effici...

  5. A Hybrid Scheme Motion Controller by Sliding Mode and Two-Degree-of-Freedom Controls to Minimize the Chattering

    Directory of Open Access Journals (Sweden)

    Chiu-Keng Lai

    2014-01-01

    Full Text Available Sliding mode control (SMC is rapped for the chattering due to high gain control. However, high gain control causes the system robust. For developing a system with robustness of SMC, a servo motor motion controller combining the two-degree-of-freedom (2DOF system and SMC is proposed. The discussed motion type is point-to-point control with the constraint of trapezoid velocity profile. SMC is designed to guide the motor motion to follow a predefined trail, and the inner 2DOF system is used to compensate the deterioration due to the adoption of load observer. The proposed hybrid system is realized on a PC-based motion controller, and the validness is verified by simulation and experimental results.

  6. Oil Motion Control by an Extra Pinning Structure in Electro-Fluidic Display.

    Science.gov (United States)

    Dou, Yingying; Tang, Biao; Groenewold, Jan; Li, Fahong; Yue, Qiao; Zhou, Rui; Li, Hui; Shui, Lingling; Henzen, Alex; Zhou, Guofu

    2018-04-06

    Oil motion control is the key for the optical performance of electro-fluidic displays (EFD). In this paper, we introduced an extra pinning structure (EPS) into the EFD pixel to control the oil motion inside for the first time. The pinning structure canbe fabricated together with the pixel wall by a one-step lithography process. The effect of the relative location of the EPS in pixels on the oil motion was studied by a series of optoelectronic measurements. EPS showed good control of oil rupture position. The properly located EPS effectively guided the oil contraction direction, significantly accelerated switching on process, and suppressed oil overflow, without declining in aperture ratio. An asymmetrically designed EPS off the diagonal is recommended. This study provides a novel and facile way for oil motion control within an EFD pixel in both direction and timescale.

  7. Robust Control and Motion Planning for Nonlinear Underactuated Systems Using H infinity Techniques

    National Research Council Canada - National Science Library

    Toussaint, Gregory

    2000-01-01

    This thesis presents new techniques for planning and robustly controlling the motion of nonlinear underactuated vehicles when disturbances are present and only imperfect state measurements are available for feedback...

  8. Optimization of motion control laws for tether crawler or elevator systems

    Science.gov (United States)

    Swenson, Frank R.; Von Tiesenhausen, Georg

    1988-01-01

    Based on the proposal of a motion control law by Lorenzini (1987), a method is developed for optimizing motion control laws for tether crawler or elevator systems in terms of the performance measures of travel time, the smoothness of acceleration and deceleration, and the maximum values of velocity and acceleration. The Lorenzini motion control law, based on powers of the hyperbolic tangent function, is modified by the addition of a constant-velocity section, and this modified function is then optimized by parameter selections to minimize the peak acceleration value for a selected travel time or to minimize travel time for the selected peak values of velocity and acceleration. It is shown that the addition of a constant-velocity segment permits further optimization of the motion control law performance.

  9. Mathematical models of decision making on space vehicle motion control at fuzzy conditions

    International Nuclear Information System (INIS)

    Arslanov, M.Z.; Ismail, E.E.; Oryspaev, D.O.

    2005-01-01

    the structure of decision making for control of spacecraft motion is considered. Mathematical models of decision making problems are investigated. New methods of criteria convolution are received. New convolution have properties of smoothness. (author)

  10. Robust motion control design for dual-axis motion platform using ...

    Indian Academy of Sciences (India)

    control for the multi-axis systems has attracted much attention. As an ... mechanisms interact under different environmental conditions. ...... Subbu R, Goebel K, Frederick D K 2005 Evolutionary design and optimization of aircraft engine.

  11. Autogenic-feedback training exercise is superior to promethazine for control of motion sickness symptoms

    Science.gov (United States)

    Cowings, P. S.; Toscano, W. B.

    2000-01-01

    Motion sickness symptoms affect approximately 50% of the crew during space travel and are commonly treated with intramuscular injections of promethazine. The purpose of this paper is to compare the effectiveness of three treatments for motion sickness: intramuscular injections (i.m.) of promethazine, a physiological training method (autogenic-feedback training exercise [AFTE]), and a no-treatment control. An earlier study tested the effects of promethazine on cognitive and psychomotor performance and motion sickness tolerance in a rotating chair. For the present paper, motion sickness tolerance, symptom reports, and physiological responses of these subjects were compared to matched subjects selected from an existing database who received either AFTE or no treatment. Three groups of 11 men, between the ages of 33 and 40 years, were matched on the number of rotations tolerated during their initial rotating-chair motion sickness test. The motion sickness test procedures and the 7-day interval between tests were the same for all subjects. The drug group was tested under four treatment conditions: baseline (no injections), a 25 mg dose of promethazine, a 50 mg dose of promethazine, and a placebo of sterile saline. AFTE subjects were given four 30-minute AFTE sessions before their second, third, and fourth motion sickness tests (6 hours total). The no-treatment control subjects were only given the four rotating-chair tests. Motion sickness tolerance was significantly increased after 4 hours of AFTE when compared to either 25 mg (p training.

  12. Using Unconstrained Tongue Motion as an Alternative Control Mechanism for Wheeled Mobility

    OpenAIRE

    Huo, Xueliang; Ghovanloo, Maysam

    2009-01-01

    Tongue drive system (TDS) is a tongue-operated, minimally invasive, unobtrusive, noncontact, and wireless assistive technology that infers users’ intentions by detecting and classifying their voluntary tongue motions, and translating them to user-defined commands. We have developed customized interface circuitry between an external TDS (eTDS) prototype and a commercial powered wheelchair (PWC) as well as three control strategies to evaluate the tongue motion as an alternative control input fo...

  13. Hand Motion-Based Remote Control Interface with Vibrotactile Feedback for Home Robots

    Directory of Open Access Journals (Sweden)

    Juan Wu

    2013-06-01

    Full Text Available This paper presents the design and implementation of a hand-held interface system for the locomotion control of home robots. A handheld controller is proposed to implement hand motion recognition and hand motion-based robot control. The handheld controller can provide a ‘connect-and-play’ service for the users to control the home robot with visual and vibrotactile feedback. Six natural hand gestures are defined for navigating the home robots. A three-axis accelerometer is used to detect the hand motions of the user. The recorded acceleration data are analysed and classified to corresponding control commands according to their characteristic curves. A vibration motor is used to provide vibrotactile feedback to the user when an improper operation is performed. The performances of the proposed hand motion-based interface and the traditional keyboard and mouse interface have been compared in robot navigation experiments. The experimental results of home robot navigation show that the success rate of the handheld controller is 13.33% higher than the PC based controller. The precision of the handheld controller is 15.4% more than that of the PC and the execution time is 24.7% less than the PC based controller. This means that the proposed hand motion-based interface is more efficient and flexible.

  14. The 3D Human Motion Control Through Refined Video Gesture Annotation

    Science.gov (United States)

    Jin, Yohan; Suk, Myunghoon; Prabhakaran, B.

    In the beginning of computer and video game industry, simple game controllers consisting of buttons and joysticks were employed, but recently game consoles are replacing joystick buttons with novel interfaces such as the remote controllers with motion sensing technology on the Nintendo Wii [1] Especially video-based human computer interaction (HCI) technique has been applied to games, and the representative game is 'Eyetoy' on the Sony PlayStation 2. Video-based HCI technique has great benefit to release players from the intractable game controller. Moreover, in order to communicate between humans and computers, video-based HCI is very crucial since it is intuitive, easy to get, and inexpensive. On the one hand, extracting semantic low-level features from video human motion data is still a major challenge. The level of accuracy is really dependent on each subject's characteristic and environmental noises. Of late, people have been using 3D motion-capture data for visualizing real human motions in 3D space (e.g, 'Tiger Woods' in EA Sports, 'Angelina Jolie' in Bear-Wolf movie) and analyzing motions for specific performance (e.g, 'golf swing' and 'walking'). 3D motion-capture system ('VICON') generates a matrix for each motion clip. Here, a column is corresponding to a human's sub-body part and row represents time frames of data capture. Thus, we can extract sub-body part's motion only by selecting specific columns. Different from low-level feature values of video human motion, 3D human motion-capture data matrix are not pixel values, but is closer to human level of semantics.

  15. Predictive piston motion control in a free-piston internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Mikalsen, R.; Jones, E.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU England (United Kingdom)

    2010-05-15

    A piston motion controller for a free-piston internal combustion engine is presented. To improve dynamic performance in the control of the piston motion and engine compression ratio, the controller response is determined from a prediction of engine top dead centre error rather than the measured value from the previous cycle. The proposed control approach showed superior performance compared with that of standard PI feedback control known from the literature due to a reduced control action time delay. The manipulation of fuel injection timing to reduce in-cylinder pressure peaks and cycle-to-cycle variations was also studied, indicating that with the piston motion estimation, the injection timing is a powerful control variable for this purpose. (author)

  16. Motion Normalized Proportional Control for Improved Pattern Recognition-Based Myoelectric Control.

    Science.gov (United States)

    Scheme, Erik; Lock, Blair; Hargrove, Levi; Hill, Wendy; Kuruganti, Usha; Englehart, Kevin

    2014-01-01

    This paper describes two novel proportional control algorithms for use with pattern recognition-based myoelectric control. The systems were designed to provide automatic configuration of motion-specific gains and to normalize the control space to the user's usable dynamic range. Class-specific normalization parameters were calculated using data collected during classifier training and require no additional user action or configuration. The new control schemes were compared to the standard method of deriving proportional control using a one degree of freedom Fitts' law test for each of the wrist flexion/extension, wrist pronation/supination and hand close/open degrees of freedom. Performance was evaluated using the Fitts' law throughput value as well as more descriptive metrics including path efficiency, overshoot, stopping distance and completion rate. The proposed normalization methods significantly outperformed the incumbent method in every performance category for able bodied subjects (p < 0.001) and nearly every category for amputee subjects. Furthermore, one proposed method significantly outperformed both other methods in throughput (p < 0.0001), yielding 21% and 40% improvement over the incumbent method for amputee and able bodied subjects, respectively. The proposed control schemes represent a computationally simple method of fundamentally improving myoelectric control users' ability to elicit robust, and controlled, proportional velocity commands.

  17. Motion control for a walking companion robot with a novel human–robot interface

    Directory of Open Access Journals (Sweden)

    Yunqi Lv

    2016-09-01

    Full Text Available A walking companion robot is presented for rehabilitation from dyskinesia of lower limbs in this article. A new human–robot interface (HRI is designed which adopts one-axis force sensor and potentiometer connector to detect the motion of the user. To accompany in displacement and angle between the user and the robot precisely in real time, the common motions are classified into two elemental motion states. With distinction method of motion states, a classification scheme of motion control is adopted. The mathematical model-based control method is first introduced and the corresponding control systems are built. Due to the unavoidable deviation of the mathematical model-based control method, a force control method is proposed and the corresponding control systems are built. The corresponding simulations demonstrate that the efficiency of the two proposed control methods. The experimental data and paths of robot verify the two control methods and indicate that the force control method can better satisfy the user’s requirements.

  18. Development of an Embedded Solar Tracking System with LabVIEW Motion Control

    International Nuclear Information System (INIS)

    Oh, Seung Jin; Hyun, Jun Ho; Oh, Won Jong; Kim, Yeong Min; Lee, Yoon Joon; Chun, Won Gee

    2010-01-01

    Motion control is a sub-field of automation, in which the position and/or velocity of machines are controlled using some type of device such as a hydraulic pump, linear actuator, or an electric motor. The motion control is widely used in the packaging, printing, textile, semiconductor production, and power plants. National Instruments LabVIEW is a graphical programming language that has its roots in automation control and data acquisition. Its graphical representation, similar to a process flow diagram, was created to provide an intuitive programming environment for scientist and engineers. Crystal River Nuclear Plant engineers developed automated testing system of nuclear plant control modules in an aging nuclear power plant using LabVIEW to improve performance and reliability and reduce cost. In this study, an embedded two-axis solar tracking system was developed using LabVIEW motion control module

  19. Inhibitory Control of Feature Selectivity in an Object Motion Sensitive Circuit of the Retina

    Directory of Open Access Journals (Sweden)

    Tahnbee Kim

    2017-05-01

    Full Text Available Object motion sensitive (OMS W3-retinal ganglion cells (W3-RGCs in mice respond to local movements in a visual scene but remain silent during self-generated global image motion. The excitatory inputs that drive responses of W3-RGCs to local motion were recently characterized, but which inhibitory neurons suppress W3-RGCs’ responses to global motion, how these neurons encode motion information, and how their connections are organized along the excitatory circuit axis remains unknown. Here, we find that a genetically identified amacrine cell (AC type, TH2-AC, exhibits fast responses to global motion and slow responses to local motion. Optogenetic stimulation shows that TH2-ACs provide strong GABAA receptor-mediated input to W3-RGCs but only weak input to upstream excitatory neurons. Cell-type-specific silencing reveals that temporally coded inhibition from TH2-ACs cancels W3-RGC spike responses to global but not local motion stimuli and, thus, controls the feature selectivity of OMS signals sent to the brain.

  20. Motion control system of MAX IV Laboratory soft x-ray beamlines

    International Nuclear Information System (INIS)

    Sjöblom, Peter; Lindberg, Mirjam; Forsberg, Johan; Persson, Andreas G.; Urpelainen, Samuli; Såthe, Conny

    2016-01-01

    At the MAX IV Laboratory, five new soft x-ray beamlines are under development. The first is Species and it will be used to develop and set the standard of the control system, which will be common across the facility. All motion axes at MAX IV will be motorized using stepper motors steered by the IcePAP motion controller and a mixture of absolute and incremental encoders following a predefined coordinate system. The control system software is built in Tango and uses the Python-based Sardana framework. The user controls the entire beamline through a synoptic overview and Sardana is used to run the scans.

  1. Three axis electronic flight motion simulator real time control system design and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiyuan; Miao, Zhonghua, E-mail: zhonghua-miao@163.com; Wang, Xiaohua [School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200072 (China); Wang, Xuyong [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2014-12-15

    A three axis electronic flight motion simulator is reported in this paper including the modelling, the controller design as well as the hardware implementation. This flight motion simulator could be used for inertial navigation test and high precision inertial navigation system with good dynamic and static performances. A real time control system is designed, several control system implementation problems were solved including time unification with parallel port interrupt, high speed finding-zero method of rotary inductosyn, zero-crossing management with continuous rotary, etc. Tests were carried out to show the effectiveness of the proposed real time control system.

  2. Three axis electronic flight motion simulator real time control system design and implementation.

    Science.gov (United States)

    Gao, Zhiyuan; Miao, Zhonghua; Wang, Xuyong; Wang, Xiaohua

    2014-12-01

    A three axis electronic flight motion simulator is reported in this paper including the modelling, the controller design as well as the hardware implementation. This flight motion simulator could be used for inertial navigation test and high precision inertial navigation system with good dynamic and static performances. A real time control system is designed, several control system implementation problems were solved including time unification with parallel port interrupt, high speed finding-zero method of rotary inductosyn, zero-crossing management with continuous rotary, etc. Tests were carried out to show the effectiveness of the proposed real time control system.

  3. Nonlinear Model Predictive Control of a Cable-Robot-Based Motion Simulator

    DEFF Research Database (Denmark)

    Katliar, Mikhail; Fischer, Joerg; Frison, Gianluca

    2017-01-01

    In this paper we present the implementation of a model-predictive controller (MPC) for real-time control of a cable-robot-based motion simulator. The controller computes control inputs such that a desired acceleration and angular velocity at a defined point in simulator's cabin are tracked while...... satisfying constraints imposed by working space and allowed cable forces of the robot. In order to fully use the simulator capabilities, we propose an approach that includes the motion platform actuation in the MPC model. The tracking performance and computation time of the algorithm are investigated...

  4. Motion control system of MAX IV Laboratory soft x-ray beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Sjöblom, Peter, E-mail: peter.sjoblom@maxlab.lu.se; Lindberg, Mirjam, E-mail: mirjam.lindberg@maxlab.lu.se; Forsberg, Johan, E-mail: johan.forsberg@maxlab.lu.se; Persson, Andreas G., E-mail: andreas-g.persson@maxlab.lu.se; Urpelainen, Samuli, E-mail: samuli.urpelainen@maxlab.lu.se; Såthe, Conny, E-mail: conny.sathe@maxlab.lu.se [MAX IV Laboratory, Photongatan 2, 225 92 Lund (Sweden)

    2016-07-27

    At the MAX IV Laboratory, five new soft x-ray beamlines are under development. The first is Species and it will be used to develop and set the standard of the control system, which will be common across the facility. All motion axes at MAX IV will be motorized using stepper motors steered by the IcePAP motion controller and a mixture of absolute and incremental encoders following a predefined coordinate system. The control system software is built in Tango and uses the Python-based Sardana framework. The user controls the entire beamline through a synoptic overview and Sardana is used to run the scans.

  5. Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

    Science.gov (United States)

    Lyons, Elizabeth J.; Tate, Deborah F.; Ward, Dianne S.; Ribisl, Kurt M.; Bowling, J. Michael; Kalyanaraman, Sriram

    2012-01-01

    Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg−1 · hr−1) produced 0.10 kcal · kg−1 · hr−1 (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg−1 · hr−1, P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior. PMID:22028959

  6. Do Motion Controllers Make Action Video Games Less Sedentary? A Randomized Experiment

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Lyons

    2012-01-01

    Full Text Available Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100 were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12. An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal ⋅ kg-1 ⋅ hr-1 produced 0.10 kcal ⋅ kg-1 ⋅ hr-1 (95% confidence interval 0.03 to 0.17 greater energy expenditure than traditional control (0.86 [0.17] kcal ⋅ kg-1 ⋅ hr-1, P = .048. All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior.

  7. Do motion controllers make action video games less sedentary? A randomized experiment.

    Science.gov (United States)

    Lyons, Elizabeth J; Tate, Deborah F; Ward, Dianne S; Ribisl, Kurt M; Bowling, J Michael; Kalyanaraman, Sriram

    2012-01-01

    Sports- and fitness-themed video games using motion controllers have been found to produce physical activity. It is possible that motion controllers may also enhance energy expenditure when applied to more sedentary games such as action games. Young adults (N = 100) were randomized to play three games using either motion-based or traditional controllers. No main effect was found for controller or game pair (P > .12). An interaction was found such that in one pair, motion control (mean [SD] 0.96 [0.20] kcal · kg(-1) · hr(-1)) produced 0.10 kcal · kg(-1) · hr(-1) (95% confidence interval 0.03 to 0.17) greater energy expenditure than traditional control (0.86 [0.17] kcal · kg(-1) · hr(-1), P = .048). All games were sedentary. As currently implemented, motion control is unlikely to produce moderate intensity physical activity in action games. However, some games produce small but significant increases in energy expenditure, which may benefit health by decreasing sedentary behavior.

  8. Research and development of a control system for multi axis cooperative motion based on PMAC

    Science.gov (United States)

    Guo, Xiao-xiao; Dong, Deng-feng; Zhou, Wei-hu

    2017-10-01

    Based on Programmable Multi-axes Controller (PMAC), a design of a multi axis motion control system for the simulator of spatial targets' dynamic optical properties is proposed. According to analysis the properties of spatial targets' simulator motion control system, using IPC as the main control layer, TurboPMAC2 as the control layer to meet coordinated motion control, data acquisition and analog output. A simulator using 5 servomotors which is connected with speed reducers to drive the output axis was implemented to simulate the motion of both the sun and the space target. Based on PMAC using PID and a notch filter algorithm, negative feedback, the speed and acceleration feed forward algorithm to satisfy the axis' requirements of the good stability and high precision at low speeds. In the actual system, it shows that the velocity precision is higher than 0.04 s ° and the precision of repetitive positioning is better than 0.006° when each axis is at a low-speed. Besides, the system achieves the control function of multi axis coordinated motion. The design provides an important technical support for detecting spatial targets, also promoting the theoretical research.

  9. Randomness control of vehicular motion through a sequence of traffic signals at irregular intervals

    International Nuclear Information System (INIS)

    Nagatani, Takashi

    2010-01-01

    We study the regularization of irregular motion of a vehicle moving through the sequence of traffic signals with a disordered configuration. Each traffic signal is controlled by both cycle time and phase shift. The cycle time is the same for all signals, while the phase shift varies from signal to signal by synchronizing with intervals between a signal and the next signal. The nonlinear dynamic model of the vehicular motion is presented by the stochastic nonlinear map. The vehicle exhibits the very complex behavior with varying both cycle time and strength of irregular intervals. The irregular motion induced by the disordered configuration is regularized by adjusting the phase shift within the regularization regions.

  10. Modification of Motion Perception and Manual Control Following Short-Durations Spaceflight

    Science.gov (United States)

    Wood, S. J.; Vanya, R. D.; Esteves, J. T.; Rupert, A. H.; Clement, G.

    2011-01-01

    Adaptive changes during space flight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination and spatial disorientation following G-transitions. This ESA-NASA study was designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances following short-duration spaceflights. The goals of this study were to (1) examine the effects of stimulus frequency on adaptive changes in motion perception during passive tilt and translation motion, (2) quantify decrements in manual control of tilt motion, and (3) evaluate vibrotactile feedback as a sensorimotor countermeasure.

  11. Autogenic Feedback Training Exercise: Controlling Physiological Responses to Mitigate Motion Sickness

    Science.gov (United States)

    Walton, Nia; Spencer, Telissa; Cowings, Patricia; Toscano, William B.

    2018-01-01

    During space travel approximately 50 of the crew experience symptoms of motion sickness that can range from mild forms of nausea or dizziness to severe malaise and vomiting1. Developing an effective treatment for these symptoms has become a priority of the National Aeronautics and Space Administration (NASA). Autogenic-Feedback Training Exercise (AFTE) is a nonpharmacological countermeasure for mitigating motion sickness. It involves training subjects to control physiological responses in high stress environments2. The primary goal of this experiment is to evaluate the effectiveness of AFTE for increasing tolerance to motion sickness in high stress environments.

  12. Enhancement of vortex induced forces and motion through surface roughness control

    Science.gov (United States)

    Bernitsas, Michael M [Saline, MI; Raghavan, Kamaldev [Houston, TX

    2011-11-01

    Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to increase Vortex Induced Forces and Motion. Enhancement is needed in such applications as harnessing of clean and renewable energy from ocean/river currents using the ocean energy converter VIVACE (Vortex Induced Vibration for Aquatic Clean Energy).

  13. Reduction of vortex induced forces and motion through surface roughness control

    Science.gov (United States)

    Bernitsas, Michael M; Raghavan, Kamaldev

    2014-04-01

    Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to decrease/suppress Vortex Induced Forces and Motion. Suppression is required when fluid-structure interaction becomes destructive as in VIM of flexible cylinders or rigid cylinders on elastic support, such as underwater pipelines, marine risers, tubes in heat exchangers, nuclear fuel rods, cooling towers, SPAR offshore platforms.

  14. Coordinated joint motion control system with position error correction

    Science.gov (United States)

    Danko, George L.

    2016-04-05

    Disclosed are an articulated hydraulic machine supporting, control system and control method for same. The articulated hydraulic machine has an end effector for performing useful work. The control system is capable of controlling the end effector for automated movement along a preselected trajectory. The control system has a position error correction system to correct discrepancies between an actual end effector trajectory and a desired end effector trajectory. The correction system can employ one or more absolute position signals provided by one or more acceleration sensors supported by one or more movable machine elements. Good trajectory positioning and repeatability can be obtained. A two joystick controller system is enabled, which can in some cases facilitate the operator's task and enhance their work quality and productivity.

  15. Range-Space Predictive Control for Optimal Robot Motion

    Czech Academy of Sciences Publication Activity Database

    Belda, Květoslav; Böhm, Josef

    2008-01-01

    Roč. 1, č. 1 (2008), s. 1-7 ISSN 1998-0140 R&D Projects: GA ČR GP102/06/P275 Institutional research plan: CEZ:AV0Z10750506 Keywords : Accurate manipulation * Industrial robotics * Predictive control * Range-space control Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/historie/belda-0305644.pdf

  16. Maximum Principle for General Controlled Systems Driven by Fractional Brownian Motions

    International Nuclear Information System (INIS)

    Han Yuecai; Hu Yaozhong; Song Jian

    2013-01-01

    We obtain a maximum principle for stochastic control problem of general controlled stochastic differential systems driven by fractional Brownian motions (of Hurst parameter H>1/2). This maximum principle specifies a system of equations that the optimal control must satisfy (necessary condition for the optimal control). This system of equations consists of a backward stochastic differential equation driven by both fractional Brownian motions and the corresponding underlying standard Brownian motions. In addition to this backward equation, the maximum principle also involves the Malliavin derivatives. Our approach is to use conditioning and Malliavin calculus. To arrive at our maximum principle we need to develop some new results of stochastic analysis of the controlled systems driven by fractional Brownian motions via fractional calculus. Our approach of conditioning and Malliavin calculus is also applied to classical system driven by standard Brownian motions while the controller has only partial information. As a straightforward consequence, the classical maximum principle is also deduced in this more natural and simpler way.

  17. Linear motion device and method for inserting and withdrawing control rods

    Science.gov (United States)

    Smith, J.E.

    Disclosed is a linear motion device and more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core. The CRDM and method disclosed is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.

  18. Analysis of the accuracy and robustness of the leap motion controller.

    Science.gov (United States)

    Weichert, Frank; Bachmann, Daniel; Rudak, Bartholomäus; Fisseler, Denis

    2013-05-14

    The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pen allowing a position accuracy of 0.2 mm. Thereby, a deviation between a desired 3D position and the average measured positions below 0.2 mm has been obtained for static setups and of 1.2 mm for dynamic setups. Using the conclusion of this analysis can improve the development of applications for the Leap Motion controller in the field of Human-Computer Interaction.

  19. Analysis of the Accuracy and Robustness of the Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Denis Fisseler

    2013-05-01

    Full Text Available The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pen allowing a position accuracy of 0.2 mm. Thereby, a deviation between a desired 3D position and the average measured positions below 0.2mmhas been obtained for static setups and of 1.2mmfor dynamic setups. Using the conclusion of this analysis can improve the development of applications for the Leap Motion controller in the field of Human-Computer Interaction.

  20. Experimental Study on Position Control System Using Encoderless Magnetic Motion

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Youn; Heo, Hoon [Korea Univ., Seoul (Korea, Republic of); Yun, Young Min; Shim, Ho Keun; Kwon, Young Mok [TPC Mechatronics, Daejeon (Korea, Republic of)

    2016-01-15

    A position control system composed of the PMLSM(Permanent Magnet Linear Synchronous Motor), unlike conventional linear permanent magnet synchronous motor is fixed to the permanent magnet moving coil rails (permanent magnet = stator, coil = mover), the coil is fixed, moving the permanent magnet, we propose a position control system (permanent magnet = mover, coil = stator) structure. Position is measured not using conventional encoder or resolver but by adopting vector control method using 2 hall sensors generating rectangular signal. This method estimate the velocity and position of mover by using the quadruple of two hall sensor signal instead of encoder signal. Vector control of PMLSM using 2 hall sensor generating rectangular wave is proved to control the system stable and efficiently through simulation. Also hardware experiment reveals that the position control performance is measured within the range of 30-50μ in the accuracy of 10-20μ, which is improved twice to the conventional method. The proposed method exhibits its economical efficiency and practical usefulness. The vector control technique using two hall sensors can be installed in narrow place, accordingly it can be implemented on the system where the conventional encoder or resolver cannot operate.

  1. How NASA KSC Controls Interfaces with the use of Motion Skeletons and Product Structure

    Science.gov (United States)

    Jones, Corey

    2013-01-01

    This presentation will show how NASA KSC controls interfaces for Modular Product Architecture (MPA) using Locator Skeletons, Interface Skeletons, and Product Structure, to be combined together within a Motion Skeleton. The user will learn how to utilize skeleton models to communicate interface data, as successfully done at NASA KSC in their use of Motion Skeletons to control interfaces for multi-launch systems. There will be discussion of the methodology used to control design requirements through WTParts, and how to utilize product structure for non-CAD documents.

  2. Development of an FPGA-Based Motion Control IC for Caving Machine

    Directory of Open Access Journals (Sweden)

    Chiu-Keng Lai

    2014-03-01

    Full Text Available Since the Field Programmable Gate Arrays (FPGAs with high density are available nowadays, systems with complex functions can thus be realized by FPGA in a single chip while they are traditionally implemented by several individual chips. In this research, the control of stepping motor drives as well as motion controller is integrated and implemented on Altera Cyclone III FPGA; the resulting system is evaluated by applying it to a 3-axis caving machine which is driven by stepping motors. Finally, the experimental results of current regulation and motion control integrated in FPGA IC are shown to prove the validness.

  3. Modification of hemiplegic compensatory gait pattern by symmetry-based motion controller of HAL.

    Science.gov (United States)

    Kawamoto, Hiroaki; Kadone, Hideki; Sakurai, Takeru; Sankai, Yoshiyuki

    2015-01-01

    As one of several characteristics of hemiplegic patients after stroke, compensatory gait caused by affected limb is often seen. The purpose of this research is to apply a symmetry-based controller of a wearable type lower limb robot, Hybrid Assistive Limb (HAL) to hemiplegic patients with compensatory gait, and to investigate improvement of gait symmetry. The controller is designed respectively for swing phase and support phase according to characteristics of hemiplegic gait pattern. The controller during swing phase stores the motion of the unaffected limb and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. Moreover, the controller during support phase provides motion to extend hip and knee joints to support wearer's body. Clinical tests were conducted in order to assess the modification of gait symmetry. Our case study involved participation of one chronic stroke patient who performs abnormally-compensatory gait for both of the affected and unaffected limbs. As a result, the patient's gait symmetry was improved by providing motion support during the swing phase on the affected side and motion constraint during the support phase on the unaffected side. The study showed promising basis for the effectiveness of the controller for the future clinical study.

  4. POSTURAL CONTROL IN HEALTHY YOUNG ADULTS WITH AND WITHOUT CHRONIC MOTION SENSITIVITY

    Directory of Open Access Journals (Sweden)

    Alyahya D

    2016-02-01

    Full Text Available Background: Postural control requires complex processing of peripheral sensory inputs from the visual, somatosensory and vestibular systems. Motion sensitivity and decreased postural control are influenced by visual-vestibular conflicts.The purpose of this study was to measure the difference between the postural control of healthy adults with and without history of sub-clinical chronic motion sensitivity using a computerized dynamic posturography in a virtual reality environment. Sub-clinical chronic motion sensitivity was operationally defined as a history of avoiding activities causing dizziness, nausea, imbalance, and/or blurred vision without having a related medical diagnosis. Methods: Twenty healthy adults between 22 and 33 years of age participated in the study. Eleven subjects had sub-clinical chronic motion sensitivity and 9 subjects did not. Postural control was measured in both groups using the Bertec Balance Advantage-Dynamic Computerized Dynamic Posturography with Immersion Virtual Reality (CDP-IVR. The CDP-IVR reports an over-all equilibrium score based on subjects’ center of gravity displacement and postural sway while immersed in a virtual reality environment. Subjects were tested on stable (condition 1 and unstable (condition2 platform conditions. Results: There was no significant difference between the two groups in terms of mean age, height, weight, body mass index in kg/m2, postural control scores for conditions 2, and average (p>0.05. However, significant differences were observed in mean postural control for condition 1 between groups (p=0.03. Conclusions: Results of this study suggest that healthy young adults without chronic sub-clinical motion sensitivity have better postural control than those with chronic sub-clinical motion sensitivity. Further investigation is warranted to explore wider age ranges with larger samples sizes as well as intervention strategies to improve postural control.

  5. Alternative Motion Control for Educational Biped BRAT Robots

    Directory of Open Access Journals (Sweden)

    Levente Barabas

    2015-12-01

    Full Text Available In this paper an alternative control solution will be proposed for an educational biped BRAT robot by replacing its SSC-32 servomotor controller with an Arduino R3 development board. Also we will be approaching the problem of adapting the existing electronic circuit to the new requirements and proposing a new application by adding an ultrasonic distance sensor in order to increase the versatility of the robot and make it capable to interact with its environment.

  6. Design of a linear-motion dual-stage actuation system for precision control

    International Nuclear Information System (INIS)

    Dong, W; Tang, J; ElDeeb, Y

    2009-01-01

    Actuators with high linear-motion speed, high positioning resolution and a long motion stroke are needed in many precision machining systems. In some current systems, voice coil motors (VCMs) are implemented for servo control. While the voice coil motors may provide the long motion stroke needed in many applications, the main obstacle that hinders the improvement of the machining accuracy and efficiency is their limited bandwidth. To fundamentally solve this issue, we propose to develop a dual-stage actuation system that consists of a voice coil motor that covers the coarse motion, and a piezoelectric stack actuator that induces the fine motion, thus enhancing the positioning accuracy. The focus of this present research is the mechatronics design and synthesis of the new actuation system. In particular, a flexure hinge based mechanism is developed to provide a motion guide and preload to the piezoelectric stack actuator that is serially connected to the voice coil motor. This mechanism is built upon parallel plane flexure hinges. A series of numerical and experimental studies are carried out to facilitate the system design and the model identification. The effectiveness of the proposed system is demonstrated through open-loop studies and preliminary closed-loop control practice. While the primary goal of this particular design is aimed at enhancing optical lens machining, the concept and approach outlined are generic and can be extended to a variety of applications

  7. Autogenic-Feedback Training for the Control of Space Motion Sickness

    Science.gov (United States)

    Cowings, Patricia S.; Toscano, W. B.

    1994-01-01

    This paper presents case-studies of 9 shuttle crewmembers (prime and alternates) and one U.S. Navy F-18 pilot, as they participated in all preflight training and testing activities in support of a life sciences flight experiment aboard Spacelab-J, and Spacelab-3. The primary objective of the flight experiment was to determine if Autogenic-feedback training (AFT), a physiological self-regulation training technique would be an effective treatment for motion sickness and space motion sickness in these crewmembers. Additional objectives of this study involved the examining human physiological responses to motion sickness on Earth and in space, as well as developing predictive criteria for susceptibility to space motion sickness based on ground-based data. Comparisons of these crewmembers are made to a larger set of subjects from previous experiments (treatment and "test-only" controls subjects). This paper describes all preflight methods, results and proposed changes for future tests.

  8. Differences in kinematic control of ankle joint motions in people with chronic ankle instability.

    Science.gov (United States)

    Kipp, Kristof; Palmieri-Smith, Riann M

    2013-06-01

    People with chronic ankle instability display different ankle joint motions compared to healthy people. The purpose of this study was to investigate the strategies used to control ankle joint motions between a group of people with chronic ankle instability and a group of healthy, matched controls. Kinematic data were collected from 11 people with chronic ankle instability and 11 matched control subjects as they performed a single-leg land-and-cut maneuver. Three-dimensional ankle joint angles were calculated from 100 ms before, to 200 ms after landing. Kinematic control of the three rotational ankle joint degrees of freedom was investigated by simultaneously examining the three-dimensional co-variation of plantarflexion/dorsiflexion, toe-in/toe-out rotation, and inversion/eversion motions with principal component analysis. Group differences in the variance proportions of the first two principal components indicated that the angular co-variation between ankle joint motions was more linear in the control group, but more planar in the chronic ankle instability group. Frontal and transverse plane motions, in particular, contributed to the group differences in the linearity and planarity of angular co-variation. People with chronic ankle instability use a different kinematic control strategy to coordinate ankle joint motions during a single-leg landing task. Compared to the healthy group, the chronic ankle instability group's control strategy appeared to be more complex and involved joint-specific contributions that would tend to predispose this group to recurring episodes of instability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Multi-robot motion control for cooperative observation

    International Nuclear Information System (INIS)

    Parker, L.E.

