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Sample records for force control multi

  1. Multi-muscle FES force control of the human arm for arbitrary goals.

    Science.gov (United States)

    Schearer, Eric M; Liao, Yu-Wei; Perreault, Eric J; Tresch, Matthew C; Memberg, William D; Kirsch, Robert F; Lynch, Kevin M

    2014-05-01

    We present a method for controlling a neuroprosthesis for a paralyzed human arm using functional electrical stimulation (FES) and characterize the errors of the controller. The subject has surgically implanted electrodes for stimulating muscles in her shoulder and arm. Using input/output data, a model mapping muscle stimulations to isometric endpoint forces measured at the subject's hand was identified. We inverted the model of this redundant and coupled multiple-input multiple-output system by minimizing muscle activations and used this inverse for feedforward control. The magnitude of the total root mean square error over a grid in the volume of achievable isometric endpoint force targets was 11% of the total range of achievable forces. Major sources of error were random error due to trial-to-trial variability and model bias due to nonstationary system properties. Because the muscles working collectively are the actuators of the skeletal system, the quantification of errors in force control guides designs of motion controllers for multi-joint, multi-muscle FES systems that can achieve arbitrary goals.

  2. Force Control and Nonlinear Master-Slave Force Profile to Manage an Admittance Type Multi-Fingered Haptic User Interface

    Energy Technology Data Exchange (ETDEWEB)

    Anthony L. Crawford

    2012-08-01

    Natural movements and force feedback are important elements in using teleoperated equipment if complex and speedy manipulation tasks are to be accomplished in remote and/or hazardous environments, such as hot cells, glove boxes, decommissioning, explosives disarmament, and space to name a few. In order to achieve this end the research presented in this paper has developed an admittance type exoskeleton like multi-fingered haptic hand user interface that secures the user’s palm and provides 3-dimensional force feedback to the user’s fingertips. Atypical to conventional haptic hand user interfaces that limit themselves to integrating the human hand’s characteristics just into the system’s mechanical design this system also perpetuates that inspiration into the designed user interface’s controller. This is achieved by manifesting the property differences of manipulation and grasping activities as they pertain to the human hand into a nonlinear master-slave force relationship. The results presented in this paper show that the admittance-type system has sufficient bandwidth that it appears nearly transparent to the user when the user is in free motion and when the system is subjected to a manipulation task, increased performance is achieved using the nonlinear force relationship compared to the traditional linear scaling techniques implemented in the vast majority of systems.

  3. On Optimizing Steering Performance of Multi-axle Vehicle Based on Driving Force Control

    Directory of Open Access Journals (Sweden)

    Wu Zhicheng

    2017-01-01

    Full Text Available The steering performance of multi-axle vehicle with independent driving system is affected by the distribution of the wheel driving force. A nonlinear vehicle dynamics model including magic formula tire model for describing 11 DoF four-axle vehicle with dual-front-axle-steering (DFAS system was presented. The influence of different driving force distribution scheme on the steering performance of the vehicle was analyzed. A control strategy for improving the steady response and transient response of the vehicle steering is proposed. The results show: For the steady response, setting different drive force for internal and external wheels according to the actual steering characteristics of the vehicle can effectively improve its steering characteristics; For the transient response, adopting the zero sideslip angle control strategy and using the PID control algorithm to control the driving force of the outside wheel of tear-two-axle, under angle step input, the vehicle sideslip angle can quickly stabilize to 0 and yaw rate also significantly decreases.

  4. Damping-controlled fluidelastic instability forces in multi-span tubes with loose supports

    International Nuclear Information System (INIS)

    Hassan, Marwan A.; Rogers, Robert J.; Gerber, Andrew G.

    2011-01-01

    This paper presents simulations of a loosely supported multi-span tube subjected to turbulence and fluidelastic instability forces in order to compare several time-domain fluid force models simulating the damping-controlled fluidelastic instability mechanism in tube arrays. These models include the negative damping model based on the Connors equation, fluid force coefficient-based models (Chen; Tanaka and Takahara), and two semi-analytical models (Price and Paidoussis; and Lever and Weaver). Time domain modelling challenges for each of these theories are discussed. The implemented models are validated against available experimental data. The linear simulations (without tube/support clearance) show that the Connors-equation based model exhibits the most conservative prediction of the critical flow velocity when the recommended design values for the Connors equation are used. The models are then utilized to simulate the nonlinear response of a three-span cantilever tube in a lattice bar support subjected to air crossflow. The tube is subjected to a single-phase flow passing over the spans where the flow velocity and the support clearance are varied. Special attention is paid to the tube/support interaction parameters that affect wear, such as impact forces, contact ratio, and normal work rate. As was seen for the linear cases, the reduced flow velocity at the instability threshold differs for the fluid force models considered. The investigated models do, however, exhibit similar response characteristics for the impact force, tip lift response, and work rate, except for the Connors-based model that overestimates the response and the tube/support interaction parameters for the loose support case, especially at large clearances.

  5. Multi-layered controllable stiffness beams for morphing: energy, actuation force, and material strain considerations

    International Nuclear Information System (INIS)

    Murray, Gabriel; Gandhi, Farhan

    2010-01-01

    Morphing aerospace structures could benefit from the ability of structural elements to transition from a stiff load-bearing state to a relatively compliant state that can undergo large deformation at low actuation cost. The present paper focuses on multi-layered beams with controllable flexural stiffness—comprising polymer layers affixed to the surfaces of a base beam and cover layers, in turn, affixed to the surfaces of the polymer layers. Heating the polymer through the glass transition reduces its shear modulus, decouples the cover layers from the base beam and reduces the overall flexural stiffness. Although the stiffness and actuation force required to bend the beam reduce, the energy required to heat the polymer layer must also be considered. Results show that for beams with low slenderness ratios, relatively thick polymer layers, and cover layers whose extensional stiffness is high, the decoupling of the cover layers through softening of the polymer layers can result in flexural stiffness reductions of over 95%. The energy savings are also highest for these configurations, and will increase as the deformation of the beam increases. The decoupling of the cover layers from the base beam through the softening of the polymer reduces the axial strains in the cover layers significantly; otherwise material failure would prevent large deformation. Results show that when the polymer layer is stiff, the cover layers are the dominant contributors to the total energy in the beam, and the energy in the polymer layers is predominantly axial strain energy. When the polymer layers are softened the energy in the cover layers is a small contributor to the total energy which is dominated by energy in the base beam and shear strain energy in the polymer layer

  6. The constrained control of force and position in multi-joint movements.

    Science.gov (United States)

    van Ingen Schenau, G J; Boots, P J; de Groot, G; Snackers, R J; van Woensel, W W

    1992-01-01

    In many arm or leg movements the hand or foot has to exert an external force on the environment. Based on an inverse dynamical analysis of cycling, it is shown that the distribution of net moments in the joints needed to control the direction of the external force is often opposite to the direction of joint displacements associated with this task. Kinetic and kinematic data were obtained from five experienced cyclists during ergometer cycling by means of film analysis and pedal force measurement. An inverse dynamic analysis, based on a linked segments model, yielded net joint moments, joint powers and muscle shortening velocities of eight leg muscles. Activation patterns of the muscles were obtained by means of surface electromyography. The results show that the transfer of rotations in hip, knee and ankle joints into the translation of the pedal is constrained by conflicting requirements. This occurs between the joint moments necessary to contribute to joint power and the moments necessary to establish a direction of the force on the pedal which allows this force to do work on the pedal. Co-activation of mono-articular agonists and their bi-articular antagonists appear to provide a unique solution for these conflicting requirements: bi-articular muscles appear to be able to control the desired direction of the external force on the pedal by adjusting the relative distribution of net moments over the joints while mono-articular muscles appear to be primarily activated when they are in the position to shorten and thus to contribute to positive work. Examples are given to illustrate the universal nature of this constrained control of force (external) and position (joint). Based on this study and published data it is suggested that different processes may underlie the organization of the control of mono- and bi-articular muscles.

  7. Design and control of multi-actuated atomic force microscope for large-range and high-speed imaging

    Energy Technology Data Exchange (ETDEWEB)

    Soltani Bozchalooi, I.; Careaga Houck, A. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); AlGhamdi, J. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Department of Chemistry, College of Science, University of Dammam, Dammam (Saudi Arabia); Youcef-Toumi, K. [Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)

    2016-01-15

    This paper presents the design and control of a high-speed and large-range atomic force microscopy (AFM). A multi-actuation scheme is proposed where several nano-positioners cooperate to achieve the range and speed requirements. A simple data-based control design methodology is presented to effectively operate the AFM scanner components. The proposed controllers compensate for the coupled dynamics and divide the positioning responsibilities between the scanner components. As a result, the multi-actuated scanner behavior is equivalent to that of a single X–Y–Z positioner with large range and high speed. The scanner of the designed AFM is composed of five nano-positioners, features 6 μm out-of-plane and 120 μm lateral ranges and is capable of high-speed operation. The presented AFM has a modular design with laser spot size of 3.5 μm suitable for small cantilever, an optical view of the sample and probe, a conveniently large waterproof sample stage and a 20 MHz data throughput for high resolution image acquisition at high imaging speeds. This AFM is used to visualize etching of calcite in a solution of sulfuric acid. Layer-by-layer dissolution and pit formation along the crystalline lines in a low pH environment is observed in real time. - Highlights: • High-speed AFM imaging is extended to large lateral and vertical scan ranges. • A general multi-actuation approach to atomic force microscopy is presented. • A high-speed AFM is designed and implemented based on the proposed method. • Multi-actuator control is designed auxiliary to a PID unit to maintain flexibility. • Influence of calcite crystal structure on dissolution is visualized in video form.

  8. Time domain models for damping-controlled fluidelastic instability forces in multi-span tubes with loose supports

    International Nuclear Information System (INIS)

    Hassan, M.A.; Rogers, R.J.; Gerber, A.G.

    2009-01-01

    This paper presents simulations of a loosely supported multi-span tube subjected to turbulence and fluidelastic instability forces. Several time-domain fluid force models simulating the damping controlled fluidelastic instability mechanism in tube arrays have been presented. These models include the negative damping model based on the Connors equation, fluid force coefficient-based models (Chen and Tanaka and Takahara), and two semi-analytical models (Price and Paidoussis; and Lever and Weaver) were implemented in an in-house finite code. Time domain modeling challenges for each of these theories were discussed. The implemented models were validated against available experimental data. The linear simulations showed that the Connors-equation based model exhibits the most conservative prediction of the critical flow velocity when the recommended design values for the Connors equation were used. The models were then utilized to simulate the nonlinear response of a three-span cantilever tube in a square lattice bar support subjected to air crossflow. The tube was subjected to a single-phase flow passing over one of the tube's spans. For each of these models the flow velocity and the support clearance were varied. Special attention was paid to the tube/support interaction parameters that affect wear, such as impact forces, contact ratio, and normal work rate. As the prediction of the linear threshold varies depending on the utilized model, the nonlinear response also differs. The investigated models exhibit similar response characteristics for the impact force, tip lift response, and work rate. Simulation results show that the Connors-based model underestimates the response and the tube/support interaction parameters for the loose support case. (author)

  9. Multi-actuation and PI control: A simple recipe for high-speed and large-range atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Soltani Bozchalooi, I., E-mail: isoltani@mit.edu; Youcef-Toumi, K.

    2014-11-15

    High speed atomic force microscopy enables observation of dynamic nano-scale processes. However, maintaining a minimal interaction force between the sample and the probe is challenging at high speed specially when using conventional piezo-tubes. While rigid AFM scanners are operational at high speeds with the drawback of reduced tracking range, multi-actuation schemes have shown potential for high-speed and large-range imaging. Here we present a method to seamlessly incorporate additional actuators into conventional AFMs. The equivalent behavior of the resulting multi-actuated setup resembles that of a single high-speed and large-range actuator with maximally flat frequency response. To achieve this, the dynamics of the individual actuators and their couplings are treated through a simple control scheme. Upon the implementation of the proposed technique, commonly used PI controllers are able to meet the requirements of high-speed imaging. This forms an ideal platform for retroactive enhancement of existing AFMs with minimal cost and without compromise on the tracking range. A conventional AFM with tube scanner is retroactively enhanced through the proposed method and shows an order of magnitude improvement in closed loop bandwidth performance while maintaining large range. The effectiveness of the method is demonstrated on various types of samples imaged in contact and tapping modes, in air and in liquid. - Highlights: • We present a novel method to incorporate extra actuators into conventional AFMs. • A maximally flat frequency response is achieved for the out of plane piezo-motion. • Commonly used PI or PID control is enabled to handle high speed AFM imaging. • An order of magnitude improvement in closed loop bandwidth performance is obtained. • High speed imaging is achieved on a large range piezo-tube.

  10. Multi-actuation and PI control: A simple recipe for high-speed and large-range atomic force microscopy

    International Nuclear Information System (INIS)

    Soltani Bozchalooi, I.; Youcef-Toumi, K.

    2014-01-01

    High speed atomic force microscopy enables observation of dynamic nano-scale processes. However, maintaining a minimal interaction force between the sample and the probe is challenging at high speed specially when using conventional piezo-tubes. While rigid AFM scanners are operational at high speeds with the drawback of reduced tracking range, multi-actuation schemes have shown potential for high-speed and large-range imaging. Here we present a method to seamlessly incorporate additional actuators into conventional AFMs. The equivalent behavior of the resulting multi-actuated setup resembles that of a single high-speed and large-range actuator with maximally flat frequency response. To achieve this, the dynamics of the individual actuators and their couplings are treated through a simple control scheme. Upon the implementation of the proposed technique, commonly used PI controllers are able to meet the requirements of high-speed imaging. This forms an ideal platform for retroactive enhancement of existing AFMs with minimal cost and without compromise on the tracking range. A conventional AFM with tube scanner is retroactively enhanced through the proposed method and shows an order of magnitude improvement in closed loop bandwidth performance while maintaining large range. The effectiveness of the method is demonstrated on various types of samples imaged in contact and tapping modes, in air and in liquid. - Highlights: • We present a novel method to incorporate extra actuators into conventional AFMs. • A maximally flat frequency response is achieved for the out of plane piezo-motion. • Commonly used PI or PID control is enabled to handle high speed AFM imaging. • An order of magnitude improvement in closed loop bandwidth performance is obtained. • High speed imaging is achieved on a large range piezo-tube

  11. Design and implementation of a novel modal space active force control concept for spatial multi-DOF parallel robotic manipulators actuated by electrical actuators.

    Science.gov (United States)

    Yang, Chifu; Zhao, Jinsong; Li, Liyi; Agrawal, Sunil K

    2018-01-01

    Robotic spine brace based on parallel-actuated robotic system is a new device for treatment and sensing of scoliosis, however, the strong dynamic coupling and anisotropy problem of parallel manipulators result in accuracy loss of rehabilitation force control, including big error in direction and value of force. A novel active force control strategy named modal space force control is proposed to solve these problems. Considering the electrical driven system and contact environment, the mathematical model of spatial parallel manipulator is built. The strong dynamic coupling problem in force field is described via experiments as well as the anisotropy problem of work space of parallel manipulators. The effects of dynamic coupling on control design and performances are discussed, and the influences of anisotropy on accuracy are also addressed. With mass/inertia matrix and stiffness matrix of parallel manipulators, a modal matrix can be calculated by using eigenvalue decomposition. Making use of the orthogonality of modal matrix with mass matrix of parallel manipulators, the strong coupled dynamic equations expressed in work space or joint space of parallel manipulator may be transformed into decoupled equations formulated in modal space. According to this property, each force control channel is independent of others in the modal space, thus we proposed modal space force control concept which means the force controller is designed in modal space. A modal space active force control is designed and implemented with only a simple PID controller employed as exampled control method to show the differences, uniqueness, and benefits of modal space force control. Simulation and experimental results show that the proposed modal space force control concept can effectively overcome the effects of the strong dynamic coupling and anisotropy problem in the physical space, and modal space force control is thus a very useful control framework, which is better than the current joint

  12. Anticipatory synergy adjustments reflect individual performance of feedforward force control.

    Science.gov (United States)

    Togo, Shunta; Imamizu, Hiroshi

    2016-10-06

    We grasp and dexterously manipulate an object through multi-digit synergy. In the framework of the uncontrolled manifold (UCM) hypothesis, multi-digit synergy is defined as the coordinated control mechanism of fingers to stabilize variable important for task success, e.g., total force. Previous studies reported anticipatory synergy adjustments (ASAs) that correspond to a drop of the synergy index before a quick change of the total force. The present study compared ASA's properties with individual performances of feedforward force control to investigate a relationship of those. Subjects performed a total finger force production task that consisted of a phase in which subjects tracked target line with visual information and a phase in which subjects produced total force pulse without visual information. We quantified their multi-digit synergy through UCM analysis and observed significant ASAs before producing total force pulse. The time of the ASA initiation and the magnitude of the drop of the synergy index were significantly correlated with the error of force pulse, but not with the tracking error. Almost all subjects showed a significant increase of the variance that affected the total force. Our study directly showed that ASA reflects the individual performance of feedforward force control independently of target-tracking performance and suggests that the multi-digit synergy was weakened to adjust the multi-digit movements based on a prediction error so as to reduce the future error. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Automated force controller for amplitude modulation atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Atsushi, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr; Scheuring, Simon, E-mail: atsushi.miyagi@inserm.fr, E-mail: simon.scheuring@inserm.fr [U1006 INSERM, Université Aix-Marseille, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, 13009 Marseille (France)

    2016-05-15

    Atomic Force Microscopy (AFM) is widely used in physics, chemistry, and biology to analyze the topography of a sample at nanometer resolution. Controlling precisely the force applied by the AFM tip to the sample is a prerequisite for faithful and reproducible imaging. In amplitude modulation (oscillating) mode AFM, the applied force depends on the free and the setpoint amplitudes of the cantilever oscillation. Therefore, for keeping the applied force constant, not only the setpoint amplitude but also the free amplitude must be kept constant. While the AFM user defines the setpoint amplitude, the free amplitude is typically subject to uncontrollable drift, and hence, unfortunately, the real applied force is permanently drifting during an experiment. This is particularly harmful in biological sciences where increased force destroys the soft biological matter. Here, we have developed a strategy and an electronic circuit that analyzes permanently the free amplitude of oscillation and readjusts the excitation to maintain the free amplitude constant. As a consequence, the real applied force is permanently and automatically controlled with picoNewton precision. With this circuit associated to a high-speed AFM, we illustrate the power of the development through imaging over long-duration and at various forces. The development is applicable for all AFMs and will widen the applicability of AFM to a larger range of samples and to a larger range of (non-specialist) users. Furthermore, from controlled force imaging experiments, the interaction strength between biomolecules can be analyzed.

  14. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator.

    Science.gov (United States)

    Raabe, D; Harrison, A; Ireland, A; Alemzadeh, K; Sandy, J; Dogramadzi, S; Melhuish, C; Burgess, S

    2012-03-01

    This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures such as posterior teeth and the two temporomandibular joints, moves with up to 6 degrees of freedom (DOF) in Cartesian space. The currently available wear simulators lack the ability to perform these chewing movements. In many cases, their lack of sufficient DOF enables them only to replicate the sliding motion of a single occlusal contact point by neglecting rotational movements and the motion along one Cartesian axis. The motion and forces of more than one occlusal contact points cannot accurately be replicated by these instruments. Furthermore, the majority of wear simulators are unable to control simultaneously the main wear-affecting parameters, considering abrasive mechanical wear, which are the occlusal sliding motion and bite forces in the constraint contact phase of the human chewing cycle. It has been shown that such discrepancies between the true in vivo and the simulated in vitro condition influence the outcome and the quality of wear studies. This can be improved by implementing biological features of the human masticatory system such as tooth compliance realized through the passive action of the periodontal ligament and active bite force control realized though the central nervous system using feedback from periodontal preceptors. The simulator described in this paper can be used for single- and multi-occlusal contact testing due to its kinematics and ability to exactly replicate human translational and rotational mandibular movements with up to 6 DOF without neglecting movements along or around the three Cartesian axes. Recorded human mandibular motion and occlusal force data are the reference inputs of the simulator

  15. Improved single- and multi-contact life-time testing of dental restorative materials using key characteristics of the human masticatory system and a force/position-controlled robotic dental wear simulator

    International Nuclear Information System (INIS)

    Raabe, D; Dogramadzi, S; Melhuish, C; Harrison, A; Alemzadeh, K; Burgess, S; Ireland, A; Sandy, J

    2012-01-01

    This paper presents a new in vitro wear simulator based on spatial parallel kinematics and a biologically inspired implicit force/position hybrid controller to replicate chewing movements and dental wear formations on dental components, such as crowns, bridges or a full set of teeth. The human mandible, guided by passive structures such as posterior teeth and the two temporomandibular joints, moves with up to 6 degrees of freedom (DOF) in Cartesian space. The currently available wear simulators lack the ability to perform these chewing movements. In many cases, their lack of sufficient DOF enables them only to replicate the sliding motion of a single occlusal contact point by neglecting rotational movements and the motion along one Cartesian axis. The motion and forces of more than one occlusal contact points cannot accurately be replicated by these instruments. Furthermore, the majority of wear simulators are unable to control simultaneously the main wear-affecting parameters, considering abrasive mechanical wear, which are the occlusal sliding motion and bite forces in the constraint contact phase of the human chewing cycle. It has been shown that such discrepancies between the true in vivo and the simulated in vitro condition influence the outcome and the quality of wear studies. This can be improved by implementing biological features of the human masticatory system such as tooth compliance realized through the passive action of the periodontal ligament and active bite force control realized though the central nervous system using feedback from periodontal preceptors. The simulator described in this paper can be used for single- and multi-occlusal contact testing due to its kinematics and ability to exactly replicate human translational and rotational mandibular movements with up to 6 DOF without neglecting movements along or around the three Cartesian axes. Recorded human mandibular motion and occlusal force data are the reference inputs of the simulator

  16. Methods and Research for Multi-Component Cutting Force Sensing Devices and Approaches in Machining

    Directory of Open Access Journals (Sweden)

    Qiaokang Liang

    2016-11-01

    Full Text Available Multi-component cutting force sensing systems in manufacturing processes applied to cutting tools are gradually becoming the most significant monitoring indicator. Their signals have been extensively applied to evaluate the machinability of workpiece materials, predict cutter breakage, estimate cutting tool wear, control machine tool chatter, determine stable machining parameters, and improve surface finish. Robust and effective sensing systems with capability of monitoring the cutting force in machine operations in real time are crucial for realizing the full potential of cutting capabilities of computer numerically controlled (CNC tools. The main objective of this paper is to present a brief review of the existing achievements in the field of multi-component cutting force sensing systems in modern manufacturing.

  17. Methods and Research for Multi-Component Cutting Force Sensing Devices and Approaches in Machining.

    Science.gov (United States)

    Liang, Qiaokang; Zhang, Dan; Wu, Wanneng; Zou, Kunlin

    2016-11-16

    Multi-component cutting force sensing systems in manufacturing processes applied to cutting tools are gradually becoming the most significant monitoring indicator. Their signals have been extensively applied to evaluate the machinability of workpiece materials, predict cutter breakage, estimate cutting tool wear, control machine tool chatter, determine stable machining parameters, and improve surface finish. Robust and effective sensing systems with capability of monitoring the cutting force in machine operations in real time are crucial for realizing the full potential of cutting capabilities of computer numerically controlled (CNC) tools. The main objective of this paper is to present a brief review of the existing achievements in the field of multi-component cutting force sensing systems in modern manufacturing.

  18. Cutaneous mechanisms of isometric ankle force control

    DEFF Research Database (Denmark)

    Choi, Julia T; Jensen, Jesper Lundbye; Leukel, Christian

    2013-01-01

    The sense of force is critical in the control of movement and posture. Multiple factors influence our perception of exerted force, including inputs from cutaneous afferents, muscle afferents and central commands. Here, we studied the influence of cutaneous feedback on the control of ankle force...... of transient stimulation on force error were greater when compared to continuous stimulation and lidocaine injection. Position-matching performance was unaffected by peroneal nerve or plantar nerve stimulation. Our results show that cutaneous feedback plays a role in the control of force output at the ankle...... joint. Understanding how the nervous system normally uses cutaneous feedback in motor control will help us identify which functional aspects are impaired in aging and neurological diseases....

  19. Multi-robot control interface

    Science.gov (United States)

    Bruemmer, David J [Idaho Falls, ID; Walton, Miles C [Idaho Falls, ID

    2011-12-06

    Methods and systems for controlling a plurality of robots through a single user interface include at least one robot display window for each of the plurality of robots with the at least one robot display window illustrating one or more conditions of a respective one of the plurality of robots. The user interface further includes at least one robot control window for each of the plurality of robots with the at least one robot control window configured to receive one or more commands for sending to the respective one of the plurality of robots. The user interface further includes a multi-robot common window comprised of information received from each of the plurality of robots.

  20. Telerobotic Control Architecture Including Force-Reflection

    National Research Council Canada - National Science Library

    Murphy, Mark

    1998-01-01

    This report describes the implementation of a telerobotic control architecture to manipulate a standard six-degree-of-freedom robot via a unique seven-degree-of-freedom force-reflecting exoskeleton...

  1. Controlling Casimir force via coherent driving field

    Science.gov (United States)

    Ahmad, Rashid; Abbas, Muqaddar; Ahmad, Iftikhar; Qamar, Sajid

    2016-04-01

    A four level atom-field configuration is used to investigate the coherent control of Casimir force between two identical plates made up of chiral atomic media and separated by vacuum of width d. The electromagnetic chirality-induced negative refraction is obtained via atomic coherence. The behavior of Casimir force is investigated using Casimir-Lifshitz formula. It is noticed that Casimir force can be switched from repulsive to attractive and vice versa via coherent control of the driving field. This switching feature provides new possibilities of using the repulsive Casimir force in the development of new emerging technologies, such as, micro-electro-mechanical and nano-electro-mechanical systems, i.e., MEMS and NEMS, respectively.

  2. Acoustic radiation force control: Pulsating spherical carriers.

    Science.gov (United States)

    Rajabi, Majid; Mojahed, Alireza

    2018-02-01

    power supply for distinct cases of zero, negative and positive radiation force states along with the frequency dependent asymmetry index. In addition, considering the effect of phase difference between the incident wave field and the pulsating object, and its possible variation with respect to spatial position of object, some practical points about the spatial average of generated radiation force, the optimal state of operation, the stability of zero radiation force states and the possibly of precise motion control are discussed. This work would extend the novel concept of smart carriers to and may be helpful for robust single-beam acoustic handling techniques. Furthermore, the shown capability of precise motion control may be considered as a new way toward smart acoustic driven micro-mechanisms and micro-machines. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. External force/velocity control for an autonomous rehabilitation robot

    Science.gov (United States)

    Saekow, Peerayuth; Neranon, Paramin; Smithmaitrie, Pruittikorn

    2018-01-01

    Stroke is a primary cause of death and the leading cause of permanent disability in adults. There are many stroke survivors, who live with a variety of levels of disability and always need rehabilitation activities on daily basis. Several studies have reported that usage of rehabilitation robotic devices shows the better improvement outcomes in upper-limb stroke patients than the conventional therapy-nurses or therapists actively help patients with exercise-based rehabilitation. This research focuses on the development of an autonomous robotic trainer designed to guide a stroke patient through an upper-limb rehabilitation task. The robotic device was designed and developed to automate the reaching exercise as mentioned. The designed robotic system is made up of a four-wheel omni-directional mobile robot, an ATI Gamma multi-axis force/torque sensor used to measure contact force and a microcontroller real-time operating system. Proportional plus Integral control was adapted to control the overall performance and stability of the autonomous assistive robot. External force control was successfully implemented to establish the behavioral control strategy for the robot force and velocity control scheme. In summary, the experimental results indicated satisfactorily stable performance of the robot force and velocity control can be considered acceptable. The gain tuning for proportional integral (PI) velocity control algorithms was suitably estimated using the Ziegler-Nichols method in which the optimized proportional and integral gains are 0.45 and 0.11, respectively. Additionally, the PI external force control gains were experimentally tuned using the trial and error method based on a set of experiments which allow a human participant moves the robot along the constrained circular path whilst attempting to minimize the radial force. The performance was analyzed based on the root mean square error (E_RMS) of the radial forces, in which the lower the variation in radial

  4. A Novel Atomic Force Microscope with Multi-Mode Scanner

    International Nuclear Information System (INIS)

    Qin, Chun; Zhang, Haijun; Xu, Rui; Han, Xu; Wang, Shuying

    2016-01-01

    A new type of atomic force microscope (AFM) with multi-mode scanner is proposed. The AFM system provides more than four scanning modes using a specially designed scanner with three tube piezoelectric ceramics and three stack piezoelectric ceramics. Sample scanning of small range with high resolution can be realized by using tube piezos, meanwhile, large range scanning can be achieved by stack piezos. Furthermore, the combination with tube piezos and stack piezos not only realizes high-resolution scanning of small samples with large- scale fluctuation structure, but also achieves small range area-selecting scanning. Corresponding experiments are carried out in terms of four different scanning modes showing that the AFM is of reliable stability, high resolution and can be widely applied in the fields of micro/nano-technology. (paper)

  5. Robust Force Control of Series Elastic Actuators

    Directory of Open Access Journals (Sweden)

    Andrea Calanca

    2014-07-01

    Full Text Available Force-controlled series elastic actuators (SEA are widely used in novel human-robot interaction (HRI applications, such as assistive and rehabilitation robotics. These systems are characterized by the presence of the “human in the loop”, so that control response and stability depend on uncertain human dynamics, including reflexes and voluntary forces. This paper proposes a force control approach that guarantees the stability and robustness of the coupled human-robot system, based on sliding-mode control (SMC, considering the human dynamics as a disturbance to reject. We propose a chattering free solution that employs simple task models to obtain high performance, comparable with second order solutions. Theoretical stability is proven within the sliding mode framework, and predictability is reached by avoiding the reaching phase by design. Furthermore, safety is introduced by a proper design of the sliding surface. The practical feasibility of the approach is shown using an SEA prototype coupled with a human impedance in severe stress tests. To show the quality of the approach, we report a comparison with state-of-the-art second order SMC, passivity-based control and adaptive control solutions.

  6. THE DEMOCRATIC CONTROL OF MILITARY FORCES

    Directory of Open Access Journals (Sweden)

    Smail Oštraković

    2011-04-01

    Full Text Available The transition requirement for post communism countries, especially the part that is about military forces is to establish those civil-military relation that will have prepared projects for awareness evolving of society and military about necessity of democratic control over military sector of country through development of many different communication forms and shapes. Before everything, it means the entire freedom and independence of media at access to military forces as the topic and subject of its interests and also the organization of public military communication system as integral part of information-communication system in society

  7. Multi-sensor control for precise assembly of optical components

    Directory of Open Access Journals (Sweden)

    Ma Li

    2014-06-01

    Full Text Available In order to perform an optical assembly accurately, a multi-sensor control strategy is developed which includes an attitude measurement system, a vision system, a loss measurement system and a force sensor. A 3-DOF attitude measuring method using linear variable differential transformers (LVDT is designed to adjust the relation of position and attitude between the spherical mirror and the resonator. A micro vision feedback system is set up to extract the light beam and the diaphragm, which can achieve the coarse positioning of the spherical mirror in the optical assembly process. A rapid self-correlation method is presented to analyze the spectrum signal for the fine positioning. In order to prevent the damage of the optical components and realize sealing of the resonator, a hybrid force-position control is constructed to control the contact force of the optical components. The experimental results show that the proposed multi-sensor control strategy succeeds in accomplishing the precise assembly of the optical components, which consists of parallel adjustment, macro coarse adjustment, macro approach, micro fine adjustment, micro approach and optical contact. Therefore, the results validate the multi-sensor control strategy.

  8. Geodetic Control Points - Multi-State Control Point Database

    Data.gov (United States)

    NSGIC State | GIS Inventory — The Multi-State Control Point Database (MCPD) is a database of geodetic and mapping control covering Idaho and Montana. The control were submitted by registered land...

  9. Multi-periodic nanostructures for photon control

    DEFF Research Database (Denmark)

    Kluge, Christian; Adam, Jost; Barié, Nicole

    2014-01-01

    We propose multi-periodic nanostructures yielded by superposition of multiple binary gratings for wide control over photon emission in thin-film devices. We present wavelength- and angle-resolved photoluminescence measurements of multi-periodically nanostructured organic light-emitting layers...

  10. Controller Synthesis for Periodically Forced Chaotic Systems

    Science.gov (United States)

    Basso, Michele; Genesio, Roberto; Giovanardi, Lorenzo

    Delayed feedback controllers are an appealing tool for stabilization of periodic orbits in chaotic systems. Despite their conceptual simplicity, specific and reliable design procedures are difficult to obtain, partly also because of their inherent infinite-dimensional structure. This chapter considers the use of finite dimensional linear time invariant controllers for stabilization of periodic solutions in a general class of sinusoidally forced nonlinear systems. For such controllers — which can be interpreted as rational approximations of the delayed ones — we provide a computationally attractive synthesis technique based on Linear Matrix Inequalities (LMIs), by mixing results concerning absolute stability of nonlinear systems and robustness of uncertain linear systems. The resulting controllers prove to be effective for chaos suppression in electronic circuits and systems, as shown by two different application examples.

  11. On multi-fingerprint detection and attribution of greenhouse gas- and aerosol forced climate change

    Energy Technology Data Exchange (ETDEWEB)

    Hegerl, G C [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Hasselmann, K [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Cubasch, U [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Mitchell, J F.B. [Hadley Centre for Climate Prediction and Research, Bracknell (United Kingdom). Meteorological Office; Roeckner, E [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Voss, R [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany); Waszkewitz, J [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

    1996-07-01

    A multi-fingerprint analysis is applied to the detection and attribution of anthropogenic climate change. While a single fingerprint, as applied in a previous paper by Hegerl et al. (1996), is optimal for detecting a significant climate change, the simultaneous use of several fingerprints allows one to investigate additionally the consistency between observations and model predicted climate change signals for competing candidate forcing mechanisms. Thus the multi-fingerprint method is a particularly useful technique for attributing an observed climate change to a proposed cause. Different model-predicted climate change signals are derived from three global warming simulations for the period 1880 to 2049. In one simulation, the forcing was by greenhouse gases only, while in the remaining two simulations the influence of aerosols was also included. The two dominant climate change signals derived from these simulations are optimized statistically by weighting the model-predicted climate change pattern towards low-noise directions. These optimized fingerprints are then applied to observed near surface temperature trends. The space-time structure of natural climate variability (needed to determine the signal-to-noise ratio) is estimated from several multi-century control simulations with different CGCMs and from instrumental data over the last 134 years. (orig.)

  12. 14 CFR 23.155 - Elevator control force in maneuvers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force...

  13. Development of isometric force and force control in children

    NARCIS (Netherlands)

    Smits-Engelsman, B.C.M.; Westenberg, Y.; Duysens, J.E.J.

    2004-01-01

    Fifty-six children between 5 and 12 years of age and 15 adults performed a task (pressing on a lever with the index finger of the preferred hand), in which a force had to be maintained constant at five levels with on-line visual feedback. Since this is a simple isometric task, the hypothesis is that

  14. Development of isometric force and force control in children.

    NARCIS (Netherlands)

    Smits-Engelsman, B.C.M.; Westenberg, Y.; Duysens, J.E.J.

    2003-01-01

    Fifty-six children between 5 and 12 years of age and 15 adults performed a task (pressing on a lever with the index finger of the preferred hand), in which a force had to be maintained constant at five levels with on-line visual feedback. Since this is a simple isometric task, the hypothesis is that

  15. Conflicting Multi-Objective Compatible Optimization Control

    OpenAIRE

    Xu, Lihong; Hu, Qingsong; Hu, Haigen; Goodman, Erik

    2010-01-01

    Based on ideas developed in addressing practical greenhouse environmental control, we propose a new multi-objective compatible control method. Several detailed algorithms are proposed to meet the requirements of different kinds of problem: 1) A two-layer MOCC framework is presented for problems with a precise model; 2) To deal with situations

  16. Levitation and guidance force relaxations of the single-seeded and multi-seeded YBCO superconductors

    Science.gov (United States)

    Abdioglu, M.; Ozturk, K.; Kabaer, M.; Ekici, M.

    2018-01-01

    The stable levitation and guidance forces at higher force levels are important parameters for technological applicability of high temperature superconductors (HTSs) in Maglev and Flywheel energy storage systems. In this study, we have investigated the levitation and guidance force relaxation of both the single-seeded and multi-seeded YBCOs for different (HTS)-permanent magnetic guideway (PMG) arrangements in different cooling heights (CH). The measured saturated force values of Halbach PMG arrangements are bigger than the maximum force values of other PMGs. It is determined that the normalized magnetic levitation force (MLF) and normalized guidance force (GF) relaxation rate values decrease while the relaxation rates increase with increasing magnetic pole number and the effective external magnetic field area for both the single-seeded and multi-seeded YBCO. Also it can be said that the force stability at the higher force value of Halbach PMG arrangement indicates that the relaxation quality of Halbach PMG is better than that of the others. Additionally, it can be said that both the MLF and GF relaxation qualities of the multi-seeded YBCOs are better than that of the single-seeded ones. This magnetic force and relaxation results of the single-seeded and multi-seeded YBCOs are useful to optimize the loading capacity and lateral reliability of HTS Maglev and similar magnetic bearing systems.

  17. Multi-finger prehension: control of a redundant mechanical system.

    Science.gov (United States)

    Latash, Mark L; Zatsiorsky, Vladimir M

    2009-01-01

    The human hand has been a fascinating object of study for researchers in both biomechanics and motor control. Studies of human prehension have contributed significantly to the progress in addressing the famous problem of motor redundancy. After a brief review of the hand mechanics, we present results of recent studies that support a general view that the apparently redundant design of the hand is not a source of computational problems but a rich apparatus that allows performing a variety of tasks in a reliable and flexible way (the principle of abundance). Multi-digit synergies have been analyzed at two levels of a hypothetical hierarchy involved in the control of prehensile actions. At the upper level, forces and moments produced by the thumb and virtual finger (an imagined finger with a mechanical action equal to the combined mechanical action of all four fingers of the hand) co-vary to stabilize the gripping action and the orientation of the hand-held object. These results support the principle of superposition suggested earlier in robotics with respect to the control of artificial grippers. At the lower level of the hierarchy, forces and moments produced by individual fingers co-vary to stabilize the magnitude and direction of the force vector and the moment of force produced by the virtual finger. Adjustments to changes in task constraints (such as, for example, friction under individual digits) may be local and synergic. The latter reflect multi-digit prehension synergies and may be analyzed with the so-called chain effects: Sequences of relatively straightforward cause-effect links directly related to mechanical constraints leading to non-trivial strong co-variation between pairs of elemental variables. Analysis of grip force adjustments during motion of hand-held objects suggests that the central nervous system adjusts to gravitational and inertial loads differently. The human hand is a gold mine for researchers interested in the control of natural human

  18. Disk access controller for Multi 8 computer

    International Nuclear Information System (INIS)

    Segalard, Jean

    1970-01-01

    After having presented the initial characteristics and weaknesses of the software provided for the control of a memory disk coupled with a Multi 8 computer, the author reports the development and improvement of this controller software. He presents the different constitutive parts of the computer and the operation of the disk coupling and of the direct access to memory. He reports the development of the disk access controller: software organisation, loader, subprograms and statements

  19. Multi-Axis Force Sensor for Human-Robot Interaction Sensing in a Rehabilitation Robotic Device.

    Science.gov (United States)

    Grosu, Victor; Grosu, Svetlana; Vanderborght, Bram; Lefeber, Dirk; Rodriguez-Guerrero, Carlos

    2017-06-05

    Human-robot interaction sensing is a compulsory feature in modern robotic systems where direct contact or close collaboration is desired. Rehabilitation and assistive robotics are fields where interaction forces are required for both safety and increased control performance of the device with a more comfortable experience for the user. In order to provide an efficient interaction feedback between the user and rehabilitation device, high performance sensing units are demanded. This work introduces a novel design of a multi-axis force sensor dedicated for measuring pelvis interaction forces in a rehabilitation exoskeleton device. The sensor is conceived such that it has different sensitivity characteristics for the three axes of interest having also movable parts in order to allow free rotations and limit crosstalk errors. Integrated sensor electronics make it easy to acquire and process data for a real-time distributed system architecture. Two of the developed sensors are integrated and tested in a complex gait rehabilitation device for safe and compliant control.

  20. Special Forces Command and Control in Afghanistan

    National Research Council Canada - National Science Library

    Rhyne, Richard

    2004-01-01

    .... The author examines how Special Forces and conventional forces worked together in the past in Vietnam, Panama, Somalia, Haiti, Bosnia-Herzegovina, and Operations Desert Storm and Desert Shield...

  1. Quantum control of multi-wave mixing

    CERN Document Server

    Zhang, Yanpeng; Xiao, Min

    2013-01-01

    Multi-wave mixing gives rise to new frequency components due to the interaction of light signals with a suitable nonlinear medium. In this book a systematic framework for the control of these processes is used to lead readers through a plethora of related effects and techniques.

  2. Artificial force fields for multi-agent simulations of maritime traffic and risk estimation

    NARCIS (Netherlands)

    Xiao, F.; Ligteringen, H.; Van Gulijk, C.; Ale, B.J.M.

    2012-01-01

    A probabilistic risk model is designed to estimate probabilities of collisions for shipping accidents in busy waterways. We propose a method based on multi-agent simulation that uses an artificial force field to model ship maneuvers. The artificial force field is calibrated by AIS data (Automatic

  3. Control of flow geometry using electromagnetic body forcing

    International Nuclear Information System (INIS)

    Rossi, L.; Bocquet, S.; Ferrari, S.; Garcia de la Cruz, J.M.; Lardeau, S.

    2009-01-01

    This paper presents conceptual experiments and simulations aiming at controlling flow geometries. Such flow design is performed by driving electromagnetically a shallow layer of brine, the forcing being generated by a transverse electrical current and different combinations of permanent magnets placed underneath the brine supporting wall. It is shown how different basic flow characteristics can be obtained with a single pair of magnets, by varying the angle with the electrical current. These basic flows are proposed as potential building blocks for advanced and complex flows studies. Three typical flow structures are presented to illustrate these building blocks. The discussion is then extended to multi-scale geometry by using blocks of various sizes. The flow is analysed using complementary experiments and numerical simulations. A good agreement is found between the 3D simulations and the experiments for both velocity and acceleration fields, which allows a higher degree of confidence in designing and modelling such flows. As the control of the flow geometry is important for mixing, in particular at low Reynolds number, we also illustrate the different stirring properties of the electromagnetically forced flows by comparing visualisations of passive scalars. They reveal complementary mixing properties for each of the building blocks.

  4. Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures

    Directory of Open Access Journals (Sweden)

    Keunhee Cho

    2015-06-01

    Full Text Available Prestressed concrete (PSC is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

  5. Estimation of Prestress Force Distribution in the Multi-Strand System of Prestressed Concrete Structures.

    Science.gov (United States)

    Cho, Keunhee; Park, Sung Yong; Cho, Jeong-Rae; Kim, Sung Tae; Park, Young-Hwan

    2015-06-15

    Prestressed concrete (PSC) is one of the most reliable, durable and widely used construction materials, which overcomes the weakness of concrete in tension by the introduction of a prestress force. Smart strands enabling measurement of the prestress force have recently been developed to maintain PSC structures throughout their lifetime. However, the smart strand cannot give a representative indication of the whole prestress force when used in multi-strand systems since each strand sustains a different prestress force. In this paper, the actual distribution of the prestress force in a multi-strand system is examined using elastomagnetic (EM) sensors to develop a method for tracking representative indicators of the prestress force using smart strands.

  6. Gemstone Grinding Process Improvement by using Impedance Force Control

    Directory of Open Access Journals (Sweden)

    Hamprommarat Chumpol

    2015-01-01

    Full Text Available Chula Automatic Faceting Machine has been developed by The Advance Manufacturing Research Lab, Chulalongkorn University to support Thailand Gems-Industry. The machine has high precision motion control by using position and force control. A contact stiffness model is used to estimate grinding force. Although polished gems from the Faceting Machine have uniform size and acceptable shape, the force of the grinding and polishing process cannot be maintain constant and has some fluctuation due to indirect force control. Therefor this research work propose a new controller for this process based on an impedance direct force control to improve the gemstone grinding performance during polishing process. The grinding force can be measured through motor current. The results show that the polished gems by using impedance direct force control can maintain uniform size as well as good shape and high quality surface.

  7. Sliding mode-based lateral vehicle dynamics control using tyre force measurements

    Science.gov (United States)

    Kunnappillil Madhusudhanan, Anil; Corno, Matteo; Holweg, Edward

    2015-11-01

    In this work, a lateral vehicle dynamics control based on tyre force measurements is proposed. Most of the lateral vehicle dynamics control schemes are based on yaw rate whereas tyre forces are the most important variables in vehicle dynamics as tyres are the only contact points between the vehicle and road. In the proposed method, active front steering is employed to uniformly distribute the required lateral force among the front left and right tyres. The force distribution is quantified through the tyre utilisation coefficients. In order to address the nonlinearities and uncertainties of the vehicle model, a gain scheduling sliding-mode control technique is used. In addition to stabilising the lateral dynamics, the proposed controller is able to maintain maximum lateral acceleration. The proposed method is tested and validated on a multi-body vehicle simulator.

  8. Force-sensed interface for control and training space robot

    Science.gov (United States)

    Moiseev, O. S.; Sarsadskikh, A. S.; Povalyaev, N. D.; Gorbunov, V. I.; Kulakov, F. M.; Vasilev, V. V.

    2018-05-01

    A method of positional and force-torque control of robots is proposed. Prototypes of the system and the master handle have been created. Algorithm of bias estimation and gravity compensation for force-torque sensor and force-torque trajectory correction are described.

  9. Force Reflection Algorithms for Exoskeleton Controllers

    National Research Council Canada - National Science Library

    Bryfogle, Mark

    1991-01-01

    This research effort investigated the kinematics and dynamics of open chain, serial linkage mechanisms with specific emphasis placed upon the application of this linkage as a force reflecting exoskeleton mechanism...

  10. Computer-Controlled Force Generator, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — TDA Research, Inc. is developing a compact, low power, Next-Generation Exercise Device (NGRED) that can generate any force between 5 and 600 lbf. We use a closed...

  11. High Cable Forces Deteriorate Pinch Force Control in Voluntary-Closing Body-Powered Prostheses.

    Directory of Open Access Journals (Sweden)

    Mona Hichert

    Full Text Available It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Body-powered prostheses (BPPs provide the user with direct proprioceptive feedback. Currently available BPPs often require high cable operation forces, which complicates control of the forces at the terminal device. The aim of this study is to quantify the influence of high cable forces on object manipulation with voluntary-closing prostheses.Able-bodied male subjects were fitted with a bypass-prosthesis with low and high cable force settings for the prehensor. Subjects were requested to grasp and transfer a collapsible object as fast as they could without dropping or breaking it. The object had a low and a high breaking force setting.Subjects conducted significantly more successful manipulations with the low cable force setting, both for the low (33% more and high (50% object's breaking force. The time to complete the task was not different between settings during successful manipulation trials.High cable forces lead to reduced pinch force control during object manipulation. This implies that low cable operation forces should be a key design requirement for voluntary-closing BPPs.

  12. Multi-drug resistant Acinetobacter infections in critically injured Canadian forces soldiers

    Directory of Open Access Journals (Sweden)

    Brisebois Ronald

    2007-08-01

    Full Text Available Abstract Background Military members, injured in Afghanistan or Iraq, have returned home with multi-drug resistant Acinetobacter baumannii infections. The source of these infections is unknown. Methods Retrospective study of all Canadian soldiers who were injured in Afghanistan and who required mechanical ventilation from January 1 2006 to September 1 2006. Patients who developed A. baumannii ventilator associated pneumonia (VAP were identified. All A. baumannii isolates were retrieved for study patients and compared with A. baumannii isolates from environmental sources from the Kandahar military hospital using pulsed-field gel electrophoresis (PFGE. Results During the study period, six Canadian Forces (CF soldiers were injured in Afghanistan, required mechanical ventilation and were repatriated to Canadian hospitals. Four of these patients developed A. baumannii VAP. A. baumannii was also isolated from one environmental source in Kandahar – a ventilator air intake filter. Patient isolates were genetically indistinguishable from each other and from the isolates cultured from the ventilator filter. These isolates were resistant to numerous classes of antimicrobials including the carbapenems. Conclusion These results suggest that the source of A. baumannii infection for these four patients was an environmental source in the military field hospital in Kandahar. A causal linkage, however, was not established with the ventilator. This study suggests that infection control efforts and further research should be focused on the military field hospital environment to prevent further multi-drug resistant A. baumannii infections in injured soldiers.

  13. Force Control Strategies in Hydraulically Actuated Legged Robots

    Directory of Open Access Journals (Sweden)

    Hector Montes

    2016-03-01

    Full Text Available In this contribution, several strategies of force control have been proposed to be implemented and evaluated in ROBOCLIMBER, a quadruped robot of large dimensions. A first group of strategies proposed in this paper is based on impedance control, which is intended to adapt the foot-ground contact forces according to the experimentally specified damping ratio and the undamped natural frequency. A second control strategy of interest for many practical cases is called the parallel force/position control, which has one inner loop position control and two external control loops, one of force and another of position. A third group of control strategies is the posture stabilization for ROBOCLIMBER using the feedback of the ZMP calculation and the position of its legs. Finally, a control strategy for the control of a quasi-static gait using ZMP feedback is proposed and tested by simulation.

  14. Neural control of muscle force: indications from a simulation model

    Science.gov (United States)

    Luca, Carlo J. De

    2013-01-01

    We developed a model to investigate the influence of the muscle force twitch on the simulated firing behavior of motoneurons and muscle force production during voluntary isometric contractions. The input consists of an excitatory signal common to all the motor units in the pool of a muscle, consistent with the “common drive” property. Motor units respond with a hierarchically structured firing behavior wherein at any time and force, firing rates are inversely proportional to recruitment threshold, as described by the “onion skin” property. Time- and force-dependent changes in muscle force production are introduced by varying the motor unit force twitches as a function of time or by varying the number of active motor units. A force feedback adjusts the input excitation, maintaining the simulated force at a target level. The simulations replicate motor unit behavior characteristics similar to those reported in previous empirical studies of sustained contractions: 1) the initial decrease and subsequent increase of firing rates, 2) the derecruitment and recruitment of motor units throughout sustained contractions, and 3) the continual increase in the force fluctuation caused by the progressive recruitment of larger motor units. The model cautions the use of motor unit behavior at recruitment and derecruitment without consideration of changes in the muscle force generation capacity. It describes an alternative mechanism for the reserve capacity of motor units to generate extraordinary force. It supports the hypothesis that the control of motoneurons remains invariant during force-varying and sustained isometric contractions. PMID:23236008

  15. Virtual Control of Prosthetic Hand Based on Grasping Patterns and Estimated Force from Semg

    Directory of Open Access Journals (Sweden)

    Zhu Gao-Ke

    2016-01-01

    Full Text Available Myoelectric prosthetic hands aim to serve upper limb amputees. The myoelectric control of the hand grasp action is a kind of real-time or online method. Thus it is of great necessity to carry on a study of online prosthetic hand electrical control. In this paper, the strategy of simultaneous EMG decoding of grasping patterns and grasping force was realized by controlling a virtual multi-degree-freedom prosthetic hand and a real one-degree-freedom prosthetic hand simultaneously. The former realized the grasping patterns from the recognition of the sEMG pattern. The other implemented the grasping force from sEMG force decoding. The results show that the control method is effective and feasible.

  16. Adaptation of multi-joint balance coordination to whole body force fields

    NARCIS (Netherlands)

    Engelhart, Denise; Schouten, Alfred Christiaan; Pasma, Jantsje; Aarts, Ronald G.K.M.; Pasma, J.; Meskers, Carel; Maier, Andrea; van der Kooij, Herman

    2014-01-01

    Background and aim: The ankles and the hips play an important role in standing balance. Multi-joint coordination adapts with task, the magnitude and type of disturbance [1]. Arm studies show that postural responses are highly dependent on externally applied force fields [2]. Our aim is to study how

  17. Precision Force Control for an Electro-Hydraulic Press Machine

    Directory of Open Access Journals (Sweden)

    Hong-Ming Chen

    2014-08-01

    Full Text Available This thesis is primarily intended to design a PC-based control system to control the force of an electro-hydraulic servo press system for implementing precision force control. The main feature is to develop a composite control by using the relief valve and the flow servo valve. Using feedback from a force sensor, a fuzzy controller was designed with LabVIEW software as the system control core for achieving a precision force control for the hydraulic cylinder on its travel and output. The weakness of hydraulic systems is that hydraulic oil is compressible and prone to leaking, and its characteristics can vary with oil temperature, thus making it difficult for a general linear controller to achieve accurate control. Therefore, a fuzzy controller was designed with LabVIEW along with a NI-PCI_6221 interface card and a load cell to control the servo valve flow and the relief valve to control the pressure source. The testing results indicate that accurate force control output of an electro-hydraulic servo press system can be obtained.

  18. A novel adaptive force control method for IPMC manipulation

    International Nuclear Information System (INIS)

    Hao, Lina; Sun, Zhiyong; Su, Yunquan; Gao, Jianchao; Li, Zhi

    2012-01-01

    IPMC is a type of electro-active polymer material, also called artificial muscle, which can generate a relatively large deformation under a relatively low input voltage (generally speaking, less than 5 V), and can be implemented in a water environment. Due to these advantages, IPMC can be used in many fields such as biomimetics, service robots, bio-manipulation, etc. Until now, most existing methods for IPMC manipulation are displacement control not directly force control, however, under most conditions, the success rate of manipulations for tiny fragile objects is limited by the contact force, such as using an IPMC gripper to fix cells. Like most EAPs, a creep phenomenon exists in IPMC, of which the generated force will change with time and the creep model will be influenced by the change of the water content or other environmental factors, so a proper force control method is urgently needed. This paper presents a novel adaptive force control method (AIPOF control—adaptive integral periodic output feedback control), based on employing a creep model of which parameters are obtained by using the FRLS on-line identification method. The AIPOF control method can achieve an arbitrary pole configuration as long as the plant is controllable and observable. This paper also designs the POF and IPOF controller to compare their test results. Simulation and experiments of micro-force-tracking tests are carried out, with results confirming that the proposed control method is viable. (paper)

  19. Greenidge Multi-Pollutant Control Project

    Energy Technology Data Exchange (ETDEWEB)

    Connell, Daniel

    2008-10-18

    The Greenidge Multi-Pollutant Control Project was conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electric generating units (EGUs). There are about 400 units in the United States with capacities of 50-300 MW that currently are not equipped with selective catalytic reduction (SCR), flue gas desulfurization (FGD), or mercury control systems. Many of these units, which collectively represent more than 55 GW of installed capacity, are difficult to retrofit for deep emission reductions because of space constraints and unfavorable economies of scale, making them increasingly vulnerable to retirement or fuel switching in the face of progressively more stringent environmental regulations. The Greenidge Project sought to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs by offering a combination of deep emission reductions, low capital costs, small space requirements, applicability to high-sulfur coals, mechanical simplicity, and operational flexibility. The multi-pollutant control system includes a NO{sub x}OUT CASCADE{reg_sign} hybrid selective non-catalytic reduction (SNCR)/in-duct SCR system for NO{sub x} control and a Turbosorp{reg_sign} circulating fluidized bed dry scrubbing system (with a new baghouse) for SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter control. Mercury removal is provided as a co-benefit of the in-duct SCR, dry scrubber, and baghouse, and by injection of activated carbon upstream of the scrubber, if required. The multi-pollutant control system was installed and tested on the 107-MW{sub e}, 1953-vintage AES Greenidge Unit 4 by a team including

  20. Research on Grinding and Polishing Force Control of Compliant Flange

    Directory of Open Access Journals (Sweden)

    Li Chuang

    2015-01-01

    Full Text Available The automation of the grinding and polishing process is important to improve the production efficiency of the part surfaces. In this paper, a new compliant flange mounted on the end of the industrial robots for the robotic grinding and polishing force control is developed. With regard to the non-linear and time-varying problem of the contact force, the mathematical model of the new force control system was presented and the fuzzy PID control strategy was used to drive the proposed system. Especially, the air spring and electric proportional valve is studied to establish the model. The simulation results show that the selected control strategy has quick response and good robustness, which satisfies the real-time requirements of the grinding and polishing force control in processing.

  1. Force characteristics in continuous path controlled crankpin grinding

    Science.gov (United States)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  2. Advances in Multi-Pollutant Control

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-11-01

    Pollutants, such as nitrogen oxides (nitrogen dioxide (NO2) and nitric oxide (NO)), sulphur dioxide (SO2), sulphur trioxide (SO3), carbon dioxide (CO2), mercury (Hg) and particulate matter (PM), are formed when coal is combusted in a power plant boiler. With the concern over the environmental and health consequences of these pollutants, legislation and regulations have been implemented limiting the amounts that can be emitted to the atmosphere. Emission control systems on conventional coal-fired power plants typically employ technologies designed to remove one specific pollutant.These are then combined, in series, to remove several pollutants in order to meet the emission regulations. This report discusses multi-pollutant systems which remove two or more of the principal regulated pollutants (SO2, NOx, mercury, particulate matter and CO2) in a single reactor or a single system designed for the purpose. The emphasis is on commercial or near commercial processes, and those that are under active development. Ways to improve the co-benefit removal of oxidised mercury in conventional limestone wet scrubbers, spray dry scrubbers and circulating dry scrubbers are also included. Multi-pollutant systems can have lower capital and operating costs than a series of traditional systems to remove the s ame number of pollutants. Nevertheless, many of the multi-pollutant technologies rely on by-product sales to be economically competitive. Their footprint is often smaller than conventional single pollutant counterparts treating a similar volume of flue gas, making them easier to install in retrofit applications. Some of the systems use modular designs that ensures easy scalability for larger boilers.

