asymptotics for open-loop window flow control
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Arthur W. Berger
1994-01-01
Full Text Available An open-loop window flow-control scheme regulates the flow into a system by allowing at most a specified window size W of flow in any interval of length L. The sliding window considers all subintervals of length L, while the jumping window considers consecutive disjoint intervals of length L. To better understand how these window control schemes perform for stationary sources, we describe for a large class of stochastic input processes the asymptotic behavior of the maximum flow in such window intervals over a time interval [0,T] as T and Lget large, with T substantially bigger than L. We use strong approximations to show that when T≫L≫logT an invariance principle holds, so that the asymptotic behavior depends on the stochastic input process only via its rate and asymptotic variability parameters. In considerable generality, the sliding and jumping windows are asymptotically equivalent. We also develop an approximate relation between the two maximum window sizes. We apply the asymptotic results to develop approximations for the means and standard deviations of the two maximum window contents. We apply computer simulation to evaluate and refine these approximations.
Integrated open loop control and design of a food storage room
Mourik, van S.; Zwart, H.; Keesman, K.J.
2009-01-01
Usually, control design in a food storage room takes place after the plant has been designed. However, the performance of the plant connected to the controller might be improved by simultaneous design of the plant and the controller. In the case of open loop control, expressions that describe the dy
Open-loop versus closed-loop control of MEMS devices: choices and issues
Borovic, B.; Liu, A. Q.; Popa, D.; Cai, H.; Lewis, F. L.
2005-10-01
From a controls point of view, micro electromechanical systems (MEMS) can be driven in an open-loop and closed-loop fashion. Commonly, these devices are driven open-loop by applying simple input signals. If these input signals become more complex by being derived from the system dynamics, we call such control techniques pre-shaped open-loop driving. The ultimate step for improving precision and speed of response is the introduction of feedback, e.g. closed-loop control. Unlike macro mechanical systems, where the implementation of the feedback is relatively simple, in the MEMS case the feedback design is quite problematic, due to the limited availability of sensor data, the presence of sensor dynamics and noise, and the typically fast actuator dynamics. Furthermore, a performance comparison between open-loop and closed-loop control strategies has not been properly explored for MEMS devices. The purpose of this paper is to present experimental results obtained using both open- and closed-loop strategies and to address the comparative issues of driving and control for MEMS devices. An optical MEMS switching device is used for this study. Based on these experimental results, as well as computer simulations, we point out advantages and disadvantages of the different control strategies, address the problems that distinguish MEMS driving systems from their macro counterparts, and discuss criteria to choose a suitable control driving strategy.
Control software analysis, Part I Open-loop properties
Feron, Eric
2008-01-01
As the digital world enters further into everyday life, questions are raised about the increasing challenges brought by the interaction of real-time software with physical devices. Many accidents and incidents encountered in areas as diverse as medical systems, transportation systems or weapon systems are ultimately attributed to "software failures". Since real-time software that interacts with physical systems might as well be called control software, the long litany of accidents due to real-time software failures might be taken as an equally long list of opportunities for control systems engineering. In this paper, we are interested only in run-time errors in those pieces of software that are a direct implementation of control system specifications: For well-defined and well-understood control architectures such as those present in standard textbooks on digital control systems, the current state of theoretical computer science is well-equipped enough to address and analyze control algorithms. It appears tha...
Wang, Xu; Saberi, Ali; Grip, H°avard Fjær; Stoorvogel, Antonie Arij
2013-01-01
In this paper, we study the disturbance response of open-loop neutrally stable linear systems with saturating linear feedback controller. It is shown that the closed-loop states remain bounded if the disturbances con- sists of those signals that do not have large sustained frequency components
Open-loop quantum control as a resource for secure communications
Pastorello, Davide
2016-05-01
Properties of unitary time evolution of quantum systems can be applied to define quantum cryptographic protocols. Dynamics of a qubit can be exploited as a data encryption/decryption procedure by means of timed measurements, implementation of an open-loop control scheme over a qubit increases robustness of a protocol employing this principle.
Open-loop quantum control as a resource for secure communications
Pastorello, Davide
2015-01-01
Properties of unitary time evolution of quantum systems can be applied to define quantum cryptographic protocols. Dynamics of a qubit can be exploited as a data encryption/decryption procedure by means of timed measurements, implementation of an open-loop control scheme over a qubit increases robustness of a protocol employing this principle.