    1997-01-01

    An important issue that arises in the automation of many security, surveillance, and reconnaissance tasks is that of monitoring (or observing) the movements of targets navigating in a bounded area of interest. A key research issue in these problems is that of sensor placement--determining where sensors should be located to maintain the targets in view. In complex applications involving limited-range sensors, the use of multiple sensors dynamically moving over time is required. In this paper, the authors investigate the use of a cooperative team of autonomous sensor-based robots for the observation of multiple moving targets. They focus primarily on developing the distributed control strategies that allow the robot team to attempt to minimize the total time in which targets escape observation by some robot team member in the area of interest. This paper first formalizes the problem and discusses related work. The authors then present a distributed approximate approach to solving this problem that combines low-level multi-robot control with higher-level reasoning control based on the ALLIANCE formalism. They analyze the effectiveness of the approach by comparing it to 3 other feasible algorithms for cooperative control, showing the superiority of the approach for a large class of problems

  10. Cooperative motion control for multi-target observation

    International Nuclear Information System (INIS)

    Parker, L.E.

    1997-01-01

    An important issue that arises in the automation of many security, surveillance, and reconnaissance tasks is that of monitoring (or observing) the movements of targets navigating in a bounded area of interest. A key research issue in these problems is that of sensor placement--determining where sensors should be located to maintain the targets in view. In complex applications involving limited-range sensors, the use of multiple sensors dynamically moving over time is required. In this paper, the author investigates the use of a cooperative team of autonomous sensor-based robots for the observation of multiple moving targets. The focus is primarily on developing the distributed control strategies that allow the robot team to attempt to minimize the total time in which targets escape observation by some robot team member in the area of interest. This paper first formalizes the problem and discusses related work. The author then presents a distributed approximate approach to solving this problem that combines low-level multi-robot control with higher-level reasoning control based on the ALLIANCE formalism. The effectiveness of the approach is analyzed by comparing it to three other feasible algorithms for cooperative control, showing the superiority of the approach for a large class of problems

  11. Multi-robot motion control for cooperative observation

    Energy Technology Data Exchange (ETDEWEB)

    Parker, L.E. [Oak Ridge National Lab., TN (United States). Center for Engineering Systems Advanced Research

    1997-06-01

    An important issue that arises in the automation of many security, surveillance, and reconnaissance tasks is that of monitoring (or observing) the movements of targets navigating in a bounded area of interest. A key research issue in these problems is that of sensor placement--determining where sensors should be located to maintain the targets in view. In complex applications involving limited-range sensors, the use of multiple sensors dynamically moving over time is required. In this paper, the authors investigate the use of a cooperative team of autonomous sensor-based robots for the observation of multiple moving targets. They focus primarily on developing the distributed control strategies that allow the robot team to attempt to minimize the total time in which targets escape observation by some robot team member in the area of interest. This paper first formalizes the problem and discusses related work. The authors then present a distributed approximate approach to solving this problem that combines low-level multi-robot control with higher-level reasoning control based on the ALLIANCE formalism. They analyze the effectiveness of the approach by comparing it to 3 other feasible algorithms for cooperative control, showing the superiority of the approach for a large class of problems.

  12. Cooperative motion control for multi-target observation

    Energy Technology Data Exchange (ETDEWEB)

    Parker, L.E.

    1997-08-01

    An important issue that arises in the automation of many security, surveillance, and reconnaissance tasks is that of monitoring (or observing) the movements of targets navigating in a bounded area of interest. A key research issue in these problems is that of sensor placement--determining where sensors should be located to maintain the targets in view. In complex applications involving limited-range sensors, the use of multiple sensors dynamically moving over time is required. In this paper, the author investigates the use of a cooperative team of autonomous sensor-based robots for the observation of multiple moving targets. The focus is primarily on developing the distributed control strategies that allow the robot team to attempt to minimize the total time in which targets escape observation by some robot team member in the area of interest. This paper first formalizes the problem and discusses related work. The author then presents a distributed approximate approach to solving this problem that combines low-level multi-robot control with higher-level reasoning control based on the ALLIANCE formalism. The effectiveness of the approach is analyzed by comparing it to three other feasible algorithms for cooperative control, showing the superiority of the approach for a large class of problems.

  13. Remote control and motion coordination of mobile robots

    NARCIS (Netherlands)

    Alvarez Aguirre, A.

    2011-01-01

    As robots destined for personal and professional applications advance towards becoming part of our daily lives, the importance and complexity of the control algorithms which regulate them should not be underestimated. This thesis is related to two fields within robotics which are of major importance

  14. Brownian motion approximations for stock control and tankage assessment

    NARCIS (Netherlands)

    R.A.J.J. Nieboer; R. Dekker (Rommert)

    1995-01-01

    textabstractThis paper presents a model for refinery tankage assessment. Special characteristics covered are a hybrid demand process and a periodic-review target-stock policy for production control. The demand is assumed to be in two forms: as large parcels, collected at fixed intervals, and as many

  15. A Cable-Passive Damper System for Sway and Skew Motion Control of a Crane Spreader

    Directory of Open Access Journals (Sweden)

    La Duc Viet

    2015-01-01

    Full Text Available While the crane control problem is often approached by applying a certain active control command to some parts of the crane, this paper proposes a cable-passive damper system to reduce the vibration of a four-cable suspended crane spreader. The residual sway and skew motions of a crane spreader always produce the angle deflections between the crane cables and the crane spreader. The idea in this paper is to convert those deflections into energy dissipated by the viscous dampers, which connect the cables and the spreader. The proposed damper system is effective in reducing spreader sway and skew motions. Moreover, the optimal damping coefficient can be found analytically by minimizing the time integral of system energy. The numerical simulations show that the proposed passive system can assist the input shaping control of the trolley motion in reducing both sway and skew responses.

  16. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    Directory of Open Access Journals (Sweden)

    Seth B. Agyei

    2016-02-01

    Full Text Available During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this paper will describe behavioural and brain studies with young infants investigating the development of visual perception for prospective control. By means of the three visual motion paradigms of occlusion, looming, and optic flow, our research shows the importance of including behavioural data when studying the neural correlates of prospective control.

  17. Evaluation of the leap motion controller as a new contact-free pointing device.

    Science.gov (United States)

    Bachmann, Daniel; Weichert, Frank; Rinkenauer, Gerhard

    2014-12-24

    This paper presents a Fitts' law-based analysis of the user's performance in selection tasks with the Leap Motion Controller compared with a standard mouse device. The Leap Motion Controller (LMC) is a new contact-free input system for gesture-based human-computer interaction with declared sub-millimeter accuracy. Up to this point, there has hardly been any systematic evaluation of this new system available. With an error rate of 7.8% for the LMC and 2.8% for the mouse device, movement times twice as large as for a mouse device and high overall effort ratings, the Leap Motion Controller's performance as an input device for everyday generic computer pointing tasks is rather limited, at least with regard to the selection recognition provided by the LMC.

  18. The Application of Euler-Lagrange Method of Optimization for Electromechanical Motion Control

    Directory of Open Access Journals (Sweden)

    Cristian VASILACHE

    2000-12-01

    Full Text Available Industrial and non-industrial processes such as production plans, robots, pumps, compressors, home applications, transportation of people and goods etc., require some kinds of motion control. The main functions of electromechanical drives are to adjust these processes by controlling the torque, speed or position. The objective of this paper is to perform the control of motion while minimizing power losses, that is ∫Ri2dt, in process conversion of electrical energy to mechanical energy. The optimal control laws for our problem is find using the Euler - Lagrange principle. We consider three types of controlled drives: torque, speed and position. Each of them has different control laws. By implementation of these controls with Borland C++ and Matlab environment, substantial energy savings are obtained.

  19. The influence of motion control shoes on the running gait of mature and young females.

    Science.gov (United States)

    Lilley, Kim; Stiles, Vicky; Dixon, Sharon

    2013-03-01

    This study compared the running gait of mature and young females, and investigated the effect of a motion control shoe. First, it was hypothesised that in a neutral shoe, mature females would display significantly greater rearfoot eversion, knee internal rotation and external adductor moments when compared to a younger group. Secondly, the motion control shoe would reduce rearfoot eversion and knee internal rotation in both groups. Thirdly it was hypothesised that the motion control shoe would increase knee external adductor moment, through an increase in knee varus and moment arm. 15 mature (40-60 years) and 15 young (18-25 years) females performed 10 running trials at 3.5ms(-1)±5% over a force platform. Two shoes were tested, the Adidas Supernova Glide (neutral), and the Adidas Supernova Sequence (motion control). Ankle and knee joint dynamics were analysed for the right leg, and the mean of ten trials was calculated. Joint moments were calculated using inverse dynamics. In the neutral condition, mature females presented greater peak rearfoot eversion, knee internal rotation, and external adductor moments than young females (p<0.05). A motion control shoe significantly reduced peak rearfoot eversion and knee internal rotation among both groups (p<0.05). No between shoe differences in knee external adductor moment were observed. A motion control shoe is recommended to reduce risk of injury associated with rearfoot eversion and knee internal rotation in mature females. However since the knee external adductor moment is a variable commonly associated with medial knee loading it is suggested that alternative design features are required to influence this moment. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Controlling Motion at the Nanoscale: Rise of the Molecular Machines.

    Science.gov (United States)

    Abendroth, John M; Bushuyev, Oleksandr S; Weiss, Paul S; Barrett, Christopher J

    2015-08-25

    As our understanding and control of intra- and intermolecular interactions evolve, ever more complex molecular systems are synthesized and assembled that are capable of performing work or completing sophisticated tasks at the molecular scale. Commonly referred to as molecular machines, these dynamic systems comprise an astonishingly diverse class of motifs and are designed to respond to a plethora of actuation stimuli. In this Review, we outline the conditions that distinguish simple switches and rotors from machines and draw from a variety of fields to highlight some of the most exciting recent examples of opportunities for driven molecular mechanics. Emphasis is placed on the need for controllable and hierarchical assembly of these molecular components to display measurable effects at the micro-, meso-, and macroscales. As in Nature, this strategy will lead to dramatic amplification of the work performed via the collective action of many machines organized in linear chains, on functionalized surfaces, or in three-dimensional assemblies.

  1. Active Perturbation Rejection in Motion Control of Milling Machine Tools

    Directory of Open Access Journals (Sweden)

    Francisco Beltrán Carbajal

    2013-01-01

    Full Text Available En este artículo se aborda el problema de control robusto de los ejes de movimiento de máquinas- herramienta fresadoras sujetos a fuerzas de perturbación que se inducen durante el proceso de maquinado del metal. Se propone un esquema de control por retroalimentación de la salida de posición para el rechazo robusto de fuerzas de perturbación de fricción y de corte desconocidas, y para tareas de seguimiento robusto de trayectorias de movimiento planificadas para una máquina-herramienta fresadora de tres ejes. Se considera la fricción de Coulomb, el amortiguamiento viscoso y las fuerzas de corte como términos de una señal de entrada de perturbación variable en el tiempo desconocida, la cual afecta la dinámica de los ejes de movimiento de la máquina fresadora. En el diseño del control de movimiento, se modela la señal de perturbación mediante una familia de polinomios en el tiempo de Taylor de cuarto grado. Entonces, se diseña un observador de estado para estimar las señales de velocidad y perturbación que se requieren para la implementación del controlador de movimiento propuesto. Se incluye resultados en simulación para mostrar el desempeño robusto del esquema de control de movimiento propuesto y la estimación efectiva y rápida de las señales de perturbación y velocidad.

  2. Application of a Leap Motion Sensor for Improved Drone Control

    Science.gov (United States)

    2017-12-01

    gas , and mineral exploration,  Domestic surveillance,  Policing activities by law enforcement agencies,  Forest fire detection,  Precision...search and rescue missions,  Security of pipelines , power lines, coastline and borders monitoring for illegal immigration and imports,  Delivery...5.71 3.9 inches Motor Type Brush Motors Material Plastic, Metal Power Source Electric Remote Distance 10 - 12 meters Control Channels 3

  3. Motion modelling and control strategies of over-actuated vehicles

    OpenAIRE

    Edrén, Johannes

    2014-01-01

    With the growing concern for environmental change and uncertain oil resources, the development of new vehicle concepts will in many cases include full or partial electric propulsion. The introduction of more advanced powertrains enables vehicles that can be controlled with a variety of electric actuators, such as wheel hub motors and individual steering. With these actuators, the chassis can be enabled to adjust its properties depending on the driving situation. Manoeuvring of the vehicle, us...

  4. Combining spanwise morphing, inline motion and model based optimization for force magnitude and direction control

    Science.gov (United States)

    Scheller, Johannes; Braza, Marianna; Triantafyllou, Michael

    2016-11-01

    Bats and other animals rapidly change their wingspan in order to control the aerodynamic forces. A NACA0013 type airfoil with dynamically changing span is proposed as a simple model to experimentally study these biomimetic morphing wings. Combining this large-scale morphing with inline motion allows to control both force magnitude and direction. Force measurements are conducted in order to analyze the impact of the 4 degree of freedom flapping motion on the flow. A blade-element theory augmented unsteady aerodynamic model is then used to derive optimal flapping trajectories.

  5. Evaluation of the Leap Motion Controller as a New Contact-Free Pointing Device

    OpenAIRE

    Bachmann, Daniel; Weichert, Frank; Rinkenauer, Gerhard

    2014-01-01

    This paper presents a Fitts' law-based analysis of the user's performance in selection tasks with the Leap Motion Controller compared with a standard mouse device. The Leap Motion Controller (LMC) is a new contact-free input system for gesture-based human-computer interaction with declared sub-millimeter accuracy. Up to this point, there has hardly been any systematic evaluation of this new system available. With an error rate of 7.8 % for the LMC and 2.8% for the mouse device, movement times...

  6. Controlled motion in an elastic world. Research project: Manipulation strategies for massive space payloads

    Science.gov (United States)

    Book, Wayne J.

    1992-01-01

    The flexibility of the drives and structures of controlled motion systems are presented as an obstacle to be overcome in the design of high performance motion systems, particularly manipulator arms. The task and the measure of performance to be applied determine the technology appropriate to overcome this obstacle. Included in the technologies proposed are control algorithms (feedback and feed forward), passive damping enhancement, operational strategies, and structural design. Modeling of the distributed, nonlinear system is difficult, and alternative approaches are discussed. The author presents personal perspectives on the history, status, and future directions in this area.

  7. [Motion control of moving mirror based on fixed-mirror adjustment in FTIR spectrometer].

    Science.gov (United States)

    Li, Zhong-bing; Xu, Xian-ze; Le, Yi; Xu, Feng-qiu; Li, Jun-wei

    2012-08-01

    The performance of the uniform motion of the moving mirror, which is the only constant motion part in FTIR spectrometer, and the performance of the alignment of the fixed mirror play a key role in FTIR spectrometer, and affect the interference effect and the quality of the spectrogram and may restrict the precision and resolution of the instrument directly. The present article focuses on the research on the uniform motion of the moving mirror and the alignment of the fixed mirror. In order to improve the FTIR spectrometer, the maglev support system was designed for the moving mirror and the phase detection technology was adopted to adjust the tilt angle between the moving mirror and the fixed mirror. This paper also introduces an improved fuzzy PID control algorithm to get the accurate speed of the moving mirror and realize the control strategy from both hardware design and algorithm. The results show that the development of the moving mirror motion control system gets sufficient accuracy and real-time, which can ensure the uniform motion of the moving mirror and the alignment of the fixed mirror.

  8. Analysis of the Motion Control Methods for Stratospheric Balloon-Borne Gondola Platform

    Science.gov (United States)

    Wang, H. H.; Yuan, Z. H.; Wu, J.

    2006-10-01

    At present, gondola platform is one of the stratospheric balloon-borne platforms being in research focus at home and overseas. Comparing to other stratospheric balloon-borne platforms, such as airship platform, gondola platform has advantages of higher stability, rapid in motion regulation and lower energy cost but disadvantages of less supporting capacity and be incapable of fixation. While all platforms have the same goal of keeping them at accurate angle and right pose for the requirements of instruments and objects installed in the platforms, when platforms rotate round the ground level perpendicular. That is accomplishing motion control. But, platform control system has factors of low damper, excessive and uncertain disturbances by the reason of its being hung over balloon in the air, it is hard to achieve the desired control precision because platform is ease to deviate its benchmark motion. Thus, in the controlling procedure in order to get higher precision, it is crucial to perceive the platform's swing synchronously and rapidly, and restrain the influence of disturbances effectively, keep the platform's pose steadily. Furthermore, while the platform in the air regard control center in the ground as reference object, it is ultimate to select a appropriate reference frame and work out the coordinates and implement the adjustment by the PC104 controller. This paper introduces the methods of the motion control based on stratospheric balloon-borne gondola platform. Firstly, this paper compares the characteristic of the flywheel and CMG and specifies the key methods of obtaining two significant states which are 'orientation stability' state and 'orientation tracking' state for platform motion control procedure using CMG as the control actuator. These two states reduce the deviation amplitude of rotation and swing of gondola's motion relative to original motion due to stratospheric intense atmosphere disturbance. We define it as the first procedure. In next

  9. Analysis of the Motion Control Methods for Stratospheric Balloon-Borne Gondola Platform

    International Nuclear Information System (INIS)

    Wang, H H; Yuan, Z H; Wu, J

    2006-01-01

    At present, gondola platform is one of the stratospheric balloon-borne platforms being in research focus at home and overseas. Comparing to other stratospheric balloon-borne platforms, such as airship platform, gondola platform has advantages of higher stability, rapid in motion regulation and lower energy cost but disadvantages of less supporting capacity and be incapable of fixation. While all platforms have the same goal of keeping them at accurate angle and right pose for the requirements of instruments and objects installed in the platforms, when platforms rotate round the ground level perpendicular. That is accomplishing motion control. But, platform control system has factors of low damper, excessive and uncertain disturbances by the reason of its being hung over balloon in the air, it is hard to achieve the desired control precision because platform is ease to deviate its benchmark motion. Thus, in the controlling procedure in order to get higher precision, it is crucial to perceive the platform's swing synchronously and rapidly, and restrain the influence of disturbances effectively, keep the platform's pose steadily. Furthermore, while the platform in the air regard control center in the ground as reference object, it is ultimate to select a appropriate reference frame and work out the coordinates and implement the adjustment by the PC104 controller. This paper introduces the methods of the motion control based on stratospheric balloon-borne gondola platform. Firstly, this paper compares the characteristic of the flywheel and CMG and specifies the key methods of obtaining two significant states which are 'orientation stability' state and 'orientation tracking' state for platform motion control procedure using CMG as the control actuator. These two states reduce the deviation amplitude of rotation and swing of gondola's motion relative to original motion due to stratospheric intense atmosphere disturbance. We define it as the first procedure. In next

  10. Nonresonant Multiple-Pulse Control of Molecular Motions in Liquid

    Directory of Open Access Journals (Sweden)

    Nikiforov V.G.

    2015-01-01

    Full Text Available We propose the implementation of the multiple-pulse excitation for manipulation of the molecular contributions to the optically-heterodyne-detected optical-Kerr-effect. The key parameters controlling the specificity of the multiple-pulse excitation scenarios are the pulses durations, the delays between pulses, the relation between the pump pulses amplitudes and the pulses polarizations. We model the high-order optical responses and consider some principles of the scenarios construction. We show that it is possible to adjust the excitation scenario in such a way that the some responses can be removed from detected signal along with the enhancement of the interested response amplitude. The theoretical analysis and first experimental data reveal that the multiple-pulse excitation technique can be useful for the selective spectroscopy of the molecular vibrations and rotations in liquid.

  11. LAMI: A gesturally controlled three-dimensional stage Leap (Motion-based) Audio Mixing Interface

    OpenAIRE

    Wakefield, Jonathan P.; Dewey, Christopher; Gale, William

    2017-01-01

    Interface designers are increasingly exploring alternative approaches to user input/control. LAMI is a Leap (Motion-based) AMI which takes user’s hand gestures and maps these to a three-dimensional stage displayed on a computer monitor. Audio channels are visualised as spheres whose Y coordinate is spectral centroid and X and Z coordinates are controlled by hand position and represent pan and level respectively. Auxiliary send levels are controlled via wrist rotation and vertical hand positio...

  12. Convex optimisation approach to constrained fuel optimal control of spacecraft in close relative motion

    Science.gov (United States)

    Massioni, Paolo; Massari, Mauro

    2018-05-01

    This paper describes an interesting and powerful approach to the constrained fuel-optimal control of spacecraft in close relative motion. The proposed approach is well suited for problems under linear dynamic equations, therefore perfectly fitting to the case of spacecraft flying in close relative motion. If the solution of the optimisation is approximated as a polynomial with respect to the time variable, then the problem can be approached with a technique developed in the control engineering community, known as "Sum Of Squares" (SOS), and the constraints can be reduced to bounds on the polynomials. Such a technique allows rewriting polynomial bounding problems in the form of convex optimisation problems, at the cost of a certain amount of conservatism. The principles of the techniques are explained and some application related to spacecraft flying in close relative motion are shown.

  13. Evaluation of the Leap Motion Controller as a New Contact-Free Pointing Device

    Directory of Open Access Journals (Sweden)

    Daniel Bachmann

    2014-12-01

    Full Text Available This paper presents a Fitts’ law-based analysis of the user’s performance in selection tasks with the Leap Motion Controller compared with a standard mouse device. The Leap Motion Controller (LMC is a new contact-free input system for gesture-based human-computer interaction with declared sub-millimeter accuracy. Up to this point, there has hardly been any systematic evaluation of this new system available. With an error rate of 7.8% for the LMC and 2.8% for the mouse device, movement times twice as large as for a mouse device and high overall effort ratings, the Leap Motion Controller’s performance as an input device for everyday generic computer pointing tasks is rather limited, at least with regard to the selection recognition provided by the LMC.

  14. On transcending the impasse of respiratory motion correction applications in routine clinical imaging - a consideration of a fully automated data driven motion control framework

    International Nuclear Information System (INIS)

    Kesner, Adam L; Schleyer, Paul J; Büther, Florian; Walter, Martin A; Schäfers, Klaus P; Koo, Phillip J

    2014-01-01

    Positron emission tomography (PET) is increasingly used for the detection, characterization, and follow-up of tumors located in the thorax. However, patient respiratory motion presents a unique limitation that hinders the application of high-resolution PET technology for this type of imaging. Efforts to transcend this limitation have been underway for more than a decade, yet PET remains for practical considerations a modality vulnerable to motion-induced image degradation. Respiratory motion control is not employed in routine clinical operations. In this article, we take an opportunity to highlight some of the recent advancements in data-driven motion control strategies and how they may form an underpinning for what we are presenting as a fully automated data-driven motion control framework. This framework represents an alternative direction for future endeavors in motion control and can conceptually connect individual focused studies with a strategy for addressing big picture challenges and goals. The online version of this article (doi:10.1186/2197-7364-1-8) contains supplementary material, which is available to authorized users.

  15. Experimental investigation of shaping disturbance observer design for motion control of precision mechatronic stages with resonances

    Science.gov (United States)

    Yang, Jin; Hu, Chuxiong; Zhu, Yu; Wang, Ze; Zhang, Ming

    2017-08-01

    In this paper, shaping disturbance observer (SDOB) is investigated for precision mechatronic stages with middle-frequency zero/pole type resonance to achieve good motion control performance in practical manufacturing situations. Compared with traditional standard disturbance observer (DOB), in SDOB a pole-zero cancellation based shaping filter is cascaded to the mechatronic stage plant to meet the challenge of motion control performance deterioration caused by actual resonance. Noting that pole-zero cancellation is inevitably imperfect and the controller may even consequently become unstable in practice, frequency domain stability analysis is conducted to find out how each parameter of the shaping filter affects the control stability. Moreover, the robust design criterion of the shaping filter, and the design procedure of SDOB, are both proposed to guide the actual design and facilitate practical implementation. The SDOB with the proposed design criterion is applied to a linear motor driven stage and a voice motor driven stage, respectively. Experimental results consistently validate the effectiveness nature of the proposed SDOB scheme in practical mechatronics motion applications. The proposed SDOB design actually could be an effective unit in the controller design for motion stages of mechanical manufacture equipments.

  16. Coordinated Resolved Motion Control of Dual-Arm Manipulators with Closed Chain

    Directory of Open Access Journals (Sweden)

    Tianliang Liu

    2016-05-01

    Full Text Available When applied to some tasks, such as payload handling, assembling, repairing and so on, the two arms of a humanoid robot will form a closed kinematic chain. It makes the motion planning and control for dual-arm coordination very complex and difficult. In this paper, we present three types of resolved motion control methods for a humanoid robot during coordinated manipulation. They are, respectively, position-level, velocity-level and acceleration-level resolved motion control methods. The desired pose, velocity and acceleration of each end-effector are then resolved according to the desired motion of the payload and the constraints on the closed-chain system without consideration of the internal force. Corresponding to the three cases above, the joint variables of each arm are then calculated using the inverse kinematic equations, at position-level, velocity-level or acceleration-level. Finally, a dynamic modelling and simulation platform is established based on ADAMS and Matlab software. The proposed methods are verified by typical cases. The simulation results show that the proposed control strategy can realize the dual-arm coordinated operation and the internal force of the closed chain during the operation is controlled in a reasonable range at the same time.

  17. Motion control of multi-actuator hydraulic systems for mobile machineries: Recent advancements and future trends

    Science.gov (United States)

    Xu, Bing; Cheng, Min

    2018-06-01

    This paper presents a survey of recent advancements and upcoming trends in motion control technologies employed in designing multi-actuator hydraulic systems for mobile machineries. Hydraulic systems have been extensively used in mobile machineries due to their superior power density and robustness. However, motion control technologies of multi-actuator hydraulic systems have faced increasing challenges due to stringent emission regulations. In this study, an overview of the evolution of existing throttling control technologies is presented, including open-center and load sensing controls. Recent advancements in energy-saving hydraulic technologies, such as individual metering, displacement, and hybrid controls, are briefly summarized. The impact of energy-saving hydraulic technologies on dynamic performance and control solutions are also discussed. Then, the advanced operation methods of multi-actuator mobile machineries are reviewed, including coordinated and haptic controls. Finally, challenges and opportunities of advanced motion control technologies are presented by providing an overall consideration of energy efficiency, controllability, cost, reliability, and other aspects.

  18. A methodology for controlling motion and constraint forces in holonomically constrained systems

    International Nuclear Information System (INIS)

    Sapio, Vincent De; Srinivasa, Narayan

    2015-01-01

    Holonomic constraints are ubiquitous in multibody systems. We present an approach to effectively address the control of holonomically constrained systems using a novel decomposition of task, constraint, and posture space. In addition to providing a natural approach for motion control in the presence of constraints, this scheme also allows for concurrent specification of desired constraint forces, given sufficient actuation. It does this by exposing both motion coordinates and constraint forces within the control formalism, allowing for substantial flexibility in control synthesis. Implementations are presented based on a partitioning of the constraint forces into controlled and uncontrolled subsets, as well as a specification of implicit conditions on the constraint forces. A number of examples demonstrate the practical efficacy of the approach. Finally, a system-level methodology for constraint management during robot interactions with the environment is presented

  19. A methodology for controlling motion and constraint forces in holonomically constrained systems

    Energy Technology Data Exchange (ETDEWEB)

    Sapio, Vincent De, E-mail: vdesapio@hrl.com; Srinivasa, Narayan, E-mail: nsrinivasa@hrl.com [HRL Laboratories, LLC, Information and Systems Sciences Laboratory (United States)

    2015-02-15

    Holonomic constraints are ubiquitous in multibody systems. We present an approach to effectively address the control of holonomically constrained systems using a novel decomposition of task, constraint, and posture space. In addition to providing a natural approach for motion control in the presence of constraints, this scheme also allows for concurrent specification of desired constraint forces, given sufficient actuation. It does this by exposing both motion coordinates and constraint forces within the control formalism, allowing for substantial flexibility in control synthesis. Implementations are presented based on a partitioning of the constraint forces into controlled and uncontrolled subsets, as well as a specification of implicit conditions on the constraint forces. A number of examples demonstrate the practical efficacy of the approach. Finally, a system-level methodology for constraint management during robot interactions with the environment is presented.

  20. Motion Control of Four-Wheel Independently Actuated Electric Ground Vehicles considering Tire Force Saturations

    Directory of Open Access Journals (Sweden)

    Rongrong Wang

    2013-01-01

    Full Text Available A vehicle stability control approach for four-wheel independently actuated (FWIA electric vehicles is presented. The proposed control method consists of a higher-level controller and a lower-level controller. An adaptive control-based higher-level controller is designed to yield the vehicle virtual control efforts to track the desired vehicle motions due to the possible modeling inaccuracies and parametric uncertainties. The lower-level controller considering tire force saturation is given to allocate the required control efforts to the four in-wheel motors for providing the desired tire forces. An analytic method is given to distribute the high-level control efforts, without using the numerical-optimization-based control allocation algorithms. Simulations based on a high-fidelity, CarSim, and full-vehicle model show the effectiveness of the control approach.

  1. Interaction force and motion estimators facilitating impedance control of the upper limb rehabilitation robot.

    Science.gov (United States)

    Mancisidor, Aitziber; Zubizarreta, Asier; Cabanes, Itziar; Bengoa, Pablo; Jung, Je Hyung

    2017-07-01

    In order to enhance the performance of rehabilitation robots, it is imperative to know both force and motion caused by the interaction between user and robot. However, common direct measurement of both signals through force and motion sensors not only increases the complexity of the system but also impedes affordability of the system. As an alternative of the direct measurement, in this work, we present new force and motion estimators for the proper control of the upper-limb rehabilitation Universal Haptic Pantograph (UHP) robot. The estimators are based on the kinematic and dynamic model of the UHP and the use of signals measured by means of common low-cost sensors. In order to demonstrate the effectiveness of the estimators, several experimental tests were carried out. The force and impedance control of the UHP was implemented first by directly measuring the interaction force using accurate extra sensors and the robot performance was compared to the case where the proposed estimators replace the direct measured values. The experimental results reveal that the controller based on the estimators has similar performance to that using direct measurement (less than 1 N difference in root mean square error between two cases), indicating that the proposed force and motion estimators can facilitate implementation of interactive controller for the UHP in robotmediated rehabilitation trainings.

  2. Novel Motion Sensorless Control of Single Phase Brushless D.C. PM Motor Drive, with experiments

    DEFF Research Database (Denmark)

    Lepure, Liviu Ioan; Boldea, Ion; Andreescu, Gheorghe Daniel

    2010-01-01

    A motion sensorless control for single phase permanent magnet brushless d.c. (PM-BLDC) motor drives, based on flux integration and prior knowledge of the PM flux/position characteristic is proposed here and an adequate correction algorithm is adopted, in order to increase the robustness to noise...

  3. Vestibular Stimulation for ADHD: Randomized Controlled Trial of Comprehensive Motion Apparatus

    Science.gov (United States)

    Clark, David L.; Arnold, L. Eugene; Crowl, Lindsay; Bozzolo, Hernan; Peruggia, Mario; Ramadan, Yaser; Bornstein, Robert; Hollway, Jill A.; Thompson, Susan; Malone, Krista; Hall, Kristy L.; Shelton, Sara B.; Bozzolo, Dawn R.; Cook, Amy

    2008-01-01

    Objective: This research evaluates effects of vestibular stimulation by Comprehensive Motion Apparatus (CMA) in ADHD. Method: Children ages 6 to 12 (48 boys, 5 girls) with ADHD were randomized to thrice-weekly 30-min treatments for 12 weeks with CMA, stimulating otoliths and semicircular canals, or a single-blind control of equal duration and…

  4. Motion Controllers for Learners to Manipulate and Interact with 3D Objects for Mental Rotation Training

    Science.gov (United States)

    Yeh, Shih-Ching; Wang, Jin-Liang; Wang, Chin-Yeh; Lin, Po-Han; Chen, Gwo-Dong; Rizzo, Albert

    2014-01-01

    Mental rotation is an important spatial processing ability and an important element in intelligence tests. However, the majority of past attempts at training mental rotation have used paper-and-pencil tests or digital images. This study proposes an innovative mental rotation training approach using magnetic motion controllers to allow learners to…

  5. Extended state observer-based motion synchronisation control for hybrid actuation system of large civil aircraft

    Science.gov (United States)

    Wang, Xingjian; Shi, Cun; Wang, Shaoping

    2017-07-01

    Hybrid actuation system with dissimilar redundant actuators, which is composed of a hydraulic actuator (HA) and an electro-hydrostatic actuator (EHA), has been applied on modern civil aircraft to improve the reliability. However, the force fighting problem arises due to different dynamic performances between HA and EHA. This paper proposes an extended state observer (ESO)-based motion synchronisation control method. To cope with the problem of unavailability of the state signals, the well-designed ESO is utilised to observe the HA and EHA state variables which are unmeasured. In particular, the extended state of ESO can estimate the lumped effect of the unknown external disturbances acting on the control surface, the nonlinear dynamics, uncertainties, and the coupling term between HA and EHA. Based on the observed states of ESO, motion synchronisation controllers are presented to make HA and EHA to simultaneously track the desired motion trajectories, which are generated by a trajectory generator. Additionally, the unknown disturbances and the coupling terms can be compensated by using the extended state of the proposed ESO. Finally, comparative simulation results indicate that the proposed ESO-based motion synchronisation controller can achieve great force fighting reduction between HA and EHA.

  6. Pengenalan Isyarat Tangan Menggunakan Leap Motion Controller untuk Pertunjukan Boneka Tangan Virtual

    Directory of Open Access Journals (Sweden)

    Iskandar Dzulkarnain

    2017-01-01

    Full Text Available Leap Motion Controller memiliki keterbatasan dalam menangkap gerak isyarat tangan. Keterbatasan tersebut menyebabkan gerakan tangan model boneka virtual tidak seakurat gerakan tangan pelakon. Selain itu, konfigurasi bone model dimensi tiga untuk Leap Motion Controller berbeda dengan konfigurasi bone dimensi tiga pada umumnya. Oleh karena itu, dilakukan pengenalan isyarat tangan menggunakan Leap Motion Controller untuk pertunjukan boneka tangan virtual. Pengenalan isyarat tangan tersebut dilakukan dengan memetakan hasil penjejakan tangan dari Leap Motion Controller ke dalam model prefab tangan Leap SDK. Setelah berhasil dipetakan, konfigurasi bone dari model prefab tangan Leap SDK diadaptasi ke dalam model boneka tangan virtual. Adaptasi tersebut dilakukan dengan mengatur posisi dan orientasi bone pada model dimensi tiga boneka tangan. Setelah posisi dan orientasi bone yang sesuai ditemukan, model dimensi tiga boneka tangan diuji menirukan gerakan boneka tangan asli. Pengujian boneka tangan virtual pada sembarang orang dilakukan untuk mengetahui tingkat kesinkronan gerak mulut atas dan mulut bawah boneka tangan virtual. Dari pengujian sembarang orang, didapatkan hasil 50% setuju dan 5,6% sangat setuju gerak mulut atas sinkron dengan gerak tangan. Sedangkan untuk gerak mulut bawah sinkron dengan gerak tangan didapatkan 16,7% setuju dan 11,1% sangat setuju.