  3. Control of force during rapid visuomotor force-matching tasks can be described by discrete time PID control algorithms.

    Science.gov (United States)

    Dideriksen, Jakob Lund; Feeney, Daniel F; Almuklass, Awad M; Enoka, Roger M

    2017-08-01

    Force trajectories during isometric force-matching tasks involving isometric contractions vary substantially across individuals. In this study, we investigated if this variability can be explained by discrete time proportional, integral, derivative (PID) control algorithms with varying model parameters. To this end, we analyzed the pinch force trajectories of 24 subjects performing two rapid force-matching tasks with visual feedback. Both tasks involved isometric contractions to a target force of 10% maximal voluntary contraction. One task involved a single action (pinch) and the other required a double action (concurrent pinch and wrist extension). 50,000 force trajectories were simulated with a computational neuromuscular model whose input was determined by a PID controller with different PID gains and frequencies at which the controller adjusted muscle commands. The goal was to find the best match between each experimental force trajectory and all simulated trajectories. It was possible to identify one realization of the PID controller that matched the experimental force produced during each task for most subjects (average index of similarity: 0.87 ± 0.12; 1 = perfect similarity). The similarities for both tasks were significantly greater than that would be expected by chance (single action: p = 0.01; double action: p = 0.04). Furthermore, the identified control frequencies in the simulated PID controller with the greatest similarities decreased as task difficulty increased (single action: 4.0 ± 1.8 Hz; double action: 3.1 ± 1.3 Hz). Overall, the results indicate that discrete time PID controllers are realistic models for the neural control of force in rapid force-matching tasks involving isometric contractions.

  4. Computer controlled multi-leaf conformation radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, T [Tokyo Metropolitan Komagome Hospital (Japan); Inamura, K

    1981-10-01

    A conformation radiotherapy system with 5-split collimators of which openings can be controlled symmetrically by computerized techniques during rotational irradiation by a linear accelerator has been developed. Outline of the system performance and its clinical applications are described as follows. 1. Profile of the system: The hardware is composed of three parts, namely, the multi-split collimator, the electronic data processor, and the interface between those two parts. 1) The multi-leaf collimator is composed of 5 pairs (10 leaves) diaphragms. It can be mounted to the X-ray head of a linear accelerator when used, and can be dismounted after its use. 2) The electronic data processor sends control signal to the collimator according to the 5-leaf target volume data which can be stored into a minifloppy disc through the curve digitizer previously. This part is composed of a) dedicated micro processor, b) I/O expansion unit, c) color CRT display with key board, d) dual mini-floppy disc unit, e) curve digitizer and f) digital plotter for recording and verification of resulted accuracy. 2. Performance of the system: 1) Maximum field size: 15 cm x 15 cm at isocenter. 2) Maximum elongation ratio of the target volume: 3 : 1 when the longer diameter is 15 cm. 3) Control accuracy: Within +-3 mm deviation from planned beam focus at isocenter. 3. Clinical application: The method of treatment planning and clinical advantages of this irradiation method are explained by raising clinical experiences such as treating brain tumor and rectal cancer.

  5. Computer controlled multi-leaf conformation radiotherapy

    International Nuclear Information System (INIS)

    Matsuda, Tadayoshi; Inamura, Kiyonari.

    1981-01-01

    A conformation radiotherapy system with 5-split collimators of which openings can be controlled symmetrically by computerized techniques during rotational irradiation by a linear accelerator has been developed. Outline of the system performance and its clinical applications are described as follows. 1. Profile of the system: The hardware is composed of three parts, namely, the multi-split collimator, the electronic data processor, and the interface between those two parts. 1) The multi-leaf collimator is composed of 5 pairs (10 leaves) diaphragms. It can be mounted to the X-ray head of a linear accelerator when used, and can be dismounted after its use. 2) The electronic data processor sends control signal to the collimator according to the 5-leaf target volume data which can be stored into a minifloppy disc through the curve digitizer previously. This part is composed of a) dedicated micro processor, b) I/O expansion unit, c) color CRT display with key board, d) dual mini-floppy disc unit, e) curve digitizer and f) digital plotter for recording and verification of resulted accuracy. 2. Performance of the system: 1) Maximum field size: 15 cm x 15 cm at isocenter. 2) Maximum elongation ratio of the target volume: 3 : 1 when the longer diameter is 15 cm. 3) Control accuracy: Within +-3 mm deviation from planned beam focus at isocenter. 3. Clinical application: The method of treatment planning and clinical advantages of this irradiation method are explained by raising clinical experiences such as treating brain tumor and rectal cancer. (author)

  6. Remodeling Air Force Cyber Command and Control

    Science.gov (United States)

    2017-10-10

    Internet, telecommunications networks, computer systems , and embedded processors and controllers .” That last phrase includes processors and controllers ...embedded” into weapons systems , including aircraft and spacecraft. Many weapon systems were built and connected before cyberspace became a...problems for systemic improvement of mission assurance. The benefit of a centralized environment could also extend to improving enterprise-level patch

  7. Radial electromagnetic force calculation of induction motor based on multi-loop theory

    Directory of Open Access Journals (Sweden)

    HE Haibo

    2017-12-01

    Full Text Available [Objectives] In order to study the vibration and noise of induction motors, a method of radial electromagnetic force calculation is established on the basis of the multi-loop model.[Methods] Based on the method of calculating air-gap magneto motive force according to stator and rotor fundamental wave current, the analytic formulas are deduced for calculating the air-gap magneto motive force and radial electromagnetic force generated in accordance with any stator winding and rotor conducting bar current. The multi-loop theory and calculation method for the electromagnetic parameters of a motor are introduced, and a dynamic simulation model of an induction motor built to achieve the current of the stator winding and rotor conducting bars, and obtain the calculation formula of radial electromagnetic force. The radial electromagnetic force and vibration are then estimated.[Results] The experimental results indicate that the vibration acceleration frequency and amplitude of the motor are consistent with the experimental results.[Conclusions] The results and calculation method can support the low noise design of converters.

  8. Controlling Force and Depth in Friction Stir Welding

    Science.gov (United States)

    Adams, Glynn; Loftus, Zachary; McCormac, Nathan; Venable, Richard

    2005-01-01

    Feedback control of the penetration force applied to a pin tool in friction stir welding has been found to be a robust and reliable means for controlling the depth of penetration of the tool. This discovery has made it possible to simplify depth control and to weld with greater repeatability, even on workpieces with long weld joints. Prior to this discovery, depths of penetration in friction stir welding were controlled by hard-tooled roller assemblies or by depth actuators controlled by feedback from such external sensors as linear variable-differential transformers or laser-based devices. These means of control are limited: A hard-tooled roller assembly confines a pin tool to a preset depth that cannot be changed easily during the welding process. A measurement by an external sensor is only an indirect indicative of the depth of penetration, and computations to correlate such a measurement with a depth of penetration are vulnerable to error. The present force-feedback approach exploits the proportionality between the depth and the force of penetration Unlike a depth measurement taken by an external sensor, a force measurement can be direct because it can be taken by a sensor coupled directly to the pin tool. The reading can be processed through a modern electronic servo control system to control an actuator to keep the applied penetration force at the desired level. In comparison with the older depth-control methods described above, this method offers greater sensitivity to plasticizing of the workpiece metal and is less sensitive to process noise, resulting in a more consistent process. In an experiment, a tapered panel was friction stir welded while controlling the force of penetration according to this method. The figure is a plot of measurements taken during the experiment, showing that force was controlled with a variation of 200 lb (890 N), resulting in control of the depth of penetration with a variation of 0.004 in. (0.1 mm).

  9. Integrated Process Design and Control of Multi-element Reactive Distillation Processes

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil; Sales-Cruz, Mauricio; Huusom, Jakob Kjøbsted

    2016-01-01

    In this work, integrated process design and control of reactive distillation processes involving multi-elements is presented. The reactive distillation column is designed using methods and tools which are similar in concept to non-reactive distillation design methods, such as driving force approach....... The methods employed in this work are based on equivalent element concept. This concept facilitates the representation of a multi-element reactive system as equivalent binary light and heavy key elements. First, the reactive distillation column is designed at the maximum driving force where through steady...

  10. Performance evaluation on force control for ITER blanket installation

    Energy Technology Data Exchange (ETDEWEB)

    Aburadani, A., E-mail: aburadani.atsushi@jaea.go.jp [Japan Atomic Energy Agency, Mukouyama 801-1, Naka, Ibaraki 311-0193 (Japan); Takeda, N.; Shigematsu, S.; Murakami, S.; Tanigawa, H.; Kakudate, S. [Japan Atomic Energy Agency, Mukouyama 801-1, Naka, Ibaraki 311-0193 (Japan); Nakahira, M.; Hamilton, D.; Tesini, A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    Highlights: ► It is crucial issues to avoid any jamming between the blanket modules and the keys. ► Force control for AC servo motor was developed to reduce excessive loads. ► This jam prevention force control method is directly measured and controlled by AC servo motor controllers. ► In the recent test, the module was passively positioned onto keys using the torque control method. -- Abstract: The most critical issue for the ITER blanket installation is to avoid any jamming between the blanket modules and the keys as a result of excessive loading during the module installation process. This is complicated by the limited clearance of 0.5 mm between the modules and the keys. To solve these technical issues, force control, such as controlling the torque for the AC servo motors, was developed to reduce excessive loads which may have an impact on the end-effector and to defer the forces acting on the groove of the blanket. This jam prevention force control method is directly measured and controlled by AC servo motor controllers. The AC servo motors are equipped to move the manipulator and end-effector during module installation.

  11. Performance evaluation on force control for ITER blanket installation

    International Nuclear Information System (INIS)

    Aburadani, A.; Takeda, N.; Shigematsu, S.; Murakami, S.; Tanigawa, H.; Kakudate, S.; Nakahira, M.; Hamilton, D.; Tesini, A.

    2013-01-01

    Highlights: ► It is crucial issues to avoid any jamming between the blanket modules and the keys. ► Force control for AC servo motor was developed to reduce excessive loads. ► This jam prevention force control method is directly measured and controlled by AC servo motor controllers. ► In the recent test, the module was passively positioned onto keys using the torque control method. -- Abstract: The most critical issue for the ITER blanket installation is to avoid any jamming between the blanket modules and the keys as a result of excessive loading during the module installation process. This is complicated by the limited clearance of 0.5 mm between the modules and the keys. To solve these technical issues, force control, such as controlling the torque for the AC servo motors, was developed to reduce excessive loads which may have an impact on the end-effector and to defer the forces acting on the groove of the blanket. This jam prevention force control method is directly measured and controlled by AC servo motor controllers. The AC servo motors are equipped to move the manipulator and end-effector during module installation

  12. Force analysis of magnetic bearings with power-saving controls

    International Nuclear Information System (INIS)

    Johnson, D.; Brown, G.V.; Inman, D.J.

    1992-01-01

    Most magnetic bearing control schemes use a bias current with a superimposed control current to linearize the relationship between the control current and the force it delivers. For most operating conditions, the existence of the bias current requires more power than alternative methods that do not use conventional bias. Two such methods are examined which diminish or eliminate bias current. In the typical bias control scheme it is found that for a harmonic control force command into a voltage limited transconductance amplifier, the desired force output is obtained only up to certain combinations of force amplitude and frequency. Above these values, the force amplitude is reduced and a phase lag occurs. The power saving alternative control schemes typically exhibit such deficiencies at even lower command frequencies and amplitudes. To assess the severity of these effects, a time history analysis of the force output is performed for the bias method and the alternative methods. Results of the analysis show that the alternative approaches may be viable. The various control methods examined were mathematically modeled using nondimensionalized variables to facilitate comparison of the various methods

  13. The Air Force Center for Optimal Design and Control

    National Research Council Canada - National Science Library

    Burns, John

    1997-01-01

    This report contains a summary and highlights of the research funded by the Air Force under AFOSR URI Grant F49620-93-1-0280, titled 'Center for Optimal Design and Control of Distributed Parameter Systems' (CODAC...

  14. Force control for mechanoinduction of impedance variation in cellular organisms

    International Nuclear Information System (INIS)

    Nam, Joo Hoo; Chen, Peter C Y; Lu, Zhe; Luo, Hong; Lin, Wei; Ge, Ruowen

    2010-01-01

    Constantly exposed to various forms of mechanical forces inherent in their physical environment (such as gravity, stress induced by fluid flow or cell–cell interactions, etc), cellular organisms sense such forces and convert them into biochemical signals through the processes of mechanosensing and mechanotransduction that eventually lead to biological changes. The effect of external forces on the internal structures and activities in a cellular organism may manifest in changes its physical properties, such as impedance. Studying variation in the impedance of a cellular organism induced by the application of an external mechanical force represents a meaningful endeavor (from a biosystems perspective) in exploring the complex mechanosensing and mechanotransduction mechanisms that govern the behavior of a cellular organism under the influence of external mechanical stimuli. In this paper we describe the development of an explicit force-feedback control system for exerting an indentation force on a cellular organism while simultaneously measuring its impedance. To demonstrate the effectiveness of this force-control system, we have conducted experiments using zebrafish embryos as a test model of a cellular organism. We report experimental results demonstrating that the application of a properly controlled external force leads to a significant change in the impedance of a zebrafish embryo. These results offer support for a plausible explanation that activities of pore canals in the chorion are responsible for the observed change in impedance.

  15. Control Prosody using Multi-Agent System

    Directory of Open Access Journals (Sweden)

    Kenji MATSUI

    2014-03-01

    Full Text Available Persons who have undergone a laryngectomy have a few options to partially restore speech but no completely satisfactory device. Even though the use of an electrolarynx (EL is the easiest way for a patient to produce speech, it does not produce a natural tone and appearance is far from normal. Because of that and the fact that none of them are hands-free, the feasibility of using a motion sensor to replace a conventional EL user interface has been explored. A mobile device motion sensor with multi-agent platform has been used to investigate on/off and pitch frequency control capability. A very small battery operated ARM-based control unit has also been developed to evaluate the motion sensor based user-interface. This control unit is placed on the wrist and the vibration device against the throat using support bandage. Two different conversion methods were used for the forearm tilt angle to pitch frequency conversion: linear mapping method and F0 template-based method A perceptual evaluation has been performed with two well-trained normal speakers and ten subjects. The results of the evaluation study showed that both methods are able to produce better speech quality in terms of the naturalness.

  16. Hybrid viscous damper with filtered integral force feedback control

    DEFF Research Database (Denmark)

    Høgsberg, Jan; Brodersen, Mark L.

    2016-01-01

    In hybrid damper systems active control devices are usually introduced to enhance the performance of otherwise passive dampers. In the present paper a hybrid damper concept is comprised of a passive viscous damper placed in series with an active actuator and a force sensor. The actuator motion...... is controlled by a filtered integral force feedback strategy, where the main feature is the filter, which is designed to render a damper force that in a phase-plane representation operates in front of the corresponding damper velocity. It is demonstrated that in the specific parameter regime where the damper...

  17. Theoretical analysis of steady state operating forces in control valves

    Directory of Open Access Journals (Sweden)

    Basavaraj Hubballi

    2018-01-01

    Full Text Available The controlling components, such as valves are used to regulate controlled fluid power. It is not always possible to calculate valve forces accurately, and with some types of valves even the existence of certain types of forces cannot be predicted with certainty. In many cases, however, the analysis can be made fairly completely and accurately. The assumption of steady state conditions is valid for the valve alone, but transient effects in the rest of the system may be large. These effects are particularly important with regard to the instability of valves, where the system may react on the valve in such a way as to make it squeal or oscillate, sometimes with large amplitude. The origin of the steady state flow force understood from a brief qualitative explanation. The following paper will summarize much of what is known about valve forces in the spool type controlling element.

  18. Environmental forcing, invasion and control of ecological and epidemiological systems.

    Science.gov (United States)

    Greenman, J V; Norman, R A

    2007-08-07

    Destabilising a biological system through periodic or stochastic forcing can lead to significant changes in system behaviour. Forcing can bring about coexistence when previously there was exclusion; it can excite massive system response through resonance, it can offset the negative effect of apparent competition and it can change the conditions under which the system can be invaded. Our main focus is on the invasion properties of continuous time models under periodic forcing. We show that invasion is highly sensitive to the strength, period, phase, shape and configuration of the forcing components. This complexity can be of great advantage if some of the forcing components are anthropogenic in origin. They can be turned into instruments of control to achieve specific objectives in ecology and disease management, for example. Culling, vaccination and resource regulation are considered. A general analysis is presented, based on the leading Lyapunov exponent criterion for invasion. For unstructured invaders, a formula for this exponent can typically be written down from the model equations. Whether forcing hinders or encourages invasion depends on two factors: the covariances between invader parameters and resident populations and the shifts in average resident population levels brought about by the forcing. The invasion dynamics of a structured invader are much more complicated but an analytic solution can be obtained in quadratic approximation for moderate forcing strength. The general theory is illustrated by a range of models drawn from ecology and epidemiology. The relationship between periodic and stochastic forcing is also considered.

  19. Force Feedback Control Method of Active Tuned Mass Damper

    Directory of Open Access Journals (Sweden)

    Xiuli Wang

    2017-01-01

    Full Text Available Active tuned mass dampers as vibration-control devices are widely used in many fields for their good stability and effectiveness. To improve the performance of such dampers, a control method based on force feedback is proposed. The method offers several advantages such as high-precision control and low-performance requirements for the actuator, as well as not needing additional compensators. The force feedback control strategy was designed based on direct-velocity feedback. The effectiveness of the method was verified in a single-degree-of-freedom system, and factors such as damping effect, required active force, actuator stroke, and power consumption of the damper were analyzed. Finally, a simulation study was performed by configuring a main complex elastic-vibration-damping system. The results show that the method provides effective control over modal resonances of multiple orders of the system and improves its dynamics performance.

  20. Controlling the Casimir force via the electromagnetic properties of materials

    International Nuclear Information System (INIS)

    Yang Yaping; Chen Hong; Zeng Ran; Zhu Shiyao; Zubairy, M. Suhail

    2010-01-01

    The control of the Casimir force between two parallel plates can be achieved through adjusting the frequency-dependent electromagnetic properties of materials of the two plates. We show that, for different plate separations, the main contribution to the Casimir force comes from different frequency regions: For smaller (larger) separation, it comes from the higher (lower) frequency region. When the separation of the plates increases, the Casimir force can vary from attractive to repulsive and/or vice versa, by selecting the two plates with suitable electromagnetic properties. We discuss how a restoring Casimir force, which varies from repulsive to attractive by increasing the separation, can be realized and that the stable equilibrium is formed at zero Casimir force.

  1. Coherence and interlimb force control: Effects of visual gain.

    Science.gov (United States)

    Kang, Nyeonju; Cauraugh, James H

    2018-03-06

    Neural coupling across hemispheres and homologous muscles often appears during bimanual motor control. Force coupling in a specific frequency domain may indicate specific bimanual force coordination patterns. This study investigated coherence on pairs of bimanual isometric index finger force while manipulating visual gain and task asymmetry conditions. We used two visual gain conditions (low and high gain = 8 and 512 pixels/N), and created task asymmetry by manipulating coefficient ratios imposed on the left and right index finger forces (0.4:1.6; 1:1; 1.6:0.4, respectively). Unequal coefficient ratios required different contributions from each hand to the bimanual force task resulting in force asymmetry. Fourteen healthy young adults performed bimanual isometric force control at 20% of their maximal level of the summed force of both fingers. We quantified peak coherence and relative phase angle between hands at 0-4, 4-8, and 8-12 Hz, and estimated a signal-to-noise ratio of bimanual forces. The findings revealed higher peak coherence and relative phase angle at 0-4 Hz than at 4-8 and 8-12 Hz for both visual gain conditions. Further, peak coherence and relative phase angle values at 0-4 Hz were larger at the high gain than at the low gain. At the high gain, higher peak coherence at 0-4 Hz collapsed across task asymmetry conditions significantly predicted greater signal-to-noise ratio. These findings indicate that a greater level of visual information facilitates bimanual force coupling at a specific frequency range related to sensorimotor processing. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Mercury Specie and Multi-Pollutant Control

    Energy Technology Data Exchange (ETDEWEB)

    Rob James; Virgil Joffrion; John McDermott; Steve Piche

    2010-05-31

    This project was awarded to demonstrate the ability to affect and optimize mercury speciation and multi-pollutant control using non-intrusive advanced sensor and optimization technologies. The intent was to demonstrate plant-wide optimization systems on a large coal fired steam electric power plant in order to minimize emissions, including mercury (Hg), while maximizing efficiency and maintaining saleable byproducts. Advanced solutions utilizing state-of-the-art sensors and neural network-based optimization and control technologies were proposed to maximize the removal of mercury vapor from the boiler flue gas thereby resulting in lower uncontrolled releases of mercury into the atmosphere. Budget Period 1 (Phase I) - Included the installation of sensors, software system design and establishment of the as-found baseline operating metrics for pre-project and post-project data comparison. Budget Period 2 (Phase II) - Software was installed, data communications links from the sensors were verified, and modifications required to integrate the software system to the DCS were performed. Budget Period 3 (Phase III) - Included the validation and demonstration of all control systems and software, and the comparison of the optimized test results with the targets established for the project site. This report represents the final technical report for the project, covering the entire award period and representing the final results compared to project goals. NeuCo shouldered 61% of the total project cost; while DOE shouldered the remaining 39%. The DOE requires repayment of its investment. This repayment will result from commercial sales of the products developed under the project. NRG's Limestone power plant (formerly owned by Texas Genco) contributed the host site, human resources, and engineering support to ensure the project's success.

  3. Active control of multi-input hydraulic journal bearing system

    Science.gov (United States)

    Chuang, Jen-Chen; Chen, Chi-Yin; Tu, Jia-Ying

    2016-09-01

    Because of the advantages of high accuracy, high capacity, and low friction, the development of hydrostatic bearing for machine tool receives significant attention in the last decades. The mechanics and mechanical design of hydrostatic journal bearing with capillary restrictors has been discussed in literature. However, pragmatically, the undesired loading effects of cutting force tend to result in resonance and instability of the rotor and damage the shaft during operation. Therefore, multi-input, active flow control using state feedback design is proposed in this paper. To this purpose, the proportional pressure valves are added to the hydraulic system as active control devices, and the linearised models of the bearing and valve are discussed and identified. Simulation and experimental work is conducted to verify the proposed active control and parameter identification techniques. The results show that the unbalance responses of the rotor are reduced by the proposed state feedback controller, which is able to regulate the flow pressure effectively, thus enhancing the stability and accuracy of the hydraulic journal bearing.

  4. Control of weakly conductive fluids by near wall Lorentz forces

    Energy Technology Data Exchange (ETDEWEB)

    Hinze, M. [Technische Univ. Dresden (Germany). Inst. fuer Numerische Mathematik

    2007-07-01

    In this work optimal and model-predictive control approaches for control of weakly conductive fluids are developed. The flow around the circular cylinder at low Reynolds numbers serves as prototyping application. Control by near-wall Lorentz forces gains either to suppress the formation of the von Karman Vortex Street, or to reduce the drag. Besides a concise mathematical modelling numerical examples are presented which highlight the scope of the presented control approaches. (orig.)

  5. Modeling and boundary force control of microcantilevers utilized in atomic force microscopy for cellular imaging and characterization

    Science.gov (United States)

    Eslami, Sohrab

    This dissertation undertakes the theoretical and experimental developments microcantilevers utilized in Atomic Force Microscopy (AFM) with applications to cellular imaging and characterization. The capability of revealing the inhomogeneties or interior of ultra-small materials has been of most interest to many researchers. However, the fundamental concept of signal and image formation remains unexplored and not fully understood. For his, a semi-empirical nonlinear force model is proposed to show that virtual frequency generation, regarded as the simplest synthesized subsurface probe, occurs optimally when the force is tuned to the van der Waals form. This is the first-time observation of a novel theoretical dynamic multi-frequency force microscopy that has not been already reported. Owing to the broad applications of microcantilevers in the nanoscale imaging and microscopic techniques, there is an essential feeling to study and propose a comprehensive model of such systems. Therefore, in the theoretical part of this dissertation, a distributed-parameters representation modeling of the microcantilever along with a general interaction force comprising of two attractive and repulsive components with general amplitude and power terms is studied. This model is investigated in a general 2D Cartesian coordinate to consider the motions of the probe with a tip mass. There is an excitation at the microcantilever's base such that the end of the beam is subject to the proposed general force. These forces are very sensitive to the amplitude and power terms of these parts; on the other hand, atomic intermolecular force is a function of the distance such that this distance itself is also a function of the interaction force that will result in a nonlinear implicit equation. From a parametric study in the probe-sample excitation, it is shown that the predicted behavior of the generated difference-frequency oscillation amplitude agrees well with experimental measurements. Following

  6. Multiple-state based power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-01-01

    Full Text Available Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in wireless mesh networks (WMNs). In this paper, we present asynchronous multiple-state based power control for MRMC WMNs. First, WMN is represented as a set of disjoint...

  7. Range based power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-08-01

    Full Text Available Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in Wireless Mesh Networks (WMNs). In this paper, researchers present a range based dynamic power control for MRMC WMNs. First, WMN is represented as a set of disjoint Unified...

  8. Report of the Material Control and Material Accounting Task Force

    International Nuclear Information System (INIS)

    1978-03-01

    In September 1977 a Task Force was formed to complete a study of the role of material control and material accounting in NRC's safeguards program. The Task Force's assignment was to: define the roles and objectives of material control and material accounting in the NRC safeguards program; recommend goals for the material control and material accounting systems based on their roles and objectives; assess the extent to which the existing safeguards regulatory base meets or provides the capability to meet the recommended goals; and provide direction for material control and material accounting development, including both near-term and long-term upgrades. The study was limited to domestic nuclear facilities possessing significant amounts of plutonium, uranium-233 or highly enriched uranium in unsealed form. The Task Force findings are reported

  9. Myoelectric hand prosthesis force control through servo motor current feedback.

    Science.gov (United States)

    Sono, Tálita Saemi Payossim; Menegaldo, Luciano Luporini

    2009-10-01

    This paper presents the prehension force closed-loop control design of a mechanical finger commanded by electromyographic signal (EMG) from a patient's arm. The control scheme was implemented and tested in a mechanical finger prototype with three degrees of freedom and one actuator, driven by arm muscles EMG of normal volunteers. Real-time indirect estimation of prehension force was assessed by measuring the DC servo motor actuator current. A model of the plant comprising finger, motor, and grasped object was proposed. Model parameters were identified experimentally and a classical feedback phase-lead compensator was designed. The controlled mechanical finger was able to provide a more accurate prehension force modulation of a compliant object when compared to open-loop control.

  10. Optimal integral force feedback for active vibration control

    Science.gov (United States)

    Teo, Yik R.; Fleming, Andrew J.

    2015-11-01

    This paper proposes an improvement to Integral Force Feedback (IFF), which is a popular method for active vibration control of structures and mechanical systems. Benefits of IFF include robustness, guaranteed stability and simplicity. However, the maximum damping performance is dependent on the stiffness of the system; hence, some systems cannot be adequately controlled. In this paper, an improvement to the classical force feedback control scheme is proposed. The improved method achieves arbitrary damping for any mechanical system by introducing a feed-through term. The proposed improvement is experimentally demonstrated by actively damping an objective lens assembly for a high-speed confocal microscope.

  11. Multi-Objective Nonlinear Model Predictive Control: Lexicographic Method

    OpenAIRE

    Zheng, Tao; Wu, Gang; Liu, Guang-Hong; Ling, Qing

    2010-01-01

    In this chapter, to avoid the disadvantages of weight coefficients in multi-objective dynamic optimization, lexicographic (completely stratified) and partially stratified frameworks of multi-objective controller are proposed. The lexicographic framework is absolutely prioritydriven and the partially stratified framework is a modification of it, they both can solve the multi-objective control problem with the concept of priority for objective’s relative importance, while the latter one is mo...

  12. A study of estimating cutting depth for multi-pass nanoscale cutting by using atomic force microscopy

    International Nuclear Information System (INIS)

    Lin, Zone-Ching; Hsu, Ying-Chih

    2012-01-01

    This paper studies two models for estimating cutting depth of multi-pass nanoscale cutting by using an atomic force microscopy (AFM) probe. One estimates cutting depth for multi-pass nanoscale cutting by using regression equations of nanoscale contact pressure factor (NCP factor) while the other uses equation of specific down force energy (SDFE). This paper proposes taking a diamond-coated probe of AFM as the cutting tool to carry out multi-pass nanoscale cutting experiments on the surface of sapphire substrate. In the process of experimentation, different down forces are set, and the probe shape of AFM is known, then using each down force to multi-pass cutting the sapphire substrate. From the measured experimental data of a central cutting depth of the machining groove by AFM, this paper calculates the specific down force energy of each down force. The experiment results reveal that the specific down force energy of each case of multi-pass nanoscale cutting for different down forces under a probe of AFM is close to a constant value. This paper also compares the nanoscale cutting results from estimating cutting depths for each pass of multi-pass among the experimental results and the calculating results obtained by the two theories models. It is found that the model of specific down force energy can calculate cutting depths for each nanoscale cutting pass by one equation. It is easier to use than the multi-regression equations of the nanoscale contact pressure factor. Besides, the estimations of cutting depth results obtained by the model of specific down force energy are closer to that of the experiment results. It shows that the proposed specific down force energy model in this paper is an acceptable model.

  13. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    Science.gov (United States)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-05-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate.

  14. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    International Nuclear Information System (INIS)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-01-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate. (paper)

  15. Distributed Control in Multi-Vehicle Systems

    Directory of Open Access Journals (Sweden)

    Paul A. Avery

    2013-12-01

    Full Text Available The Southwest Research Institute (SwRI Mobile Autonomous Robotics Technology Initiative (MARTI program has enabled the development of fully-autonomous passenger-sized commercial vehicles and military tactical vehicles, as well as the development of cooperative vehicle behaviors, such as cooperative sensor sharing and cooperative convoy operations. The program has also developed behaviors to interface intelligent vehicles with intelligent road-side devices. The development of intelligent vehicle behaviors cannot be approached as stand-alone phenomena; rather, they must be understood within a context of the broader traffic system dynamics. The study of other complex systems has shown that system-level behaviors emerge as a result of the spatio-temporal dynamics within a system's constituent parts. The design of such systems must therefore account for both the system-level emergent behavior, as well as behaviors of individuals within the system. It has also become clear over the past several years, for both of these domains, that human trust in the behavior of individual vehicles is paramount to broader technology adoption. This paper examines the interplay between individual vehicle capabilities, vehicle connectivity, and emergent system behaviors, and presents some considerations for a distributed control paradigm in a multi-vehicle system.

  16. Concurrent Learning of Control in Multi agent Sequential Decision Tasks

    Science.gov (United States)

    2018-04-17

    Concurrent Learning of Control in Multi-agent Sequential Decision Tasks The overall objective of this project was to develop multi-agent reinforcement... learning (MARL) approaches for intelligent agents to autonomously learn distributed control policies in decentral- ized partially observable... learning of policies in Dec-POMDPs, established performance bounds, evaluated these algorithms both theoretically and empirically, The views

  17. Electrotactile EMG feedback improves the control of prosthesis grasping force

    Science.gov (United States)

    Schweisfurth, Meike A.; Markovic, Marko; Dosen, Strahinja; Teich, Florian; Graimann, Bernhard; Farina, Dario

    2016-10-01

    Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for

  18. Accurate fluid force measurement based on control surface integration

    Science.gov (United States)

    Lentink, David

    2018-01-01

    Nonintrusive 3D fluid force measurements are still challenging to conduct accurately for freely moving animals, vehicles, and deforming objects. Two techniques, 3D particle image velocimetry (PIV) and a new technique, the aerodynamic force platform (AFP), address this. Both rely on the control volume integral for momentum; whereas PIV requires numerical integration of flow fields, the AFP performs the integration mechanically based on rigid walls that form the control surface. The accuracy of both PIV and AFP measurements based on the control surface integration is thought to hinge on determining the unsteady body force associated with the acceleration of the volume of displaced fluid. Here, I introduce a set of non-dimensional error ratios to show which fluid and body parameters make the error negligible. The unsteady body force is insignificant in all conditions where the average density of the body is much greater than the density of the fluid, e.g., in gas. Whenever a strongly deforming body experiences significant buoyancy and acceleration, the error is significant. Remarkably, this error can be entirely corrected for with an exact factor provided that the body has a sufficiently homogenous density or acceleration distribution, which is common in liquids. The correction factor for omitting the unsteady body force, {{{ {ρ f}} {1 - {ρ f} ( {{ρ b}+{ρ f}} )}.{( {{{{ρ }}b}+{ρ f}} )}}} , depends only on the fluid, {ρ f}, and body, {{ρ }}b, density. Whereas these straightforward solutions work even at the liquid-gas interface in a significant number of cases, they do not work for generalized bodies undergoing buoyancy in combination with appreciable body density inhomogeneity, volume change (PIV), or volume rate-of-change (PIV and AFP). In these less common cases, the 3D body shape needs to be measured and resolved in time and space to estimate the unsteady body force. The analysis shows that accounting for the unsteady body force is straightforward to non

  19. Magnetic particle separation using controllable magnetic force switches

    International Nuclear Information System (INIS)

    Wei Zunghang; Lee, C.-P.; Lai, M.-F.

    2010-01-01

    Magnetic particle separation is very important in biomedical applications. In this study, a magnetic particle microseparator is proposed that uses micro magnets to produce open/closed magnetic flux for switching on/off the separation. When all magnets are magnetized in the same direction, the magnetic force switch for separation is on; almost all magnetic particles are trapped in the channel side walls and the separation rate can reach 95%. When the magnetization directions of adjacent magnets are opposite, the magnetic force switch for separation is off, and most magnetic particles pass through the microchannel without being trapped. For the separation of multi-sized magnetic particles, the proposed microseparator is numerically demonstrated to have high separation rate.

  20. High cable forces deteriorate pinch force control in voluntary-closing body-powered prostheses

    NARCIS (Netherlands)

    Hichert, M.; Abbink, D.A.; Kyberd, P.J.; Plettenburg, D.H.

    2017-01-01

    Background It is generally asserted that reliable and intuitive control of upper-limb prostheses requires adequate feedback of prosthetic finger positions and pinch forces applied to objects. Bodypowered prostheses (BPPs) provide the user with direct proprioceptive feedback. Currently available

  1. Formation Control of Robotic Swarm Using Bounded Artificial Forces

    Science.gov (United States)

    Zha, Yabing; Peng, Yong

    2013-01-01

    Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions. PMID:24453809

  2. Formation Control of Robotic Swarm Using Bounded Artificial Forces

    Directory of Open Access Journals (Sweden)

    Long Qin

    2013-01-01

    Full Text Available Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions.

  3. Formation control of robotic swarm using bounded artificial forces.

    Science.gov (United States)

    Qin, Long; Zha, Yabing; Yin, Quanjun; Peng, Yong

    2013-01-01

    Formation control of multirobot systems has drawn significant attention in the recent years. This paper presents a potential field control algorithm, navigating a swarm of robots into a predefined 2D shape while avoiding intermember collisions. The algorithm applies in both stationary and moving targets formation. We define the bounded artificial forces in the form of exponential functions, so that the behavior of the swarm drove by the forces can be adjusted via selecting proper control parameters. The theoretical analysis of the swarm behavior proves the stability and convergence properties of the algorithm. We further make certain modifications upon the forces to improve the robustness of the swarm behavior in the presence of realistic implementation considerations. The considerations include obstacle avoidance, local minima, and deformation of the shape. Finally, detailed simulation results validate the efficiency of the proposed algorithm, and the direction of possible futrue work is discussed in the conclusions.

  4. Topology Control in Aerial Multi-Beam Directional Networks

    Science.gov (United States)

    2017-04-24

    Topology Control in Aerial Multi-Beam Directional Networks Brian Proulx, Nathaniel M. Jones, Jennifer Madiedo, Greg Kuperman {brian.proulx, njones...significant interference. Topology control (i.e., selecting a subset of neighbors to communicate with) is vital to reduce the interference. Good topology ...underlying challenges to topology control in multi-beam direction networks. Two topology control algorithms are developed: a centralized algorithm

  5. ASSESSMENT OF GRIP FORCE CONTROL IN PATIENTS WITH MUSCULAR DYSTROPHY

    Directory of Open Access Journals (Sweden)

    Gregorij Kurillo

    2004-12-01

    Full Text Available Background. The majority of hand functionality tests are based on qualitative assessment which largely depends on the experience of the therapist. Computer-assisted methods can provide more objective and accurate measurements of the grip force and other parameters related to grasping.Methods. We analysed the grip force control in 12 patients with muscular dystrophy using the tracking system developed. The system consists of a grip-measuring device with endobjects assessing the force applied in different grips. The device was used as input to a tracking task where the patient applied the grip force according to the visual feedback from the computer screen. Each patient performed two tasks which consisted of tracking a ramp and sinus target.Results. We analysed the maximal grip force as assessed in the ramp task and the tracking accuracy of the sinus task. The results are compared among five different grips (cylindrical, lateral, palmar, pinch and spherical grip, applied with dominant and non-dominant hand. The results show no significant difference in tracking accuracy between the dominant and non-dominant hand.Conclusions. The results obtained in tracking the ramp target showed that the method could be used for the assessment of the muscle fatigue, providing quantitative information on muscle capacity. The results of the sinus-tracking task showed that the method can evaluate the grip force control in different types of grips, providing information on hand dexterity, muscle activation patterns or tremor.

  6. Customization, control, and characterization of a commercial haptic device for high-fidelity rendering of weak forces.

    Science.gov (United States)

    Gurari, Netta; Baud-Bovy, Gabriel

    2014-09-30

    The emergence of commercial haptic devices offers new research opportunities to enhance our understanding of the human sensory-motor system. Yet, commercial device capabilities have limitations which need to be addressed. This paper describes the customization of a commercial force feedback device for displaying forces with a precision that exceeds the human force perception threshold. The device was outfitted with a multi-axis force sensor and closed-loop controlled to improve its transparency. Additionally, two force sensing resistors were attached to the device to measure grip force. Force errors were modeled in the frequency- and time-domain to identify contributions from the mass, viscous friction, and Coulomb friction during open- and closed-loop control. The effect of user interaction on system stability was assessed in the context of a user study which aimed to measure force perceptual thresholds. Findings based on 15 participants demonstrate that the system maintains stability when rendering forces ranging from 0-0.20 N, with an average maximum absolute force error of 0.041 ± 0.013 N. Modeling the force errors revealed that Coulomb friction and inertia were the main contributors to force distortions during respectively slow and fast motions. Existing commercial force feedback devices cannot render forces with the required precision for certain testing scenarios. Building on existing robotics work, this paper shows how a device can be customized to make it reliable for studying the perception of weak forces. The customized and closed-loop controlled device is suitable for measuring force perceptual thresholds. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Obesity-related differences in neural correlates of force control.

    Science.gov (United States)

    Mehta, Ranjana K; Shortz, Ashley E

    2014-01-01

    Greater body segment mass due to obesity has shown to impair gross and fine motor functions and reduce balance control. While recent studies suggest that obesity may be linked with altered brain functions involved in fine motor tasks, this association is not well investigated. The purpose of this study was to examine the neural correlates of motor performance in non-obese and obese adults during force control of two upper extremity muscles. Nine non-obese and eight obese young adults performed intermittent handgrip and elbow flexion exertions at 30% of their respective muscle strengths for 4 min. Functional near infrared spectroscopy was employed to measure neural activity in the prefrontal cortex bilaterally, joint steadiness was computed using force fluctuations, and ratings of perceived exertions (RPEs) were obtained to assess perceived effort. Obesity was associated with higher force fluctuations and lower prefrontal cortex activation during handgrip exertions, while RPE scores remained similar across both groups. No obesity-related differences in neural activity, force fluctuation, or RPE scores were observed during elbow flexion exertions. The study is one of the first to examine obesity-related differences on prefrontal cortex activation during force control of the upper extremity musculature. The study findings indicate that the neural correlates of motor activity in the obese may be muscle-specific. Future work is warranted to extend the investigation to monitoring multiple motor-function related cortical regions and examining obesity differences with different task parameters (e.g., longer duration, increased precision demands, larger muscles, etc.).

  8. Semi-quartic force fields retrieved from multi-mode expansions: Accuracy, scaling behavior, and approximations

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Raghunathan [Institute of Physical Chemistry and National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Rauhut, Guntram, E-mail: rauhut@theochem.uni-stuttgart.de [Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

    2015-04-21

    Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-Oppenheimer potential energy surface (PES) and are frequently used within the calculation of anharmonic vibrational frequencies based on 2nd order vibrational perturbation theory (VPT2). As such they are usually determined by differentiation of the electronic energy with respect to the nuclear coordinates. Alternatively, potential energy surfaces can be expanded in terms of multi-mode expansions, which typically do not require any derivative techniques. The computational effort to retrieve QFF from size-reduced multi-mode expansions has been studied and has been compared with standard Taylor-expansions. As multi-mode expansions allow for the convenient introduction of subtle approximations, these will be discussed in some detail. In addition, a preliminary study about the applicability of a generalized Duschinsky transformation to QFFs is provided. This transformation allows for the efficient evaluation of VPT2 frequencies of isotopologues from the PES of the parent compound and thus avoids the recalculation of PESs in different axes systems.

  9. Geometric Aspects of Force Controllability for a Swimming Model

    International Nuclear Information System (INIS)

    Khapalov, A. Y.

    2008-01-01

    We study controllability properties (swimming capabilities) of a mathematical model of an abstract object which 'swims' in the 2-D Stokes fluid. Our goal is to investigate how the geometric shape of this object affects the forces acting upon it. Such problems are of interest in biology and engineering applications dealing with propulsion systems in fluids

  10. Vibration control of an elastic strip by a singular force

    Indian Academy of Sciences (India)

    strip are changed by applying a lateral concentrated force to the plate. ... Predicting resonance frequency of plates is an important technological and scientific ... Ritz methods in a number of studies pertaining to control of flutter in aerospace ..... Bingham B, Atalla M J, Hagood N W 2001 Comparison of structural-acoustic ...

  11. Controlling propulsive forces in gait initiation in transfemoral amputees

    NARCIS (Netherlands)

    van Keeken, Helco G.; Vrieling, Aline H.; Hof, At L.; Halbertsma, Jan P. K.; Schoppen, Tanneke; Postema, Klaas; Otten, Bert

    During prosthetic gait initiation, transfemoral (TF) amputees control the spatial and temporal parameters that modulate the propulsive forces, the positions of the center of pressure (CoP), and the center of mass (CoM). Whether their sound leg or the prosthetic leg is leading, the TF amputees reach

  12. Control of master-slave manipulator using virtual force

    International Nuclear Information System (INIS)

    Kosuge, Kazuhiro; Fukuda, Toshio; Itoh, Tomotaka; Sakamoto, Keizoh; Noma, Yasuo.

    1994-01-01

    We propose a control system for a master-slave manipulator system having a rate-controlled slave manipulator. In this system, the master manipulator is stiffness-controlled in the Cartesian coordinate system, and the slave manipulator is damping-controlled in the Cartesian coordinate system. The desired velocity of the slave arm is given by a displacement of the master arm from a nominal position. The operator feels virtual contact force from the environment because the contact force is proportional to the displacement when the slave arm motion is constrained by the environment. The proposed method is experimentally applied to manipulators with three degrees of freedom. The experimental results illustrate the validity of the proposed system. (author)

  13. Force-controlled patch clamp of beating cardiac cells.

    Science.gov (United States)

    Ossola, Dario; Amarouch, Mohamed-Yassine; Behr, Pascal; Vörös, János; Abriel, Hugues; Zambelli, Tomaso

    2015-03-11

    From its invention in the 1970s, the patch clamp technique is the gold standard in electrophysiology research and drug screening because it is the only tool enabling accurate investigation of voltage-gated ion channels, which are responsible for action potentials. Because of its key role in drug screening, innovation efforts are being made to reduce its complexity toward more automated systems. While some of these new approaches are being adopted in pharmaceutical companies, conventional patch-clamp remains unmatched in fundamental research due to its versatility. Here, we merged the patch clamp and atomic force microscope (AFM) techniques, thus equipping the patch-clamp with the sensitive AFM force control. This was possible using the FluidFM, a force-controlled nanopipette based on microchanneled AFM cantilevers. First, the compatibility of the system with patch-clamp electronics and its ability to record the activity of voltage-gated ion channels in whole-cell configuration was demonstrated with sodium (NaV1.5) channels. Second, we showed the feasibility of simultaneous recording of membrane current and force development during contraction of isolated cardiomyocytes. Force feedback allowed for a gentle and stable contact between AFM tip and cell membrane enabling serial patch clamping and injection without apparent cell damage.

  14. Models and control for force/torque sensors in robotics

    International Nuclear Information System (INIS)

    Johansson, Gert.

    1992-01-01

    One of the important problems in automatic assembly is the relative positioning accuracy between the parts in the assembly process. Inaccurate positions cause large insertion forces, wear and might damage the parts. They can also completely disable the assembly process. A solution to this problem is to detect the positioning error and to make a relevant adjustment of the position or path. This thesis presents a solution based on active feedback of force/torque data from a wrist mounted sensor. A task independent control algorithm has been realized through a sensor model concept. The sensor model includes an algorithm that transforms force/torque input to relevant motion of the end effector. The transformation is specified by a set of parameters e.g. desired forces, compliance and stopping criteria. The problem with gravity forces for varying end effector orientation is compensated by an algorithm, divided into three complexity levels. The compensation method includes a calibration sequence to ensure valid end effector properties to be used in the algorithm. A problem with available robot technology is bad integration possibilities for external sensors. To allow necessary modifications and expansions, an open and general control system architecture is proposed. The architecture is based in a computer workstation and transputers in pipeline for the robot specific operations. (au)

  15. Neuromechanical Control for Dynamic Bipedal Walking with Reduced Impact Forces

    DEFF Research Database (Denmark)

    Widenka, Johannes; Xiong, Xiaofeng; Matthias Braun, Jan

    2016-01-01

    Human walking emerges from an intricate interaction of nervous and musculoskeletal systems. Inspired by this principle, we integrate neural control and muscle-like mechanisms to achieve neuromechanical control of the biped robot RunBot. As a result, the neuromechanical controller enables RunBot t......Bot to perform more human-like walking and reduce impact force during walking, compared to original neural control. Moreover, it also generates adaptive joint motions of RunBot; thereby allowing it to deal with different terrains...

  16. Multi-Model Adaptive Fuzzy Controller for a CSTR Process

    Directory of Open Access Journals (Sweden)

    Shubham Gogoria

    2015-09-01

    Full Text Available Continuous Stirred Tank Reactors are intensively used to control exothermic reactions in chemical industries. It is a very complex multi-variable system with non-linear characteristics. This paper deals with linearization of the mathematical model of a CSTR Process. Multi model adaptive fuzzy controller has been designed to control the reactor concentration and temperature of CSTR process. This method combines the output of multiple Fuzzy controllers, which are operated at various operating points. The proposed solution is a straightforward implementation of Fuzzy controller with gain scheduler to control the linearly inseparable parameters of a highly non-linear process.

  17. Forced excitation and active control for the measurement of fluid-elastic forces

    International Nuclear Information System (INIS)

    Caillaud, Sebastien

    1999-01-01

    The action of a fluid flow on a tubes bundle is commonly decomposed into a random turbulent excitation and a fluid-elastic excitation. The fluid-elastic forces which are coupled to the tubes movement can be experimentally determined from an analysis of the vibratory response of the structure excited by turbulent forces. For low flow velocities, the turbulent excitation can be insufficient to make the tube significantly vibrate and to permit a correct vibratory analysis. On the opposite side, the structure can become unstable for high flow velocities: the fluid-elastic forces make the fluid-structure damping system fall towards zero. Two experimental methods are proposed in order to extend the considered flow rate. An additional excitation force allows to increase the tube vibration level for improving the signal-noise ratio at low velocities. When the tube is submitted to fluid-elastic instability, an artificial damping contribution by active control allows to stabilize it. Methods are implemented on a flexible tube inserted into rigid tubes bundle water and water-air transverse flows. Two actuator technologies are used: an electromagnetic exciter and piezoelectric actuators. The additional excitation method shows that the fluid-elastic forces remain insignificant at low velocity single phase flow. With the active control method, it is possible to carry out tests beyond the fluid-elastic instability. In two-phase flow, the stabilization of the structure is observed for low vacuum rates. The obtained new results are analyzed with the literature expected results in terms of fluid-elastic coupling and turbulent excitation. (author) [fr

  18. Optical network control plane for multi-domain networking

    DEFF Research Database (Denmark)

    Manolova, Anna Vasileva

    This thesis focuses on multi-domain routing for traffice engineering and survivability support in optical transport networks under the Generalized Multi-Protocol Label Switching (GMPLS) control framework. First, different extensions to the Border Gateway Protocol for multi-domain Traffic...... process are not enough for efficient TE in mesh multi-domain networks. Enhancing the protocol with multi-path dissemination capability, combined with the employment of an end-to-end TE metric proves to be a highly efficient solution. Simulation results show good performance characteristics of the proposed...... is not as essential for improved network performance as the length of the provided paths. Second, the issue of multi-domain survivability support is analyzed. An AS-disjoint paths is beneficial not only for resilience support, but also for facilitating adequate network reactions to changes in the network, which...

  19. Force control of a robot for surface contamination detection

    International Nuclear Information System (INIS)

    Petterson, B.J.; Jones, J.F.

    1987-01-01

    A system is under development at Sandia National Laboratories for use in understanding the issues relating to automated robotic handling of spent nuclear fuel shipping casks. The goal of robotic handling is reduction of personnel radiation exposure at the proposed geologic repositories. One of the major technology development areas has been the integration of sensors into the control of the robot system to allow operation in semi-structured environments. In particular, a multiaxis force sensor is used to make robot trajectory corrections based on the contact force between the robot and workpiece. This force feedback system allows contact swipes (smears) to be made on the cask surface in a repeatable manner. 8 refs., 3 figs

  20. Rate control and quality assurance during rhythmic force tracking.

    Science.gov (United States)

    Huang, Cheng-Ya; Su, Jyong-Huei; Hwang, Ing-Shiou

    2014-02-01

    Movement characteristics can be coded in the single neurons or in the summed activity of neural populations. However, whether neural oscillations are conditional to the frequency demand and task quality of rhythmic force regulation is still unclear. This study was undertaken to investigate EEG dynamics and behavior correlates during force-tracking at different target rates. Fourteen healthy volunteers conducted load-varying isometric abduction of the index finger by coupling the force output to sinusoidal targets at 0.5 Hz, 1.0 Hz, and 2.0 Hz. Our results showed that frequency demand significantly affected EEG delta oscillation (1-4 Hz) in the C3, CP3, CPz, and CP4 electrodes, with the greatest delta power and lowest delta peak around 1.5 Hz for slower tracking at 0.5 Hz. Those who had superior tracking congruency also manifested enhanced alpha oscillation (8-12 Hz). Alpha rhythms of the skilled performers during slow tracking spread through the whole target cycle, except for the phase of direction changes. However, the alpha rhythms centered at the mid phase of a target cycle with increasing target rate. In conclusion, our findings clearly suggest two advanced roles of cortical oscillation in rhythmic force regulation. Rate-dependent delta oscillation involves a paradigm shift in force control under different time scales. Phasic organization of alpha rhythms during rhythmic force tracking is related to behavioral success underlying the selective use of bimodal controls (feedback and feedforward processes) and the timing of attentional focus on the target's peak velocity. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Optimal feedback control of the forced van der Pol system

    International Nuclear Information System (INIS)

    Chagas, T.P.; Toledo, B.A.; Rempel, E.L.; Chian, A.C.-L.; Valdivia, J.A.

    2012-01-01

    A simple feedback control strategy for chaotic systems is investigated using the forced van der Pol system as an example. The strategy regards chaos control as an optimization problem, where the maximum magnitude Floquet multiplier of a target unstable periodic orbit (UPO) is used as a cost function that needs to be minimized. Thus, the method obtains the optimal control gain in terms of the stability of the target UPO. This strategy was recently proposed for the proportional feedback control (PFC) method. Here, it is extended to the highly popular delayed feedback control (DFC) method. Since the DFC method treats the system as a delay-differential equation whose phase space is infinite-dimensional, the characteristic multipliers are found through a truncation in the number of delayed states. Control of a target UPO is achieved for several values of the forcing amplitude. We compare the DFC and PFC methods in terms of stability of the controlled orbit, steady state error and control effort.

  2. Variations in Static Force Control and Motor Unit Behavior with Error Amplification Feedback in the Elderly

    Directory of Open Access Journals (Sweden)

    Yi-Ching Chen

    2017-11-01

    Full Text Available Error amplification (EA feedback is a promising approach to advance visuomotor skill. As error detection and visuomotor processing at short time scales decline with age, this study examined whether older adults could benefit from EA feedback that included higher-frequency information to guide a force-tracking task. Fourteen young and 14 older adults performed low-level static isometric force-tracking with visual guidance of typical visual feedback and EA feedback containing augmented high-frequency errors. Stabilogram diffusion analysis was used to characterize force fluctuation dynamics. Also, the discharge behaviors of motor units and pooled motor unit coherence were assessed following the decomposition of multi-channel surface electromyography (EMG. EA produced different behavioral and neurophysiological impacts on young and older adults. Older adults exhibited inferior task accuracy with EA feedback than with typical visual feedback, but not young adults. Although stabilogram diffusion analysis revealed that EA led to a significant decrease in critical time points for both groups, EA potentiated the critical point of force fluctuations <ΔFc2>, short-term effective diffusion coefficients (Ds, and short-term exponent scaling only for the older adults. Moreover, in older adults, EA added to the size of discharge variability of motor units and discharge regularity of cumulative discharge rate, but suppressed the pooled motor unit coherence in the 13–35 Hz band. Virtual EA alters the strategic balance between open-loop and closed-loop controls for force-tracking. Contrary to expectations, the prevailing use of closed-loop control with EA that contained high-frequency error information enhanced the motor unit discharge variability and undermined the force steadiness in the older group, concerning declines in physiological complexity in the neurobehavioral system and the common drive to the motoneuronal pool against force destabilization.

  3. Experimental Study of Multi-Walled Composite Shell Fragments under Thermal Force Effects

    Directory of Open Access Journals (Sweden)

    L. P. Tairova

    2015-01-01

    Full Text Available Multi-walled composite shells are a relatively new prospective type of load carrying structures for rocket and space engineering. These CFRP structures are produced by injection and infusion methods and have several advantages in comparison with common structures such as stringer-frame, grid and sandwich structures with a light core. In particular, those have more structural parameters, which enable one to control mechanical properties of the structure, and this is important in designing the load carrying structures of different purpose.Presently, there are few national and foreign publications on experimental investigations of mechanical properties of multi-walled shells. That is why the objective of the paper is to conduct the experimental study of deformation and failure processes of a multi-walled panel both under steady-state heating and under unsteady-state one.The paper presents the results of two tests: (1 the study of deformation and failure modes under compression and complete heating up to a specified temperature and (2 validation of working capability of multi-walled samples under single-side heating and compression simulating a start and flight version of the “ Proton” launch vehicle.Experimental results have shown that average elastic properties of multi-walled samples slightly depend on temperature for the studied range (from room temperature up to 195C while strength properties considerably decrease with increasing temperature, and this is typical for CFRP structures under compression. However, under unsteady-state short-term heating the structure has a strength that exceeds the minimal necessary strength of load carrying structures of the “Proton” launch vehicle (the samples satisfy simulated start conditions of the “Proton” launch vehicle. This is because of a low heat conductivity of the multi-walled core: an unheated sheet holds a low temperature and high load carrying capacity.Obtained results can be used in

  4. Implementation method of multi-terminal DC control system

    Science.gov (United States)

    Yi, Liu; Hao-Ran, Huang; Jun-Wen, Zhou; Hong-Guang, Guo; Yu-Yong, Zhou

    2018-04-01

    Currently the multi-terminal DC system (MTDC) has more stations. Each station needs operators to monitor and control the device. It needs much more operation and maintenance, low efficiency and small reliability; for the most important reason, multi-terminal DC system has complex control mode. If one of the stations has some problem, the control of the whole system should have problems. According to research of the characteristics of multi-terminal DC (VSC-MTDC) systems, this paper presents a strong implementation of the multi-terminal DC Supervisory Control and Data Acquisition (SCADA) system. This system is intelligent, can be networking, integration and intelligent. A master control system is added in each station to communication with the other stations to send current and DC voltage value to pole control system for each station. Based on the practical application and information feedback in the China South Power Grid research center VSC-MTDC project, this system is higher efficiency and save the cost on the maintenance of convertor station to improve the intelligent level and comprehensive effect. And because of the master control system, a multi-terminal system hierarchy coordination control strategy is formed, this make the control and protection system more efficiency and reliability.