Increasing Mission Reliability Using Open-Loop Control
1993-08-01
Jersey, 1986. 2. J. J. DiStefano, A. R. Stubberud, and I. J. Williams , Feedback and Control Systems - Schaum’s Outline, McGraw-Hill, New York, 1967. 3. Z...ATTN: SMCRI-ENM THE PENTAGON ROCK ISLAND, IL 61299-5000 WASHINGTON. D.C. 20310-0103 MIAC/ CINDAS ADMINISTRATOR PURDUE UNIVERSITY DEFENSE TECHNICAL INFO
OPEN-LOOP CONTROL OF A BIPOLAR STEPPER MOTORS USING THE SPECIALIZED INTEGRATED CIRCUITS
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Gheorghe BALUTA
2004-12-01
Full Text Available This paper describes the open-loop control of a stepper motors. Bipolar stepper motors can be driven with an L297, an L298N bridge driver and very few external components. With an L298N this configuration drives motors with winding currents up to 2.5A. If very high powers are required an equivalent circuit made with discrete transistors replaces the bridge driver. Together these two chips form a complete microprocessor-to-stepper motor interface. The command signals for the controller L297 are generated through an IBM-PC486 interface. It was developed an open-loop command program written in BorlandC programming language.
Control-Relevant Identification Test Design for Open-Loop Experiment
Institute of Scientific and Technical Information of China (English)
张立群; 邵惠鹤
2004-01-01
An optimal experiment design (DED) with respect to the use of designing model-base controller was studied. The mean squared error at the setpoint is chosen as the performance criterion. Simple design formulas are derived based on the asymptotic theory. The signal is used for the open loop experiment. The design constraint is the power of the process signal or the process input signal. The results give guideline for identification application.
Multiple model-informed open-loop control of uncertain intracellular signaling dynamics.
Directory of Open Access Journals (Sweden)
Jeffrey P Perley
2014-04-01
Full Text Available Computational approaches to tune the activation of intracellular signal transduction pathways both predictably and selectively will enable researchers to explore and interrogate cell biology with unprecedented precision. Techniques to control complex nonlinear systems typically involve the application of control theory to a descriptive mathematical model. For cellular processes, however, measurement assays tend to be too time consuming for real-time feedback control and models offer rough approximations of the biological reality, thus limiting their utility when considered in isolation. We overcome these problems by combining nonlinear model predictive control with a novel adaptive weighting algorithm that blends predictions from multiple models to derive a compromise open-loop control sequence. The proposed strategy uses weight maps to inform the controller of the tendency for models to differ in their ability to accurately reproduce the system dynamics under different experimental perturbations (i.e. control inputs. These maps, which characterize the changing model likelihoods over the admissible control input space, are constructed using preexisting experimental data and used to produce a model-based open-loop control framework. In effect, the proposed method designs a sequence of control inputs that force the signaling dynamics along a predefined temporal response without measurement feedback while mitigating the effects of model uncertainty. We demonstrate this technique on the well-known Erk/MAPK signaling pathway in T cells. In silico assessment demonstrates that this approach successfully reduces target tracking error by 52% or better when compared with single model-based controllers and non-adaptive multiple model-based controllers. In vitro implementation of the proposed approach in Jurkat cells confirms a 63% reduction in tracking error when compared with the best of the single-model controllers. This study provides an experimentally
Multiple model-informed open-loop control of uncertain intracellular signaling dynamics.
Perley, Jeffrey P; Mikolajczak, Judith; Harrison, Marietta L; Buzzard, Gregery T; Rundell, Ann E
2014-04-01
Computational approaches to tune the activation of intracellular signal transduction pathways both predictably and selectively will enable researchers to explore and interrogate cell biology with unprecedented precision. Techniques to control complex nonlinear systems typically involve the application of control theory to a descriptive mathematical model. For cellular processes, however, measurement assays tend to be too time consuming for real-time feedback control and models offer rough approximations of the biological reality, thus limiting their utility when considered in isolation. We overcome these problems by combining nonlinear model predictive control with a novel adaptive weighting algorithm that blends predictions from multiple models to derive a compromise open-loop control sequence. The proposed strategy uses weight maps to inform the controller of the tendency for models to differ in their ability to accurately reproduce the system dynamics under different experimental perturbations (i.e. control inputs). These maps, which characterize the changing model likelihoods over the admissible control input space, are constructed using preexisting experimental data and used to produce a model-based open-loop control framework. In effect, the proposed method designs a sequence of control inputs that force the signaling dynamics along a predefined temporal response without measurement feedback while mitigating the effects of model uncertainty. We demonstrate this technique on the well-known Erk/MAPK signaling pathway in T cells. In silico assessment demonstrates that this approach successfully reduces target tracking error by 52% or better when compared with single model-based controllers and non-adaptive multiple model-based controllers. In vitro implementation of the proposed approach in Jurkat cells confirms a 63% reduction in tracking error when compared with the best of the single-model controllers. This study provides an experimentally
Coherent open-loop optimal control of light-harvesting dynamics
Caruso, Filippo; Calarco, Tommaso; Huelga, Susana F; Plenio, Martin B
2011-01-01
We apply theoretically open-loop quantum optimal control techniques to provide methods for the verification of various quantum coherent transport mechanisms in natural and artificial light-harvesting complexes under realistic experimental constraints. We demonstrate that optimally shaped laser pulses allow to faithfully prepare the photosystem in specified initial states (such as localized excitation or coherent superposition, i.e. propagating and non-propagating states) and to probe efficiently the dynamics. These results provide a path towards the discrimination of the different transport pathways and to the characterization of environmental properties, enhancing our understanding of the role that coherent processes may play in biological complexes.