  7. Mechatronic System Design and Intelligent Motion Control of Hydraulic Robots and Machines

    DEFF Research Database (Denmark)

    Conrad, Finn; Sørensen, Torben

    2003-01-01

    The paper presents an approach and concept to mechatronic system design and intelligent motion control. The Information Technology (IT) offers software and hardware for improvement of R&D Mechatronic Teams to create products and solutions for industrial applications. The latest progress in IT makes...... integration of an overall design and manufacturing IT- concept feasible and commercially attractive. An IT-tool concept for modelling, simulation and design of mechatronic products and systems is proposed in this paper. It built on results from a Danish mechatronic research program on intelligent motion...

  8. Voltage Sags Ride-Through of Motion Sensorless Controlled PMSG for Wind Turbines

    DEFF Research Database (Denmark)

    Fatu, Marius; Lascu, Cristian; Andreescu, Gheorghe-Daniel

    2007-01-01

    This paper describes a variable-speed motion-sensorless permanent magnet synchronous generator (PMSG) control system for wind energy generation. The proposed system contains a PMSG connected to the grid by a back-to-back PWM inverter with bidirectional power flow, a line filter, and a transformer....... The control system employs PI current controllers with crosscoupling decoupling for both inverters, an active power controller, and a DC link voltage controller. The PMSG rotor speed without using emf integration, and the line voltage frequency are estimated by two PLL based observers. A Dmodule filter...

  9. Mitigation of ground motion effects in linear accelerators via feed-forward control

    Directory of Open Access Journals (Sweden)

    J. Pfingstner

    2014-12-01

    Full Text Available Ground motion is a severe problem for many particle accelerators, since it excites beam oscillations, which decrease the beam quality and create beam-beam offset (at colliders. Orbit feedback systems can only compensate ground motion effects at frequencies significantly smaller than the beam repetition rate. In linear colliders, where the repetition rate is low, additional counter measures have to be put in place. For this reason, a ground motion mitigation method based on feed-forward control is presented in this paper. It has several advantages compared to other techniques (stabilization systems and intratrain feedback systems such as cost reduction and potential performance improvement. An analytical model is presented that allows the derivation of hardware specification and performance estimates for a specific accelerator and ground motion model. At the Accelerator Test Facility (ATF2, ground motion sensors have been installed to verify the feasibility of important parts of the mitigation strategy. In experimental studies, it has been shown that beam excitations due to ground motion can be predicted from ground motion measurements on a pulse-to-pulse basis. Correlations of up to 80% between the estimated and measured orbit jitter have been observed. Additionally, an orbit jitter source was identified and has been removed, which halved the orbit jitter power at ATF2 and shows that the feed-forward scheme is also very useful for the detection of installation issues. We believe that the presented mitigation method has the potential to reduce costs and improve the performance of linear colliders and potentially other linear accelerators.

  10. Possible influences on color constancy by motion of color targets and by attention-controlled gaze.

    Science.gov (United States)

    Wan, Lifang; Shinomori, Keizo

    2018-04-01

    We investigated the influence of motion on color constancy using a chromatic stimulus presented in various conditions (static, motion, and rotation). Attention to the stimulus and background was also controlled in different gaze modes, constant fixation of the stimulus, and random viewing of the stimulus. Color constancy was examined in six young observers using a haploscopic view of a computer monitor. The target and background were illuminated in simulation by red, green, blue, and yellow, shifted from daylight (D65) by specific color differences along L - M or S - (L + M) axes on the equiluminance plane. The standard pattern (under D65) and test pattern (under the color illuminant) of a 5-deg square were presented side by side, consisting of 1.2-deg square targets with one of 12 colors at each center, surrounded by 230 background ellipses consisting of eight other colors. The central color targets in both patterns flipped between top and bottom locations at the rate of 3 deg/s in the motion condition. The results indicated an average reduction of color constancy over the 12 test colors by motion. The random viewing parameter indicated better color constancy by more attention to the background, although the difference was not significant. Color constancy of the four color illuminations was better to worse in green, red, yellow, and blue, respectively. The reduction of color constancy by motion could be explained by less contribution of the illumination estimation effect on color constancy. In the motion with constant fixation condition, the retina strongly adapted to the mean chromaticity of the background. However, motion resulted in less attention to the color of the background, causing a weaker effect of the illumination estimation. Conversely, in the static state with a random viewing condition, more attention to the background colors caused a stronger illumination estimation effect, and color constancy was improved overall.

  11. Research on Coordinated Robotic Motion Control Based on Fuzzy Decoupling Method in Fluidic Environments

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-01-01

    Full Text Available The underwater recovery of autonomous underwater vehicles (AUV is a process of 6-DOF motion control, which is related to characteristics with strong nonlinearity and coupling. In the recovery mission, the vehicle requires high level control accuracy. Considering an AUV called BSAV, this paper established a kinetic model to describe the motion of AUV in the horizontal plane, which consisted of nonlinear equations. On the basis of this model, the main coupling variables were analyzed during recovery. Aiming at the strong coupling problem between the heading control and sway motion, we designed a decoupling compensator based on the fuzzy theory and the decoupling theory. We analyzed to the rules of fuzzy compensation, the input and output membership functions of fuzzy compensator, through compose operation and clear operation of fuzzy reasoning, and obtained decoupling compensation quantity. Simulation results show that the fuzzy decoupling controller effectively reduces the overshoot of the system, and improves the control precision. Through the water tank experiments and analysis of experimental data, the effectiveness and feasibility of AUV recovery movement coordinated control based on fuzzy decoupling method are validated successful, and show that the fuzzy decoupling control method has a high practical value in the recovery mission.

  12. Estafette of drift resonances, stochasticity and control of particle motion in a toroidal magnetic trap

    International Nuclear Information System (INIS)

    Shishkin, Alexander A.

    2001-02-01

    A new method of particle motion control in toroidal magnetic traps with rotational transform using the estafette of drift resonances and stochasticity of particle trajectories is proposed. The use of the word estafette' here means that the particle passes through a set of resonances in consecutive order from one to another during its motion. The overlapping of adjacent resonances can be moved radially from the center to the edge of the plasma by switching on the corresponding perturbations in accordance with a particular rule in time. In this way particles (e.g. cold alpha-particle) can be removed from the center of the confinement volume to the plasma periphery. For the analytical treatment of the stochastic behaviour of particle motion the stochastic diffusion coefficients D r, r, D r,θ , D θ,θ are introduced. The new approach is demonstrated by numerical computations of the test helium particle trajectories in the toroidal trap Large Helical Device. (author)

  13. Temperature-Responsive Anisotropic Slippery Surface for Smart Control of the Droplet Motion.

    Science.gov (United States)

    Wang, By Lili; Heng, Liping; Jiang, Lei

    2018-02-28

    Development of stimulus-responsive anisotropic slippery surfaces is important because of the high demand for such materials in the field of liquid directional-driven systems. However, current studies in the field of slippery surfaces are mainly conducted to prepare isotropic slippery surfaces. Although we have developed electric-responsive anisotropic slippery surfaces that enable smart control of the droplet motion, there remain challenges for designing temperature-responsive anisotropic slippery surfaces to control the liquid droplet motion on the surface and in the tube. In this work, temperature-responsive anisotropic slippery surfaces have been prepared by using paraffin, a thermo-responsive phase-transition material, as a lubricating fluid and directional porous polystyrene (PS) films as the substrate. The smart regulation of the droplet motion of several liquids on this surface was accomplished by tuning the substrate temperature. The uniqueness of this surface lies in the use of an anisotropic structure and temperature-responsive lubricating fluids to achieve temperature-driven smart control of the anisotropic motion of the droplets. Furthermore, this surface was used to design temperature-driven anisotropic microreactors and to manipulate liquid transfer in tubes. This work advances the understanding of the principles underlying anisotropic slippery surfaces and provides a promising material for applications in the biochip and microreactor system.

  14. ANALYSIS OF PERTURBED MOTION STABILITY OF WHEELER VEHICLES BRAKES CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Verbytskiyi

    2011-01-01

    Full Text Available The analysis of the perturbed motion stability of the brake automatic control system on the basis of Lyapunov’s second method is carried out. Using transformations of Lurie there has been ob-tained the canonical form of the system of equations of automatic control. It allowed determining the necessary and sufficient conditions of the asymptotic stability of the system irrespective of its initial condition and a definite choice of the admissible characteristic of the regulator.

  15. The Motion Path Study of Measuring Robot Based on Variable Universe Fuzzy Control

    Directory of Open Access Journals (Sweden)

    Ma Guoqing

    2017-01-01

    Full Text Available For the problem of measuring robot requires a higher positioning, firstly learning about the error overview of the system, analysised the influence of attitude, speed and other factors on systematic errors. Then collected and analyzed the systematic error curve in the track to complete the planning process. The last adding fuzzy control in both cases, by comparing with the original system, can found that the method based on fuzzy control system can significantly reduce the error during the motion.

  16. Real-time high-speed motion blur compensation system based on back-and-forth motion control of galvanometer mirror.

    Science.gov (United States)

    Hayakawa, Tomohiko; Watanabe, Takanoshin; Ishikawa, Masatoshi

    2015-12-14

    We developed a novel real-time motion blur compensation system for the blur caused by high-speed one-dimensional motion between a camera and a target. The system consists of a galvanometer mirror and a high-speed color camera, without the need for any additional sensors. We controlled the galvanometer mirror with continuous back-and-forth oscillating motion synchronized to a high-speed camera. The angular speed of the mirror is given in real time within 10 ms based on the concept of background tracking and rapid raw Bayer block matching. Experiments demonstrated that our system captures motion-invariant images of objects moving at speeds up to 30 km/h.

  17. Motion Perception and Manual Control Performance During Passive Tilt and Translation Following Space Flight

    Science.gov (United States)

    Clement, Gilles; Wood, Scott J.

    2010-01-01

    This joint ESA-NASA study is examining changes in motion perception following Space Shuttle flights and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. METHODS. Data has been collected on 5 astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation (216 deg/s) combined with body translation (12-22 cm, peak-to-peak) is utilized to elicit roll-tilt perception (equivalent to 20 deg, peak-to-peak). A forward-backward moving sled (24-390 cm, peak-to-peak) with or without chair tilting in pitch is utilized to elicit pitch tilt perception (equivalent to 20 deg, peak-to-peak). These combinations are elicited at 0.15, 0.3, and 0.6 Hz for evaluating the effect of motion frequency on tilt-translation ambiguity. In both devices, a closed-loop nulling task is also performed during pseudorandom motion with and without vibrotactile feedback of tilt. All tests are performed in complete darkness. PRELIMINARY RESULTS. Data collection is currently ongoing. Results to date suggest there is a trend for translation motion perception to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. DISCUSSION. The results of this study indicate that post-flight recovery of motion perception and manual control performance is complete within 8 days following short-duration space missions. Vibrotactile feedback of tilt improves manual control performance both before and after flight.

  18. Motion control in double-walled carbon nanotube systems using a Stone-Thrower-Wales defect cluster

    International Nuclear Information System (INIS)

    Liu Ping; Zhang Yongwei

    2010-01-01

    The ability to control the motion of a single molecule will have an important impact in nano-mechanical systems. Multi-walled carbon nanotube systems, which have extremely low intertube friction and strong motion confinement, can form the basis for mechanically based motion control. We devise two molecular motion control units based on double-walled carbon nanotubes embedded with a Stone-Thrower-Wales defect cluster, and perform molecular dynamics simulations to determine the characteristics of these two control units. We show that one of the molecular control units is able to perform a logic operation on one logic input and produce three logic outputs, while the other is able to produce two logic outputs. Potential applications of the motion control units include molecular switches, shuttles and mechanically based logic devices.

  19. Pitching motion control of a butterfly-like 3D flapping wing-body model

    Science.gov (United States)

    Suzuki, Kosuke; Minami, Keisuke; Inamuro, Takaji

    2014-11-01

    Free flights and a pitching motion control of a butterfly-like flapping wing-body model are numerically investigated by using an immersed boundary-lattice Boltzmann method. The model flaps downward for generating the lift force and backward for generating the thrust force. Although the model can go upward against the gravity by the generated lift force, the model generates the nose-up torque, consequently gets off-balance. In this study, we discuss a way to control the pitching motion by flexing the body of the wing-body model like an actual butterfly. The body of the model is composed of two straight rigid rod connected by a rotary actuator. It is found that the pitching angle is suppressed in the range of +/-5° by using the proportional-plus-integral-plus-derivative (PID) control for the input torque of the rotary actuator.

  20. The motion and control of a complex three-body space tethered system

    Science.gov (United States)

    Shi, Gefei; Zhu, Zhanxia; Chen, Shiyu; Yuan, Jianping; Tang, Biwei

    2017-11-01

    This paper is mainly devoted to investigating the dynamics and stability control of a three body-tethered satellite system which contains a main satellite and two subsatellites connected by two straight, massless and inextensible tethers. Firstly, a detailed mathematical model is established in the central gravitational field. Then, the dynamic characteristics of the established system are investigated and analyzed. Based on the dynamic analysis, a novel sliding mode prediction model (SMPM) control strategy is proposed to suppress the motion of the built tethered system. The numerical results show that the proposed underactuated control law is highly effective in suppressing the attitude/libration motion of the underactuated three-body tethered system. Furthermore, cases of different target angles are also examined and analyzed. The simulation results reveal that even if the final equilibrium states differ from different selections of the target angles, the whole system can still be maintained in acceptable areas.

  1. Imparting Motion to a Test Object Such as a Motor Vehicle in a Controlled Fashion

    Science.gov (United States)

    Southward, Stephen C. (Inventor); Reubush, Chandler (Inventor); Pittman, Bryan (Inventor); Roehrig, Kurt (Inventor); Gerard, Doug (Inventor)

    2014-01-01

    An apparatus imparts motion to a test object such as a motor vehicle in a controlled fashion. A base has mounted on it a linear electromagnetic motor having a first end and a second end, the first end being connected to the base. A pneumatic cylinder and piston combination have a first end and a second end, the first end connected to the base so that the pneumatic cylinder and piston combination is generally parallel with the linear electromagnetic motor. The second ends of the linear electromagnetic motor and pneumatic cylinder and piston combination being commonly linked to a mount for the test object. A control system for the linear electromagnetic motor and pneumatic cylinder and piston combination drives the pneumatic cylinder and piston combination to support a substantial static load of the test object and the linear electromagnetic motor to impart controlled motion to the test object.

  2. Modeling, system identification, and control for slosh-free motion of an open container of liquid

    International Nuclear Information System (INIS)

    Feddema, J.; Baty, R.; Dykhuizen, R.; Dohrmann, C.; Parker, G.; Robinett, R.; Romero, V.; Schmitt, D.

    1996-04-01

    This report discusses work performed under a Cooperative Research And Development Agreement (CRADA) with Corning, Inc., to analyze and test various techniques for controlling the motion of a high speed robotic arm carrying an open container of viscous liquid, in this case, molten glass. A computer model was generated to estimate the modes of oscillation of the liquid based on the shape of the container and the viscosity of the liquid. This fluid model was experimentally verified and tuned based on experimental data from a capacitive sensor on the side of the container. A model of the robot dynamics was also developed and verified through experimental tests on a Fanuc S-800 robot arm. These two models were used to estimate the overall modes of oscillation of an open container of liquid being carried by a robot arm. Using the estimated modes, inverse dynamic control techniques were used to determine a motion profile which would eliminate waves on the liquid's surface. Experimental tests showed that residual surface waves in an open container of water at the end of motion were reduced by over 95% and that in-motion surface waves were reduced by over 75%

  3. Shallow and deep controls on lava lake surface motion at Kīlauea Volcano

    Science.gov (United States)

    Patrick, Matthew R.; Orr, Tim R.; Swanson, Don; Lev, Einat

    2016-01-01

    Lava lakes provide a rare window into magmatic behavior, and lake surface motion has been used to infer deeper properties of the magmatic system. At Halema'uma'u Crater, at the summit of Kīlauea Volcano, multidisciplinary observations for the past several years indicate that lava lake surface motion can be broadly divided into two regimes: 1) stable and 2) unstable. Stable behavior is driven by lava upwelling from deeper in the lake (presumably directly from the conduit) and is an intrinsic process that drives lava lake surface motion most of the time. This stable behavior can be interrupted by periods of unstable flow (often reversals) driven by spattering – a shallowly-rooted process often extrinsically triggered by small rockfalls from the crater wall. The bursting bubbles at spatter sources create void spaces and a localized surface depression which draws and consumes surrounding surface crust. Spattering is therefore a location of lava downwelling, not upwelling. Stable (i.e. deep, upwelling-driven) and unstable (i.e. shallow, spattering-driven) behavior often alternate through time, have characteristic surface velocities, flow directions and surface temperature regimes, and also correspond to changes in spattering intensity, outgassing rates, lava level and seismic tremor. These results highlight that several processes, originating at different depths, can control the motion of the lava lake surface, and long-term interdisciplinary monitoring is required to separate these influences. These observations indicate that lake surface motion is not always a reliable proxy for deeper lake or magmatic processes. From these observations, we suggest that shallow outgassing (spattering), not lake convection, drives the variations in lake motion reported at Erta 'Ale lava lake.

  4. Integrated direct/indirect adaptive robust motion trajectory tracking control of pneumatic cylinders

    Science.gov (United States)

    Meng, Deyuan; Tao, Guoliang; Zhu, Xiaocong

    2013-09-01

    This paper studies the precision motion trajectory tracking control of a pneumatic cylinder driven by a proportional-directional control valve. An integrated direct/indirect adaptive robust controller is proposed. The controller employs a physical model based indirect-type parameter estimation to obtain reliable estimates of unknown model parameters, and utilises a robust control method with dynamic compensation type fast adaptation to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. Due to the use of projection mapping, the robust control law and the parameter adaption algorithm can be designed separately. Since the system model uncertainties are unmatched, the recursive backstepping technology is adopted to design the robust control law. Extensive comparative experimental results are presented to illustrate the effectiveness of the proposed controller and its performance robustness to parameter variations and sudden disturbances.

  5. Virtual reality-based assessment of basic laparoscopic skills using the Leap Motion controller.

    Science.gov (United States)

    Lahanas, Vasileios; Loukas, Constantinos; Georgiou, Konstantinos; Lababidi, Hani; Al-Jaroudi, Dania

    2017-12-01

    The majority of the current surgical simulators employ specialized sensory equipment for instrument tracking. The Leap Motion controller is a new device able to track linear objects with sub-millimeter accuracy. The aim of this study was to investigate the potential of a virtual reality (VR) simulator for assessment of basic laparoscopic skills, based on the low-cost Leap Motion controller. A simple interface was constructed to simulate the insertion point of the instruments into the abdominal cavity. The controller provided information about the position and orientation of the instruments. Custom tools were constructed to simulate the laparoscopic setup. Three basic VR tasks were developed: camera navigation (CN), instrument navigation (IN), and bimanual operation (BO). The experiments were carried out in two simulation centers: MPLSC (Athens, Greece) and CRESENT (Riyadh, Kingdom of Saudi Arabia). Two groups of surgeons (28 experts and 21 novices) participated in the study by performing the VR tasks. Skills assessment metrics included time, pathlength, and two task-specific errors. The face validity of the training scenarios was also investigated via a questionnaire completed by the participants. Expert surgeons significantly outperformed novices in all assessment metrics for IN and BO (p assessment of basic laparoscopic skills. The proposed system allowed the evaluation of dexterity of the hand movements. Future work will involve comparison studies with validated simulators and development of advanced training scenarios on current Leap Motion controller.

  6. Motion Control Design for an Omnidirectional Mobile Robot Subject to Velocity Constraints

    Directory of Open Access Journals (Sweden)

    Ollin Peñaloza-Mejía

    2015-01-01

    Full Text Available A solution to achieve global asymptotic tracking with bounded velocities in an omnidirectional mobile robot is proposed in this paper. It is motivated by the need of having a useful in-practice motion control scheme, which takes into account the physical limits of the velocities. To this end, a passive nonlinear controller is designed and combined with a tracking controller in a negative feedback connection structure. By using Lyapunov theory and passivity tools, global asymptotic tracking with desired bounded velocities is proved. Simulations and experimental results are provided to show the effectiveness of the proposal.

  7. Control of nonholonomic systems from sub-Riemannian geometry to motion planning

    CERN Document Server

    Jean, Frédéric

    2014-01-01

    Nonholonomic systems are control systems which depend linearly on the control. Their underlying geometry is the sub-Riemannian geometry, which plays for these systems the same role as Euclidean geometry does for linear systems. In particular the usual notions of approximations at the first order, that are essential for control purposes, have to be defined in terms of this geometry. The aim of these notes is to present these notions of approximation and their application to the motion planning problem for nonholonomic systems.

  8. Development of virtual reality exercise of hand motion assist robot for rehabilitation therapy by patient self-motion control.

    Science.gov (United States)

    Ueki, Satoshi; Nishimoto, Yutaka; Abe, Motoyuki; Kawasaki, Haruhisa; Ito, Satoshi; Ishigure, Yasuhiko; Mizumoto, Jun; Ojika, Takeo

    2008-01-01

    This paper presents a virtual reality-enhanced hand rehabilitation support system with a symmetric master-slave motion assistant for independent rehabilitation therapies. Our aim is to provide fine motion exercise for a hand and fingers, which allows the impaired hand of a patient to be driven by his or her healthy hand on the opposite side. Since most disabilities caused by cerebral vascular accidents or bone fractures are hemiplegic, we adopted a symmetric master-slave motion assistant system in which the impaired hand is driven by the healthy hand on the opposite side. A VR environment displaying an effective exercise was created in consideration of system's characteristic. To verify the effectiveness of this system, a clinical test was executed by applying to six patients.

  9. Autonomous tracked robots in planar off-road conditions modelling, localization, and motion control

    CERN Document Server

    González, Ramón; Guzmán, José Luis

    2014-01-01

    This monograph is framed within the context of off-road mobile robotics. In particular, it discusses issues related to modelling, localization, and motion control of tracked mobile robots working in planar slippery conditions. Tracked locomotion constitutes a well-known solution for mobile platforms operating over diverse challenging terrains, for that reason, tracked robotics constitutes an important research field with many applications (e.g. agriculture, mining, search and rescue operations, military activities). The specific topics of this monograph are: historical perspective of tracked vehicles and tracked robots; trajectory-tracking model taking into account slip effect; visual-odometry-based localization strategies; and advanced slip-compensation motion controllers ensuring efficient real-time execution. Physical experiments with a real tracked robot are presented showing the better performance of the suggested novel approaches to known techniques.   Keywords: longitudinal slip, visual odometry, slip...

  10. CDIO-Concept for Enginering Education in Fluid Power, Motion Control and Mechatronic Design

    DEFF Research Database (Denmark)

    Conrad, Finn; Andersen, Torben O.; Hansen, Michael Rygaard

    2006-01-01

    of mechatronics solutions with fluid power actuators for motion control of machines and robots. The idea of CDIO-Concept is to take care of that the students are learning by doing and learning while doing when the students are active to generate new products and solutions by going through the phases from......The paper presents significant Danish experiment results of a developed CDIO-Concept and approach for active and integrated learning in today’s engineering education of MSc Degree students, and research results from using IT-Tools for CAE/CAD and dynamic modelling, simulation, analysis, and design...... to Conceive, Design, Implement and Operate related to en product design by them self in competition with others. The idea is based on the Danish implementation of a CDIO-Concept. A curriculum at Aalborg University, and Technical University of Denmark, offers courses for Motion Control, Fluid Power within...

  11. Adaptive Robust Motion Control of Direct-Drive DC Motors with Continuous Friction Compensation

    Directory of Open Access Journals (Sweden)

    Jianyong Yao

    2013-01-01

    Full Text Available Uncertainties including the structured and unstructured, especially the nonlinear frictions, always exist in physical servo systems and degrade their tracking accuracy. In this paper, a practical method named adaptive robust controller (ARC is synthesized with a continuous differentiable friction model for high accuracy motion control of a direct-drive dc motor, which results in a continuous control input and thus is more suitable for application. To further reduce the noise sensitivity and improve the tracking accuracy, a desired compensation version of the proposed adaptive robust controller is also developed and its stability is guaranteed by a proper robust law. The proposed controllers not only account for the structured uncertainties (e.g., parametric uncertainties but also for the unstructured uncertainties (e.g., unconsidered nonlinear frictions. Furthermore, the controllers theoretically guarantee a prescribed output tracking transient performance and final tracking accuracy in both structured and unstructured uncertainties while achieving asymptotic output tracking in the absence of unstructured uncertainties, which is very important for high accuracy control of motion systems. Extensive comparative experimental results are obtained to verify the high-performance nature of the proposed control strategies.

  12. An EMG Interface for the Control of Motion and Compliance of a Supernumerary Robotic Finger

    Science.gov (United States)

    Hussain, Irfan; Spagnoletti, Giovanni; Salvietti, Gionata; Prattichizzo, Domenico

    2016-01-01

    In this paper, we propose a novel electromyographic (EMG) control interface to control motion and joints compliance of a supernumerary robotic finger. The supernumerary robotic fingers are a recently introduced class of wearable robotics that provides users additional robotic limbs in order to compensate or augment the existing abilities of natural limbs without substituting them. Since supernumerary robotic fingers are supposed to closely interact and perform actions in synergy with the human limbs, the control principles of extra finger should have similar behavior as human’s ones including the ability of regulating the compliance. So that, it is important to propose a control interface and to consider the actuators and sensing capabilities of the robotic extra finger compatible to implement stiffness regulation control techniques. We propose EMG interface and a control approach to regulate the compliance of the device through servo actuators. In particular, we use a commercial EMG armband for gesture recognition to be associated with the motion control of the robotic device and surface one channel EMG electrodes interface to regulate the compliance of the robotic device. We also present an updated version of a robotic extra finger where the adduction/abduction motion is realized through ball bearing and spur gears mechanism. We have validated the proposed interface with two sets of experiments related to compensation and augmentation. In the first set of experiments, different bimanual tasks have been performed with the help of the robotic device and simulating a paretic hand since this novel wearable system can be used to compensate the missing grasping abilities in chronic stroke patients. In the second set, the robotic extra finger is used to enlarge the workspace and manipulation capability of healthy hands. In both sets, the same EMG control interface has been used. The obtained results demonstrate that the proposed control interface is intuitive and can

  13. Design and motion control of bioinspired humanoid robot head from servo motors toward artificial muscles

    Science.gov (United States)

    Almubarak, Yara; Tadesse, Yonas

    2017-04-01

    The potential applications of humanoid robots in social environments, motivates researchers to design, and control biomimetic humanoid robots. Generally, people are more interested to interact with robots that have similar attributes and movements to humans. The head is one of most important part of any social robot. Currently, most humanoid heads use electrical motors, pneumatic actuators, and shape memory alloy (SMA) actuators for actuation. Electrical and pneumatic actuators take most of the space and would cause unsmooth motions. SMAs are expensive to use in humanoids. Recently, in many robotic projects, Twisted and Coiled Polymer (TCP) artificial muscles are used as linear actuators which take up little space compared to the motors. In this paper, we will demonstrate the designing process and motion control of a robotic head with TCP muscles. Servo motors and artificial muscles are used for actuating the head motion, which have been controlled by a cost efficient ARM Cortex-M7 based development board. A complete comparison between the two actuators is presented.

  14. Hybrid task priority-based motion control of a redundant free-floating space robot

    Directory of Open Access Journals (Sweden)

    Cheng ZHOU

    2017-12-01

    Full Text Available This paper presents a novel hybrid task priority-based motion planning algorithm of a space robot. The satellite attitude control task is defined as the primary task, while the least-squares-based non-strict task priority solution of the end-effector plus the multi-constraint task is viewed as the secondary task. Furthermore, a null-space task compensation strategy in the joint space is proposed to derive the combination of non-strict and strict task-priority motion planning, and this novel combination is termed hybrid task priority control. Thus, the secondary task is implemented in the primary task’s null-space. Besides, the transition of the state of multiple constraints between activeness and inactiveness will only influence the end-effector task without any effect on the primary task. A set of numerical experiments made in a real-time simulation system under Linux/RTAI shows the validity and feasibility of the proposed methodology. Keywords: Base attitude control, Hybrid task-priority, Motion planning, Multiple constraints, Redundant space robot

  15. Feedback attitude sliding mode regulation control of spacecraft using arm motion

    Science.gov (United States)

    Shi, Ye; Liang, Bin; Xu, Dong; Wang, Xueqian; Xu, Wenfu

    2013-09-01

    The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields. Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance, so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints. Thus, sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process. Due to the switching effects of the variable structure controller, once the tracking error reaches the designed hyper-plane, it will be restricted to this plane permanently even with the existence of external disturbances. Thus, precise attitude regulation can be achieved. Furthermore, taking the non-zero initial tracking errors and chattering phenomenon into consideration, saturation functions are used to replace sign functions to smooth the control torques. The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller. Mathematical models of free-floating space manipulator are established and simulations are conducted in the end. The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm, the steady state error is 0.000 2 rad. In addition, the joint tracking trajectory is smooth, the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input. The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion, and improves the precision of the spacecraft attitude regulation.

  16. Shoulder Dynamic Control Ratio and Rotation Range of Motion in Female Junior Elite Handball Players and Controls.

    Science.gov (United States)

    van Cingel, Robert; Habets, Bas; Willemsen, Linn; Staal, Bart

    2018-03-01

    To compare glenohumeral range of motion and shoulder rotator muscle strength in healthy female junior elite handball players and controls. Cross-sectional case-control study. Sports medical center. Forty elite female handball players and 30 controls active in nonoverhead sports participated in this study. Passive external rotator (ER), internal rotator (IR), and total range of motion (TROM) of the dominant and nondominant arm were examined with a goniometer. An isokinetic dynamometer was used to evaluate concentric and eccentric rotator muscle strength at 60 and 120 degrees/s with dynamic control ratio (DCR = ERecc:IRcon) as the main outcome parameter. Except for the ER range of motion in the nondominant arm, no significant differences were found between groups for IR, ER of the dominant arm, and the TROM. Within the handball group, the side-to-side difference for IR of the dominant arm was -1.4 degrees. The ER and the TROM of the dominant arm were significantly larger, 6.3 and 4.9 degrees, respectively. For both groups, the DCR values were above 1 and no significant differences were found between the dominant and nondominant arm. The DCR values in the handball group were significantly lower than in the control group. Based on the adopted definitions for muscle imbalance, glenohumeral internal range of motion deficit and TROM deficit our elite female handball players seem not at risk for shoulder injuries. Prospective studies are needed to support the belief that a DCR below 1 places the shoulder at risk for injury.

  17. Design of scanning motion control system for high-energy X-ray industrial CT

    International Nuclear Information System (INIS)

    Duan Liming

    2008-01-01

    A scanning motion control system was developed for the high-energy X-ray industrial computerized tomography (CT). The system consists of an industrial control computer, a counter card, a control card, servo drivers, servo motors, working platforms, gratings and control software. Based on windows driver model(WDM) mode, the composition of the driver pro- gram for the system was studied. Took the motor control card as an example, the method to develop the driver program was researched, and the intercourse process between the device driver program and the user-program was analyzed. The real-time control of the system was implemented using the WDM driver. The real-time performance and reliability of the system can satisfy the requirement of high-energy X-ray industrial CT. (authors)

  18. Multi-Objective Motion Control Optimization for the Bridge Crane System

    Directory of Open Access Journals (Sweden)

    Renxin Xiao

    2018-03-01

    Full Text Available A novel control algorithm combining the linear quadratic regulator (LQR control and trajectory planning (TP is proposed for the control of an underactuated crane system, targeting position adjustment and swing suppression. The TP is employed to control the swing angle within certain constraints, and the LQR is applied to achieve anti-disturbance. In order to improve the accuracy of the position control, a differential-integral control loop is applied. The weighted LQR matrices representing priorities of the state variables for the bridge crane motion are searched by the multi-objective genetic algorithm (MOGA. The stability proof is provided in order to validate the effectiveness of the proposed algorithm. Numerous simulation and experimental validations justify the feasibility of the proposed method.

  19. Model-Based Design of Brushless DC Motor Control and Motion Control Modelling for RoboCup SSL Robots

    OpenAIRE

    Li, Xiaotian

    2015-01-01

    Over the recent years, the RoboCup competition has grown popular and attracted more and more domestic and international universities, and the levels of the teams increase every year. In Small Size League (SSL) competition, besides a good strategy system, the precision of the robots’ actions is also of vital importance in order to achieve high performance. Thus, a highly accurate and stable motion control system is needed to drive the robots to move in accordance with the planned trajectory. C...

  20. Touch-free, gesture-based control of medical devices and software based on the leap motion controller.

    Science.gov (United States)

    Mauser, Stanislas; Burgert, Oliver

    2014-01-01

    There are several intra-operative use cases which require the surgeon to interact with medical devices. We used the Leap Motion Controller as input device and implemented two use-cases: 2D-Interaction (e.g. advancing EPR data) and selection of a value (e.g. room illumination brightness). The gesture detection was successful and we mapped its output to several devices and systems.

  1. Micro Aerial Vehicle (MAV Flapping Motion Control Using an Immune Network with Different Immune Factors

    Directory of Open Access Journals (Sweden)

    Liguo Weng

    2013-08-01

    Full Text Available This paper proposes a novel Neural-Immunology/Memory Network to address the problem of motion control for flapping-wing Micro Aerial Vehicles (MAVs. This network is inspired by the human memory system as well as the immune system, and it is effective in attenuating the system errors and other lumped system uncertainties. In contrast to most existing Neural Networks, the convergence of this proposed Neural-Immunology/Memory Network can be theoretically proven. Both analyses and simulations that are based on different immune factors show that the proposed control method is effective in dealing with external disturbances, system nonlinearities, uncertainties and parameter variations.

  2. Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

    Directory of Open Access Journals (Sweden)

    Yuya Kitaguchi

    2015-10-01

    Full Text Available Mechanical methods for single-molecule control have potential for wide application in nanodevices and machines. Here we demonstrate the operation of a single-molecule switch made functional by the motion of a phenyl ring, analogous to the lever in a conventional toggle switch. The switch can be actuated by dual triggers, either by a voltage pulse or by displacement of the electrode, and electronic manipulation of the ring by chemical substitution enables rational control of the on-state conductance. Owing to its simple mechanics, structural robustness, and chemical accessibility, we propose that phenyl rings are promising components in mechanical molecular devices.

  3. Oblique-wing research airplane motion simulation with decoupling control laws

    Science.gov (United States)

    Kempel, Robert W.; Mc Neill, Walter E.; Maine, Trindel A.

    1988-01-01

    A large piloted vertical motion simulator was used to assess the performance of a preliminary decoupling control law for an early version of the F-8 oblique wing research demonstrator airplane. Evaluations were performed for five discrete flight conditions, ranging from low-altitude subsonic Mach numbers to moderate-altitude supersonic Mach numbers. Asymmetric sideforce as a function of angle of attack was found to be the primary cause of both the lateral acceleration noted in pitch and the tendency to roll into left turns and out of right turns. The flight control system was shown to be effective in generally decoupling the airplane and reducing the lateral acceleration in pitch maneuvers.

  4. Control of motion stability of the line tracer robot using fuzzy logic and kalman filter

    Science.gov (United States)

    Novelan, M. S.; Tulus; Zamzami, E. M.