  5. Elephant overflows: Multi-annual variability in Weddell Sea Deep Water driven by surface forcing

    Science.gov (United States)

    Meijers, Andrew; Meredith, Michael; Abrahamsen, Povl; Naviera-Garabato, Alberto; Ángel Morales Maqueda, Miguel; Polzin, Kurt

    2015-04-01

    The volume of the deepest and densest water mass in Drake Passage, Lower Weddell Sea Deep Water (LWSDW), is shown to have been decreasing over the last 20 years of observations, with an associated reduction in density driven by freshening. Superimposed on this long term trend is a multi-annual oscillation with a period of 3-5 years. This variability only appears in Drake Passage; observations in the east of the Scotia Sea show a similar long term trend, but with no apparent multi-annual variability. Clues as to the source of this variability may be found on the continental slope at approximately 1000 m immediately north of Elephant Island on the northern tip of the Antarctic Peninsula. Here there is an intermittent westward flowing cold/fresh slope current whose volume and properties are strongly correlated with the LWSDW multi-annual variability, although leading the LWSDW by around one year. As the slope current and LWSDW are separated from each other both geographically and in water mass characteristics, their co-variability implies that they are responding to a common forcing, while the lag between deep LWSDW and shallow slope current provides information on the timescale of this response. A newly available high resolution temperature and salinity multi-year time series from the Elephant Island slope at 1000 m is compared with reanalysis and model derived surface fluxes, sea ice extent and wind stress. We find that there are strong positive relationships between the surface wind stress and heat flux over the shelf at the tip of the Antarctic Peninsula and the properties of the slope current at 1000 m on seasonal to annual timescales. We use tracer release experiments in the Southern Ocean State Estimate (SOSE) model to investigate the lag between the slope current and LWSDW timeseries and hypothesise that the observed multi-annual variability in both water masses is driven by surface forcing over the shelf and the overflow of modified water from the slope in

  6. Coordinated control of multi-axis tasks

    International Nuclear Information System (INIS)

    Mc Kinnon, G.M.; King, M.L.; Runnings, D.W.

    1987-01-01

    The use of manipulators and the development of manipulator technology has steadily increased in recent years. Consequently, teleoperation of the remote operation of a machine or piece of equipment has also increased. Typically, teleoperation is employed in situations where the environment is dangerous or too remote for humans to work. In space exploration with the use of dextrous manipulators, teleoperation has become a critical component. This paper describes tests carried out to evaluate three man-machine interfaces with two dextrous manipulators. The three interfaces were a master/slave system with force reflection, a master slave system without force reflection, and two six degree of freedom handcontrollers. Results indicated that task accuracy was superior with the handcontrollers

  7. Satellite Dynamic Damping via Active Force Control Augmentation

    Science.gov (United States)

    Varatharajoo, Renuganth

    2012-07-01

    An approach that incorporates the Active Force Control (AFC) technique into a conventional Proportional-Derivative (PD) controller is proposed for a satellite active dynamic damping towards a full attitude control. The AFC method has been established to facilitate a robust motion control of dynamical systems in the presence of disturbances, parametric uncertainties and changes that are commonly prevalent in the real-world environment. The usefulness of the method can be extended by introducing intelligent mechanisms to approximate the mass or inertia matrix of the dynamic system to trigger the compensation effect of the controller. AFC is a technique that relies on the appropriate estimation of the inertial or mass parameters of the dynamic system and the measurements of the acceleration and force signals induced by the system if practical implementation is ever considered. In AFC, it is shown that the system subjected to a number of disturbances remains stable and robust via the compensating action of the control strategy. We demonstrate that it is possible to design a spacecraft attitude feedback controller that will ensure the system dynamics set point remains unchanged even in the presence of the disturbances provided that the actual disturbances can be modeled effectively. In order to further facilitate this analysis, a combined energy and attitude control system (CEACS) is proposed as a model satellite attitude control actuator. All the governing equations are established and the proposed satellite attitude control architecture is made amenable to numerical treatments. The results show that the PD-AFC attitude damping performances are superiorly better than that of the solely PD type. It is also shown that the tunings of the AFC system gains are crucial to ensure a better attitude damping performance and this process is mandatory for AFC systems. Finally, the results demonstrate an important satellite dynamic damping enhancement capability using the AFC

  8. Adaptive fuzzy sliding-mode control for multi-input multi-output chaotic systems

    International Nuclear Information System (INIS)

    Poursamad, Amir; Markazi, Amir H.D.

    2009-01-01

    This paper describes an adaptive fuzzy sliding-mode control algorithm for controlling unknown or uncertain, multi-input multi-output (MIMO), possibly chaotic, dynamical systems. The control approach encompasses a fuzzy system and a robust controller. The fuzzy system is designed to mimic an ideal sliding-mode controller, and the robust controller compensates the difference between the fuzzy controller and the ideal one. The parameters of the fuzzy system, as well as the uncertainty bound of the robust controller, are tuned adaptively. The adaptive laws are derived in the Lyapunov sense to guarantee the asymptotic stability and tracking of the controlled system. The effectiveness of the proposed method is shown by applying it to some well-known chaotic systems.

  9. A Multiposture Locomotor Training Device with Force-Field Control

    Directory of Open Access Journals (Sweden)

    Jianfeng Sui

    2014-11-01

    Full Text Available This paper introduces a multiposture locomotor training device (MPLTD with a closed-loop control scheme based on joint angle feedback, which is able to overcome various difficulties resulting from mechanical vibration and the weight of trainer to achieve higher accuracy trajectory. By introducing the force-field control scheme used in the closed-loop control, the device can obtain the active-constrained mode including the passive one. The MPLTD is mainly composed of three systems: posture adjusting and weight support system, lower limb exoskeleton system, and control system, of which the lower limb exoskeleton system mainly includes the indifferent equilibrium mechanism with two degrees of freedom (DOF and the driving torque is calculated by the Lagrangian function. In addition, a series of experiments, the weight support and the trajectory accuracy experiment, demonstrate a good performance of mechanical structure and the closed-loop control.

  10. Distributed model based control of multi unit evaporation systems

    International Nuclear Information System (INIS)

    Yudi Samyudia

    2006-01-01

    In this paper, we present a new approach to the analysis and design of distributed control systems for multi-unit plants. The approach is established after treating the effect of recycled dynamics as a gap metric uncertainty from which a distributed controller can be designed sequentially for each unit to tackle the uncertainty. We then use a single effect multi-unit evaporation system to illustrate how the proposed method is used to analyze different control strategies and to systematically achieve a better closed-loop performance using a distributed model-based controller

  11. Organization of Multi-controller Interaction in Software Defined Networks

    Directory of Open Access Journals (Sweden)

    Sergey V. Morzhov

    2018-01-01

    Full Text Available Software Defined Networking (SDN is a promising paradigm for network management. It is a centralized network intelligence on a dedicated server, which runs network operating system, and is called SDN controller. It was assumed that such an architecture should have an improved network performance and monitoring. However, the centralized control architecture of the SDNs brings novel challenges to reliability, scalability, fault tolerance and interoperability. These problems are especially acute for large data center networks and can be solved by combining SDN controllers into clusters, called multi-controllers. Multi-controller architecture became very important for SDN-enabled networks nowadays. This paper gives a comprehensive overview of SDN multi-controller architectures. The authors review several most popular distributed controllers in order to indicate their strengths and weaknesses. They also investigate and classify approaches used. This paper explains in details the difference among various types of multi-controller architectures, the distribution method and the communication system. Furthermore, it provides already implemented architectures and some examples of architectures under consideration by describing their design, communication process, and performance results. In this paper, the authors show their own classification of multi-controllers and claim that, despite the existence of undeniable advantages, all reviewed controllers have serious drawbacks, which must be eliminated. These drawbacks hamper the development of multi-controllers and their widespread adoption in corporate networks. In the end, the authors conclude that now it is impossible to find a solution capable to solve all the tasks assigned to it adequately and fully. The article is published in the authors’ wording.

  12. Psychophysical testing of visual prosthetic devices: a call to establish a multi-national joint task force

    Science.gov (United States)

    Rizzo, Joseph F., III; Ayton, Lauren N.

    2014-04-01

    Recent advances in the field of visual prostheses, as showcased in this special feature of Journal of Neural Engineering , have led to promising results from clinical trials of a number of devices. However, as noted by these groups there are many challenges involved in assessing vision of people with profound vision loss. As such, it is important that there is consistency in the methodology and reporting standards for clinical trials of visual prostheses and, indeed, the broader vision restoration research field. Two visual prosthesis research groups, the Boston Retinal Implant Project (BRIP) and Bionic Vision Australia (BVA), have agreed to work cooperatively to establish a multi-national Joint Task Force. The aim of this Task Force will be to develop a consensus statement to guide the methods used to conduct and report psychophysical and clinical results of humans who receive visual prosthetic devices. The overarching goal is to ensure maximum benefit to the implant recipients, not only in the outcomes of the visual prosthesis itself, but also in enabling them to obtain accurate information about this research with ease. The aspiration to develop a Joint Task Force was first promulgated at the inaugural 'The Eye and the Chip' meeting in September 2000. This meeting was established to promote the development of the visual prosthetic field by applying the principles of inclusiveness, openness, and collegiality among the growing body of researchers in this field. These same principles underlie the intent of this Joint Task Force to enhance the quality of psychophysical research within our community. Despite prior efforts, a critical mass of interested parties could not congeal. Renewed interest for developing joint guidelines has developed recently because of a growing awareness of the challenges of obtaining reliable measurements of visual function in patients who are severely visually impaired (in whom testing is inherently noisy), and of the importance of

  13. A multi-axis MEMS sensor with integrated carbon nanotube-based piezoresistors for nanonewton level force metrology

    International Nuclear Information System (INIS)

    Cullinan, Michael A; Panas, Robert M; Culpepper, Martin L

    2012-01-01

    This paper presents the design and fabrication of a multi-axis microelectromechanical system (MEMS) force sensor with integrated carbon nanotube (CNT)-based piezoresistive sensors. Through the use of proper CNT selection and sensor fabrication techniques, the performance of the CNT-based MEMS force sensor was increased by approximately two orders of magnitude as compared to current CNT-based sensor systems. The range and resolution of the force sensor were determined as 84 μN and 5.6 nN, respectively. The accuracy of the force sensor was measured to be better than 1% over the device’s full range. (paper)

  14. Force Reflection Control for Master/Slave Tele-manipulators

    International Nuclear Information System (INIS)

    Kang, Min Sig; Kim, Doo Ho; Choi, Sun Il; Kim, Nam Hyung; Lee, Jong Bee

    2009-04-01

    This report concerns on a master/slave tele-manipulator which is used in highly hazardous hot cell. To design a force reflection and fine tracking control for the master-slave telemanipulator, the following has been carried out. (1) Variation of the moment of inertia of each link in the operating angle range, (2) Variation of the gratitational torque of each link in the operating angle range, (3) Dynamic characteristic analysis of the master-slave manipulator controlled by an output PD-control through a modal analysis, (4) Optimal static output feedback PD-control design by using modal analysis, (5) Controller design for each joint, (6) Adams-MatLab Simulink simulation model development. The results this project are as follows: (1) Program for analysis of the moment of inertia of each link in the operating angle range and simulation results, (2) Program for analysis of the gratitational torque of each link in the operating angle range and simulation results, (3) Dynamic characteristic of the master-slave manipulator controlled by an output PD-control through a modal analysis, (4) Program for designing optimal output PD-control by using modal analysis, (5) Controller designed for each joint, (6) Adams-MatLab Simulink simulation model, (7) Simulation results form output PD-control, etc

  15. FY1995 distributed control of man-machine cooperative multi agent systems; 1995 nendo ningen kyochogata multi agent kikai system no jiritsu seigyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In the near future, distributed autonomous systems will be practical in many situations, e.g., interactive production systems, hazardous environments, nursing homes, and individual houses. The agents which consist of the distributed system must not give damages to human being and should be working economically. In this project man-machine cooperative multi agent systems are studied in many kind of respects, and basic design technology, basic control technique are developed by establishing fundamental theories and by constructing experimental systems. In this project theoretical and experimental studies are conducted in the following sub-projects: (1) Distributed cooperative control in multi agent type actuation systems (2) Control of non-holonomic systems (3) Man-machine Cooperative systems (4) Robot systems learning human skills (5) Robust force control of constrained systems In each sub-project cooperative nature between machine agent systems and human being, interference between artificial multi agents and environment and new function emergence in coordination of the multi agents and the environment, robust force control against for the environments, control methods for non-holonomic systems, robot systems which can mimic and learn human skills were studied. In each sub-project, some problems were hi-lighted and solutions for the problems have been given based on construction of experimental systems. (NEDO)

  16. Development of the first force-controlled robot for otoneurosurgery.

    Science.gov (United States)

    Federspil, Philipp A; Geisthoff, Urban W; Henrich, Dominik; Plinkert, Peter K

    2003-03-01

    In some surgical specialties (eg, orthopedics), robots are already used in the operating room for bony milling work. Otological surgery and otoneurosurgery may also greatly benefit from the enhanced precision of robotics. Experimental study on robotic milling of oak wood and human temporal bone specimen. A standard industrial robot with a six-degrees-of-freedom serial kinematics was used, with force feedback to proportionally control the robot speed. Different milling modes and characteristic path parameters were evaluated to generate milling paths based on computer-aided design (CAD) geometry data of a cochlear implant and an implantable hearing system. The best-suited strategy proved to be the spiral horizontal milling mode with the burr held perpendicular to the temporal bone surface. To reduce groove height, the distance between paths should equal half the radius of the cutting burr head. Because of the vibration of the robot's own motors, a high oscillation of the SD of forces was encountered. This oscillation dropped drastically to nearly 0 Newton (N) when the burr head made contact with the dura mater, because of its damping characteristics. The cutting burr could be kept in contact with the dura mater for an extended period without damaging it, because of the burr's blunt head form. The robot moved the burr smoothly according to the encountered resistances. The study reports the first development of a functional robotic milling procedure for otoneurosurgery with force-based speed control. Future plans include implementation of ultrasound-based local navigation and performance of robotic mastoidectomy.

  17. Multi-scale forcing and the formation of subtropical desert and monsoon

    Directory of Open Access Journals (Sweden)

    G. X. Wu

    2009-09-01

    Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows. First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west. The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are located over the western

  18. Multi-scale forcing and the formation of subtropical desert and monsoon

    Directory of Open Access Journals (Sweden)

    G. X. Wu

    2009-09-01

    Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows.

    First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west.

    The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are

  19. Intelligent multi-unit disk controller

    International Nuclear Information System (INIS)

    Poirot, Lucien

    1982-01-01

    This controller has been designed as a link between a 16 bits minicomputer and two types of disks units interface: the SMD interface and an equivalent to the DRI unit interface. Four units of each type can be handled by the controller. A bit slice microprocessor controls the interface with the disks units. The maximum exchange rate is 8 megabits per second. A CRC feature has been provided for error detection. A 16 bits microprocessor implements the interface to the computer, assuring head positioning, the management of bad tracks, as well as the supervision of each transfer. A internal buffer memory allows an asynchronous dialogue with the computer. The implementation of the controller makes easy the adaptation to disks units of various types, and though it has been initially intended for a minicomputer of the MITRA type, its microprocessor based design makes it fitted to any minicomputer. (author) [fr

  20. Nonlinear force feedback control of piezoelectric-hydraulic pump actuator for automotive transmission shift control

    Science.gov (United States)

    Kim, Gi-Woo; Wang, K. W.

    2008-03-01

    In recent years, researchers have investigated the feasibility of utilizing piezoelectric-hydraulic pump based actuation systems for automotive transmission controls. This new concept could eventually reduce the complexity, weight, and fuel consumption of the current transmissions. In this research, we focus on how to utilize this new approach on the shift control of automatic transmissions (AT), which generally requires pressure profiling for friction elements during the operation. To illustrate the concept, we will consider the 1--> 2 up shift control using band brake friction elements. In order to perform the actuation force tracking for AT shift control, nonlinear force feedback control laws are designed based on the sliding mode theory for the given nonlinear system. This paper will describe the modeling of the band brake actuation system, the design of the nonlinear force feedback controller, and simulation and experimental results for demonstration of the new concept.

  1. Multi-control modes for a master-slave manipulator with different configurations and its maneuverability

    International Nuclear Information System (INIS)

    Matsuhira, Nobuto; Asakura, Makoto; Bamba, Hiroyuki

    1995-01-01

    The new master-slave control method is proposed on multi-control modes for a master-slave manipulator with different configurations. A virtual internal model following control is applied to position symmetrical bilateral control. In our method, a master-slave control mode (MS-mode), a joystick control mode (JS-mode), a master arm offset mode (OM-mode), and a servo hold mode (LK-mode) are able to be realized by operating the desired output values of the virtual internal models in a common control algorithm. There is compliant characteristic between the master and slave models. In the result of evaluation experiments between the MS-mode and the JS-mode, although the MS-mode is superior to the JS-mode in manipulating a fine task, our JS-mode is found to be useful to carry out such a task compared with a conventional JS-mode which only directs the rates for the slave arm. In the JS-mode, the slave arm moves to the position where the reaction force of the slave arm and the operating force of the master arm are balanced. Thus, it is possible either to control an overload for an object and to control the contact force. The validity of the proposed method is verified. (author)

  2. Robust multi-model predictive control of multi-zone thermal plate system

    Directory of Open Access Journals (Sweden)

    Poom Jatunitanon

    2018-02-01

    Full Text Available A modern controller was designed by using the mathematical model of a multi–zone thermal plate system. An important requirement for this type of controller is that it must be able to keep the temperature set-point of each thermal zone. The mathematical model used in the design was determined through a system identification process. The results showed that when the operating condition is changed, the performance of the controller may be reduced as a result of the system parameter uncertainties. This paper proposes a weighting technique of combining the robust model predictive controller for each operating condition into a single robust multi-model predictive control. Simulation and experimental results showed that the proposed method performed better than the conventional multi-model predictive control in rise time of transient response, when used in a system designed to work over a wide range of operating conditions.

  3. ANALYSIS of Control Force Grasping for a Multifunctional Five Fingered Robot to Pick-up Various of Components

    Directory of Open Access Journals (Sweden)

    Widhiada W.

    2016-01-01

    Full Text Available Multi-fingered robot gripper has become popular in the major research topics as grasping an object in robotic systems. The author considers a matter of style-based control model for a multi-fingered robot hand grasping an object with a known geometric characteristics. This paper introduces design process and analysis of contact force the five fingered gripper suitable to handle several of objects. The author applied Simulink/SimMechanics, Support package Arduino and Inventor software packages to facilatate and integrated the design of contact force gripper systems. The advance of PID control is used to control dynamics motions of the five fingered gripper systems. The multifunction finger’s gripper is developed to handle the various components. Contact force between fingertips and object surface is computed using the Hooke law concept. The analysis of experiment result shows the optimum of contact forces are achieved to hold the object. The spring and damper algorithm is used to compute the interaction of force between fingertips and object surface.

  4. Multi-segment foot kinematics and ground reaction forces during gait of individuals with plantar fasciitis.

    Science.gov (United States)

    Chang, Ryan; Rodrigues, Pedro A; Van Emmerik, Richard E A; Hamill, Joseph

    2014-08-22

    Clinically, plantar fasciitis (PF) is believed to be a result and/or prolonged by overpronation and excessive loading, but there is little biomechanical data to support this assertion. The purpose of this study was to determine the differences between healthy individuals and those with PF in (1) rearfoot motion, (2) medial forefoot motion, (3) first metatarsal phalangeal joint (FMPJ) motion, and (4) ground reaction forces (GRF). We recruited healthy (n=22) and chronic PF individuals (n=22, symptomatic over three months) of similar age, height, weight, and foot shape (p>0.05). Retro-reflective skin markers were fixed according to a multi-segment foot and shank model. Ground reaction forces and three dimensional kinematics of the shank, rearfoot, medial forefoot, and hallux segment were captured as individuals walked at 1.35 ms(-1). Despite similarities in foot anthropometrics, when compared to healthy individuals, individuals with PF exhibited significantly (pfoot kinematics and kinetics. Consistent with the theoretical injury mechanisms of PF, we found these individuals to have greater total rearfoot eversion and peak FMPJ dorsiflexion, which may put undue loads on the plantar fascia. Meanwhile, increased medial forefoot plantar flexion at initial contact and decreased propulsive GRF are suggestive of compensatory responses, perhaps to manage pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Radiative forcing and climate metrics for ozone precursor emissions: the impact of multi-model averaging

    Directory of Open Access Journals (Sweden)

    C. R. MacIntosh

    2015-04-01

    Full Text Available Multi-model ensembles are frequently used to assess understanding of the response of ozone and methane lifetime to changes in emissions of ozone precursors such as NOx, VOCs (volatile organic compounds and CO. When these ozone changes are used to calculate radiative forcing (RF (and climate metrics such as the global warming potential (GWP and global temperature-change potential (GTP there is a methodological choice, determined partly by the available computing resources, as to whether the mean ozone (and methane concentration changes are input to the radiation code, or whether each model's ozone and methane changes are used as input, with the average RF computed from the individual model RFs. We use data from the Task Force on Hemispheric Transport of Air Pollution source–receptor global chemical transport model ensemble to assess the impact of this choice for emission changes in four regions (East Asia, Europe, North America and South Asia. We conclude that using the multi-model mean ozone and methane responses is accurate for calculating the mean RF, with differences up to 0.6% for CO, 0.7% for VOCs and 2% for NOx. Differences of up to 60% for NOx 7% for VOCs and 3% for CO are introduced into the 20 year GWP. The differences for the 20 year GTP are smaller than for the GWP for NOx, and similar for the other species. However, estimates of the standard deviation calculated from the ensemble-mean input fields (where the standard deviation at each point on the model grid is added to or subtracted from the mean field are almost always substantially larger in RF, GWP and GTP metrics than the true standard deviation, and can be larger than the model range for short-lived ozone RF, and for the 20 and 100 year GWP and 100 year GTP. The order of averaging has most impact on the metrics for NOx, as the net values for these quantities is the residual of the sum of terms of opposing signs. For example, the standard deviation for the 20 year GWP is 2–3

  6. Force control of a tri-layer conducting polymer actuator using optimized fuzzy logic control

    International Nuclear Information System (INIS)

    Itik, Mehmet; Sabetghadam, Mohammadreza; Alici, Gursel

    2014-01-01

    Conducting polymers actuators (CPAs) are potential candidates for replacing conventional actuators in various fields, such as robotics and biomedical engineering, due to their advantageous properties, which includes their low cost, light weight, low actuation voltage and biocompatibility. As these actuators are very suitable for use in micro-nano manipulation and in injection devices in which the magnitude of the force applied to the target is of crucial importance, the force generated by CPAs needs to be accurately controlled. In this paper, a fuzzy logic (FL) controller with a Mamdani inference system is designed to control the blocking force of a trilayer CPA with polypyrrole electrodes, which operates in air. The particle swarm optimization (PSO) method is employed to optimize the controller’s membership function parameters and therefore enhance the performance of the FL controller. An adaptive neuro-fuzzy inference system model, which can capture the nonlinear dynamics of the actuator, is utilized in the optimization process. The optimized Mamdani FL controller is then implemented on the CPA experimentally, and its performance is compared with a non-optimized fuzzy controller as well as with those obtained from a conventional PID controller. The results presented indicate that the blocking force at the tip of the CPA can be effectively controlled by the optimized FL controller, which shows excellent transient and steady state characteristics but increases the control voltage compared to the non-optimized fuzzy controllers. (paper)

  7. Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

    Science.gov (United States)

    Clare, Frances C; Halder, Julia B; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S; Cunningham, Andrew A; Rowcliffe, Marcus; Garner, Trenton W J; Bosch, Jaime; Fisher, Matthew C

    2016-12-05

    Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

  8. Control of multi-machine using adaptive fuzzy

    Directory of Open Access Journals (Sweden)

    Bouchiba Bousmaha

    2011-01-01

    Full Text Available An indirect Adaptive fuzzy excitation control (IAFLC of power systems based on multi-input-multi-output linearization technique is developed in this paper. The power system considered in this paper consists of two generators and infinite bus connected through a network of transformers and transmission lines. The fuzzy controller is constructed from fuzzy feedback linearization controller whose parameters are adjusted indirectly from the estimates of plant parameters. The adaptation law adjusts the controller parameters on-line so that the plant output tracks the reference model output. Simulation results shown that the proposed controller IAFLC, compared with a controller based on tradition linearization technique can enhance the transient stability of the power system.

  9. Constant Cutting Force Control for CNC Machining Using Dynamic Characteristic-Based Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Hengli Liu

    2015-01-01

    Full Text Available This paper presents a dynamic characteristic-based fuzzy adaptive control algorithm (DCbFACA to avoid the influence of cutting force changing rapidly on the machining stability and precision. The cutting force is indirectly obtained in real time by monitoring and extraction of the motorized spindle current, the feed speed is fuzzy adjusted online, and the current was used as a feedback to control cutting force and maintain the machining process stable. Different from the traditional fuzzy control methods using the experience-based control rules, and according to the complex nonlinear characteristics of CNC machining, the power bond graph method is implemented to describe the dynamic characteristics of process, and then the appropriate variation relations are achieved between current and feed speed, and the control rules are optimized and established based on it. The numerical results indicated that DCbFACA can make the CNC machining process more stable and improve the machining precision.

  10. Dynamic simulation of knee-joint loading during gait using force-feedback control and surrogate contact modelling.

    Science.gov (United States)

    Walter, Jonathan P; Pandy, Marcus G

    2017-10-01

    The aim of this study was to perform multi-body, muscle-driven, forward-dynamics simulations of human gait using a 6-degree-of-freedom (6-DOF) model of the knee in tandem with a surrogate model of articular contact and force control. A forward-dynamics simulation incorporating position, velocity and contact force-feedback control (FFC) was used to track full-body motion capture data recorded for multiple trials of level walking and stair descent performed by two individuals with instrumented knee implants. Tibiofemoral contact force errors for FFC were compared against those obtained from a standard computed muscle control algorithm (CMC) with a 6-DOF knee contact model (CMC6); CMC with a 1-DOF translating hinge-knee model (CMC1); and static optimization with a 1-DOF translating hinge-knee model (SO). Tibiofemoral joint loads predicted by FFC and CMC6 were comparable for level walking, however FFC produced more accurate results for stair descent. SO yielded reasonable predictions of joint contact loading for level walking but significant differences between model and experiment were observed for stair descent. CMC1 produced the least accurate predictions of tibiofemoral contact loads for both tasks. Our findings suggest that reliable estimates of knee-joint loading may be obtained by incorporating position, velocity and force-feedback control with a multi-DOF model of joint contact in a forward-dynamics simulation of gait. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. Lumbar extensor muscle force control is associated with disability in people with chronic low back pain.

    Science.gov (United States)

    Pranata, Adrian; Perraton, Luke; El-Ansary, Doa; Clark, Ross; Fortin, Karine; Dettmann, Tim; Brandham, Robert; Bryant, Adam

    2017-07-01

    The ability to control lumbar extensor force output is necessary for daily activities. However, it is unknown whether this ability is impaired in chronic low back pain patients. Similarly, it is unknown whether lumbar extensor force control is related to the disability levels of chronic low back pain patients. Thirty-three chronic low back pain and 20 healthy people performed lumbar extension force-matching task where they increased and decreased their force output to match a variable target force within 20%-50% maximal voluntary isometric contraction. Force control was quantified as the root-mean-square-error between participants' force output and target force across the entire, during the increasing and decreasing portions of the force curve. Within- and between-group differences in force-matching error and the relationship between back pain group's force-matching results and their Oswestry Disability Index scores were assessed using ANCOVA and linear regression respectively. Back pain group demonstrated more overall force-matching error (mean difference=1.60 [0.78, 2.43], Pback pain group demonstrated more force-matching error while increasing than decreasing force output (mean difference=1.74, Pback pain group (R 2 =0.19, P=0.006). Lumbar extensor muscle force control is compromised in chronic low back pain patients. Force-matching error predicts disability, confirming the validity of our force control protocol for chronic low back pain patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Virtual grasping: closed-loop force control using electrotactile feedback.

    Science.gov (United States)

    Jorgovanovic, Nikola; Dosen, Strahinja; Djozic, Damir J; Krajoski, Goran; Farina, Dario

    2014-01-01

    Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously "unseen" objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

  13. Virtual Grasping: Closed-Loop Force Control Using Electrotactile Feedback

    Directory of Open Access Journals (Sweden)

    Nikola Jorgovanovic

    2014-01-01

    Full Text Available Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously “unseen” objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

  14. Deterministic methods for multi-control fuel loading optimization

    Science.gov (United States)

    Rahman, Fariz B. Abdul

    We have developed a multi-control fuel loading optimization code for pressurized water reactors based on deterministic methods. The objective is to flatten the fuel burnup profile, which maximizes overall energy production. The optimal control problem is formulated using the method of Lagrange multipliers and the direct adjoining approach for treatment of the inequality power peaking constraint. The optimality conditions are derived for a multi-dimensional multi-group optimal control problem via calculus of variations. Due to the Hamiltonian having a linear control, our optimal control problem is solved using the gradient method to minimize the Hamiltonian and a Newton step formulation to obtain the optimal control. We are able to satisfy the power peaking constraint during depletion with the control at beginning of cycle (BOC) by building the proper burnup path forward in time and utilizing the adjoint burnup to propagate the information back to the BOC. Our test results show that we are able to achieve our objective and satisfy the power peaking constraint during depletion using either the fissile enrichment or burnable poison as the control. Our fuel loading designs show an increase of 7.8 equivalent full power days (EFPDs) in cycle length compared with 517.4 EFPDs for the AP600 first cycle.

  15. Position Control of Linear Synchronous Motor Drives with Exploitation of Forced Dynamics Control Principles

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2004-01-01

    Full Text Available Closed-loop position control of mechanisms directly driven by linear synchronous motors with permanent magnets is presented. The control strategy is based on forced dynamic control, which is a form of feedback linearisation, yielding a non-liner multivariable control law to obtain a prescribed linear speed dynamics together with the vector control condition of mutal orthogonality between the stator current and magnetic flux vectors (assuming perfect estimates of the plant parameters. Outer position control loop is closed via simple feedback with proportional gain. Simulations of the design control sysstem, including the drive with power electronic switching, predict the intended drive performance.

  16. Evaluating Information Assurance Control Effectiveness on an Air Force Supervisory Control and Data Acquisition (SCADA) System

    Science.gov (United States)

    2011-03-01

    Byres, E. J., Lowe, J. (2004). The Myths and facts behind cyber security risks for industrial control systems . Berlin, Germany: VDE 2004 Congress...ACQUISITION (SCADA) SYSTEM THESIS Jason R. Nielsen, Major, USAF AFIT/GCO/ENG/11-10 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY AIR FORCE...DATA ACQUISITION (SCADA) SYSTEM THESIS Presented to the Faculty Department of Electrical and Computer Engineering Graduate School of

  17. Evolving intelligent vehicle control using multi-objective NEAT

    NARCIS (Netherlands)

    Willigen, W.H. van; Haasdijk, E.; Kester, L.J.H.M.

    2013-01-01

    The research in this paper is inspired by a vision of intelligent vehicles that autonomously move along motorways: they join and leave trains of vehicles (platoons), overtake other vehicles, etc. We propose a multi-objective algorithm based on NEAT and SPEA2 that evolves controllers for such

  18. Extending the enterprise through multi-level supply control

    NARCIS (Netherlands)

    Vlist, van der P.; Hoppenbrouwers, J.J.E.M.; Hegge, H.M.H.

    1997-01-01

    Demands for flexibility require larger parts of the supply chain to become customer driven. This article describes multi-level supply control (MLSC) as a mechanism to facilitate that; it allows to specify gradually and thus to shift the customer order decoupling point well across the boundary to the

  19. Predictability, Force and (Anti-)Resonance in Complex Object Control.

    Science.gov (United States)

    Maurice, Pauline; Hogan, Neville; Sternad, Dagmar

    2018-04-18

    Manipulation of complex objects as in tool use is ubiquitous and has given humans an evolutionary advantage. This study examined the strategies humans choose when manipulating an object with underactuated internal dynamics, such as a cup of coffee. The object's dynamics renders the temporal evolution complex, possibly even chaotic, and difficult to predict. A cart-and-pendulum model, loosely mimicking coffee sloshing in a cup, was implemented in a virtual environment with a haptic interface. Participants rhythmically manipulated the virtual cup containing a rolling ball; they could choose the oscillation frequency, while the amplitude was prescribed. Three hypotheses were tested: 1) humans decrease interaction forces between hand and object; 2) humans increase the predictability of the object dynamics; 3) humans exploit the resonances of the coupled object-hand system. Analysis revealed that humans chose either a high-frequency strategy with anti-phase cup-and-ball movements or a low-frequency strategy with in-phase cup-and-ball movements. Counter Hypothesis 1, they did not decrease interaction force; instead, they increased the predictability of the interaction dynamics, quantified by mutual information, supporting Hypothesis 2. To address Hypothesis 3, frequency analysis of the coupled hand-object system revealed two resonance frequencies separated by an anti-resonance frequency. The low-frequency strategy exploited one resonance, while the high-frequency strategy afforded more choice, consistent with the frequency response of the coupled system; both strategies avoided the anti-resonance. Hence, humans did not prioritize interaction force, but rather strategies that rendered interactions predictable. These findings highlight that physical interactions with complex objects pose control challenges not present in unconstrained movements.

  20. Towards Coordination and Control of Multi-robot Systems

    DEFF Research Database (Denmark)

    Quottrup, Michael Melholt

    This thesis focuses on control and coordination of mobile multi-robot systems (MRS). MRS can often deal with tasks that are difficult to be accomplished by a single robot. One of the challenges is the need to control, coordinate and synchronize the operation of several robots to perform some...... specified task. This calls for new strategies and methods which allow the desired system behavior to be specified in a formal and succinct way. Two different frameworks for the coordination and control of MRS have been investigated. Framework I - A network of robots is modeled as a network of multi...... a requirement specification in Computational Tree Logic (CTL) for a network of robots. The result is a set of motion plans for the robots which satisfy the specification. Framework II - A framework for controller synthesis for a single robot with respect to requirement specification in Linear-time Temporal...

  1. A multi-channel AC power supply controller

    International Nuclear Information System (INIS)

    Su Hong; Li Xiaogang; Ma Xiaoli; Zhou Bo; Yin Weiwei

    2003-01-01

    A multi-channel ac power supply controller developed recently by authors is introduced briefly in this paper. This controller is a computer controlled multi-electronic-switch device. This controller was developed for the automatic control and monitoring system of a 220 V ac power supply system, it is a key front-end device of the automatic control and monitoring system. There is an electronic switch in each channel, the rated load power is ≤1 kW/each channel. Another function is to sample the 220 V ac output voltage so that computer can monitor the operation state of each electronic switch. Through these switches, the 220 V ac power supply is applied to some device or apparatus that need to be powered by 220 V ac power supply. In the design, a solid-state relay was employed as an electronic switch. This controller can be connected in cascade mode. There are 8 boxes at most can be connected in cascade mode. The length of control word is 8 bit, which contains addressing information and electronic switch state setting information. The sampling output of the controller is multiplexed. It is only one bit that indicates the operating state of an electronic switch. This controller has been used in an automatic control and monitoring system for 220 V ac power supply system

  2. Effects of Carpal Tunnel Syndrome on adaptation of multi-digit forces to object mass distribution for whole-hand manipulation

    Directory of Open Access Journals (Sweden)

    Zhang Wei

    2012-11-01

    Full Text Available Abstract Background Carpal tunnel syndrome (CTS is a compression neuropathy of the median nerve that results in sensorimotor deficits in the hand. Until recently, the effects of CTS on hand function have been studied using mostly two-digit grip tasks. The purpose of this study was to investigate the coordination of multi-digit forces as a function of object center of mass (CM during whole-hand grasping. Methods Fourteen CTS patients and age- and gender-matched controls were instructed to grasp, lift, hold, and release a grip device with five digits for seven consecutive lifts while maintaining its vertical orientation. The object CM was changed by adding a mass at different locations at the base of the object. We measured forces and torques exerted by each digit and object kinematics and analyzed modulation of these variables to object CM at object lift onset and during object hold. Our task requires a modulation of digit forces at and after object lift onset to generate a compensatory moment to counteract the external moment caused by the added mass and to minimize object tilt. Results We found that CTS patients learned to generate a compensatory moment and minimized object roll to the same extent as controls. However, controls fully exploited the available degrees of freedom (DoF in coordinating their multi-digit forces to generate a compensatory moment, i.e., digit normal forces, tangential forces, and the net center of pressure on the finger side of the device at object lift onset and during object hold. In contrast, patients modulated only one of these DoFs (the net center of pressure to object CM by modulating individual normal forces at object lift onset. During object hold, however, CTS patients were able to modulate digit tangential force distribution to object CM. Conclusions Our findings suggest that, although CTS did not affect patients’ ability to perform our manipulation task, it interfered with the modulation of specific grasp

  3. Multi Car Elevator Control by using Learning Automaton

    Science.gov (United States)

    Shiraishi, Kazuaki; Hamagami, Tomoki; Hirata, Hironori

    We study an adaptive control technique for multi car elevators (MCEs) by adopting learning automatons (LAs.) The MCE is a high performance and a near-future elevator system with multi shafts and multi cars. A strong point of the system is that realizing a large carrying capacity in small shaft area. However, since the operation is too complicated, realizing an efficient MCE control is difficult for top-down approaches. For example, “bunching up together" is one of the typical phenomenon in a simple traffic environment like the MCE. Furthermore, an adapting to varying environment in configuration requirement is a serious issue in a real elevator service. In order to resolve these issues, having an autonomous behavior is required to the control system of each car in MCE system, so that the learning automaton, as the solutions for this requirement, is supposed to be appropriate for the simple traffic control. First, we assign a stochastic automaton (SA) to each car control system. Then, each SA varies its stochastic behavior distributions for adapting to environment in which its policy is evaluated with each passenger waiting times. That is LA which learns the environment autonomously. Using the LA based control technique, the MCE operation efficiency is evaluated through simulation experiments. Results show the technique enables reducing waiting times efficiently, and we confirm the system can adapt to the dynamic environment.

  4. Multi-level emulation of complex climate model responses to boundary forcing data

    Science.gov (United States)

    Tran, Giang T.; Oliver, Kevin I. C.; Holden, Philip B.; Edwards, Neil R.; Sóbester, András; Challenor, Peter

    2018-04-01

    Climate model components involve both high-dimensional input and output fields. It is desirable to efficiently generate spatio-temporal outputs of these models for applications in integrated assessment modelling or to assess the statistical relationship between such sets of inputs and outputs, for example, uncertainty analysis. However, the need for efficiency often compromises the fidelity of output through the use of low complexity models. Here, we develop a technique which combines statistical emulation with a dimensionality reduction technique to emulate a wide range of outputs from an atmospheric general circulation model, PLASIM, as functions of the boundary forcing prescribed by the ocean component of a lower complexity climate model, GENIE-1. Although accurate and detailed spatial information on atmospheric variables such as precipitation and wind speed is well beyond the capability of GENIE-1's energy-moisture balance model of the atmosphere, this study demonstrates that the output of this model is useful in predicting PLASIM's spatio-temporal fields through multi-level emulation. Meaningful information from the fast model, GENIE-1 was extracted by utilising the correlation between variables of the same type in the two models and between variables of different types in PLASIM. We present here the construction and validation of several PLASIM variable emulators and discuss their potential use in developing a hybrid model with statistical components.

  5. Multi-stage fuzzy load frequency control using PSO

    International Nuclear Information System (INIS)

    Shayeghi, H.; Jalili, A.; Shayanfar, H.A.

    2008-01-01

    In this paper, a particle swarm optimization (PSO) based multi-stage fuzzy (PSOMSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operate under deregulation based on the bilateral policy scheme. In this strategy the control is tuned on line from the knowledge base and fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by PSO algorithm, that has a strong ability to find the most optimistic results. The motivation for using the PSO technique is to reduce fuzzy system effort and take large parametric uncertainties into account. This newly developed control strategy combines the advantage of PSO and fuzzy system control techniques and leads to a flexible controller with simple stricture that is easy to implement. The proposed PSO based MSF (PSOMSF) controller is tested on a three-area restructured power system under different operating conditions and contract variations. The results of the proposed PSOMSF controller are compared with genetic algorithm based multi-stage fuzzy (GAMSF) control through some performance indices to illustrate its robust performance for a wide range of system parameters and load changes

  6. Multi-stage fuzzy load frequency control using PSO

    Energy Technology Data Exchange (ETDEWEB)

    Shayeghi, H. [Technical Engineering Department, University of Mohaghegh Ardabili, Ardabil (Iran); Jalili, A. [Islamic Azad University, Ardabil Branch, Ardabil (Iran); Shayanfar, H.A. [Center of Excellence for Power Automation and Operation, Electrical Engineering Department, Iran University of Science and Technology, Tehran (Iran)

    2008-10-15

    In this paper, a particle swarm optimization (PSO) based multi-stage fuzzy (PSOMSF) controller is proposed for solution of the load frequency control (LFC) problem in a restructured power system that operate under deregulation based on the bilateral policy scheme. In this strategy the control is tuned on line from the knowledge base and fuzzy inference, which request fewer sources and has two rule base sets. In the proposed method, for achieving the desired level of robust performance, exact tuning of membership functions is very important. Thus, to reduce the design effort and find a better fuzzy system control, membership functions are designed automatically by PSO algorithm, that has a strong ability to find the most optimistic results. The motivation for using the PSO technique is to reduce fuzzy system effort and take large parametric uncertainties into account. This newly developed control strategy combines the advantage of PSO and fuzzy system control techniques and leads to a flexible controller with simple stricture that is easy to implement. The proposed PSO based MSF (PSOMSF) controller is tested on a three-area restructured power system under different operating conditions and contract variations. The results of the proposed PSOMSF controller are compared with genetic algorithm based multi-stage fuzzy (GAMSF) control through some performance indices to illustrate its robust performance for a wide range of system parameters and load changes. (author)

  7. Reorganised force control in elbow pain patients during isometric wrist extension

    DEFF Research Database (Denmark)

    Mista, Christian Ariel; Monterde, Sonia; Inglés, Montserrat

    2018-01-01

    INTRODUCTION: Reorganised force control may be an important adaptation following painful traumas. In this study, force control adaptations were assessed in elbow pain patients. Increasing the contraction demand may overcome pain interference on the motor control and as such act as an internal...... voluntary contraction. Pressure pain thresholds were recorded at the lateral epicondyle and tibialis anterior muscle. Contraction force was recorded using a three-directional force transducer. Participants performed contractions according with visual feedback of the task-related force intensity (main...... direction of wrist extension) and another set of contractions with feedback of the three force directions. Going from the simple to the detailed force feedback will increase the demand of the motor task. Force steadiness in all 3 dimensions and force direction was extracted. RESULTS: Compared with controls...

  8. Estimation of Prestress Force Distribution in Multi-Strand System of Prestressed Concrete Structures Using Field Data Measured by Electromagnetic Sensor.

    Science.gov (United States)

    Cho, Keunhee; Cho, Jeong-Rae; Kim, Sung Tae; Park, Sung Yong; Kim, Young-Jin; Park, Young-Hwan

    2016-08-18

    The recently developed smart strand can be used to measure the prestress force in the prestressed concrete (PSC) structure from the construction stage to the in-service stage. The higher cost of the smart strand compared to the conventional strand renders it unaffordable to replace all the strands by smart strands, and results in the application of only a limited number of smart strands in the PSC structure. However, the prestress forces developed in the strands of the multi-strand system frequently adopted in PSC structures differ from each other, which means that the prestress force in the multi-strand system cannot be obtained by simple proportional scaling using the measurement of the smart strand. Therefore, this study examines the prestress force distribution in the multi-strand system to find the correlation between the prestress force measured by the smart strand and the prestress force distribution in the multi-strand system. To that goal, the prestress force distribution was measured using electromagnetic sensors for various factors of the multi-strand system adopted on site in the fabrication of actual PSC girders. The results verified the possibility to assume normal distribution for the prestress force distribution per anchor head, and a method computing the mean and standard deviation defining the normal distribution is proposed. This paper presents a meaningful finding by proposing an estimation method of the prestress force based upon field-measured data of the prestress force distribution in the multi-strand system of actual PSC structures.

  9. Multi-Level Wild Land Fire Fighting Management Support System for an Optimized Guidance of Ground and Air Forces

    Science.gov (United States)

    Almer, Alexander; Schnabel, Thomas; Perko, Roland; Raggam, Johann; Köfler, Armin; Feischl, Richard

    2016-04-01

    Climate change will lead to a dramatic increase in damage from forest fires in Europe by the end of this century. In the Mediterranean region, the average annual area affected by forest fires has quadrupled since the 1960s (WWF, 2012). The number of forest fires is also on the increase in Central and Northern Europe. The Austrian forest fire database shows a total of 584 fires for the period 2012 to 2014, while even large areas of Sweden were hit by forest fires in August 2014, which were brought under control only after two weeks of intense fire-fighting efforts supported by European civil protection modules. Based on these facts, the improvements in forest fire control are a major international issue in the quest to protect human lives and resources as well as to reduce the negative environmental impact of these fires to a minimum. Within this paper the development of a multi-functional airborne management support system within the frame of the Austrian national safety and security research programme (KIRAS) is described. The main goal of the developments is to assist crisis management tasks of civil emergency teams and armed forces in disaster management by providing multi spectral, near real-time airborne image data products. As time, flexibility and reliability as well as objective information are crucial aspects in emergency management, the used components are tailored to meet these requirements. An airborne multi-functional management support system was developed as part of the national funded project AIRWATCH, which enables real-time monitoring of natural disasters based on optical and thermal images. Airborne image acquisition, a broadband line of sight downlink and near real-time processing solutions allow the generation of an up-to-date geo-referenced situation map. Furthermore, this paper presents ongoing developments for innovative extensions and research activities designed to optimize command operations in national and international fire

  10. Real-time tracking control of electro-hydraulic force servo systems using offline feedback control and adaptive control.

    Science.gov (United States)

    Shen, Gang; Zhu, Zhencai; Zhao, Jinsong; Zhu, Weidong; Tang, Yu; Li, Xiang

    2017-03-01

    This paper focuses on an application of an electro-hydraulic force tracking controller combined with an offline designed feedback controller (ODFC) and an online adaptive compensator in order to improve force tracking performance of an electro-hydraulic force servo system (EHFS). A proportional-integral controller has been employed and a parameter-based force closed-loop transfer function of the EHFS is identified by a continuous system identification algorithm. By taking the identified system model as a nominal plant model, an H ∞ offline design method is employed to establish an optimized feedback controller with consideration of the performance, control efforts, and robustness of the EHFS. In order to overcome the disadvantage of the offline designed controller and cope with the varying dynamics of the EHFS, an online adaptive compensator with a normalized least-mean-square algorithm is cascaded to the force closed-loop system of the EHFS compensated by the ODFC. Some comparative experiments are carried out on a real-time EHFS using an xPC rapid prototype technology, and the proposed controller yields a better force tracking performance improvement. Copyright © 2016. Published by Elsevier Ltd.

  11. Control of forced vibrations of mechanical structures by an electromagnetic controller with a permanent magnet

    DEFF Research Database (Denmark)

    Stein, George Juraj; Darula, Radoslav; Sorokin, Sergey

    2012-01-01

    A theoretical analysis of an electromagnetic vibration controller is presented. The analyzed device consists of a pot-type iron core with a coil and a permanent magnet as a source of constant magnetic flux. The magnetic circuit is closed by a yoke, excited by an external harmonic mechanical force....... The so generated magnetic flux variation induces alternating voltage in the electric circuit, which is dissipated in a shunt resistor. The induced current driven through the coil generates magnetic force, which damps the excitation force and changes the damped natural frequency of the oscillatory system....... Due to the hysteretic effects in the magnetic material the internal losses influence the overall system’s performance. A mathematical model of the force balance in the oscillatory system is derived in a simplified, linearised form. The electric as well as mechanical system is modelled using lumped...

  12. The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

    Science.gov (United States)

    Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

    2017-05-01

    Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

  13. Attitude and Configuration Control of Flexible Multi-Body Spacecraft

    Science.gov (United States)

    Cho, Sung-Ki; Cochran, John E., Jr.

    2002-06-01

    Multi-body spacecraft attitude and configuration control formulations based on the use of collaborative control theory are considered. The control formulations are based on two-player, nonzero-sum, differential game theory applied using a Nash strategy. It is desired that the control laws allow different components of the multi-body system to perform different tasks. For example, it may be desired that one body points toward a fixed star while another body in the system slews to track another satellite. Although similar to the linear quadratic regulator formulation, the collaborative control formulation contains a number of additional design parameters because the problem is formulated as two control problems coupled together. The use of the freedom of the partitioning of the total problem into two coupled control problems and the selection of the elements of the cross-coupling matrices are specific problems addressed in this paper. Examples are used to show that significant improvement in performance, as measured by realistic criteria, of collaborative control over conventional linear quadratic regulator control can be achieved by using proposed design guidelines.

  14. Attitude and Configuration Control of Flexible Multi-Body Spacecraft

    Directory of Open Access Journals (Sweden)

    Sungki Cho

    2002-06-01

    Full Text Available Multi-body spacecraft attitude and configuration control formulations based on the use of collaborative control theory are considered. The control formulations are based on two-player, nonzero-sum, differential game theory applied using a Nash strategy. It is desired that the control laws allow different components of the multi-body system to perform different tasks. For example, it may be desired that one body points toward a fixed star while another body in the system slews to track another satellite. Although similar to the linear quadratic regulator formulation, the collaborative control formulation contains a number of additional design parameters because the problem is formulated as two control problems coupled together. The use of the freedom of the partitioning of the total problem into two coupled control problems and the selection of the elements of the cross-coupling matrices are specific problems addressed in this paper. Examples are used to show that significant improvement in performance, as measured by realistic criteria, of collaborative control over conventional linear quadratic regulator control can be achieved by using proposed design guidelines.

  15. An Artificial Neural Network Modeling for Force Control System of a Robotic Pruning Machine

    Directory of Open Access Journals (Sweden)

    Ali Hashemi

    2014-06-01

    Full Text Available Nowadays, there has been an increasing application of pruning robots for planted forests due to the growing concern on the efficiency and safety issues. Power consumption and working time of agricultural machines have become important issues due to the high value of energy in modern world. In this study, different multi-layer back-propagation networks were utilized for mapping the complex and highly interactive of pruning process parameters and to predict power consumption and cutting time of a force control equipped robotic pruning machine by knowing input parameters such as: rotation speed, stalk diameter, and sensitivity coefficient. Results showed significant effects of all input parameters on output parameters except rotational speed on cutting time. Therefore, for reducing the wear of cutting system, a less rotational speed in every sensitivity coefficient should be selected.

  16. Heavy-tailed distribution of the SSH Brute-force attack duration in a multi-user environment

    Science.gov (United States)

    Lee, Jae-Kook; Kim, Sung-Jun; Park, Chan Yeol; Hong, Taeyoung; Chae, Huiseung

    2016-07-01

    Quite a number of cyber-attacks to be place against supercomputers that provide highperformance computing (HPC) services to public researcher. Particularly, although the secure shell protocol (SSH) brute-force attack is one of the traditional attack methods, it is still being used. Because stealth attacks that feign regular access may occur, they are even harder to detect. In this paper, we introduce methods to detect SSH brute-force attacks by analyzing the server's unsuccessful access logs and the firewall's drop events in a multi-user environment. Then, we analyze the durations of the SSH brute-force attacks that are detected by applying these methods. The results of an analysis of about 10 thousands attack source IP addresses show that the behaviors of abnormal users using SSH brute-force attacks are based on human dynamic characteristics of a typical heavy-tailed distribution.

  17. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    International Nuclear Information System (INIS)

    Morawski, Ireneusz; Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert

    2015-01-01

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations

  18. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, Ireneusz [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany); Institute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław (Poland); Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2015-12-15

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.

  19. Development of a Carbon Nanotube-Based Touchscreen Capable of Multi-Touch and Multi-Force Sensing

    OpenAIRE

    Kim, Wonhyo; Oh, Haekwan; Kwak, Yeonhwa; Park, Kwangbum; Ju, Byeong-Kwon; Kim, Kunnyun

    2015-01-01

    A force sensing touchscreen, which detects touch point and touch force simultaneously by sensing a change in electric capacitance, was designed and fabricated. It was made with single-walled carbon nanotubes (SWCNTs) which have better mechanical and chemical characteristics than the indium-tin-oxide transparent electrodes used in most contemporary touchscreen devices. The SWCNTs, with a transmittance of about 85% and electric conductivity of 400 Ω per square; were coated and patterned on glas...

  20. Aligning Forces for Quality multi-stakeholder healthcare alliances: do they have a sustainable future?

    Science.gov (United States)

    Alexander, Jeffrey A; Hearld, Larry R; Wolf, Laura J; Vanderbrink, Jocelyn M

    2016-08-01

    Multi-stakeholder healthcare alliances in the Robert Wood Johnson Foundation's Aligning Forces for Quality (AF4Q) program brought together diverse stakeholders to work collaboratively to improve healthcare in their local communities. This article evaluates how well the AF4Q alliances were collectively positioned to sustain themselves as AF4Q program support ended. This analysis relied on a mixed-methods design using data from a survey of more than 700 participants in 15 of the 16 AF4Q alliances (1 alliance was unable to participate because it was in the process of closing down operations at the time of survey implementation), qualitative interviews with leaders in all 16 of the alliances, and secondary sources. Qualitative analysis of interview data and secondary sources were used to develop a classification of alliance strategic directions after the AF4Q program relative to their strategies during the AF4Q initiative. Descriptive analyses of survey data were conducted in the following areas: (1) alliance priorities for sustainability, (2) alliance positioning for sustainability, and (3) alliance challenges to sustainability. The likelihood of sustainability and the strategic direction of the former AF4Q alliances are both decidedly mixed. A substantial number of alliances are at risk because of an unclear strategic direction following the AF4Q program, poor financial support, and a lack of relevant community leadership. Some have a clear plan to continue on the path they set during the program. Others appear likely to continue to operate, but they plan to do so in a form that differs from the neutral convener multi-stakeholder model emphasized during the AF4Q program as they specialize, make a major shift in focus, develop fee-for-service products, or focus on particular stakeholder groups (ie, employers and providers). In most cases, preserving the organization itself, rather than its programmatic activities from the AF4Q program era, appeared to receive the

  1. Anisotropic spin motive force in multi-layered Dirac fermion system, α-(BEDT-TTF)2I3

    International Nuclear Information System (INIS)

    Kubo, K; Morinari, T

    2015-01-01

    We investigate the anisotropic spin motive force in α-(BEDT-TTF) 2 I 3 , which is a multi-layered massless Dirac fermion system under pressure. Assuming the interlayer antiferromagnetic interaction and the interlayer anisotropic ferromagnetic interaction, we numerically examine the spin ordered state of the ground state using the steepest descent method. The anisotropic interaction leads to the anisotropic spin ordered state. We calculate the spin motive force produced by the anisotropic spin texture. The result quantitatively agrees with the experiment. (paper)

  2. Greenridge Multi-Pollutant Control Project Preliminary Public Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Connell, Daniel P

    2009-01-12

    The Greenidge Multi-Pollutant Control Project is being conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electrical generating units (EGUs). The multi-pollutant control system includes a hybrid selective non-catalytic reduction (SNCR)/in-duct selective catalytic reduction (SCR) system to reduce NOx emissions by {ge}60%, followed by a Turbosorp{reg_sign} circulating fluidized bed dry scrubber system to reduce emissions of SO{sub 2}, SO{sub 3}, HCl, and HF by {ge}95%. Mercury removal of {ge}90% is also targeted via the co-benefits afforded by the in-duct SCR, dry scrubber, and baghouse and by injection of activated carbon upstream of the scrubber, as required. The technology is particularly well suited, because of its relatively low capital and maintenance costs and small space requirements, to meet the needs of coal-fired units with capacities of 50-300 MWe. There are about 440 such units in the United States that currently are not equipped with SCR, flue gas desulfurization (FGD), or mercury control systems. These smaller units are a valuable part of the nation's energy infrastructure, constituting about 60 GW of installed capacity. However, with the onset of the Clean Air Interstate Rule, Clean Air Mercury Rule, and various state environmental actions requiring deep reductions in emissions of SO{sub 2}, NO{sub x}, and mercury, the continued operation of these units increasingly depends upon the ability to identify viable air pollution control retrofit options for them. The large capital costs and sizable space requirements associated with conventional technologies such as SCR and wet FGD make these technologies unattractive for many smaller units. The Greenidge Project aims to confirm

  3. Operational Command and Control: Lessons for Today's Joint Force from Grenada, Somalia, and Kosovo

    National Research Council Canada - National Science Library

    Foraker III, Joseph C

    2007-01-01

    This paper examines operational command and control issues encountered during Operation Urgent Fury in Grenada, the deployment of Task Force Ranger in Mogadishu, Somalia, and Operation Allied Force in Kosovo...

  4. Multi drop bus controller for IBM PC/AT

    International Nuclear Information System (INIS)

    Bardik, Yu.I.; Kalistratov, E.N.; Matyushin, A.A.; Obukhov, G.A.; Trofimov, N.N.