    2018-03-01

    Setting of motion and balance line tracer robot two wheels is actually a combination of a two-wheeled robot balance concept and the concept of line follower robot. The main objective of this research is to maintain the robot in an upright and can move to follow the line of the Wizard while maintaining balance. In this study the motion balance system on line tracer robot by considering the presence of a noise, so that it takes the estimator is used to mengestimasi the line tracer robot motion. The estimation is done by the method of Kalman Filter and the combination of Fuzzy logic-Fuzzy Kalman Filter called Kalman Filter, as well as optimal smooting. Based on the results of the study, the value of the output of the fuzzy results obtained from the sensor input value has been filtered before entering the calculation of the fuzzy. The results of the output of the fuzzy logic hasn’t been able to control dc motors are well balanced at the moment to be able to run. The results of the fuzzy logic by using membership function of triangular membership function or yet can control with good dc motor movement in order to be balanced

  5. Using unconstrained tongue motion as an alternative control mechanism for wheeled mobility.

    Science.gov (United States)

    Huo, Xueliang; Ghovanloo, Maysam

    2009-06-01

    Tongue drive system (TDS) is a tongue-operated, minimally invasive, unobtrusive, noncontact, and wireless assistive technology that infers users' intentions by detecting and classifying their voluntary tongue motions, and translating them to user-defined commands. We have developed customized interface circuitry between an external TDS (eTDS) prototype and a commercial powered wheelchair (PWC) as well as three control strategies to evaluate the tongue motion as an alternative control input for wheeled mobility. We tested the eTDS performance in driving PWCs on 12 able-bodied human subjects, of which 11 were novice. The results showed that all subjects could complete navigation tasks by operating the PWC using their tongue motions. Despite little prior experience, the average time using the eTDS and the tongue was only approximately three times longer than using a joystick and the fingers. Navigation time was strongly dependant on the number of issued commands, which reduced by gaining experience. Particularly, the unintended issued commands (the Midas touch problem) were rare, demonstrating the effectiveness of the tongue tracking and external magnetic field cancellation algorithms as well as the safety of the TDS for wheeled mobility.

  6. Time-domain prefilter design for enhanced tracking and vibration suppression in machine motion control

    Science.gov (United States)

    Cole, Matthew O. T.; Shinonawanik, Praween; Wongratanaphisan, Theeraphong

    2018-05-01

    Structural flexibility can impact negatively on machine motion control systems by causing unmeasured positioning errors and vibration at locations where accurate motion is important for task execution. To compensate for these effects, command signal prefiltering may be applied. In this paper, a new FIR prefilter design method is described that combines finite-time vibration cancellation with dynamic compensation properties. The time-domain formulation exploits the relation between tracking error and the moment values of the prefilter impulse response function. Optimal design solutions for filters having minimum H2 norm are derived and evaluated. The control approach does not require additional actuation or sensing and can be effective even without complete and accurate models of the machine dynamics. Results from implementation and testing on an experimental high-speed manipulator having a Delta robot architecture with directionally compliant end-effector are presented. The results show the importance of prefilter moment values for tracking performance and confirm that the proposed method can achieve significant reductions in both peak and RMS tracking error, as well as settling time, for complex motion patterns.

  7. Enhancing the stabilization of aircraft pitch motion control via intelligent and classical method

    Science.gov (United States)

    Lukman, H.; Munawwarah, S.; Azizan, A.; Yakub, F.; Zaki, S. A.; Rasid, Z. A.

    2017-12-01

    The pitching movement of an aircraft is very important to ensure passengers are intrinsically safe and the aircraft achieve its maximum stability. The equations governing the motion of an aircraft are a complex set of six nonlinear coupled differential equations. Under certain assumptions, it can be decoupled and linearized into longitudinal and lateral equations. Pitch control is a longitudinal problem and thus, only the longitudinal dynamics equations are involved in this system. It is a third order nonlinear system, which is linearized about the operating point. The system is also inherently unstable due to the presence of a free integrator. Because of this, a feedback controller is added in order to solve this problem and enhance the system performance. This study uses two approaches in designing controller: a conventional controller and an intelligent controller. The pitch control scheme consists of proportional, integral and derivatives (PID) for conventional controller and fuzzy logic control (FLC) for intelligent controller. Throughout the paper, the performance of the presented controllers are investigated and compared based on the common criteria of step response. Simulation results have been obtained and analysed by using Matlab and Simulink software. The study shows that FLC controller has higher ability to control and stabilize the aircraft's pitch angle as compared to PID controller.

  8. Controlled Folding, Motional, and Constitutional Dynamic Processes of Polyheterocyclic Molecular Strands.

    Science.gov (United States)

    Barboiu, Mihail; Stadler, Adrian-Mihail; Lehn, Jean-Marie

    2016-03-18

    General design principles have been developed for the control of the structural features of polyheterocyclic strands and their effector-modulated shape changes. Induced defined molecular motions permit designed enforcement of helical as well as linear molecular shapes. The ability of such molecular strands to bind metal cations allows the generation of coiling/uncoiling processes between helically folded and extended linear states. Large molecular motions are produced on coordination of metal ions, which may be made reversible by competition with an ancillary complexing agent and fueled by sequential acid/base neutralization energy. The introduction of hydrazone units into the strands confers upon them constitutional dynamics, whereby interconversion between different strand compositions is achieved through component exchange. These features have relevance for nanomechanical devices. We present a morphological and functional analysis of such systems developed in our laboratories. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Friction control using ultrasonic oscillation for rolling-element linear-motion guide

    International Nuclear Information System (INIS)

    Oiwa, Takaaki

    2006-01-01

    This article reports a friction-control method for rolling-element linear-motion guides used for precision positioning. In general, static friction greater than dynamic friction generates stick-slip motion and diminishes the positioning accuracy. Two ultrasonic actuators excite both the rail and the carriage of the guide to give relative displacements to bearing surfaces. In order to effectively propagate the vibration over the entire rail without damping, the actuator drives at that frequency with a half wavelength corresponding to the distances between the rail mounting bolts. This also minimizes undesirable vibration of the machine structure. Moreover, the bearing surfaces of the carriage are resonated by a second ultrasonic actuator. The experiments using a force sensor showed that the static and dynamic friction forces were reduced by approximately 25% at any place on the 600-mm-long rail. Moreover, excitation only at very low velocity decreased the static friction peak

  10. Controlling Urban Lighting by Human Motion Patterns results from a full Scale Experiment

    DEFF Research Database (Denmark)

    Poulsen, Esben Skouboe; Andersen, Hans Jørgen; Jensen, Ole B.

    2012-01-01

    This paper presents a full-scale experiment investigating the use of human motion intensities as input for interactive illumination of a town square in the city of Aalborg in Denmark. As illuminators sixteen 3.5 meter high RGB LED lamps were used. The activity on the square was monitored by three...... thermal cameras and analysed by computer vision software from which motion intensity maps and peoples trajectories were estimated and used as input to control the interactive illumination. The paper introduces a 2-layered interactive light strategy addressing ambient and effect illumination criteria...... totally four light scenarios were designed and tested. The result shows that in general people immersed in the street lighting did not notice that the light changed according to their presence or actions, but people watching from the edge of the square noticed the interaction between the illumination...

  11. The relationship of motion sickness susceptibility to learned autonomic control for symptom suppression

    Science.gov (United States)

    Cowings, P. S.; Toscano, W. B.

    1982-01-01

    Twenty-four men were randomly assigned to four equal groups matched in terms of their Coriolis Sickness Susceptibility Index (CSSI). Two groups of subjects were highly susceptible to motion sickness, and two groups were moderately susceptible. All subjects were given six C551 tests at 5-d intervals. Treatment Groups I (highly susceptible) and II (moderately susceptible) were taught to control their autonomic responses, using a training method called autogenic-feedback training (AFT) before the third, fourth, and fifth CSSI tests. Control groups III (highly susceptible) and IV (moderately susceptible) received no treatment. Results showed that both treatment groups significantly improved performance on CSSI tests after training; neither of the control groups changed significantly. Highly and moderately susceptible subjects in the two treatment groups improved at comparable rates. Highly susceptible control group subjects did not habituate across tests as readily as the moderately susceptible controls.

  12. Neural Network Control for the Linear Motion of a Spherical Mobile Robot

    Directory of Open Access Journals (Sweden)

    Yao Cai

    2011-09-01

    Full Text Available This paper discussed the stabilization and position tracking control of the linear motion of an underactuated spherical robot. By considering the actuator dynamics, a complete dynamic model of the robot is deduced, which is a complex third order, two variables nonlinear differential system and those two variables have strong coupling due to the mechanical structure of the robot. Different from traditional treatments, no linearization is applied to this system but a single‐input multiple‐output PID (SIMO_PID controller is designed by adopting a six‐input single‐ output CMAC_GBF (Cerebellar Model Articulation Controller with General Basis Function neural network to compensate the actuator nonlinearity and the credit assignment (CA learning method to obtain faster convergence of CMAC_GBF. The proposed controller is generalizable to other single‐input multiple‐output system with good real‐time capability. Simulations in Matlab are used to validate the control effects.

  13. Motion coordination for VTOL unmanned aerial vehicles attitude synchronisation and formation control

    CERN Document Server

    Abdessameud, Abdelkader

    2013-01-01

    Motion Coordination for VTOL Unmanned Aerial Vehicles develops new control design techniques for the distributed coordination of a team of autonomous unmanned aerial vehicles. In particular, it provides new control design approaches for the attitude synchronization of a formation of rigid body systems. In addition, by integrating new control design techniques with some concepts from nonlinear control theory and multi-agent systems, it presents  a new theoretical framework for the formation control of a class of under-actuated aerial vehicles capable of vertical take-off and landing. Several practical problems related to the systems’ inputs, states measurements, and  restrictions on the interconnection  topology  between the aerial vehicles in the team  are addressed. Worked examples with sufficient details and simulation results are provided to illustrate the applicability and effectiveness of the theoretical results discussed in the book. The material presented is primarily intended for researchers an...

  14. The use of active breathing control (ABC) to reduce margin for breathing motion

    International Nuclear Information System (INIS)

    Wong, John W.; Sharpe, Michael B.; Jaffray, David A.; Kini, Vijay R.; Robertson, John M.; Stromberg, Jannifer S.; Martinez, Alavro A.

    1999-01-01

    Purpose: For tumors in the thorax and abdomen, reducing the treatment margin for organ motion due to breathing reduces the volume of normal tissues that will be irradiated. A higher dose can be delivered to the target, provided that the risk of marginal misses is not increased. To ensure safe margin reduction, we investigated the feasibility of using active breathing control (ABC) to temporarily immobilize the patient's breathing. Treatment planning and delivery can then be performed at identical ABC conditions with minimal margin for breathing motion. Methods and Materials: An ABC apparatus is constructed consisting of 2 pairs of flow monitor and scissor valve, 1 each to control the inspiration and expiration paths to the patient. The patient breathes through a mouth-piece connected to the ABC apparatus. The respiratory signal is processed continuously, using a personal computer that displays the changing lung volume in real-time. After the patient's breathing pattern becomes stable, the operator activates ABC at a preselected phase in the breathing cycle. Both valves are then closed to immobilize breathing motion. Breathing motion of 12 patients were held with ABC to examine their acceptance of the procedure. The feasibility of applying ABC for treatment was tested in 5 patients by acquiring volumetric scans with a spiral computed tomography (CT) scanner during active breath-hold. Two patients had Hodgkin's disease, 2 had metastatic liver cancer, and 1 had lung cancer. Two intrafraction ABC scans were acquired at the same respiratory phase near the end of normal or deep inspiration. An additional ABC scan near the end of normal expiration was acquired for 2 patients. The ABC scans were also repeated 1 week later for a Hodgkin's patient. In 1 liver patient, ABC scans were acquired at 7 different phases of the breathing cycle to facilitate examination of the liver motion associated with ventilation. Contours of the lungs and livers were outlined when applicable

  15. Fuzzy robust nonlinear control approach for electro-hydraulic flight motion simulator

    Directory of Open Access Journals (Sweden)

    Han Songshan

    2015-02-01

    Full Text Available A fuzzy robust nonlinear controller for hydraulic rotary actuators in flight motion simulators is proposed. Compared with other three-order models of hydraulic rotary actuators, the proposed controller based on first-order nonlinear model is more easily applied in practice, whose control law is relatively simple. It not only does not need high-order derivative of desired command, but also does not require the feedback signals of velocity, acceleration and jerk of hydraulic rotary actuators. Another advantage is that it does not rely on any information of friction, inertia force and external disturbing force/torque, which are always difficult to resolve in flight motion simulators. Due to the special composite vane seals of rectangular cross-section and goalpost shape used in hydraulic rotary actuators, the leakage model is more complicated than that of traditional linear hydraulic cylinders. Adaptive multi-input single-output (MISO fuzzy compensators are introduced to estimate nonlinear uncertain functions about leakage and bulk modulus. Meanwhile, the decomposition of the uncertainties is used to reduce the total number of fuzzy rules. Different from other adaptive fuzzy compensators, a discontinuous projection mapping is employed to guarantee the estimation process to be bounded. Furthermore, with a sufficient number of fuzzy rules, the controller theoretically can guarantee asymptotic tracking performance in the presence of the above uncertainties, which is very important for high-accuracy tracking control of flight motion simulators. Comparative experimental results demonstrate the effectiveness of the proposed algorithm, which can guarantee transient performance and better final accurate tracking in the presence of uncertain nonlinearities and parametric uncertainties.

  16. Control of self-motion in dynamic fluids: fish do it differently from bees.

    Science.gov (United States)

    Scholtyssek, Christine; Dacke, Marie; Kröger, Ronald; Baird, Emily

    2014-05-01

    To detect and avoid collisions, animals need to perceive and control the distance and the speed with which they are moving relative to obstacles. This is especially challenging for swimming and flying animals that must control movement in a dynamic fluid without reference from physical contact to the ground. Flying animals primarily rely on optic flow to control flight speed and distance to obstacles. Here, we investigate whether swimming animals use similar strategies for self-motion control to flying animals by directly comparing the trajectories of zebrafish (Danio rerio) and bumblebees (Bombus terrestris) moving through the same experimental tunnel. While moving through the tunnel, black and white patterns produced (i) strong horizontal optic flow cues on both walls, (ii) weak horizontal optic flow cues on both walls and (iii) strong optic flow cues on one wall and weak optic flow cues on the other. We find that the mean speed of zebrafish does not depend on the amount of optic flow perceived from the walls. We further show that zebrafish, unlike bumblebees, move closer to the wall that provides the strongest visual feedback. This unexpected preference for strong optic flow cues may reflect an adaptation for self-motion control in water or in environments where visibility is limited. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Motion planning and synchronized control of the dental arch generator of the tooth-arrangement robot.

    Science.gov (United States)

    Jiang, Jin-Gang; Zhang, Yong-De

    2013-03-01

    The traditional, manual method of reproducing the dental arch form is prone to numerous random errors caused by human factors. The purpose of this study was to investigate the automatic acquisition of the dental arch and implement the motion planning and synchronized control of the dental arch generator of the multi-manipulator tooth-arrangement robot for use in full denture manufacture. First, the mathematical model of the dental arch generator was derived. Then the kinematics and control point position of the dental arch generator of the tooth arrangement robot were calculated and motion planning of each control point was analysed. A hardware control scheme is presented, based on the industrial personal computer and control card PC6401. In order to gain single-axis, precise control of the dental arch generator, we studied the control pulse realization of high-resolution timing. Real-time, closed-loop, synchronous control was applied to the dental arch generator. Experimental control of the dental arch generator and preliminary tooth arrangement were gained by using the multi-manipulator tooth-arrangement robotic system. The dental arch generator can automatically generate a dental arch to fit a patient according to the patient's arch parameters. Repeated positioning accuracy is 0.12 mm for the slipways that drive the dental arch generator. The maximum value of single-point error is 1.83 mm, while the arc-width direction (x axis) is -33.29 mm. A novel system that generates the dental arch has been developed. The traditional method of manually determining the dental arch may soon be replaced by a robot to assist in generating a more individual dental arch. The system can be used to fabricate full dentures and bend orthodontic wires. Copyright © 2012 John Wiley & Sons, Ltd.

  18. Models of Postural Control: Shared Variance in Joint and COM Motions.

    Directory of Open Access Journals (Sweden)

    Melissa C Kilby

    Full Text Available This paper investigated the organization of the postural control system in human upright stance. To this aim the shared variance between joint and 3D total body center of mass (COM motions was analyzed using multivariate canonical correlation analysis (CCA. The CCA was performed as a function of established models of postural control that varied in their joint degrees of freedom (DOF, namely, an inverted pendulum ankle model (2DOF, ankle-hip model (4DOF, ankle-knee-hip model (5DOF, and ankle-knee-hip-neck model (7DOF. Healthy young adults performed various postural tasks (two-leg and one-leg quiet stances, voluntary AP and ML sway on a foam and rigid surface of support. Based on CCA model selection procedures, the amount of shared variance between joint and 3D COM motions and the cross-loading patterns we provide direct evidence of the contribution of multi-DOF postural control mechanisms to human balance. The direct model fitting of CCA showed that incrementing the DOFs in the model through to 7DOF was associated with progressively enhanced shared variance with COM motion. In the 7DOF model, the first canonical function revealed more active involvement of all joints during more challenging one leg stances and dynamic posture tasks. Furthermore, the shared variance was enhanced during the dynamic posture conditions, consistent with a reduction of dimension. This set of outcomes shows directly the degeneracy of multivariate joint regulation in postural control that is influenced by stance and surface of support conditions.

  19. Centralized motion control of a linear tooth belt drive: Analysis of the performance and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, M.

    2010-07-01

    A centralized robust position control for an electrical driven tooth belt drive is designed in this doctoral thesis. Both a cascaded control structure and a PID based position controller are discussed. The performance and the limitations of the system are analyzed and design principles for the mechanical structure and the control design are given. These design principles are also suitable for most of the motion control applications, where mechanical resonance frequencies and control loop delays are present. One of the major challenges in the design of a controller for machinery applications is that the values of the parameters in the system model (parameter uncertainty) or the system model it self (non-parametric uncertainty) are seldom known accurately in advance. In this thesis a systematic analysis of the parameter uncertainty of the linear tooth beltdrive model is presented and the effect of the variation of a single parameter on the performance of the total system is shown. The total variation of the model parameters is taken into account in the control design phase using a Quantitative Feedback Theory (QFT). The thesis also introduces a new method to analyze reference feedforward controllers applying the QFT. The performance of the designed controllers is verified by experimental measurements. The measurements confirm the control design principles that are given in this thesis. (orig.)

  20. Modeling of the motion of automobile elastic wheel in real-time for creation of wheeled vehicles motion control electronic systems

    Science.gov (United States)

    Balakina, E. V.; Zotov, N. M.; Fedin, A. P.

    2018-02-01

    Modeling of the motion of the elastic wheel of the vehicle in real-time is used in the tasks of constructing different models in the creation of wheeled vehicles motion control electronic systems, in the creation of automobile stand-simulators etc. The accuracy and the reliability of simulation of the parameters of the wheel motion in real-time when rolling with a slip within the given road conditions are determined not only by the choice of the model, but also by the inaccuracy and instability of the numerical calculation. It is established that the inaccuracy and instability of the calculation depend on the size of the step of integration and the numerical method being used. The analysis of these inaccuracy and instability when wheel rolling with a slip was made and recommendations for reducing them were developed. It is established that the total allowable range of steps of integration is 0.001.0.005 s; the strongest instability is manifested in the calculation of the angular and linear accelerations of the wheel; the weakest instability is manifested in the calculation of the translational velocity of the wheel and moving of the center of the wheel; the instability is less at large values of slip angle and on more slippery surfaces. A new method of the average acceleration is suggested, which allows to significantly reduce (up to 100%) the manifesting of instability of the solution in the calculation of all parameters of motion of the elastic wheel for different braking conditions and for the entire range of steps of integration. The results of research can be applied to the selection of control algorithms in vehicles motion control electronic systems and in the testing stand-simulators

  1. Cartesian Control of a 3-DOF Electro-Pneumatic Actuated Motion Platform with Exteroceptive Pose Measurement

    Directory of Open Access Journals (Sweden)

    Eduardo Izaguirre

    2011-09-01

    Full Text Available This paper presents a kinematic cartesian control scheme of 3 degree of freedom parallel robot driven by electro-pneumatic actuators based on exteroceptive pose measurement system. The inverse kinematics model is used to obtain the desired joint position coordinates from the time-varying trajectory given in task space. The proposal cascade control scheme in task space is based in two loops, the inner loop consisting in a decoupled joint position control and the outer loop which is designed to obtain an appropriate task space trajectory tracking. In order to avoid the on-line computation of direct kinematics an arrangement of inertial sensor and optical encoders are employed to provide the accurate pose measurement of end-effector. The experiment's results demonstrate the great performance of the proposed control scheme in industrial motion tracking application.

  2. Hopping system control with an approximated dynamics model and upper-body motion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyang Jun; Oh, Jun Ho [KAIST, Daejeon (Korea, Republic of)

    2015-11-15

    A hopping system is highly non-linear due to the nature of its dynamics, which has alternating phases in a cycle, flight and stance phases and related transitions. Every control method that stabilizes the hopping system satisfies the Poincaré stability condition. At the Poincaré section, a hopping system cycle is considered as discrete sectional data set. By controlling the sectional data in a discrete control form, we can generate a stable hopping cycle. We utilize phase-mapping matrices to build a Poincaré return map by approximating the dynamics of the hopping system with SLIP model. We can generate various Poincaré stable gait patterns with the approximated discrete control form which uses upper-body motions as inputs.

  3. Wireless control system for two-axis linear oscillating motion applying CBR technology

    Science.gov (United States)

    Kuzyakov, O. N.; Andreeva, M. A.

    2018-03-01

    The paper presents the aspects of elaborating a movement control system. The system is to implement determination of movement characteristics of the object controlled, which performs an oscillating linear motion in a two-axis direction. The system has an electronic-optical principle of action: light receivers are attached to a controlled object, and a laser light emitter is attached to a static construction. While the object performs movement along the construction, the light emitter signal is registered by light receivers, based on which determination of the object position and characteristic of its movement are performed. An algorithm of system implementation is elaborated. Signal processing is performed on the basis of the case-based reasoning method. The system is to be used in machine-building industry in controlling relative displacement of the dynamic object or its assembly.

  4. Design and Implementation an Autonomous Humanoid Robot Based on Fuzzy Rule-Based Motion Controller

    Directory of Open Access Journals (Sweden)

    Mohsen Taheri

    2010-04-01

    Full Text Available Research on humanoid robotics in Mechatronics and Automation Laboratory, Electrical and Computer Engineering, Islamic Azad University Khorasgan branch (Isfahan of Iran was started at
    the beginning of this decade. Various research prototypes for humanoid robots have been designed and are going through evolution over these years. This paper describes the hardware and software design of the kid size humanoid robot systems of the PERSIA Team in 2009. The robot has 20 actuated degrees of freedom based on Hitec HSR898. In this paper we have tried to focus on areas such as mechanical structure, Image processing unit, robot controller, Robot AI and behavior
    learning. In 2009, our developments for the Kid size humanoid robot include: (1 the design and construction of our new humanoid robots (2 the design and construction of a new hardware and software controller to be used in our robots. The project is described in two main parts: Hardware and Software. The software is developed a robot application which consists walking controller, autonomous motion robot, self localization base on vision and Particle Filter, local AI, Trajectory Planning, Motion Controller and Network. The hardware consists of the mechanical structure and the driver circuit board. Each robot is able to walk, fast walk, pass, kick and dribble when it catches
    the ball. These humanoids have been successfully participating in various robotic soccer competitions. This project is still in progress and some new interesting methods are described in the current report.

  5. Optimal Control of Holding Motion by Nonprehensile Two-Cooperative-Arm Robot

    Directory of Open Access Journals (Sweden)

    Changan Jiang

    2016-01-01

    Full Text Available Recently, more researchers have focused on nursing-care assistant robot and placed their hope on it to solve the shortage problem of the caregivers in hospital or nursing home. In this paper, a nonprehensile two-cooperative-arm robot is considered to realize holding motion to keep a two-rigid-link object (regarded as a care-receiver stable on the robot arms. By applying Newton-Euler equations of motion, dynamic model of the object is obtained. In this model, for describing interaction behavior between object and robot arms in the normal direction, a viscoelastic model is employed to represent the normal forces. Considering existence of friction between object and robot arms, LuGre dynamic model is applied to describe the friction. Based on the obtained model, an optimal regulator is designed to control the holding motion of two-cooperative-arm robot. In order to verify the effectiveness of the proposed method, simulation results are shown.

  6. Content and structure of knowledge base used for virtual control of android arm motion in specified environment

    Science.gov (United States)

    Pritykin, F. N.; Nebritov, V. I.

    2018-01-01

    The paper presents the configuration of knowledge base necessary for intelligent control of android arm mechanism motion with different positions of certain forbidden regions taken into account. The present structure of the knowledge base characterizes the past experience of arm motion synthesis in the vector of velocities with due regard for the known obstacles. This structure also specifies its intrinsic properties. Knowledge base generation is based on the study of the arm mechanism instantaneous states implementations. Computational experiments connected with the virtual control of android arm motion with known forbidden regions using the developed knowledge base are introduced. Using the developed knowledge base to control virtually the arm motion reduces the time of test assignments calculation. The results of the research can be used in developing control systems of autonomous android robots in the known in advance environment.

  7. Theoretical Insights Reveal Novel Motions in Csk's SH3 Domain That Control Kinase Activation.

    Directory of Open Access Journals (Sweden)

    Sulyman Barkho

    Full Text Available The Src family of tyrosine kinases (SFKs regulate numerous aspects of cell growth and differentiation and are under the principal control of the C-terminal Src Kinase (Csk. Although Csk and SFKs share conserved kinase, SH2 and SH3 domains, they differ considerably in three-dimensional structure, regulatory mechanism, and the intrinsic kinase activities. Although the SH2 and SH3 domains are known to up- or down-regulate tyrosine kinase function, little is known about the global motions in the full-length kinase that govern these catalytic variations. We use a combination of accelerated Molecular Dynamics (aMD simulations and experimental methods to provide a new view of functional motions in the Csk scaffold. These computational studies suggest that high frequency vibrations in the SH2 domain are coupled through the N-terminal lobe of the kinase domain to motions in the SH3 domain. The effects of these reflexive movements on the kinase domain can be viewed using both Deuterium Exchange Mass Spectrometry (DXMS and steady-state kinetic methods. Removal of several contacts, including a crystallographically unobserved N-terminal segment, between the SH3 and kinase domains short-circuit these coupled motions leading to reduced catalytic efficiency and stability of N-lobe motifs within the kinase domain. The data expands the model of Csk's activation whereby separate domains productively interact with two diametrically opposed surfaces of the kinase domain. Such reversible transitions may organize the active structure of the tyrosine kinase domain of Csk.

  8. Imparting motion to a test object such as a motor vehicle in a controlled fashion

    OpenAIRE

    2011-01-01

    An apparatus imparts motion to a test object such as a motor vehicle in a controlled fashion. A base has mounted on it a linear electromagnetic motor having a first end and a second end, the first end being connected to the base. A pneumatic cylinder and piston combination have a first end and a second end, the first end connected to the base so that the pneumatic cylinder and piston combination is generally parallel with the linear electromagnetic motor. The second ends of the linear electro...

  9. Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

    Science.gov (United States)

    Deng, Jie; Xie, Yaoqin

    2013-01-01

    The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy. PMID:24093100

  10. Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

    Directory of Open Access Journals (Sweden)

    Rongmao Li

    2013-01-01

    Full Text Available The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy.

  11. Investigation of a Ball Screw Feed Drive System Based on Dynamic Modeling for Motion Control

    Directory of Open Access Journals (Sweden)

    Yi-Cheng Huang

    2017-06-01

    Full Text Available This paper examines the frequency response relationship between the ball screw nut preload, ball screw torsional stiffness variations and table mass effect for a single-axis feed drive system. Identification for the frequency response of an industrial ball screw drive system is very important for the precision motion when the vibration modes of the system are critical for controller design. In this study, there is translation and rotation modes of a ball screw feed drive system when positioning table is actuated by a servo motor. A lumped dynamic model to study the ball nut preload variation and torsional stiffness of the ball screw drive system is derived first. The mathematical modeling and numerical simulation provide the information of peak frequency response as the different levels of ball nut preload, ball screw torsional stiffness and table mass. The trend of increasing preload will indicate the abrupt peak change in frequency response spectrum analysis in some mode shapes. This study provides an approach to investigate the dynamic frequency response of a ball screw drive system, which provides significant information for better control performance when precise motion control is concerned.

  12. Linear Motor Motion Control Experiment System Design Based on LabVIEW

    Directory of Open Access Journals (Sweden)

    Cuixian He

    2018-01-01

    Full Text Available In order to meet the needs of experimental training of electrical information industry, a linear motor motion experiment system based on LabVIEW was developed. This system is based on the STM32F103ZET6 system processor controller, a state signal when the motor moves through the grating encoder feedback controller to form a closed loop, through the RS232 serial port communication with the host computer, the host computer is designed in the LabVIEW interactive environment monitoring software. Combined with the modular design concept proposed overall program, given the detailed hardware circuit, targeted for the software function design, to achieve man-machine interface. The system control of high accuracy, good stability, meet the training requirements for laboratory equipment, but also as a reference embodiment of the linear motor monitoring system.

  13. Leap Motion Gesture Control With Carestream Software in the Operating Room to Control Imaging: Installation Guide and Discussion.

    Science.gov (United States)

    Pauchot, Julien; Di Tommaso, Laetitia; Lounis, Ahmed; Benassarou, Mourad; Mathieu, Pierre; Bernot, Dominique; Aubry, Sébastien

    2015-12-01

    Nowadays, routine cross-sectional imaging viewing during a surgical procedure requires physical contact with an interface (mouse or touch-sensitive screen). Such contact risks exposure to aseptic conditions and causes loss of time. Devices such as the recently introduced Leap Motion (Leap Motion Society, San Francisco, CA), which enables interaction with the computer without any physical contact, are of wide interest in the field of surgery, but configuration and ergonomics are key challenges for the practitioner, imaging software, and surgical environment. This article aims to suggest an easy configuration of Leap Motion on a PC for optimized use with Carestream Vue PACS v11.3.4 (Carestream Health, Inc, Rochester, NY) using a plug-in (to download at https://drive.google.com/open?id=0B_F4eBeBQc3yNENvTXlnY09qS00&authuser=0) and a video tutorial (https://www.youtube.com/watch?v=yVPTgxg-SIk). Videos of surgical procedure and discussion about innovative gesture control technology and its various configurations are provided in this article. © The Author(s) 2015.

  14. A Randomized Controlled Trial of Lorazepam to Reduce Liver Motion in Patients Receiving Upper Abdominal Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, Derek S.; Voncken, Francine E.M.; Tse, Regina V. [Princess Margaret Cancer Centre, University Health Network, Department of Radiation Oncology, University of Toronto, Toronto (Canada); Sykes, Jenna [Department of Biostatistics, Princess Margaret Cancer Centre, University Health Network, Toronto (Canada); Wong, Rebecca K.S.; Dinniwell, Rob E.; Kim, John; Ringash, Jolie; Brierley, James D.; Cummings, Bernard J.; Brade, Anthony [Princess Margaret Cancer Centre, University Health Network, Department of Radiation Oncology, University of Toronto, Toronto (Canada); Dawson, Laura A., E-mail: laura.dawson@rmp.uhn.on.ca [Princess Margaret Cancer Centre, University Health Network, Department of Radiation Oncology, University of Toronto, Toronto (Canada)

    2013-12-01

    Purpose: Reduction of respiratory motion is desirable to reduce the volume of normal tissues irradiated, to improve concordance of planned and delivered doses, and to improve image guided radiation therapy (IGRT). We hypothesized that pretreatment lorazepam would lead to a measurable reduction of liver motion. Methods and Materials: Thirty-three patients receiving upper abdominal IGRT were recruited to a double-blinded randomized controlled crossover trial. Patients were randomized to 1 of 2 study arms: arm 1 received lorazepam 2 mg by mouth on day 1, followed by placebo 4 to 8 days later; arm 2 received placebo on day 1, followed by lorazepam 4 to 8 days later. After tablet ingestion and daily radiation therapy, amplitude of liver motion was measured on both study days. The primary outcomes were reduction in craniocaudal (CC) liver motion using 4-dimensional kV cone beam computed tomography (CBCT) and the proportion of patients with liver motion ≤5 mm. Secondary endpoints included motion measured with cine magnetic resonance imaging and kV fluoroscopy. Results: Mean relative and absolute reduction in CC amplitude with lorazepam was 21% and 2.5 mm respectively (95% confidence interval [CI] 1.1-3.9, P=.001), as assessed with CBCT. Reduction in CC amplitude to ≤5 mm residual liver motion was seen in 13% (95% CI 1%-25%) of patients receiving lorazepam (vs 10% receiving placebo, P=NS); 65% (95% CI 48%-81%) had reduction in residual CC liver motion to ≤10 mm (vs 52% with placebo, P=NS). Patients with large respiratory movement and patients who took lorazepam ≥60 minutes before imaging had greater reductions in liver CC motion. Mean reductions in liver CC amplitude on magnetic resonance imaging and fluoroscopy were nonsignificant. Conclusions: Lorazepam reduces liver motion in the CC direction; however, average magnitude of reduction is small, and most patients have residual motion >5 mm.

  15. Radial polar histogram: obstacle avoidance and path planning for robotic cognition and motion control

    Science.gov (United States)

    Wang, Po-Jen; Keyawa, Nicholas R.; Euler, Craig

    2012-01-01

    In order to achieve highly accurate motion control and path planning for a mobile robot, an obstacle avoidance algorithm that provided a desired instantaneous turning radius and velocity was generated. This type of obstacle avoidance algorithm, which has been implemented in California State University Northridge's Intelligent Ground Vehicle (IGV), is known as Radial Polar Histogram (RPH). The RPH algorithm utilizes raw data in the form of a polar histogram that is read from a Laser Range Finder (LRF) and a camera. A desired open block is determined from the raw data utilizing a navigational heading and an elliptical approximation. The left and right most radii are determined from the calculated edges of the open block and provide the range of possible radial paths the IGV can travel through. In addition, the calculated obstacle edge positions allow the IGV to recognize complex obstacle arrangements and to slow down accordingly. A radial path optimization function calculates the best radial path between the left and right most radii and is sent to motion control for speed determination. Overall, the RPH algorithm allows the IGV to autonomously travel at average speeds of 3mph while avoiding all obstacles, with a processing time of approximately 10ms.

  16. Modular Estimation Strategy of Vehicle Dynamic Parameters for Motion Control Applications

    Directory of Open Access Journals (Sweden)

    Rawash Mustafa

    2018-01-01

    Full Text Available The presence of motion control or active safety systems in vehicles have become increasingly important for improving vehicle performance and handling and negotiating dangerous driving situations. The performance of such systems would be improved if combined with knowledge of vehicle dynamic parameters. Since some of these parameters are difficult to measure, due to technical or economic reasons, estimation of those parameters might be the only practical alternative. In this paper, an estimation strategy of important vehicle dynamic parameters, pertaining to motion control applications, is presented. The estimation strategy is of a modular structure such that each module is concerned with estimating a single vehicle parameter. Parameters estimated include: longitudinal, lateral, and vertical tire forces – longitudinal velocity – vehicle mass. The advantage of this strategy is its independence of tire parameters or wear, road surface condition, and vehicle mass variation. Also, because of its modular structure, each module could be later updated or exchanged for a more effective one. Results from simulations on a 14-DOF vehicle model are provided here to validate the strategy and show its robustness and accuracy.

  17. Wideband Motion Control by Position and Acceleration Input Based Disturbance Observer

    Science.gov (United States)

    Irie, Kouhei; Katsura, Seiichiro; Ohishi, Kiyoshi

    The disturbance observer can observe and suppress the disturbance torque within its bandwidth. Recent motion systems begin to spread in the society and they are required to have ability to contact with unknown environment. Such a haptic motion requires much wider bandwidth. However, since the conventional disturbance observer attains the acceleration response by the second order derivative of position response, the bandwidth is limited due to the derivative noise. This paper proposes a novel structure of a disturbance observer. The proposed disturbance observer uses an acceleration sensor for enlargement of bandwidth. Generally, the bandwidth of an acceleration sensor is from 1Hz to more than 1kHz. To cover DC range, the conventional position sensor based disturbance observer is integrated. Thus, the performance of the proposed Position and Acceleration input based disturbance observer (PADO) is superior to the conventional one. The PADO is applied to position control (infinity stiffness) and force control (zero stiffness). The numerical and experimental results show viability of the proposed method.

  18. Interactive motion-controlled games in the neurorehabilitation of adult post-stroke patients

    Directory of Open Access Journals (Sweden)

    Emilia Mikołajewska

    2015-08-01

    Emilia Mikołajewska Rehabilitation Clinic Military Clinical Hospital No. 10 and Polyclinic Bydgoszcz, Poland e-mail: e.mikolajewska@wp.pl, emiliam@cm.umk.pl www: http://emikolajewska.netstrefa.eu   Keywords: neurorehabilitation; physiotherapy; stroke; neurological deficit; therapeutic game.   Abstract   Despite efforts of scientists and clinicians stroke still constitutes one of the major causes of disability worldwide. Motion-controlled video games become increasingly common adjunct to the traditional physical therapy. Such games are usually available, low-cost, fun, and functional ways to increase everyday treatment possibilities, both in hospital, ambulatory and home settings. Research and scientific publications concerning this issue are still rare. Assessment how interactive motion-controlled games can be incorporated into current guidelines of the eclectic approach within neurorehabilitation of adult post-stroke survivors is key issue within contemporary neurorehabilitation of adults. Complementary use of such games may constitute another breakthrough both in in-patient and out-patient rehabilitation and care. This review aims at potential of aforementioned solutions and modalities for the rehabilitation of function in cases of stroke.

  19. Fault Structural Control on Earthquake Strong Ground Motions: The 2008 Wenchuan Earthquake as an Example

    Science.gov (United States)

    Zhang, Yan; Zhang, Dongli; Li, Xiaojun; Huang, Bei; Zheng, Wenjun; Wang, Yuejun

    2018-02-01

    Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction.

  20. A General Cognitive System Architecture Based on Dynamic Vision for Motion Control

    Directory of Open Access Journals (Sweden)

    Ernst D. Dickmanns

    2003-10-01

    Full Text Available Animation of spatio-temporal generic models for 3-D shape and motion of objects and subjects, based on feature sets evaluated in parallel from several image streams, is considered to be the core of dynamic vision. Subjects are a special kind of objects capable of sensing environmental parameters and of initiating own actions in combination with stored knowledge. Object / subject recognition and scene understanding are achieved on different levels and scales. Multiple objects are tracked individually in the image streams for perceiving their actual state ('here and now'. By analyzing motion of all relevant objects / subjects over a larger time scale on the level of state variables in the 'scene tree representation' known from computer graphics, the situation with respect to decision taking is assessed. Behavioral capabilities of subjects are represented explicitly on an abstract level for characterizing their potential behaviors. These are generated by stereotypical feed-forward and feedback control applications on a separate systems dynamics level with corresponding methods close to the actuator hardware. This dual representation on an abstract level (for decision making and on the implementation level allows for flexibility and easy adaptation or extension. Results are shown for road vehicle guidance based on three cameras on a gaze control platform.

  1. Motion Intention Analysis-Based Coordinated Control for Amputee-Prosthesis Interaction

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2010-01-01

    Full Text Available To study amputee-prosthesis (AP interaction, a novel reconfigurable biped robot was designed and fabricated. In homogeneous configuration, two identical artificial legs (ALs were used to simulate the symmetrical lower limbs of a healthy person. Linear inverted pendulum model combining with ZMP stability criterion was used to generate the gait trajectories of ALs. To acquire interjoint coordination for healthy gait, rate gyroscopes were mounted on CoGs of thigh and shank of both legs. By employing principal component analysis, the measured angular velocities were processed and the motion synergy was obtained in the final. Then, one of two ALs was replaced by a bionic leg (BL, and the biped robot was changed into heterogeneous configuration to simulate the AP coupling system. To realize symmetrical stable walking, master/slave coordinated control strategy is proposed. According to information acquired by gyroscopes, BL recognized the motion intention of AL and reconstructed its kinematic variables based on interjoint coordination. By employing iterative learning control, gait tracking of BL to AL was archived. Real environment robot walking experiments validated the correctness and effectiveness of the proposed scheme.

  2. Two-Step System Identification and Primitive-Based Motion Planning for Control of Small Unmanned Aerial Vehicles

    Science.gov (United States)

    Grymin, David J.

    This dissertation addresses motion planning, modeling, and feedback control for autonomous vehicle systems. A hierarchical approach for motion planning and control of nonlinear systems operating in obstacle environments is presented. To reduce computation time during the motion planning process, dynamically feasible trajectories are generated in real-time through concatenation of pre-specified motion primitives. The motion planning task is posed as a search over a directed graph, and the applicability of informed graph search techniques is investigated. Specifically, a locally greedy algorithm with effective backtracking ability is developed and compared to weighted A* search. The greedy algorithm shows an advantage with respect to solution cost and computation time when larger motion primitive libraries that do not operate on a regular state lattice are utilized. Linearization of the nonlinear system equations about the motion primitive library results in a hybrid linear time-varying model, and an optimal control algorithm using the l 2-induced norm as the performance measure is applied to ensure that the system tracks the desired trajectory. The ability of the resulting controller to closely track the trajectory obtained from the motion planner, despite various disturbances and uncertainties, is demonstrated through simulation. Additionally, an approach for obtaining dynamically feasible reference trajectories and feedback controllers for a small unmanned aerial vehicle (UAV) based on an aerodynamic model derived from flight tests is presented. The modeling approach utilizes the two step method (TSM) with stepwise multiple regression to determine relevant explanatory terms for the aerodynamic models. Dynamically feasible trajectories are then obtained through the solution of an optimal control problem using pseudospectral optimal control software. Discretetime feedback controllers are then obtained to regulate the vehicle along the desired reference trajectory

  3. A control theory approach to the analysis and synthesis of the experimentally observed motion primitives.

    Science.gov (United States)

    Nori, Francesco; Frezza, Ruggero

    2005-11-01

    Recent experiments on frogs and rats, have led to the hypothesis that sensory-motor systems are organized into a finite number of linearly combinable modules; each module generates a motor command that drives the system to a predefined equilibrium. Surprisingly, in spite of the infiniteness of different movements that can be realized, there seems to be only a handful of these modules. The structure can be thought of as a vocabulary of "elementary control actions". Admissible controls, which in principle belong to an infinite dimensional space, are reduced to the linear vector space spanned by these elementary controls. In the present paper we address some theoretical questions that arise naturally once a similar structure is applied to the control of nonlinear kinematic chains. First of all, we show how to choose the modules so that the system does not loose its capability of generating a "complete" set of movements. Secondly, we realize a "complete" vocabulary with a minimal number of elementary control actions. Subsequently, we show how to modify the control scheme so as to compensate for parametric changes in the system to be controlled. Remarkably, we construct a set of modules with the property of being invariant with respect to the parameters that model the growth of an individual. Robustness against uncertainties is also considered showing how to optimally choose the modules equilibria so as to compensate for errors affecting the system. Finally, the motion primitive paradigm is extended to locomotion and a related formalization of internal (proprioceptive) and external (exteroceptive) variables is given.

  4. Motion and Form Coherence Detection in Autistic Spectrum Disorder: Relationship to Motor Control and 2:4 Digit Ratio

    Science.gov (United States)

    Milne, Elizabeth; White, Sarah; Campbell, Ruth; Swettenham, John; Hansen, Peter; Ramus, Franck

    2006-01-01

    Children with autistic spectrum disorder and controls performed tasks of coherent motion and form detection, and motor control. Additionally, the ratio of the 2nd and 4th digits of these children, which is thought to be an indicator of foetal testosterone, was measured. Children in the experimental group were impaired at tasks of motor control,…

  5. The control of a free-piston engine generator. Part 2: Engine dynamics and piston motion control

    Energy Technology Data Exchange (ETDEWEB)

    Mikalsen, R.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU England (United Kingdom)

    2010-04-15

    Free-piston engines are under investigation by a number of research groups due to potential fuel efficiency and exhaust emissions advantages over conventional technology. The main challenge with such engines is the control of the piston motion, and this has not yet been fully resolved for all types of free-piston engines. This paper builds on the fundamental investigations presented in the accompanying paper and investigates the dynamics of the engine and the feasibility of classical control approaches. The response of the engine to rapid load changes are investigated using decentralised PID, PDF and disturbance feedforward. It is found that the engine is sensitive to rapid load changes but that in constant power applications standard control techniques provide satisfactory performance. The influence of cycle-to-cycle variations in the combustion process are investigated, but not found to be critical for engine operation. (author)

  6. Study on robot motion control for intelligent welding processes based on the laser tracking sensor

    Science.gov (United States)

    Zhang, Bin; Wang, Qian; Tang, Chen; Wang, Ju

    2017-06-01

    A robot motion control method is presented for intelligent welding processes of complex spatial free-form curve seams based on the laser tracking sensor. First, calculate the tip position of the welding torch according to the velocity of the torch and the seam trajectory detected by the sensor. Then, search the optimal pose of the torch under constraints using genetic algorithms. As a result, the intersection point of the weld seam and the laser plane of the sensor is within the detectable range of the sensor. Meanwhile, the angle between the axis of the welding torch and the tangent of the weld seam meets the requirements. The feasibility of the control method is proved by simulation.

  7. Autocorrelated process control: Geometric Brownian Motion approach versus Box-Jenkins approach

    Science.gov (United States)

    Salleh, R. M.; Zawawi, N. I.; Gan, Z. F.; Nor, M. E.

    2018-04-01

    Existing of autocorrelation will bring a significant effect on the performance and accuracy of process control if the problem does not handle carefully. When dealing with autocorrelated process, Box-Jenkins method will be preferred because of the popularity. However, the computation of Box-Jenkins method is too complicated and challenging which cause of time-consuming. Therefore, an alternative method which known as Geometric Brownian Motion (GBM) is introduced to monitor the autocorrelated process. One real case of furnace temperature data is conducted to compare the performance of Box-Jenkins and GBM methods in monitoring autocorrelation process. Both methods give the same results in terms of model accuracy and monitoring process control. Yet, GBM is superior compared to Box-Jenkins method due to its simplicity and practically with shorter computational time.

  8. G-paq: a motion control and data acquisition package for ion beam analysis

    International Nuclear Information System (INIS)

    Spizzirri, P.G.; Den Besten, J.L.; Jamieson, D.N.

    1999-01-01

    The analysis of crystalline materials using nuclear microprobe techniques is now commonplace. Channeling contrast microscopy (CCM) and Rutherford Backscattering (RBS) angular two-dimensional scans, which are used to study defects, strain, surface effects and the presence of impurity atoms in crystalline materials, can benefit from automation through computer control. Important criteria for a computer controlled instrument such as this are: suitable operating system (eg. Microsoft Windows), a graphical user interface (GUI), readily available components, cost effectiveness, ease of use, flexibility and scalability. While there are a number of effective RBS channeling angular scanning solutions in use throughout the microprobe community, few can provide this level of application abstraction. Recent trends in software and hardware development have seen the emergence of desktop/laptop personal computer-based virtual instruments. It has been said that the PC is now the most powerful and cost effective approach to building instruments because they can outperform 'blackbox' solutions in computing power, data transfer rates, memory, data storage, graphics, ease of use and familiarity. Other benefits stem from the availability of commercial-off-the-shelf (COTS) components (hardware) that can often provide complex functionality and third party analysis software that can extend the instrument's use beyond the vendor defined limits. This paper discusses a general purpose, data acquisition and motion control solution, G-Paq, based upon the National Instruments LabVIEW hardware and software development environment. Locally developed, this solution uses a minimum of customised components, is compatible with the principals of Good Laboratory Practice (GLP), is easy to use, has a graphical user interface and is flexible. While it has been developed for nuclear microprobe based channeling contrast microscopy using a specimen stage goniometer, its application to general motion control

  9. Emulating a robotic manipulator arm with an hybrid motion-control system

    International Nuclear Information System (INIS)

    Aragón-González, G; León-Galicia, A; Noriega-Hernández, M; Salazar-Hueta, A

    2015-01-01

    A motion control system with four and 1/2 degrees of freedom, designed to move small objects within a 0.25 m3 space, parallel to a horizontal table, with high speed and performance similar to a robotic manipulator arm was built. The machine employs several actuators and control devices. Its main characteristic is to incorporate a servomotor, steeper motors, electromechanical and fluid power actuators and diverse control resources. A group of actuators arranged on a spherical coordinates system is attached to the servomotor platform. A linear pneumatic actuator with an angular grip provides the radial extension and load clamping capacity. Seven inductive proximity sensors and one encoder provide feedback, for operating the actuators under closed loop conditions. Communication between the sensors and control devices is organized by a PLC. A touch screen allows governing the system remotely, easily and interactively, without knowing the specific programming language of each control component. The graphic environment on the touch screen guides the user to design and store control programs, establishing coordinated automatic routines for moving objects in space, simulation and implementation of industrial positioning or machining processes

  10. Space Weather Influence on Relative Motion Control using the Touchless Electrostatic Tractor

    Science.gov (United States)

    Hogan, Erik A.; Schaub, Hanspeter

    2016-09-01

    With recent interest in the use of electrostatic forces for contactless tugging and attitude control of noncooperative objects for orbital servicing and active debris mitigation, the need for a method of remote charge control arises. In this paper, the use of a directed electron beam for remote charge control is considered in conjunction with the relative motion control. A tug vehicle emits an electron beam onto a deputy object, charging it negatively. At the same time, the tug is charged positively due to beam emission, resulting in an attractive electrostatic force. The relative position feedback control between the tug and the passive debris object is studied subject to the charging being created through an electron beam. Employing the nominal variations of the GEO space weather conditions across longitude slots, two electrostatic tugging strategies are considered. First, the electron beam current is adjusted throughout the orbit in order to maximize this resulting electrostatic force. This open-loop control strategy compensates for changes in the nominally expected local space weather environment in the GEO region to adjust for fluctuations in the local plasma return currents. Second, the performance impact of using a fixed electron beam current on the electrostatic tractor is studied if the same natural space weather variations are assumed. The fixed electron beam current shows a minor performance penalty (<5 %) while providing a much simpler implementation that does not require any knowledge of local space weather conditions.

  11. Neck motion, motor control, pain and disability: A longitudinal study of associations in neck pain patients in physiotherapy treatment.

    Science.gov (United States)

    Meisingset, Ingebrigt; Stensdotter, Ann-Katrin; Woodhouse, Astrid; Vasseljen, Ottar

    2016-04-01

    Neck pain is associated with several alterations in neck motion and motor control, but most of the findings are based on cross-sectional studies. The aim of this study was to investigate associations between changes in neck motion and motor control, and changes in neck pain and disability in physiotherapy patients during a course of treatment. Prospective cohort study. Subjects with non-specific neck pain (n = 71) participated in this study. Neck flexibility, joint position error (JPE), head steadiness, trajectory movement control and postural sway were recorded before commencement of physiotherapy (baseline), at 2 weeks, and at 2 months. Numerical Rating Scale and Neck Disability Index were used to measure neck pain and disability at the day of testing. To analyze within subjects effects in neck motion and motor control, neck pain, and disability over time we used fixed effects linear regression analysis. Changes in neck motion and motor control occurred primarily within 2 weeks. Reduction in neck pain was associated with increased cervical range of motion in flexion-/extension and increased postural sway when standing with eyes open. Decreased neck disability was associated with some variables for neck flexibility and trajectory movement control. Cervical range of motion in flexion-/extension was the only variable associated with changes in both neck pain and neck disability. This study shows that few of the variables for neck motion and motor control were associated with changes neck pain and disability over a course of 2 months with physiotherapy treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A Novel Pitch Control System of a Large Wind Turbine Using Two-Degree-of-Freedom Motion Control with Feedback Linearization Control

    Directory of Open Access Journals (Sweden)

    Ching-Sung Wang

    2016-09-01

    Full Text Available Pitch Control plays a significant role for a large wind turbine. This study investigates a novel robust hydraulic pitch control system of a large wind turbine. The novel hydraulic pitch control system is driven by a novel high efficiency and high response hydraulic servo system. The pitch controller, designed by two degree-of-freedom (2-DOF motion control with feedback linearization, is developed to enhance the controllability and stability of the pitch control system. Furthermore, the full-scale testbed of the hydraulic pitch control system of a large wind turbine is developed for practically experimental verification. Besides, the wind turbine simulation software FAST is used to analyze the motion of the blade which results are given to the testbed as the disturbance load command. The 2-DOF pitch controller contains a feedforward controller with feedback linearization theory to overcome the nonlinearities of the system and a feedback controller to improve the system robustness for achieving the disturbance rejection. Consequently, the novel hydraulic pitch control system shows excellent path tracking performance in the experiments. Moreover, the robustness test with a simulated disturbance load generated by FAST is performed to validate the reliability of the proposed pitch control system.

  13. Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions - Effect of Velocity

    Science.gov (United States)

    Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

    2013-01-01

    Background Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements. Methods The criterion validity of accuracy was established under controlled conditions using an instrumented Gimbal table. AHRS modules were carefully attached to the center plate of the Gimbal table and put through experimental static and dynamic conditions. Static and absolute accuracy was assessed by comparing the AHRS orientation measurement to those obtained using an optical gold standard. Relative accuracy was assessed by measuring the variation in relative orientation between modules during trials. Findings Evaluated AHRS systems demonstrated good absolute static accuracy (mean error < 0.5o) and clinically acceptable absolute accuracy under condition of slow motions (mean error between 0.5o and 3.1o). In slow motions, relative accuracy varied from 2o to 7o depending on the type of AHRS and the type of rotation. Absolute and relative accuracy were significantly affected (p<0.05) by velocity during sustained motions. The extent of that effect varied across AHRS. Interpretation Absolute and relative accuracy of AHRS are affected by environmental magnetic perturbations and conditions of motions. Relative accuracy of AHRS is mostly affected by the ability of all modules to locate the same global reference coordinate system at all time. Conclusions Existing AHRS systems can be considered for use in clinical biomechanics under constrained conditions of use. While their individual capacity to track absolute motion is relatively consistent, the use of multiple AHRS modules to compute relative motion between rigid bodies needs to be optimized according to

  14. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    OpenAIRE

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, ...

  15. Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

    Directory of Open Access Journals (Sweden)

    Xingjian Wang

    2017-10-01

    Full Text Available Moving towards the more electric aircraft (MEA, a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA into primary flight control. In the hybrid actuation system (HAS, an electro-hydraulic servo actuator (EHSA and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA.

  16. Linear Extended State Observer-Based Motion Synchronization Control for Hybrid Actuation System of More Electric Aircraft

    Science.gov (United States)

    Liao, Rui; Shi, Cun; Wang, Shaoping

    2017-01-01

    Moving towards the more electric aircraft (MEA), a hybrid actuator configuration provides an opportunity to introduce electromechanical actuator (EMA) into primary flight control. In the hybrid actuation system (HAS), an electro-hydraulic servo actuator (EHSA) and an EMA operate on the same control surface. In order to solve force fighting problem in HAS, this paper proposes a novel linear extended state observer (LESO)-based motion synchronization control method. To cope with the problem of unavailability of the state signals required by the motion synchronization controller, LESO is designed for EHSA and EMA to observe the state variables. Based on the observed states of LESO, motion synchronization controllers could enable EHSA and EMA to simultaneously track the desired motion trajectories. Additionally, nonlinearities, uncertainties and unknown disturbances as well as the coupling term between EHSA and EMA can be estimated and compensated by using the extended state of the proposed LESO. Finally, comparative simulation results indicate that the proposed LESO-based motion synchronization controller could reduce significant force fighting between EHSA and EMA. PMID:29068392

  17. Investigation and Development of Control Laws for the NASA Langley Research Center Cockpit Motion Facility

    Science.gov (United States)

    Coon, Craig R.; Cardullo, Frank M.; Zaychik, Kirill B.

    2014-01-01

    The ability to develop highly advanced simulators is a critical need that has the ability to significantly impact the aerospace industry. The aerospace industry is advancing at an ever increasing pace and flight simulators must match this development with ever increasing urgency. In order to address both current problems and potential advancements with flight simulator techniques, several aspects of current control law technology of the National Aeronautics and Space Administration (NASA) Langley Research Center's Cockpit Motion Facility (CMF) motion base simulator were examined. Preliminary investigation of linear models based upon hardware data were examined to ensure that the most accurate models are used. This research identified both system improvements in the bandwidth and more reliable linear models. Advancements in the compensator design were developed and verified through multiple techniques. The position error rate feedback, the acceleration feedback and the force feedback were all analyzed in the heave direction using the nonlinear model of the hardware. Improvements were made using the position error rate feedback technique. The acceleration feedback compensator also provided noteworthy improvement, while attempts at implementing a force feedback compensator proved unsuccessful.

  18. Control of trunk motion following sudden stop perturbations during cart pushing.

    Science.gov (United States)

    Lee, Yun-Ju; Hoozemans, Marco J M; van Dieën, Jaap H

    2011-01-04

    External perturbations during pushing tasks have been suggested to be a risk factor for low-back symptoms. An experiment was designed to investigate whether self-induced and externally induced sudden stops while pushing a high inertia cart influence trunk motions, and how flexor and extensor muscles counteract these perturbations. Twelve healthy male participants pushed a 200 kg cart at shoulder height and hip height. Pushing while walking was compared to situations in which participants had to stop the cart suddenly (self-induced stop) or in which the wheels of the cart were unexpectedly blocked (externally induced stop). For the perturbed conditions, the peak values and the maximum changes from the reference condition (pushing while walking) of the external moment at L5/S1, trunk inclination and electromyographic amplitudes of trunk muscles were determined. In the self-induced stop, a voluntary trunk extension occurred. Initial responses in both stops consisted of flexor and extensor muscle cocontraction. In self-induced stops this was followed by sustained extensor activity. In the externally induced stops, an external extension moment caused a decrease in trunk inclination. The opposite directions of the internal moment and trunk motion in the externally induced stop while pushing at shoulder height may indicate insufficient active control of trunk posture. Consequently, sudden blocking of the wheels in pushing at shoulder height may put the low back at risk of mechanical injury. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Procedural Audio in Computer Games Using Motion Controllers: An Evaluation on the Effect and Perception

    Directory of Open Access Journals (Sweden)

    Niels Böttcher

    2013-01-01

    Full Text Available A study has been conducted into whether the use of procedural audio affects players in computer games using motion controllers. It was investigated whether or not (1 players perceive a difference between detailed and interactive procedural audio and prerecorded audio, (2 the use of procedural audio affects their motor-behavior, and (3 procedural audio affects their perception of control. Three experimental surveys were devised, two consisting of game sessions and the third consisting of watching videos of gameplay. A skiing game controlled by a Nintendo Wii balance board and a sword-fighting game controlled by a Wii remote were implemented with two versions of sound, one sample based and the other procedural based. The procedural models were designed using a perceptual approach and by alternative combinations of well-known synthesis techniques. The experimental results showed that, when being actively involved in playing or purely observing a video recording of a game, the majority of participants did not notice any difference in sound. Additionally, it was not possible to show that the use of procedural audio caused any consistent change in the motor behavior. In the skiing experiment, a portion of players perceived the control of the procedural version as being more sensitive.

  20. Virtual reality body motion induced navigational controllers and their effects on simulator sickness and pathfinding.

    Science.gov (United States)

    Aldaba, Cassandra N; White, Paul J; Byagowi, Ahmad; Moussavi, Zahra

    2017-07-01

    Virtual reality (VR) navigation is usually constrained by plausible simulator sickness (SS) and intuitive user interaction. The paper reports on the use of four different degrees of body motion induced navigational VR controllers, a TiltChair, omni-directional treadmill, a manual wheelchair joystick (VRNChair), and a joystick in relation to a participant's SS occurrence and a controller's intuitive utilization. Twenty young adult participants utilized all controllers to navigate through the same VR task environment in separate sessions. Throughout the sessions, SS occurrence was measured from a severity score by a standard SS questionnaire and from body sway by a center of pressure path length with eyes opened and closed. SS occurrence did not significantly differ among the controllers. However, time spent in VR significantly contributed to SS occurrence; hence, a few breaks to minimize SS should be interjected throughout a VR task. For all task trials, we recorded the participant's travel trajectories to investigate each controller's intuitive utilization from a computed traversed distance. Shorter traversed distances indicated that participants intuitively utilized the TiltChair with a slower speed; while longer traversed distances indicated participants struggled to utilize the omni-directional treadmill with a unnaturalistic stimulation of gait. Therefore, VR navigation should use technologies best suited for the intended age group that minimizes SS, and produces intuitive interactions for the participants.

  1. Control of a Virtual Vehicle Influences Postural Activity and Motion Sickness

    Science.gov (United States)

    Dong, Xiao; Yoshida, Ken; Stoffregen, Thomas A.

    2011-01-01

    Everyday experience suggests that drivers are less susceptible to motion sickness than passengers. In the context of inertial motion (i.e., physical displacement), this effect has been confirmed in laboratory research using whole body motion devices. We asked whether a similar effect would occur in the context of simulated vehicles in a visual…

  2. Design and control of three fingers motion for dexterous assembly of ...

    African Journals Online (AJOL)

    In this paper, the authors describe and demonstrate how a three fingered gripper can be designed and simulated to provide both gross motion and fine motion to the fingers. ... This mimicry is required to design the correct motions and tactile forces necessary to handle delicate and non delicate engineering components.

  3. Evaluation of the Leap Motion Controller during the performance of visually-guided upper limb movements.

    Science.gov (United States)

    Niechwiej-Szwedo, Ewa; Gonzalez, David; Nouredanesh, Mina; Tung, James

    2018-01-01

    Kinematic analysis of upper limb reaching provides insight into the central nervous system control of movements. Until recently, kinematic examination of motor control has been limited to studies conducted in traditional research laboratories because motion capture equipment used for data collection is not easily portable and expensive. A recently developed markerless system, the Leap Motion Controller (LMC), is a portable and inexpensive tracking device that allows recording of 3D hand and finger position. The main goal of this study was to assess the concurrent reliability and validity of the LMC as compared to the Optotrak, a criterion-standard motion capture system, for measures of temporal accuracy and peak velocity during the performance of upper limb, visually-guided movements. In experiment 1, 14 participants executed aiming movements to visual targets presented on a computer monitor. Bland-Altman analysis was conducted to assess the validity and limits of agreement for measures of temporal accuracy (movement time, duration of deceleration interval), peak velocity, and spatial accuracy (endpoint accuracy). In addition, a one-sample t-test was used to test the hypothesis that the error difference between measures obtained from Optotrak and LMC is zero. In experiment 2, 15 participants performed a Fitts' type aiming task in order to assess whether the LMC is capable of assessing a well-known speed-accuracy trade-off relationship. Experiment 3 assessed the temporal coordination pattern during the performance of a sequence consisting of a reaching, grasping, and placement task in 15 participants. Results from the t-test showed that the error difference in temporal measures was significantly different from zero. Based on the results from the 3 experiments, the average temporal error in movement time was 40±44 ms, and the error in peak velocity was 0.024±0.103 m/s. The limits of agreement between the LMC and Optotrak for spatial accuracy measures ranged between

  4. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot). PMID:25140875

  5. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  6. Quality control of structural MRI images applied using FreeSurfer - a hands-on workflow to rate motion artifacts

    Directory of Open Access Journals (Sweden)

    Lea Luise Backhausen

    2016-12-01

    Full Text Available In structural magnetic resonance imaging motion artifacts are common, especially when not scanning healthy young adults. It has been shown that motion affects the analysis with automated image-processing techniques (e.g. FreeSurfer. This can bias results. Several developmental and adult studies have found reduced volume and thickness of gray matter due to motion artifacts. Thus, quality control is necessary in order to ensure an acceptable level of quality and to define exclusion criteria of images (i.e. determine participants with most severe artifacts. However, information about the quality control workflow and image exclusion procedure is largely lacking in the current literature and the existing rating systems differ. Here we propose a stringent workflow of quality control steps during and after acquisition of T1-weighted images, which enables researchers dealing with populations that are typically affected by motion artifacts to enhance data quality and maximize sample sizes. As an underlying aim we established a thorough quality control rating system for T1-weighted images and applied it to the analysis of developmental clinical data using the automated processing pipeline FreeSurfer. This hands-on workflow and quality control rating system will aid researchers in minimizing motion artifacts in the final data set, and therefore enhance the quality of structural magnetic resonance imaging studies.

  7. Redox control of rotary motions in ferrocene-based elemental ball bearings.

    Science.gov (United States)

    Iordache, Adriana; Oltean, Mircea; Milet, Anne; Thomas, Fabrice; Baptiste, Benoît; Saint-Aman, Eric; Bucher, Christophe

    2012-02-08

    Rotational motions of ferrocene-based carousels have been achieved by electron transfer centered on π-dimerizable 4,4'-bipyridinium substituents introduced on both cyclopentadienyl rings through covalent linkers of different size, geometry, and flexibility. Detailed spectroscopic, electrochemical, and theoretical analyses demonstrate that rigid and fully conjugated linkers allow the quantitative formation of intramolecular π-dimers resulting from optimized orbital overlaps within the HOMO of the electrochemically generated bis-radical species. The tetra-cationic "charge-repelled" conformers, the self-assembled π-dimers, and their electron triggered interconversions have been investigated by UV-vis, NMR, and ESR spectroscopy, electrochemistry, X-ray diffraction analysis, and theoretical calculations. These studies support the conclusion that the rotation of both cyclopentadienyl rings in ferrocene can be controlled electrochemically using noncovalent reversible interactions arising from π-radical coupling processes.

  8. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.; Chuvilin, Andrey; Lopatin, Sergei; Kosel, Jü rgen

    2016-01-01

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  9. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories

    KAUST Repository

    Ivanov, Yurii P.

    2016-05-03

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. © 2016 American Chemical Society.

  10. Chaos control of Hastings–Powell model by combining chaotic motions

    International Nuclear Information System (INIS)

    Danca, Marius-F.; Chattopadhyay, Joydev

    2016-01-01

    In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings–Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: “losing + losing = winning.” If “loosing” is replaced with “chaos” and, “winning” with “order” (as the opposite to “chaos”), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write “chaos + chaos = regular.” Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

  11. Chaos control of Hastings–Powell model by combining chaotic motions

    Energy Technology Data Exchange (ETDEWEB)

    Danca, Marius-F., E-mail: danca@rist.ro [Romanian Institute of Science and Technology, 400487 Cluj-Napoca (Romania); Chattopadhyay, Joydev, E-mail: joydev@isical.ac.in [Agricultural and Ecological Research Unit Indian Statistical Institute, 203, B. T. Road, Kolkata 700 108 (India)

    2016-04-15

    In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings–Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: “losing + losing = winning.” If “loosing” is replaced with “chaos” and, “winning” with “order” (as the opposite to “chaos”), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write “chaos + chaos = regular.” Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

  12. Motion behaviour of magneto-sensitive elastomers controlled by an external magnetic field for sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Volkova, T.I., E-mail: tatiana.volkova@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Böhm, V., E-mail: valter.boehm@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Kaufhold, T., E-mail: tobias.kaufhold@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Popp, J., E-mail: jana.popp@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Becker, F., E-mail: felix.becker@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany); Borin, D.Yu., E-mail: dmitry.borin@tu-dresden.de [Technische Universität Dresden, Magnetofluiddynamics, Measuring and Automation Technology, D-01062 Dresden (Germany); Stepanov, G.V., E-mail: gstepanov@mail.ru [State Institute of Chemistry and Technology of Organoelement Compounds, 105118 Moscow (Russian Federation); Zimmermann, K., E-mail: klaus.zimmermann@tu-ilmenau.de [Technische Universität Ilmenau, Faculty of Mechanical Engineering, Technical Mechanics Group, D-98693 Ilmenau (Germany)

    2017-06-01

    The development of sensor systems with a complex adaptive regulation of the operating sensitivity and behaviour is an actual scientific and technical challenge. Smart materials like magneto-sensitive elastomers (MSE) are seen as one potential solution for this problem, since their mechanical properties may be controlled by external magnetic fields. The present paper deals with the investigation of elastic and damping properties of MSE containing magnetically soft particles under the influence of a uniform magnetic field. Based on the measurement of the first eigenfrequency of free bending vibrations of a fixed beam, the effective Young's modulus is evaluated theoretically and also numerically using Finite Element Method. It is shown that this parameter, as well as the first eigenfrequency of the beam, increases monotonically with the magnitude of the applied magnetic field. The results are aimed to develop an acceleration sensor with adaptive magnetically controllable sensitivity range for the detection of external mechanical stimuli of the environment. - Highlights: • The motion behaviour of magneto-sensitive elastomers (MSE) with magnetically soft particles is investigated. • The first eigenfrequency of free bending vibrations of an MSE beam can be controlled by a uniform magnetic field. • Based on the experimental results, the effective Young's modulus of the system is evaluated theoretically and numerically. • The Young's modulus increases monotonically with the magnitude of the applied magnetic field. • The controlled mechanical compliance of MSE may be used for development of sensor systems with adaptive sensitivity range.

  13. Chaos control of Hastings-Powell model by combining chaotic motions.

    Science.gov (United States)

    Danca, Marius-F; Chattopadhyay, Joydev

    2016-04-01

    In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings-Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: "losing + losing = winning." If "loosing" is replaced with "chaos" and, "winning" with "order" (as the opposite to "chaos"), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write "chaos + chaos = regular." Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

  14. Evaluation of a portable markerless finger position capture device: accuracy of the Leap Motion controller in healthy adults.

    Science.gov (United States)

    Tung, James Y; Lulic, Tea; Gonzalez, Dave A; Tran, Johnathan; Dickerson, Clark R; Roy, Eric A

    2015-05-01

    Although motion analysis is frequently employed in upper limb motor assessment (e.g. visually-guided reaching), they are resource-intensive and limited to laboratory settings. This study evaluated the reliability and accuracy of a new markerless motion capture device, the Leap Motion controller, to measure finger position. Testing conditions that influence reliability and agreement between the Leap and a research-grade motion capture system were examined. Nine healthy young adults pointed to 15 targets on a computer screen under two conditions: (1) touching the target (touch) and (2) 4 cm away from the target (no-touch). Leap data was compared to an Optotrak marker attached to the index finger. Across all trials, root mean square (RMS) error of the Leap system was 17.30  ±  9.56 mm (mean ± SD), sampled at 65.47  ±  21.53 Hz. The % viable trials and mean sampling rate were significantly lower in the touch condition (44% versus 64%, p motion capture systems, the Leap Motion controller is sufficiently reliable for measuring motor performance in pointing tasks that do not require high positional accuracy (e.g. reaction time, Fitt's, trails, bimanual coordination).