    1993-01-01

    The module PC-AT-PBC gives a possibility to create a working place based on the computer IBM PC/AT for testing of hardware which is compatible with the multi drop bus. The KP1830BE31 micro program change turns the module into timing generator for power supply controllers of the UNK correction system. The structure of the module, functional parts, library functions and two application programs have been described. 4 refs., 9 figs

  5. Force Control for a Pneumatic Cylinder Using Generalized Predictive Controller Approach

    Directory of Open Access Journals (Sweden)

    Ahmad ’Athif Mohd Faudzi

    2014-01-01

    Full Text Available Pneumatic cylinder is a well-known device because of its high power to weight ratio, easy use, and environmental safety. Pneumatic cylinder uses air as its power source and converts it to a possible movement such as linear and rotary movement. In order to control the pneumatic cylinder, controller algorithm is needed to control the on-off solenoid valve with encoder and pressure sensor as the feedback inputs. In this paper, generalized predictive controller (GPC is proposed as the control strategy for the pneumatic cylinder force control. To validate and compare the performance, proportional-integral (PI controller is also presented. Both controllers algorithms GPC and PI are developed using existing linear model of the cylinder from previous research. Results are presented in simulation and experimental approach using MATLAB-Simulink as the platform. The results show that the GPC is capable of fast response with low steady state error and percentage overshoot compared to PI.

  6. Controlling the dynamics of multi-state neural networks

    International Nuclear Information System (INIS)

    Jin, Tao; Zhao, Hong

    2008-01-01

    In this paper, we first analyze the distribution of local fields (DLF) which is induced by the memory patterns in the Q-Ising model. It is found that the structure of the DLF is closely correlated with the network dynamics and the system performance. However, the design rule adopted in the Q-Ising model, like the other rules adopted for multi-state neural networks with associative memories, cannot be applied to directly control the DLF for a given set of memory patterns, and thus cannot be applied to further study the relationships between the structure of the DLF and the dynamics of the network. We then extend a design rule, which was presented recently for designing binary-state neural networks, to make it suitable for designing general multi-state neural networks. This rule is able to control the structure of the DLF as expected. We show that controlling the DLF not only can affect the dynamic behaviors of the multi-state neural networks for a given set of memory patterns, but also can improve the storage capacity. With the change of the DLF, the network shows very rich dynamic behaviors, such as the 'chaos phase', the 'memory phase', and the 'mixture phase'. These dynamic behaviors are also observed in the binary-state neural networks; therefore, our results imply that they may be the universal behaviors of feedback neural networks

  7. Development of a Carbon Nanotube-Based Touchscreen Capable of Multi-Touch and Multi-Force Sensing.

    Science.gov (United States)

    Kim, Wonhyo; Oh, Haekwan; Kwak, Yeonhwa; Park, Kwangbum; Ju, Byeong-Kwon; Kim, Kunnyun

    2015-11-13

    A force sensing touchscreen, which detects touch point and touch force simultaneously by sensing a change in electric capacitance, was designed and fabricated. It was made with single-walled carbon nanotubes (SWCNTs) which have better mechanical and chemical characteristics than the indium-tin-oxide transparent electrodes used in most contemporary touchscreen devices. The SWCNTs, with a transmittance of about 85% and electric conductivity of 400 Ω per square; were coated and patterned on glass and polyethyleneterephthalate (PET) film substrates. The constructed force sensing touchscreen has a total size and thickness of 62 mm × 100 mm × 1.4 mm, and is composed of 11 driving line and 19 receiving line channels. The gap between the channels was designed to be 20 µm, taking visibility into consideration, and patterned by a photolithography and plasma etching processes. The mutual capacitance formed by the upper and lower transparent electrodes was initially about 2.8 pF and, on applying a 500 gf force with a 3 mm diameter tip, it showed a 25% capacitance variation. Furthermore, the touchscreen can detect multiple touches and forces simultaneously and is unaffected by touch material characteristics, such as conductance or non-conductance.

  8. Development of a Carbon Nanotube-Based Touchscreen Capable of Multi-Touch and Multi-Force Sensing

    Directory of Open Access Journals (Sweden)

    Wonhyo Kim

    2015-11-01

    Full Text Available A force sensing touchscreen, which detects touch point and touch force simultaneously by sensing a change in electric capacitance, was designed and fabricated. It was made with single-walled carbon nanotubes (SWCNTs which have better mechanical and chemical characteristics than the indium-tin-oxide transparent electrodes used in most contemporary touchscreen devices. The SWCNTs, with a transmittance of about 85% and electric conductivity of 400 Ω per square; were coated and patterned on glass and polyethyleneterephthalate (PET film substrates. The constructed force sensing touchscreen has a total size and thickness of 62 mm × 100 mm × 1.4 mm, and is composed of 11 driving line and 19 receiving line channels. The gap between the channels was designed to be 20 µm, taking visibility into consideration, and patterned by a photolithography and plasma etching processes. The mutual capacitance formed by the upper and lower transparent electrodes was initially about 2.8 pF and, on applying a 500 gf force with a 3 mm diameter tip, it showed a 25% capacitance variation. Furthermore, the touchscreen can detect multiple touches and forces simultaneously and is unaffected by touch material characteristics, such as conductance or non-conductance.

  9. Micro-vision servo control of a multi-axis alignment system for optical fiber assembly

    International Nuclear Information System (INIS)

    Chen, Weihai; Yu, Fei; Qu, Jianliang; Chen, Wenjie; Zhang, Jianbin

    2017-01-01

    This paper describes a novel optical fiber assembly system featuring a multi-axis alignment function based on micro-vision feedback control. It consists of an active parallel alignment mechanism, a passive compensation mechanism, a micro-gripper and a micro-vision servo control system. The active parallel alignment part is a parallelogram-based design with remote-center-of-motion (RCM) function to achieve precise rotation without fatal lateral motion. The passive mechanism, with five degrees of freedom (5-DOF), is used to implement passive compensation for multi-axis errors. A specially designed 1-DOF micro-gripper mounted onto the active parallel alignment platform is adopted to grasp and rotate the optical fiber. A micro-vision system equipped with two charge-coupled device (CCD) cameras is introduced to observe the small field of view and obtain multi-axis errors for servo feedback control. The two CCD cameras are installed in an orthogonal arrangement—thus the errors can be easily measured via the captured images. Meanwhile, a series of tracking and measurement algorithms based on specific features of the target objects are developed. Details of the force and displacement sensor information acquisition in the assembly experiment are also provided. An experiment demonstrates the validity of the proposed visual algorithm by achieving the task of eliminating errors and inserting an optical fiber to the U-groove accurately. (paper)

  10. Multi-Stage Flotation for the Removal of Ash from Fine Graphite Using Mechanical and Centrifugal Forces

    OpenAIRE

    Xiangning Bu; Tuantuan Zhang; Yaoli Peng; Guangyuan Xie; Erdong Wu

    2018-01-01

    Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote its grade and economic value. In rougher flotation, both the mechanical flotation cell and flotation column reduced the ash content of the graphite ore from 15.43% to 10.8%, while the ...

  11. Environmental Assessment for the Construction of a Three-Bay Multi-Aircraft Hangar Tinker Air Force Base, Oklahoma

    Science.gov (United States)

    2008-01-01

    Years 2005 through 2009: VOCE = .016 * Trips NOxE = .015 * Trips PM10E = .0022 * Trips COE = .262 * Trips Appendix A: Air Quality January 2008...Final EA for the Construction of a Three-Bay Multi-Aircraft Hangar Page A-9 Tinker Air Force Base, Oklahoma Years 2010 and beyond: VOCE = .012...Trips NOxE = .013 * Trips PM10E = .0022 * Trips COE = .262 * Trips To convert from pounds per day to tons per year: VOC (tons/year) = VOCE

  12. Multi-model Simulation for Optimal Control of Aeroacoustics.

    Energy Technology Data Exchange (ETDEWEB)

    Collis, Samuel Scott; Chen, Guoquan

    2005-05-01

    Flow-generated noise, especially rotorcraft noise has been a serious concern for bothcommercial and military applications. A particular important noise source for rotor-craft is Blade-Vortex-Interaction (BVI)noise, a high amplitude, impulsive sound thatoften dominates other rotorcraft noise sources. Usually BVI noise is caused by theunsteady flow changes around various rotor blades due to interactions with vorticespreviously shed by the blades. A promising approach for reducing the BVI noise isto use on-blade controls, such as suction/blowing, micro-flaps/jets, and smart struc-tures. Because the design and implementation of such experiments to evaluate suchsystems are very expensive, efficient computational tools coupled with optimal con-trol systems are required to explore the relevant physics and evaluate the feasibilityof using various micro-fluidic devices before committing to hardware.In this thesis the research is to formulate and implement efficient computationaltools for the development and study of optimal control and design strategies for com-plex flow and acoustic systems with emphasis on rotorcraft applications, especiallyBVI noise control problem. The main purpose of aeroacoustic computations is todetermine the sound intensity and directivity far away from the noise source. How-ever, the computational cost of using a high-fidelity flow-physics model across thefull domain is usually prohibitive and itmight also be less accurate because of thenumerical diffusion and other problems. Taking advantage of the multi-physics andmulti-scale structure of this aeroacoustic problem, we develop a multi-model, multi-domain (near-field/far-field) method based on a discontinuous Galerkin discretiza-tion. In this approach the coupling of multi-domains and multi-models is achievedby weakly enforcing continuity of normal fluxes across a coupling surface. For ourinterested aeroacoustics control problem, the adjoint equations that determine thesensitivity of the cost

  13. MIDA - Optimizing control room performance through multi-modal design

    International Nuclear Information System (INIS)

    Ronan, A. M.

    2006-01-01

    Multi-modal interfaces can support the integration of humans with information processing systems and computational devices to maximize the unique qualities that comprise a complex system. In a dynamic environment, such as a nuclear power plant control room, multi-modal interfaces, if designed correctly, can provide complementary interaction between the human operator and the system which can improve overall performance while reducing human error. Developing such interfaces can be difficult for a designer without explicit knowledge of Human Factors Engineering principles. The Multi-modal Interface Design Advisor (MIDA) was developed as a support tool for system designers and developers. It provides design recommendations based upon a combination of Human Factors principles, a knowledge base of historical research, and current interface technologies. MIDA's primary objective is to optimize available multi-modal technologies within a human computer interface in order to balance operator workload with efficient operator performance. The purpose of this paper is to demonstrate MIDA and illustrate its value as a design evaluation tool within the nuclear power industry. (authors)

  14. A Novel Secondary Control for Microgrid Based on Synergetic Control of Multi-Agent System

    Directory of Open Access Journals (Sweden)

    Zhiwen Yu

    2016-03-01

    Full Text Available In power systems, the secondary control is a very useful way to restore the system frequency and voltage to the rated value. This paper tries to propose a secondary frequency and voltage control of islanded microgrids based on the distributed synergetic control of multi-agent systems. In the proposed control, since each distributed generation only requires its own information and that of the neighbors, the secondary control is fully distributed. The system is more reliable because the central controller and complex communication network are reduced in the distributed structure. Based on multi-agent systems, the dynamic model is established, and distributed synergetic control algorithms are given to design the secondary control of the islanded microgrid. Meanwhile, the system has globally asymptotic stability under the proposed control, which is proved by the direct Lyapunov method. Simulation results about a test microgrid are given to verify the effectiveness of the proposed control.

  15. Interaction Control Protocols for Distributed Multi-user Multi-camera Environments

    Directory of Open Access Journals (Sweden)

    Gareth W Daniel

    2003-10-01

    Full Text Available Video-centred communication (e.g., video conferencing, multimedia online learning, traffic monitoring, and surveillance is becoming a customary activity in our lives. The management of interactions in such an environment is a complicated HCI issue. In this paper, we present our study on a collection of interaction control protocols for distributed multiuser multi-camera environments. These protocols facilitate different approaches to managing a user's entitlement for controlling a particular camera. We describe a web-based system that allows multiple users to manipulate multiple cameras in varying remote locations. The system was developed using the Java framework, and all protocols discussed have been incorporated into the system. Experiments were designed and conducted to evaluate the effectiveness of these protocols, and to enable the identification of various human factors in a distributed multi-user and multi-camera environment. This work provides an insight into the complexity associated with the interaction management in video-centred communication. It can also serve as a conceptual and experimental framework for further research in this area.

  16. Stop Blaming Disasters on Forces Beyond Our Control

    Energy Technology Data Exchange (ETDEWEB)

    Matalucci, R.V.

    1999-04-09

    As we enter the new millennium, let us recognize that the losses resulting from natural or malevolent events that cause major property damage, severe injuries, and unnecessary death are not always due to forces beyond our control. We can prevent these losses by changing the way we think and act about design and construction projects. New tools, technologies, and techniques can improve structural safety, security, and reliability and protect owners, occupants, and users against loss and casualties. Hurricane Mitch, the African embassy bombings, the ice storms in Canada and the northeastern US last winter, the Oklahoma City bombing, flooding and earthquakes in California, tornadoes and flooding in Florida, and wildfires in the Southwest are threats to the safety and security of the public and the reliability of our constructed environment. Today's engineering design community must recognize these threats and address them in our standards, building codes, and designs. We know that disasters will continue to strike and we must reduce their impact on the public. We must demand and create innovative solutions that assure a higher level of structural performance when disasters strike.

  17. Advanced Controls for the Multi-pod Centipod WEC device

    Energy Technology Data Exchange (ETDEWEB)

    McCall, Alan [Dehlsen Associates, LLC, Santa Barabara, CA (United States); Fleming, Alex [Dehlsen Associates, LLC, Santa Barabara, CA (United States)

    2016-02-15

    Dehlsen Associates, LLC (DA) has developed a Wave Energy Converter (WEC), Centipod, which is a multiple point absorber, extracting wave energy primarily in the heave direction through a plurality of point absorber floats sharing a common stable reference structure. The objective of this project was to develop advanced control algorithms that will be used to reduce Levelized Cost of Energy (LCOE). This project investigated the use of Model Predictive Control (MPC) to improve the power capture of the WEC. The MPC controller developed in this work is a state-space, “look ahead” controller approach using knowledge of past and current states to predict future states to take action with the PTO to maximize power capture while still respecting system constraints. In order to maximize power, which is the product of force and velocity, the controller must aim to create phase alignment between excitation force and velocity. This project showed a 161% improvement in the Annual Energy Production (AEP) for the Centipod WEC when utilizing MPC, compared to a baseline, fixed passive damping control strategy. This improvement in AEP was shown to provide a substantial benefit to the WEC’s overall Cost of Energy, reducing LCOE by 50% from baseline. The results of this work proved great potential for the adoption of Model Predictive Controls in Wave Energy Converters.

  18. The force control and path planning of electromagnetic induction-based massage robot.

    Science.gov (United States)

    Wang, Wendong; Zhang, Lei; Li, Jinzhe; Yuan, Xiaoqing; Shi, Yikai; Jiang, Qinqin; He, Lijing

    2017-07-20

    Massage robot is considered as an effective physiological treatment to relieve fatigue, improve blood circulation, relax muscle tone, etc. The simple massage equipment quickly spread into market due to low cost, but they are not widely accepted due to restricted massage function. Complicated structure and high cost caused difficulties for developing multi-function massage equipment. This paper presents a novel massage robot which can achieve tapping, rolling, kneading and other massage operations, and proposes an improved reciprocating path planning algorithm to improve massage effect. The number of coil turns, the coil current and the distance between massage head and yoke were chosen to investigate the influence on massage force by finite element method. The control system model of the wheeled massage robot was established, including control subsystem of the motor, path algorithm control subsystem, parameter module of the massage robot and virtual reality interface module. The improved reciprocating path planning algorithm was proposed to improve regional coverage rate and massage effect. The influence caused by coil current, the number of coil turns and the distance between massage head and yoke were simulated in Maxwell. It indicated that coil current has more important influence compared to the other two factors. The path planning simulation of the massage robot was completed in Matlab, and the results show that the improved reciprocating path planning algorithm achieved higher coverage rate than the traditional algorithm. With the analysis of simulation results, it can be concluded that the number of coil turns and the distance between the moving iron core and the yoke could be determined prior to coil current, and the force can be controllable by optimizing structure parameters of massage head and adjusting coil current. Meanwhile, it demonstrates that the proposed algorithm could effectively improve path coverage rate during massage operations, therefore

  19. Hybrid Force and Position Control Strategy of Robonaut Performing Object Transfer Task

    Directory of Open Access Journals (Sweden)

    Chen Gang

    2018-01-01

    Full Text Available This paper proposes a coordinated hybrid force/position control strategy of robonaut performing object transfer operation. Firstly, the constraint relationships between robonaut and object are presented. Base on them, the unified dynamic model of the robonaut and object is established to design the hybrid force/position control method. The movement, the internal force and the external constraint force of the object are considered as the control targets of the control system. Finally, a MATLAB simulation of the robonaut performing object transfer task verifies the correctness and effectiveness of the proposed method. The results show that all the targets can be control accurately by using the method proposed in this paper. The presented control method can control both internal and external forces while maintaining control accuracy, which is a common control strategy.

  20. Control of thumb force using surface functional electrical stimulation and muscle load sharing

    Science.gov (United States)

    2013-01-01

    Background Stroke survivors often have difficulties in manipulating objects with their affected hand. Thumb control plays an important role in object manipulation. Surface functional electrical stimulation (FES) can assist movement. We aim to control the 2D thumb force by predicting the sum of individual muscle forces, described by a sigmoidal muscle recruitment curve and a single force direction. Methods Five able bodied subjects and five stroke subjects were strapped in a custom built setup. The forces perpendicular to the thumb in response to FES applied to three thumb muscles were measured. We evaluated the feasibility of using recruitment curve based force vector maps in predicting output forces. In addition, we developed a closed loop force controller. Load sharing between the three muscles was used to solve the redundancy problem having three actuators to control forces in two dimensions. The thumb force was controlled towards target forces of 0.5 N and 1.0 N in multiple directions within the individual’s thumb work space. Hereby, the possibilities to use these force vector maps and the load sharing approach in feed forward and feedback force control were explored. Results The force vector prediction of the obtained model had small RMS errors with respect to the actual measured force vectors (0.22±0.17 N for the healthy subjects; 0.17±0.13 N for the stroke subjects). The stroke subjects showed a limited work range due to limited force production of the individual muscles. Performance of feed forward control without feedback, was better in healthy subjects than in stroke subjects. However, when feedback control was added performances were similar between the two groups. Feedback force control lead, especially for the stroke subjects, to a reduction in stationary errors, which improved performance. Conclusions Thumb muscle responses to FES can be described by a single force direction and a sigmoidal recruitment curve. Force in desired direction can be

  1. Multi-objective optimization of surface roughness, cutting forces, productivity and Power consumption when turning of Inconel 718

    Directory of Open Access Journals (Sweden)

    Hamid Tebassi

    2016-01-01

    Full Text Available Nickel based super alloys are excellent for several applications and mainly in structural components submitted to high temperatures owing to their high strength to weight ratio, good corrosion resistance and metallurgical stability such as in cases of jet engine and gas turbine components. The current work presents the experimental investigations of the cutting parameters effects (cutting speed, depth of cut and feed rate on the surface roughness, cutting force components, productivity and power consumption during dry conditions in straight turning using coated carbide tool. The mathematical models for output parameters have been developed using Box-Behnken design with 15 runs and Box-Cox transformation was used for improving normality. The results of the analysis have shown that the surface finish was statistically sensitive to the feed rate and cutting speed with the contribution of 43.58% and 23.85% respectively, while depth of cut had the greatest effect on the evolution of cutting force components with the contribution of 79.87% for feed force, 66.92% for radial force and 66.26% for tangential force. Multi-objective optimization procedure allowed minimizing roughness Ra, cutting forces and power consumption and maximizing material removal rate using desirability approach.

  2. Miniature large range multi-axis force-torque sensor for biomechanical applications

    International Nuclear Information System (INIS)

    Brookhuis, R A; Sanders, R G P; Ma, K; Lammerink, T S J; De Boer, M J; Krijnen, G J M; Wiegerink, R J

    2015-01-01

    A miniature force sensor for the measurement of forces and moments at a human fingertip is designed and realized. Thin silicon pillars inside the sensor provide in-plane guidance for shear force measurement and provide the spring constant in normal direction. A corrugated silicon ring around the force sensitive area provides the spring constant in shear direction and seals the interior of the sensor. To detect all load components, capacitive read-out is used. A novel electrode pattern results in a large shear force sensitivity. The fingertip force sensor has a wide force range of up to 60 N in normal direction, ± 30 N in shear direction and a torque range of ± 25 N mm. (paper)

  3. Model and control of the isolated multi-modular converter

    DEFF Research Database (Denmark)

    Verdugo, Cristian; Candela, Jose Ignacio; Blaabjerg, Frede

    2017-01-01

    Multi-modular converters have proven to be one of the most suitable topology to be used in high and power applications. The modularity of these configurations offer several advantages, such as: high quality voltage, redundancy and high efficiency. In these converters, the series connection...... voltages. However, increasing the number of conversion stages, increase also the losses and the implementation costs. In order to overcome these drawbacks, a new configuration of multi-modular converter is proposed in this paper. The proposed converter provides isolation with one conversion stage by means...... of using low frequency transformers in each module. The main principle behind this concept, the control structure and simulation results are presented to validate the proposed configuration....

  4. PLC-Based Pressure Control in Multi-Pump Applications

    Directory of Open Access Journals (Sweden)

    Vodovozov Valery

    2015-12-01

    Full Text Available The paper is devoted to the centrifugal pumps represented the most popular type of pumping equipment used in different areas. The pressure control approach for variable speed driven (VSD parallel connected centrifugal pumps is reported. The goal of the study is optimization of some quality indices, such as efficiency, consumed power, productivity, energy carrier temperature, heat irradiation, etc. One of them – efficiency – has been studied in the paper more carefully. The mathematical model of pumping process is discussed and a vector-matrix description of the multi-pump application is given. The program-based pressure control system is developed which productivity is changed by regulating the number of working pumps. The paper introduces new pressure control algorithms based on the working point estimation intended for programmable logical controllers (PLC. Experiments prove correctness of the offered methodology.

  5. Demand controlled ventilation for multi-family dwellings

    DEFF Research Database (Denmark)

    Mortensen, Dorthe Kragsig

    for centrally balanced DCV systems with heat recovery. A design expected to fulfill this requirement was investigated in detail with regard to its electricity consumption by evaluating a control strategy that resets the static pressure set point at part load. The results showed that this control strategy can......The present thesis “Demand controlled ventilation for multi-family dwellings” constitutes the summary of a three year project period during which demand specification and system design of demand controlled ventilation for residential buildings were studied. Most standards and buildings codes...... can be reduced compared to a system with constant air flow. A literature study on indoor pollutants in homes, their sources and their impact on humans formed the basis for the demand specification. Emission of pollutants in residential buildings roughly fall into constantly emitted background sources...

  6. Towards Automatic Controller Design using Multi-Objective Evolutionary Algorithms

    DEFF Research Database (Denmark)

    Pedersen, Gerulf

    of evolutionary computation, a choice was made to use multi-objective algorithms for the purpose of aiding in automatic controller design. More specifically, the choice was made to use the Non-dominated Sorting Genetic Algorithm II (NSGAII), which is one of the most potent algorithms currently in use...... for automatic controller design. However, because the field of evolutionary computation is relatively unknown in the field of control engineering, this thesis also includes a comprehensive introduction to the basic field of evolutionary computation as well as a description of how the field has previously been......In order to design the controllers of tomorrow, a need has risen for tools that can aid in the design of these. A desire to use evolutionary computation as a tool to achieve that goal is what gave inspiration for the work contained in this thesis. After having studied the foundations...

  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. Modelling and Control of the Multi-Stage Cable Pulley-Driven Flexible-Joint Robot

    Directory of Open Access Journals (Sweden)

    Phongsaen Pitakwatchara

    2014-07-01

    Full Text Available This work is concerned with the task space impedance control of a robot driven through a multi-stage nonlinear flexible transmission system. Specifically, a two degrees-of-freedom cable pulley-driven flexible-joint robot is considered. Realistic modelling of the system is developed within the bond graph modelling framework. The model captures the nonlinear compliance behaviour of the multi-stage cable pulley transmission system, the spring effect of the augmented counterbalancing mechanism, the major loss throughout the system elements, and the typical inertial dynamics of the robot. Next, a task space impedance controller based on limited information about the angle and the current of the motors is designed. The motor current is used to infer the transmitted torque, by which the motor inertia may be modulated. The motor angle is employed to estimate the stationary distal robot link angle and the robot joint velocity. They are used in the controller to generate the desired damping force and to shape the potential energy of the flexible joint robot system to the desired configuration. Simulation and experimental results of the controlled system signify the competency of the proposed control law.

  9. Internal and external force-based impedance control for cooperative manipulation

    NARCIS (Netherlands)

    Heck, D.J.F.; Kostic, D.; Denasi, A.; Nijmeijer, H.

    2013-01-01

    An asymptotically stable cascaded control algorithm is proposed for cooperative manipulation of a common object. This algorithm controls motion and internal forces of the object, as well as the contact forces between the object and environment. The motion of each manipulator is controlled using an

  10. A novel multi-drive electric vehicle system control based on multi-input multi-output PID controller

    Directory of Open Access Journals (Sweden)

    Gasbaoui Brahim

    2012-01-01

    Full Text Available In-wheel-motor drive electric vehicle (EV is an innovative configuration of the modern EV, in which each wheel is driven individually by an electric motor. The classical traction motor control called the Independent Machine Control Structure (IMCS using a PID speed controller presents major inconveniences in modern EV safety, when the proposed control can not ensure stability of the EV with differing road topology and variations of speed. A new approach is proposed for a control of a two-in-wheel-motor drive EV, called the Maximum Control Structure MCS. This is based on a multivariable PID (MIMO-PID strategy, which is employed to estimate the linear speed error of each of the two back driving wheels, when the error of each wheel is taken into account in the other speed control computations. Simulation results show that the new control system presents increased safety for the EVs compared with the IMCS strategy and can maintain the error slip rate within the optimal range, ensuring the stability of the vehicle either in a straight or a curved line.

  11. Controlled evaluation of silver nanoparticle dissolution using atomic force microscopy.

    Science.gov (United States)

    Kent, Ronald D; Vikesland, Peter J

    2012-07-03

    Incorporation of silver nanoparticles (AgNPs) into an increasing number of consumer products has led to concern over the potential ecological impacts of their unintended release to the environment. Dissolution is an important environmental transformation that affects the form and concentration of AgNPs in natural waters; however, studies on AgNP dissolution kinetics are complicated by nanoparticle aggregation. Herein, nanosphere lithography (NSL) was used to fabricate uniform arrays of AgNPs immobilized on glass substrates. Nanoparticle immobilization enabled controlled evaluation of AgNP dissolution in an air-saturated phosphate buffer (pH 7.0, 25 °C) under variable NaCl concentrations in the absence of aggregation. Atomic force microscopy (AFM) was used to monitor changes in particle morphology and dissolution. Over the first day of exposure to ≥10 mM NaCl, the in-plane AgNP shape changed from triangular to circular, the sidewalls steepened, the in-plane radius decreased by 5-11 nm, and the height increased by 6-12 nm. Subsequently, particle height and in-plane radius decreased at a constant rate over a 2-week period. Dissolution rates varied linearly from 0.4 to 2.2 nm/d over the 10-550 mM NaCl concentration range tested. NaCl-catalyzed dissolution of AgNPs may play an important role in AgNP fate in saline waters and biological media. This study demonstrates the utility of NSL and AFM for the direct investigation of unaggregated AgNP dissolution.

  12. Layered Multi-mode Optimal Control Strategy for Multi-MW Wind Turbine

    Institute of Scientific and Technical Information of China (English)

    KONG Yi-gang; WANG Zhi-xin

    2008-01-01

    The control strategy is one of the most important renewable technology, and an increasing number of multi-MW wind turbines are being developed with a variable speed-variable pitch (VS-VP) technology. The main objective of adopting a VS-VP technology is to improve the fast response speed and capture maximum energy. But the power generated by wind turbine changes rapidly because of the centinuous fluctuation of wind speed and direction. At the same time, wind energy conversion systems are of high order, time delays and strong nonlinear characteristics because of many uncertain factors. Based on analyzing the all dynamic processes of wind turbine, a kind of layered multi-mode optimal control strategy is presented which is that three control strategies: bang-bang, fuzzy and adaptive proportienai integral derivative (PID) are adopted according to different stages and expected performance of wind turbine to capture optimum wind power, compensate the nonlinearity and improve the wind turbine performance at low, rated and high wind speed.

  13. Visually aided force control with fuzzy parameter tuning

    OpenAIRE

    Çallı, Berk; Calli, Berk

    2008-01-01

    Vision and force sensors provide rich information which can enable robots to execute complex tasks. The integration of these two types of sensors may prove very useful in many industrial robotic applications, as well as for the robots that operate in environments where humans live. Vision sensors give robots the ability to operate in complex and dynamic environments. With force sensors contacts can be detected, and manipulation tasks can be done without the risk of damaging the workpiece. The...

  14. Force-controlled adjustment of car body fixtures

    OpenAIRE

    Keller, Carsten

    2014-01-01

    Production technology in modern car body assembling is affected by highly automated and complex facilities. However, in mounting car body assemblies adjustments are always necessary to react on quality instabilities of the input parts. Today these adjustments are made according to experience and with a high content of manual operation. This paper describes an innovative method that detects part deformations in a force sensitive way following the works of Dr. Muck, who developed a force sensit...

  15. In-depth Study on Cylinder Wake Controlled by Lorentz Force

    International Nuclear Information System (INIS)

    Zhang Hui; Fan Bao-Chun; Chen Zhi-Hua

    2011-01-01

    The underlying mechanisms of the electromagnetic control of cylinder wake are investigated and discussed. The effects of Lorentz force are found to be composed of two parts, one is its direct action on the cylinder (the wall Lorentz force) and the other is applied to the fluid (called the field Lorentz force) near the cylinder surface. Our results show that the wall Lorentz force can generate thrust and reduce the drag; the field Lorentz force increases the drag. However, the cylinder drag is dominated by the wall Lorentz force. In addition, the field Lorentz force above the upper surface decreases the lift, while the upper wall Lorentz force increases it. The total lift is dominated by the upper wall Lorentz force. (fundamental areas of phenomenology(including applications))

  16. Workspace Safe Operation of a Force- or Impedance-Controlled Robot

    Science.gov (United States)

    Abdallah, Muhammad E. (Inventor); Hargrave, Brian (Inventor); Yamokoski, John D. (Inventor); Strawser, Philip A. (Inventor)

    2013-01-01

    A method of controlling a robotic manipulator of a force- or impedance-controlled robot within an unstructured workspace includes imposing a saturation limit on a static force applied by the manipulator to its surrounding environment, and may include determining a contact force between the manipulator and an object in the unstructured workspace, and executing a dynamic reflex when the contact force exceeds a threshold to thereby alleviate an inertial impulse not addressed by the saturation limited static force. The method may include calculating a required reflex torque to be imparted by a joint actuator to a robotic joint. A robotic system includes a robotic manipulator having an unstructured workspace and a controller that is electrically connected to the manipulator, and which controls the manipulator using force- or impedance-based commands. The controller, which is also disclosed herein, automatically imposes the saturation limit and may execute the dynamic reflex noted above.

  17. Passivity-Based Control of Multi-Terminal HVDC Systems under Control Saturation Constraints

    NARCIS (Netherlands)

    Doria-Cerezo, Arnau; Olm, Josep M.; Scherpen, Jacquelien M.A.

    2015-01-01

    This paper proposes a decentralized, passivity-based control design for power stations in a multi-terminal High Voltage Direct Current transmission system. The control algorithm is shown to asymptotically stabilize the closed-loop system when the voltage set points are appropriately selected. The

  18. On the design of multi-rate tracking controllers : application to rotorcraft guidance and control

    NARCIS (Netherlands)

    Guerreiro Tome Antunes, D.J.; Silvestre, C.J.; Cunha, R.

    2010-01-01

    This paper presents a new methodology for the design and implementation of gain-scheduled controllers for multi-rate systems. The proposed methodology provides a natural way to address the integrated guidance and control problem for autonomous vehicles when the outputs are sampled at different

  19. System Interconnect Bus (SIB) compatible multi crate CAMAC Controller (CC)

    International Nuclear Information System (INIS)

    Jha, K.; Borkar, S.P.; Ghodgaonkar, M.D.; D'Costa, C.

    2001-01-01

    This paper describes design of SIB compatible crate controller with PC interface. SIB is a general-purpose parallel 1/O interface bus used for connecting multi crate system with single PC-interface. The crate controller comprises of a dedicated PC-AT add-on SIB interface card and two width CAMAC module designed to work at station 24 and station 25 of CAMAC crate. PC Interface card (SIBINT) is used for communication between PC/AT host computer and CAMAC Crates. The controller module incorporates a set of registers, logic to generate CAMAC data way timing. Transmission protocol used is RS485 standard. This controller is used for multiple CAMAC crates system, interfaced to PC, using a 60 core twisted pair flat ribbon cable. The crate controller is developed for use in process control, general-purpose data acquisition and control system and laboratory automation. Sustained data transfer rate achieved by controller is 115 Kword/sec each word being 32 bits in length. (author)

  20. Identification and Reconfigurable Control of Impaired Multi-Rotor Drones

    Science.gov (United States)

    Stepanyan, Vahram; Krishnakumar, Kalmanje; Bencomo, Alfredo

    2016-01-01

    The paper presents an algorithm for control and safe landing of impaired multi-rotor drones when one or more motors fail simultaneously or in any sequence. It includes three main components: an identification block, a reconfigurable control block, and a decisions making block. The identification block monitors each motor load characteristics and the current drawn, based on which the failures are detected. The control block generates the required total thrust and three axis torques for the altitude, horizontal position and/or orientation control of the drone based on the time scale separation and nonlinear dynamic inversion. The horizontal displacement is controlled by modulating the roll and pitch angles. The decision making algorithm maps the total thrust and three torques into the individual motor thrusts based on the information provided by the identification block. The drone continues the mission execution as long as the number of functioning motors provide controllability of it. Otherwise, the controller is switched to the safe mode, which gives up the yaw control, commands a safe landing spot and descent rate while maintaining the horizontal attitude.

  1. Iterative learning control for multi-agent systems coordination

    CERN Document Server

    Yang, Shiping; Li, Xuefang; Shen, Dong

    2016-01-01

    A timely guide using iterative learning control (ILC) as a solution for multi-agent systems (MAS) challenges, this book showcases recent advances and industrially relevant applications. Readers are first given a comprehensive overview of the intersection between ILC and MAS, then introduced to a range of topics that include both basic and advanced theoretical discussions, rigorous mathematics, engineering practice, and both linear and nonlinear systems. Through systematic discussion of network theory and intelligent control, the authors explore future research possibilities, develop new tools, and provide numerous applications such as power grids, communication and sensor networks, intelligent transportation systems, and formation control. Readers will gain a roadmap of the latest advances in the fields and can use their newfound knowledge to design their own algorithms.

  2. Learning to push and learning to move: The adaptive control of contact forces

    Directory of Open Access Journals (Sweden)

    Maura eCasadio

    2015-11-01

    Full Text Available To be successful at manipulating objects one needs to apply simultaneously well controlled movements and contact forces. We present a computational theory of how the brain may successfully generate a vast spectrum of interactive behaviors by combining two independent processes. One process is competent to control movements in free space and the other is competent to control contact forces against rigid constraints. Free space and rigid constraints are singularities at the boundaries of a continuum of mechanical impedance. Within this continuum, forces and motions occur in compatible pairs connected by the equations of Newtonian dynamics. The force applied to an object determines its motion. Conversely, inverse dynamics determine a unique force trajectory from a movement trajectory. In this perspective, we describe motor learning as a process leading to the discovery of compatible force/motion pairs. The learned compatible pairs constitute a local representation of the environment's mechanics. Experiments on force field adaptation have already provided us with evidence that the brain is able to predict and compensate the forces encountered when one is attempting to generate a motion. Here, we tested the theory in the dual case, i.e. when one attempts at applying a desired contact force against a simulated rigid surface. If the surface becomes unexpectedly compliant, the contact point moves as a function of the applied force and this causes the applied force to deviate from its desired value. We found that, through repeated attempts at generating the desired contact force, subjects discovered the unique compatible hand motion. When, after learning, the rigid contact was unexpectedly restored, subjects displayed after effects of learning, consistent with the concurrent operation of a motion control system and a force control system. Together, theory and experiment support a new and broader view of modularity in the coordinated control of forces and

  3. Voltage margin control for offshore multi-use platform integration

    DEFF Research Database (Denmark)

    Mier, V.; Casielles, P.G.; Koto, J.

    This paper discusses a multiterminal direct current (MTDC) connection proposed for integration of offshore multi-use platforms into continental grids. Voltage source converters (VSC) were selected for their suitability for multiterminal dc systems and for their flexibility in control. A five...... terminal VSC-MTDC which includes offshore generation, storage, loads and ac connection, was modeled and simulated in DigSILENT Power Factory software. Voltage margin method has been used for reliable operation of the MTDC system without the need of fast communication. Simulation results show......, sell or store energy attending to the price in the electricity market....

  4. Investigation, sensitivity analysis, and multi-objective optimization of effective parameters on temperature and force in robotic drilling cortical bone.

    Science.gov (United States)

    Tahmasbi, Vahid; Ghoreishi, Majid; Zolfaghari, Mojtaba

    2017-11-01

    The bone drilling process is very prominent in orthopedic surgeries and in the repair of bone fractures. It is also very common in dentistry and bone sampling operations. Due to the complexity of bone and the sensitivity of the process, bone drilling is one of the most important and sensitive processes in biomedical engineering. Orthopedic surgeries can be improved using robotic systems and mechatronic tools. The most crucial problem during drilling is an unwanted increase in process temperature (higher than 47 °C), which causes thermal osteonecrosis or cell death and local burning of the bone tissue. Moreover, imposing higher forces to the bone may lead to breaking or cracking and consequently cause serious damage. In this study, a mathematical second-order linear regression model as a function of tool drilling speed, feed rate, tool diameter, and their effective interactions is introduced to predict temperature and force during the bone drilling process. This model can determine the maximum speed of surgery that remains within an acceptable temperature range. Moreover, for the first time, using designed experiments, the bone drilling process was modeled, and the drilling speed, feed rate, and tool diameter were optimized. Then, using response surface methodology and applying a multi-objective optimization, drilling force was minimized to sustain an acceptable temperature range without damaging the bone or the surrounding tissue. In addition, for the first time, Sobol statistical sensitivity analysis is used to ascertain the effect of process input parameters on process temperature and force. The results show that among all effective input parameters, tool rotational speed, feed rate, and tool diameter have the highest influence on process temperature and force, respectively. The behavior of each output parameters with variation in each input parameter is further investigated. Finally, a multi-objective optimization has been performed considering all the

  5. Control method for multi-input multi-output non-Gaussian random vibration test with cross spectra consideration

    Directory of Open Access Journals (Sweden)

    Ronghui ZHENG

    2017-12-01

    Full Text Available A control method for Multi-Input Multi-Output (MIMO non-Gaussian random vibration test with cross spectra consideration is proposed in the paper. The aim of the proposed control method is to replicate the specified references composed of auto spectral densities, cross spectral densities and kurtoses on the test article in the laboratory. It is found that the cross spectral densities will bring intractable coupling problems and induce difficulty for the control of the multi-output kurtoses. Hence, a sequential phase modification method is put forward to solve the coupling problems in multi-input multi-output non-Gaussian random vibration test. To achieve the specified responses, an improved zero memory nonlinear transformation is utilized first to modify the Fourier phases of the signals with sequential phase modification method to obtain one frame reference response signals which satisfy the reference spectra and reference kurtoses. Then, an inverse system method is used in frequency domain to obtain the continuous stationary drive signals. At the same time, the matrix power control algorithm is utilized to control the spectra and kurtoses of the response signals further. At the end of the paper, a simulation example with a cantilever beam and a vibration shaker test are implemented and the results support the proposed method very well. Keywords: Cross spectra, Kurtosis control, Multi-input multi-output, Non-Gaussian, Random vibration test

  6. Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

    Science.gov (United States)

    Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

    2014-09-01

    In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

  7. An intelligent active force control algorithm to control an upper extremity exoskeleton for motor recovery

    Science.gov (United States)

    Hasbullah Mohd Isa, Wan; Taha, Zahari; Mohd Khairuddin, Ismail; Majeed, Anwar P. P. Abdul; Fikri Muhammad, Khairul; Abdo Hashem, Mohammed; Mahmud, Jamaluddin; Mohamed, Zulkifli

    2016-02-01

    This paper presents the modelling and control of a two degree of freedom upper extremity exoskeleton by means of an intelligent active force control (AFC) mechanism. The Newton-Euler formulation was used in deriving the dynamic modelling of both the anthropometry based human upper extremity as well as the exoskeleton that consists of the upper arm and the forearm. A proportional-derivative (PD) architecture is employed in this study to investigate its efficacy performing joint-space control objectives. An intelligent AFC algorithm is also incorporated into the PD to investigate the effectiveness of this hybrid system in compensating disturbances. The Mamdani Fuzzy based rule is employed to approximate the estimated inertial properties of the system to ensure the AFC loop responds efficiently. It is found that the IAFC-PD performed well against the disturbances introduced into the system as compared to the conventional PD control architecture in performing the desired trajectory tracking.

  8. PC-based digital feedback control for scanning force microscope

    International Nuclear Information System (INIS)

    Mohd Ashhar Khalid

    2002-01-01

    In the past, most digital feedback implementation for scanned-probe microscope were based on a digital signal processor (DSP). At present DSP plug-in card with the input-output interface module is still expensive compared to a fast pentium PC motherboard. For a magnetic force microscope (MFM) digital feedback has an advantage where the magnetic signal can be easily separated from the topographic signal. In this paper, a simple low-cost PC-based digital feedback and imaging system for Scanning Force Microscope (SFM) is presented. (Author)

  9. Theoretical and algorithmic advances in multi-parametric programming and control

    KAUST Repository

    Pistikopoulos, Efstratios N.; Dominguez, Luis; Panos, Christos; Kouramas, Konstantinos; Chinchuluun, Altannar

    2012-01-01

    This paper presents an overview of recent theoretical and algorithmic advances, and applications in the areas of multi-parametric programming and explicit/multi-parametric model predictive control (mp-MPC). In multi-parametric programming, advances include areas such as nonlinear multi-parametric programming (mp-NLP), bi-level programming, dynamic programming and global optimization for multi-parametric mixed-integer linear programming problems (mp-MILPs). In multi-parametric/explicit MPC (mp-MPC), advances include areas such as robust multi-parametric control, multi-parametric nonlinear MPC (mp-NMPC) and model reduction in mp-MPC. A comprehensive framework for multi-parametric programming and control is also presented. Recent applications include a hydrogen storage device, a fuel cell power generation system, an unmanned autonomous vehicle (UAV) and a hybrid pressure swing adsorption (PSA) system. © 2012 Springer-Verlag.

  10. Theoretical and algorithmic advances in multi-parametric programming and control

    KAUST Repository

    Pistikopoulos, Efstratios N.

    2012-04-21

    This paper presents an overview of recent theoretical and algorithmic advances, and applications in the areas of multi-parametric programming and explicit/multi-parametric model predictive control (mp-MPC). In multi-parametric programming, advances include areas such as nonlinear multi-parametric programming (mp-NLP), bi-level programming, dynamic programming and global optimization for multi-parametric mixed-integer linear programming problems (mp-MILPs). In multi-parametric/explicit MPC (mp-MPC), advances include areas such as robust multi-parametric control, multi-parametric nonlinear MPC (mp-NMPC) and model reduction in mp-MPC. A comprehensive framework for multi-parametric programming and control is also presented. Recent applications include a hydrogen storage device, a fuel cell power generation system, an unmanned autonomous vehicle (UAV) and a hybrid pressure swing adsorption (PSA) system. © 2012 Springer-Verlag.

  11. Optimization of Easy Atomic Force Microscope (ezAFM) Controls for Semiconductor Nanostructure Profiling

    Science.gov (United States)

    2017-09-01

    ARL-MR-0965 ● SEP 2017 US Army Research Laboratory Optimization of Easy Atomic Force Microscope (ezAFM) Controls for... Optimization of Easy Atomic Force Microscope (ezAFM) Controls for Semiconductor Nanostructure Profiling by Satwik Bisoi Science and...REPORT TYPE Memorandum Report 3. DATES COVERED (From - To) 2017 July 05–2017 August 18 4. TITLE AND SUBTITLE Optimization of Easy Atomic Force

  12. Hybrid Force Control Based on ICMAC for an Astronaut Rehabilitative Training Robot

    OpenAIRE

    Lixun Zhang; Yupeng Zou; Lan Wang; Xinping Pei

    2012-01-01

    A novel Astronaut Rehabilitative Training Robot (ART) based on a cable‐driven mechanism is represented in this paper. ART, a typical passive force servo system, can help astronauts to bench press in a microgravity environment. The purpose of this paper is to design controllers to eliminate the surplus force caused by an astronaut’s active movements. Based on the dynamics modelling of the cable‐driven unit, a hybrid force controller based on improved credit assignment CMAC (ICMAC) is presented...

  13. Energy management and multi-layer control of networked microgrids

    Science.gov (United States)

    Zamora, Ramon

    Networked microgrids is a group of neighboring microgrids that has ability to interchange power when required in order to increase reliability and resiliency. Networked microgrid can operate in different possible configurations including: islanded microgrid, a grid-connected microgrid without a tie-line converter, a grid-connected microgrid with a tie-line converter, and networked microgrids. These possible configurations and specific characteristics of renewable energy offer challenges in designing control and management algorithms for voltage, frequency and power in all possible operating scenarios. In this work, control algorithm is designed based on large-signal model that enables microgrid to operate in wide range of operating points. A combination between PI controller and feed-forward measured system responses will compensate for the changes in operating points. The control architecture developed in this work has multi-layers and the outer layer is slower than the inner layer in time response. The main responsibility of the designed controls are to regulate voltage magnitude and frequency, as well as output power of the DG(s). These local controls also integrate with a microgrid level energy management system or microgrid central controller (MGCC) for power and energy balance for. the entire microgrid in islanded, grid-connected, or networked microgid mode. The MGCC is responsible to coordinate the lower level controls to have reliable and resilient operation. In case of communication network failure, the decentralized energy management will operate locally and will activate droop control. Simulation results indicate the superiority of designed control algorithms compared to existing ones.

  14. Dynamics modeling for parallel haptic interfaces with force sensing and control.

    Science.gov (United States)

    Bernstein, Nicholas; Lawrence, Dale; Pao, Lucy

    2013-01-01

    Closed-loop force control can be used on haptic interfaces (HIs) to mitigate the effects of mechanism dynamics. A single multidimensional force-torque sensor is often employed to measure the interaction force between the haptic device and the user's hand. The parallel haptic interface at the University of Colorado (CU) instead employs smaller 1D force sensors oriented along each of the five actuating rods to build up a 5D force vector. This paper shows that a particular manipulandum/hand partition in the system dynamics is induced by the placement and type of force sensing, and discusses the implications on force and impedance control for parallel haptic interfaces. The details of a "squaring down" process are also discussed, showing how to obtain reduced degree-of-freedom models from the general six degree-of-freedom dynamics formulation.

  15. Differences in grip force control between young and late middle-aged adults.

    Science.gov (United States)

    Zheng, Lianrong; Li, Kunyang; Wang, Qian; Chen, Wenhui; Song, Rong; Liu, Guanzheng

    2017-09-01

    Grip force control is a crucial function for human to guarantee the quality of life. To examine the effects of age on grip force control, 10 young adults and 11 late middle-aged adults participated in visually guided tracking tasks using different target force levels (25, 50, and 75% of the subject's maximal grip force). Multiple measures were used to evaluate the tracking performance during force rising phase and force maintenance phase. The measurements include the rise time, fuzzy entropy, mean force percentage, coefficient of variation, and target deviation ratio. The results show that the maximal grip force was significantly lower in the late middle-aged adults than in the young adults. The time of rising phase was systematically longer among late middle-aged adults. The fuzzy entropy is a useful indicator for quantitating the force variability of the grip force signal at higher force levels. These results suggest that the late middle-aged adults applied a compensatory strategy that allow allows for sufficient time to reach the required grip force and reduce the impact of the early and subtle degenerative changes in hand motor function.

  16. Force Myography to Control Robotic Upper Extremity Prostheses: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Erina eCho

    2016-03-01

    Full Text Available Advancement in assistive technology has led to the commercial availability of multi-dexterous robotic prostheses for the upper extremity. The relatively low performance of the currently used techniques to detect the intention of the user to control such advanced robotic prostheses, however, limits their use. This article explores the use of force myography (FMG as a potential alternative to the well-established surface electro-myography (sEMG. Specifically, the use of FMG to control different grips of a commercially available robotic hand, Bebionic3, are investigated. Four male transradially amputated subjects participated in the study and a protocol was developed to assess the prediction accuracy of eleven grips. Different combinations of grips were examined ranging from six up to eleven grips. The results indicate that it is possible to classify six primary grips important in activities of daily living using FMG with an accuracy of above 70% in the residual limb. Additional strategies to increase classification accuracy, such as using the available modes on the Bebionic3, allowed results to improve up to 88.83% and 89.00% for opposed thumb and non-opposed thumb modes respectively.

  17. Rapid fabricating technique for multi-layered human hepatic cell sheets by forceful contraction of the fibroblast monolayer.

    Directory of Open Access Journals (Sweden)

    Yusuke Sakai

    Full Text Available Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.

  18. Control over multiscale mixing in broadband-forced turbulence

    NARCIS (Netherlands)

    Kuczaj, Arkadiusz K.; Geurts, Bernardus J.

    2008-01-01

    The effects of explicit flow modulation on the dispersion of a passive scalar field are studied. Broadband forcing is applied to homogeneous isotropic turbulence to modulate the energy cascading and alter the kinetic energy spectrum. Consequently, a manipulation of turbulent flow can be achieved

  19. Tuning method for multi-variable control system with PID controllers

    International Nuclear Information System (INIS)

    Fujiwara, Toshitaka

    1983-01-01

    Control systems, including thermal and nuclear power plants, generally and mainly use PID controllers consisting of proportional, integral and differential actions. These systems consist of multiple control loops which interfere with each other. Therefore, it is present status that the fine control of the system is carried out by the trial and error method because the adjusting procedure for a single control loop cannot be applied to a multi-loop system in most cases. In this report, a method to effectively adjust PID controller parameters in a short time in a control system which consists of multi-loops that interfere with each other. This method makes adjustment by using the control area as the evaluation function, which is the time-dependent integration of control deviation, the input to the PID controllers. In other words, the evaluation function is provided for each control result for every parameter (gain constant, reset rate, and differentiation time), and all parameters are simultaneously changed in the direction of minimizing the values of these evaluation functions. In the report, the principle of tuning method, the evaluation function for each of three parameters, and the adjusting system configuration for separately using for actual plant tuning and for control system design are described. It also shows the examples of application to the actual tuning of the control system for a thermal power plant and to a control system design. (Wakatsuki, Y.)

  20. Grasping an augmented object to analyse manipulative force control.

    Science.gov (United States)

    Kawai, Satoru; Summers, Valerie A; Mackenzie, Christine L; Ivens, Chris J; Yamamoto, Takashi

    2002-12-15

    Augmented reality allows changes to be made to the visual perception of object size even while the tangible components remain completely unaltered. It was, therefore, utilized in a study whose results are being reported here to provide the proper environment required to thoroughly observe the exact effect that visual change to object size had on programming fingertip forces when objects were lifted with a precision grip. Twenty-one participants performed repeated lifts of an identical grip apparatus to a height of 20 mm, maintained each lift for 8 seconds, and then replaced the grip apparatus on the table. While all other factors of the grip apparatus remained unchanged, visual appearance was altered graphically in a 3-D augmented environment. The grip apparatus measured grip and load forces independently. Grip and load forces demonstrated significant rates of increase as well as peak forces as the size of graphical images increased; an aspect that occurred in spite of the fact that extraneous haptic information remained constant throughout the trials. By indicating a human tendency to rely - even unconsciously - on visual input to program the forces in the initial lifting phase, this finding provides further confirmation of previous research findings obtained in the physical environment; including the possibility of extraneous haptic effects (Gordon et al. 1991a, Mon-Williams and Murray 2000, Kawai et al. 2000). The present results also suggest that existing knowledge concerning human manipulation tasks in the physical world may be applied to an augmented environment where the physical objects are enhanced by computer generated visual components.

  1. FORCE STRUCTURE: Better Management Controls Are Needed to Oversee the Army's Modular Force and Expansion Initiatives and Improve Accountability for Results

    National Research Council Canada - National Science Library

    2007-01-01

    .... For this report, GAO assessed to what extent the Army has accomplished the following: (1) implemented and established management controls for its modular force and force expansion initiatives, and (2...

  2. Hybrid Multi-Layer Network Control for Emerging Cyber-Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Summerhill, Richard [Internet2, Washington, DC (United States); Lehman, Tom [Univ. of Southern California, Los Angeles, CA (United States). Information Sciences Inst. (ISI); Ghani, Nasir [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical & Computer Engineering; Boyd, Eric [Univ. Corporation for Advanced Internet Development (UCAID), Washington, DC (United States)

    2009-08-14

    There were four basic task areas identified for the Hybrid-MLN project. They are: Multi-Layer, Multi-Domain, Control Plane Architecture and Implementation; Heterogeneous DataPlane Testing; Simulation; Project Publications, Reports, and Presentations.

  3. Control of dynamical self-assembly of strongly Brownian nanoparticles through convective forces induced by ultrafast laser

    Science.gov (United States)

    Ilday, Serim; Akguc, Gursoy B.; Tokel, Onur; Makey, Ghaith; Yavuz, Ozgun; Yavuz, Koray; Pavlov, Ihor; Ilday, F. Omer; Gulseren, Oguz

    We report a new dynamical self-assembly mechanism, where judicious use of convective and strong Brownian forces enables effective patterning of colloidal nanoparticles that are almost two orders of magnitude smaller than the laser beam. Optical trapping or tweezing effects are not involved, but the laser is used to create steep thermal gradients through multi-photon absorption, and thereby guide the colloids through convective forces. Convective forces can be thought as a positive feedback mechanism that helps to form and reinforce pattern, while Brownian motion act as a competing negative feedback mechanism to limit the growth of the pattern, as well as to increase the possibilities of bifurcation into different patterns, analogous to the competition observed in reaction-diffusion systems. By steering stochastic processes through these forces, we are able to gain control over the emergent pattern such as to form-deform-reform of a pattern, to change its shape and transport it spatially within seconds. This enables us to dynamically initiate and control large patterns comprised of hundreds of colloids. Further, by not relying on any specific chemical, optical or magnetic interaction, this new method is, in principle, completely independent of the material type being assembled.

  4. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    International Nuclear Information System (INIS)

    Kim, Hyo-gon; Han, Changsoo; Lee, Jong-won; Park, Sangdeok

    2015-01-01

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program

  5. Study on Characteristics of Hydraulic Servo System for Force Control of Hydraulic Robots

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyo-gon; Han, Changsoo [Hanyang University, Seoul (Korea, Republic of); Lee, Jong-won [Korea University of Science and Technology, Seoul (Korea, Republic of); Park, Sangdeok [Korea Institute of Industrial Technology, Seoul (Korea, Republic of)

    2015-02-15

    Because a hydraulic actuator has high power and force densities, this allows the weight of the robot's limbs to be reduced. This allows for good dynamic characteristics and high energy efficiency. Thus, hydraulic actuators are used in some exoskeleton robots and quadrupedal robots that require high torque. Force control is useful for robot compliance with a user or environment. However, force control of a hydraulic robot is difficult because a hydraulic servo system is highly nonlinear from a control perspective. In this study, a nonlinear model was used to develop a simulation program for a hydraulic servo system consisting of a servo valve, transmission lines, and a cylinder. The problems and considerations with regard to the force control performance for a hydraulic servo system were investigated. A force control method using the nonlinear model was proposed, and its effect was evaluated with the simulation program.

  6. Multi-layer cultivation in practice. Energy efficient forcing; Meerlagenteelt in de praktijk. Energie-efficienter broeien

    Energy Technology Data Exchange (ETDEWEB)

    Wildschut, J. [Praktijkonderzoek Plant en Omgeving PPO, Wageningen UR, Lisse (Netherlands); Campen, J.C. (Glastuinbouw, Wageningen UR, Wageningen (Netherlands)

    2010-11-15

    Next to possible benefits such as improved greenhouse utilization, resulting in a lower cost price and production expansion without expanding the greenhouse, multi-layer heating (in the greenhouse and/or cell) offers significant opportunities to reduce the energy use in the forcing process [Dutch] Naast mogelijke voordelen als een betere kasbenutting, waardoor een lagere kostprijs, en productieuitbreiding zonder kasuitbreiding, biedt het broeien in meerdere lagen (in de kas en/of in de cel) grote mogelijkheden om het energieverbruik in de broeierij terug te dringen.