  15. Chaos and its control in the pitch motion of an asymmetric magnetic spacecraft in polar elliptic orbit

    Energy Technology Data Exchange (ETDEWEB)

    Inarrea, Manuel [Universidad de La Rioja, Area de Fisica Aplicada, 26006 Logrono (Spain)], E-mail: manuel.inarrea@unirioja.es

    2009-05-30

    We study the pitch attitude dynamics of an asymmetric magnetic spacecraft in a polar almost circular orbit under the influence of a gravity gradient torque. The spacecraft is perturbed by the small eccentricity of the elliptic orbit and by a small magnetic torque generated by the interaction between the Earth's magnetic field and the magnetic moment of the spacecraft. Under both perturbations, we show that the pitch motion exhibits heteroclinic chaotic behavior by means of the Melnikov method. Numerical methods applied to simulations of the pitch motion also confirm the chaotic character of the spacecraft attitude dynamics. Finally, a linear time-delay feedback method for controlling chaos is applied to the governing equations of the spacecraft pitch motion in order to remove the chaotic character of initially irregular attitude motions and transform them into periodic ones.

  16. Chaos and its control in the pitch motion of an asymmetric magnetic spacecraft in polar elliptic orbit

    International Nuclear Information System (INIS)

    Inarrea, Manuel

    2009-01-01

    We study the pitch attitude dynamics of an asymmetric magnetic spacecraft in a polar almost circular orbit under the influence of a gravity gradient torque. The spacecraft is perturbed by the small eccentricity of the elliptic orbit and by a small magnetic torque generated by the interaction between the Earth's magnetic field and the magnetic moment of the spacecraft. Under both perturbations, we show that the pitch motion exhibits heteroclinic chaotic behavior by means of the Melnikov method. Numerical methods applied to simulations of the pitch motion also confirm the chaotic character of the spacecraft attitude dynamics. Finally, a linear time-delay feedback method for controlling chaos is applied to the governing equations of the spacecraft pitch motion in order to remove the chaotic character of initially irregular attitude motions and transform them into periodic ones.

  17. Initial experience with active breathing control of liver motion during ventilation

    International Nuclear Information System (INIS)

    Robertson, John M.; Sharpe, Michael B.; Jaffray, David A.; Wong, John W.

    1997-01-01

    Purpose: Recent evidence has shown that some patients with hepatic tumors can be safely irradiated to a dose well over twice the whole liver tolerance dose if portions of normal liver are spared. Correction during treatment planning for the ventilatory motion of the liver can add a large volume of normal liver to the planning target volume. Any reduction in ventilatory motion has the potential to allow a higher dose of radiation to be given safely. Active Breathing Control (ABC) can be used to temporarily stop the airflow to a patient, thus immobilizing the liver, at any part of a patient's ventilatory cycle. ABC during helical CT scanning can be used to study the full three dimensional motion of the liver and other abdominal organs during ventilation. Ultimately, if the use of ABC is found to be clinically feasible, tolerable for patients, and, most importantly, reproducible over time, then ABC may be used during radiation treatment. Materials and Methods: An ABC apparatus was constructed using a flow monitor and scissor valves on both the inhalation and exhalation paths to the patient. The patient breathed through either a mouthpiece or facemask during the procedure. The ventilatory cycle was displayed in real time. When a stable breathing pattern was observed, the ABC was activated at a specific lung volume, closing both scissors valves, and preventing ventilation. The length of time for comfortable activation of the ABC machine for the individual patient was determined during a teaching and practice period prior to CT scanning. Helical CT scans (slice thickness 0.5 cm) to assess the potential benefit of immobilizing breathing were obtained for normal breathing, end-inspiration and end-expiration. The reproducibility of ABC over time was assessed by repeating the end-inspiration scan both immediately and one week later. The contours of the liver and kidneys were entered for each study. Results: Five patients have undergone ABC study of the abdomen. End

  18. Development of an assist controller with robot suit HAL for hemiplegic patients using motion data on the unaffected side.

    Science.gov (United States)

    Kawamoto, Hiroaki; Kandone, Hideki; Sakurai, Takeru; Ariyasu, Ryohei; Ueno, Yukiko; Eguchi, Kiyoshi; Sankai, Yoshiyuki

    2014-01-01

    Among several characteristics seen in gait of hemiplegic patients after stroke, symmetry is known to be an indicator of the degree of impairment of walking ability. This paper proposes a control method for a wearable type lower limb motion assist robot to realize spontaneous symmetric gait for these individuals. This control method stores the motion of the unaffected limb during swing and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. This method is implemented on the robot suit HAL (Hybrid Assistive Limbs). Clinical tests were conducted in order to assess the feasibility of the control method. Our case study involved participation of one chronic stroke patient who was not able to flex his right knee. As a result, the walking support for hemiplegic leg provided by the HAL improved the subject's gait symmetry. The feasibility study showed promising basis for the future clinical study.

  19. Efficacy of early controlled motion of the ankle compared with no motion after non-operative treatment of an acute Achilles tendon rupture

    DEFF Research Database (Denmark)

    Barfod, Kristoffer Weisskirchner; Hansen, Maria Swennergren; Hølmich, Per

    2016-01-01

    controlled motion of the ankle in weeks 3-8 after rupture. The control group is immobilized. In total, 130 patients will be included from one big orthopedic center over a period of 2½ years. The primary outcome is the patient-reported Achilles tendon Total Rupture Score evaluated at 12 months post...... affects functional and patient-reported outcomes. METHODS/DESIGN: The study is performed as a blinded, randomized, controlled trial with patients allocated in a 1:1 ratio to one of two parallel groups. Patients aged from 18 to 70 years are eligible for inclusion. The intervention group performs early...... of acute Achilles tendon rupture in a randomized setup. The study uses the patient-reported outcome measure, the Achilles tendon Total Rupture Score, as the primary endpoint, as it is believed to be the best surrogate measure for the tendon's actual capability to function in everyday life. TRIAL...

  20. Vehicle lateral motion regulation under unreliable communication links based on robust H∞ output-feedback control schema

    Science.gov (United States)

    Li, Cong; Jing, Hui; Wang, Rongrong; Chen, Nan

    2018-05-01

    This paper presents a robust control schema for vehicle lateral motion regulation under unreliable communication links via controller area network (CAN). The communication links between the system plant and the controller are assumed to be imperfect and therefore the data packet dropouts occur frequently. The paper takes the form of parallel distributed compensation and treats the dropouts as random binary numbers that form Bernoulli distribution. Both of the tire cornering stiffness uncertainty and external disturbances are considered to enhance the robustness of the controller. In addition, a robust H∞ static output-feedback control approach is proposed to realize the lateral motion control with relative low cost sensors. The stochastic stability of the closed-loop system and conservation of the guaranteed H∞ performance are investigated. Simulation results based on CarSim platform using a high-fidelity and full-car model verify the effectiveness of the proposed control approach.

  1. Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator.

    Science.gov (United States)

    Kim, Sung Hoon; Shin, Kyoosik; Hashi, Shuichiro; Ishiyama, Kazushi

    2012-09-01

    This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities.

  2. Magnetic fish-robot based on multi-motion control of a flexible magnetic actuator

    International Nuclear Information System (INIS)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi; Shin, Kyoosik

    2012-01-01

    This paper presents a biologically inspired fish-robot driven by a single flexible magnetic actuator with a rotating magnetic field in a three-axis Helmholtz coil. Generally, magnetic fish-robots are powered by alternating and gradient magnetic fields, which provide a single motion such as bending the fish-robot's fins. On the other hand, a flexible magnetic actuator driven by an external rotating magnetic field can create several gaits such as the bending vibration, the twisting vibration, and their combination. Most magnetic fish-like micro-robots do not have pectoral fins on the side and are simply propelled by the tail fin. The proposed robot can swim and perform a variety of maneuvers with the addition of pectoral fins and control of the magnetic torque direction. In this paper, we find that the robot's dynamic actuation correlates with the magnetic actuator and the rotating magnetic field. The proposed robot is also equipped with new features, such as a total of six degrees of freedom, a new control method that stabilizes posture, three-dimensional swimming, a new velocity control, and new turning abilities. (paper)

  3. Control Motion Approach of a Lower Limb Orthosis to Reduce Energy Consumption

    Directory of Open Access Journals (Sweden)

    Daniel Sanz-Merodio

    2012-12-01

    Full Text Available By analysing the dynamic principles of the human gait, an economic gait-control analysis is performed, and passive elements are included to increase the energy efficiency in the motion control of active orthoses. Traditional orthoses use position patterns from the clinical gait analyses (CGAs of healthy people, which are then de-normalized and adjusted to each user. These orthoses maintain a very rigid gait, and their energy cost is very high, reducing the autonomy of the user. First, to take advantage of the inherent dynamics of the legs, a state machine pattern with different gains in each state is applied to reduce the actuator energy consumption. Next, different passive elements, such as springs and brakes in the joints, are analysed to further reduce energy consumption. After an off-line parameter optimization and a heuristic improvement with genetic algorithms, a reduction in energy consumption of 16.8% is obtained by applying a state machine control pattern, and a reduction of 18.9% is obtained by using passive elements. Finally, by combining both strategies, a more natural gait is obtained, and energy consumption is reduced by 24.6% compared with a pure CGA pattern.

  4. A piloted evaluation of an oblique-wing research aircraft motion simulation with decoupling control laws

    Science.gov (United States)

    Kempel, Robert W.; Mcneill, Walter E.; Gilyard, Glenn B.; Maine, Trindel A.

    1988-01-01

    The NASA Ames Research Center developed an oblique-wing research plane from NASA's digital fly-by-wire airplane. Oblique-wing airplanes show large cross-coupling in control and dynamic behavior which is not present on conventional symmetric airplanes and must be compensated for to obtain acceptable handling qualities. The large vertical motion simulator at NASA Ames-Moffett was used in the piloted evaluation of a proposed flight control system designed to provide decoupled handling qualities. Five discrete flight conditions were evaluated ranging from low altitude subsonic Mach numbers to moderate altitude supersonic Mach numbers. The flight control system was effective in generally decoupling the airplane. However, all participating pilots objected to the high levels of lateral acceleration encountered in pitch maneuvers. In addition, the pilots were more critical of left turns (in the direction of the trailing wingtip when skewed) than they were of right turns due to the tendency to be rolled into the left turns and out of the right turns. Asymmetric side force as a function of angle of attack was the primary cause of lateral acceleration in pitch. Along with the lateral acceleration in pitch, variation of rolling and yawing moments as functions of angle of attack caused the tendency to roll into left turns and out of right turns.

  5. Auricular Acupressure for Managing Postoperative Pain and Knee Motion in Patients with Total Knee Replacement: A Randomized Sham Control Study

    Directory of Open Access Journals (Sweden)

    Ling-hua Chang

    2012-01-01

    Full Text Available Background. Postoperative pain management remains a significant challenge for all healthcare providers. A randomized controlled trial was conducted to examine the adjuvant effects of auricular acupressure on relieving postoperative pain and improving the passive range of motion in patients with total knee replacement (TKR. Method. Sixty-two patients who had undergone a TKR were randomly assigned to the acupressure group and the sham control group. The intervention was delivered three times a day for 3 days. A visual analog scale (VAS and the Short-Form McGill Pain Questionnaire were used to assess pain intensity. Pain medication consumption was recorded, and the knee motion was measured using a goniometer. Results. The patients experienced a moderately severe level of pain postoperatively (VAS 58.66 ± 20.35 while being on the routine PCA. No differences were found in pain scores between the groups at all points. However, analgesic drug usage in the acupressure group patients was significantly lower than in the sham control group (<0.05, controlling for BMI, age, and pain score. On the 3rd day after surgery, the passive knee motion in the acupressure group patients was significantly better than in the sham control group patients (<0.05, controlling for BMI. Conclusion. The application of auricular acupressure at specific therapeutic points significantly reduces the opioid analgesia requirement and improves the knee motion in patients with TKR.

  6. Assessment of Relationships Between Joint Motion Quality and Postural Control in Patients With Chronic Ankle Joint Instability.

    Science.gov (United States)

    Bączkowicz, Dawid; Falkowski, Krzysztof; Majorczyk, Edyta

    2017-08-01

    Study Design Controlled laboratory study, cross-sectional. Background Lateral ankle sprains are among the most common injuries encountered during athletic participation. Following the initial injury, there is an alarmingly high risk of reinjury and development of chronic ankle instability (CAI), which is dependent on a combination of factors, including sensorimotor deficits and changes in the biomechanical environment of the ankle joint. Objective To evaluate CAI-related disturbances in arthrokinematic motion quality and postural control and the relationships between them. Methods Sixty-three male subjects (31 with CAI and 32 healthy controls) were enrolled in the study. For arthrokinematic motion quality analysis, the vibroarthrographic signals were collected during ankle flexion/extension motion using an acceleration sensor and described by variability (variance of mean squares [VMS]), amplitude (mean of 4 maximal and 4 minimal values [R4]), and frequency (vibroarthrographic signal bands of 50 to 250 Hz [P1] and 250 to 450 Hz [P2]) parameters. Using the Biodex Balance System, single-leg dynamic balance was measured by overall, anteroposterior, and mediolateral stability indices. Results Values of vibroarthrographic parameters (VMS, R4, P1 and P2) were significantly higher in the CAI group than those in the control group (Pankle arthrokinematic motion and postural control were present. Therefore, physical therapy interventions focused on improving ankle neuromuscular control and arthrokinematic function are necessary in CAI patient care. J Orthop Sports Phys Ther 2017;47(8):570-577. Epub 4 Nov 2016. doi:10.2519/jospt.2017.6836.

  7. Hand interception of occluded motion in humans: a test of model-based vs. on-line control.

    Science.gov (United States)

    La Scaleia, Barbara; Zago, Myrka; Lacquaniti, Francesco

    2015-09-01

    Two control schemes have been hypothesized for the manual interception of fast visual targets. In the model-free on-line control, extrapolation of target motion is based on continuous visual information, without resorting to physical models. In the model-based control, instead, a prior model of target motion predicts the future spatiotemporal trajectory. To distinguish between the two hypotheses in the case of projectile motion, we asked participants to hit a ball that rolled down an incline at 0.2 g and then fell in air at 1 g along a parabola. By varying starting position, ball velocity and trajectory differed between trials. Motion on the incline was always visible, whereas parabolic motion was either visible or occluded. We found that participants were equally successful at hitting the falling ball in both visible and occluded conditions. Moreover, in different trials the intersection points were distributed along the parabolic trajectories of the ball, indicating that subjects were able to extrapolate an extended segment of the target trajectory. Remarkably, this trend was observed even at the very first repetition of movements. These results are consistent with the hypothesis of model-based control, but not with on-line control. Indeed, ball path and speed during the occlusion could not be extrapolated solely from the kinematic information obtained during the preceding visible phase. The only way to extrapolate ball motion correctly during the occlusion was to assume that the ball would fall under gravity and air drag when hidden from view. Such an assumption had to be derived from prior experience. Copyright © 2015 the American Physiological Society.

  8. Modeling the angular motion dynamics of spacecraft with a magnetic attitude control system based on experimental studies and dynamic similarity

    Science.gov (United States)

    Kulkov, V. M.; Medvedskii, A. L.; Terentyev, V. V.; Firsyuk, S. O.; Shemyakov, A. O.

    2017-12-01

    The problem of spacecraft attitude control using electromagnetic systems interacting with the Earth's magnetic field is considered. A set of dimensionless parameters has been formed to investigate the spacecraft orientation regimes based on dynamically similar models. The results of experimental studies of small spacecraft with a magnetic attitude control system can be extrapolated to the in-orbit spacecraft motion control regimes by using the methods of the dimensional and similarity theory.

  9. High-bandwidth and flexible tracking control for precision motion with application to a piezo nanopositioner.

    Science.gov (United States)

    Feng, Zhao; Ling, Jie; Ming, Min; Xiao, Xiao-Hui

    2017-08-01

    For precision motion, high-bandwidth and flexible tracking are the two important issues for significant performance improvement. Iterative learning control (ILC) is an effective feedforward control method only for systems that operate strictly repetitively. Although projection ILC can track varying references, the performance is still limited by the fixed-bandwidth Q-filter, especially for triangular waves tracking commonly used in a piezo nanopositioner. In this paper, a wavelet transform-based linear time-varying (LTV) Q-filter design for projection ILC is proposed to compensate high-frequency errors and improve the ability to tracking varying references simultaneously. The LVT Q-filter is designed based on the modulus maximum of wavelet detail coefficients calculated by wavelet transform to determine the high-frequency locations of each iteration with the advantages of avoiding cross-terms and segmenting manually. The proposed approach was verified on a piezo nanopositioner. Experimental results indicate that the proposed approach can locate the high-frequency regions accurately and achieve the best performance under varying references compared with traditional frequency-domain and projection ILC with a fixed-bandwidth Q-filter, which validates that through implementing the LTV filter on projection ILC, high-bandwidth and flexible tracking can be achieved simultaneously by the proposed approach.

  10. Hip and ankle range of motion and hip muscle strength in young female ballet dancersand controls

    Science.gov (United States)

    Bennell, K.; Khan, K. M.; Matthews, B.; De Gruyter, M.; Cook, E.; Holzer, K.; Wark, J. D.

    1999-01-01

    OBJECTIVES: To compare the hip and ankle range of motion and hip muscle strength in 8-11 year old novice female ballet dancers and controls. METHODS: Subjects were 77 dancers and 49 controls (mean (SD) age 9.6 (0.8) and 9.6 (0.7) years respectively). Supine right active hip external rotation (ER) and internal rotation (IR) were measured using an inclinometer. A turnout protractor was used to assess standing active turnout range. The measure of ER achieved from below the hip during turnout (non-hip ER) was calculated by subtracting hip ER range from turnout range, and hip ER:IR was derived by dividing ER range by IR range. Range of right weight bearing ankle dorsiflexion was measured in a standing lunge using two methods: the distance from the foot to the wall (in centimetres) and the angle of the shank to the vertical via an inclinometer (in degrees). Right calf muscle range was measured in weight bearing using an inclinometer. A manual muscle tester was used to assess right isometric hip flexor, internal rotator, external rotator, abductor, and adductor strength. RESULTS: Dancers had less ER (pballetic training. 


 PMID:10522638

  11. The influence of variable range of motion training on neuromuscular performance and control of external loads.

    Science.gov (United States)

    Clark, Ross A; Humphries, Brendan; Hohmann, Erik; Bryant, Adam L

    2011-03-01

    Resistance training programs that emphasize high force production in different regions of the range of motion (ROM) may provide performance benefits. This study examined whether variable ROM (VROM) training, which consists of partial ROM training with countermovements performed in a different phase of the ROM for each set, results in improved functional performance. Twenty-two athletes (age 22.7 ± 2.4 years, height 1.81 ± 0.07 m, and body mass 94.6 ± 14.5 kg) with extensive resistance training backgrounds performed either a VROM or full ROM control (CON) 5-week, concentric work-matched training program. The participants were assigned to a group based on stratified randomization incorporating their strength levels and performance gains in preceding training microcycles. Testing consisted of assessing the force-ROM relationship during isokinetic and isometric bench press and ballistic bench throws, with normalized electromyography amplitude assessed during the isometric tests. Repeated-measure analyses of variance revealed that the VROM intervention significantly (p force (+15.7%), in addition to isokinetic peak force in the terminal ROM (13.5% increase). No significant differences were observed in the CON group or between groups for any other outcome measures. Analysis of the force-ROM relationship revealed that that the VROM intervention enhanced performance at shorter muscle lengths. These findings suggest that VROM training improves terminal and midrange performance gains, resulting in the athlete possessing an improved ability to control external loading and produce dynamic force.

  12. An innovative optimal control approach for the next generation simulator motion platform DESDEMONA

    NARCIS (Netherlands)

    Mayrhofer, M.; Langwallner, B.; Schlüsselberger, R.; Bles, W.; Wentink, M.

    2007-01-01

    The very unique and novel motion platform DESDEMONA was taken into start-up operation early this year. This next generation motion platform allows 6-DoF movement combined with the capability of producing sustained g-forces. These features make the simulator extremely valuable for future flight

  13. GEOMETRIC PROPERTIES OF A MECHANICAL FORWARD MOTION COMPENSATION SYSTEM CONTROLLED BY A PIEZOELECTRIC DRIVE

    Directory of Open Access Journals (Sweden)

    F. Collette

    2012-07-01

    Full Text Available Forward Motion Compensation (FMC systems have been designed to ensure the radiometric quality of motion acquisition in airborne cameras. If the radiometric benefits of FMC have been acknowledged, what are its effects on the geometrical properties of the camera? This paper demonstrates that FMC significantly improves geometrical properties of a camera. Aspects of FMC theory are discussed, with a focus on the near-lossless implementation of this technology into digital aerial camera systems. Among mechanical FMC technologies, the piezoelectric drive is proving to excel in dynamic positioning in both accuracy and repeatability. The patented piezoelectric drive integrated into Optech aerial camera systems allows for continuous and precise sensor motion to ensure exact compensation of the aircraft's forward motion. This paper presents findings that demonstrate the validity of this assertion. The paper also discusses the physical principles involved in motion acquisition. Equations are included that define the motion effect at image level and illustrate how FMC acts to prevent motion effects. The residual motion effect or compensation error is formulated and a practical computation applied to the more restrictive camera case. The assessment concludes that, in the range of airborne camera utilization, the mechanical FMC technique is free of "visible" error at both human eye and computer assessment level. Lastly, the paper proceeds to a detailed technical discussion of piezoelectric drives and why they have proven to be so effective as nanopositioning devices for optical applications. The effectiveness of the patented piezoelectric drives used to achieve FMC in Optech cameras is conclusively demonstrated.

  14. Complexity Control of Fast Motion Estimation in H.264/MPEG-4 AVC with Rate-Distortion-Complexity optimization

    DEFF Research Database (Denmark)

    Wu, Mo; Forchhammer, Søren; Aghito, Shankar Manuel

    2007-01-01

    A complexity control algorithm for H.264 advanced video coding is proposed. The algorithm can control the complexity of integer inter motion estimation for a given target complexity. The Rate-Distortion-Complexity performance is improved by a complexity prediction model, simple analysis of the pa...... statistics and a control scheme. The algorithm also works well for scene change condition. Test results for coding interlaced video (720x576 PAL) are reported.......A complexity control algorithm for H.264 advanced video coding is proposed. The algorithm can control the complexity of integer inter motion estimation for a given target complexity. The Rate-Distortion-Complexity performance is improved by a complexity prediction model, simple analysis of the past...

  15. Auditory motion capturing ambiguous visual motion

    Directory of Open Access Journals (Sweden)

    Arjen eAlink

    2012-01-01

    Full Text Available In this study, it is demonstrated that moving sounds have an effect on the direction in which one sees visual stimuli move. During the main experiment sounds were presented consecutively at four speaker locations inducing left- or rightwards auditory apparent motion. On the path of auditory apparent motion, visual apparent motion stimuli were presented with a high degree of directional ambiguity. The main outcome of this experiment is that our participants perceived visual apparent motion stimuli that were ambiguous (equally likely to be perceived as moving left- or rightwards more often as moving in the same direction than in the opposite direction of auditory apparent motion. During the control experiment we replicated this finding and found no effect of sound motion direction on eye movements. This indicates that auditory motion can capture our visual motion percept when visual motion direction is insufficiently determinate without affecting eye movements.

  16. An Enhanced Intelligent Handheld Instrument with Visual Servo Control for 2-DOF Hand Motion Error Compensation

    Directory of Open Access Journals (Sweden)

    Yan Naing Aye

    2013-10-01

    Full Text Available The intelligent handheld instrument, ITrem2, enhances manual positioning accuracy by cancelling erroneous hand movements and, at the same time, provides automatic micromanipulation functions. Visual data is acquired from a high speed monovision camera attached to the optical surgical microscope and acceleration measurements are acquired from the inertial measurement unit (IMU on board ITrem2. Tremor estimation and canceling is implemented via Band-limited Multiple Fourier Linear Combiner (BMFLC filter. The piezoelectric actuated micromanipulator in ITrem2 generates the 3D motion to compensate erroneous hand motion. Preliminary bench-top 2-DOF experiments have been conducted. The error motions simulated by a motion stage is reduced by 67% for multiple frequency oscillatory motions and 56.16% for pre-conditioned recorded physiological tremor.

  17. Active-flux based motion sensorless vector control of biaxial excitation generator/motor for automobiles (BEGA)

    DEFF Research Database (Denmark)

    Coroban-Schramel, Vasile; Boldea, Ion; Andreescu, Gheorghe-Daniel

    2009-01-01

    This paper proposes a novel, active-flux based, motion-sensorless vector control structure for biaxial excitation generator for automobiles (BEGA) for wide speed range operation. BEGA is a hybrid excited synchronous machine having permanent magnets on q-axis and a dc excitation on daxis. Using th...... electrical degrees in less than 2 ms test time....

  18. Motion Control and Optical Interrogation of a Levitating Single Nitrogen Vacancy in Vacuum.

    Science.gov (United States)

    Conangla, Gerard P; Schell, Andreas W; Rica, Raúl A; Quidant, Romain

    2018-05-24

    Levitation optomechanics exploits the unique mechanical properties of trapped nano-objects in vacuum to address some of the limitations of clamped nanomechanical resonators. In particular, its performance is foreseen to contribute to a better understanding of quantum decoherence at the mesoscopic scale as well as to lead to novel ultrasensitive sensing schemes. While most efforts have focused so far on the optical trapping of low-absorption silica particles, further opportunities arise from levitating objects with internal degrees of freedom, such as color centers. Nevertheless, inefficient heat dissipation at low pressures poses a challenge because most nano-objects, even with low-absorption materials, experience photodamage in an optical trap. Here, by using a Paul trap, we demonstrate levitation in vacuum and center-of-mass feedback cooling of a nanodiamond hosting a single nitrogen-vacancy center. The achieved level of motion control enables us to optically interrogate and characterize the emitter response. The developed platform is applicable to a wide range of other nano-objects and represents a promising step toward coupling internal and external degrees of freedom.

  19. Input relegation control for gross motion of a kinematically redundant manipulator

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1992-10-01

    This report proposes a method for resolving the kinematic redundancy of a serial link manipulator moving in a three-dimensional workspace. The underspecified problem of solving for the joint velocities based on the classical kinematic velocity model is transformed into a well-specified problem. This is accomplished by augmenting the original model with additional equations which relate a new vector variable quantifying the redundant degrees of freedom (DOF) to the joint velocities. The resulting augmented system yields a well specified solution for the joint velocities. Methods for selecting the redundant DOF quantifying variable and the transformation matrix relating it to the joint velocities are presented so as to obtain a minimum Euclidean norm solution for the joint velocities. The approach is also applied to the problem of resolving the kinematic redundancy at the acceleration level. Upon resolving the kinematic redundancy, a rigid body dynamical model governing the gross motion of the manipulator is derived. A control architecture is suggested which according to the model, decouples the Cartesian space DOF and the redundant DOF.

  20. Exploring Direct 3D Interaction for Full Horizontal Parallax Light Field Displays Using Leap Motion Controller

    Directory of Open Access Journals (Sweden)

    Vamsi Kiran Adhikarla

    2015-04-01

    Full Text Available This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  1. Identification of motion from multi-channel EMG signals for control of prosthetic hand

    International Nuclear Information System (INIS)

    Geethanjali, P.; Ray, K.K.

    2011-01-01

    Full text: The authors in this paper propose an effective and efficient pattern recognition technique from four channel electromyogram (EMG) signals for control of multifunction prosthetic hand. Time domain features such as mean absolute value, number of zero crossings, number of slope sign changes and waveform length are considered for pattern recognition. The patterns are classified using simple logistic regression (SLR) technique and decision tree (DT) using J48 algorithm. In this study six specific hand and wrist motions are identified from the EMG signals obtained from ten different able-bodied. By considering relevant dominant features for pattern recognition, the processing time as well as memory space of the SLR and DT classifiers is found to be less in comparison with neural network (NN), k-nearest neighbour model 1 (kNN Model-1), k-nearest neighbour model 2 (kNN-Model-2) and linear discriminant analysis. The classification accuracy of SLR classifier is found to be 91 ± 1.9%. (author)

  2. Exploring direct 3D interaction for full horizontal parallax light field displays using leap motion controller.

    Science.gov (United States)

    Adhikarla, Vamsi Kiran; Sodnik, Jaka; Szolgay, Peter; Jakus, Grega

    2015-04-14

    This paper reports on the design and evaluation of direct 3D gesture interaction with a full horizontal parallax light field display. A light field display defines a visual scene using directional light beams emitted from multiple light sources as if they are emitted from scene points. Each scene point is rendered individually resulting in more realistic and accurate 3D visualization compared to other 3D displaying technologies. We propose an interaction setup combining the visualization of objects within the Field Of View (FOV) of a light field display and their selection through freehand gesture tracked by the Leap Motion Controller. The accuracy and usefulness of the proposed interaction setup was also evaluated in a user study with test subjects. The results of the study revealed high user preference for free hand interaction with light field display as well as relatively low cognitive demand of this technique. Further, our results also revealed some limitations and adjustments of the proposed setup to be addressed in future work.

  3. Predicting the Motions and Forces of Wearable Robotic Systems Using Optimal Control

    Directory of Open Access Journals (Sweden)

    Matthew Millard

    2017-08-01

    Full Text Available Wearable robotic systems are being developed to prevent injury to the low back. Designing a wearable robotic system is challenging because it is difficult to predict how the exoskeleton will affect the movement of the wearer. To aid the design of exoskeletons, we formulate and numerically solve an optimal control problem (OCP to predict the movements and forces of a person as they lift a 15 kg box from the ground both without (human-only OCP and with (with-exo OCP the aid of an exoskeleton. We model the human body as a sagittal-plane multibody system that is actuated by agonist and antagonist pairs of muscle torque generators (MTGs at each joint. Using the literature as a guide, we have derived a set of MTGs that capture the active torque–angle, passive torque–angle, and torque–velocity characteristics of the flexor and extensor groups surrounding the hip, knee, ankle, lumbar spine, shoulder, elbow, and wrist. Uniquely, these MTGs are continuous to the second derivative and so are compatible with gradient-based optimization. The exoskeleton is modeled as a rigid-body mechanism that is actuated by a motor at the hip and the lumbar spine and is coupled to the wearer through kinematic constraints. We evaluate our results by comparing our predictions with experimental recordings of a human subject. Our results indicate that the predicted peak lumbar-flexion angles and extension torques of the human-only OCP are within the range reported in the literature. The results of the with-exo OCP indicate that the exoskeleton motors should provide relatively little support during the descent to the box but apply a substantial amount of support during the ascent phase. The support provided by the lumbar motor is similar in shape to the net moment generated at the L5/S1 joint by the body; however, the support of the hip motor is more complex because it is coupled to the passive forces that are being generated by the hip extensors of the human subject

  4. Heterobimetallic porphyrin complexes displaying triple dynamics: coupled metal motions controlled by constitutional evolution.

    Science.gov (United States)

    Le Gac, Stéphane; Fusaro, Luca; Roisnel, Thierry; Boitrel, Bernard

    2014-05-07

    A bis-strap porphyrin ligand (1), with an overhanging carboxylic acid group on each side of the macrocycle, has been investigated toward the formation of dynamic libraries of bimetallic complexes with Hg(II), Cd(II), and Pb(II). Highly heteroselective metalation processes occurred in the presence of Pb(II), with Hg(II) or Cd(II) bound out-of-plane to the N-core and "PbOAc" bound to a carboxylate group of a strap on the opposite side. The resulting complexes, 1(Hg)·PbOAc and 1(Cd)·PbOAc, display three levels of dynamics. The first is strap-level (interactional dynamics), where the PbOAc moiety swings between the left and right side of the strap owing to a second sphere of coordination with lateral amide functions. The second is ligand-level (motional dynamics), where 1(Hg)·PbOAc and 1(Cd)·PbOAc exist as two degenerate states in equilibrium controlled by a chemical effector (AcO(-)). The process corresponds to a double translocation of the metal ions according to an intramolecular migration of Hg(II) or Cd(II) through the N-core, oscillating between the two equivalent overhanging carbonyl groups, coupled to an intermolecular pathway for PbOAc exchanging between the two equivalent overhanging carboxylate groups (N-core(up) ⇆ N-core(down) coupled to strap(down) ⇆ strap(up), i.e., coupled motion #1 in the abstract graphic). The third is library-level (constitutional dynamics), where a dynamic constitutional evolution of the system was achieved by the successive addition of two chemical effectors (DMAP and then AcO(-)). It allowed shifting equilibrium forward and backward between 1(Hg)·PbOAc and the corresponding homobimetallic complexes 1(Hg2)·DMAP and 1(Pb)·PbOAc. The latter displays a different ligand-level dynamics, in the form of an intraligand coupled migration of the Pb(II) ions (N-core(up) ⇆ strap(up) coupled to strap(down) ⇆ N-core(down), i.e., coupled motion #2 in the abstract graphic). In addition, the neutral "bridged" complexes 1HgPb and 1Cd

  5. Design of Fuzzy Enhanced Hierarchical Motion Stabilizing Controller of Unmanned Ground Vehicle in Three DimensionalSpace

    Directory of Open Access Journals (Sweden)

    Yue Ma

    2011-12-01

    Full Text Available In this paper, stabilizing control of tracked unmanned ground vehicle in 3-D space was presented. Firstly, models of major modules of tracked UGV were established. Next, to reveal the mechanism of disturbances applied on the UGV, two kinds of representative disturbances (slope and general disturbances in yaw motion were discussed in depth. Consequently, an attempting PID method was employed to compensate the impacts of disturbances andsimulation results proved the validity for disturbance incited by slope force, but revealed the lack for general disturbance on yaw motion. Finally, a hierarchical fuzzy controller combined with PID controller was proposed. In lower level, there were two PID controllers to compensate the disturbance of slope force, and on top level, the fuzzy logic controller was employed to correct the yaw motion error based on the differences between the model and the real UGV, which was able to guide the UGV maintain on the stable state. Simulation results demonstrated the excellent effectiveness of the newly designed controller.

  6. Weigh-in-Motion Sensor and Controller Operation and Performance Comparison

    Science.gov (United States)

    2018-01-01

    This research project utilized statistical inference and comparison techniques to compare the performance of different Weigh-in-Motion (WIM) sensors. First, we analyzed test-vehicle data to perform an accuracy check of the results reported by the sen...

  7. Use of portable in motion weight control technologies at landfill sites

    CSIR Research Space (South Africa)

    Fisher, D

    2006-09-01

    Full Text Available Requirements for landfilling. In-motion weighing technology currently available in South Africa was investigated to assess its suitability as a 'portable landfill weighbridge'. The experience gained through testing the portable weighpad technology has indicated...

  8. Binocular eye movement control and motion perception: what is being tracked?

    Science.gov (United States)

    van der Steen, Johannes; Dits, Joyce

    2012-10-19

    We investigated under what conditions humans can make independent slow phase eye movements. The ability to make independent movements of the two eyes generally is attributed to few specialized lateral eyed animal species, for example chameleons. In our study, we showed that humans also can move the eyes in different directions. To maintain binocular retinal correspondence independent slow phase movements of each eye are produced. We used the scleral search coil method to measure binocular eye movements in response to dichoptically viewed visual stimuli oscillating in orthogonal direction. Correlated stimuli led to orthogonal slow eye movements, while the binocularly perceived motion was the vector sum of the motion presented to each eye. The importance of binocular fusion on independency of the movements of the two eyes was investigated with anti-correlated stimuli. The perceived global motion pattern of anti-correlated dichoptic stimuli was perceived as an oblique oscillatory motion, as well as resulted in a conjugate oblique motion of the eyes. We propose that the ability to make independent slow phase eye movements in humans is used to maintain binocular retinal correspondence. Eye-of-origin and binocular information are used during the processing of binocular visual information, and it is decided at an early stage whether binocular or monocular motion information and independent slow phase eye movements of each eye are produced during binocular tracking.

  9. Trunk motion visual feedback during walking improves dynamic balance in older adults: Assessor blinded randomized controlled trial.