  7. A radial distribution function-based open boundary force model for multi-centered molecules

    KAUST Repository

    Neumann, Philipp; Eckhardt, Wolfgang; Bungartz, Hans-Joachim

    2014-01-01

    We derive an expression for radial distribution function (RDF)-based open boundary forcing for molecules with multiple interaction sites. Due to the high-dimensionality of the molecule configuration space and missing rotational invariance, a

  8. Transmit Antenna Selection for Multi-User Underlay Cognitive Transmission with Zero-Forcing Beamforming

    KAUST Repository

    Hanif, Muhammad; Yang, Hong-Chuan; Alouini, Mohamed-Slim

    2017-01-01

    We present a transmit antenna subset selection scheme for an underlay cognitive system serving multiple secondary receivers. The secondary system employs zero-forcing beamforming to nullify the interference to multiple primary users and eliminate

  9. Control Design of Active Magnetic Bearings for Rotors Subjected to Destabilising Seal Forces - Theory & Experiment

    DEFF Research Database (Denmark)

    Lauridsen, Jonas Skjødt

    . At present, there is no generally accepted method for determination of dynamic seal forces. Therefore, large uncertainties must be expected when modelling dynamic seal forces and consequently also in rotor-dynamic stability analysis. This thesis focuses on i) closed loop identification of uncertain AMB...... parameters, ii) closed loop identification of unknown stiffness and damping coefficients of a dynamicseal model and iii) the design of AMB controllers to handle dynamic seal forces. Controllers that can guarantee stability and performance in the presence of uncertainseal forces are of special interest...... the uncertaintiesin seal forces and for LPV control synthesis, to compensate for known changes in seal forces due to changes in operating conditions. A rotor dynamic test facility with a rigid rotor, two radial AMBs and one annular test seal is used for i) closed loop identification of parameters in the AMB...

  10. Multi-component controllers in reactor physics optimality analysis

    International Nuclear Information System (INIS)

    Aldemir, T.

    1978-01-01

    An algorithm is developed for the optimality analysis of thermal reactor assemblies with multi-component control vectors. The neutronics of the system under consideration is assumed to be described by the two-group diffusion equations and constraints are imposed upon the state and control variables. It is shown that if the problem is such that the differential and algebraic equations describing the system can be cast into a linear form via a change of variables, the optimal control components are piecewise constant functions and the global optimal controller can be determined by investigating the properties of the influence functions. Two specific problems are solved utilizing this approach. A thermal reactor consisting of fuel, burnable poison and moderator is found to yield maximal power when the assembly consists of two poison zones and the power density is constant throughout the assembly. It is shown that certain variational relations have to be considered to maintain the activeness of the system equations as differential constraints. The problem of determining the maximum initial breeding ratio for a thermal reactor is solved by treating the fertile and fissile material absorption densities as controllers. The optimal core configurations are found to consist of three fuel zones for a bare assembly and two fuel zones for a reflected assembly. The optimum fissile material density is determined to be inversely proportional to the thermal flux

  11. Generation of synthetic surface electromyography signals under fatigue conditions for varying force inputs using feedback control algorithm.

    Science.gov (United States)

    Venugopal, G; Deepak, P; Ghosh, Diptasree M; Ramakrishnan, S

    2017-11-01

    Surface electromyography is a non-invasive technique used for recording the electrical activity of neuromuscular systems. These signals are random, complex and multi-component. There are several techniques to extract information about the force exerted by muscles during any activity. This work attempts to generate surface electromyography signals for various magnitudes of force under isometric non-fatigue and fatigue conditions using a feedback model. The model is based on existing current distribution, volume conductor relations, the feedback control algorithm for rate coding and generation of firing pattern. The result shows that synthetic surface electromyography signals are highly complex in both non-fatigue and fatigue conditions. Furthermore, surface electromyography signals have higher amplitude and lower frequency under fatigue condition. This model can be used to study the influence of various signal parameters under fatigue and non-fatigue conditions.

  12. Seamless Control of Multi-Fingered Robot Hands Based on Grasp Polyhedrons

    Science.gov (United States)

    Nagase, Kenji; Shirai, Satoshi; Hayashi, Tsuyoshi

    This paper is concerned with a new feedback control design methodology for multi-fingered robot hands applicable to multiple contact situations. As a first step, we especially consider the situations where all the fingers are in contact or not in contact with an object, considering the tasks of catching and releasing the object preceding to or followed by grasping/manipulating the object. Main features of the proposed method are: (1) the direction of the fingertip motion in the non-contact situation is selected to be directly linked to the direction of the object motion and the internal force in the contact situation; (2) by introducing a unified system description for multiple contact situations, a linearizing compensator applicable to multiple contact situations is designed. The controller can handle the tasks with the multiple contact situations by choosing appropriate desired trajectories for the linearizing compensator without switching control architecture. In addition, owing to the selection of the motion in the non-contact situation, all the fingers can approach to the object synchronously along the directions of the object motion and the internal force in the contact situation. A numerical example is shown to prove effectiveness of the proposed method.

  13. Research of a New 6-Dof Force Feedback Hand Controller System

    Directory of Open Access Journals (Sweden)

    Xin Gao

    2014-01-01

    Full Text Available The field of teleoperation with force telepresence has expanded its scope to include manipulation at different scales and in virtual worlds, and the key component of which is force feedback hand controller. This paper presents a novel force feedback hand controller system, including a 3-dof translational and 3-dof rotational hand controllers, respectively, to implement position and posture teleoperation of the robot end effector. The 3-dof translational hand controller adopts innovative three-axes decoupling structure based on the linear motor; the 3-dof rotational hand controller adopts serial mechanism based on three-axes intersecting at one point, improving its overall stiffness. Based on the kinematics, statics, and dynamics analyses for two platforms separately, the system applies big closed-loop force control method based on the zero force/torque, improving the feedback force/torque accuracy effectively. Experimental results show that self-developed 6-dof force feedback hand controller has good mechanical properties. The translational hand controller has the following advantages: simple kinematics solver, fast dynamic response, and better than 0.05 mm accuracy of three-axis end positioning, while the advantages of the rotational hand controller are wide turning space, larger than 1 Nm feedback, greater than 180 degrees of operating space of three axes, respectively, and high operation precision.

  14. The climatic out of control. the climatic forcing

    International Nuclear Information System (INIS)

    Bony-Lena, S.; Dufresne, J.L.; Acot, P.; Friedlingstein, P.; Berger, A.; Loutre, M.L.; Raynaud, D.; Thuiller, W.; Le Treut, H.; Houssais, M.N.; Duplessy, J.C.; Royer, J.F.; Douville, H.; Barberousse, A.; Quinon, P.

    2007-01-01

    The expert group on the climate evolution affirms that the global warming is unequivocal and that the human being is the main responsible. This document broaches the climatic change under many aspects: the principle, the historical aspect of the greenhouse effect, the GIEC, the carbon cycle, the paleo-climate theory, the antarctic ices and the impacts of the climatic change on the biodiversity, the simulations and the models, the climatic indicators and the climatic forcing by human activities. (A.L.B.)

  15. Design of a smart haptic system for repulsive force control under irregular manipulation environment

    International Nuclear Information System (INIS)

    Lee, Sang-Rock; Choi, Seung-Hyun; Choi, Seung-Bok; Cho, Myeong-Woo

    2014-01-01

    This paper describes how to make an operator feel the desired repulsive force in a haptic system. When an operator manipulates a haptic system, the repulsive force of the operator varies significantly, depending on many factors such as position, velocity and force. In order to reflect the desired repulsive force to the operator, it is commonly known that a haptic system must compensate for irregularly changing forces. The irregularity of the forces, however, has discouraged many researchers from establishing a clear principle on how to make the operator feel the desired repulsive force. To resolve this problem, we introduce a smart haptic framework that can reflect the desired repulsive force to the operator, regardless of the operator’s movement. A dummy governing equation technique is introduced and used to calculate the proper actuating force in real time. The actuating force is generated by a PID controller. To verify the proposed method, a mathematical proof is offered to show that the repulsive force converges to the desired repulsive force. Additionally, to demonstrate the performance of the proposed method, simulational and experimental tests are implemented. (paper)

  16. Position and force control of a vehicle with two or more steerable drive wheels

    Energy Technology Data Exchange (ETDEWEB)

    Reister, D.B.; Unseren, M.A.

    1992-10-01

    When a vehicle with two or more steerable drive wheels is traveling in a circle, the motion of the wheels is constrained. The wheel translational velocity divided by the radius to the center of rotation must be the same for all wheels. When the drive wheels are controlled independently using position control, the motion of the wheels may violate the constraints and the wheels may slip. Consequently, substantial errors can occur in the orientation of the vehicle. A vehicle with N drive wheels has (N - 1) constraints and one degree of freedom. We have developed a new approach to the control of a vehicle with N steerable drive wheels. The novel aspect of our approach is the use of force control. To control the vehicle, we have one degree of freedom for the position on the circle and (N - 1) forces that can be used to reduce errors. Recently, Kankaanranta and Koivo developed a control architecture that allows the force and position degrees of freedom to be decoupled. In the work of Kankaanranta and Koivo the force is an exogenous input. We have made the force endogenous by defining the force in terms of the errors in satisfying the rigid body kinematic constraints. We have applied the control architecture to the HERMIES-III robot and have measured a dramatic reduction in error (more than a factor of 20) compared to motions without force control.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. Multi-body simulation of a canine hind limb: model development, experimental validation and calculation of ground reaction forces

    Directory of Open Access Journals (Sweden)

    Wefstaedt Patrick

    2009-11-01

    Full Text Available Abstract Background Among other causes the long-term result of hip prostheses in dogs is determined by aseptic loosening. A prevention of prosthesis complications can be achieved by an optimization of the tribological system which finally results in improved implant duration. In this context a computerized model for the calculation of hip joint loadings during different motions would be of benefit. In a first step in the development of such an inverse dynamic multi-body simulation (MBS- model we here present the setup of a canine hind limb model applicable for the calculation of ground reaction forces. Methods The anatomical geometries of the MBS-model have been established using computer tomography- (CT- and magnetic resonance imaging- (MRI- data. The CT-data were collected from the pelvis, femora, tibiae and pads of a mixed-breed adult dog. Geometric information about 22 muscles of the pelvic extremity of 4 mixed-breed adult dogs was determined using MRI. Kinematic and kinetic data obtained by motion analysis of a clinically healthy dog during a gait cycle (1 m/s on an instrumented treadmill were used to drive the model in the multi-body simulation. Results and Discussion As a result the vertical ground reaction forces (z-direction calculated by the MBS-system show a maximum deviation of 1.75%BW for the left and 4.65%BW for the right hind limb from the treadmill measurements. The calculated peak ground reaction forces in z- and y-direction were found to be comparable to the treadmill measurements, whereas the curve characteristics of the forces in y-direction were not in complete alignment. Conclusion In conclusion, it could be demonstrated that the developed MBS-model is suitable for simulating ground reaction forces of dogs during walking. In forthcoming investigations the model will be developed further for the calculation of forces and moments acting on the hip joint during different movements, which can be of help in context with the in

  2. Study on electromagnetism force of CARR control rod drive mechanism experimental machine

    International Nuclear Information System (INIS)

    Zhu Xuewei; Zhen Jianxiao; Wang Yulin; Jia Yueguang; Yang Kun; Yin Haozhe

    2015-01-01

    With the aim of acquiring electromagnetic force and electromagnetic field distributions of control rod drive mechanism (CRDM) in China Advanced Research Reactor (CARR), the force analysis on the CRDM was taken. Manufacturing the experimental machine, the electromagnetic force experiment was taken on it. The electromagnetic field and electromagnetic force simulation analyses of experimental machine were taken, working out distribution data of electromagnetic force and magnetic induction intensity distribution curve, and the effects of permanent magnetic field on electromagnetic field and structure parameters on electromagnetic force. The simulation value is accord with experiment value, the research results provide a reference to electromagnetic force study on CRDM in CARR, and also provide a reference to design of the same type CRDM. (authors)

  3. Control system for a multi-joint inspection robot

    International Nuclear Information System (INIS)

    Asano, K.

    1984-01-01

    Remote systems, in which a human operator in a safe zone determines pertinent circumstances and makes decisions on work procedures, while a robot does direct work in hazardous environments, have been becoming more and more important in accordance with the increase in nuclear facilities. In such remote systems, to perform tasks which are merely ambiguously defined beforehand, it is very important that the systems have the ability to execute desired tasks easily and immediately without any programming or teaching work on the spot. A control system, named Self Approach System (SAS), for a multi-joint inspection robot has been developed as a key component in a remote inspection system for use in physically difficult or dangerous environments. It has 8 joints and 17 degrees-of-freedom and was designed taking many of the above points into account. This paper describes SAS details

  4. Additive Manufacturing: Multi Material Processing and Part Quality Control

    DEFF Research Database (Denmark)

    Pedersen, David Bue

    This Ph.D dissertation,ffAdditive Manufacturing: Multi Material Processing and Part Quality Controlff, deal with Additive Manufacturing technologies which is a common name for a series of processes that are recognized by being computer controlled, highly automated, and manufacture objects...... by a layered deposition of material. Two areas of particular interest is addressed. They are rooted in two very different areas, yet is intended to fuel the same goal. To help Additive Manufacturing technologies one step closer to becoming the autonomous, digital manufacturing method of tomorrow. Vision...... systems A paradox exist in the field of Additive Manufacturing. The technologies allow for close-to unrestrained and integral geometrical freedom. Almost any geometry can be manufactured fast, e"ciently and cheap. Something that has been missing fundamental capability since the entering of the industrial...

  5. Approaching Incast Congestion with Multi-host Ethernet Controllers

    CERN Document Server

    Jereczek, Grzegorz Edmund; The ATLAS collaboration

    2018-01-01

    The bursty many-to-one communication pattern, typical for data acquisition systems, but also present in datacenter networks, is particularly demanding for commodity TCP/IP and Ethernet technologies. We expand our study of building incast-resistant networks based on software switches running on commercial-off-the-shelf servers. In this paper we provide the estimates for costs and physical area required to build such a network. Our estimates indicate that our proposed design offers significant cost advantage over traditional solutions, but higher space utilisation. Next, we show how the latter can be improved with multi-host Ethernet controllers, as an alternative to typical network interface cards. This can also make software switching easier to adapt in datacenter as a solution for incast congestion. We confirm the capabilities for incast-avoidance by evaluating the performance of a reference platform.

  6. Approaching Incast Congestion with Multi-host Ethernet Controllers

    CERN Document Server

    AUTHOR|(SzGeCERN)698154; The ATLAS collaboration; Lehmann Miotto, Giovanna; Malone, David; Walukiewicz, Miroslaw

    2017-01-01

    The bursty many-to-one communication pattern, typical for data acquisition systems, but also present in datacenter networks, is particularly demanding for commodity TCP/IP and Ethernet technologies. We expand our study of building incast-resistant networks based on software switches running on commercial-off-the-shelf servers. In this paper we provide the estimates for costs and physical area required to build such a network. Our estimates indicate that our proposed design offers significant cost advantage over traditional solutions, but higher space utilisation. Next, we show how the latter can be improved with multi-host Ethernet controllers, as an alternative to typical network interface cards. This can also make software switching easier to adapt in datacenter as a solution for incast congestion. We confirm the capabilities for incast-avoidance by evaluating the performance of a reference platform.

  7. A Multi-Agent Control Architecture for a Robotic Wheelchair

    Directory of Open Access Journals (Sweden)

    C. Galindo

    2006-01-01

    Full Text Available Assistant robots like robotic wheelchairs can perform an effective and valuable work in our daily lives. However, they eventually may need external help from humans in the robot environment (particularly, the driver in the case of a wheelchair to accomplish safely and efficiently some tricky tasks for the current technology, i.e. opening a locked door, traversing a crowded area, etc. This article proposes a control architecture for assistant robots designed under a multi-agent perspective that facilitates the participation of humans into the robotic system and improves the overall performance of the robot as well as its dependability. Within our design, agents have their own intentions and beliefs, have different abilities (that include algorithmic behaviours and human skills and also learn autonomously the most convenient method to carry out their actions through reinforcement learning. The proposed architecture is illustrated with a real assistant robot: a robotic wheelchair that provides mobility to impaired or elderly people.

  8. Adaptive control in multi-threaded iterated integration

    International Nuclear Information System (INIS)

    Doncker, Elise de; Yuasa, Fukuko

    2013-01-01

    In recent years we have developed a technique for the direct computation of Feynman loop-integrals, which are notorious for the occurrence of integrand singularities. Especially for handling singularities in the interior of the domain, we approximate the iterated integral using an adaptive algorithm in the coordinate directions. We present a novel multi-core parallelization scheme for adaptive multivariate integration, by assigning threads to the rule evaluations in the outer dimensions of the iterated integral. The method ensures a large parallel granularity as each function evaluation by itself comprises an integral over the lower dimensions, while the application of the threads is governed by the adaptive control in the outer level. We give computational results for a test set of 3- to 6-dimensional integrals, where several problems exhibit a loop integral behavior.

  9. A radial distribution function-based open boundary force model for multi-centered molecules

    KAUST Repository

    Neumann, Philipp

    2014-06-01

    We derive an expression for radial distribution function (RDF)-based open boundary forcing for molecules with multiple interaction sites. Due to the high-dimensionality of the molecule configuration space and missing rotational invariance, a computationally cheap, 1D approximation of the arising integral expressions as in the single-centered case is not possible anymore. We propose a simple, yet accurate model invoking standard molecule- and site-based RDFs to approximate the respective integral equation. The new open boundary force model is validated for ethane in different scenarios and shows very good agreement with data from periodic simulations. © World Scientific Publishing Company.

  10. Biomechanical comparison of force levels in spinal instrumentation using monoaxial versus multi degree of freedom postloading pedicle screws.

    Science.gov (United States)

    Wang, Xiaoyu; Aubin, Carl-Eric; Crandall, Dennis; Labelle, Hubert

    2011-01-15

    biomechanical analysis and simulations of correction mechanisms and force levels during scoliosis instrumentation using two types of pedicle screws and primary correction maneuvers. to biomechanically analyze implant-vertebra and inter-vertebral forces during scoliosis correction, to address the hypothesis that multi degree of freedom (MDOF) postloading screws with a direct incremental segmental translation (DIST) correction technique significantly reduce the loads as compared with monoaxial (MA) tulip-top design screws with a rod derotation technique (RDT). MA screw is widely used for spinal instrumentation. The MDOF screw was introduced as a refinement of the correction philosophy based on multiaxial screws. The kinematics of the MDOF construct is fundamentally different and offers more degrees of freedom than that of the MA construct; however, a systematic comparison of their biomechanics has not been done so far. a biomechanical model was developed to simulate the instrumentation of six scoliotic patients, first with the MDOF screws and DIST. Then, the instrumentation with MA screws and RDT was simulated using the same cases. Thirty more simulations were done to study the force-level sensitivity to small implant placement variation. there was a small average difference of 7°, 5°, and 4° between the two simulated systems for the computed main thoracic Cobb angle, kyphosis, and apical axial rotation, respectively. On average, the mean, standard deviation (SD), and maximum values of the implant-vertebra forces for MDOF screws were 56%, 59%, and 59%, respectively, lower than those for the MA screws, while the intervertebral forces for the MDOF screws were 31%, 37%, and 36% lower, respectively. Under the same set of random small implant placement changes, the mean, SD, and maximum values of implant-vertebra force magnitude changes for MDOF screws were 93%, 92%, and 95%, respectively, lower than those for MA screws. with MDOF screws and DIST, it is possible for

  11. Multi-Stage Flotation for the Removal of Ash from Fine Graphite Using Mechanical and Centrifugal Forces

    Directory of Open Access Journals (Sweden)

    Xiangning Bu

    2018-01-01

    Full Text Available Graphite ore collected from Hunan province, south China was characterized by chemical analysis, X-ray diffraction, and optical microscopy. Rougher and multi-stage flotation tests using a mechanical flotation cell and a flotation column containing an additional centrifugal force field were carried out to promote its grade and economic value. In rougher flotation, both the mechanical flotation cell and flotation column reduced the ash content of the graphite ore from 15.43% to 10.8%, while the yield of the flotation column (91.41% was much higher than that of the mechanical flotation cell (50%. In the presence of hydrophobic graphite, the seriously entrained gangue restricted further improvement in the quality and economic value of the graphite ore. Therefore, multi-stage flotation circuits were employed to diminish this entrainment. Multi-stage flotation circuits using the two flotation devices further decreased the ash content of the graphite ore to ~8%, while the yield when using the flotation column was much higher than that obtained from the mechanical flotation cell employed. On the other hand, the ash removal efficiency of the flotation column was 3.82-fold higher than that observed for the mechanical flotation cell. The Cleaner 3 flotation circuit using the flotation column decreased the ash content in graphite from 15.43% to 7.97% with a yield of 77.53%.

  12. A ''Fifth Force'' search using a controlled local mass

    International Nuclear Information System (INIS)

    Nelson, P.; Graham, D.; Nelson, P.; Newman, R.

    1988-01-01

    We present a progress report on a search for composition dependence in the forces acting on lead and copper test masses on a torsion balance due to a copper or lead attracting mass. The attracting mass in this experiment is a ring of radius R positioned so that the torsion balance lies on its axis at a distance z = √3/2.R from the ring's center. The ring is moved periodically between symmetric positions on opposite sides of the balance. The resulting change in gravitational field experienced by the balance is spatially uniform to a very high degree: all derivatives of the change in field at the center of the balance vanish through third order. The problem of gravitational field gradients coupling to the balance is thus minimized. This experiment should provide useful limits on the strength of composition dependent anomalous forces, independent of their range (for ranges greater than about 50 cm), and independent of assumptions about surrounding topography. We describe the performance of a first version of the experiment using a 28 kg copper ring, and discuss plans for an experiment using a 300 kg lead ring. No results are reported

  13. Exoskeleton master controller with force-reflecting telepresence

    Science.gov (United States)

    Burke, James B.; Bartholet, Stephen J.; Nelson, David K.

    1992-01-01

    A thorough understanding of the requirements for successful master-slave robotic systems is becoming increasingly desirable. Such systems can aid in the accomplishment of tasks that are hazardous or inaccessible to humans. Although a history of use has proven master-slave systems to be viable, system requirements and the impact of specifications on the human factors side of system performance are not well known. In support of the next phase of teleoperation research being conducted at the Armstrong Research Laboratory, a force-reflecting, seven degree of freedom exoskeleton for master-slave teleoperation has been concepted, and is presently being developed. The exoskeleton has a unique kinematic structure that complements the structure of the human arm. It provides a natural means for teleoperating a dexterous, possibly redundant manipulator. It allows ease of use without operator fatigue and faithfully follows human arm and wrist motions. Reflected forces and moments are remotely transmitted to the operator hand grip using a cable transmission scheme. This paper presents the exoskeleton concept and development results to date. Conceptual design, hardware, algorithms, computer architecture, and software are covered.

  14. Multi-Joint Dynamics and the Development of Movement Control

    Directory of Open Access Journals (Sweden)

    E. Otten

    2005-01-01

    Full Text Available The movement control of articulated limbs in humans has been explained in terms of equilibrium points and moving equilibrium points or virtual trajectories. One hypothesis is that the nervous system controls multi-segment limbs by simply planning in terms of these equilibrium points and trajectories. The present paper describes a planar computer simulation of an articulated three-segment limb, controlled by pairs of muscles. The shape of the virtual trajectory is analyzed when the limb is required to make fast movements with endpoint movements along a straight line with bell-shaped velocity profiles. Apparently, the faster the movement, the more the virtual trajectory deviates from the real trajectory and becomes up to eight times longer. The complexity of the shape of the virtual trajectories and its length in these fast movements makes it unlikely that the nervous system plans using these trajectories. it seems simpler to set up the required bursts of muscle activation, coupled in the nervous system to the direction of movement, the s peed, and the place in workspace. Finally, it is argued that the two types of explanation do not contradict each other: when a relation is established in the nervous system between muscle activation and movements, equilibrium points and virtual trajectories are necessarily part of that relation.

  15. Optimal control in microgrid using multi-agent reinforcement learning.

    Science.gov (United States)

    Li, Fu-Dong; Wu, Min; He, Yong; Chen, Xin

    2012-11-01

    This paper presents an improved reinforcement learning method to minimize electricity costs on the premise of satisfying the power balance and generation limit of units in a microgrid with grid-connected mode. Firstly, the microgrid control requirements are analyzed and the objective function of optimal control for microgrid is proposed. Then, a state variable "Average Electricity Price Trend" which is used to express the most possible transitions of the system is developed so as to reduce the complexity and randomicity of the microgrid, and a multi-agent architecture including agents, state variables, action variables and reward function is formulated. Furthermore, dynamic hierarchical reinforcement learning, based on change rate of key state variable, is established to carry out optimal policy exploration. The analysis shows that the proposed method is beneficial to handle the problem of "curse of dimensionality" and speed up learning in the unknown large-scale world. Finally, the simulation results under JADE (Java Agent Development Framework) demonstrate the validity of the presented method in optimal control for a microgrid with grid-connected mode. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Multi-MHz micro-electro-mechanical sensors for atomic force microscopy

    International Nuclear Information System (INIS)

    Legrand, Bernard; Salvetat, Jean-Paul; Walter, Benjamin; Faucher, Marc; Théron, Didier; Aimé, Jean-Pierre

    2017-01-01

    Silicon ring-shaped micro-electro-mechanical resonators have been fabricated and used as probes for dynamic atomic force microscopy (AFM) experiments. They offer resotnance frequency above 10 MHz, which is notably greater than that of usual cantilevers and quartz-based AFM probes. On-chip electrical actuation and readout of the tip oscillation are obtained by means of built-in capacitive transducers. Displacement and force resolutions have been determined from noise analysis at 1.5 fm/√Hz and 0.4 pN/√Hz, respectively. Despite the high effective stiffness of the probes, the tip-surface interaction force is kept below 1 nN by using vibration amplitude significantly below 100 pm and setpoint close to the free vibration conditions. Imaging capabilities in amplitude- and frequency-modulation AFM modes have been demonstrated on block copolymer surfaces. Z-spectroscopy experiments revealed that the tip is vibrating in permanent contact with the viscoelastic material, with a pinned contact line. Results are compared to those obtained with commercial AFM cantilevers driven at large amplitudes (>10 nm). - Highlights: • Silicon MEMS resonators are used as AFM probes above 10 MHz. • Integrated capacitive transducers drive and sense sub-nanometer tip oscillation. • Force resolution is below 1 pN/√Hz. • Block copolymer surface is imaged using AM and FM AFM modes. • Probes are operated at small vibration amplitude in permanent viscoelastic contact.

  17. Multi-MHz micro-electro-mechanical sensors for atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Legrand, Bernard, E-mail: bernard.legrand@laas.fr [LAAS-CNRS, Université de Toulouse, CNRS, 7 avenue du colonel Roche, F-31400 Toulouse (France); Salvetat, Jean-Paul [CRPP, 115 avenue Schweitzer, F-33600 Pessac (France); Walter, Benjamin; Faucher, Marc; Théron, Didier [IEMN, avenue Henri Poincaré, F-59652 Villeneuve d’Ascq (France); Aimé, Jean-Pierre [CBMN, allée Geoffroy Saint Hilaire, Bât. B14, F-33600 Pessac (France)

    2017-04-15

    Silicon ring-shaped micro-electro-mechanical resonators have been fabricated and used as probes for dynamic atomic force microscopy (AFM) experiments. They offer resotnance frequency above 10 MHz, which is notably greater than that of usual cantilevers and quartz-based AFM probes. On-chip electrical actuation and readout of the tip oscillation are obtained by means of built-in capacitive transducers. Displacement and force resolutions have been determined from noise analysis at 1.5 fm/√Hz and 0.4 pN/√Hz, respectively. Despite the high effective stiffness of the probes, the tip-surface interaction force is kept below 1 nN by using vibration amplitude significantly below 100 pm and setpoint close to the free vibration conditions. Imaging capabilities in amplitude- and frequency-modulation AFM modes have been demonstrated on block copolymer surfaces. Z-spectroscopy experiments revealed that the tip is vibrating in permanent contact with the viscoelastic material, with a pinned contact line. Results are compared to those obtained with commercial AFM cantilevers driven at large amplitudes (>10 nm). - Highlights: • Silicon MEMS resonators are used as AFM probes above 10 MHz. • Integrated capacitive transducers drive and sense sub-nanometer tip oscillation. • Force resolution is below 1 pN/√Hz. • Block copolymer surface is imaged using AM and FM AFM modes. • Probes are operated at small vibration amplitude in permanent viscoelastic contact.

  18. Complimentary Force Allocation Control for a Dual-Mover Linear Switched Reluctance Machine

    Directory of Open Access Journals (Sweden)

    J. F. Pan

    2017-12-01

    Full Text Available This paper inspects the complementary force allocation control schemes for an integrated, dual-mover linear switched reluctance machine (LSRM. The performance of the total force is realized by the coordination of the two movers. First, the structure and characteristics of the LSRM are investigated. Then, a complimentary force allocation control scheme for the two movers is proposed. Next, three force allocation methods—constant proportion, constant proportion with a saturation interval and error compensation, and the variable proportion allocation strategies—are proposed and analyzed, respectively. Experimental results demonstrate that the complimentary force interaction between the two movers can effectively reduce the total amount of force ripples from each method. The results under the variable proportion method also show that dynamic error values falling into 0.044 mm and −0.04 mm under the unit ramp force reference can be achieved. With the sinusoidal force reference with an amplitude of 60 N and a frequency of 0.5 Hz, a dynamic force control precision of 0.062 N and 0.091 N can also be obtained.

  19. Experimental study on the control interaction force coefficient; Soju ryutairyoku kansho keisu ni kansuru jikkenteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Nakatake, K; Oda, K; Yoshitake, A; Fujita, K; Nakajima, A [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1996-04-10

    The interaction force induced to hull by steering is important for prediction of control performance of ships. The control interaction force coefficient dependent on the steering has been investigated through the rudder angle tests using three small model ships with a length of 2.5 m, i.e., mathematical type of ship, cargo type of ship, and tanker type of ship. The interaction forces acting on the hull, propeller, and rudder were determined by measuring the lateral force as well as the forward force of the hydrodynamic forces acting on the rudder. These forces were compared with the theoretically calculated values. Prior to the rudder angle tests, the self propulsion factor and the number of revolution of propeller were determined from the results of the open water tests, resistance tests, and self propulsion tests by the changing load method. The rudder angle tests were conducted under this number of revolution of propeller as a standard condition, and under those increasing and decreasing by 15%. Consequently, the interaction forces determined from the rudder angle tests agreed well with those determined from the other tests. When comparing the control hydrodynamic forces determined from the tests with those theoretically calculated, a similar trend was observed. Effectiveness of the theoretical model was confirmed. 4 refs., 14 figs., 3 tabs.

  20. An experimental and multi-objective optimization study of a forced draft cooling tower with different fills

    International Nuclear Information System (INIS)

    Singh, Kuljeet; Das, Ranjan

    2016-01-01

    Highlights: • Experimental and optimization study on forced draft cooling tower is done. • New correlations for splash, trickle and film type fills are proposed. • Multi-objective performance optimization study has been done using NSGA-II. • Weighted decision making criterion is proposed depending upon user priority. • Proposed generalized methodology can be implemented in industrial cooling towers. - Abstract: In the present study, a forced draft mechanical cooling tower has been experimentally investigated using trickle, film and splash fills. Various performance parameters such as range, tower characteristic ratio, effectiveness and water evaporation rate are first analyzed for each fill. Thereafter, based upon the experimental data, pertinent correlations have been developed for performance parameters by considering mass flow rates of water and air as design variables. Each of the performance parameters is considered to be an individual objective function and all objectives are then simultaneously optimized for maximizing the performance of the cooling tower using elitist Non-Dominated Sorting Genetic Algorithm (NSGA-II). The multi-objective optimization algorithm gives a set of possible combinations of design variables, which is referred as the optimal Pareto-front, out of which a unique combination is selected based upon a decision making criterion. The proposed decision making procedure evaluates a Decision Making Score (DMS) based on assigned performance priorities for each point of the Pareto-front. Depending on DMS a unique combination of design variables is then selected for each type of fill that maximizes the tower’s performance. These optimal points and the corresponding objective function are finally compared and based upon the highest DMS value, the wire-mesh (trickle) fill is found to be the most efficient fill under the present experimental conditions. The methodology presented in this work has been made more generalized, so that it

  1. Characterization and optimized control by means of multi-parameter controllers

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Carsten; Hoeg, S.; Thoegersen, A. (Dan-Ejendomme, Hellerup (Denmark)) (and others)

    2009-07-01

    Poorly functioning HVAC systems (Heating, Ventilation and Air Conditioning), but also separate heating, ventilation and air conditioning systems are costing the Danish society billions of kroner every year: partly because of increased energy consumption and high operational and maintenance costs, but mainly due to reduced productivity and absence due to illness because of a poor indoor climate. Typically, the operation of buildings and installations takes place today with traditional build-ing automation, which is characterised by 1) being based on static considerations 2) the individual sensor being coupled with one actuator/valve, i.e. the sensor's signal is only used in one place in the system 3) subsystems often being controlled independently of each other 4) the dynamics in building constructions and systems which is very important to the system and comfort regulation is not being considered. This, coupled with the widespread tendency to use large glass areas in the facades without sufficient sun shading, means that it is difficult to optimise comfort and energy consumption. Therefore, the last 10-20 years have seen a steady increase in the complaints of the indoor climate in Danish buildings and, at the same time, new buildings often turn out to be considerably higher energy consuming than expected. The purpose of the present project is to investigate the type of multi parameter sensors which may be generated for buildings and further to carry out a preliminary evaluation on how such multi parameter controllers may be utilized for optimal control of buildings. The aim of the project isn't to develop multi parameter controllers - this requires much more effort than possible in the present project. The aim is to show the potential of using multi parameter sensors when controlling buildings. For this purpose a larger office building has been chosen - an office building with at high energy demand and complaints regarding the indoor climate. In order to

  2. 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

  3. A computed torque method based attitude control with optimal force distribution for articulated body mobile robots

    International Nuclear Information System (INIS)

    Fukushima, Edwardo F.; Hirose, Shigeo

    2000-01-01

    This paper introduces an attitude control scheme based in optimal force distribution using quadratic programming which minimizes joint energy consumption. This method shares similarities with force distribution for multifingered hands, multiple coordinated manipulators and legged walking robots. In particular, an attitude control scheme was introduced inside the force distribution problem, and successfully implemented for control of the articulated body mobile robot KR-II. This is an actual mobile robot composed of cylindrical segments linked in series by prismatic joints and has a long snake-like appearance. These prismatic joints are force controlled so that each segment's vertical motion can automatically follow the terrain irregularities. An attitude control is necessary because this system acts like a system of wheeled inverted pendulum carts connected in series, being unstable by nature. The validity and effectiveness of the proposed method is verified by computer simulation and experiments with the robot KR-II. (author)

  4. 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.

  5. Force control of a magnetorheological damper using an elementary hysteresis model-based feedforward neural network

    International Nuclear Information System (INIS)

    Ekkachai, Kittipong; Nilkhamhang, Itthisek; Tungpimolrut, Kanokvate

    2013-01-01

    An inverse controller is proposed for a magnetorheological (MR) damper that consists of a hysteresis model and a voltage controller. The force characteristics of the MR damper caused by excitation signals are represented by a feedforward neural network (FNN) with an elementary hysteresis model (EHM). The voltage controller is constructed using another FNN to calculate a suitable input signal that will allow the MR damper to produce the desired damping force. The performance of the proposed EHM-based FNN controller is experimentally compared to existing control methodologies, such as clipped-optimal control, signum function control, conventional FNN, and recurrent neural network with displacement or velocity inputs. The results show that the proposed controller, which does not require force feedback to implement, provides excellent accuracy, fast response time, and lower energy consumption. (paper)

  6. Linear and Non-linear Multi-Input Multi-Output Model Predictive Control of Continuous Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    Muayad Al-Qaisy

    2015-02-01

    Full Text Available In this article, multi-input multi-output (MIMO linear model predictive controller (LMPC based on state space model and nonlinear model predictive controller based on neural network (NNMPC are applied on a continuous stirred tank reactor (CSTR. The idea is to have a good control system that will be able to give optimal performance, reject high load disturbance, and track set point change. In order to study the performance of the two model predictive controllers, MIMO Proportional-Integral-Derivative controller (PID strategy is used as benchmark. The LMPC, NNMPC, and PID strategies are used for controlling the residual concentration (CA and reactor temperature (T. NNMPC control shows a superior performance over the LMPC and PID controllers by presenting a smaller overshoot and shorter settling time.

  7. Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

    Directory of Open Access Journals (Sweden)

    Lihang Feng

    Full Text Available Wheel force transducer (WFT, which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

  8. Inertia coupling analysis of a self-decoupled wheel force transducer under multi-axis acceleration fields.

    Science.gov (United States)

    Feng, Lihang; Lin, Guoyu; Zhang, Weigong; Dai, Dong

    2015-01-01

    Wheel force transducer (WFT), which measures the three-axis forces and three-axis torques applied to the wheel, is an important instrument in the vehicle testing field and has been extremely promoted by researchers with great interests. The transducer, however, is typically mounted on the wheel of a moving vehicle, especially on a high speed car, when abruptly accelerating or braking, the mass/inertia of the transducer/wheel itself will have an extra effect on the sensor response so that the inertia/mass loads will also be detected and coupled into the signal outputs. The effect which is considered to be inertia coupling problem will decrease the sensor accuracy. In this paper, the inertia coupling of a universal WFT under multi-axis accelerations is investigated. According to the self-decoupling approach of the WFT, inertia load distribution is solved based on the principle of equivalent mass and rotary inertia, thus then inertia impact can be identified with the theoretical derivation. The verification is achieved by FEM simulation and experimental tests. Results show that strains in simulation agree well with the theoretical derivation. The relationship between the applied acceleration and inertia load for both wheel force and moment is the approximate linear, respectively. All the relative errors are less than 5% which are within acceptable and the inertia loads have the maximum impact on the signal output about 1.5% in the measurement range.

  9. Identification and Modeling of Electrohydraulic Force Control of the Material Test System (MTS)

    International Nuclear Information System (INIS)

    Ruan, J; Pei, X; Zhu, F M

    2006-01-01

    In the heavy-duty material test device, an electrohydraulic force servo system is usually utilized to load the tested samples. The signal from the pressure sensor is compared with the instruction and the difference between them is then fed to a digital servo valve to form a closed loop control to the target force. The performance of the electrohydraulic force servo system is not only closely related to how accurate to feed the flow rate to the hydraulic cylinder, but also the stiffness of the system which is dominated by the compressibility of oil. Thus the clarification of the characteristic parameters becomes the key of the solution to optimal force control. To identify the electrohydraulic force servo system various step signals are input to excite the dynamic response of the system. From the relationship between the step magnitude and the force response, the system model and the key control parameters are determined. The electrohydraulic force servo system is identified as a first order system with time constant varied with the pressure. Based on the identification of the system optimal control parameters are finally obtained and force rate error is reduced to 0.2% from original 3%

  10. Force control in the absence of visual and tactile feedback

    NARCIS (Netherlands)

    Mugge, W.; Abbink, D.A.; Schouten, Alfred Christiaan; van der Helm, F.C.T.; Arendzen, J.H.; Meskers, C.G.M.

    2013-01-01

    Motor control tasks like stance or object handling require sensory feedback from proprioception, vision and touch. The distinction between tactile and proprioceptive sensors is not frequently made in dynamic motor control tasks, and if so, mostly based on signal latency. We previously found that

  11. 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.

  12. A design method of compensators for multi-variable control system with PID controllers 'CHARLY'

    International Nuclear Information System (INIS)

    Fujiwara, Toshitaka; Yamada, Katsumi

    1985-01-01

    A systematic design method of compensators for a multi-variable control system having usual PID controllers in its loops is presented in this paper. The method itself is able: to determine the main manipulating variable corresponding to each controlled variable with a sensitivity analysis in the frequency domain. to tune PID controllers sufficiently to realize adequate control actions with a searching technique of minimum values of cost functionals. to design compensators improving the control preformance and to simulate a total system for confirming the designed compensators. In the phase of compensator design, the state variable feed-back gain is obtained by means of the OPTIMAL REGULATOR THEORY for the composite system of plant and PID controllers. The transfer function type compensators the configurations of which were previously given are, then, designed to approximate the frequency responces of the above mentioned state feed-back system. An example is illustrated for convenience. (author)

  13. Dynamical signatures of isometric force control as a function of age, expertise, and task constraints.

    Science.gov (United States)

    Vieluf, Solveig; Sleimen-Malkoun, Rita; Voelcker-Rehage, Claudia; Jirsa, Viktor; Reuter, Eva-Maria; Godde, Ben; Temprado, Jean-Jacques; Huys, Raoul

    2017-07-01

    From the conceptual and methodological framework of the dynamical systems approach, force control results from complex interactions of various subsystems yielding observable behavioral fluctuations, which comprise both deterministic (predictable) and stochastic (noise-like) dynamical components. Here, we investigated these components contributing to the observed variability in force control in groups of participants differing in age and expertise level. To this aim, young (18-25 yr) as well as late middle-aged (55-65 yr) novices and experts (precision mechanics) performed a force maintenance and a force modulation task. Results showed that whereas the amplitude of force variability did not differ across groups in the maintenance tasks, in the modulation task it was higher for late middle-aged novices than for experts and higher for both these groups than for young participants. Within both tasks and for all groups, stochastic fluctuations were lowest where the deterministic influence was smallest. However, although all groups showed similar dynamics underlying force control in the maintenance task, a group effect was found for deterministic and stochastic fluctuations in the modulation task. The latter findings imply that both components were involved in the observed group differences in the variability of force fluctuations in the modulation task. These findings suggest that between groups the general characteristics of the dynamics do not differ in either task and that force control is more affected by age than by expertise. However, expertise seems to counteract some of the age effects. NEW & NOTEWORTHY Stochastic and deterministic dynamical components contribute to force production. Dynamical signatures differ between force maintenance and cyclic force modulation tasks but hardly between age and expertise groups. Differences in both stochastic and deterministic components are associated with group differences in behavioral variability, and observed behavioral

  14. Automatic analysis of force distribution in multi-fingered articulated hands

    Science.gov (United States)

    Amani, Mahyar

    A kinematic and force analysis of multifingered, multijointed dexterous hands is presented. The analysis involves calculation of the basis for null space of the grasp matrix. An algorithm is developed to perform all necessary analyses of dexterous hands. All equality and inequality constraints are automatically formulated in a constraint matrix. These include unisense constraints, frictional constraints, and joint torque limits. The reduction of the constraint matrix into a compact form is also presented. The algorithm is written in Fortran and is user-friendly and capable of handling all practical grasping problems. Different types of contact may be examined, including soft finger contact and point contact with and without friction. The software can easily determine the feasibility of a grasp for a given set of contact forces/torques, and may potentially be combined with either routines to compute the optimum value of contact wrench intensities and joint torque values.

  15. Interaction forces and conduction properties between multi wall carbon nanotube tips and Au(1 1 1)

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Pablo, P.J. de; Colchero, J.; Gomez-Herrero, J.; Baro, A.M.; Tokumoto, H.; Jarvis, S.P

    2003-07-15

    We have studied the interaction forces and electrical conduction properties arising between multiwall carbon nanotube tips and the Au(1 1 1) surface in air, by means of amplitude modulation scanning force microscopy, also called intermittent contact. We have centered our work on tips with metallic electronic structure and for the specific parameters used we have found a preliminary interaction range where there is no contact between tip and surface. Stable imaging in this non-contact range is possible with multiwall carbon nanotube tips. These tips have also been used to obtain simultaneous topographic and current maps of the surface. They show excellent properties as tips due to their high aspect ratio and durability, as a result of their elastic and non-reactive properties. Correspondingly, multiwall carbon nanotube tips allow high resolution local analysis of electrical conductivity on a nanometer scale.

  16. Prediction of forces and moments for flight vehicle control effectors. Part 1: Validation of methods for predicting hypersonic vehicle controls forces and moments

    Science.gov (United States)

    Maughmer, Mark D.; Ozoroski, L.; Ozoroski, T.; Straussfogel, D.

    1990-01-01

    Many types of hypersonic aircraft configurations are currently being studied for feasibility of future development. Since the control of the hypersonic configurations throughout the speed range has a major impact on acceptable designs, it must be considered in the conceptual design stage. The ability of the aerodynamic analysis methods contained in an industry standard conceptual design system, APAS II, to estimate the forces and moments generated through control surface deflections from low subsonic to high hypersonic speeds is considered. Predicted control forces and moments generated by various control effectors are compared with previously published wind tunnel and flight test data for three configurations: the North American X-15, the Space Shuttle Orbiter, and a hypersonic research airplane concept. Qualitative summaries of the results are given for each longitudinal force and moment and each control derivative in the various speed ranges. Results show that all predictions of longitudinal stability and control derivatives are acceptable for use at the conceptual design stage. Results for most lateral/directional control derivatives are acceptable for conceptual design purposes; however, predictions at supersonic Mach numbers for the change in yawing moment due to aileron deflection and the change in rolling moment due to rudder deflection are found to be unacceptable. Including shielding effects in the analysis is shown to have little effect on lift and pitching moment predictions while improving drag predictions.

  17. Transmit Antenna Selection for Multi-User Underlay Cognitive Transmission with Zero-Forcing Beamforming

    KAUST Repository

    Hanif, Muhammad

    2017-03-20

    We present a transmit antenna subset selection scheme for an underlay cognitive system serving multiple secondary receivers. The secondary system employs zero-forcing beamforming to nullify the interference to multiple primary users and eliminate inter-user interference to the secondary users simultaneously. Simulation results show that the proposed scheme achieves near-optimal performance with low computational complexity. Lastly, an optimal power allocation strategy is also introduced to improve the secondary network throughput.

  18. Hybrid Force Control Based on ICMAC for an Astronaut Rehabilitative Training Robot

    Directory of Open Access Journals (Sweden)

    Lixun Zhang

    2012-08-01

    Full Text Available A novel Astronaut Rehabilitative Training Robot (ART based on a cable-driven mechanism is represented in this paper. ART, a typical passive force servo system, can help astronauts to bench press in a microgravity environment. The purpose of this paper is to design controllers to eliminate the surplus force caused by an astronaut's active movements. Based on the dynamics modelling of the cable-driven unit, a hybrid force controller based on improved credit assignment CMAC (ICMAC is presented. A planning method for the cable tension is proposed so that the dynamic load produced by the ART can realistically simulate the gravity and inertial force of the barbell in a gravity environment. Finally, MATLAB simulation results of the man-machine cooperation system are provided in order to verify the effectiveness of the proposed control strategy. The simulation results show that the hybrid control method based on the structure invariance principle can inhibit the surplus force and that ICMAC can improve the dynamic performance of the passive force servo system. Furthermore, the hybrid force controller based on ICMAC can ensure the stability of the system.

  19. Multi-function magnetic jack control drive mechanism

    International Nuclear Information System (INIS)

    Bollinger, L.R.; Crawford, D.C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism is described for controlling a nuclear reactor comprising: an elongate pressure housing; closely-spaced drive rods located in the pressure housing, the drive rod being connected to a reactor rod which is insertable in a reactor core; electrochemical stationary latch means which are selectively actuatable for holding a respective one of the drive rods stationary with respect to the pressure housing, the plurality of stationary latch means including at least one coil located about the pressure housing; longitudinally spaced electromechanical movable latch means, individually associated with one of the drive rods and each including a base for the drive rod associated therewith, for, when actuated, holding the associated drive rod stationary with respect to the base associated therewith, the movable latch means including an associated coil located about the pressure housing; and longitudinally spaced electromechanical lift means, individually associated with the base, for, when actuated, moving an associated base longitudinally along the pressure housing from a first position to a second position to thereby enable movement of one or more of the other drive rods longitudinally independently of the other drive rods in response to sequential and repeated operation of the electromechanical means, the lift means including an associated coil located about the pressure housing

  20. Decentralized control of multi-agent aerial transportation system

    KAUST Repository

    Toumi, Noureddine

    2017-04-01

    Autonomous aerial transportation has multiple potential applications including emergency cases and rescue missions where ground intervention may be difficult. In this context, the following work will address the control of multi-agent Vertical Take-off and Landing aircraft (VTOL) transportation system. We develop a decentralized method. The advantage of such a solution is that it can provide better maneuverability and lifting capabilities compared to existing systems. First, we consider a cooperative group of VTOLs transporting one payload. The main idea is that each agent perceive the interaction with other agents as a disturbance while assuming a negotiated motion model and imposing certain magnitude bounds on each agent. The theoretical model will be then validated using a numerical simulation illustrating the interesting features of the presented control method. Results show that under specified disturbances, the algorithm is able to guarantee the tracking with a minimal error. We describe a toolbox that has been developed for this purpose. Then, a system of multiple VTOLs lifting payloads will be studied. The algorithm assures that the VTOLs are coordinated with minimal communication. Additionally, a novel gripper design for ferrous objects is presented that enables the transportation of ferrous objects without a cable. Finally, we discuss potential connections to human in the loop transportation systems.

  1. Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation.

    Science.gov (United States)

    Fu, Qiushi; Zhang, Wei; Santello, Marco

    2010-07-07

    Dexterous object manipulation requires anticipatory control of digit positions and forces. Despite extensive studies on sensorimotor learning of digit forces, how humans learn to coordinate digit positions and forces has never been addressed. Furthermore, the functional role of anticipatory modulation of digit placement to object properties remains to be investigated. We addressed these questions by asking human subjects (12 females, 12 males) to grasp and lift an inverted T-shaped object using precision grip at constrained or self-chosen locations. The task requirement was to minimize object roll during lift. When digit position was not constrained, subjects could have implemented many equally valid digit position-force coordination patterns. However, choice of digit placement might also have resulted in large trial-to-trial variability of digit position, hence challenging the extent to which the CNS could have relied on sensorimotor memories for anticipatory control of digit forces. We hypothesized that subjects would modulate digit placement for optimal force distribution and digit forces as a function of variable digit positions. All subjects learned to minimize object roll within the first three trials, and the unconstrained device was associated with significantly smaller grip forces but larger variability of digit positions. Importantly, however, digit load force modulation compensated for position variability, thus ensuring consistent object roll minimization on each trial. This indicates that subjects learned object manipulation by integrating sensorimotor memories with sensory feedback about digit positions. These results are discussed in the context of motor equivalence and sensorimotor integration of grasp kinematics and kinetics.

  2. Reform of Command and Control Structures in North Atlantic Treaty Organization Special Operations Forces

    National Research Council Canada - National Science Library

    Berg, Robert S

    2007-01-01

    .... The central research question is as follows: Does NATO require a standing Special Operations Force Command and Control structure and combat capability to meet the emerging global security requirements of the Alliance...

  3. Centralized Command and Control of Theater Missile Defense: The Joint Force Missile Defense Component Coordinator

    National Research Council Canada - National Science Library

    Bucey, William H

    2006-01-01

    .... The numerous commands, decentralized command and control, and limited and expensive resources involved in TMD require changes to the joint doctrine in order to provide unity of command and economy of force...

  4. Vehicle Sliding Mode Control with Adaptive Upper Bounds: Static versus Dynamic Allocation to Saturated Tire Forces

    Directory of Open Access Journals (Sweden)

    Ali Tavasoli

    2012-01-01

    Full Text Available Nonlinear vehicle control allocation is achieved through distributing the task of vehicle control among individual tire forces, which are constrained to nonlinear saturation conditions. A high-level sliding mode control with adaptive upper bounds is considered to assess the body yaw moment and lateral force for the vehicle motion. The proposed controller only requires the online adaptation of control gains without acquiring the knowledge of upper bounds on system uncertainties. Static and dynamic control allocation approaches have been formulated to distribute high-level control objectives among the system inputs. For static control allocation, the interior-point method is applied to solve the formulated nonlinear optimization problem. Based on the dynamic control allocation method, a dynamic update law is derived to allocate vehicle control to tire forces. The allocated tire forces are fed into a low-level control module, where the applied torque and active steering angle at each wheel are determined through a slip-ratio controller and an inverse tire model. Computer simulations are used to prove the significant effects of the proposed control allocation methods on improving the stability and handling performance. The advantages and limitations of each method have been discussed, and conclusions have been derived.

  5. Consequences of Inconsistency in Air Force Tobacco Control Policy.

    Science.gov (United States)

    Lando-King, Elizabeth A; Malone, Ruth E; Haddock, Christopher K; Poston, Walker S Carlos; Lando, Harry A; Jahnke, Sara A; Hawk, Nita; Smith, Elizabeth A

    2017-04-01

    Although the United States Air Force (USAF) has been a leader in efforts to reduce tobacco use among service members, tobacco continues to be a problem and initiatives to decrease tobacco use further require buy-in from leadership. We explored line leaderships' perspectives on tobacco. A diverse group of 10 senior commissioned and 10 non-commissioned personnel were interviewed. Respondents reported substantial changes in the culture of tobacco use during their years of service, from near ubiquity to restricted use areas. They also perceived mixed messages coming from the USAF, including simultaneous discouragement of and accommodations for tobacco use, and variability in policies and enforcement. Many respondents indicated that allowing tobacco use creates conflict and undermines military discipline and suggested that a tobacco-free policy would be the best way to eliminate these contradictions. Although there has been substantial movement away from a culture of tobacco in the USAF, current policies and variable enforcement of these policies create unnecessary contradictions. Establishing a tobacco-free service would resolve these issues in addition to improving the health of service members and veterans.

  6. Vehicle Dynamics Control of In-wheel Electric Motor Drive Vehicles Based on Averaging of Tire Force Usage

    Science.gov (United States)

    Masaki, Nobuo; Iwano, Haruo; Kamada, Takayoshi; Nagai, Masao

    For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

  7. Delay-based virtual congestion control in multi-tenant datacenters

    Science.gov (United States)

    Liu, Yuxin; Zhu, Danhong; Zhang, Dong

    2018-03-01

    With the evolution of cloud computing and virtualization, the congestion control of virtual datacenters has become the basic issue for multi-tenant datacenters transmission. Regarding to the friendly conflict of heterogeneous congestion control among multi-tenant, this paper proposes a delay-based virtual congestion control, which translates the multi-tenant heterogeneous congestion control into delay-based feedback uniformly by setting the hypervisor translation layer, modifying three-way handshake of explicit feedback and packet loss feedback and throttling receive window. The simulation results show that the delay-based virtual congestion control can effectively solve the unfairness of heterogeneous feedback congestion control algorithms.

  8. A multi-channel humidity control system based on LabVIEW

    International Nuclear Information System (INIS)

    Zhang Aiwu; Xie Yuguang; Liu Hongbang; Liu Yingbiao; Cai Xiao; Yu Boxiang; Lu Junguang; Zhou Li

    2011-01-01

    A real time multi-channel humidity control system was designed based on LabVIEW, using the dry air branch of BESⅢ drying system. The hardware of this control system consist of mini humidity and temperature sensors, intelligent collection module, switch quantity controller and electromagnetic valves. The humidity can be controlled at arbitrary value from air humidity to 3% with accuracy better than 2%. Multi microenvironment with different humidity can be easily controlled and monitored in real time by this system. It can also be extended to hybrid control of multi channel humidity and temperature. (authors)

  9. Composite adaptive control of belt polishing force for aero-engine blade

    Science.gov (United States)

    Zhsao, Pengbing; Shi, Yaoyao

    2013-09-01

    The existing methods for blade polishing mainly focus on robot polishing and manual grinding. Due to the difficulty in high-precision control of the polishing force, the blade surface precision is very low in robot polishing, in particular, quality of the inlet and exhaust edges can not satisfy the processing requirements. Manual grinding has low efficiency, high labor intensity and unstable processing quality, moreover, the polished surface is vulnerable to burn, and the surface precision and integrity are difficult to ensure. In order to further improve the profile accuracy and surface quality, a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed, which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together. By the mode decision-making mechanism, Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value, and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision. Based on the mathematical model of the force-exerting mechanism, simulation analysis is implemented on DSCAC. Simulation results show that the output polishing force can better track the given signal. Finally, the blade polishing experiments are carried out on the designed polishing equipment. Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility, valve dead-time effect, valve nonlinear flow, cylinder friction, measurement noise and other interference on the control precision of polishing force, which has high control precision, strong robustness, strong anti-interference ability and other advantages compared with MRACFNN. The proposed research achieves high-precision control of the polishing force, effectively improves the blade machining precision and surface consistency, and

  10. Deficits of anticipatory grip force control after damage to peripheral and central sensorimotor systems.

    Science.gov (United States)

    Hermsdörfer, Joachim; Hagl, Elke; Nowak, Dennis A

    2004-11-01

    Healthy subjects adjust their grip force economically to the weight of a hand-held object. In addition, inertial loads, which arise from arm movements with the grasped object, are anticipated by parallel grip force modulations. Internal forward models have been proposed to predict the consequences of voluntary movements. Anesthesia of the fingers impairs grip force economy but the feedforward character of the grip force/load coupling is preserved. To further analyze the role of sensory input for internal forward models and to characterize the consequences of central nervous system damage for anticipatory grip force control, we measured grip force behavior in neurological patients. We tested a group of stroke patients with varying degrees of impaired fine motor control and sensory loss, a single patient with complete and permanent differentation from all tactile and proprioceptive input, and a group of patients with amyotrophic lateral sclerosis (ALS) that exclusively impairs the motor system without affecting sensory modalities. Increased grip forces were a common finding in all patients. Sensory deficits were a strong but not the only predictor of impaired grip force economy. The feedforward mode of grip force control was typically preserved in the stroke patients despite their central sensory deficits, but was severely disturbed in the patient with peripheral sensory deafferentation and in a minority of stroke patients. Moderate deficits of feedforward control were also obvious in ALS patients. Thus, the function of the internal forward model and the precision of grip force production may depend on a complex anatomical and functional network of sensory and motor structures and their interaction in time and space.

  11. A study of pilot modeling in multi-controller tasks

    Science.gov (United States)

    Whitbeck, R. F.; Knight, J. R.

    1972-01-01

    A modeling approach, which utilizes a matrix of transfer functions to describe the human pilot in multiple input, multiple output control situations, is studied. The approach used was to extend a well established scalar Wiener-Hopf minimization technique to the matrix case and then study, via a series of experiments, the data requirements when only finite record lengths are available. One of these experiments was a two-controller roll tracking experiment designed to force the pilot to use rudder in order to coordinate and reduce the effects of aileron yaw. One model was computed for the case where the signals used to generate the spectral matrix are error and bank angle while another model was computed for the case where error and yaw angle are the inputs. Several anomalies were observed to be present in the experimental data. These are defined by the descriptive terms roll up, break up, and roll down. Due to these algorithm induced anomalies, the frequency band over which reliable estimates of power spectra can be achieved is considerably less than predicted by the sampling theorem.

  12. 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.

  13. Optimizing Multi-Product Multi-Constraint Inventory Control Systems with Stochastic Replenishments

    Science.gov (United States)

    Allah Taleizadeh, Ata; Aryanezhad, Mir-Bahador; Niaki, Seyed Taghi Akhavan

    Multi-periodic inventory control problems are mainly studied employing two assumptions. The first is the continuous review, where depending on the inventory level orders can happen at any time and the other is the periodic review, where orders can only happen at the beginning of each period. In this study, we relax these assumptions and assume that the periodic replenishments are stochastic in nature. Furthermore, we assume that the periods between two replenishments are independent and identically random variables. For the problem at hand, the decision variables are of integer-type and there are two kinds of space and service level constraints for each product. We develop a model of the problem in which a combination of back-order and lost-sales are considered for the shortages. Then, we show that the model is of an integer-nonlinear-programming type and in order to solve it, a search algorithm can be utilized. We employ a simulated annealing approach and provide a numerical example to demonstrate the applicability of the proposed methodology.

  14. Experimental study of tube/support impact forces in multi-span PWR steam generator tubes

    International Nuclear Information System (INIS)

    Axisa, F.; Desseaux, A.; Gibert, R.J.

    1984-12-01

    The vibro-impact response of a straight part of a steam generator tube is investigated experimentally and using numerical simulation with the aim to relate tube overall dynamics with excitation and tube-support clearance. Configuration studied here corresponds to the tube being excited in only one direction at its first resonance presenting an antinode of vibration at the impacted support. Tests show namely that midspan displacement of tube is almost proportional to excitation level and clearance. Impact forces averaged over a cycle of vibration are almost proportional to excitation and poorly dependent on clearance. Results of numerical simulation are in fairly good agreement with test results

  15. Dicyclopentadiene Hydrogenation in Trickle Bed Reactor under Forced Periodic Control

    Czech Academy of Sciences Publication Activity Database

    Skála, D.; Hanika, Jiří

    2008-01-01

    Roč. 62, č. 2 (2008), s. 215-218 ISSN 1336-7242 R&D Projects: GA MPO(CZ) FT-TA/039 Institutional research plan: CEZ:AV0Z40720504 Keywords : periodic control * trickle -bed reactor * dicyclopentadiene Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  16. Multi-morbidities of allergic rhinitis in adults: European Academy of Allergy and Clinical Immunology Task Force Report.

    Science.gov (United States)

    Cingi, C; Gevaert, P; Mösges, R; Rondon, C; Hox, V; Rudenko, M; Muluk, N B; Scadding, G; Manole, F; Hupin, C; Fokkens, W J; Akdis, C; Bachert, C; Demoly, P; Mullol, J; Muraro, A; Papadopoulos, N; Pawankar, R; Rombaux, P; Toskala, E; Kalogjera, L; Prokopakis, E; Hellings, P W; Bousquet, J

    2017-01-01

    This report has been prepared by the European Academy of Allergy and Clinical Immunology Task Force on Allergic Rhinitis (AR) comorbidities. The aim of this multidisciplinary European consensus document is to highlight the role of multimorbidities in the definition, classification, mechanisms, recommendations for diagnosis and treatment of AR, and to define the needs in this neglected area by a literature review. AR is a systemic allergic disease and is generally associated with numerous multi-morbid disorders, including asthma, eczema, food allergies, eosinophilic oesophagitis (EoE), conjunctivitis, chronic middle ear effusions, rhinosinusitis, adenoid hypertrophy, olfaction disorders, obstructive sleep apnea, disordered sleep and consequent behavioural and educational effects. This report provides up-to-date usable information to: (1) improve the knowledge and skills of allergists, so as to ultimately improve the overall quality of patient care; (2) to increase interest in this area; and (3) to present a unique contribution to the field of upper inflammatory disease.

  17. Development of Constraint Force Equation Methodology for Application to Multi-Body Dynamics Including Launch Vehicle Stage Seperation

    Science.gov (United States)

    Pamadi, Bandu N.; Toniolo, Matthew D.; Tartabini, Paul V.; Roithmayr, Carlos M.; Albertson, Cindy W.; Karlgaard, Christopher D.

    2016-01-01

    The objective of this report is to develop and implement a physics based method for analysis and simulation of multi-body dynamics including launch vehicle stage separation. The constraint force equation (CFE) methodology discussed in this report provides such a framework for modeling constraint forces and moments acting at joints when the vehicles are still connected. Several stand-alone test cases involving various types of joints were developed to validate the CFE methodology. The results were compared with ADAMS(Registered Trademark) and Autolev, two different industry standard benchmark codes for multi-body dynamic analysis and simulations. However, these two codes are not designed for aerospace flight trajectory simulations. After this validation exercise, the CFE algorithm was implemented in Program to Optimize Simulated Trajectories II (POST2) to provide a capability to simulate end-to-end trajectories of launch vehicles including stage separation. The POST2/CFE methodology was applied to the STS-1 Space Shuttle solid rocket booster (SRB) separation and Hyper-X Research Vehicle (HXRV) separation from the Pegasus booster as a further test and validation for its application to launch vehicle stage separation problems. Finally, to demonstrate end-to-end simulation capability, POST2/CFE was applied to the ascent, orbit insertion, and booster return of a reusable two-stage-to-orbit (TSTO) vehicle concept. With these validation exercises, POST2/CFE software can be used for performing conceptual level end-to-end simulations, including launch vehicle stage separation, for problems similar to those discussed in this report.

  18. Visually and force controlled opening and closing of doors by means of a mobile robot arm

    OpenAIRE

    Milighetti, G.; Hoffmann, E.; Fetzner, Angelika; Kuntze, Helge-Björn

    2012-01-01

    A multi-sensory discrete-continuous control concept has been developed to realize interactive basic skills for humanoid and mobile service robots. In the upper hierarchy level a discrete task control structure enables the flexible execution of primitive skill sequences. In the lower continuous level a suitable controller is chosen with control parameters adapted to the current primitive skill. The basic skill for the frequently occurring task of unlocking and opening a door by means of a mobi...

  19. Fitts’ Law in the Control of Isometric Grip Force With Naturalistic Targets

    Directory of Open Access Journals (Sweden)

    Zachary C. Thumser

    2018-04-01

    Full Text Available Fitts’ law models the relationship between amplitude, precision, and speed of rapid movements. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Applying Fitts’ law to an isometric grip force task would allow for quantifying grasp performance in rehabilitative medicine and may aid research on prosthetic control and design. We examined whether Fitts’ law would hold when participants attempted to accurately produce their intended force output while grasping a manipulandum when presented with images of various everyday objects (we termed this the implicit task. Although our main interest was the implicit task, to benchmark it and establish validity, we examined performance against a more standard visual feedback condition via a digital force-feedback meter on a video monitor (explicit task. Next, we progressed from visual force feedback with force meter targets to the same targets without visual force feedback (operating largely on feedforward control with tactile feedback. This provided an opportunity to see if Fitts’ law would hold without vision, and allowed us to progress toward the more naturalistic implicit task (which does not include visual feedback. Finally, we changed the nature of the targets from requiring explicit force values presented as arrows on a force-feedback meter (explicit targets to the more naturalistic and intuitive target forces implied by images of objects (implicit targets. With visual force feedback the relation between task difficulty and the time to produce the target grip force was predicted by Fitts’ law (average r2 = 0.82. Without vision, average grip force scaled accurately although force variability was insensitive to the target presented. In contrast, images of everyday objects generated more reliable grip forces

  20. Fitts' Law in the Control of Isometric Grip Force With Naturalistic Targets.

    Science.gov (United States)

    Thumser, Zachary C; Slifkin, Andrew B; Beckler, Dylan T; Marasco, Paul D

    2018-01-01

    Fitts' law models the relationship between amplitude, precision, and speed of rapid movements. It is widely used to quantify performance in pointing tasks, study human-computer interaction, and generally to understand perceptual-motor information processes, including research to model performance in isometric force production tasks. Applying Fitts' law to an isometric grip force task would allow for quantifying grasp performance in rehabilitative medicine and may aid research on prosthetic control and design. We examined whether Fitts' law would hold when participants attempted to accurately produce their intended force output while grasping a manipulandum when presented with images of various everyday objects (we termed this the implicit task). Although our main interest was the implicit task, to benchmark it and establish validity, we examined performance against a more standard visual feedback condition via a digital force-feedback meter on a video monitor (explicit task). Next, we progressed from visual force feedback with force meter targets to the same targets without visual force feedback (operating largely on feedforward control with tactile feedback). This provided an opportunity to see if Fitts' law would hold without vision, and allowed us to progress toward the more naturalistic implicit task (which does not include visual feedback). Finally, we changed the nature of the targets from requiring explicit force values presented as arrows on a force-feedback meter (explicit targets) to the more naturalistic and intuitive target forces implied by images of objects (implicit targets). With visual force feedback the relation between task difficulty and the time to produce the target grip force was predicted by Fitts' law (average r 2 = 0.82). Without vision, average grip force scaled accurately although force variability was insensitive to the target presented. In contrast, images of everyday objects generated more reliable grip forces without the visualized

  1. Cross Voltage Control with Inner Hysteresis Current Control for Multi-output Boost Converter

    DEFF Research Database (Denmark)

    Nami, Alireza; Zare, Firuz; Blaabjerg, Frede

    2009-01-01

    Multi-output boost (MOB) converter is a novel DC-DC converter unlike the regular boost converter, has the ability to share its total output voltage and to have different series output voltage from a given duty cycle for low and high power applications. In this paper, discrete voltage control...... with inner hysteresis current control loop has been proposed to keep the simplicity of the control law for the double-output MOB converter, which can be implemented by a combination of analogue and logical ICs or simple microcontroller to constrain the output voltages of MOB converter at their reference...... voltages against variation in load or input voltage. The salient features of the proposed control strategy are simplicity of implementation and ease to extend to multiple outputs in the MOB converter. Simulation and experimental results are presented to show the validity of control strategy....

  2. Using the modern CNC controllers capabilities for estimating the machining forces during the milling process

    Directory of Open Access Journals (Sweden)

    Breaz Radu-Eugen

    2017-01-01

    Full Text Available Machining forces can nowadays be measured by using 3D dynamometers, which are usually very expensive devices and hardly available for most of the CNC machine-tools users. On the other hand, modern CNC controllers have nowadays the ability to display and save many outputs within the machining process, such as the currents or even the torques at the shaft's level for the feed motors on each axis. These outputs can be used for estimating the machining forces, but it is to be noticed that the above-mentioned currents and torques are proportional with the overall resistant forces, which includes not only technological forces, but also friction, inertial and pre-tensioning forces. This paper presents an approach for estimating the machining forces during a milling process, by using the outputs stored in the CNC controller and separating the effects of technological forces from the other forces involved in the process. The separation was made by running two sets of experiments, one set for dry-run regime and the other one for machining regime.

  3. Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

    Science.gov (United States)

    Abdallah, Muhammad E (Inventor); Platt, Jr., Robert J. (Inventor); Reiland, Matthew J (Inventor); Hargrave, Brian (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Ihrke, Chris A. (Inventor)

    2013-01-01

    A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

  4. Product Distribution Theory for Control of Multi-Agent Systems

    Science.gov (United States)

    Lee, Chia Fan; Wolpert, David H.

    2004-01-01

    Product Distribution (PD) theory is a new framework for controlling Multi-Agent Systems (MAS's). First we review one motivation of PD theory, as the information-theoretic extension of conventional full-rationality game theory to the case of bounded rational agents. In this extension the equilibrium of the game is the optimizer of a Lagrangian of the (probability distribution of) the joint stare of the agents. Accordingly we can consider a team game in which the shared utility is a performance measure of the behavior of the MAS. For such a scenario the game is at equilibrium - the Lagrangian is optimized - when the joint distribution of the agents optimizes the system's expected performance. One common way to find that equilibrium is to have each agent run a reinforcement learning algorithm. Here we investigate the alternative of exploiting PD theory to run gradient descent on the Lagrangian. We present computer experiments validating some of the predictions of PD theory for how best to do that gradient descent. We also demonstrate how PD theory can improve performance even when we are not allowed to rerun the MAS from different initial conditions, a requirement implicit in some previous work.

  5. Adaptive, Distributed Control of Constrained Multi-Agent Systems

    Science.gov (United States)

    Bieniawski, Stefan; Wolpert, David H.

    2004-01-01

    Product Distribution (PO) theory was recently developed as a broad framework for analyzing and optimizing distributed systems. Here we demonstrate its use for adaptive distributed control of Multi-Agent Systems (MASS), i.e., for distributed stochastic optimization using MAS s. First we review one motivation of PD theory, as the information-theoretic extension of conventional full-rationality game theory to the case of bounded rational agents. In this extension the equilibrium of the game is the optimizer of a Lagrangian of the (Probability dist&&on on the joint state of the agents. When the game in question is a team game with constraints, that equilibrium optimizes the expected value of the team game utility, subject to those constraints. One common way to find that equilibrium is to have each agent run a Reinforcement Learning (E) algorithm. PD theory reveals this to be a particular type of search algorithm for minimizing the Lagrangian. Typically that algorithm i s quite inefficient. A more principled alternative is to use a variant of Newton's method to minimize the Lagrangian. Here we compare this alternative to RL-based search in three sets of computer experiments. These are the N Queen s problem and bin-packing problem from the optimization literature, and the Bar problem from the distributed RL literature. Our results confirm that the PD-theory-based approach outperforms the RL-based scheme in all three domains.

  6. Multi-Pass Malware Sandbox Analysis with Controlled Internet Connection

    Science.gov (United States)

    Yoshioka, Katsunari; Matsumoto, Tsutomu

    Malware sandbox analysis, in which a malware sample is actually executed in a testing environment (i.e. sandbox) to observe its behavior, is one of the promising approaches to tackling the emerging threats of exploding malware. As a lot of recent malware actively communicates with remote hosts over the Internet, sandboxes should also support an Internet connection, otherwise important malware behavior may not be observed. In this paper, we propose a multi-pass sandbox analysis with a controlled Internet connection. In the proposed method, we start our analysis with an isolated sandbox and an emulated Internet that consists of a set of dummy servers and hosts that run vulnerable services, called Honeypots in the Sandbox (HitS). All outbound connections from the victim host are closely inspected to see if they could be connected to the real Internet. We iterate the above process until no new behaviors are observed. We implemented the proposed method in a completely automated fashion and evaluated it with malware samples recently captured in the wild. Using a simple containment policy that authorizes only certain application protocols, namely, HTTP, IRC, and DNS, we were able to observe a greater variety of behaviors compared with the completely isolated sandbox. Meanwhile, we confirmed that a noticeable number of IP scans, vulnerability exploitations, and DoS attacks are successfully contained in the sandbox. Additionally, a brief comparison with two existing sandbox analysis systems, Norman Sandbox and CWSandbox, are shown.

  7. Ground reaction force comparison of controlled resistance methods to isoinertial loading of the squat exercise - biomed 2010.

    Science.gov (United States)

    Paulus, David C; Reynolds, Michael C; Schilling, Brian K

    2010-01-01

    The ground reaction force during the concentric (raising) portion of the squat exercise was compared to that of isoinertial loading (free weights) for three pneumatically controlled resistance methods: constant resistance, cam force profile, and proportional force control based on velocity. Constant force control showed lower ground reaction forces than isoinertial loading throughout the range of motion (ROM). The cam force profile exhibited slightly greater ground reaction forces than isoinertial loading at 10 and 40% ROM with fifty-percent greater loading at 70% ROM. The proportional force control consistently elicited greater ground reaction force than isoinertial loading, which progressively ranged from twenty to forty percent increase over isoinertial loading except for being approximately equal at 85% ROM. Based on these preliminary results, the proportional control shows the most promise for providing loading that is comparable in magnitude to isoinertial loading. This technology could optimize resistance exercise for sport-specific training or as a countermeasure to atrophy during spaceflight.

  8. Multi-focal Vision and Gaze Control Improve Navigation Performance

    Directory of Open Access Journals (Sweden)

    Kolja Kuehnlenz

    2008-11-01

    Full Text Available Multi-focal vision systems comprise cameras with various fields of view and measurement accuracies. This article presents a multi-focal approach to localization and mapping of mobile robots with active vision. An implementation of the novel concept is done considering a humanoid robot navigation scenario where the robot is visually guided through a structured environment with several landmarks. Various embodiments of multi-focal vision systems are investigated and the impact on navigation performance is evaluated in comparison to a conventional mono-focal stereo set-up. The comparative studies clearly show the benefits of multi-focal vision for mobile robot navigation: flexibility to assign the different available sensors optimally in each situation, enhancement of the visible field, higher localization accuracy, and, thus, better task performance, i.e. path following behavior of the mobile robot. It is shown that multi-focal vision may strongly improve navigation performance.

  9. Estimation of excitation forces for wave energy converters control using pressure measurements

    Science.gov (United States)

    Abdelkhalik, O.; Zou, S.; Robinett, R.; Bacelli, G.; Wilson, D.

    2017-08-01

    Most control algorithms of wave energy converters require prediction of wave elevation or excitation force for a short future horizon, to compute the control in an optimal sense. This paper presents an approach that requires the estimation of the excitation force and its derivatives at present time with no need for prediction. An extended Kalman filter is implemented to estimate the excitation force. The measurements in this approach are selected to be the pressures at discrete points on the buoy surface, in addition to the buoy heave position. The pressures on the buoy surface are more directly related to the excitation force on the buoy as opposed to wave elevation in front of the buoy. These pressure measurements are also more accurate and easier to obtain. A singular arc control is implemented to compute the steady-state control using the estimated excitation force. The estimated excitation force is expressed in the Laplace domain and substituted in the control, before the latter is transformed to the time domain. Numerical simulations are presented for a Bretschneider wave case study.

  10. On a multi-channel transportation loss system with controlled input and controlled service

    Directory of Open Access Journals (Sweden)

    Jewgeni Dshalalow

    1987-01-01

    Full Text Available A multi-channel loss queueing system is investigated. The input stream is a controlled point process. The service in each of m parallel channels depends on the state of the system at certain moments of time when input and service may be controlled. To obtain explicitly the limiting distribution of the main process (Zt (the number of busy channels in equilibrium, an auxiliary three dimensional process with two additional components (one of them is a semi-Markov process is treated as semi-regenerative process. An optimization problem is discussed. Simple expressions for an objective function are derived.

  11. Distributed Cooperative Control of Nonlinear and Non-identical Multi-agent Systems

    DEFF Research Database (Denmark)

    Bidram, Ali; Lewis, Frank; Davoudi, Ali

    2013-01-01

    This paper exploits input-output feedback linearization technique to implement distributed cooperative control of multi-agent systems with nonlinear and non-identical dynamics. Feedback linearization transforms the synchronization problem for a nonlinear and heterogeneous multi-agent system...... for electric power microgrids. The effectiveness of the proposed control is verified by simulating a microgrid test system....

  12. Multi-agent system-based event-triggered hybrid control scheme for energy internet

    DEFF Research Database (Denmark)

    Dou, Chunxia; Yue, Dong; Han, Qing Long

    2017-01-01

    This paper is concerned with an event-triggered hybrid control for the energy Internet based on a multi-agent system approach with which renewable energy resources can be fully utilized to meet load demand with high security and well dynamical quality. In the design of control, a multi-agent system...

  13. Design of a new adaptive fuzzy controller and its implementation for the damping force control of a magnetorheological damper

    International Nuclear Information System (INIS)

    Phu, Do Xuan; Shah, Kruti; Choi, Seung-Bok

    2014-01-01

    This paper presents a new adaptive fuzzy controller and its implementation for the damping force control of a magnetorheological (MR) fluid damper in order to validate the effectiveness of the control performance. An interval type 2 fuzzy model is built, and then combined with modified adaptive control to achieve the desired damping force. In the formulation of the new adaptive controller, an enhanced iterative algorithm is integrated with the fuzzy model to decrease the time of calculation (D Wu 2013 IEEE Trans. Fuzzy Syst. 21 80–99) and the control algorithm is synthesized based on the H ∞ tracking technique. In addition, for the verification of good control performance of the proposed controller, a cylindrical MR damper which can be applied to the vibration control of a washing machine is designed and manufactured. For the operating fluid, a recently developed plate-like particle-based MR fluid is used instead of a conventional MR fluid featuring spherical particles. To highlight the control performance of the proposed controller, two existing adaptive fuzzy control algorithms proposed by other researchers are adopted and altered for a comparative study. It is demonstrated from both simulation and experiment that the proposed new adaptive controller shows better performance of damping force control in terms of response time and tracking accuracy than the existing approaches. (papers)

  14. Explicit/multi-parametric model predictive control (MPC) of linear discrete-time systems by dynamic and multi-parametric programming

    KAUST Repository

    Kouramas, K.I.; Faí sca, N.P.; Panos, C.; Pistikopoulos, E.N.

    2011-01-01

    This work presents a new algorithm for solving the explicit/multi- parametric model predictive control (or mp-MPC) problem for linear, time-invariant discrete-time systems, based on dynamic programming and multi-parametric programming techniques

  15. Design of Robust AMB Controllers for Rotors Subjected to Varying and Uncertain Seal Forces

    DEFF Research Database (Denmark)

    Lauridsen, Jonas Skjødt; Santos, Ilmar

    2017-01-01

    This paper demonstrates the design and simulation results of model based controllers for AMB systems, subjectedto uncertain and changing dynamic seal forces. Specifically, a turbocharger with a hole-pattern seal mounted acrossthe balance piston is considered. The dynamic forces of the seal, which...... are dependent on the operational conditions,have a significant effect on the overall system dynamics. Furthermore, these forces are considered uncertain.The nominal and the uncertainty representation of the seal model are established using results from conventionalmodelling approaches, i.e. CFD and Bulkflow......, and experimental results. Three controllers are synthesized: I) AnH∞ controller based on nominal plant representation, II) A µ controller, designed to be robust against uncertaintiesin the dynamic seal model and III) a Linear Parameter Varying (LPV) controller, designed to provide a unifiedperformance over a large...

  16. Validation of engineering methods for predicting hypersonic vehicle controls forces and moments

    Science.gov (United States)

    Maughmer, M.; Straussfogel, D.; Long, L.; Ozoroski, L.

    1991-01-01

    This work examines the ability of the aerodynamic analysis methods contained in an industry standard conceptual design code, the Aerodynamic Preliminary Analysis System (APAS II), to estimate the forces and moments generated through control surface deflections from low subsonic to high hypersonic speeds. Predicted control forces and moments generated by various control effectors are compared with previously published wind-tunnel and flight-test data for three vehicles: the North American X-15, a hypersonic research airplane concept, and the Space Shuttle Orbiter. Qualitative summaries of the results are given for each force and moment coefficient and each control derivative in the various speed ranges. Results show that all predictions of longitudinal stability and control derivatives are acceptable for use at the conceptual design stage.

  17. Evaluation of higher order statistics parameters for multi channel sEMG using different force levels.

    Science.gov (United States)

    Naik, Ganesh R; Kumar, Dinesh K

    2011-01-01

    The electromyograpy (EMG) signal provides information about the performance of muscles and nerves. The shape of the muscle signal and motor unit action potential (MUAP) varies due to the movement of the position of the electrode or due to changes in contraction level. This research deals with evaluating the non-Gaussianity in Surface Electromyogram signal (sEMG) using higher order statistics (HOS) parameters. To achieve this, experiments were conducted for four different finger and wrist actions at different levels of Maximum Voluntary Contractions (MVCs). Our experimental analysis shows that at constant force and for non-fatiguing contractions, probability density functions (PDF) of sEMG signals were non-Gaussian. For lesser MVCs (below 30% of MVC) PDF measures tends to be Gaussian process. The above measures were verified by computing the Kurtosis values for different MVCs.

  18. A Reconfiguration Scheme for Accommodating Actuator Failures in Multi-Input, Multi-Output Flight Control Systems

    Science.gov (United States)

    Siwakosit, W.; Hess, R. A.; Bacon, Bart (Technical Monitor); Burken, John (Technical Monitor)

    2000-01-01

    A multi-input, multi-output reconfigurable flight control system design utilizing a robust controller and an adaptive filter is presented. The robust control design consists of a reduced-order, linear dynamic inversion controller with an outer-loop compensation matrix derived from Quantitative Feedback Theory (QFT). A principle feature of the scheme is placement of the adaptive filter in series with the QFT compensator thus exploiting the inherent robustness of the nominal flight control system in the presence of plant uncertainties. An example of the scheme is presented in a pilot-in-the-loop computer simulation using a simplified model of the lateral-directional dynamics of the NASA F18 High Angle of Attack Research Vehicle (HARV) that included nonlinear anti-wind up logic and actuator limitations. Prediction of handling qualities and pilot-induced oscillation tendencies in the presence of these nonlinearities is included in the example.

  19. Automated boundary interaction force control of micromanipulators with in situ applications to microsurgery

    International Nuclear Information System (INIS)

    Eslami, Sohrab; Jalili, Nader

    2012-01-01

    Most recent works on miniature tasks are concentrated on developing tools to take advantage of the visual servoing feedback to control the ultra-small interaction forces. This paper spans an extensive platform for automatic controlling of boundary interaction forces with high precision in the level of micro/nano-Newton with extensive micro/nanoengineering applications such as the microsurgery. To this end, a comprehensive piezoresistive microcantilever (PMC) model considering the shear deformation and rotary inertia effects treating as the distributed-parameters model along with the Hertzian contact force is presented. The purpose of considering the Hertzian contact force model is to investigate the dynamic response of the interaction force between the microcantilever's tip and the specimen. Afterward, a control platform is introduced to automatically manipulate the PMC to follow an ideal micro/nano-interaction force. By using the integrated PMC with the micromanipulator and a digital signal processor, an intuitive programming code is written to incorporate the micromanipulator and the controller in a real-time framework. To calibrate and verify the induced voltage in the PMC, a self-sensing experiment on the piezoelectric microcantilever is carried out to warrant the calibration procedure. Some experiments are established to affirm the validity of the proposed control for the autonomous real-time tasks on the boundary interaction force control. Unlike the conventional research studies, the measured force here contributes as the feedback source in contrast to the vision feedback while force sensors possess more precision, productivity and small size. This technique has several potential applications listed but not limited to the micro/nanomanipulation, developing artificial biological systems (e.g., fabricating hydrogel for the scaffold), and medicine such as microsurgery. As a result, using the proposed platform, we are able to manipulate and control the

  20. Interference-aware power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2009-09-01

    Full Text Available are well known in [9], [6]. The operation of multi-radio multi-channel (MRMC) WMNs generally requires sustainable energy supply. Substantial deployments of WMNs have recently been witnessed in rural and remote communities [4]. In such applications...]. Power resources are dynamically adjusted by each NIC using intra and inter-subsystem (channel) states. Due to the decentralized nature, each MP assumes imperfect knowledge about the global network. Further we assume that there exists...

  1. Biological forcing controls the chemistry of the coral exoskeleton

    Science.gov (United States)

    Meibom, A.; Mostefaoui, S.; Cuif, J.; Yurimoto, H.; Dauphin, Y.; Houlbreque, F.; Dunbar, R.; Constantz, B.

    2006-12-01

    A multitude of marine organisms produce calcium carbonate skeletons that are used extensively to reconstruct water temperature variability of the tropical and subtropical oceans - a key parameter in global climate-change models. Such paleo-climate reconstructions are based on the notion that skeletal oxygen isotopic composition and certain trace-element abundances (e.g., Sr/Ca and Mg/Ca ratios) vary in response to changes in the water temperature. However, it is a fundamental problem that poorly understood biological processes introduce large compositional deviations from thermodynamic equilibrium and hinder precise calibrations of many paleo-climate proxies. Indeed, the role of water temperature in controlling the composition of the skeleton is far from understood. We have studied trace-element abundances as well as oxygen and carbon isotopic compositions of individual skeletal components in the zooxanthellate and non-zooxanthellate corals at ultra-structural, i.e. micrometer to sub-micrometer length scales. From this body of work we draw the following, generalized conclusions: 1) Centers of calcification (COC) are not in equilibrium with seawater. Notably, the Sr/Ca ratio is higher than expected for aragonite equilibrium with seawater at the temperature at which the skeleton was formed. Furthermore, the COC are further away from equilibrium with seawater than fibrous skeleton in terms of stable isotope composition. 2) COC are dramatically different from the fibrous aragonite skeleton in terms of trace element composition. 3) Neither trace element nor stable isotope variations in the fibrous (bulk) part of the skeleton are directly related to changes in SST. In fact, changes in SST can have very little to do with the observed compositional variations. 4) Trace element variations in the fibrous (bulk) part of the skeleton are not related to the activity of zooxanthellae. These observations are directly relevant to the issue of biological versus non

  2. End-Point Contact Force Control with Quantitative Feedback Theory for Mobile Robots

    Directory of Open Access Journals (Sweden)

    Shuhuan Wen

    2012-12-01

    Full Text Available Robot force control is an important issue for intelligent mobile robotics. The end-point stiffness of a robot is a key and open problem in the research community. The control strategies are mostly dependent on both the specifications of the task and the environment of the robot. Due to the limited stiffness of the end-effector, we may adopt inherent torque to feedback the oscillations of the controlled force. This paper proposes an effective control strategy which contains a controller using quantitative feedback theory. The nested loop controllers take into account the physical limitation of the system's inner variables and harmful interference. The biggest advantage of the method is its simplicity in both the design process and the implementation of the control algorithm in engineering practice. Taking the one-link manipulator as an example, numerical experiments are carried out to verify the proposed control method. The results show the satisfactory performance.

  3. 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.

  4. Development of master slave system for interventional radiology with force-rate control

    International Nuclear Information System (INIS)

    Ide, Masaru; Zobel, P.B.; Claudio, P.D.; Mohri, Makoto; Komeda, Takashi

    2010-01-01

    The objective of this study is to develop a master-slave system for a catheter-guided operation, which is performed by using radiology, through the vascular system. When the master-slave system is used, the surgeon is not exposed to x-rays during the operation. The master tool is managed by an operator away from the slave tool, which is near the patient. The system must provide a realistic picture to the surgeon, particularly in term of force information because this operation is performed by observing three-dimensional fields on a two-dimensional monitor. In this paper, we describe the development of a master slave system that involves the use of force-rate control for guiding the catheter without using force sensors. The master tool has a force-display function. This system can be controlled by force and velocity controlling; hence, this system realized an innovative mechanism and algorism. Finally, the preliminary experiment indicated that the new control method was effective. Further, the force display was stable and achieved fast response. (author)

  5. iCub Whole-body Control through Force Regulation on Rigid Noncoplanar Contacts

    Directory of Open Access Journals (Sweden)

    Francesco eNori

    2015-03-01

    Full Text Available This paper details the implementation on the humanoid robot iCub of state-of-the-art algorithms for whole-body control. We regulate the forces between the robot and its surrounding environment to stabilize a desired robot posture. We assume that the forces and torques are exerted on rigid contacts. The validity of this assumption is guaranteed by constraining the contact forces and torques, e.g. the contact forces must belong to the associated friction cones. The implementation of this control strategy requires to estimate the external forces acting on the robot, and the internal joint torques. We then detail algorithms to obtain these estimations when using a robot with an iCub-like sensor set, i.e. distributed six-axis force-torque sensors and whole-body tactile sensors. A general theory for identifying the robot inertial parameters is also presented. From an actuation standpoint, we show how to implement a joint torque control in the case of DC brushless motors. In addition, the coupling mechanism of the iCub torso is investigated. The soundness of the entire control architecture is validated in a real scenario involving the robot iCub balancing and making contacts at both arms.

  6. Retrospective exposure assessment and quality control in an international multi-centre case-control study

    DEFF Research Database (Denmark)

    Tinnerberg, H; Heikkilä, P; Huici-Montagud, A

    2003-01-01

    The paper presents the exposure assessment method and quality control procedure used in an international, multi-centre case-control study within a joint Nordic and Italian cohort. This study was conducted to evaluate whether occupational exposure to carcinogens influenced the predictivity of high...... was higher among the original assessors (the assessor from the same country as the subject) than the average prevalence assessed by the other four in the quality control round. The original assessors classified more job situations as exposed than the others. Several reasons for this are plausible: real...... country-specific differences, differences in information available to the home assessor and the others and misunderstandings or difficulties in translation of information. To ensure the consistency of exposure assessments in international retrospective case-control studies it is important to have a well...

  7. Modelled radiative forcing of the direct aerosol effect with multi-observation evaluation

    Directory of Open Access Journals (Sweden)

    G. Myhre

    2009-02-01

    Full Text Available A high-resolution global aerosol model (Oslo CTM2 driven by meteorological data and allowing a comparison with a variety of aerosol observations is used to simulate radiative forcing (RF of the direct aerosol effect. The model simulates all main aerosol components, including several secondary components such as nitrate and secondary organic carbon. The model reproduces the main chemical composition and size features observed during large aerosol campaigns. Although the chemical composition compares best with ground-based measurement over land for modelled sulphate, no systematic differences are found for other compounds. The modelled aerosol optical depth (AOD is compared to remote sensed data from AERONET ground and MODIS and MISR satellite retrievals. To gain confidence in the aerosol modelling, we have tested its ability to reproduce daily variability in the aerosol content, and this is performing well in many regions; however, we also identified some locations where model improvements are needed. The annual mean regional pattern of AOD from the aerosol model is broadly similar to the AERONET and the satellite retrievals (mostly within 10–20%. We notice a significant improvement from MODIS Collection 4 to Collection 5 compared to AERONET data. Satellite derived estimates of aerosol radiative effect over ocean for clear sky conditions differs significantly on regional scales (almost up to a factor two, but also in the global mean. The Oslo CTM2 has an aerosol radiative effect close to the mean of the satellite derived estimates. We derive a radiative forcing (RF of the direct aerosol effect of −0.35 Wm−2 in our base case. Implementation of a simple approach to consider internal black carbon (BC mixture results in a total RF of −0.28 Wm−2. Our results highlight the importance of carbonaceous particles, producing stronger individual RF than considered in the recent IPCC estimate; however, net RF is less different

  8. ANALYTICAL SYNTHESIS OF FORCED PULSE ELECTRONIC DRIVE CONTROL OF A TRACKING SYSTEM

    Directory of Open Access Journals (Sweden)

    A. S. Abufanas

    2017-01-01

    Full Text Available The problem of analytical synthesis of a control signal by a linear dynamical system is considered. As an optimization criterion, it is proposed to consider the transition time of the system from the initial state to a given final state. This type of control is called forced, providing the maximum system speed. The principle of solving this problem is considered on the basis of application of uncertain Lagrange multipliers and the Pontryagin maximum principle. Expressions are obtained for the matrix of transitions of the system and the control signal in a vector form.As an example, the electric drive described by the widespread second-order mathematical model is considered to evaluate the efficiency of the proposed method. Qualitative illustrations of the operability of the proposed approach, obtained by modeling in the Mathcad environment, and quantitative characteristics of the change in the input and output signals of the hypothetical control system are presented. It is shown that the use of forced control does not lead to the output of variables characterizing the state of the system, beyond the limits of admissible values.The use of forced control makes it possible to synthesize the control law in the form of a sequence of rectangular pulses of constant amplitude determined by the power source, variable duty cycle and polarity. This approach can be used for the control of DC-type DC motors used in various tracking systems used on unmanned aerial vehicles. Key words: forced control, target function, electric drive, pulse train. The use of forced control makes it possible to synthesize the control law in the form of a sequence of rectangular pulses of constant amplitude determined by the power source, variable duty cycle and polarity. This approach can be used for the control of DC-type DC motors used in various tracking systems used on unmanned aerial vehicles.

  9. Controlling bi-partite entanglement in multi-qubit systems

    International Nuclear Information System (INIS)

    Plesch, Martin; Novotny, Jaroslav; Dzurakova, Zuzana; Buzek, VladimIr

    2004-01-01

    Bi-partite entanglement in multi-qubit systems cannot be shared freely. The rules of quantum mechanics impose bounds on how multi-qubit systems can be correlated. In this paper, we utilize a concept of entangled graphs with weighted edges in order to analyse pure quantum states of multi-qubit systems. Here qubits are represented by vertexes of the graph, while the presence of bi-partite entanglement is represented by an edge between corresponding vertexes. The weight of each edge is defined to be the entanglement between the two qubits connected by the edge, as measured by the concurrence. We prove that each entangled graph with entanglement bounded by a specific value of the concurrence can be represented by a pure multi-qubit state. In addition, we present a logic network with O(N 2 ) elementary gates that can be used for preparation of the weighted entangled graphs of N qubits

  10. Controlling bi-partite entanglement in multi-qubit systems

    Science.gov (United States)

    Plesch, Martin; Novotný, Jaroslav; Dzuráková, Zuzana; Buzek, Vladimír

    2004-02-01

    Bi-partite entanglement in multi-qubit systems cannot be shared freely. The rules of quantum mechanics impose bounds on how multi-qubit systems can be correlated. In this paper, we utilize a concept of entangled graphs with weighted edges in order to analyse pure quantum states of multi-qubit systems. Here qubits are represented by vertexes of the graph, while the presence of bi-partite entanglement is represented by an edge between corresponding vertexes. The weight of each edge is defined to be the entanglement between the two qubits connected by the edge, as measured by the concurrence. We prove that each entangled graph with entanglement bounded by a specific value of the concurrence can be represented by a pure multi-qubit state. In addition, we present a logic network with O(N2) elementary gates that can be used for preparation of the weighted entangled graphs of N qubits.

  11. Reliability analysis and component functional allocations for the ESF multi-loop controller design

    International Nuclear Information System (INIS)

    Hur, Seop; Kim, D.H.; Choi, J.K.; Park, J.C.; Seong, S.H.; Lee, D.Y.

    2006-01-01

    This paper deals with the reliability analysis and component functional allocations to ensure the enhanced system reliability and availability. In the Engineered Safety Features, functionally dependent components are controlled by a multi-loop controller. The system reliability of the Engineered Safety Features-Component Control System, especially, the multi-loop controller which is changed comparing to the conventional controllers is an important factor for the Probability Safety Assessment in the nuclear field. To evaluate the multi-loop controller's failure rate of the k-out-of-m redundant system, the binomial process is used. In addition, the component functional allocation is performed to tolerate a single multi-loop controller failure without the loss of vital operation within the constraints of the piping and component configuration, and ensure that mechanically redundant components remain functional. (author)

  12. Quantifying feedforward control: a linear scaling model for fingertip forces and object weight.

    Science.gov (United States)

    Lu, Ying; Bilaloglu, Seda; Aluru, Viswanath; Raghavan, Preeti

    2015-07-01

    The ability to predict the optimal fingertip forces according to object properties before the object is lifted is known as feedforward control, and it is thought to occur due to the formation of internal representations of the object's properties. The control of fingertip forces to objects of different weights has been studied extensively by using a custom-made grip device instrumented with force sensors. Feedforward control is measured by the rate of change of the vertical (load) force before the object is lifted. However, the precise relationship between the rate of change of load force and object weight and how it varies across healthy individuals in a population is not clearly understood. Using sets of 10 different weights, we have shown that there is a log-linear relationship between the fingertip load force rates and weight among neurologically intact individuals. We found that after one practice lift, as the weight increased, the peak load force rate (PLFR) increased by a fixed percentage, and this proportionality was common among the healthy subjects. However, at any given weight, the level of PLFR varied across individuals and was related to the efficiency of the muscles involved in lifting the object, in this case the wrist and finger extensor muscles. These results quantify feedforward control during grasp and lift among healthy individuals and provide new benchmarks to interpret data from neurologically impaired populations as well as a means to assess the effect of interventions on restoration of feedforward control and its relationship to muscular control. Copyright © 2015 the American Physiological Society.

  13. Optimization of Process Parameters of Edge Robotic Deburring with Force Control

    Directory of Open Access Journals (Sweden)

    Burghardt A.

    2016-12-01

    Full Text Available The issues addressed in the paper present a part of the scientific research conducted within the framework of the automation of the aircraft engine part manufacturing processes. The results of the research presented in the article provided information in which tolerances while using a robotic control station with the option of force control we can make edge deburring.

  14. Optimization of Process Parameters of Edge Robotic Deburring with Force Control

    Science.gov (United States)

    Burghardt, A.; Szybicki, D.; Kurc, K.; Muszyńska, M.

    2016-12-01

    The issues addressed in the paper present a part of the scientific research conducted within the framework of the automation of the aircraft engine part manufacturing processes. The results of the research presented in the article provided information in which tolerances while using a robotic control station with the option of force control we can make edge deburring.

  15. Template model inspired leg force feedback based control can assist human walking.

    Science.gov (United States)

    Zhao, Guoping; Sharbafi, Maziar; Vlutters, Mark; van Asseldonk, Edwin; Seyfarth, Andre

    2017-07-01

    We present a novel control approach for assistive lower-extremity exoskeletons. In particular, we implement a virtual pivot point (VPP) template model inspired leg force feedback based controller on a lower-extremity powered exoskeleton (LOPES II) and demonstrate that it can effectively assist humans during walking. It has been shown that the VPP template model is capable of stabilizing the trunk and reproduce a human-like hip torque during the stance phase of walking. With leg force and joint angle feedback inspired by the VPP template model, our controller provides hip and knee torque assistance during the stance phase. A pilot experiment was conducted with four healthy subjects. Joint kinematics, leg muscle electromyography (EMG), and metabolic cost were measured during walking with and without assistance. Results show that, for 0.6 m/s walking, our controller can reduce leg muscle activations, especially for the medial gastrocnemius (about 16.0%), while hip and knee joint kinematics remain similar to the condition without the controller. Besides, the controller also reduces 10% of the net metabolic cost during walking. This paper demonstrates walking assistance benefits of the VPP template model for the first time. The support of human walking is achieved by a force feedback of leg force applied to the control of hip and knee joints. It can help us to provide a framework for investigating walking assistance control in the future.

  16. An investigation into the organisation and structural design of multi-computer process-control systems

    International Nuclear Information System (INIS)

    Gertenbach, W.P.

    1981-12-01

    A multi-computer system for the collection of data and control of distributed processes has been developed. The structure and organisation of this system, a study of the general theory of systems and of modularity was used as a basis for an investigation into the organisation and structured design of multi-computer process-control systems. A multi-dimensional model of multi-computer process-control systems was developed. In this model a strict separation was made between organisational properties of multi-computer process-control systems and implementation dependant properties. The model was based on the principles of hierarchical analysis and modularity. Several notions of hierarchy were found necessary to describe fully the organisation of multi-computer systems. A new concept, that of interconnection abstraction was identified. This concept is an extrapolation of implementation techniques in the hardware implementation area to the software implementation area. A synthesis procedure which relies heavily on the above described analysis of multi-computer process-control systems is proposed. The above mentioned model, and a set of performance factors which depend on a set of identified design criteria, were used to constrain the set of possible solutions to the multi-computer process-control system synthesis-procedure

  17. Coping with Uncertainty: The Joint Task Force and Multi-Service Military Operations

    Science.gov (United States)

    1991-05-10

    DATE =3. REPORT TYPE AND DATIS COVERED 10 -1y II ION060Nr1 4. TITLE AND SUBTITLE S. FUNDING NUMBERS cO6p i tý6, LJrTi i u N csr .-r. AJ 7y1.; -n E ryo...responsible for keeping French Morocco under control and for invading Spanish Morocco should the Franco regime become less than neutral.57 Axis control...of Ital~y, 11. 57 Ibid., 55. LT’G Mark Clark, commziandiny Fifth U.S. Army in French Morocco , would have been selected to lead the American task

  18. Market-based control strategy for long-span structures considering the multi-time delay issue

    Science.gov (United States)

    Li, Hongnan; Song, Jianzhu; Li, Gang

    2017-01-01

    To solve the different time delays that exist in the control device installed on spatial structures, in this study, discrete analysis using a 2 N precise algorithm was selected to solve the multi-time-delay issue for long-span structures based on the market-based control (MBC) method. The concept of interval mixed energy was introduced from computational structural mechanics and optimal control research areas, and it translates the design of the MBC multi-time-delay controller into a solution for the segment matrix. This approach transforms the serial algorithm in time to parallel computing in space, greatly improving the solving efficiency and numerical stability. The designed controller is able to consider the issue of time delay with a linear controlling force combination and is especially effective for large time-delay conditions. A numerical example of a long-span structure was selected to demonstrate the effectiveness of the presented controller, and the time delay was found to have a significant impact on the results.

  19. Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

    Science.gov (United States)

    Zaal, Peter M. T.; Sweet, Barbara T.

    2012-01-01

    Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

  20. An experimental study of the velocity-forced flame response of a lean-premixed multi-nozzle can combustor for gas turbines

    Science.gov (United States)

    Szedlmayer, Michael Thomas

    The velocity forced flame response of a multi-nozzle, lean-premixed, swirl-stabilized, turbulent combustor was investigated at atmospheric pressure. The purpose of this study was to analyze the mechanisms that allowed velocity fluctuations to cause fluctuations in the rate of heat release in a gas turbine combustor experiencing combustion instability. Controlled velocity fluctuations were introduced to the combustor by a rotating siren device which periodically allowed the air-natural gas mixture to flow. The velocity fluctuation entering the combustor was measured using the two-microphone method. The resulting heat release rate fluctuation was measured using CH* chemiluminescence. The global response of the flame was quantified using the flame transfer function with the velocity fluctuation as the input and the heat release rate fluctuation as the output. Velocity fluctuation amplitude was initially maintained at 5% of the inlet velocity in order to remain in the linear response regime. Flame transfer function measurements were acquired at a wide range of operating conditions and forcing frequencies. The selected range corresponds to the conditions and instability frequencies typical of real gas turbine combustors. Multi-nozzle flame transfer functions were found to bear a qualitative similarity to the single-nozzle flame transfer functions in the literature. The flame transfer function gain exhibited alternating minima and maxima while the phase decreased linearly with increasing forcing frequency. Several normalization techniques were applied to all flame transfer function data in an attempt to collapse the data into a single curve. The best collapse was found to occur using a Strouhal number which was the ratio of the characteristic flame length to the wavelength of the forced disturbance. Critical values of Strouhal number are used to predict the shedding of vortical structures in shear layers. Because of the collapse observed when the flame transfer functions

  1. Cooperative control of multi-agent systems optimal and adaptive design approaches

    CERN Document Server

    Lewis, Frank L; Hengster-Movric, Kristian; Das, Abhijit

    2014-01-01

    Task complexity, communication constraints, flexibility and energy-saving concerns are all factors that may require a group of autonomous agents to work together in a cooperative manner. Applications involving such complications include mobile robots, wireless sensor networks, unmanned aerial vehicles (UAVs), spacecraft, and so on. In such networked multi-agent scenarios, the restrictions imposed by the communication graph topology can pose severe problems in the design of cooperative feedback control systems.  Cooperative control of multi-agent systems is a challenging topic for both control theorists and practitioners and has been the subject of significant recent research. Cooperative Control of Multi-Agent Systems extends optimal control and adaptive control design methods to multi-agent systems on communication graphs.  It develops Riccati design techniques for general linear dynamics for cooperative state feedback design, cooperative observer design, and cooperative dynamic output feedback design.  B...

  2. A novel feedback control system – Controlling the material flow in deep drawing using distributed blank-holder force

    DEFF Research Database (Denmark)

    Endelt, Benny Ørtoft; Tommerup, Søren; Danckert, Joachim

    2013-01-01

    The performance of a feedback control system is often limited by the quality of the model on which it is based, and often the controller design is based on trial and error due to insufficient modeling capabilities. A framework is proposed where the controller design is based on classical state...... on a deep drawing operation where the objective was to control material flow throughout the part using only spatial information regarding flange draw-in. The control system controls both the magnitude and distribution of the blank-holder force. The methodology proved stable and flexible with respect...

  3. Timing at peak force may be the hidden target controlled in continuation and synchronization tapping.

    Science.gov (United States)

    Du, Yue; Clark, Jane E; Whitall, Jill

    2017-05-01

    Timing control, such as producing movements at a given rate or synchronizing movements to an external event, has been studied through a finger-tapping task where timing is measured at the initial contact between finger and tapping surface or the point when a key is pressed. However, the point of peak force is after the time registered at the tapping surface and thus is a less obvious but still an important event during finger tapping. Here, we compared the time at initial contact with the time at peak force as participants tapped their finger on a force sensor at a given rate after the metronome was turned off (continuation task) or in synchrony with the metronome (sensorimotor synchronization task). We found that, in the continuation task, timing was comparably accurate between initial contact and peak force. These two timing events also exhibited similar trial-by-trial statistical dependence (i.e., lag-one autocorrelation). However, the central clock variability was lower at the peak force than the initial contact. In the synchronization task, timing control at peak force appeared to be less variable and more accurate than that at initial contact. In addition to lower central clock variability, the mean SE magnitude at peak force (SEP) was around zero while SE at initial contact (SEC) was negative. Although SEC and SEP demonstrated the same trial-by-trial statistical dependence, we found that participants adjusted the time of tapping to correct SEP, but not SEC, toward zero. These results suggest that timing at peak force is a meaningful target of timing control, particularly in synchronization tapping. This result may explain the fact that SE at initial contact is typically negative as widely observed in the preexisting literature.

  4. 3D force control for robotic-assisted beating heart surgery based on viscoelastic tissue model.

    Science.gov (United States)

    Liu, Chao; Moreira, Pedro; Zemiti, Nabil; Poignet, Philippe

    2011-01-01

    Current cardiac surgery faces the challenging problem of heart beating motion even with the help of mechanical stabilizer which makes delicate operation on the heart surface difficult. Motion compensation methods for robotic-assisted beating heart surgery have been proposed recently in literature, but research on force control for such kind of surgery has hardly been reported. Moreover, the viscoelasticity property of the interaction between organ tissue and robotic instrument further complicates the force control design which is much easier in other applications by assuming the interaction model to be elastic (industry, stiff object manipulation, etc.). In this work, we present a three-dimensional force control method for robotic-assisted beating heart surgery taking into consideration of the viscoelastic interaction property. Performance studies based on our D2M2 robot and 3D heart beating motion information obtained through Da Vinci™ system are provided.

  5. Multi-objective PID Optimization for Speed Control of an Isolated Steam Turbine using Gentic Algorithm

    OpenAIRE

    Sanjay Kr. Singh; D. Boolchandani; S.G. Modani; Nitish Katal

    2014-01-01

    This study focuses on multi-objective optimization of the PID controllers for optimal speed control for an isolated steam turbine. In complex operations, optimal tuning plays an imperative role in maintaining the product quality and process safety. This study focuses on the comparison of the optimal PID tuning using Multi-objective Genetic Algorithm (NSGA-II) against normal genetic algorithm and Ziegler Nichols methods for the speed control of an isolated steam turbine. Isolated steam turbine...

  6. The Control Based on Internal Average Kinetic Energy in Complex Environment for Multi-robot System

    Science.gov (United States)

    Yang, Mao; Tian, Yantao; Yin, Xianghua

    In this paper, reference trajectory is designed according to minimum energy consumed for multi-robot system, which nonlinear programming and cubic spline interpolation are adopted. The control strategy is composed of two levels, which lower-level is simple PD control and the upper-level is based on the internal average kinetic energy for multi-robot system in the complex environment with velocity damping. Simulation tests verify the effectiveness of this control strategy.

  7. Adaptive Droop Control for Microgrids Based on the Synergetic Control of Multi-Agent Systems

    Directory of Open Access Journals (Sweden)

    Zhiwen Yu

    2016-12-01

    Full Text Available In this paper, a distributed synergetic control based on multi-agent systems is proposed to solve the problems of frequency and voltage errors, system stability and power sharing accuracy in the traditional droop control of microgrids. Starting with power flow equations, we build the secondary-order dynamic model of DG, which consists of three parts: (1 active power allocation; (2 active power-frequency; and (3 reactive power-voltage droop control. Considering time-delays in communication networks, a leaderless synergetic control algorithm is proposed to allocate the active power in inverse proportion to the droop coefficient, and the synergetic control with a virtual leader is proposed to control the system frequency and voltage to keep at the expected value. Besides, the direct Lyapunov method is introduced to verify the globally asymptotical stability. Moreover, the impacts of communication disturbance are also discussed from the aspects of control precision and system stability. Finally, based on a test microgrid, numerous cases are designed as illustration, and the simulation results validate the proposed method.

  8. Reproducing multi-model ensemble average with Ensemble-averaged Reconstructed Forcings (ERF) in regional climate modeling

    Science.gov (United States)

    Erfanian, A.; Fomenko, L.; Wang, G.

    2016-12-01

    Multi-model ensemble (MME) average is considered the most reliable for simulating both present-day and future climates. It has been a primary reference for making conclusions in major coordinated studies i.e. IPCC Assessment Reports and CORDEX. The biases of individual models cancel out each other in MME average, enabling the ensemble mean to outperform individual members in simulating the mean climate. This enhancement however comes with tremendous computational cost, which is especially inhibiting for regional climate modeling as model uncertainties can originate from both RCMs and the driving GCMs. Here we propose the Ensemble-based Reconstructed Forcings (ERF) approach to regional climate modeling that achieves a similar level of bias reduction at a fraction of cost compared with the conventional MME approach. The new method constructs a single set of initial and boundary conditions (IBCs) by averaging the IBCs of multiple GCMs, and drives the RCM with this ensemble average of IBCs to conduct a single run. Using a regional climate model (RegCM4.3.4-CLM4.5), we tested the method over West Africa for multiple combination of (up to six) GCMs. Our results indicate that the performance of the ERF method is comparable to that of the MME average in simulating the mean climate. The bias reduction seen in ERF simulations is achieved by using more realistic IBCs in solving the system of equations underlying the RCM physics and dynamics. This endows the new method with a theoretical advantage in addition to reducing computational cost. The ERF output is an unaltered solution of the RCM as opposed to a climate state that might not be physically plausible due to the averaging of multiple solutions with the conventional MME approach. The ERF approach should be considered for use in major international efforts such as CORDEX. Key words: Multi-model ensemble, ensemble analysis, ERF, regional climate modeling

  9. Multi-echelon, multi-indenture spare parts inventory control subject to system availability and budget constraints

    International Nuclear Information System (INIS)

    Costantino, Francesco; Di Gravio, Giulio; Tronci, Massimo

    2013-01-01

    Inventory management of spare parts is one of the most critical issues in the aeronautical industry, given the required level of system availability related to the strategic importance and high stocking costs of the components. Even if a large number of spare parts increases warehousing costs, every single shortage have a greater impact: the adoption of best-in-class inventory management techniques becomes crucial. On these considerations, the paper presents an innovative model of spare parts allocation for the Italian Air Force with the aim of minimizing backorders and, at the same time, ensuring an availability of 99% depending on the actual flight plan. The model, solved by a marginal analysis, considers an original configuration of features combining different skills of maintenance centers in a hierarchical multi-echelon, multi-item, multi-indenture structure. A real case is provided in order to analyze the solving method and the results. -- Highlights: •We studied a problem of allocations for spare parts of aeronautical systems. •The model presents different repair capabilities of maintenance centers. •The model fits constraints on budget and on total operational availability. •The model is solved by a marginal analysis with a backorder/price ratio. •A numerical example shows a spare parts allocation with relative considerations

  10. The Director of Mobility Forces' Role in the Command Control of Air Mobility Assets During Humanitarian Relief Operations

    National Research Council Canada - National Science Library

    Bush, Timothy E

    2000-01-01

    ...). Air Force doctrine recommends a command and control (C2) structure that permits the same organizational concept to be used throughout the spectrum of conflict, tailored to suit the specific operational objectives of a Joint Task Force (JFT...

  11. Demonstrating multi-layered MAS in control of offshore oil and gas production

    DEFF Research Database (Denmark)

    Lindegaard Mikkelsen, Lars; Næumann, J. R.; Demazeau, Y.

    2013-01-01

    From a control perspective, offshore oil and gas production is very challenging due to the many and potentially conflicting production objectives that arise from the intrinsic complexity of the oil and gas domain. In this paper, we demonstrate how a multi-layered multi-agent system can be used in...