    Science.gov (United States)

    Anson, Eric; Ma, Lei; Meetam, Tippawan; Thompson, Elizabeth; Rathore, Roshita; Dean, Victoria; Jeka, John

    2018-05-01

    Virtual reality and augmented feedback have become more prevalent as training methods to improve balance. Few reports exist on the benefits of providing trunk motion visual feedback (VFB) during treadmill walking, and most of those reports only describe within session changes. To determine whether trunk motion VFB treadmill walking would improve over-ground balance for older adults with self-reported balance problems. 40 adults (75.8 years (SD 6.5)) with self-reported balance difficulties or a history of falling were randomized to a control or experimental group. Everyone walked on a treadmill at a comfortable speed 3×/week for 4 weeks in 2 min bouts separated by a seated rest. The control group was instructed to look at a stationary bulls-eye target while the experimental group also saw a moving cursor superimposed on the stationary bulls-eye that represented VFB of their walking trunk motion. The experimental group was instructed to keep the cursor in the center of the bulls-eye. Somatosensory (monofilaments and joint position testing) and vestibular function (canal specific clinical head impulses) was evaluated prior to intervention. Balance and mobility were tested before and after the intervention using Berg Balance Test, BESTest, mini-BESTest, and Six Minute Walk. There were no significant differences between groups before the intervention. The experimental group significantly improved on the BESTest (p = 0.031) and the mini-BEST (p = 0.019). The control group did not improve significantly on any measure. Individuals with more profound sensory impairments had a larger improvement on dynamic balance subtests of the BESTest. Older adults with self-reported balance problems improve their dynamic balance after training using trunk motion VFB treadmill walking. Individuals with worse sensory function may benefit more from trunk motion VFB during walking than individuals with intact sensory function. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Comparison of visual biofeedback system with a guiding waveform and abdomen-chest motion self-control system for respiratory motion management

    International Nuclear Information System (INIS)

    Nakajima, Yujiro; Kadoya, Noriyuki; Kanai, Takayuki; Ito, Kengo; Sato, Kiyokazu; Dobashi, Suguru; Yamamoto, Takaya; Ishikawa, Yojiro; Matsushita, Haruo; Takeda, Ken; Jingu, Keiichi

    2016-01-01

    Irregular breathing can influence the outcome of 4D computed tomography imaging and cause artifacts. Visual biofeedback systems associated with a patient-specific guiding waveform are known to reduce respiratory irregularities. In Japan, abdomen and chest motion self-control devices (Abches) (representing simpler visual coaching techniques without a guiding waveform) are used instead; however, no studies have compared these two systems to date. Here, we evaluate the effectiveness of respiratory coaching in reducing respiratory irregularities by comparing two respiratory management systems. We collected data from 11 healthy volunteers. Bar and wave models were used as visual biofeedback systems. Abches consisted of a respiratory indicator indicating the end of each expiration and inspiration motion. Respiratory variations were quantified as root mean squared error (RMSE) of displacement and period of breathing cycles. All coaching techniques improved respiratory variation, compared with free-breathing. Displacement RMSEs were 1.43 ± 0.84, 1.22 ± 1.13, 1.21 ± 0.86 and 0.98 ± 0.47 mm for free-breathing, Abches, bar model and wave model, respectively. Period RMSEs were 0.48 ± 0.42, 0.33 ± 0.31, 0.23 ± 0.18 and 0.17 ± 0.05 s for free-breathing, Abches, bar model and wave model, respectively. The average reduction in displacement and period RMSE compared with the wave model were 27% and 47%, respectively. For variation in both displacement and period, wave model was superior to the other techniques. Our results showed that visual biofeedback combined with a wave model could potentially provide clinical benefits in respiratory management, although all techniques were able to reduce respiratory irregularities

  11. Modern power converter drives. Drive systems, power electronics, machines, mechatronics and motion control. 5. rev. and enl. ed.; Moderne Stromrichterantriebe. Antriebssystem, Leistungselektronik, Maschinen, Mechatronik und Motion Control, Arbeitsweise drehzahlveraenderbarer Antriebe mit Stromrichtern und Antriebsvernetzung

    Energy Technology Data Exchange (ETDEWEB)

    Brosch, P.F.

    2008-07-01

    This book informs students and practicians on variable-speed drives. Constructional engineers, technicians and others are given a practical tool for their daily work. - Fundamentals of motive power engineering - power converter components - electric machines - power converter drives with commutator motors - power converter drives with induction machines - integrated drive systems - motion control and mechatronics - selection and dimensioning of variable-speed drives converter measuring engineering - electromagnetic compatibility, with examples - measurements on power converter drives with variable speed adjustment - electromagnetic compatibility. (orig./GL)

  12. Wrist range of motion and motion frequency during toy and game play with a joint-specific controller specially designed to provide neuromuscular therapy: A proof of concept study in typically developing children.

    Science.gov (United States)

    Crisco, Joseph J; Schwartz, Joel B; Wilcox, Bethany; Brideau, Holly; Basseches, Benjamin; Kerman, Karen

    2015-08-20

    Upper extremities affected by hemiplegic cerebral palsy (CP) and other neuromuscular disorders have been demonstrated to benefit from therapy, and the greater the duration of the therapy, the greater the benefit. A great motivator for participating in and extending the duration of therapy with children is play. Our focus is on active motion therapy of the wrist and forearm. In this study we examine the wrist motions associated with playing with two toys and three computer games controlled by a specially-designed play controller. Twenty children (ages 5-11) with no diagnosis of a muscular disorder were recruited. The play controller was fitted to the wrist and forearm of each child and used to measure and log wrist flexion and extension. Play activity and enjoyment were quantified by average wrist range of motion (ROM), motion frequency measures, and a discrete visual scale. We found significant differences in the average wrist ROM and motion frequency among the toys and games, yet there were no differences in the level of enjoyment across all toys and games, which was high. These findings indicate which toys and games may elicit the greater number of goal-directed movements, and lay the foundation for our long-term goal to develop and evaluate innovative motion-specific play controllers that are engaging rehabilitative devices for enhancing therapy and promoting neural plasticity and functional recovery in children with CP. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Effect of Continuous Motion Parameter Feedback on Laparoscopic Simulation Training: A Prospective Randomized Controlled Trial on Skill Acquisition and Retention.

    Science.gov (United States)

    Buescher, Julian Frederik; Mehdorn, Anne-Sophie; Neumann, Philipp-Alexander; Becker, Felix; Eichelmann, Ann-Kathrin; Pankratius, Ulrich; Bahde, Ralf; Foell, Daniel; Senninger, Norbert; Rijcken, Emile

    To investigate the effect of motion parameter feedback on laparoscopic basic skill acquisition and retention during a standardized box training curriculum. A Lap-X Hybrid laparoscopic simulator was designed to provide individual and continuous motion parameter feedback in a dry box trainer setting. In a prospective controlled trial, surgical novices were randomized into 2 groups (regular box group, n = 18, and Hybrid group, n = 18) to undergo an identical 5-day training program. In each group, 7 standardized tasks on laparoscopic basic skills were completed twice a day on 4 consecutive days in fixed pairs. Additionally, each participant performed a simulated standard laparoscopic cholecystectomy before (day 1) and after training (day 5) on a LAP Mentor II virtual reality (VR) trainer, allowing an independent control of skill progress in both groups. A follow-up assessment of skill retention was performed after 6 weeks with repetition of both the box tasks and VR cholecystectomy. Muenster University Hospital Training Center, Muenster, Germany. Medical students without previous surgical experience. Laparoscopic skills in both groups improved significantly during the training period, measured by the overall task performance time. The 6 week follow-up showed comparable skill retention in both groups. Evaluation of the VR cholecystectomies demonstrated significant decrease of operation time (p Simulation training on both trainers enables reliable acquisition of laparoscopic basic skills. Furthermore, individual and continuous motion feedback improves laparoscopic skill enhancement significantly in several aspects. Thus, training systems with feedback of motion parameters should be considered to achieve long-term improvement of motion economy among surgical trainees. Copyright © 2017 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  14. An Evolutionary Robotics Approach to the Control of Plant Growth and Motion: Modeling Plants and Crossing the Reality Gap

    DEFF Research Database (Denmark)

    Wahby, Mostafa; Hofstadler, Daniel Nicolas; Heinrich, Mary Katherine

    2016-01-01

    The self-organizing bio-hybrid collaboration of robots and natural plants allows for a variety of interesting applications. As an example we investigate how robots can be used to control the growth and motion of a natural plant, using LEDs to provide stimuli. We follow an evolutionary robotics...... approach where task performance is determined by monitoring the plant's reaction. First, we do initial plant experiments with simple, predetermined controllers. Then we use image sampling data as a model of the dynamics of the plant tip xy position. Second, we use this approach to evolve robot controllers...

  15. Software-controlled, highly automated intrafraction prostate motion correction with intrafraction stereographic targeting: System description and clinical results

    International Nuclear Information System (INIS)

    Mutanga, Theodore F.; Boer, Hans C. J. de; Rajan, Vinayakrishnan; Dirkx, Maarten L. P.; Os, Marjolein J. H. van; Incrocci, Luca; Heijmen, Ben J. M.

    2012-01-01

    Purpose: A new system for software-controlled, highly automated correction of intrafraction prostate motion,'' intrafraction stereographic targeting'' (iSGT), is described and evaluated. Methods: At our institute, daily prostate positioning is routinely performed at the start of treatment beam using stereographic targeting (SGT). iSGT was implemented by extension of the SGT software to facilitate fast and accurate intrafraction motion corrections with minimal user interaction. iSGT entails megavoltage (MV) image acquisitions with the first segment of selected IMRT beams, automatic registration of implanted markers, followed by remote couch repositioning to correct for intrafraction motion above a predefined threshold, prior to delivery of the remaining segments. For a group of 120 patients, iSGT with corrections for two nearly lateral beams was evaluated in terms of workload and impact on effective intrafraction displacements in the sagittal plane. Results: SDs of systematic (Σ) and random (σ) displacements relative to the planning CT measured directly after initial SGT setup correction were eff eff eff eff eff eff < 0.7 mm, requiring corrections in 82.4% of the fractions. Because iSGT is highly automated, the extra time added by iSGT is <30 s if a correction is required. Conclusions: Without increasing imaging dose, iSGT successfully reduces intrafraction prostate motion with minimal workload and increase in fraction time. An action level of 2 mm is recommended.

  16. The Relationship Between Engagement and Neurophysiological Measures of Attention in Motion-Controlled Video Games: A Randomized Controlled Trial.

    Science.gov (United States)

    Leiker, Amber M; Miller, Matthew; Brewer, Lauren; Nelson, Monica; Siow, Maria; Lohse, Keith

    2016-04-21

    Video games and virtual environments continue to be the subject of research in health sciences for their capacity to augment practice through user engagement. Creating game mechanics that increase user engagement may have indirect benefits on learning (ie, engaged learners are likely to practice more) and may also have direct benefits on learning (ie, for a fixed amount of practice, engaged learners show superior retention of information or skills). To manipulate engagement through the aesthetic features of a motion-controlled video game and measure engagement's influence on learning. A group of 40 right-handed participants played the game under two different conditions (game condition or sterile condition). The mechanics of the game and the amount of practice were constant. During practice, event-related potentials (ERPs) to task-irrelevant probe tones were recorded during practice as an index of participants' attentional reserve. Participants returned for retention and transfer testing one week later. Although both groups improved in the task, there was no difference in the amount of learning between the game and sterile groups, countering previous research. A new finding was a statistically significant relationship between self-reported engagement and the amplitude of the early-P3a (eP3a) component of the ERP waveform, such that participants who reported higher levels of engagement showed a smaller eP3a (beta=-.08, P=.02). This finding provides physiological data showing that engagement elicits increased information processing (reducing attentional reserve), which yields new insight into engagement and its underlying neurophysiological properties. Future studies may objectively index engagement by quantifying ERPs (specifically the eP3a) to task-irrelevant probes.

  17. Structural motion engineering

    CERN Document Server

    Connor, Jerome

    2014-01-01

    This innovative volume provides a systematic treatment of the basic concepts and computational procedures for structural motion design and engineering for civil installations. The authors illustrate the application of motion control to a wide spectrum of buildings through many examples. Topics covered include optimal stiffness distributions for building-type structures, the role of damping in controlling motion, tuned mass dampers, base isolation systems, linear control, and nonlinear control. The book's primary objective is the satisfaction of motion-related design requirements, such as restrictions on displacement and acceleration. The book is ideal for practicing engineers and graduate students. This book also: ·         Broadens practitioners' understanding of structural motion control, the enabling technology for motion-based design ·         Provides readers the tools to satisfy requirements of modern, ultra-high strength materials that lack corresponding stiffness, where the motion re...

  18. Decoupled pelvis adjustment to induce lumbar motion: A technique that controls low back load in sitting

    NARCIS (Netherlands)

    van Geffen, P.; Reenalda, Jasper; Veltink, Petrus H.; Koopman, Hubertus F.J.M.

    Static sitting in confined settings have been associated with low back pain in sedentary occupations such as office works and car driving. To prevent lumbar discomfort in prolonged static sitting, periodic motion of the lumbar spine is needed. Because the pelvis forms the basis for lumbar spine

  19. Motion compensation with skin contact control for high intensity focused ultrasound surgery in moving organs

    Science.gov (United States)

    Diodato, A.; Cafarelli, A.; Schiappacasse, A.; Tognarelli, S.; Ciuti, G.; Menciassi, A.

    2018-02-01

    High intensity focused ultrasound (HIFU) is an emerging therapeutic solution that enables non-invasive treatment of several pathologies, mainly in oncology. On the other hand, accurate targeting of moving abdominal organs (e.g. liver, kidney, pancreas) is still an open challenge. This paper proposes a novel method to compensate the physiological respiratory motion of organs during HIFU procedures, by exploiting a robotic platform for ultrasound-guided HIFU surgery provided with a therapeutic annular phased array transducer. The proposed method enables us to keep the same contact point between the transducer and the patient’s skin during the whole procedure, thus minimizing the modification of the acoustic window during the breathing phases. The motion of the target point is compensated through the rotation of the transducer around a virtual pivot point, while the focal depth is continuously adjusted thanks to the axial electronically steering capabilities of the HIFU transducer. The feasibility of the angular motion compensation strategy has been demonstrated in a simulated respiratory-induced organ motion environment. Based on the experimental results, the proposed method appears to be significantly accurate (i.e. the maximum compensation error is always under 1 mm), thus paving the way for the potential use of this technique for in vivo treatment of moving organs, and therefore enabling a wide use of HIFU in clinics.

  20. Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions – Changes in Accuracy over Time

    Science.gov (United States)

    Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

    2015-01-01

    Background Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven’t been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their

  1. The research of the coupled orbital-attitude controlled motion of celestial body in the neighborhood of the collinear libration point L1

    Science.gov (United States)

    Shmyrov, A.; Shmyrov, V.; Shymanchuk, D.

    2017-10-01

    This article considers the motion of a celestial body within the restricted three-body problem of the Sun-Earth system. The equations of controlled coupled attitude-orbit motion in the neighborhood of collinear libration point L1 are investigated. The translational orbital motion of a celestial body is described using Hill's equations of circular restricted three-body problem of the Sun-Earth system. Rotational orbital motion is described using Euler's dynamic equations and quaternion kinematic equation. We investigate the problem of stability of celestial body rotational orbital motion in relative equilibrium positions and stabilization of celestial body rotational orbital motion with proposed control laws in the neighborhood of collinear libration point L1. To study stabilization problem, Lyapunov function is constructed in the form of the sum of the kinetic energy and special "kinematic function" of the Rodriguez-Hamiltonian parameters. Numerical modeling of the controlled rotational motion of a celestial body at libration point L1 is carried out. The numerical characteristics of the control parameters and rotational motion are given.

  2. Meso-scale atmospheric events promote phytoplankton blooms in ...

    Indian Academy of Sciences (India)

    The Bay of Bengal is considered to be a low productive region compared to the Arabian Sea based on conventional seasonal observations. Such seasonal observations are not representative of a calendar year since the conventional approach might miss episodic high productive events associated with extreme ...

  3. High Precision Motion Control System for the Two-Stage Light Gas Gun at the Dynamic Compression Sector

    Science.gov (United States)

    Zdanowicz, E.; Guarino, V.; Konrad, C.; Williams, B.; Capatina, D.; D'Amico, K.; Arganbright, N.; Zimmerman, K.; Turneaure, S.; Gupta, Y. M.

    2017-06-01

    The Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS), located at Argonne National Laboratory (ANL), has a diverse set of dynamic compression drivers to obtain time resolved x-ray data in single event, dynamic compression experiments. Because the APS x-ray beam direction is fixed, each driver at DCS must have the capability to move through a large range of linear and angular motions with high precision to accommodate a wide variety of scientific needs. Particularly challenging was the design and implementation of the motion control system for the two-stage light gas gun, which rests on a 26' long structure and weighs over 2 tons. The target must be precisely positioned in the x-ray beam while remaining perpendicular to the gun barrel axis to ensure one-dimensional loading of samples. To accommodate these requirements, the entire structure can pivot through 60° of angular motion and move 10's of inches along four independent linear directions with 0.01° and 10 μm resolution, respectively. This presentation will provide details of how this system was constructed, how it is controlled, and provide examples of the wide range of x-ray/sample geometries that can be accommodated. Work supported by DOE/NNSA.

  4. Implementation and Validation of EtherCAT Support in Integrated Development Environment for Synchronized Motion Control Application

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jongbo; Kim, Chaerin; Kim, Ikhwan; Kim, Youngdong; Kim, Taehyoun [Univ. of Seoul, Seoul (Korea, Republic of)

    2014-02-15

    Recently, software-based programmable logic controller (PLC) systems, which are implemented in standard PLC languages on general hardware, are gaining popularity because they overcome the limitations of classical hardware PLC systems. Another noticeable trend is that the use of integrated development environment (IDE) is becoming important. IDEs can help developers to easily manage the growing complexity of modern control systems. Furthermore, industrial Ethernet, e. g. EtherCAT, is becoming widely accepted as a replacement for conventional fieldbuses in the distributed control domain because it offers favorable features such as short transmission delay, high bandwidth, and low cost. In this paper, we implemented the extension of open source IDE, called Beremiz, for developing EtherCAT-based real-time, synchronized motion control applications. We validated the EtherCAT system management features and the real-time responsiveness of the control function by using commercial EtherCAT drives and evaluation boards.

  5. Evolved Control of Natural Plants: Crossing the Reality Gap for User-Defined Steering of Growth and Motion

    DEFF Research Database (Denmark)

    Hofstadler, Daniel Nicolas; Wahby, Mostafa; Heinrich, Mary Katherine

    2017-01-01

    Mixing societies of natural and artificial systems can provide interesting and potentially fruitful research targets. Here we mix robotic setups and natural plants in order to steer the motion behavior of plants while growing. The robotic setup uses a camera to observe the plant and uses a pair...... of light sources to trigger phototropic response, steering the plant to user-defined targets. An evolutionary robotic approach is used to design a controller for the setup. Initially, preliminary experiments are performed with a simple predetermined controller and a growing bean plant. The plant behavior......-evolved controller in the real setup controlling a natural bean plant. The results demonstrate a successful crossing of the reality gap in the setup. The success of the approach allows for future extensions to more complex tasks including control of the shape of plants and pattern formation in multiple plant setups....

  6. Affine Transform to Reform Pixel Coordinates of EOG Signals for Controlling Robot Manipulators Using Gaze Motions

    Directory of Open Access Journals (Sweden)

    Muhammad Ilhamdi Rusydi

    2014-06-01

    Full Text Available Biosignals will play an important role in building communication between machines and humans. One of the types of biosignals that is widely used in neuroscience are electrooculography (EOG signals. An EOG has a linear relationship with eye movement displacement. Experiments were performed to construct a gaze motion tracking method indicated by robot manipulator movements. Three operators looked at 24 target points displayed on a monitor that was 40 cm in front of them. Two channels (Ch1 and Ch2 produced EOG signals for every single eye movement. These signals were converted to pixel units by using the linear relationship between EOG signals and gaze motion distances. The conversion outcomes were actual pixel locations. An affine transform method is proposed to determine the shift of actual pixels to target pixels. This method consisted of sequences of five geometry processes, which are translation-1, rotation, translation-2, shear and dilatation. The accuracy was approximately 0.86° ± 0.67° in the horizontal direction and 0.54° ± 0.34° in the vertical. This system successfully tracked the gaze motions not only in direction, but also in distance. Using this system, three operators could operate a robot manipulator to point at some targets. This result shows that the method is reliable in building communication between humans and machines using EOGs.

  7. Affine transform to reform pixel coordinates of EOG signals for controlling robot manipulators using gaze motions.

    Science.gov (United States)

    Rusydi, Muhammad Ilhamdi; Sasaki, Minoru; Ito, Satoshi

    2014-06-10

    Biosignals will play an important role in building communication between machines and humans. One of the types of biosignals that is widely used in neuroscience are electrooculography (EOG) signals. An EOG has a linear relationship with eye movement displacement. Experiments were performed to construct a gaze motion tracking method indicated by robot manipulator movements. Three operators looked at 24 target points displayed on a monitor that was 40 cm in front of them. Two channels (Ch1 and Ch2) produced EOG signals for every single eye movement. These signals were converted to pixel units by using the linear relationship between EOG signals and gaze motion distances. The conversion outcomes were actual pixel locations. An affine transform method is proposed to determine the shift of actual pixels to target pixels. This method consisted of sequences of five geometry processes, which are translation-1, rotation, translation-2, shear and dilatation. The accuracy was approximately 0.86° ± 0.67° in the horizontal direction and 0.54° ± 0.34° in the vertical. This system successfully tracked the gaze motions not only in direction, but also in distance. Using this system, three operators could operate a robot manipulator to point at some targets. This result shows that the method is reliable in building communication between humans and machines using EOGs.

  8. Adaptive robust motion trajectory tracking control of pneumatic cylinders with LuGre model-based friction compensation

    Science.gov (United States)

    Meng, Deyuan; Tao, Guoliang; Liu, Hao; Zhu, Xiaocong

    2014-07-01

    Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation (RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This

  9. On the correlation between motion data captured from low-cost gaming controllers and high precision encoders.

    Science.gov (United States)

    Purkayastha, Sagar N; Byrne, Michael D; O'Malley, Marcia K

    2012-01-01

    Gaming controllers are attractive devices for research due to their onboard sensing capabilities and low-cost. However, a proper quantitative analysis regarding their suitability for use in motion capture, rehabilitation and as input devices for teleoperation and gesture recognition has yet to be conducted. In this paper, a detailed analysis of the sensors of two of these controllers, the Nintendo Wiimote and the Sony Playstation 3 Sixaxis, is presented. The acceleration and angular velocity data from the sensors of these controllers were compared and correlated with computed acceleration and angular velocity data derived from a high resolution encoder. The results show high correlation between the sensor data from the controllers and the computed data derived from the position data of the encoder. From these results, it can be inferred that the Wiimote is more consistent and better suited for motion capture applications and as an input device than the Sixaxis. The applications of the findings are discussed with respect to potential research ventures.

  10. Co-Design Based Lateral Motion Control of All-Wheel-Independent-Drive Electric Vehicles with Network Congestion

    Directory of Open Access Journals (Sweden)

    Wanke Cao

    2017-10-01

    Full Text Available All-wheel-independent-drive electric vehicles (AWID-EVs have considerable advantages in terms of energy optimization, drivability and driving safety due to the remarkable actuation flexibility of electric motors. However, in their current implementations, various real-time data in the vehicle control system are exchanged via a controller area network (CAN, which causes network congestion and network-induced delays. These problems could lead to systemic instability and make the system integration difficult. The goal of this paper is to provide a design methodology that can cope with all these challenges for the lateral motion control of AWID-EVs. Firstly, a continuous-time model of an AWID-EV is derived. Then an expression for determining upper and lower bounds on the delays caused by CAN is presented and with which a discrete-time model of the closed-loop CAN system is derived. An expression on the bandwidth utilization is introduced as well. Thirdly, a co-design based scheme combining a period-dependent linear quadratic regulator (LQR and a dynamic period scheduler is designed for the resulting model and the stability criterion is also derived. The results of simulations and hard-in-loop (HIL experiments show that the proposed methodology can effectively guarantee the stability of the vehicle lateral motion control while obviously declining the network congestion.

  11. High Performance Motion-Planner Architecture for Hardware-In-the-Loop System Based on Position-Based-Admittance-Control

    Directory of Open Access Journals (Sweden)

    Francesco La Mura

    2018-02-01

    Full Text Available This article focuses on a Hardware-In-the-Loop application developed from the advanced energy field project LIFES50+. The aim is to replicate, inside a wind gallery test facility, the combined effect of aerodynamic and hydrodynamic loads on a floating wind turbine model for offshore energy production, using a force controlled robotic device, emulating floating substructure’s behaviour. In addition to well known real-time Hardware-In-the-Loop (HIL issues, the particular application presented has stringent safety requirements of the HIL equipment and difficult to predict operating conditions, so that extra computational efforts have to be spent running specific safety algorithms and achieving desired performance. To meet project requirements, a high performance software architecture based on Position-Based-Admittance-Control (PBAC is presented, combining low level motion interpolation techniques, efficient motion planning, based on buffer management and Time-base control, and advanced high level safety algorithms, implemented in a rapid real-time control architecture.

  12. Motion of the two-control airplane in rectilinear flight after initial disturbances with introduction of controls following an exponential law

    Science.gov (United States)

    Klemin, Alexander

    1937-01-01

    An airplane in steady rectilinear flight was assumed to experience an initial disturbance in rolling or yawing velocity. The equations of motion were solved to see if it was possible to hasten recovery of a stable airplane or to secure recovery of an unstable airplane by the application of a single lateral control following an exponential law. The sample computations indicate that, for initial disturbances complex in character, it would be difficult to secure correlation with any type of exponential control. The possibility is visualized that the two-control operation may seriously impair the ability to hasten recovery or counteract instability.

  13. Modification of Otolith-Ocular Reflexes, Motion Perception and Manual Control During Variable Radius Centrifugation Following Space Flight

    Science.gov (United States)

    Wood, Scott J.; Clarke, A. H.; Rupert, A. H.; Harm, D. L.; Clement, G. R.

    2009-01-01

    Two joint ESA-NASA studies are examining changes in otolith-ocular reflexes and motion perception following short duration space flights, and the operational implications of post-flight tilt-translation ambiguity for manual control performance. Vibrotactile feedback of tilt orientation is also being evaluated as a countermeasure to improve performance during a closed-loop nulling task. Data is currently being collected on astronaut subjects during 3 preflight sessions and during the first 8 days after Shuttle landings. Variable radius centrifugation is utilized to elicit otolith reflexes in the lateral plane without concordant roll canal cues. Unilateral centrifugation (400 deg/s, 3.5 cm radius) stimulates one otolith positioned off-axis while the opposite side is centered over the axis of rotation. During this paradigm, roll-tilt perception is measured using a subjective visual vertical task and ocular counter-rolling is obtained using binocular video-oculography. During a second paradigm (216 deg/s, less than 20 cm radius), the effects of stimulus frequency (0.15 - 0.6 Hz) are examined on eye movements and motion perception. A closed-loop nulling task is also performed with and without vibrotactile display feedback of chair radial position. Data collection is currently ongoing. Results to date suggest there is a trend for perceived tilt and translation amplitudes to be increased at the low and medium frequencies on landing day compared to pre-flight. Manual control performance is improved with vibrotactile feedback. One result of this study will be to characterize the variability (gain, asymmetry) in both otolith-ocular responses and motion perception during variable radius centrifugation, and measure the time course of post-flight recovery. This study will also address how adaptive changes in otolith-mediated reflexes correspond to one's ability to perform closed-loop nulling tasks following G-transitions, and whether manual control performance can be improved

  14. Leap motion controlled videogame-based therapy for rehabilitation of elderly patients with subacute stroke: a feasibility pilot study.

    Science.gov (United States)

    Iosa, Marco; Morone, Giovanni; Fusco, Augusto; Castagnoli, Marcello; Fusco, Francesca Romana; Pratesi, Luca; Paolucci, Stefano

    2015-08-01

    The leap motion controller (LMC) is a new optoelectronic system for capturing motion of both hands and controlling a virtual environment. Differently from previous devices, it optoelectronically tracks the fine movements of fingers neither using glows nor markers. This pilot study explored the feasibility of adapting the LMC, developed for videogames, to neurorehabilitation of elderly with subacute stroke. Four elderly patients (71.50 ± 4.51 years old) affected by stroke in subacute phase were enrolled and tested in a cross-over pilot trial in which six sessions of 30 minutes of LMC videogame-based therapy were added on conventional therapy. Measurements involved participation to the sessions, evaluated by means of the Pittsburgh Rehabilitation Participation Scale, hand ability and grasp force evaluated respectively by means of the Abilhand Scale and by means of the dynamometer. Neither adverse effects nor spasticity increments were observed during LMC training. Participation to the sessions was excellent in three patients and very good in one patient during the LMC trial. In this period, patients showed a significantly higher improvement in hand abilities (P = 0.028) and grasp force (P = 0.006). This feasibility pilot study was the first one using leap motion controller for conducting a videogame-based therapy. This study provided a proof of concept that LMC can be a suitable tool even for elderly patients with subacute stroke. LMC training was in fact performed with a high level of active participation, without adverse effects, and contributed to increase the recovery of hand abilities.

  15. 14 CFR 23.779 - Motion and effect of cockpit controls.

    Science.gov (United States)

    2010-01-01

    ... roll trim control may be displaced to accommodate comfortable actuation by the pilot. For single-engine... pressure. Rotary controls Clockwise from off to full on. (2) Auxiliary controls: Fuel tank selector Right...

  16. Predictive fault-tolerant control of an all-thruster satellite in 6-DOF motion via neural network model updating

    Science.gov (United States)

    Tavakoli, M. M.; Assadian, N.

    2018-03-01

    The problem of controlling an all-thruster spacecraft in the coupled translational-rotational motion in presence of actuators fault and/or failure is investigated in this paper. The nonlinear model predictive control approach is used because of its ability to predict the future behavior of the system. The fault/failure of the thrusters changes the mapping between the commanded forces to the thrusters and actual force/torque generated by the thruster system. Thus, the basic six degree-of-freedom kinetic equations are separated from this mapping and a set of neural networks are trained off-line to learn the kinetic equations. Then, two neural networks are attached to these trained networks in order to learn the thruster commands to force/torque mappings on-line. Different off-nominal conditions are modeled so that neural networks can detect any failure and fault, including scale factor and misalignment of thrusters. A simple model of the spacecraft relative motion is used in MPC to decrease the computational burden. However, a precise model by the means of orbit propagation including different types of perturbation is utilized to evaluate the usefulness of the proposed approach in actual conditions. The numerical simulation shows that this method can successfully control the all-thruster spacecraft with ON-OFF thrusters in different combinations of thruster fault and/or failure.

  17. Semi-active Control of Shallow Cables with Magnetorheological Dampers under Harmonic Axial Support Motion

    DEFF Research Database (Denmark)

    Zhou, Q.; Nielsen, Søren R.K.; Qu, W.L.

    2007-01-01

    amplitude is located in a certain range for the case OE2o1/3, the original zero out-of-plane vibration of the cable should be changed to the stable in-plane and out-of-plane coupled oscillation by using the optimal passive viscous damper or the MR damper with the SA-1 rule. It is also observed...... to the first in-plane eigenmode of the cable. The numerical results show that the MR damper with the SA-1 rule and the optimal viscous damper perform similarly to mitigate the vibration of the cable under axial periodic support motion, and, in some cases, the SA-2 rule is more favourable in suppressing...... the cable vibration compared with the SA-1 rule. In the final analysis, both the MR damper and the viscous damper can effectively mitigate the out-of-plane component of the cable, while having little effect on the reduction of the in-plane response in most cases. Furthermore, when the support motion...

  18. An artificial-vision responsive to patient motions during computer controlled radiation therapy

    International Nuclear Information System (INIS)

    Kalend, A.M.; Shimoga, K.; Kanade, T.; Greenberger, J.S.

    1997-01-01

    Purpose/Objectives: Automated precision radiotherapy using multiple conformal and modulated beams, requires monitoring of patient movements during irradiation. Immobilizers relying on patient cooperating in cradles have somewhat reduced positional uncertainties, but others including breathing are largely unknown. We built an artificial vision (AV) device for real-time vision of patient movements, their tracking and quantification. Method and Materials: The Artificial Vision System's 'acuity' and 'reflex' were evaluated in terms of imaged skin spatial resolutions and temporal dispersions measured using a mannequin and a fiduciated harmonic oscillator placed at 100cm isocenter. The device traced skin motion even in poorly lighted rooms without use of explicit skin fiduciation, or using standard radiotherapy skin tattoos. Results: The AV system tracked human skin at vision rates approaching 30Hz and sensitivity of 2mm. It successfully identified and tracked independent skin marks, either natural tattoos or artificial fiducials. Three alert levels triggered when patient movement exceeded preset displacements (2mm/30Hz), motion velocities (5m/sec) or acceleration (2m/sec 2 ). Conclusion: The AV system trigger should suit for patient ventilatory gating and safety interlocking of treatment accelerators, in order to modulate, interrupt, or abort radiation during dynamic therapy

  19. Coupling intensity and isostatic competition between subducting slab and overriding plate control trench motions and tectonics of the overriding plate

    Science.gov (United States)

    Wu, G.; Moresi, L. N.

    2017-12-01

    Trench motions not only reflect tectonic regimes on the overriding plate but also shed light on the competition between subducting slab and overriding plate, however, major controls over trench advance or retreat and their consequences are still illusive. We use 2D thermo-mechanical experiments to study the problem. We find that the coupling intensity particularly in the uppermost 200 km and the isostatic competition between subducting slab and overriding plate largely determine trench motion and tectonics of in the overriding plate. Coupling intensity is the result of many contributing factors, including frictional coefficient of brittle part of the subducting interface and the viscosity of the ductile part, thermal regime and rheology of the overriding plate, and water contents and magmatic activity in the subducting slab and overriding plate. In this study, we are not concerned with the dynamic evolution of individual controlling parameter but simply use effective media. For instance, we impose simple model parameters such as frictional coefficient and vary the temperature and strain-rate dependent viscosity of the weak layer between the subducting slab and overriding plate. In the coupled end-member case, strong coupling leads to strong corner flow, depth-dependent compression/extension, and mantle return flow on the overriding plate side. It results in fast trench retreat, broad overriding plate extension, and even slab breakoff. In the decoupled end-member case, weak coupling causes much weaker response on the overriding plate side compared with the coupled end-member case, and the subducting slab can be largely viewed as a conveyer belt. We find that the isostatic competition between the subducting slab and overriding plate also has a major control over trench motion, and may better be viewed in 3D models. This is consistent with the findings in previous 3D studies that trench motion is most pronounced close to the slab edge. Here we propose that the

  20. Alendronate treatment in the revision setting, with and without controlled implant motion

    DEFF Research Database (Denmark)

    Søballe, Kjeld; Chen, Xinqian; Jensen, Thomas B

    2007-01-01

    Introduction Bisphosphonates have been proposed to delay or prevent loosening of joint replacement implants by reducing bone resorption. It is known, however, that implant motion prevents the bone anchorage necessary to maintain secure implant fixation. Methods We used our experimental implant...... conditions, even with alendronate. With alendronate and stabilized implants, increased bone was observed near the sclerotic shell of the revision cavity, but it was reduced with alendronate when the implant was unstable. Interpretation Our findings suggest that it may be difficult for alendronate...... administration alone to rescue implants that are already loose. In implants that have not progressed to loosening, alendronate may increase bone density at the border with the sclerotic shell, but the effect of this bone in delaying eventual loosening is not known. Udgivelsesdato: 2007-Dec...