  12. Controls on Arctic sea ice from first-year and multi-year ice survival rates

    Science.gov (United States)

    Armour, K.; Bitz, C. M.; Hunke, E. C.; Thompson, L.

    2009-12-01

    The recent decrease in Arctic sea ice cover has transpired with a significant loss of multi-year (MY) ice. The transition to an Arctic that is populated by thinner first-year (FY) sea ice has important implications for future trends in area and volume. We develop a reduced model for Arctic sea ice with which we investigate how the survivability of FY and MY ice control various aspects of the sea-ice system. We demonstrate that Arctic sea-ice area and volume behave approximately as first-order autoregressive processes, which allows for a simple interpretation of September sea-ice in which its mean state, variability, and sensitivity to climate forcing can be described naturally in terms of the average survival rates of FY and MY ice. This model, used in concert with a sea-ice simulation that traces FY and MY ice areas to estimate the survival rates, reveals that small trends in the ice survival rates explain the decline in total Arctic ice area, and the relatively larger loss of MY ice area, over the period 1979-2006. Additionally, our model allows for a calculation of the persistence time scales of September area and volume anomalies. A relatively short memory time scale for ice area (~ 1 year) implies that Arctic ice area is nearly in equilibrium with long-term climate forcing at all times, and therefore observed trends in area are a clear indication of a changing climate. A longer memory time scale for ice volume (~ 5 years) suggests that volume can be out of equilibrium with climate forcing for long periods of time, and therefore trends in ice volume are difficult to distinguish from its natural variability. With our reduced model, we demonstrate the connection between memory time scale and sensitivity to climate forcing, and discuss the implications that a changing memory time scale has on the trajectory of ice area and volume in a warming climate. Our findings indicate that it is unlikely that a “tipping point” in September ice area and volume will be

  13. Shape Sensing Using a Multi-Core Optical Fiber Having an Arbitrary Initial Shape in the Presence of Extrinsic Forces

    Science.gov (United States)

    Rogge, Matthew D. (Inventor); Moore, Jason P. (Inventor)

    2014-01-01

    Shape of a multi-core optical fiber is determined by positioning the fiber in an arbitrary initial shape and measuring strain over the fiber's length using strain sensors. A three-coordinate p-vector is defined for each core as a function of the distance of the corresponding cores from a center point of the fiber and a bending angle of the cores. The method includes calculating, via a controller, an applied strain value of the fiber using the p-vector and the measured strain for each core, and calculating strain due to bending as a function of the measured and the applied strain values. Additionally, an apparent local curvature vector is defined for each core as a function of the calculated strain due to bending. Curvature and bend direction are calculated using the apparent local curvature vector, and fiber shape is determined via the controller using the calculated curvature and bend direction.

  14. Controllability of multi-partite quantum systems and selective excitation of quantum dots

    International Nuclear Information System (INIS)

    Schirmer, S G; Pullen, I C H; Solomon, A I

    2005-01-01

    We consider the degrees of controllability of multi-partite quantum systems, as well as necessary and sufficient criteria for each case. The results are applied to the problem of simultaneous control of an ensemble of quantum dots with a single laser pulse. Finally, we apply optimal control techniques to demonstrate selective excitation of individual dots for a simultaneously controllable ensemble of quantum dots

  15. Fractional order PID control design for semi-active control of smart base-isolated structures: A multi-objective cuckoo search approach.

    Science.gov (United States)

    Zamani, Abbas-Ali; Tavakoli, Saeed; Etedali, Sadegh

    2017-03-01

    Fractional order PID (FOPID) controllers are introduced as a general form of classical PID controllers using fractional calculus. As this controller provides good disturbance rejection and is robust against plant uncertainties it is appropriate for the vibration mitigation in structures. In this paper, an FOPID controller is designed to adjust the contact force of piezoelectric friction dampers for semi-active control of base-isolated structures during far-field and near-field earthquake excitations. A multi-objective cuckoo search algorithm is employed to tune the controller parameters. Considering the resulting Pareto optimal front, the best input for the FOPID controller is selected. For seven pairs of earthquakes and nine performance indices, the performance of the proposed controller is compared with those provided by several well-known control techniques. According to the simulation results, the proposed controller performs better than other controllers in terms of simultaneous reduction of the maximum base displacement and story acceleration for various types of earthquakes. Also, it provides acceptable responses in terms of inter-story drifts, root mean square of base displacements and floor acceleration. In addition, the evaluation of robustness for a stiffness uncertainty of ±10% indicates that the proposed controller gives a robust performance against such modeling errors. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Design of Optimal Hybrid Position/Force Controller for a Robot Manipulator Using Neural Networks

    Directory of Open Access Journals (Sweden)

    Vikas Panwar

    2007-01-01

    Full Text Available The application of quadratic optimization and sliding-mode approach is considered for hybrid position and force control of a robot manipulator. The dynamic model of the manipulator is transformed into a state-space model to contain two sets of state variables, where one describes the constrained motion and the other describes the unconstrained motion. The optimal feedback control law is derived solving matrix differential Riccati equation, which is obtained using Hamilton Jacobi Bellman optimization. The optimal feedback control law is shown to be globally exponentially stable using Lyapunov function approach. The dynamic model uncertainties are compensated with a feedforward neural network. The neural network requires no preliminary offline training and is trained with online weight tuning algorithms that guarantee small errors and bounded control signals. The application of the derived control law is demonstrated through simulation with a 4-DOF robot manipulator to track an elliptical planar constrained surface while applying the desired force on the surface.

  17. Comparison of two temperature control techniques in a forced water heater solar system

    Science.gov (United States)

    Hernández, E.; E Guzmán, R.; Santos, A.; Cordoba, E.

    2017-12-01

    a study on the performance of a forced solar heating system in which a comparative analysis of two control strategies, including the classic on-off control and PID control is presented. From the experimental results it was found that the two control strategies show a similar behaviour in the solar heating system forced an approximate settling time of 60 min and over-elongation 2°C for the two control strategies. Furthermore, the maximum temperature in the storage tank was 46°C and the maximum efficiency of flat plate collector was 76.7% given that this efficiency is the ratio of the energy of the radiation on the collector and the energy used to heat water. The efficiency obtained is a fact well accepted because the business efficiencies of flat plate collectors are approximately 70%.

  18. External Periodic Force Control of a Single-Degree-of-Freedom Vibroimpact System

    Directory of Open Access Journals (Sweden)

    Jingyue Wang

    2013-01-01

    Full Text Available A single-degree-of-freedom mechanical model of vibro-impact system is established. Bifurcation and chaos in the system are revealed with the time history diagram, phase trajectory map, and Poincaré map. According to the bifurcation and chaos of the actual vibro-impact system, the paper puts forward external periodic force control strategy. The method of controlling chaos by external periodic force feedback controller is developed to guide chaotic motions towards regular motions. The stability of the control system is also analyzed especially by theory. By selecting appropriate feedback coefficients, the unstable periodic orbits of the original chaotic orbit can be stabilized to the stable periodic orbits. The effectiveness of this control method is verified by numerical simulation.

  19. Design of Active Magnetic Bearing Controllers for Rotors Subjected to Gas Seal Forces

    DEFF Research Database (Denmark)

    Lauridsen, Jonas Skjødt; Santos, Ilmar F.

    2018-01-01

    Proper design of feedback controllers is crucial for ensuring high performance of Active Magnetic Bearing (AMB) supported rotor dynamic systems. Annular seals in those systems can contribute with significant forces, which, in many cases, are hard to model in advance due to complex geometries...... of the seal and multiphase fluids. Hence, it can be challenging to design AMB controllers that will guarantee robust performance for these kinds of systems. This paper demonstrates the design, simulation and experimental results of model based controllers for AMB systems, subjected to dynamic seal forces....... The controllers are found using H-infinity - and µ synthesis and are based on a global rotor dynamic model in-which the seal coefficients are identified in-situ. The controllers are implemented in a rotor-dynamic test facility with two radial AMBs and one annular seal with an adjustable inlet pressure. The seal...

  20. Self Organized Multi Agent Swarms (SOMAS) for Network Security Control

    Science.gov (United States)

    2009-03-01

    A. Van Veldhuizen . Evolutionary Algorithms for Solving Multi-Objective Problems, chapter MOEA Parallelization. Springer, 2007. 37. Das, Subrata...Mike P. and Willem-Jan van den Heuvel. Service Oriented Architectures: Approaches, Technologies, and Research Issues. Technical report, Tilburg...Tanenbaum, Andrew S. and Maarten Van Steen. Distributed Systems: Principles and Paradigms. Prentice Hall, 2006. 128. Thomas, Tavaris J. Fire Ant: An

  1. Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant

    Directory of Open Access Journals (Sweden)

    Puchalski Bartosz

    2015-12-01

    Full Text Available In the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller which is designed for nominal power level of the nuclear reactor operates insufficiently well in wide range of operational conditions, especially at the low thermal power level. Thus the steam generator is often controlled manually by operators. Incorrect water level in the steam generator may lead to accidental shutdown of the nuclear reactor and consequently financial losses. In the paper a comparison of proposed multi region fuzzy logic controller and traditional PID controllers designed only for nominal condition is presented. The gains of the local PID controllers have been derived by solving appropriate optimization tasks with the cost function in a form of integrated squared error (ISE criterion. In both cases, a model of steam generator which is readily available in literature was used for control algorithms synthesis purposes. The proposed multi-region fuzzy logic controller and traditional PID controller were subjected to broad-based simulation tests in rapid prototyping software - Matlab/Simulink. These tests proved the advantage of multi-region fuzzy logic controller with local PID controllers over its traditional counterpart.

  2. Active Control of Contact Force for a Pantograph-Catenary System

    Directory of Open Access Journals (Sweden)

    Jiqiang Wang

    2016-01-01

    Full Text Available The performance of the high speed trains depends critically on the quality of the contact in the pantograph-catenary interaction. Maintaining a constant contact force needs taking special measures and one of the methods is to utilize active control to optimize the contact force. A number of active control methods have been proposed in the past decade. However, the primary objective of these methods has been to reduce the variation of the contact force in the pantograph-catenary system, ignoring the effects of locomotive vibrations on pantograph-catenary dynamics. Motivated by the problems in active control of vibration in large scale structures, the author has developed a geometric framework specifically targeting the remote vibration suppression problem based only on local control action. It is the intention of the paper to demonstrate its potential in the active control of the pantograph-catenary interaction, aiming to minimize the variation of the contact force while simultaneously suppressing the vibration disturbance from the train. A numerical study is provided through the application to a simplified pantograph-catenary model.

  3. Kinesthetic Force Feedback and Belt Control for the Treadport Locomotion Interface.

    Science.gov (United States)

    Hejrati, Babak; Crandall, Kyle L; Hollerbach, John M; Abbott, Jake J

    2015-01-01

    This paper describes an improved control system for the Treadport immersive locomotion interface, with results that generalize to any treadmill that utilizes an actuated tether to enable self-selected walking speed. A new belt controller is implemented to regulate the user's position; when combined with the user's own volition, this controller also enables the user to naturally self-select their walking speed as they would when walking over ground. A new kinesthetic-force-feedback controller is designed for the tether that applies forces to the user's torso. This new controller is derived based on maintaining the user's sense of balance during belt acceleration, rather than by rendering an inertial force as was done in our prior work. Based on the results of a human-subjects study, the improvements in both controllers significantly contribute to an improved perception of realistic walking on the Treadport. The improved control system uses intuitive dynamic-system and anatomical parameters and requires no ad hoc gain tuning. The control system simply requires three measurements to be made for a given user: the user's mass, the user's height, and the height of the tether attachment point on the user's torso.

  4. Architectural study of the design and operation of advanced force feedback manual controllers

    Science.gov (United States)

    Tesar, Delbert; Kim, Whee-Kuk

    1990-01-01

    A teleoperator system consists of a manual controller, control hardware/software, and a remote manipulator. It was employed in either hazardous or unstructured, and/or remote environments. In teleoperation, the main-in-the-loop is the central concept that brings human intelligence to the teleoperator system. When teleoperation involves contact with an uncertain environment, providing the feeling of telepresence to the human operator is one of desired characteristics of the teleoperator system. Unfortunately, most available manual controllers in bilateral or force-reflecting teleoperator systems can be characterized by their bulky size, high costs, or lack of smoothness and transparency, and elementary architectures. To investigate other alternatives, a force-reflecting, 3 degree of freedom (dof) spherical manual controller is designed, analyzed, and implemented as a test bed demonstration in this research effort. To achieve an improved level of design to meet criteria such as compactness, portability, and a somewhat enhanced force-reflecting capability, the demonstration manual controller employs high gear-ratio reducers. To reduce the effects of the inertia and friction on the system, various force control strategies are applied and their performance investigated. The spherical manual controller uses a parallel geometry to minimize inertial and gravitational effects on its primary task of transparent information transfer. As an alternative to the spherical 3-dof manual controller, a new conceptual (or parallel) spherical 3-dof module is introduced with a full kinematic analysis. Also, the resulting kinematic properties are compared to those of other typical spherical 3-dof systems. The conceptual design of a parallel 6-dof manual controller and its kinematic analysis is presented. This 6-dof manual controller is similar to the Stewart Platform with the actuators located on the base to minimize the dynamic effects. Finally, a combination of the new 3-dof and 6-dof

  5. Decentralized power control for multi-radio multi-channel wireless mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2010-09-01

    Full Text Available control problems. However, such contributions can not solve the power control problems in MRMC configurations because of the architectural and structural differences amongst them. This paper presents a dynamic power control for MRMC WMNs. First, WMN...

  6. Multi-model for the control design and diagnosis of multi-sources ...

    African Journals Online (AJOL)

    Les équations analytiques de redondances sont introduites pour le diagnostic des systèmes électriques hybrides afin de détecter et d'isoler les défauts qui peuvent affecter les capteurs de courants et de tensions utilisés dans la commande de ces systèmes. This paper concerns multi-sources renewable energy systems.

  7. Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

    International Nuclear Information System (INIS)

    Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

    2015-01-01

    A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s. (paper)

  8. Hybrid PD and effective multi-mode positive position feedback control for slewing and vibration suppression of a smart flexible manipulator

    Science.gov (United States)

    Lou, Jun-qiang; Wei, Yan-ding; Yang, Yi-ling; Xie, Feng-ran

    2015-03-01

    A hybrid control strategy for slewing and vibration suppression of a smart flexible manipulator is presented in this paper. It consists of a proportional derivative controller to realize motion control, and an effective multi-mode positive position feedback (EMPPF) controller to suppress the multi-mode vibration. Rather than treat each mode equally as the standard multi-mode PPF, the essence of the EMPPF is that control forces of different modes are applied according to the mode parameters of the respective modes, so the vibration modes with less vibration energy receive fewer control forces. Stability conditions for the close loop system are established through stability analysis. Optimal parameters of the EMPPF controller are obtained using the method of root locus analysis. The performance of the proposed strategy is demonstrated by simulation and experiments. Experimental results show that the first two vibration modes of the manipulator are effectively suppressed. The setting time of the setup descends approximately 55%, reaching 3.12 s from 5.67 s.

  9. 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).

  10. 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.

  11. Bandwidth Controllable Tunable Filter for Hyper-/Multi-Spectral Imager, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposal introduces a fast speed bandwidth controllable tunable filter for hyper-/multi-spectral (HS/MS) imagers. It dynamically passes a variable...

  12. Multi-Temperature Zone, Droplet-based Microreactor for Increased Temperature Control in Nanoparticle Synthesis

    KAUST Repository

    Erdem, E. Yegâ n; Cheng, Jim C.; Doyle, Fiona M.; Pisano, Albert P.

    2013-01-01

    Microreactors are an emerging technology for the controlled synthesis of nanoparticles. The Multi-Temperature zone Microreactor (MTM) described in this work utilizes thermally isolated heated and cooled regions for the purpose of separating

  13. Multi-time-step domain coupling method with energy control

    DEFF Research Database (Denmark)

    Mahjoubi, N.; Krenk, Steen

    2010-01-01

    the individual time step. It is demonstrated that displacement continuity between the subdomains leads to cancelation of the interface contributions to the energy balance equation, and thus stability and algorithmic damping properties of the original algorithms are retained. The various subdomains can...... by a numerical example using a refined mesh around concentrated forces. Copyright © 2010 John Wiley & Sons, Ltd....

  14. A Comparison between Two Force-Position Controllers with Gravity Compensation Simulated on a Humanoid Arm

    Directory of Open Access Journals (Sweden)

    Giovanni Gerardo Muscolo

    2013-01-01

    Full Text Available The authors propose a comparison between two force-position controllers with gravity compensation simulated on the DEXTER bioinspired robotic arm. The two controllers are both constituted by an internal proportional-derivative (PD closed-loop for the position control. The force control of the two systems is composed of an external proportional (P closed-loop for one system (P system and an external proportional-integrative (PI closed-loop for the other system (PI system. The simulation tests performed with the two systems on a planar representation of the DEXTER, an eight-DOF bioinspired arm, showed that by varying the stiffness of the environment, with a correct setting of parameters, both systems ensure the achievement of the desired force regime and with great precision the desired position. The two controllers do not have large differences in performance when interacting with a lower stiffness environment. In case of an environment with greater rigidity, the PI system is more stable. The subsequent implementation of these control systems on the DEXTER robotic bioinspired arm gives guidance on the design and control optimisation of the arms of the humanoid robot named SABIAN.

  15. Performance and Usability of Various Robotic Arm Control Modes from Human Force Signals

    Directory of Open Access Journals (Sweden)

    Sébastien Mick

    2017-10-01

    Full Text Available Elaborating an efficient and usable mapping between input commands and output movements is still a key challenge for the design of robotic arm prostheses. In order to address this issue, we present and compare three different control modes, by assessing them in terms of performance as well as general usability. Using an isometric force transducer as the command device, these modes convert the force input signal into either a position or a velocity vector, whose magnitude is linearly or quadratically related to force input magnitude. With the robotic arm from the open source 3D-printed Poppy Humanoid platform simulating a mobile prosthesis, an experiment was carried out with eighteen able-bodied subjects performing a 3-D target-reaching task using each of the three modes. The subjects were given questionnaires to evaluate the quality of their experience with each mode, providing an assessment of their global usability in the context of the task. According to performance metrics and questionnaire results, velocity control modes were found to perform better than position control mode in terms of accuracy and quality of control as well as user satisfaction and comfort. Subjects also seemed to favor quadratic velocity control over linear (proportional velocity control, even if these two modes did not clearly distinguish from one another when it comes to performance and usability assessment. These results highlight the need to take into account user experience as one of the key criteria for the design of control modes intended to operate limb prostheses.

  16. design of a decoupler controller for forced circulation evaporator used in a radioactive treatment plant

    International Nuclear Information System (INIS)

    Abdel-Halim, H.A.

    2005-01-01

    evaporation is a proven method for a treatment of liquid radioactive wastes providing both good decontamination and high concentration . in a radioactive waste treatment plant, an evaporator is used to reduce the volume of medium radioactive liquid waste arising from different applications of nuclear industries. the control system objective is to limit the composition of the liquid waste at a prescribed value. for the safe operation, without damaging the installed equipment, a good control for the evaporator operating pressure and the level of liquid waste inside the separator part has been required. evaporator equipment is a complex process, which is a multivariable, nonlinear and has many disturbances. therefore, design a control strategy for the evaporator is bit difficult. the solution method is based on system decoupling eliminating the parasite interactions between input-output pairing variables and converting multi-inputs multi-outputs (MIMO) system to several single-inputs single-outputs (SISO) systems

  17. Characterization of sliders for efficient force generation of electrostatically controlled linear actuator

    International Nuclear Information System (INIS)

    Nguyen, T A; Konishi, S

    2014-01-01

    In this paper, the characterization of sliders for efficient force generation of an electrostatically controlled linear actuator (ECLIA) is investigated. The ECLIA consists of a piezoactuator (PZT), driving and holding electrodes, multiple sliders and a guide structure. The stepping motion of the sliders is driven by the PZT actuator via an electrostatic clutch mechanism. Thus, multiple sliders can achieve parallel, independent, precise motion, and a large stroke. Previous studies have indicated that the Si bulk slider and Si electrode created an air gap owing to the deformation of the Si electrode. Thus, the Si slider generated a low pushing force. In this study, we propose a fishbone structure mounted on a flexible slider to enhance the pushing force of the slider. The flexible slider, that can deform and fit into the Si electrode to reduce the air gap, results in highly efficient electrostatic-force generation. The fishbone structure improves the longitudinal stiffness of the flexible slider for high pushing-force generation. The results show that the pushing force created by the fishbone slider was three times greater than that of the conventional Si slider. The fishbone and flexible sliders exhibited a high performance for the ECLIA. (paper)

  18. Inertial shear forces and the use of centrifuges in gravity research. What is the proper control?

    NARCIS (Netherlands)

    Loon, van J.J.W.A.; Folgering, H.T.E.; Bouten, C.V.C.; Veldhuijzen, J.P.; Smit, T.H.

    2003-01-01

    Centrifuges are used for 1×g controls in space flight microgravity experiments and in ground based research. Using centrifugation as a tool to generate an Earth like acceleration introduces unwanted inertial shear forces to the sample. Depending on the centrifuge and the geometry of the experiment

  19. A Cost-Effective Atomic Force Microscope for Undergraduate Control Laboratories

    Science.gov (United States)

    Jones, C. N.; Goncalves, J.

    2010-01-01

    This paper presents a simple, cost-effective and robust atomic force microscope (AFM), which has been purposely designed and built for use as a teaching aid in undergraduate controls labs. The guiding design principle is to have all components be open and visible to the students, so the inner functioning of the microscope has been made clear to…

  20. Force-controlled robotic assembly processes of rigid and flexible objects methodologies and applications

    CERN Document Server

    Ghalyan, Ibrahim Fahad Jasim

    2016-01-01

    This book provides comprehensive and integrated approaches for rigid and flexible object assembly. It presents comparison studies with the available force-guided robotic processes and covers contact-state modeling, scheme control strategies, and position searching algorithms. Further, it includes experimental validations for different assembly situations, including those for the assembly of industrial parts taken from the automotive industry. .

  1. Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

    International Nuclear Information System (INIS)

    Abdoli, A; Mirzaee, I; Purmahmod, N; Anvari, A

    2008-01-01

    Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s -1 at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A b and D c , have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications

  2. Simulation of body force field effects on airfoil separation control and optimization of plasma actuator

    Energy Technology Data Exchange (ETDEWEB)

    Abdoli, A; Mirzaee, I; Purmahmod, N [Faculty of Engineering, Urmia University, Urmia (Iran, Islamic Republic of); Anvari, A [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: ab.abdoli@gmail.com

    2008-09-07

    Among all active flow control methods, EHD, MHD and EMHD are the only methods which operate on the basis of body force induction on flow field. The EHD plasma actuator is the proper method which has been used in various flow control applications recently. In this paper, the effects of different body force fields on different domains have been studied for separation control on NACA 0021 and the results have been discussed. The airflow velocity has been assumed to be 35 m s{sup -1} at a post-stall angle of attack of 23 deg. Three different domains have been used around the airfoil to investigate body forces with different strengths and directions and those which give the best result in separation control have been obtained for each domain. It has been shown that the results could be used for optimizing the plasma actuator by manipulating its electrode configuration. Two non-dimensional numbers, A{sub b} and D{sub c}, have been obtained and validated by different applied body forces. These numbers have been defined for plasma actuators to show their efficiency in different applications.

  3. Quality control program of multi-leaf collimation based EPID for teams with Rapidarc

    International Nuclear Information System (INIS)

    Pujades Claumarchirant, M. C.; Richart Sancho, J.; Gimeno Olmos, J.; Lliso Valverde, F.; Carmona Mesenguer, V.; Garcia Martinez, M. T.; Palomo Llinares, R.; Ballester Pallares, F.; Perez Calatayud, J.

    2013-01-01

    The objective of this work is to show a collection of different recommendations on the control of quality of collimation multi-leaf system and present the selection of tests based on the electronic imaging device (EPID) portal that have decided to establish in our Center, where in addition to the requirements of quality assurance generic for collimation multi-leaf system quality control methods have been included for RapidArc. (Author)

  4. A Novel Approach for Automatic Control of Piezoelectric Elements Used for Lorentz Force Detuning Compensation

    CERN Document Server

    Przygoda, K; Napieralski, A; Grecki, M

    2010-01-01

    Abstract: Linear accelerators such as Free Electron Lasers (FELs) use superconducting (SC) resonant cavities to accelerate electron beam to high energies. TESLA type resonators are extremely sensitive to detuning induced by mechanical deformations – Lorentz force detuning (LFD), mainly due to the extremely high quality factor (Q) of the 1.3 GHz resonance mode, in the range of 1e6. The resulting modulation of a resonance frequency of the cavity makes power consumption and stability performances of the Low-Latency Radio Frequency (LLRF) control more critical. In order to minimize the RF control efforts and desired stabilities, the fast piezoelectric actuators with digital control systems are commonly used. The paper presents a novel approach for automatic control of piezoelectric actuators used for compensation of Lorentz force detuning, the practical application and carried out tests in accelerating module ACC6 in Free-Electron Laser in Hamburg (FLASH).

  5. Free and Forced Vibrations of an Axially-Loaded Timoshenko Multi-Span Beam Carrying a Number of Various Concentrated Elements

    Directory of Open Access Journals (Sweden)

    Yusuf Yesilce

    2012-01-01

    Full Text Available In the existing reports regarding free and forced vibrations of the beams, most of them studied a uniform beam carrying various concentrated elements using Bernoulli-Euler Beam Theory (BET but without axial force. The purpose of this paper is to utilize the numerical assembly technique to determine the exact frequency-response amplitudes of the axially-loaded Timoshenko multi-span beam carrying a number of various concentrated elements (including point masses, rotary inertias, linear springs and rotational springs and subjected to a harmonic concentrated force and the exact natural frequencies and mode shapes of the beam for the free vibration analysis. The model allows analyzing the influence of the shear and axial force and harmonic concentrated force effects and intermediate concentrated elements on the dynamic behavior of the beams by using Timoshenko Beam Theory (TBT. At first, the coefficient matrices for the intermediate concentrated elements, an intermediate pinned support, applied harmonic force, left-end support and right-end support of Timoshenko beam are derived. After the derivation of the coefficient matrices, the numerical assembly technique is used to establish the overall coefficient matrix for the whole vibrating system. Finally, solving the equations associated with the last overall coefficient matrix one determines the exact dynamic response amplitudes of the forced vibrating system corresponding to each specified exciting frequency of the harmonic force. Equating the determinant of the overall coefficient matrix to zero one determines the natural frequencies of the free vibrating system (the case of zero harmonic force and substituting the corresponding values of integration constants into the related eigenfunctions one determines the associated mode shapes. The calculated vibration amplitudes of the forced vibrating systems and the natural frequencies of the free vibrating systems are given in tables for different values of

  6. Multi-model-based Access Control in Construction Projects

    Directory of Open Access Journals (Sweden)

    Frank Hilbert

    2012-04-01

    Full Text Available During the execution of large scale construction projects performed by Virtual Organizations (VO, relatively complex technical models have to be exchanged between the VO members. For linking the trade and transfer of these models, a so-called multi-model container format was developed. Considering the different skills and tasks of the involved partners, it is not necessary for them to know all the models in every technical detailing. Furthermore, the model size can lead to a delay in communication. In this paper an approach is presented for defining model cut-outs according to the current project context. Dynamic dependencies to the project context as well as static dependencies on the organizational structure are mapped in a context-sensitive rule. As a result, an approach for dynamic filtering of multi-models is obtained which ensures, together with a filtering service, that the involved VO members get a simplified view of complex multi-models as well as sufficient permissions depending on their tasks.

  7. Collaborative-Hybrid Multi-Layer Network Control for Emerging Cyber-Infrastructures

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, Tom [USC; Ghani, Nasir [UNM; Boyd, Eric [UCAID

    2010-08-31

    At a high level, there were four basic task areas identified for the Hybrid-MLN project. They are: o Multi-Layer, Multi-Domain, Control Plane Architecture and Implementation, including OSCARS layer2 and InterDomain Adaptation, Integration of LambdaStation and Terapaths with Layer2 dynamic provisioning, Control plane software release, Scheduling, AAA, security architecture, Network Virtualization architecture, Multi-Layer Network Architecture Framework Definition; o Heterogeneous DataPlane Testing; o Simulation; o Project Publications, Reports, and Presentations.

  8. Influences of load characteristics on impaired control of grip forces in patients with cerebellar damage.

    Science.gov (United States)

    Brandauer, B; Timmann, D; Häusler, A; Hermsdörfer, J

    2010-02-01

    Various studies showed a clear impairment of cerebellar patients to modulate grip force in anticipation of the loads resulting from movements with a grasped object. This failure corroborated the theory of internal feedforward models in the cerebellum. Cerebellar damage also impairs the coordination of multiple-joint movements and this has been related to deficient prediction and compensation of movement-induced torques. To study the effects of disturbed torque control on feedforward grip-force control, two self-generated load conditions with different demands on torque control-one with movement-induced and the other with isometrically generated load changes-were directly compared in patients with cerebellar degeneration. Furthermore the cerebellum is thought to be more involved in grip-force adjustment to self-generated loads than to externally generated loads. Consequently, an additional condition with externally generated loads was introduced to further test this hypothesis. Analysis of 23 patients with degenerative cerebellar damage revealed clear impairments in predictive feedforward mechanisms in the control of both self-generated load types. Besides feedforward control, the cerebellar damage also affected more reactive responses when the externally generated load destabilized the grip, although this impairment may vary with the type of load as suggested by control experiments. The present findings provide further support that the cerebellum plays a major role in predictive control mechanisms. However, this impact of the cerebellum does not strongly depend on the nature of the load and the specific internal forward model. Contributions to reactive (grip force) control are not negligible, but seem to be dependent on the physical characteristics of an externally generated load.

  9. Comparative Effects of Different Balance-Training-Progression Styles on Postural Control and Ankle Force Production: A Randomized Controlled Trial.

    Science.gov (United States)

    Cuğ, Mutlu; Duncan, Ashley; Wikstrom, Erik

    2016-02-01

    Despite the effectiveness of balance training, the exact parameters needed to maximize the benefits of such programs remain unknown. One such factor is how individuals should progress to higher levels of task difficulty within a balance-training program. Yet no investigators have directly compared different balance-training-progression styles. To compare an error-based progression (ie, advance when proficient at a task) with a repetition-based progression (ie, advance after a set amount of repetitions) style during a balance-training program in healthy individuals. Randomized controlled trial. Research laboratory. A total of 28 (16 women, 12 men) physically healthy young adults (age = 21.57 ± 3.95 years, height = 171.60 ± 11.03 cm, weight = 72.96 ± 16.18 kg, body mass index = 24.53 ± 3.7). All participants completed 12 supervised balance-training sessions over 4 weeks. Each session consisted of a combination of dynamic unstable-surface tasks that incorporated a BOSU ball and lasted about 30 minutes. Static balance from an instrumented force plate, dynamic balance as measured via the Star Excursion Balance Test, and ankle force production in all 4 cardinal planes of motion as measured with a handheld dynamometer before and after the intervention. Selected static postural-control outcomes, dynamic postural control, and ankle force production in all planes of motion improved (P .05) for any of the outcome measures. A 4-week balance-training program consisting of dynamic unstable-surface exercises on a BOSU ball improved dynamic postural control and ankle force production in healthy young adults. These results suggest that an error-based balance-training program is comparable with but not superior to a repetition-based balance-training program in improving postural control and ankle force production in healthy young adults.

  10. Preliminary Experimental Results for Indirect Vector-Control of Induction Motor Drives with Forced Dynamics

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2003-01-01

    Full Text Available The contribution presents an extension of indirect vector control of electric drives employing induction motors to 'Forced Dynamic Control'. This method of control offers an accurate realisation of dynamic response profiles, which can be selected by the user. The developed system can be integrated into a drive with a shaft position encoder or a shaft sensoriess drive, in which only the stator currents are measured. The applied stator voltages are determined by a computed inverter switching algorithm. Simulation results and preliminary experimental results for indirect vector control of an idle running induction motor indicate good agreement with the theoretical predictions.

  11. Evaluation of friction forces between control bars and guide tubes of CAREM fuel element

    International Nuclear Information System (INIS)

    Ghiselli, Alberto M.; Fiori, Jose M.; Yedros, Pablo A.

    2003-01-01

    The design of the MSAC (Mecanismo del Sistema de ajuste y control, Mechanism of the Adjustment and control system, MACS) for CAREM reactor shall consider all loads that the reactor shall support during its operation. Several charges are originated by friction forces produced on contact points of the control Bars/Guide tubes assembly against other components. A test facility was designed and manufactured for the determination of friction components and the damping characteristics of the assembly formed by guide tubes fuel element, the control bars and the guide of the bar of the MACS. In this work a description of the test performed and the results obtained is presented. (author)

  12. Controlled, cross-sectional, multi-center study of physical capacity and associated factors in women with fibromyalgia.

    Science.gov (United States)

    Larsson, Anette; Palstam, Annie; Bjersing, Jan; Löfgren, Monika; Ernberg, Malin; Kosek, Eva; Gerdle, Björn; Mannerkorpi, Kaisa

    2018-04-19

    Health and physical capacity are commonly associated with disease, age, and socioeconomic factors. The primary objective of this study was to investigate the degree to which physical capacity, defined as muscle strength and walking ability, is decreased in women with fibromyalgia (FM), as compared to healthy women, who are matched for age and level of education. The secondary aim was to investigate whether muscle strength and walking ability are associated with age, symptom duration, activity limitations and, Body Mass Index (BMI) in women with FM and control subjects. This controlled, cross-sectional, multi-center study comprised 118 women with FM and 93 age- and education-level-matched healthy women. The outcome measures were isometric knee-extension force, isometric elbow-flexion force, isometric hand-grip force, and walking ability. Differences between the groups were calculated, and for the women with FM analyses of correlations between the measures of physical capacity and variables were performed. The women with FM showed 20% (p BMI. It seems important to address this problem and to target interventions to prevent decline in muscle strength. Assessments of muscle strength and walking ability are easy to administer and should be routinely carried out in the clinical setting for women with FM. ClinicalTrials.gov identification number: NCT01226784 , Oct 21, 2010.

  13. Robust Clamping Force Control of an Electro-Mechanical Brake System for Application to Commercial City Buses

    Directory of Open Access Journals (Sweden)

    Sangjune Eum

    2017-02-01

    Full Text Available This paper proposes a sensor-less robust force control method for improving the control performance of an electro-mechanical brake (EMB which is applicable to commercial city buses. The EMB generates the accurate clamping force commanded by a driver through an independent motor control at each wheel instead of using existing mechanical components. In general, an EMB undergoes parameter variation and a backdrivability problem. For this reason, the cascade control strategy (e.g., force-position cascade control structure is proposed and the disturbance observer is employed to enhance control robustness against model variations. Additionally, this paper proposed the clamping force estimation method for a sensor-less control, i.e., the clamping force observer (CFO. Finally, in order to confirm the performance and effectiveness of a proposed robust control method, several experiments are performed and analyzed.

  14. Displacement and force coupling control design for automotive active front steering system

    Science.gov (United States)

    Zhao, Wanzhong; Zhang, Han; Li, Yijun

    2018-06-01

    A displacement and force coupling control design for active front steering (AFS) system of vehicle is proposed in this paper. In order to investigate the displacement and force characteristics of the AFS system of the vehicle, the models of AFS system, vehicle, tire as well as the driver model are introduced. Then, considering the nonlinear characteristics of the tire force and external disturbance, a robust yaw rate control method is designed by applying a steering motor to generate an active steering angle to adjust the yaw stability of the vehicle. Based on mixed H2/H∞ control, the system robustness and yaw rate tracking performance are enforced by H∞ norm constraint and the control effort is captured through H2 norm. In addition, based on the AFS system, a planetary gear set and an assist motor are both added to realize the road feeling control in this paper to dismiss the influence of extra steering angle through a compensating method. Evaluation of the overall system is accomplished by simulations and experiments under various driving condition. The simulation and experiment results show the proposed control system has excellent tracking performance and road feeling performance, which can improve the cornering stability and maneuverability of vehicle.

  15. A 3D Printed Linear Pneumatic Actuator for Position, Force and Impedance Control

    Directory of Open Access Journals (Sweden)

    Jeremy Krause

    2018-05-01

    Full Text Available Although 3D printing has the potential to provide greater customization and to reduce the costs of creating actuators for industrial applications, the 3D printing of actuators is still a relatively new concept. We have developed a pneumatic actuator with 3D-printed parts and placed sensors for position and force control. So far, 3D printing has been used to create pneumatic actuators of the bellows type, thus having a limited travel distance, utilizing low pressures for actuation and being capable of only limited force production and response rates. In contrast, our actuator is linear with a large travel distance and operating at a relatively higher pressure, thus providing great forces and response rates, and this the main novelty of the work. We demonstrate solutions to key challenges that arise during the design and fabrication of 3D-printed linear actuators. These include: (1 the strategic use of metallic parts in high stress areas (i.e., the piston rod; (2 post-processing of the inner surface of the cylinder for smooth finish; (3 piston head design and seal placement for strong and leak-proof action; and (4 sensor choice and placement for position and force control. A permanent magnet placed in the piston head is detected using Hall effect sensors placed along the length of the cylinder to measure the position, and pressure sensors placed at the supply ports were used for force measurement. We demonstrate the actuator performing position, force and impedance control. Our work has the potential to open new avenues for creating less expensive, customizable and capable actuators for industrial and other applications.

  16. Intelligent computational control of multi-fingered dexterous robotic hand

    OpenAIRE

    Chen, Disi; Li, Gongfa; Jiang, Guozhang; Fang, Yinfeng; Ju, Zhaojie; Liu, Honghai

    2015-01-01

    We discuss the intelligent computational control theory and introduce the hardware structure of HIT/DLR II dexterous robotic hand, which is the typical dexterous robotic hand. We show that how DSP or FPGA controller can be used in the dexterous robotic hand. A popular intelligent dexterous robotic hand control system, which named Electromyography (EMG) control is investigated. We introduced some mathematical algorithms in EMG controlling, such as Gauss mixture model (GMM), artificial neural n...

  17. Systematic Integrated Process Design and Control of Reactive Distillation Processes Involving Multi-elements

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil; Sales-Cruz, Mauricio; Huusom, Jakob Kjøbsted

    2016-01-01

    driving force approach. Next, through analytical, steady-state and closed-loop dynamic analysis it is verified that the control structure, disturbance rejection and energy requirement of the reactive distillation column is better than any other operation point that is not at the maximum driving force...

  18. Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter

    Directory of Open Access Journals (Sweden)

    Nobutomo Morita

    2018-01-01

    Full Text Available The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces—such as metal, paper, film, and so on—thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV by modifying the design which was adopted from MEMS (microelectromechanical systems fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects—aluminum block, wood block, and white acrylic block—considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

  19. Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter.

    Science.gov (United States)

    Morita, Nobutomo; Nogami, Hirofumi; Higurashi, Eiji; Sawada, Renshi

    2018-01-23

    The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV) and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces-such as metal, paper, film, and so on-thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV) by modifying the design which was adopted from MEMS (microelectromechanical systems) fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects-aluminum block, wood block, and white acrylic block-considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

  20. MultiController: the PLC-SCADA object for advanced regulation

    CERN Document Server

    Ortola, J

    2007-01-01

    Nowadays, industrial solutions with PLCs (Programmable Logic Controllers) have basic control loop features. The SCADA (Supervisory Control And Data Acquisition) system is a key point of the process control system due to an efficient HMI (Human Machine Interfaces) that provides an open method of tuning and leading possibilities. As a consequence, advanced control algorithms have to be developed and implemented for those PLC-SCADA solutions in order to provide perspectives in solving complex and critical regulation problems. The MultiController is an object integrated for a large scale project at CERN (the European Organization for Nuclear Research) named LHC-GCS (Large Hadron Collider - Gas Control System). It is developed for a Framework called CERN-UNICOS based on PLC-SCADA facilities. The MultiController object offers various advanced control loop strategies. It gives to the user advanced control algorithms like PID, Smith Predictor, PFC, GPC and RST. It is implemented as a monolithic entity (in PLC and SCA...

  1. Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs

    Science.gov (United States)

    Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

    2017-07-01

    In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

  2. Integral force feedback control with input shaping: Application to piezo-based scanning systems in ECDLs.

    Science.gov (United States)

    Zhang, Meng; Liu, Zhigang; Zhu, Yu; Bu, Mingfan; Hong, Jun

    2017-07-01

    In this paper, a hybrid control system is developed by integrating the closed-loop force feedback and input shaping method to overcome the problem of the hysteresis and dynamic behavior in piezo-based scanning systems and increase the scanning speed of tunable external cavity diode lasers. The flexible hinge and piezoelectric actuators are analyzed, and a dynamic model of the scanning systems is established. A force sensor and an integral controller are utilized in integral force feedback (IFF) to directly augment the damping of the piezoelectric scanning systems. Hysteresis has been effectively eliminated, but the mechanical resonance is still evident. Noticeable residual vibration occurred after the inflection points and then gradually disappeared. For the further control of mechanical resonance, based on the theory of minimum-acceleration trajectory planning, the time-domain input shaping method was developed. The turning sections of a scanning trajectory are replaced by smooth curves, while the linear sections are retained. The IFF method is combined with the input shaping method to control the non-linearity and mechanical resonance in high-speed piezo-based scanning systems. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

  3. A Droop Line Tracking Control for Multi-terminal VSC-HVDC Transmission System

    DEFF Research Database (Denmark)

    Irnawan, Roni; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2018-01-01

    Generally, a voltage-sourced converter (VSC) within a multi-terminal HVDC (MTDC) system can be operated either in constant DC voltage, constant flow (AC active power or DC current) or DC voltage droop control. These control modes can be easily represented as the droop characteristic line with dif......Generally, a voltage-sourced converter (VSC) within a multi-terminal HVDC (MTDC) system can be operated either in constant DC voltage, constant flow (AC active power or DC current) or DC voltage droop control. These control modes can be easily represented as the droop characteristic line...

  4. HapTip: Displaying Haptic Shear Forces at the Fingertips for Multi-Finger Interaction in Virtual Environments

    Directory of Open Access Journals (Sweden)

    Adrien eGirard

    2016-04-01

    Full Text Available The fingertips are one of the most important and sensitive parts of our body.They are the first stimulated areas of the hand when we interact with our environment.Providing haptic feedback to the fingertips in virtual reality could thus drastically improve perception and interaction with virtual environments.In this paper, we present a modular approach called HapTip to display such haptic sensations at the level of the fingertips.This approach relies on a wearable and compact haptic device able to simulate 2 Degree of Freedom (DoF shear forces on the fingertip with a displacement range of +/- 2 mm. Several modules can be added and used jointly in order to address multi-finger and/or bimanual scenarios in virtual environments.For that purpose, we introduce several haptic rendering techniques to cover different cases of 3D interaction such as touching a rough virtual surface, or feeling the inertia or weight of a virtual object.In order to illustrate the possibilities offered by HapTip, we provide four use cases focused on touching or grasping virtual objects.To validate the efficiency of our approach, we also conducted experiments to assess the tactile perception obtained with HapTip.Our results show that participants can successfully discriminate the directions of the 2 DoF stimulation of our haptic device.We found also that participants could well perceive different weights of virtual objects simulated using two HapTip devices. We believe that HapTip could be used in numerous applications in virtual reality for which 3D manipulation and tactile sensations are often crucial, such as in virtual prototyping or virtual training.

  5. Force analysis of the advanced neutron source control rod drive latch mechanism

    International Nuclear Information System (INIS)

    Damiano, B.

    1989-01-01

    The Advanced Neutron Source reactor (ANS), a proposed Department of Energy research reactor currently undergoing conceptual design at the Oak Ridge National Laboratory (ORNL), will generate a thermal neutron flux approximating 10 30 M -2 emdash S -1 . The compact core necessary to produce this flux provides little space for the shim safety control rods, which are located in the central annulus of the core. Without proper control rod drive design, the control rod drive magnets (which hold the control rod latch in a ready-to-scram position) may be unable to support the required load due to their restricted size. This paper describes the force analysis performed on the control rod latch mechanism to determine the fraction of control rod weight transferred to the drive magnet. This information will be useful during latch, control rod drive and magnet design. 5 refs., 12 figs

  6. Managing Air Quality - Multi-Pollutant Planning and Control

    Science.gov (United States)

    Describes how planning controls for multiple pollutants at the same time can save money and time and achieve significant benefits, and how control strategies can address both climate change and air quality.

  7. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes

    International Nuclear Information System (INIS)

    Park, Hyungmin; Choi, Haecheon

    2012-01-01

    In the present study, we conduct an experiment using a one-paired dynamically scaled model of an insect wing, to investigate how asymmetric strokes with different wing kinematic parameters are used to control the aerodynamics of a dragonfly-like inclined flapping wing in still fluid. The kinematic parameters considered are the angles of attack during the mid-downstroke (α md ) and mid-upstroke (α mu ), and the duration (Δτ) and time of initiation (τ p ) of the pitching rotation. The present dragonfly-like inclined flapping wing has the aerodynamic mechanism of unsteady force generation similar to those of other insect wings in a horizontal stroke plane, but the detailed effect of the wing kinematics on the force control is different due to the asymmetric use of the angle of attack during the up- and downstrokes. For example, high α md and low α mu produces larger vertical force with less aerodynamic power, and low α md and high α mu is recommended for horizontal force (thrust) production. The pitching rotation also affects the aerodynamics of a flapping wing, but its dynamic rotational effect is much weaker than the effect from the kinematic change in the angle of attack caused by the pitching rotation. Thus, the influences of the duration and timing of pitching rotation for the present inclined flapping wing are found to be very different from those for a horizontal flapping wing. That is, for the inclined flapping motion, the advanced and delayed rotations produce smaller vertical forces than the symmetric one and the effect of pitching duration is very small. On the other hand, for a specific range of pitching rotation timing, delayed rotation requires less aerodynamic power than the symmetric rotation. As for the horizontal force, delayed rotation with low α md and high α mu is recommended for long-duration flight owing to its high efficiency, and advanced rotation should be employed for hovering flight for nearly zero horizontal force. The present

  8. Teleoperator comfort and psychometric stability: Criteria for limiting master-controller forces of operation and feedback during telemanipulation

    Science.gov (United States)

    Wiker, Steven F.; Hershkowitz, Elaine; Zik, John

    1989-01-01

    The following question is addressed: How much force should operators exert, or experience, when operating a telemanipulator master-controller for sustained periods without encountering significant fatigue and discomfort, and without loss of stability in psychometric perception of force. The need to minimize exertion demands to avoid fatigue is diametrically opposed by the need to present a wide range of force stimuli to enhance perception of applied or reflected forces. For 104 minutes subjects repetitiously performed a series of 15 s isometric pinch grasps; controlled at 5, 15, and 25 percent of their maximum voluntary strength. Cyclic pinch grasps were separated by rest intervals of 7.5 and 15 s. Upon completion of every 10 minute period, subjects interrupted grasping activities to gage the intensity of fatigue and discomfort in the hand and forearm using a cross-modal matching technique. A series of psychometric tests were then conducted to determine accuracy and stability in the subject's perception of force experienced. Results showed that onset of sensations of discomfort and fatigue were dependent upon the magnitude of grasp force, work/rest ratio, and progression of task. Declines in force magnitude estimation slopes, indicating a reduction in force perception sensitivity, occurred with increased grasp force when work/rest ratios were greater than 1.0. Specific recommendations for avoiding discomfort and shifts in force perception, by limiting pinch grasp force required for master-controller operation and range of force reflection or work/rest ratios, are provided.

  9. Highly-Integrated Hydraulic Smart Actuators and Smart Manifolds for High-Bandwidth Force Control

    Directory of Open Access Journals (Sweden)

    Victor Barasuol

    2018-06-01

    Full Text Available Hydraulic actuation is the most widely used alternative to electric motors for legged robots and manipulators. It is often selected for its high power density, robustness and high-bandwidth control performance that allows the implementation of force/impedance control. Force control is crucial for robots that are in contact with the environment, since it enables the implementation of active impedance and whole body control that can lead to a better performance in known and unknown environments. This paper presents the hydraulic Integrated Smart Actuator (ISA developed by Moog in collaboration with IIT, as well as smart manifolds for rotary hydraulic actuators. The ISA consists of an additive-manufactured body containing a hydraulic cylinder, servo valve, pressure/position/load/temperature sensing, overload protection and electronics for control and communication. The ISA v2 and ISA v5 have been specifically designed to fit into the legs of IIT’s hydraulic quadruped robots HyQ and HyQ-REAL, respectively. The key features of these components tackle 3 of today’s main challenges of hydraulic actuation for legged robots through: (1 built-in controllers running inside integrated electronics for high-performance control, (2 low-leakage servo valves for reduced energy losses, and (3 compactness thanks to metal additive manufacturing. The main contributions of this paper are the derivation of the representative dynamic models of these highly integrated hydraulic servo actuators, a control architecture that allows for high-bandwidth force control and their experimental validation with application-specific trajectories and tests. We believe that this is the first work that presents additive-manufactured, highly integrated hydraulic smart actuators for robotics.

  10. Comparison of timing and force control of foot tapping between elderly and young subjects.

    Science.gov (United States)

    Takimoto, Koji; Takebayashi, Hideaki; Miyamoto, Kenzo; Takuma, Yutaka; Inoue, Yoshikazu; Miyamoto, Shoko; Okabe, Takao; Okuda, Takahiro; Kaba, Hideto

    2016-06-01

    [Purpose] To examine the ability of young and elderly individuals to control the timing and force of periodic sequential foot tapping. [Subjects and Methods] Participants were 10 young (age, 22.1 ± 4.3 years) and 10 elderly individuals (74.8 ± 6.7 years) who were healthy and active. The foot tapping task consisted of practice (stimulus-synchronized tapping with visual feedback) and recall trials (self-paced tapping without visual feedback), periodically performed in this order, at 500-, 1,000-, and 2,000-ms target interstimulus-onset intervals, with a target force of 20% maximum voluntary contraction of the ankle plantar-flexor muscle. [Results] The coefficients of variation of force and intertap interval, used for quantifying the steadiness of the trials, were significantly greater in the elderly than in the young individuals. At the 500-ms interstimulus-onset interval, age-related effects were observed on the normalized mean absolute error of force, which was used to quantify the accuracy of the trials. The coefficients of variation of intertap interval for elderly individuals were significantly greater in the practice than in the recall trials at the 500- and 1,000-ms interstimulus-onset intervals. [Conclusion] The elderly individuals exhibited greater force and timing variability than the young individuals and showed impaired visuomotor processing during foot tapping sequences.

  11. Effective method to control the levitation force and levitation height in a superconducting maglev system

    International Nuclear Information System (INIS)

    Yang Peng-Tao; Yang Wan-Min; Wang Miao; Li Jia-Wei; Guo Yu-Xia

    2015-01-01

    The influence of the width of the middle magnet in the permanent magnet guideways (PMGs) on the levitation force and the levitation height of single-domain yttrium barium copper oxide (YBCO) bulks has been investigated at 77 K under the zero field cooled (ZFC) state. It is found that the largest levitation force can be obtained in the system with the width of the middle magnet of the PMG equal to the size of the YBCO bulk when the gap between the YBCO bulk and PMG is small. Both larger levitation force and higher levitation height can be obtained in the system with the width of the middle magnet of the PMG larger than the size of the YBCO bulk. The stiffness of the levitation force between the PMG and the YBCO bulk is higher in the system with a smaller width of the middle magnet in the PMG. These results provide an effective way to control the levitation force and the levitation height for the superconducting maglev design and applications. (paper)

  12. A Gradient Optimization Approach to Adaptive Multi-Robot Control

    Science.gov (United States)

    2009-09-01

    t) - v, (t) = 0 Vi from the first term in the sum, so the network converges to a near-optimal coverage configuration. Furthermore, from Ci(7) Td (t...they are not a function of 7) to get ry&(t)TW[j (TF)ICjIC[ d-l &di(t) = nYdcti( td Since 1V - 0, if limt,, Ai (t) is positive definite (we know the limit...property clearly, examine the magnitude of force exerted by one neighbor (m - 1 = 1) given by IIl f = 0ij - 02i/ llj - P I, and shown in the left of

  13. Proportional Derivative Active Force Control for “X” Configuration Quadcopter

    Directory of Open Access Journals (Sweden)

    Niam Tamami

    2014-12-01

    Full Text Available This paper present a control method “x” configuration quadcopter. The control method used PDAFC (Proportional Derivative Active Force Control. PD is used to stabilize quadcopter, and AFC is used to reject uncertainty disturbance (e.g. wind by estimate disturbance torque value of quadcopter. By adding PD with AFC, better result is obtained, AFC can minimize uncertainty disturbance effect. The sensitivity toward uncertainty disturbance can be set from sensitivity constant to get best performance of disturbance rejection. Stability analysis of PDAFC was evaluated by Lyapunov stability theory.

  14. Force Control for a Pneumatic Cylinder Using Generalized Predictive Controller Approach

    OpenAIRE

    Mohd Faudzi, Ahmad ’Athif; Mustafa, Nu’man Din; Osman, Khairuddin

    2014-01-01

    Pneumatic cylinder is a well-known device because of its high power to weight ratio, easy use, and environmental safety. Pneumatic cylinder uses air as its power source and converts it to a possible movement such as linear and rotary movement. In order to control the pneumatic cylinder, controller algorithm is needed to control the on-off solenoid valve with encoder and pressure sensor as the feedback inputs. In this paper, generalized predictive controller (GPC) is proposed as the control st...

  15. Analysis of the Usage of Magnetic Force-directed Approach and Visual Techniques for Interactive Context-based Drawing of Multi-attributed Graphs

    Directory of Open Access Journals (Sweden)

    Zabiniako Vitaly

    2014-12-01

    Full Text Available In this article, the authors perform an analysis in order to assess adaptation of magnetic force-directed algorithms for context-based information extraction from multi-attributed graphs during visualization sessions. Theoretic standings behind magnetic force-directed approach are stated together with review on how particular features of respective algorithms in combination with appropriate visual techniques are especially suitable for improved processing and presenting of knowledge that is captured in form of graphs. The complexity of retrieving multi-attributed information within the proposed approach is handled with dedicated tools, such as selective attraction of nodes to MFE (Magnetic Force Emitter based on search criteria, localization of POI (Point of Interest regions, graph node anchoring, etc. Implicit compatibility of aforementioned tools with interactive nature of data exploration is distinguished. Description of case study, based on bibliometric network analysis is given, which is followed by the review of existing related works in this field. Conclusions are made and further studies in the field of visualization of multi-attributed graphs are defined.

  16. Force control tasks with pure haptic feedback promote short-term focused attention.

    Science.gov (United States)

    Wang, Dangxiao; Zhang, Yuru; Yang, Xiaoxiao; Yang, Gaofeng; Yang, Yi

    2014-01-01

    Focused attention has great impact on our quality of life. Our learning, social skills and even happiness are closely intertwined with our capacity for focused attention. Attention promotion is replete with examples of training-induced increases in attention capability, most of which rely on visual and auditory stimulation. Pure haptic stimulation to increase attention capability is rarely found. We show that accurate force control tasks with pure haptic feedback enhance short-term focused attention. Participants were trained by a force control task in which information from visual and auditory channels was blocked, and only haptic feedback was provided. The trainees were asked to exert a target force within a pre-defined force tolerance for a specific duration. The tolerance was adaptively modified to different levels of difficulty to elicit full participant engagement. Three attention tests showed significant changes in different aspects of focused attention in participants who had been trained as compared with those who had not, thereby illustrating the role of haptic-based sensory-motor tasks in the promotion of short-term focused attention. The findings highlight the potential value of haptic stimuli in brain plasticity and serve as a new tool to extend existing computer games for cognitive enhancement.

  17. Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme

    Directory of Open Access Journals (Sweden)

    Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin

    2012-08-01

    Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words:  Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.

  18. Superposition of automatic and voluntary aspects of grip force control in humans during object manipulation.

    Directory of Open Access Journals (Sweden)

    Frederic Danion

    Full Text Available When moving grasped objects, people automatically modulate grip force (GF with movement-dependent load force (LF in order to prevent object slip. However, GF can also be modulated voluntarily as when squeezing an object. Here we investigated possible interactions between automatic and voluntary GF control. Participants were asked to generate horizontal cyclic movements (between 0.6 and 2.0 Hz of a hand-held object that was restrained by an elastic band such that the load force (LF reached a peak once per movement cycle, and to simultaneously squeeze the object at each movement reversal (i.e., twice per cycle. Participants also performed two control tasks in which they either only moved (between 0.6 and 2.0 Hz or squeezed (between 1.2 and 4.0 Hz the object. The extent to which GF modulation in the simultaneous task could be predicted from the two control tasks was assessed using power spectral analyses. At all frequencies, the GF power spectra from the simultaneous task exhibited two prominent components that occurred at the cycle frequency (ƒ and at twice this frequency (2ƒ, whereas the spectra from the movement and squeeze control task exhibited only single peaks at ƒ and 2ƒ, respectively. At lower frequencies, the magnitudes of both frequency components in the simultaneous task were similar to the magnitudes of the corresponding components in the control tasks. However, as frequency increased, the magnitudes of both components in the simultaneous task were greater than the magnitudes of the corresponding control task components. Moreover, the phase relationship between the ƒ components of GF and LF began to drift from the value observed in the movement control task. Overall these results suggest that, at lower movement frequencies, voluntary and automatic GF control processes operate at different hierarchical levels. Several mechanisms are discussed to account for interaction effects observed at higher movement frequencies.