  1. Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

    Science.gov (United States)

    Liu, Lei; Bai, Yu-Guang; Zhang, Da-Li; Wu, Zhi-Gang

    2013-01-01

    The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS) and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS) error of 0.21 μrad, which is approximately equal to the noise level. PMID:23860316

  2. Ultra-Precision Measurement and Control of Angle Motion in Piezo-Based Platforms Using Strain Gauge Sensors and a Robust Composite Controller

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Wu

    2013-07-01

    Full Text Available The measurement and control strategy of a piezo-based platform by using strain gauge sensors (SGS and a robust composite controller is investigated in this paper. First, the experimental setup is constructed by using a piezo-based platform, SGS sensors, an AD5435 platform and two voltage amplifiers. Then, the measurement strategy to measure the tip/tilt angles accurately in the order of sub-μrad is presented. A comprehensive composite control strategy design to enhance the tracking accuracy with a novel driving principle is also proposed. Finally, an experiment is presented to validate the measurement and control strategy. The experimental results demonstrate that the proposed measurement and control strategy provides accurate angle motion with a root mean square (RMS error of 0.21 μrad, which is approximately equal to the noise level.

  3. Possible applications of the LEAP motion controller for more interactive simulated experiments in augmented or virtual reality

    Science.gov (United States)

    Wozniak, Peter; Vauderwange, Oliver; Mandal, Avikarsha; Javahiraly, Nicolas; Curticapean, Dan

    2016-09-01

    Practical exercises are a crucial part of many curricula. Even simple exercises can improve the understanding of the underlying subject. Most experimental setups require special hardware. To carry out e. g. a lens experiments the students need access to an optical bench, various lenses, light sources, apertures and a screen. In our previous publication we demonstrated the use of augmented reality visualization techniques in order to let the students prepare with a simulated experimental setup. Within the context of our intended blended learning concept we want to utilize augmented or virtual reality techniques for stationary laboratory exercises. Unlike applications running on mobile devices, stationary setups can be extended more easily with additional interfaces and thus allow for more complex interactions and simulations in virtual reality (VR) and augmented reality (AR). The most significant difference is the possibility to allow interactions beyond touching a screen. The LEAP Motion controller is a small inexpensive device that allows for the tracking of the user's hands and fingers in three dimensions. It is conceivable to allow the user to interact with the simulation's virtual elements by the user's very hand position, movement and gesture. In this paper we evaluate possible applications of the LEAP Motion controller for simulated experiments in augmented and virtual reality. We pay particular attention to the devices strengths and weaknesses and want to point out useful and less useful application scenarios.

  4. Active control with delay of catastrophic motion and horseshoes chaos in a single well Duffing oscillator

    International Nuclear Information System (INIS)

    Nana Nbendjo, B.R.; Salissou, Y.; Woafo, P.

    2005-01-01

    In this paper, the control of escape and Melnikov chaos of an harmonically excited particle from a catastrophic (unbounded) single well phi 4 potential is considered. In the linear limit, the range of the control gain parameter leading to good control is obtained and the effect of time delays on the control force is taken into account. The approximate critical external forcing amplitudes for catastrophe and chaos are obtained by using the energy and Melnikov methods. The control efficiency is found by analysing the behaviour of the external critical forcing amplitude of the controlled system as compared to that of the uncontrolled system

  5. Control-Informed Geometric Optimization of Wave Energy Converters: The Impact of Device Motion and Force Constraints

    Directory of Open Access Journals (Sweden)

    Paula B. Garcia-Rosa

    2015-12-01

    Full Text Available The energy cost for producing electricity via wave energy converters (WECs is still not competitive with other renewable energy sources, especially wind energy. It is well known that energy maximising control plays an important role to improve the performance of WECs, allowing the energy conversion to be performed as economically as possible. The control strategies are usually subsequently employed on a device that was designed and optimized in the absence of control for the prevailing sea conditions in a particular location. If an optimal unconstrained control strategy, such as pseudo-spectral optimal control (PSOC, is adopted, an overall optimized system can be obtained no matter whether the control design is incorporated at the geometry optimization stage or not. Nonetheless, strategies, such as latching control (LC, must be incorporated at the optimization design stage of the WEC geometry if an overall optimized system is to be realised. In this paper, the impact of device motion and force constraints in the design of control-informed optimized WEC geometries is addressed. The aim is to verify to what extent the constraints modify the connection between the control and the optimal device design. Intuitively, one might expect that if the constraints are very tight, the optimal device shape is the same regardless of incorporating or not the constrained control at the geometry optimization stage. However, this paper tests the hypothesis that the imposition of constraints will limit the control influence on the optimal device shape. PSOC, LC and passive control (PC are considered in this study. In addition, constrained versions of LC and PC are presented.

  6. A novel motion sensor-driven control system for FES-assisted walking after spinal cord injury: A pilot study.

    Science.gov (United States)

    Braz, Gustavo P; Russold, Michael F; Fornusek, Che; Hamzaid, Nur Azah; Smith, Richard M; Davis, Glen M

    2016-11-01

    This pilot study reports the development of a novel closed-loop (CL) FES-gait control system, which employed a finite-state controller that processed kinematic feedback from four miniaturized motion sensors. This strategy automated the control of knee extension via quadriceps and gluteus stimulation during the stance phase of gait on the supporting leg, and managed the stimulation delivered to the common peroneal nerve (CPN) during swing-phase on the contra-lateral limb. The control system was assessed against a traditional open-loop (OL) system on two sensorimotor 'complete' paraplegic subjects. A biomechanical analysis revealed that the closed-loop control of leg swing was efficient, but without major advantages compared to OL. CL automated the control of knee extension during the stance phase of gait and for this reason was the method of preference by the subjects. For the first time, a feedback control system with a simplified configuration of four miniaturized sensors allowed the addition of instruments to collect the data of multiple physiological and biomechanical variables during FES-evoked gait. In this pilot study of two sensorimotor complete paraplegic individuals, CL ameliorated certain drawbacks of current OL systems - it required less user intervention and accounted for the inter-subject differences in their stimulation requirements. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

  7. Tools for functional analysis of faults and methods of fault-stable motion control

    International Nuclear Information System (INIS)

    Timofeev, A.V.

    2003-01-01

    In this article a big attention is given to the problems of functional diagnostics, when control and faults diagnostics are made in real time simultaneously in the process of functioning of controlled dynamical systems

  8. System identification for robust and inferential control : with applications to ILC and precision motion systems

    NARCIS (Netherlands)

    Oomen, T.A.E.

    2010-01-01

    Feedback control is able to improve the performance of systems in the presence of uncertain dynamical behavior and disturbances. Although a properly designed controller can cope with large uncertainty, certain knowledge regarding the system behavior is crucial for control design. Hence, high

  9. Modeling Attitude Dynamics in Simulink: A Study of the Rotational and Translational Motion of a Spacecraft Given Torques and Impulses Generated by RMS Hand Controllers

    Science.gov (United States)

    Mauldin, Rebecca H.

    2010-01-01

    In order to study and control the attitude of a spacecraft, it is necessary to understand the natural motion of a body in orbit. Assuming a spacecraft to be a rigid body, dynamics describes the complete motion of the vehicle by the translational and rotational motion of the body. The Simulink Attitude Analysis Model applies the equations of rigid body motion to the study of a spacecraft?s attitude in orbit. Using a TCP/IP connection, Matlab reads the values of the Remote Manipulator System (RMS) hand controllers and passes them to Simulink as specified torque and impulse profiles. Simulink then uses the governing kinematic and dynamic equations of a rigid body in low earth orbit (LE0) to plot the attitude response of a spacecraft for five seconds given known applied torques and impulses, and constant principal moments of inertia.

  10. Development of constrained motion control for robot handling of hazardous waste

    International Nuclear Information System (INIS)

    Starr, G.P.

    1993-01-01

    Handling and archiving of hazardous waste is an area where automation and robotics can be of significant benefit, by removing the human operator from the workplace and its associated hazards. For reasons of safety, throughput, and reduced setup time, force-controlled robots are well-suited for hazardous materials handling. The focus of this investigation is the development of advanced force control techniques for commercial industrial robots in the surface sampling of hazardous waste containers. Two particular control strategies are considered, (1) preview control, and (2) adaptive control. Preview control uses a sensor which can ''look ahead'' and thereby reduce the effect of surface irregularity on contact force control. Adaptive control allows the robot controller to compensate for changes in the robot characteristics as it changes position, and likewise improves performance. The resulting control algorithms will be applied to a two-dimensional contour-following task using a PUMA robot at the Robotics Research Laboratory at The University of New Mexico. (author) 9 figs., 13 refs

  11. Terapia baseada em realidade virtual usando o leap motion controller para reabilitação do membro superior após acidente vascular cerebral = Virtual reality therapy using the leap motion controller for post-stroke upper limb rehabilitation Virtual reality therapy using the Leap Motion Controller for post-stroke upper limb rehabilitation

    Directory of Open Access Journals (Sweden)

    Soares, Nayron Medeiros

    2017-01-01

    Full Text Available OBJETIVOS: Avaliar a aplicabilidade de um sensor de movimento, baseado em realidade virtual, para promover a reabilitação do membro superior após um acidente vascular cerebral. RELATO DOS CASOS: Três pacientes após acidente vascular cerebral realizaram um treino para reabilitação do membro superior com realidade virtual usando a tecnologia Leap Motion Controller e o jogo Playground 3D®, durante três dias consecutivos. No primeiro e no terceiro dia, foram avaliados com os testes Caixa e Blocos, Coordenação Óculo-Manual de Melo e Estimulação Magnética Transcraniana. No último dia, foram aplicadas Fichas de Avaliação da Experiência do paciente. Após o treinamento proposto, observou-se diminuição do limiar motor em ambos os hemisférios cerebrais e melhores desempenhos nos testes que avaliaram a habilidade manual e óculo-manual. A terapia proposta foi bem recebida pelos pacientes testados. CONCLUSÕES: Não foram observados efeitos adversos e os resultados mostram-se promissores e precisos no treinamento realizado com realidade virtual usando a tecnologia Leap Motion Controller e o jogo Playground 3D®. O treinamento proporcionou uma participação ativa dos pacientes na reabilitação das sequelas de extremidade superior após um acidente vascular cerebral

  12. Methods for validating the performance of wearable motion-sensing devices under controlled conditions

    International Nuclear Information System (INIS)

    Bliley, Kara E; Kaufman, Kenton R; Gilbert, Barry K

    2009-01-01

    This paper presents validation methods for assessing the accuracy and precision of motion-sensing device (i.e. accelerometer) measurements. The main goals of this paper were to assess the accuracy and precision of these measurements against a gold standard, to determine if differences in manufacturing and assembly significantly affected device performance and to determine if measurement differences due to manufacturing and assembly could be corrected by applying certain post-processing techniques to the measurement data during analysis. In this paper, the validation of a posture and activity detector (PAD), a device containing a tri-axial accelerometer, is described. Validation of the PAD devices required the design of two test fixtures: a test fixture to position the device in a known orientation, and a test fixture to rotate the device at known velocities and accelerations. Device measurements were compared to these known orientations and accelerations. Several post-processing techniques were utilized in an attempt to reduce variability in the measurement error among the devices. In conclusion, some of the measurement errors due to the inevitable differences in manufacturing and assembly were significantly improved (p < 0.01) by these post-processing techniques

  13. Coupled motions in the SH2 and kinase domains of Csk control Src phosphorylation.

    Science.gov (United States)

    Wong, Lilly; Lieser, Scot A; Miyashita, Osamu; Miller, Meghan; Tasken, Kjetil; Onuchic, Josè N; Adams, Joseph A; Woods, Virgil L; Jennings, Patricia A

    2005-08-05

    The C-terminal Src kinase (Csk) phosphorylates and down-regulates Src family tyrosine kinases. The Csk-binding protein (Cbp) localizes Csk close to its substrates at the plasma membrane, and increases the specific activity of the kinase. To investigate this long-range catalytic effect, the phosphorylation of Src and the conformation of Csk were investigated in the presence of a high-affinity phosphopeptide derived from Cbp. This peptide binds tightly to the SH2 domain and enhances Src recognition (lowers K(m)) by increasing the apparent phosphoryl transfer rate in the Csk active site, a phenomenon detected in rapid quench flow experiments. Previous studies demonstrated that the regulation of Csk activity is linked to conformational changes in the enzyme that can be probed with hydrogen-deuterium exchange methods. We show that the Cbp peptide impacts deuterium incorporation into its binding partner (the SH2 domain), and into the SH2-kinase linker and several sequences in the kinase domain, including the glycine-rich loop in the active site. These findings, along with computational data from normal mode analyses, suggest that the SH2 domain moves in a cantilever fashion with respect to the small lobe of the kinase domain, ordering the active site for catalysis. The binding of a small Cbp-derived peptide to the SH2 domain of Csk modifies these motions, enhancing Src recognition.

  14. Independent motion control of a tower crane through wireless sensor and actuator networks.

    Science.gov (United States)

    Koumboulis, Fotis N; Kouvakas, Nikolaos D; Giannaris, George L; Vouyioukas, Demosthenes

    2016-01-01

    The problem of independent control of the performance variables of a tower crane through a wireless sensor and actuator network is investigated. The complete nonlinear mathematical model of the tower crane is developed. Based on appropriate data driven norms an accurate linear approximant of the system, including an upper bound of the communication delays, is derived. Using this linear approximant, a dynamic measurable output multi delay controller for independent control of the performance outputs of the system is proposed. The controller performs satisfactory despite the nonlinearities of the model and the communication delays of the wireless network. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation-Vision-Based Control for Precise Reaching Motion of Upper Limb.

    Science.gov (United States)

    Oguntosin, Victoria W; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J; Kawamura, Sadao; Hayashi, Yoshikatsu

    2017-01-01

    We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments.

  16. Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation—Vision-Based Control for Precise Reaching Motion of Upper Limb

    Science.gov (United States)

    Oguntosin, Victoria W.; Mori, Yoshiki; Kim, Hyejong; Nasuto, Slawomir J.; Kawamura, Sadao; Hayashi, Yoshikatsu

    2017-01-01

    We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM). Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments. PMID:28736514

  17. Design and Validation of Exoskeleton Actuated by Soft Modules toward Neurorehabilitation—Vision-Based Control for Precise Reaching Motion of Upper Limb

    Directory of Open Access Journals (Sweden)

    Victoria W. Oguntosin

    2017-07-01

    Full Text Available We demonstrated the design, production, and functional properties of the Exoskeleton Actuated by the Soft Modules (EAsoftM. Integrating the 3D printed exoskeleton with passive joints to compensate gravity and with active joints to rotate the shoulder and elbow joints resulted in ultra-light system that could assist planar reaching motion by using the vision-based control law. The EAsoftM can support the reaching motion with compliance realized by the soft materials and pneumatic actuation. In addition, the vision-based control law has been proposed for the precise control over the target reaching motion within the millimeter scale. Aiming at rehabilitation exercise for individuals, typically soft actuators have been developed for relatively small motions, such as grasping motion, and one of the challenges has been to extend their use for a wider range reaching motion. The proposed EAsoftM presented one possible solution for this challenge by transmitting the torque effectively along the anatomically aligned with a human body exoskeleton. The proposed integrated systems will be an ideal solution for neurorehabilitation where affordable, wearable, and portable systems are required to be customized for individuals with specific motor impairments.

  18. Velocity-dependent changes of rotational axes in the non-visual control of unconstrained 3D arm motions.

    Science.gov (United States)

    Isableu, B; Rezzoug, N; Mallet, G; Bernardin, D; Gorce, P; Pagano, C C

    2009-12-29

    We examined the roles of inertial (e(3)), shoulder-centre of mass (SH-CM) and shoulder-elbow articular (SH-EL) rotation axes in the non-visual control of unconstrained 3D arm rotations. Subjects rotated the arm in elbow configurations that yielded either a constant or variable separation between these axes. We hypothesized that increasing the motion frequency and the task complexity would result in the limbs' rotational axis to correspond to e(3) in order to minimize rotational resistances. Results showed two velocity-dependent profiles wherein the rotation axis coincided with the SH-EL axis for S and I velocities and then in the F velocity shifted to either a SH-CM/e(3) trade-off axis for one profile, or to no preferential axis for the other. A third profile was velocity-independent, with the SH-CM/e(3) trade-off axis being adopted. Our results are the first to provide evidence that the rotational axis of a multi-articulated limb may change from a geometrical axis of rotation to a mass or inertia based axis as motion frequency increases. These findings are discussed within the framework of the minimum inertia tensor model (MIT), which shows that rotations about e(3) reduce the amount of joint muscle torque that must be produced by employing the interaction torque to assist movement.

  19. Ride Control Systems - Reduced Motions on the Cost of Increased Sectional Forces ?

    DEFF Research Database (Denmark)

    Folsø, R.; Nielsen, Ulrik Dam; Torti, F.

    2003-01-01

    Implementation of passive and active ride control systems into both linear frequency and non-linear time domain strip theories is described. The ride control systems considered can consist of T-foils, fins or a combination of these. These appendages are taken into account by considering the lift...

  20. Non-Markovianity in the optimal control of an open quantum system described by hierarchical equations of motion

    Science.gov (United States)

    Mangaud, E.; Puthumpally-Joseph, R.; Sugny, D.; Meier, C.; Atabek, O.; Desouter-Lecomte, M.

    2018-04-01

    Optimal control theory is implemented with fully converged hierarchical equations of motion (HEOM) describing the time evolution of an open system density matrix strongly coupled to the bath in a spin-boson model. The populations of the two-level sub-system are taken as control objectives; namely, their revivals or exchange when switching off the field. We, in parallel, analyze how the optimal electric field consequently modifies the information back flow from the environment through different non-Markovian witnesses. Although the control field has a dipole interaction with the central sub-system only, its indirect influence on the bath collective mode dynamics is probed through HEOM auxiliary matrices, revealing a strong correlation between control and dissipation during a non-Markovian process. A heterojunction is taken as an illustrative example for modeling in a realistic way the two-level sub-system parameters and its spectral density function leading to a non-perturbative strong coupling regime with the bath. Although, due to strong system-bath couplings, control performances remain rather modest, the most important result is a noticeable increase of the non-Markovian bath response induced by the optimally driven processes.

  1. Free and Open-source Control Software for 3-D Motion and Processing

    Directory of Open Access Journals (Sweden)

    Bas Wijnen

    2016-01-01

    Full Text Available RepRap 3-D printers and their derivatives using conventional firmware are limited by: 1 requiring technical knowledge, 2 poor resilience with unreliable hardware, and 3 poor integration in complicated systems. In this paper, a new control system called Franklin, for CNC machines in general and 3-D printers specifically, is presented that enables web-based three dimensional control of additive, subtractive and analytical tools from any Internet connected device. Franklin can be set up and controlled entirely from a web interface; it uses a custom protocol which allows it to continue printing when the connection is temporarily lost, and allows communication with scripts.

  2. Motion control of planar parallel robot using the fuzzy descriptor system approach.

    Science.gov (United States)

    Vermeiren, Laurent; Dequidt, Antoine; Afroun, Mohamed; Guerra, Thierry-Marie

    2012-09-01

    This work presents the control of a two-degree of freedom parallel robot manipulator. A quasi-LPV approach, through the so-called TS fuzzy model and LMI constraints problems is used. Moreover, in this context a way to derive interesting control laws is to keep the descriptor form of the mechanical system. Therefore, new LMI problems have to be defined that helps to reduce the conservatism of the usual results. Some relaxations are also proposed to leave the pure quadratic stability/stabilization framework. A comparison study between the classical control strategies from robotics and the control design using TS fuzzy descriptor models is carried out to show the interest of the proposed approach. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  3. Motion Sensorless Control of BLDC PM Motor with Offline FEM Info Assisted State Observer

    DEFF Research Database (Denmark)

    Stirban, Alin; Boldea, Ion; Andreescu, Gheorghe-Daniel

    2010-01-01

    This paper describes a new offline FEM assisted position and speed observer, for brushless dc (BLDC) PM motor drive sensorless control, based on the line-to-line PM flux linkage estimation. The zero-crossing of the line-to-line PM flux linkage occurs right in the middle of two commutation points...... identification. Digital simulations and experimental results are shown, demonstrating the reliability of the FEM assisted position and speed observer for BLDC PM motor sensorless control operation....

  4. Foreword(Advances in Motion and Vibration Control Technology)

    OpenAIRE

    水野, 毅

    2003-01-01

    A new vibration isolation system using negative stiffness realized by active control technique is proposed in this paper. The serial connection of a normal spring and a suspension system with negative stiffness enables the isolation system to have low stiffness for vibration from the ground and high (theoretically infinite) stiffness against direct disturbance acting on the isolation table. A control method of realizing negative stiffness with a linear actuator is presented in an analytical f...

  5. A sub-target approach to the kinodynamic motion control of a wheeled mobile robot

    Science.gov (United States)

    Motonaka, Kimiko; Watanabe, Keigo; Maeyama, Shoichi

    2018-02-01

    A mobile robot with two independently driven wheels is popular, but it is difficult to stabilize it by a continuous controller with a constant gain, due to its nonholonomic property. It is guaranteed that a nonholonomic controlled object can always be converged to an arbitrary point using a switching control method or a quasi-continuous control method based on an invariant manifold in a chained form. From this, the authors already proposed a kinodynamic controller to converge the states of such a two-wheeled mobile robot to the arbitrary target position while avoiding obstacles, by combining the control based on the invariant manifold and the harmonic potential field (HPF). On the other hand, it was confirmed in the previous research that there is a case that the robot cannot avoid the obstacle because there is no enough space to converge the current state to the target state. In this paper, we propose a method that divides the final target position into some sub-target positions and moves the robot step by step, and it is confirmed by the simulation that the robot can converge to the target position while avoiding obstacles using the proposed method.

  6. Demonstration of motion control of ZrO2 microparticles in uniform/non-uniform electric field

    Science.gov (United States)

    Onishi, Genki; Trung, Ngo Nguyen Chi; Matsutani, Naoto; Nakayama, Tadachika; Suzuki, Tsuneo; Suematsu, Hisayuki; Niihara, Koichi

    2018-02-01

    This study aims to elucidate the mechanism that drives dielectric microparticles under an electric field. The driving of microstructures is affected by various electrical phenomena occurring at the same time such as surface potential, polarization, and electrostatic force. It makes the clarification of the driving mechanism challenging. A simple experimental system was used to observe the behavior of spherical ZrO2 microparticles in a nonaqueous solution under an electric field. The results suggest that the mechanism that drives the ZrO2 microparticles under an electric field involved the combination of an electric image force, a gradient force, and the contact charging phenomenon. A method is proposed to control the motion of micro- and nanostructures in further study and applications.

  7. Microcontroller based motion control interface unit for double slit type beam emittance monitor for H- ion source

    International Nuclear Information System (INIS)

    Holikatti, A.C.; Jain, Rahul; Karnewar, A.K.; Sonawane, B.B.; Maurya, N.K.; Puntambekar, T.A.

    2015-01-01

    The Indian Spallation Neutron Source (ISNS), proposed to be developed at RRCAT, will use a 1 GeV H - linac and an accumulator ring to produce high flux of pulsed neutrons via spallation process. The development activity of front end of 1H - linac for ISNS is under progress at RRCAT, for which a pulsed H - ion source of 50 keV energy, 30 mA current with pulse width of 500 μs has been developed at RRCAT. In this paper, we present the design and development of a microcontroller based motion control interface unit for double slit type beam emittance monitor for the H - ion source. This is an interceptive type of beam diagnostic device, which is used for the quantitative measurement of transverse emittance and beam intensity profile

  8. Identifying postural control and thresholds of instability utilizing a motion-based ATV simulator.

    Science.gov (United States)

    2017-01-01

    Our ATV simulator is currently the only one in existence that allows studies of human subjects engaged in active riding, a process that is necessary for ATV operators to perform in order to maintain vehicle control, in a virtual reality environ...

  9. Attitude Control of Nanosatellites by Paddle Motion Using Elastic Hinges Actuated by Shape Memory Alloy

    Science.gov (United States)

    Iai, Masafumi; Durali, Mohammad; Hatsuzawa, Takeshi

    Recent research has been extending the applications of small satellites called microsatellites, nanosatellites, or picosatellites. To further improve capability of those satellites, a lightweight, active attitude-control mechanism is needed. This paper proposes a concept of inertial orientation control, an attitude control method using movable solar arrays. This method is made suitable for nanosatellites by the use of shape memory alloy (SMA)-actuated elastic hinges and a simple maneuver generation algorithm. The combination of SMA and an elastic hinge allows the hinge to remain lightweight and free of frictional or rolling contacts. Changes in the shrinking and stretching speeds of the SMA were measured in a vacuum chamber. The proposed algorithm constructs a maneuver to achieve arbitrary attitude change by repeating simple maneuvers called unit maneuvers. Provided with three types of unit maneuvers, each degree of freedom of the satellite can be controlled independently. Such construction requires only simple calculations, making it a practical algorithm for a nanosatellite with limited computational capability. In addition, power generation variation caused by maneuvers was analyzed to confirm that a maneuver from any initial attitude to an attitude facing the sun was justifiable in terms of the power budget.

  10. Single motor–variable stiffness actuator using bistable switching mechanisms for independent motion and stiffness control

    NARCIS (Netherlands)

    Groothuis, Stefan; Carloni, Raffaella; Stramigioli, Stefano

    This paper presents a proof of concept of a variable stiffness actuator (VSA) that uses only one (high power) input motor. In general, VSAs use two (high power) motors to be able to control both the output position and the output stiffness, which possibly results in a heavy, and bulky system. In

  11. Grid to Standalone Transition Motion-Sensorless Dual-Inverter Control of PMSG With Asymmetrical Grid Voltage Sags and Harmonics Filtering

    DEFF Research Database (Denmark)

    Fatu, M.; Blaabjerg, Frede; Boldea, I.

    2014-01-01

    This paper describes a variable-speed motion-sensorless control system for permanent-magnet synchronous generator (PMSG) connected to grid via back-to-back inverters for wind energy generation. The grid-side inverter control system employs proportional-integral (PI) current controllers with cross...... and automatic seamless transfer method from grid connected to stand alone and vice versa. In stand-alone mode, a voltage control scheme with selective harmonic compensation is employed. The PMSG motion-sensorless control system uses an active power controller and a PLL-based observer to estimate the rotor...... and voltage harmonics compensation. While some of the aforementioned issues have been treated rather individually in previous conference publications of the authors, the present paper integrates them into a comprehensive control system of PMSG....

  12. Optimising UAV topographic surveys processed with structure-from-motion: Ground control quality, quantity and bundle adjustment

    Science.gov (United States)

    James, Mike R.; Robson, Stuart; d'Oleire-Oltmanns, Sebastian; Niethammer, Uwe

    2016-04-01

    Structure-from-motion (SfM) algorithms are greatly facilitating the production of detailed topographic models based on images collected by unmanned aerial vehicles (UAVs). However, SfM-based software does not generally provide the rigorous photogrammetric analysis required to fully understand survey quality. Consequently, error related to problems in control point data or the distribution of control points can remain undiscovered. Even if these errors are not large in magnitude, they can be systematic, and thus have strong implications for the use of products such as digital elevation models (DEMs) and orthophotos. Here, we develop a Monte Carlo approach to (1) improve the accuracy of products when SfM-based processing is used and (2) reduce the associated field effort by identifying suitable lower density deployments of ground control points. The method highlights over-parameterisation during camera self-calibration and provides enhanced insight into control point performance when rigorous error metrics are not available. Processing was implemented using commonly-used SfM-based software (Agisoft PhotoScan), which we augment with semi-automated and automated GCPs image measurement. We apply the Monte Carlo method to two contrasting case studies - an erosion gully survey (Taurodont, Morocco) carried out with an fixed-wing UAV, and an active landslide survey (Super-Sauze, France), acquired using a manually controlled quadcopter. The results highlight the differences in the control requirements for the two sites, and we explore the implications for future surveys. We illustrate DEM sensitivity to critical processing parameters and show how the use of appropriate parameter values increases DEM repeatability and reduces the spatial variability of error due to processing artefacts.

  13. Fuzzy control with random delays using invariant cones and its application to control of energy processes in microelectromechanical motion devices

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A.S.C. [Purdue Univ., Indianapolis, IN (United States). Dept. of Electrical Engineering; Lyshevski, S. [Rochester Inst. of Technology, NY (United States)

    2005-05-01

    In this paper, a class of microelectromechanical systems described by nonlinear differential equations with random delays is examined. Robust fuzzy controllers are designed to control the energy conversion processes with the ultimate objective to guarantee optimal achievable performance. The fuzzy rule base used consists of a collection of r fuzzy IF-THEN rules defined as a function of the conditional variable. The method of the theory of cones and Lyapunov functionals is used to design a class of local fuzzy control laws. A verifiably sufficient condition for stochastic stability of fuzzy stochastic microelectromechanical systems is given. As an example, we have considered the design of a fuzzy control law for an electrostatic micromotor. (author)

  14. Fuzzy control with random delays using invariant cones and its application to control of energy processes in microelectromechanical motion devices

    International Nuclear Information System (INIS)

    Sinha, A.S.C.; Lyshevski, S.

    2005-01-01

    In this paper, a class of microelectromechanical systems described by nonlinear differential equations with random delays is examined. Robust fuzzy controllers are designed to control the energy conversion processes with the ultimate objective to guarantee optimal achievable performance. The fuzzy rule base used consists of a collection of r fuzzy IF-THEN rules defined as a function of the conditional variable. The method of the theory of cones and Lyapunov functionals is used to design a class of local fuzzy control laws. A verifiably sufficient condition for stochastic stability of fuzzy stochastic microelectromechanical systems is given. As an example, we have considered the design of a fuzzy control law for an electrostatic micromotor

  15. The accuracy of webcams in 2D motion analysis: sources of error and their control

    International Nuclear Information System (INIS)

    Page, A; Candelas, P; Belmar, F; Moreno, R

    2008-01-01

    In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost

  16. The accuracy of webcams in 2D motion analysis: sources of error and their control

    Energy Technology Data Exchange (ETDEWEB)

    Page, A; Candelas, P; Belmar, F [Departamento de Fisica Aplicada, Universidad Politecnica de Valencia, Valencia (Spain); Moreno, R [Instituto de Biomecanica de Valencia, Valencia (Spain)], E-mail: alvaro.page@ibv.upv.es

    2008-07-15

    In this paper, we show the potential of webcams as precision measuring instruments in a physics laboratory. Various sources of error appearing in 2D coordinate measurements using low-cost commercial webcams are discussed, quantifying their impact on accuracy and precision, and simple procedures to control these sources of error are presented. Finally, an experiment with controlled movement is performed to experimentally measure the errors described above and to assess the effectiveness of the proposed corrective measures. It will be shown that when these aspects are considered, it is possible to obtain errors lower than 0.1%. This level of accuracy demonstrates that webcams should be considered as very precise and accurate measuring instruments at a remarkably low cost.

  17. Modeling light-field-controlled electron motion in atoms and solids

    OpenAIRE

    Korbman, Michael

    2012-01-01

    Recent advancements in laser technology are quickly moving the frontiers of research: quantum dynamics can now be investigated in more detail, on new timescales, with an unprecedented level of control. These new possibilities offer a new ground for the theoretical study of fundamental processes; at the same time, a proper understanding of phenomena involved is necessary to explain measurements, and to indicate directions for further experiments. This Thesis deals with the theoretical...

  18. IT-Tools Concept for Simulation and Design of Water Hydraulic Mechatronic Test Facilities for Motion Control and Operation in Environmentally Sensitive Application Areas

    DEFF Research Database (Denmark)

    Conrad, Finn; Pobedza, J.; Sobczyk, A.

    2004-01-01

    This paper presents a proposed IT-Tools concept for modeling, simulation, analysis and design of water hydraulic actuators for motion control of machines, lifts, cranes and robots. The designed test rigs have tap water hydraulic components of the Danfoss Nessie® product family and equipped...... with a measurement and data acquisition system. Results of the mathematical modeling, simulation and design of the motion control test rigs are presented. Furthermore, the paper presents selected experimental and identifying test results for the water hydraulic test rigs....

  19. Absolute Plate Motion Control Since the Triassic from the Cocos Slab and its Associated Subduction Record in Mexico

    Science.gov (United States)

    Boschman, L.; Van Hinsbergen, D. J. J.; Langereis, C. G.; Molina-Garza, R. S.; Kimbrough, D. L.; Spakman, W.

    2017-12-01

    A positive wave speed anomaly interpreted as the Cocos slab stretches from the uppermost mantle at the Middle America trench in the west, to the lowermost mantle below the Atlantic in the east. The length and continuity of this slab indicates long-lived, uninterrupted eastward subduction of the attached Cocos Plate and its predecessor, the Farallon Plate. The geological record of Mexico contains Triassic to present day evidence of subduction, of which the post-Late Cretaceous phase is of continental margin-style. Interpretations of the pre-Upper Cretaceous subduction-related rock assemblages are under debate, and vary from far-travelled exotic intra-oceanic island arc character to in-situ extended continental margin origin. We present new paleomagnetic data that show that Triassic, Jurassic and Cretaceous subduction-related rocks from the Vizcaíno Peninsula and the Guerrero terrane have a paleolatitudinal plate motion history that is equal to that of the North American continent. This suggests that these rock assemblages were part of the overriding plate and were perhaps only separated from the North American continent by temporal fore- or back-arc spreading. The entire Triassic-present day subduction record, and hence, reconstructed trench location, can therefore be linked to the Cocos slab, which provides control on longitudinal plate motion of North America since the time of Pangea. Compared to the latest state of the art mantle frames, in which longitudes are essentially unconstrained for pre-Cretaceous times, our reconstructed absolute position of North America requires a significant westward longitudinal shift for Mesozoic times.

  20. Chaos in balance: non-linear measures of postural control predict individual variations in visual illusions of motion.

    Directory of Open Access Journals (Sweden)

    Deborah Apthorp

    Full Text Available Visually-induced illusions of self-motion (vection can be compelling for some people, but they are subject to large individual variations in strength. Do these variations depend, at least in part, on the extent to which people rely on vision to maintain their postural stability? We investigated by comparing physical posture measures to subjective vection ratings. Using a Bertec balance plate in a brightly-lit room, we measured 13 participants' excursions of the centre of foot pressure (CoP over a 60-second period with eyes open and with eyes closed during quiet stance. Subsequently, we collected vection strength ratings for large optic flow displays while seated, using both verbal ratings and online throttle measures. We also collected measures of postural sway (changes in anterior-posterior CoP in response to the same visual motion stimuli while standing on the plate. The magnitude of standing sway in response to expanding optic flow (in comparison to blank fixation periods was predictive of both verbal and throttle measures for seated vection. In addition, the ratio between eyes-open and eyes-closed CoP excursions during quiet stance (using the area of postural sway significantly predicted seated vection for both measures. Interestingly, these relationships were weaker for contracting optic flow displays, though these produced both stronger vection and more sway. Next we used a non-linear analysis (recurrence quantification analysis, RQA of the fluctuations in anterior-posterior position during quiet stance (both with eyes closed and eyes open; this was a much stronger predictor of seated vection for both expanding and contracting stimuli. Given the complex multisensory integration involved in postural control, our study adds to the growing evidence that non-linear measures drawn from complexity theory may provide a more informative measure of postural sway than the conventional linear measures.