  19. Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

    Directory of Open Access Journals (Sweden)

    Sakuma Y

    2006-01-01

    Full Text Available AbstractAn atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs. Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of site-controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.

  20. Multivariable H force/level control of the twin-roller strip caster

    International Nuclear Information System (INIS)

    Cavazos, A.; Edwards, J.B.

    2005-01-01

    Twin-roller steel strip casters may offer some advantages with respect to classical continuous casting hot rolling processes. Some works have reported control aspects of this process and although the process has been found to be highly interactive and non-linear, little or no attention has been given to its multivariable characteristics. The purpose of this work is to design a multivariable control capable of decoupling the system. This paper presents some important aspects of the strip caster modeling and reports the simulation results of the application of the multivariable H-optimal control for nominal performance to force/level control. Various controllers have been designed for different pool level heights and it is shown that they can decouple the system, allowing the application of PI decentralized controllers to considerably improve performance. (author)

  1. Multi-agent based distributed control architecture for microgrid energy management and optimization

    International Nuclear Information System (INIS)

    Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-01-01

    Highlights: • A new multi-agent based distributed control architecture for energy management. • Multi-agent coordination based on non-cooperative game theory. • A microgrid model comprised of renewable energy generation systems. • Performance comparison of distributed with conventional centralized control. - Abstract: Most energy management systems are based on a centralized controller that is difficult to satisfy criteria such as fault tolerance and adaptability. Therefore, a new multi-agent based distributed energy management system architecture is proposed in this paper. The distributed generation system is composed of several distributed energy resources and a group of loads. A multi-agent system based decentralized control architecture was developed in order to provide control for the complex energy management of the distributed generation system. Then, non-cooperative game theory was used for the multi-agent coordination in the system. The distributed generation system was assessed by simulation under renewable resource fluctuations, seasonal load demand and grid disturbances. The simulation results show that the implementation of the new energy management system proved to provide more robust and high performance controls than conventional centralized energy management systems.

  2. Robot Control Using UML and Multi-agent System

    Directory of Open Access Journals (Sweden)

    Ales Pavliska

    2003-02-01

    Full Text Available Increased industrialization and new markets have led to an accumulation of used technical consumer goods, which results in greater exploitation of raw materials, energy and landfill sites. In order to reduce the use of natural resources conserve precious energy and limit the increase in waste volume. The application of disassembly techniques is the first step towards this prevention of waste. These techniques form a reliable and clean approach: "noble" or high-graded recycling. This paper presents a multi agent system for disassembly process, which is implemented in a computer-aided application for supervising of the disassembling system: the Interactive Intelligent Interface for Disassembling System. Unified modeling language diagrams are used for an internal and external definition of the disassembling system.

  3. Computer control of a multi-link manipulator

    International Nuclear Information System (INIS)

    Holt, J.E.; Thiruarooran, C.

    1988-01-01

    The Central Electricity Generating Board has a requirement for a manipulator which can deploy to its work location around obstacles. A multilink manipulator has been designed for this purpose. A computer control system designed to ease manipulator operation is described. Using the control program, the manipulator may be deployed using just 2 joysticks. Experience in the use of the program with an inspection manipulator at Sizewell 'A' Nuclear Power Station is discussed. When used to control a manipulator of 9 hydraulically actuated degrees of freedom, a control accuracy of about 1.5% of full extension has been achieved. (author)

  4. Controlling engineering project changes for multi-unit, multi-site standardized nuclear power plants

    International Nuclear Information System (INIS)

    Randall, E.; Boddeker, G.; McGugin, H.; Strother, E.; Waggoner, G.

    1978-01-01

    Multibillioin dollar multiple nuclear power plant projects have numerous potential sources of engineering changes. The majority of these are internally generated changes, client generated changes, and changes from construction, procurement, other engineering organizations, and regulatory organizations. For multiunit, multisite projects, the use of a standardized design is cost effective. Engineering changes can then be controlled for a single standardized design, and the unit or site unique changes can be treated as deviations. Once an effective change procedure is established for change control of the standardized design, the same procedures can be used for control of unit or site unique changes

  5. L1 Adaptive Control Augmentation System with Application to the X-29 Lateral/Directional Dynamics: A Multi-Input Multi-Output Approach

    Science.gov (United States)

    Griffin, Brian Joseph; Burken, John J.; Xargay, Enric

    2010-01-01

    This paper presents an L(sub 1) adaptive control augmentation system design for multi-input multi-output nonlinear systems in the presence of unmatched uncertainties which may exhibit significant cross-coupling effects. A piecewise continuous adaptive law is adopted and extended for applicability to multi-input multi-output systems that explicitly compensates for dynamic cross-coupling. In addition, explicit use of high-fidelity actuator models are added to the L1 architecture to reduce uncertainties in the system. The L(sub 1) multi-input multi-output adaptive control architecture is applied to the X-29 lateral/directional dynamics and results are evaluated against a similar single-input single-output design approach.

  6. Controls on Arctic sea ice from first-year and multi-year survival rates

    Energy Technology Data Exchange (ETDEWEB)

    Hunke, Jes [Los Alamos National Laboratory

    2009-01-01

    The recent decrease in Arctic sea ice cover has transpired with a significant loss of multi year ice. The transition to an Arctic that is populated by thinner first year sea ice has important implications for future trends in area and volume. Here we develop a reduced model for Arctic sea ice with which we investigate how the survivability of first year and multi year ice control the mean state, variability, and trends in ice area and volume.

  7. MUMTI a Multi-User-Multi-Task-Interpreter for process-control applications with CAMAC

    International Nuclear Information System (INIS)

    Busse, E.; Degenhardt, K.H.; Eichner, H.U.; Tschammer, V.; Vidic, U.; Woletz, W.

    1977-02-01

    The interactive, interpretative programming-system MUMTI runs on PDP11-RSX11M/D-systems. Its main application fields are industrial and process-control applications. The MUMTI language is described in detail. (WB) [de

  8. Real-time changes in corticospinal excitability related to motor imagery of a force control task

    DEFF Research Database (Denmark)

    Tatemoto, Tsuyoshi; Tsuchiya, Junko; Numata, Atsuki

    2017-01-01

    Objective To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Methods Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion...... in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist...... in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion...

  9. Resonant passive–active vibration absorber with integrated force feedback control

    International Nuclear Information System (INIS)

    Høgsberg, Jan; Brodersen, Mark L; Krenk, Steen

    2016-01-01

    A general format of a two-terminal vibration absorber is constructed by placing a passive unit in series with a hybrid unit, composed of an active actuator in parallel with a second passive element. The displacement of the active actuator is controlled by an integrated feedback control with the difference in force between the two passive elements as input. This format allows passive and active contributions to be combined arbitrarily within the hybrid unit, which results in a versatile absorber format with guaranteed closed-loop stability. This is demonstrated for resonant absorbers with inertia realized passively by a mechanical inerter or actively by the integrated force feedback. Accurate calibration formulae are presented for two particular absorber configurations and the performance is subsequently demonstrated with respect to both equal modal damping and effective response reduction. (technical note)

  10. Optimal arm posture control and tendon traction forces of a coupled tendon-driven manipulator

    International Nuclear Information System (INIS)

    Ma, Shugen

    1997-01-01

    In this study, the optimum arm posture of a coupled tendon-driven multijoint manipulator arm (or CT Arm) at maximum payload output was derived and the corresponding tendon traction forces were also analyzed, during management of a heavy payload by the manipulator in a gravity environment. The CT Arm is special tendon traction transmission mechanism in which a pair of tendons used to drive a joint is pulled from base actuators via pulleys mounted on the base-side joints. This mechanism enables optimal utilization of the coupled drive function of tendon traction forces and thus enables the lightweight manipulator to exhibit large payload capability. The properties of the CT Arm mechanism are elucidated by the proposed optimal posture control scheme. Computer simulation was also executed to verify the validity of the proposed control scheme. (author)

  11. MUMTI a Multi-User-Multi-Task-Interpreter for process-control applications with CAMAC

    International Nuclear Information System (INIS)

    Busse, E.; Degenhardt, K.H.; Vidic, U.

    1980-10-01

    MUMTI is an interactive, interpretative programming system for industrial control and process control applications running on PDP11-RXS11M/D-systems. The number of users of the MUMTI-system is not limited as far as core memory and/or terminals are available. The implemented arithmetic facilities are similar to those of other interpreters. A detailed description of the programming of CAMAC systems is given in a second part. (WB)

  12. Second-Order Controllability of Multi-Agent Systems with Multiple Leaders

    International Nuclear Information System (INIS)

    Liu Bo; Han Xiao; Shi Yun-Tao; Su Hou-Sheng

    2016-01-01

    This paper proposes a new second-order continuous-time multi-agent model and analyzes the controllability of second-order multi-agent system with multiple leaders based on the asymmetric topology. This paper considers the more general case: velocity coupling topology is different from location coupling topology. Some sufficient and necessary conditions are presented for the controllability of the system with multiple leaders. In addition, the paper studies the controllability of the system with velocity damping gain. Simulation results are given to illustrate the correctness of theoretical results. (paper)

  13. Communication Dependent Control of Multi-Vehicle Formations

    Science.gov (United States)

    2016-05-11

    On Maximizing the Second Smallest Eigen- value of a State-Dependent Graph Laplacian,” IEEE Transactions on Au- tomatic Control, vol. 51, no. 1, pp...Collective Motion With Limited Communication,” IEEE Transactions on Au- tomatic Control, vol. 53, no. 3, pp. 706–719, 2008. [Online]. Available: http

  14. AN INTELLIGENT NEURO-FUZZY TERMINAL SLIDING MODE CONTROL METHOD WITH APPLICATION TO ATOMIC FORCE MICROSCOPE

    Directory of Open Access Journals (Sweden)

    Seied Yasser Nikoo

    2016-11-01

    Full Text Available In this paper, a neuro-fuzzy fast terminal sliding mode control method is proposed for controlling a class of nonlinear systems with bounded uncertainties and disturbances. In this method, a nonlinear terminal sliding surface is firstly designed. Then, this sliding surface is considered as input for an adaptive neuro-fuzzy inference system which is the main controller. A proportinal-integral-derivative controller is also used to asist the neuro-fuzzy controller in order to improve the performance of the system at the begining stage of control operation. In addition, bee algorithm is used in this paper to update the weights of neuro-fuzzy system as well as the parameters of the proportinal-integral-derivative controller. The proposed control scheme is simulated for vibration control in a model of atomic force microscope system and the results are compared with conventional sliding mode controllers. The simulation results show that the chattering effect in the proposed controller is decreased in comparison with the sliding mode and the terminal sliding mode controllers. Also, the method provides the advantages of fast convergence and low model dependency compared to the conventional methods.

  15. AFECS. multi-agent framework for experiment control systems

    Energy Technology Data Exchange (ETDEWEB)

    Gyurjyan, V; Abbott, D; Heyes, G; Jastrzembski, E; Timmer, C; Wolin, E [Jefferson Lab, 12000 Jefferson Ave. MS-12B3, Newport News, VA 23606 (United States)], E-mail: gurjyan@jlab.org

    2008-07-01

    AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC.

  16. AFECS. Multi-Agent Framework for Experiment Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Vardan Gyurjyan; David Abbott; William Heyes; Edward Jastrzembski; Carl Timmer; Elliott Wolin

    2008-01-23

    AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC.

  17. Multi-mode vibration control of piping system

    International Nuclear Information System (INIS)

    Minowa, Takeshi; Seto, Kazuto; Iiyama, Fumiya; Sodeyama, Hiroshi

    1999-01-01

    In this paper, dual dynamic absorbers are applied to the piping system in order to control the multiple vibration modes. ANSYS, which is one of the software based on FEM(finite element method), is used for the design of dual dynamic absorbers as well as for the determination of their optimum installing positions. The dual dynamic absorbers designed optimally for controlling the first three vibration modes perform just like a houde damper in higher frequency and have an effect on controlling higher modes. To use this advantage, three dual dynamic absorbers are installed in positions where they influence higher modes, and not only the first three modes of the piping system but also the extensive modes are controlled. Practical experimental study has also been carried out and it is shown that a dual dynamic absorber is suitable for controlling the vibration of the piping system. (author)

  18. AFECS. multi-agent framework for experiment control systems

    International Nuclear Information System (INIS)

    Gyurjyan, V; Abbott, D; Heyes, G; Jastrzembski, E; Timmer, C; Wolin, E

    2008-01-01

    AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC

  19. A Distributed Multi-agent Control System for Power Consumption in Buildings

    DEFF Research Database (Denmark)

    Kosek, Anna Magdalena; Gehrke, Oliver

    2012-01-01

    This paper presents a distributed controller for adjusting the electrical consumption of a residential building in response to an external power setpoint in Watts. The controller is based on a multi-agent system and has been implemented in JCSP. It is modularly built, capable of self-configuratio...

  20. Polarization control of multi-photon absorption under intermediate femtosecond laser field

    International Nuclear Information System (INIS)

    Cheng Wenjing; Liang Guo; Wu Ping; Liu Pei; Jia Tianqing; Sun Zhenrong; Zhang Shian

    2017-01-01

    It has been shown that the femtosecond laser polarization modulation is a very simple and well-established method to control the multi-photon absorption process by the light–matter interaction. Previous studies mainly focused on the multi-photon absorption control in the weak field. In this paper, we further explore the polarization control behavior of multi-photon absorption process in the intermediate femtosecond laser field. In the weak femtosecond laser field, the second-order perturbation theory can well describe the non-resonant two-photon absorption process. However, the higher order nonlinear effect (e.g., four-photon absorption) can occur in the intermediate femtosecond laser field, and thus it is necessary to establish new theoretical model to describe the multi-photon absorption process, which includes the two-photon and four-photon transitions. Here, we construct a fourth-order perturbation theory to study the polarization control behavior of this multi-photon absorption under the intermediate femtosecond laser field excitation, and our theoretical results show that the two-photon and four-photon excitation pathways can induce a coherent interference, while the coherent interference is constructive or destructive that depends on the femtosecond laser center frequency. Moreover, the two-photon and four-photon transitions have the different polarization control efficiency, and the four-photon absorption can obtain the higher polarization control efficiency. Thus, the polarization control efficiency of the whole excitation process can be increased or decreased by properly designing the femtosecond laser field intensity and laser center frequency. These studies can provide a clear physical picture for understanding and controlling the multi-photon absorption process in the intermediate femtosecond laser field, and also can provide a theoretical guidance for the future experimental realization. (paper)

  1. Command and Control Architectures for Autonomous Micro-Robotic Forces - FY-2000 Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Dudenhoeffer, Donald Dean

    2001-04-01

    Advances in Artificial Intelligence (AI) and micro-technologies will soon give rise to production of large-scale forces of autonomous micro-robots with systems of innate behaviors and with capabilities of self-organization and real world tasking. Such organizations have been compared to schools of fish, flocks of birds, herds of animals, swarms of insects, and military squadrons. While these systems are envisioned as maintaining a high degree of autonomy, it is important to understand the relationship of man with such machines. In moving from research studies to the practical deployment of large-scale numbers of robots, one of critical pieces that must be explored is the command and control architecture for humans to re-task and also inject global knowledge, experience, and intuition into the force. Tele-operation should not be the goal, but rather a level of adjustable autonomy and high-level control. If a herd of sheep is comparable to the collective of robots, then the human element is comparable to the shepherd pulling in strays and guiding the herd in the direction of greener pastures. This report addresses the issues and development of command and control for largescale numbers of autonomous robots deployed as a collective force.

  2. Force Plate Assessment of Quiet Standing Balance Control: Perspectives on Clinical Application within Stroke Rehabilitation

    Directory of Open Access Journals (Sweden)

    Avril Mansfield

    2015-01-01

    Full Text Available Assessment of balance control is essential to guide physical rehabilitation poststroke. However, current observational assessment tools available to physiotherapists provide limited information about underlying dyscontrol. This paper describes a force plate-based assessment of quiet standing balance control that we have implemented for individuals attending inpatient stroke rehabilitation. The assessment uses two force plates to measure location of ground reaction forces to maintain stability in quiet standing in five conditions (eyes open, eyes closed, standing symmetrically, and maximal loading on the less-affected and more-affected limbs. Measures of interest are variability of the centers of pressure under each foot and both feet combined, weight-bearing asymmetry, and correlation of center of pressure fluctuations between limbs. We present representative values for the above-mentioned measures and case examples to illustrate how the assessment can reveal patient-specific balance control problems and direct treatment. We identify limitations to our current assessment and recommendations for future research.

  3. The Effects of Age, Gender, and Hand on Force Control Capabilities of Healthy Adults.

    Science.gov (United States)

    Lee, Baekhee; Lee, Mina; Yoh, Myeung Sook; You, Heecheon; Park, Hyunji; Jung, Kihyo; Lee, Byung Hwa; Na, Duk L; Kim, Geon Ha

    2015-12-01

    The present study examined the effects of age (20s to 70s), gender (male and female), and hand (dominant and nondominant) on force control capabilities (FCCs) in four force control phases (initiation, development, maintenance, and termination). Normative data of FCCs by force control phase are needed for various populations in age and gender to identify a type of motor performance reduction and its severity. FCCs of 360 participants (30 for each combination of age group and gender) were measured using a finger dynamometer and quantified in terms of initiation time (IT), development time (DT), maintenance error (ME), and termination time (TT). Although gradual increases (1%~28%) by age were shown in IT, DT, and TT, a dramatic increase in ME was observed among participants in their 50s (26%), 60s (68%), and 70s (160%) compared to those in their 20s~40s. The most distinctive interaction effect of age and gender was found in ME out of the four FCC measures. Lastly, hand and its related interactions were not found significant. Normative FCC data were established for four age groups (20s~40s, 50s, 60s, and 70s) and gender. The normative FCC data can be used for evaluating an individual's motor performance, screening patients with brain disorders, and designing input devices triggered and/or operated by the finger. © 2015, Human Factors and Ergonomics Society.

  4. Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Huangqiu Zhu

    2015-05-01

    Full Text Available Bearingless permanent magnet synchronous motors (BPMSMs, with all advantages of permanent magnet motors (PMSMs and magnetic bearings, have become an important research direction in the bearingless motor field. To realize a stable suspension for the BPMSM, accurate decoupling control between the electromagnetic torque and radial suspension force is indispensable. In this paper, a concise and reliable analysis method based on a magnetic field equivalent current is presented. By this analysis method, the operation principle is analyzed theoretically, and the necessary conditions to produce a stable radial suspension force are confirmed. In addition, mathematical models of the torque and radial suspension force are established which is verified by the finite element analysis (FEA software ANSYS. Finally, an experimental prototype of a 2-4 poles surface-mounted BPMSM is tested with the customized control strategy. The simulation and experimental results have shown that the motor has good rotation and suspension performance, and validated the accuracy of the proposed analysis method and the feasibility of the control strategy.

  5. Multi-agent cooperation for particle accelerator control

    CERN Document Server

    Skarek, Paul

    1996-01-01

    We present practical investigations in a real industrial controls environment for justifying theoretical DAI (Distributed Artificial Intelligence) results, and we discuss theoretical aspects of practical investigations for accelerator control and operation. A generalized hypothesis is introduced based on a unified view of control, monitoring, diagnosis, maintenance and repair tasks leading to a general method of cooperation for expert systems by exchanging hypotheses. This has been tested for task and result sharing cooperation scenarios. Generalized hypotheses also allow us to treat the repetitive diagnosis-recovery cycle as task sharing cooperation. Problems with such a loop or even recursive calls between the different agents are discussed.

  6. Studies on the coordinated operation and autonomous control for multi-modular nuclear power plants

    International Nuclear Information System (INIS)

    Hui Chao; Huang Xiaojin; Wang Jie

    2011-01-01

    The tendency has always been to build ever larger single-modular reactor plants with the objective of benefiting from economies of scale. These plants have compiled admirable safety records. Nevertheless, there is concern that conventional large single reactors have become too complex by reason of placing too much reliance on engineered safeguards. The multi-modular approach offers a solution in that its use of many small reactors in conjunction with several shared turbines permits a simpler core design while, at the same time, at least partially retaining economies of scale by increasing the number of modules. Specific advantages to the multi-modular approach are as follows. First, the small-sized of the reactor core may allow the incorporation of passive safety features such as natural circulation cooling on loss of off-site electricity. Second, the individual modules are to be sized so that components related to nuclear safety can be factory-fabricated. Moreover, once the major components are made, they are to be transported to the site for rapid installation. This construction method is expected to reduce the licensing effort because the modules will be pre-licensed, and only site-specific issues will have to be considered in the final licensing process. At present, related studies show that the multi-modular approach for Generation IV can retain both the inherent safety and good economies of scale. However, the unbalanced load operation of the multi-modular power plant in which each module operates at a different power level and strong coupling between multi modules creates a complex control challenge to safe operation and control. Firstly, this paper summarizes the unbalanced load operation characteristics and challenges faced by operation and control of multi-modular power plant in the dynamic operational characteristics and requirements of coordinated control between multi modules. Secondly, detailed analysis and comparison are given in the integral

  7. Multi-technology control centre to integrate 460 MW renewables

    International Nuclear Information System (INIS)

    2016-01-01

    The new RWE Innogy Aersa Control Centre that has been certified to act as an interface with CECRE (the Renewable Energy Control Centre) since February 2015, connects RWE’s 20 renewable energy facilities with REE, the Spanish Electricity Grid. As a result, it ensures that wind farms, in addition to hydropower and solar plants, can inject the energy generated by its 460 MW installed safely and with no penalties. Green Eagle Solutions, a provider of software solutions for renewable energy companies, has collaborated with RWE in the development of this Control Centre, meeting the high standards of quality and safety required by RWE. This centre uses CompactSCADA® technology to integrate power generation facilities that need to be integrated in a Control Centre to communicate with REE’s CECRE. (Author)

  8. Electric Agricultural Robot with Multi-Layer-Control

    DEFF Research Database (Denmark)

    Griepentrog, Hans W.; Jæger-Hansen, Claes Lund; Dühring, Karina

    Research within agricultural technology focuses mainly on increasing the efficiency of crop production. Electric powered machines have several advantages. The machine control is much easier in terms of sensor integration, active navigation and task application compared with traditional machine ty...

  9. Controlling multi-bunches by a fast phase switching

    International Nuclear Information System (INIS)

    Decker, F.J.; Jobe, R.K.; Merminga, N.; Thompson, K.A.

    1990-09-01

    In linear accelerators with two or more bunches the beam loading of one bunch will influence the energy and energy spread the following bunches. This can be corrected by quickly changing the phase of a traveling wave-structure, so that each bunch receives a slightly different net phase. At the SLAC Linear Collider (SLC) three bunches, two (e + ,e - ) for the high energy collisions and one (e - -scavenger) for producing positrons should sit at different phases, due to their different tasks. The two e - -bunches are extracted from the damping ring at the same cycle time about 60 ns apart. Fast phase switching of the RF to the bunch length compressor in the Ring-To-Linac (RTL) section can produce the necessary advance of the scavenger bunch (about 6 degree in phase). This allows a low energy spread of this third bunch at the e + -production region at 2/3 of the linac length, while the other bunches are not influenced. The principles and possible other applications of this fast phase switching as using it for multi-bunches, as well as the experimental layout for the actual RTL compressor are presented

  10. Multi-channel control circuit for real-time control of events in Aditya tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Edappala, Praveenlal, E-mail: praveen@ipr.res.in; Shah, Minsha; Rajpal, Rachana; Tanna, R.L.; Ghosh, Joydeep; Chattopadhyay, P.K.; Jha, R.

    2016-11-15

    Highlights: • Low cost microcontroller based control circuit. • The control hardware can be programmed/configured very easily for different applications. • Microcontroller programming is done in assembly language so that precise timing can be achieved with micro seconds resolution. • Successful implementation of this circuit in noisy tokamak environment. • Efficient noise and burst elimination. • Can be integrated in to the other subsystems. • Low cost solution for implementing feedback control in small and medium size tokamaks and other experiments requiring feedback control. - Abstract: Tokamak plasma is prone to many random events having potential for causing severe damages to the machine, such as disruptions, production and elimination of high-energy runaway electrons etc. These events can be mitigated by obtaining pre-cursor signal leading to these events and then taking proper measures just before their onset to avoid their happenings, like disruptions can be mitigated by massive gas injection or putting a bias voltage on an electrode placed inside the plasma, the runaways can be mitigated by gas injection and by applying specific magnetic fields. Hence for real time control of these events, the pre-cursors should be electronically recorded and the mitigation techniques should be initiated by sending triggers to their individual operational systems. To implement these methodologies of real-time controlling of events in Aditya Tokamak, a low cost multi-channel Micro-Controller based timing circuit is designed and developed in-house. This circuit first compares the precursor signals fed into it with the pre-set values and gives a trigger output whenever the signals overshoot the pre-set values. The circuit readies itself for operation along with start of the tokamak discharge and waits up to an initial pre-determined delay and then initiates a trigger at the time of overshooting of precursor signal. The circuit is fully integrated and assembled in

  11. Explicit/multi-parametric model predictive control (MPC) of linear discrete-time systems by dynamic and multi-parametric programming

    KAUST Repository

    Kouramas, K.I.

    2011-08-01

    This work presents a new algorithm for solving the explicit/multi- parametric model predictive control (or mp-MPC) problem for linear, time-invariant discrete-time systems, based on dynamic programming and multi-parametric programming techniques. The algorithm features two key steps: (i) a dynamic programming step, in which the mp-MPC problem is decomposed into a set of smaller subproblems in which only the current control, state variables, and constraints are considered, and (ii) a multi-parametric programming step, in which each subproblem is solved as a convex multi-parametric programming problem, to derive the control variables as an explicit function of the states. The key feature of the proposed method is that it overcomes potential limitations of previous methods for solving multi-parametric programming problems with dynamic programming, such as the need for global optimization for each subproblem of the dynamic programming step. © 2011 Elsevier Ltd. All rights reserved.

  12. Parabolized Stability Equations analysis of nonlinear interactions with forced eigenmodes to control subsonic jet instabilities

    International Nuclear Information System (INIS)

    Itasse, Maxime; Brazier, Jean-Philippe; Léon, Olivier; Casalis, Grégoire

    2015-01-01

    Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m 1 , n 1 ), (m 2 , n 2 ), such that the difference in azimuth and in frequency matches the desired “target” mode (m 1 − m 2 , n 1 − n 2 ). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes

  13. A moving control volume method for smooth computation of hydrodynamic forces and torques on immersed bodies

    Science.gov (United States)

    Nangia, Nishant; Patankar, Neelesh A.; Bhalla, Amneet P. S.

    2017-11-01

    Fictitious domain methods for simulating fluid-structure interaction (FSI) have been gaining popularity in the past few decades because of their robustness in handling arbitrarily moving bodies. Often the transient net hydrodynamic forces and torques on the body are desired quantities for these types of simulations. In past studies using immersed boundary (IB) methods, force measurements are contaminated with spurious oscillations due to evaluation of possibly discontinuous spatial velocity of pressure gradients within or on the surface of the body. Based on an application of the Reynolds transport theorem, we present a moving control volume (CV) approach to computing the net forces and torques on a moving body immersed in a fluid. The approach is shown to be accurate for a wide array of FSI problems, including flow past stationary and moving objects, Stokes flow, and high Reynolds number free-swimming. The approach only requires far-field (smooth) velocity and pressure information, thereby suppressing spurious force oscillations and eliminating the need for any filtering. The proposed moving CV method is not limited to a specific IB method and is straightforward to implement within an existing parallel FSI simulation software. This work is supported by NSF (Award Numbers SI2-SSI-1450374, SI2-SSI-1450327, and DGE-1324585), the US Department of Energy, Office of Science, ASCR (Award Number DE-AC02-05CH11231), and NIH (Award Number HL117163).

  14. Enhancing the control of force in putting by video game training.

    Science.gov (United States)

    Fery, Y A; Ponserre, S

    2001-10-10

    Even if golf video games provide no proprioceptive afferences on actual putting movement, they may give sufficient substitutive visual cues to enhance force control in this skill. It was hypothesized that this usefulness requires, however, two conditions: the video game must provide reliable demonstrations of actual putts, and the user must want to use the game to make progress in actual putting. Accordingly, a video game was selected on the basis of its fidelity to the real-world game. It allowed two different methods of adjusting the virtual player's putting force in order to hole a putt: an analogue method that consisted of focusing on the virtual player's movement and a symbolic method that consisted of focusing on the movement of a gauge on a scale representing the virtual player's putting force. The participants had to use one of these methods with either the intention of making progress in actual putting or in a second condition to simply enjoy the game. Results showed a positive transfer of video playing to actual putting skill for the learning group and also, to a lesser degree, for the enjoyment group; but only when they used the symbolic method. Results are discussed in the context of how vision may convey force cues in sports video games.

  15. A positional code and anisotropic forces control tissue remodeling in Drosophila

    Science.gov (United States)

    Zallen, Jennifer

    A major challenge in developmental biology is to understand how tissue-scale changes in organism structure arise from events that occur on a cellular and molecular level. We are using cell biological, biophysical, and quantitative live-embryo imaging approaches to understand how genes encode the forces that shape tissues, and to identify the mechanisms that modulate cell behavior in response to local forces. In many animals, the elongated head-to-tail body axis is achieved by rapid and coordinated movements of hundreds of cells. We found that in the fruit fly, these cell movements are regulated by subcellular asymmetries in the localization of proteins that generate contractile and adhesive forces between cells. Asymmetries in the force-generating machinery are in turn controlled by a positional code of spatial information provided by an ancient family of Toll-related receptors that are widely used for pathogen recognition by the innate immune system. I will describe how this spatial system systematically orients local cell movements and collective rosette-like clusters in the Drosophila embryo. Rosettes have now also been shown to shape the body axis in chicks, frogs, and mice, demonstrating that rosette behaviors are a general mechanism linking cellular asymmetry to tissue reorganization.

  16. Parabolized Stability Equations analysis of nonlinear interactions with forced eigenmodes to control subsonic jet instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Itasse, Maxime, E-mail: Maxime.Itasse@onera.fr; Brazier, Jean-Philippe, E-mail: Jean-Philippe.Brazier@onera.fr; Léon, Olivier, E-mail: Olivier.Leon@onera.fr; Casalis, Grégoire, E-mail: Gregoire.Casalis@onera.fr [Onera - The French Aerospace Lab, F-31055 Toulouse (France)

    2015-08-15

    Nonlinear evolution of disturbances in an axisymmetric, high subsonic, high Reynolds number hot jet with forced eigenmodes is studied using the Parabolized Stability Equations (PSE) approach to understand how modes interact with one another. Both frequency and azimuthal harmonic interactions are analyzed by setting up one or two modes at higher initial amplitudes and various phases. While single mode excitation leads to harmonic growth and jet noise amplification, controlling the evolution of a specific mode has been made possible by forcing two modes (m{sub 1}, n{sub 1}), (m{sub 2}, n{sub 2}), such that the difference in azimuth and in frequency matches the desired “target” mode (m{sub 1} − m{sub 2}, n{sub 1} − n{sub 2}). A careful setup of the initial amplitudes and phases of the forced modes, defined as the “killer” modes, has allowed the minimizing of the initially dominant instability in the near pressure field, as well as its estimated radiated noise with a 15 dB loss. Although an increase of the overall sound pressure has been found in the range of azimuth and frequency analyzed, the present paper reveals the possibility to make the initially dominant instability ineffective acoustically using nonlinear interactions with forced eigenmodes.

  17. Feedback control and adaptive synchronization of chaotic forced Bonhoeffer-van der Pol oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Kontchou, E W Chimi; Fotsin, H B [Laboratoire d' Electronique, Departement de Physique, Faculte des Sciences, Universite de Dschang, B P 67 Dschang (Cameroon); Woafo, P [Laboratory of Modelling and Simulation in Engineering and Biological Physics, Faculty of Science, University of Yaounde I, Box 812, Yaounde (Cameroon)], E-mail: hbfotsin@yahoo.fr

    2008-04-15

    This paper deals with chaos control and synchronization in forced Bonhoeffer-van der Pol (FBVP) oscillators. The state equations of the model are first established and the stability is analysed. A feedback control strategy for stabilizing the chaotic dynamics on a periodic orbit of the phase space is investigated. Adaptive synchronization of two FBVP oscillators, based on parameter estimation and a nonlinear observer approach, is also investigated. It appears that a particular unknown parameter of the model can be estimated, which gives the possibility of recovering information through chaotic masking. An application in secure communications is presented.

  18. Feedback control and adaptive synchronization of chaotic forced Bonhoeffer-van der Pol oscillators

    International Nuclear Information System (INIS)

    Kontchou, E W Chimi; Fotsin, H B; Woafo, P

    2008-01-01

    This paper deals with chaos control and synchronization in forced Bonhoeffer-van der Pol (FBVP) oscillators. The state equations of the model are first established and the stability is analysed. A feedback control strategy for stabilizing the chaotic dynamics on a periodic orbit of the phase space is investigated. Adaptive synchronization of two FBVP oscillators, based on parameter estimation and a nonlinear observer approach, is also investigated. It appears that a particular unknown parameter of the model can be estimated, which gives the possibility of recovering information through chaotic masking. An application in secure communications is presented

  19. Comparative Effects of Different Balance-Training–Progression Styles on Postural Control and Ankle Force Production: A Randomized Controlled Trial

    Science.gov (United States)

    Cuğ, Mutlu; Duncan, Ashley; Wikstrom, Erik

    2016-01-01

    Context:  Despite the effectiveness of balance training, the exact parameters needed to maximize the benefits of such programs remain unknown. One such factor is how individuals should progress to higher levels of task difficulty within a balance-training program. Yet no investigators have directly compared different balance-training–progression styles. Objective:  To compare an error-based progression (ie, advance when proficient at a task) with a repetition-based progression (ie, advance after a set amount of repetitions) style during a balance-training program in healthy individuals. Design:  Randomized controlled trial. Setting:  Research laboratory. Patients or Other Participants:  A total of 28 (16 women, 12 men) physically healthy young adults (age = 21.57 ± 3.95 years, height = 171.60 ± 11.03 cm, weight = 72.96 ± 16.18 kg, body mass index = 24.53 ± 3.7). Intervention(s):  All participants completed 12 supervised balance-training sessions over 4 weeks. Each session consisted of a combination of dynamic unstable-surface tasks that incorporated a BOSU ball and lasted about 30 minutes. Main Outcome Measure(s):  Static balance from an instrumented force plate, dynamic balance as measured via the Star Excursion Balance Test, and ankle force production in all 4 cardinal planes of motion as measured with a handheld dynamometer before and after the intervention. Results:  Selected static postural-control outcomes, dynamic postural control, and ankle force production in all planes of motion improved (P .05) for any of the outcome measures. Conclusions:  A 4-week balance-training program consisting of dynamic unstable-surface exercises on a BOSU ball improved dynamic postural control and ankle force production in healthy young adults. These results suggest that an error-based balance-training program is comparable with but not superior to a repetition-based balance-training program in improving postural control and ankle force production in

  20. Forced-Air Warming Provides Better Control of Body Temperature in Porcine Surgical Patients

    Directory of Open Access Journals (Sweden)

    Brian T. Dent

    2016-09-01

    Full Text Available Background: Maintaining normothermia during porcine surgery is critical in ensuring subject welfare and recovery, reducing the risk of immune system compromise and surgical-site infection that can result from hypothermia. In humans, various methods of patient heating have been demonstrated to be useful, but less evaluation has been performed in techniques to prevent hypothermia perioperatively in pigs. Methods: We compared body temperature regulation during surgery before and after modification of the ambient temperature of the operating laboratories. Three different methods of heating were then compared; a standard circulating water mattress, a resistive fabric blanket, and a forced hot air system. The primary measure was percentage of temperature readings outside a specification range of 36.7–40.0 °C. Results: Tighter control of the ambient temperature while using a circulating water mattress reduced the occurrence of out-of-specification body temperature readings from 20.8% to 5.0%, with most of these the result of hypothermia. Use of a resistive fabric blanket further reduced out-of-specification readings to 1.5%, with a slight increase in the occurrence of hyperthermia. Use of a forced air system reduced out-of-specification readings to less 0.1%. Conclusions: Maintenance of normothermia perioperatively in pig can be improved by tightly controlling ambient temperatures. Use of a resistive blanket or a forced air system can lead to better control than a circulating water mattress, with the forced air system providing a faster response to temperature variations and less chance of hyperthermia.

  1. Real-time changes in corticospinal excitability related to motor imagery of a force control task.

    Science.gov (United States)

    Tatemoto, Tsuyoshi; Tsuchiya, Junko; Numata, Atsuki; Osawa, Ryuji; Yamaguchi, Tomofumi; Tanabe, Shigeo; Kondo, Kunitsugu; Otaka, Yohei; Sugawara, Kenichi

    2017-09-29

    To investigate real-time excitability changes in corticospinal pathways related to motor imagery in a changing force control task, using transcranial magnetic stimulation (TMS). Ten healthy volunteers learnt to control the contractile force of isometric right wrist dorsiflexion in order to track an on-screen sine wave form. Participants performed the trained task 40 times with actual muscle contraction in order to construct the motor image. They were then instructed to execute the task without actual muscle contraction, but by imagining contraction of the right wrist in dorsiflexion. Motor evoked potentials (MEPs), induced by TMS in the right extensor carpi radialis muscle (ECR) and flexor carpi radialis muscle (FCR), were measured during motor imagery. MEPs were induced at five time points: prior to imagery, during the gradual generation of the imaged wrist dorsiflexion (Increasing phase), the peak value of the sine wave, during the gradual reduction (Decreasing phase), and after completion of the task. The MEP ratio, as the ratio of imaged MEPs to resting-state, was compared between pre- and post-training at each time point. In the ECR muscle, the MEP ratio significantly increased during the Increasing phase and at the peak force of dorsiflexion imagery after training. Moreover, the MEP ratio was significantly greater in the Increasing phase than in the Decreasing phase. In the FCR, there were no significant consistent changes. Corticospinal excitability during motor imagery in an isometric contraction task was modulated in relation to the phase of force control after image construction. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Redundancy scheme for multi-layered accelerator control system

    International Nuclear Information System (INIS)

    Chauhan, Amit; Fatnani, Pravin

    2009-01-01

    The control system for SRS Indus-2 has three-layered architecture. There are VMEbus based stations at the lower two layers that are controlled by their respective CPU board. The 'Profibus' fieldbus standard is used for communication between these VME stations distributed in the field. There is a Profibus controller board at each station to implement the communication protocol. The mode of communication is master-slave (command-response) type. This paper proposes a scheme to implement redundancy at the lower two layers namely Layer-2 (Supervisory Layer / Profibus-master) and Layer-3 (Equipment Unit Interface Layer / Profibus-slave). The redundancy is for both the CPU and the communication board. The scheme uses two CPU boards and two Profi controller boards at each L-3 station. This helps in decreasing any downtime resulting either from CPU faults or communication board faults that are placed in the field area. Redundancy of Profi boards provides two active communication channels between the stations that can be used in different ways thereby increasing the availability on a communication link. Redundancy of CPU boards provides certain level of auto fault-recovery as one CPU remains active and the other CPU remains in standby mode, which takes over the control of VMEbus in case of any fault in the main CPU. (author)

  3. Force to Rebalance Control of HRG and Suppression of Its Errors on the Basis of FPGA

    Directory of Open Access Journals (Sweden)

    Qingan Jiang

    2011-12-01

    Full Text Available A novel design of force to rebalance control for a hemispherical resonator gyro (HRG based on FPGA is demonstrated in this paper. The proposed design takes advantage of the automatic gain control loop and phase lock loop configuration in the drive mode while making full use of the quadrature control loop and rebalance control loop in controlling the oscillating dynamics in the sense mode. First, the math model of HRG with inhomogeneous damping and frequency split is theoretically analyzed. In addition, the major drift mechanisms in the HRG are described and the methods that can suppress the gyro drift are mentioned. Based on the math model and drift mechanisms suppression method, four control loops are employed to realize the manipulation of the HRG by using a FPGA circuit. The reference-phase loop and amplitude control loop are used to maintain the vibration of primary mode at its natural frequency with constant amplitude. The frequency split is readily eliminated by the quadrature loop with a DC voltage feedback from the quadrature component of the node. The secondary mode response to the angle rate input is nullified by the rebalance control loop. In order to validate the effect of the digital control of HRG, experiments are carried out with a turntable. The experimental results show that the design is suitable for the control of HRG which has good linearity scale factor and bias stability.

  4. Force to rebalance control of HRG and suppression of its errors on the basis of FPGA.

    Science.gov (United States)

    Wang, Xu; Wu, Wenqi; Luo, Bing; Fang, Zhen; Li, Yun; Jiang, Qingan

    2011-01-01

    A novel design of force to rebalance control for a hemispherical resonator gyro (HRG) based on FPGA is demonstrated in this paper. The proposed design takes advantage of the automatic gain control loop and phase lock loop configuration in the drive mode while making full use of the quadrature control loop and rebalance control loop in controlling the oscillating dynamics in the sense mode. First, the math model of HRG with inhomogeneous damping and frequency split is theoretically analyzed. In addition, the major drift mechanisms in the HRG are described and the methods that can suppress the gyro drift are mentioned. Based on the math model and drift mechanisms suppression method, four control loops are employed to realize the manipulation of the HRG by using a FPGA circuit. The reference-phase loop and amplitude control loop are used to maintain the vibration of primary mode at its natural frequency with constant amplitude. The frequency split is readily eliminated by the quadrature loop with a DC voltage feedback from the quadrature component of the node. The secondary mode response to the angle rate input is nullified by the rebalance control loop. In order to validate the effect of the digital control of HRG, experiments are carried out with a turntable. The experimental results show that the design is suitable for the control of HRG which has good linearity scale factor and bias stability.

  5. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    International Nuclear Information System (INIS)

    Yao, Jianyong; Jiao, Zongxia; Yao, Bin

    2014-01-01

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  6. Nonlinear adaptive robust back stepping force control of hydraulic load simulator: Theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Jianyong [Nanjing University of Science and Technology, Nanjing (China); Jiao, Zongxia [Beihang University, Beijing (China); Yao, Bin [Purdue University, West Lafayette (United States)

    2014-04-15

    High performance robust force control of hydraulic load simulator with constant but unknown hydraulic parameters is considered. In contrast to the linear control based on hydraulic linearization equations, hydraulic inherent nonlinear properties and uncertainties make the conventional feedback proportional-integral-derivative (PID) control not yield to high performance requirements. Furthermore, the hydraulic system may be subjected to non-smooth and discontinuous nonlinearities due to the directional change of valve opening. In this paper, based on a nonlinear system model of hydraulic load simulator, a discontinuous projection-based nonlinear adaptive robust back stepping controller is developed with servo valve dynamics. The proposed controller constructs a novel stable adaptive controller and adaptation laws with additional pressure dynamic related unknown parameters, which can compensate for the system nonlinearities and uncertain parameters, meanwhile a well-designed robust controller is also synthesized to dominate the model uncertainties coming from both parametric uncertainties and uncertain nonlinearities including unmodeled and ignored system dynamics. The controller theoretically guarantee a prescribed transient performance and final tracking accuracy in presence of both parametric uncertainties and uncertain nonlinearities; while achieving asymptotic output tracking in the absence of unstructured uncertainties. The implementation issues are also discussed for controller simplification. Some comparative results are obtained to verify the high-performance nature of the proposed controller.

  7. Controlled assembly of multi-segment nanowires by histidine-tagged peptides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aijun A; Lee, Joun; Jenikova, Gabriela; Mulchandani, Ashok; Myung, Nosang V; Chen, Wilfred [Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521 (United States)

    2006-07-28

    A facile technique was demonstrated for the controlled assembly and alignment of multi-segment nanowires using bioengineered polypeptides. An elastin-like-polypeptide (ELP)-based biopolymer consisting of a hexahistine cluster at each end (His{sub 6}-ELP-His{sub 6}) was generated and purified by taking advantage of the reversible phase transition property of ELP. The affinity between the His{sub 6} domain of biopolymers and the nickel segment of multi-segment nickel/gold/nickel nanowires was exploited for the directed assembly of nanowires onto peptide-functionalized electrode surfaces. The presence of the ferromagnetic nickel segments on the nanowires allowed the control of directionality by an external magnetic field. Using this method, the directed assembly and positioning of multi-segment nanowires across two microfabricated nickel electrodes in a controlled manner was accomplished with the expected ohmic contact.

  8. Generation and control of multi-scroll chaotic attractors in fractional order systems

    International Nuclear Information System (INIS)

    Ahmad, Wajdi M.

    2005-01-01

    The objective of this paper is twofold: on one hand we demonstrate the generation of multi-scroll attractors in fractional order chaotic systems. Then, we design state feedback controllers to eliminate chaos from the system trajectories. It is demonstrated that modifying the underlying nonlinearity of the fractional chaotic system results in the birth of multiple chaotic attractors, thus forming the so called multi-scroll attractors. The presence of chaotic behavior is evidenced by a positive largest Lyapunov exponent computed for the output time series. We investigate generation and control of multi-scroll attractors in two different models, both of which are fractional order and chaotic: an electronic oscillator, and a mechanical 'jerk' model. The current findings extend previously reported results on generation of n-scroll attractors from the domain of integer order to the domain of fractional order chaotic systems, and addresses the issue of controlling such chaotic behaviors. Our investigations are validated through numerical simulations

  9. Modelling and Multi-Variable Control of Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Slot; Holm, J. R.

    2003-01-01

    In this paper a dynamic model of a 1:1 refrigeration system is presented. The main modelling effort has been concentrated on a lumped parameter model of a shell and tube condenser. The model has shown good resemblance with experimental data from a test rig, regarding as well the static as the dyn......In this paper a dynamic model of a 1:1 refrigeration system is presented. The main modelling effort has been concentrated on a lumped parameter model of a shell and tube condenser. The model has shown good resemblance with experimental data from a test rig, regarding as well the static...... as the dynamic behavior. Based on this model the effects of the cross couplings has been examined. The influence of the cross couplings on the achievable control performance has been investigated. A MIMO controller is designed and the performance is compared with the control performance achieved by using...

  10. Visual feedback alters force control and functional activity in the visuomotor network after stroke

    Directory of Open Access Journals (Sweden)

    Derek B. Archer

    2018-01-01

    Full Text Available Modulating visual feedback may be a viable option to improve motor function after stroke, but the neurophysiological basis for this improvement is not clear. Visual gain can be manipulated by increasing or decreasing the spatial amplitude of an error signal. Here, we combined a unilateral visually guided grip force task with functional MRI to understand how changes in the gain of visual feedback alter brain activity in the chronic phase after stroke. Analyses focused on brain activation when force was produced by the most impaired hand of the stroke group as compared to the non-dominant hand of the control group. Our experiment produced three novel results. First, gain-related improvements in force control were associated with an increase in activity in many regions within the visuomotor network in both the stroke and control groups. These regions include the extrastriate visual cortex, inferior parietal lobule, ventral premotor cortex, cerebellum, and supplementary motor area. Second, the stroke group showed gain-related increases in activity in additional regions of lobules VI and VIIb of the ipsilateral cerebellum. Third, relative to the control group, the stroke group showed increased activity in the ipsilateral primary motor cortex, and activity in this region did not vary as a function of visual feedback gain. The visuomotor network, cerebellum, and ipsilateral primary motor cortex have each been targeted in rehabilitation interventions after stroke. Our observations provide new insight into the role these regions play in processing visual gain during a precisely controlled visuomotor task in the chronic phase after stroke.

  11. Modelling and control system of multi motor conveyor

    Science.gov (United States)

    Kovalchuk, M. S.; Baburin, S. V.

    2018-03-01

    The paper deals with the actual problem of developing the mathematical model of electromechanical system: conveyor – multimotor electric drive with a frequency converter, with the implementation in Simulink/MatLab, which allows one to perform studies of conveyor operation modes, taking into account the specifics of the mechanism with different electric drives control algorithms. The authors designed the mathematical models of the conveyor and its control system that provides increased uniformity of load distribution between drive motors and restriction of dynamic loads on the belt (over-regulation until 15%).

  12. Force Modeling, Identification, and Feedback Control of Robot-Assisted Needle Insertion: A Survey of the Literature

    Directory of Open Access Journals (Sweden)

    Chongjun Yang

    2018-02-01

    Full Text Available Robot-assisted surgery is of growing interest in the surgical and engineering communities. The use of robots allows surgery to be performed with precision using smaller instruments and incisions, resulting in shorter healing times. However, using current technology, an operator cannot directly feel the operation because the surgeon-instrument and instrument-tissue interaction force feedbacks are lost during needle insertion. Advancements in force feedback and control not only help reduce tissue deformation and needle deflection but also provide the surgeon with better control over the surgical instruments. The goal of this review is to summarize the key components surrounding the force feedback and control during robot-assisted needle insertion. The literature search was conducted during the middle months of 2017 using mainstream academic search engines with a combination of keywords relevant to the field. In total, 166 articles with valuable contents were analyzed and grouped into five related topics. This survey systemically summarizes the state-of-the-art force control technologies for robot-assisted needle insertion, such as force modeling, measurement, the factors that influence the interaction force, parameter identification, and force control algorithms. All studies show force control is still at its initial stage. The influence factors, needle deflection or planning remain open for investigation in future.

  13. Force Modeling, Identification, and Feedback Control of Robot-Assisted Needle Insertion: A Survey of the Literature.

    Science.gov (United States)

    Yang, Chongjun; Xie, Yu; Liu, Shuang; Sun, Dong

    2018-02-12

    Robot-assisted surgery is of growing interest in the surgical and engineering communities. The use of robots allows surgery to be performed with precision using smaller instruments and incisions, resulting in shorter healing times. However, using current technology, an operator cannot directly feel the operation because the surgeon-instrument and instrument-tissue interaction force feedbacks are lost during needle insertion. Advancements in force feedback and control not only help reduce tissue deformation and needle deflection but also provide the surgeon with better control over the surgical instruments. The goal of this review is to summarize the key components surrounding the force feedback and control during robot-assisted needle insertion. The literature search was conducted during the middle months of 2017 using mainstream academic search engines with a combination of keywords relevant to the field. In total, 166 articles with valuable contents were analyzed and grouped into five related topics. This survey systemically summarizes the state-of-the-art force control technologies for robot-assisted needle insertion, such as force modeling, measurement, the factors that influence the interaction force, parameter identification, and force control algorithms. All studies show force control is still at its initial stage. The influence factors, needle deflection or planning remain open for investigation in future.

  14. Low-noise humidity controller for imaging water mediated processes in atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gaponenko, I., E-mail: iaroslav.gaponenko@unige.ch; Gamperle, L.; Herberg, K.; Muller, S. C.; Paruch, P. [DQMP, University of Geneva, 24 Quai E. Ansermet, 1211 Geneva 4 (Switzerland)

    2016-06-15

    We demonstrate the construction of a novel low-noise continuous flow humidity controller and its integration with a commercial variable-temperature atomic force microscope fluid cell, allowing precise control of humidity and temperature at the sample during nanoscale measurements. Based on wet and dry gas mixing, the design allows a high mechanical stability to be achieved by means of an ultrasonic atomiser for the generation of water-saturated gas, improving upon previous bubbler-based architectures. Water content in the flow is measured both at the inflow and outflow of the fluid cell, enabling the monitoring of water condensation and icing, and allowing controlled variation of the sample temperature independently of the humidity. To benchmark the performance of the controller, the results of detailed noise studies and time-based imaging of the formation of ice layers on highly oriented pyrolytic graphite are shown.

  15. Low-noise humidity controller for imaging water mediated processes in atomic force microscopy

    Science.gov (United States)

    Gaponenko, I.; Gamperle, L.; Herberg, K.; Muller, S. C.; Paruch, P.

    2016-06-01

    We demonstrate the construction of a novel low-noise continuous flow humidity controller and its integration with a commercial variable-temperature atomic force microscope fluid cell, allowing precise control of humidity and temperature at the sample during nanoscale measurements. Based on wet and dry gas mixing, the design allows a high mechanical stability to be achieved by means of an ultrasonic atomiser for the generation of water-saturated gas, improving upon previous bubbler-based architectures. Water content in the flow is measured both at the inflow and outflow of the fluid cell, enabling the monitoring of water condensation and icing, and allowing controlled variation of the sample temperature independently of the humidity. To benchmark the performance of the controller, the results of detailed noise studies and time-based imaging of the formation of ice layers on highly oriented pyrolytic graphite are shown.

  16. Low-noise humidity controller for imaging water mediated processes in atomic force microscopy

    International Nuclear Information System (INIS)

    Gaponenko, I.; Gamperle, L.; Herberg, K.; Muller, S. C.; Paruch, P.

    2016-01-01

    We demonstrate the construction of a novel low-noise continuous flow humidity controller and its integration with a commercial variable-temperature atomic force microscope fluid cell, allowing precise control of humidity and temperature at the sample during nanoscale measurements. Based on wet and dry gas mixing, the design allows a high mechanical stability to be achieved by means of an ultrasonic atomiser for the generation of water-saturated gas, improving upon previous bubbler-based architectures. Water content in the flow is measured both at the inflow and outflow of the fluid cell, enabling the monitoring of water condensation and icing, and allowing controlled variation of the sample temperature independently of the humidity. To benchmark the performance of the controller, the results of detailed noise studies and time-based imaging of the formation of ice layers on highly oriented pyrolytic graphite are shown.

  17. Vortexlet models of flapping flexible wings show tuning for force production and control

    International Nuclear Information System (INIS)

    Mountcastle, A M; Daniel, T L

    2010-01-01

    Insect wings are compliant structures that experience deformations during flight. Such deformations have recently been shown to substantially affect induced flows, with appreciable consequences to flight forces. However, there are open questions related to the aerodynamic mechanisms underlying the performance benefits of wing deformation, as well as the extent to which such deformations are determined by the boundary conditions governing wing actuation together with mechanical properties of the wing itself. Here we explore aerodynamic performance parameters of compliant wings under periodic oscillations, subject to changes in phase between wing elevation and pitch, and magnitude and spatial pattern of wing flexural stiffness. We use a combination of computational structural mechanics models and a 2D computational fluid dynamics approach to ask how aerodynamic force production and control potential are affected by pitch/elevation phase and variations in wing flexural stiffness. Our results show that lift and thrust forces are highly sensitive to flexural stiffness distributions, with performance optima that lie in different phase regions. These results suggest a control strategy for both flying animals and engineering applications of micro-air vehicles.

  18. Evaluating Statistical Process Control (SPC) techniques and computing the uncertainty of force calibrations

    Science.gov (United States)

    Navard, Sharon E.

    1989-01-01

    In recent years there has been a push within NASA to use statistical techniques to improve the quality of production. Two areas where statistics are used are in establishing product and process quality control of flight hardware and in evaluating the uncertainty of calibration of instruments. The Flight Systems Quality Engineering branch is responsible for developing and assuring the quality of all flight hardware; the statistical process control methods employed are reviewed and evaluated. The Measurement Standards and Calibration Laboratory performs the calibration of all instruments used on-site at JSC as well as those used by all off-site contractors. These calibrations must be performed in such a way as to be traceable to national standards maintained by the National Institute of Standards and Technology, and they must meet a four-to-one ratio of the instrument specifications to calibrating standard uncertainty. In some instances this ratio is not met, and in these cases it is desirable to compute the exact uncertainty of the calibration and determine ways of reducing it. A particular example where this problem is encountered is with a machine which does automatic calibrations of force. The process of force calibration using the United Force Machine is described in detail. The sources of error are identified and quantified when possible. Suggestions for improvement are made.

  19. Balancing the intermolecular forces in peptide amphiphiles for controlling self-assembly transitions.

    Science.gov (United States)

    Buettner, C J; Wallace, A J; Ok, S; Manos, A A; Nicholl, M J; Ghosh, A; Tweedle, M F; Goldberger, J E

    2017-06-21

    While the influence of alkyl chain length and headgroup size on self-assembly behaviour has been well-established for simple surfactants, the rational control over the pH- and concentration-dependent self-assembly behaviour in stimuli responsive peptides remains an elusive goal. Here, we show that different amphiphilic peptides can have similar self-assembly phase diagrams, providing the relative strengths of the attractive and repulsive forces are balanced. Using palmitoyl-YYAAEEEEK(DO3A:Gd)-NH 2 and palmitoyl-YAAEEEEK(DO3A:Gd)-NH 2 as controls, we show that reducing hydrophobic attractive forces through fewer methylene groups in the alkyl chain will lead to a similar self-assembly phase diagram as increasing the electrostatic repulsive forces via the addition of a glutamic acid residue. These changes allow creation of self-assembled MRI vehicles with slightly different micelle and nanofiber diameters but with minimal changes in the spin-lattice T 1 relaxivity. These findings reveal a powerful strategy to design self-assembled vehicles with different sizes but with similar self-assembly profiles.

  20. Inventory control in multi-item production systems

    NARCIS (Netherlands)

    Bruin, J.

    2010-01-01

    This thesis focusses on the analysis and construction of control policies in multiitem production systems. In such systems, multiple items can be made to stock, but they have to share the finite capacity of a single machine. This machine can only produce one unit at a time and if it is set-up for