A self-tuning digital-driver for open-loop control of stepping-motors
Energy Technology Data Exchange (ETDEWEB)
Okada, T.; Hori, N. [Tsukuba Univ., Tsukuba, Ibarki (Japan). Intelligent Interaction Technologies, Graduate School of Systems and Information Engineering
2010-08-13
Stepping motors are commonly used as actuators in industrial control applications because of the their high torque-to-weight ratio, precise and quick positioning, and self-hold capability. They can also be controlled in an open-loop fashion using a proper driver. This paper described the design of an experimental digital driver, which contained both fixed and adjustable gains. It also discussed a current regulation problem for a stepping-motor which underwent rapid and large changes in its gains. An open-loop nature of a stepping motor could be preserved using only signals that are readily available in the driver and do not require neither the angular position of the shaft nor its rate. Specifically, the paper discussed the stepping motor and driver, parameter variations, dead-zone compensation, nonlinear digital filter, and anti-aliasing filter. The self-tuning algorithm was also presented with particular reference to background controller design and self tuning pre-compensator. The experiments and parameters used in the experiments were also described. It was concluded that stable and safe operations can be achieved using a combination of fixed controller blocks and precompensator blocks with self-tuning parameters, which change as the speed of rotation varies. For this method to work, it is important to include a dead-zone compensator and a nonlinear digital filter and an anti-aliasing filter. 7 refs., 1 tab., 15 figs.
Directory of Open Access Journals (Sweden)
Russel J Stonier
2003-08-01
Full Text Available In this paper we examine the application of evolutionary algorithms to find open-loop control solutions of the optimal control problem arising from the semidiscretisation of a linear parabolic tracking problem with boundary control. The solution is compared with the solutions obtained by methods based upon the variational equations of the Minimum Principle and the finite element method.
On Sequence Learning Models: Open-loop Control Not Strictly Guided by Hick's Law.
Pavão, Rodrigo; Savietto, Joice P; Sato, João R; Xavier, Gilberto F; Helene, André F
2016-03-15
According to the Hick's law, reaction times increase linearly with the uncertainty of target stimuli. We tested the generality of this law by measuring reaction times in a human sequence learning protocol involving serial target locations which differed in transition probability and global entropy. Our results showed that sigmoid functions better describe the relationship between reaction times and uncertainty when compared to linear functions. Sequence predictability was estimated by distinct statistical predictors: conditional probability, conditional entropy, joint probability and joint entropy measures. Conditional predictors relate to closed-loop control models describing that performance is guided by on-line access to past sequence structure to predict next location. Differently, joint predictors relate to open-loop control models assuming global access of sequence structure, requiring no constant monitoring. We tested which of these predictors better describe performance on the sequence learning protocol. Results suggest that joint predictors are more accurate than conditional predictors to track performance. In conclusion, sequence learning is better described as an open-loop process which is not precisely predicted by Hick's law.
Open-Loop Control in Quantum Optics: Two-Level Atom in Modulated Optical Field
Saifullah, Sergei
2008-01-01
The methods of mathematical control theory are widely used in the modern physics, but still they are less popular in quantum science. We will discuss the aspects of control theory, which are the most useful in applications to the real problems of quantum optics. We apply this technique to control the behavior of the two-level quantum particles (atoms) in the modulated external optical field in the frame of the so called "semi classical model", where quantum two-level atomic system (all other levels are neglected) interacts with classical electromagnetic field. In this paper we propose a simple model of feedforward (open-loop) control for the quantum particle system, which is a basement for further investigation of two-level quantum particle in the external one-dimensional optical field.
Open-Loop HIRF Experiments Performed on a Fault Tolerant Flight Control Computer
Koppen, Daniel M.
1997-01-01
During the third quarter of 1996, the Closed-Loop Systems Laboratory was established at the NASA Langley Research Center (LaRC) to study the effects of High Intensity Radiated Fields on complex avionic systems and control system components. This new facility provided a link and expanded upon the existing capabilities of the High Intensity Radiated Fields Laboratory at LaRC that were constructed and certified during 1995-96. The scope of the Closed-Loop Systems Laboratory is to place highly integrated avionics instrumentation into a high intensity radiated field environment, interface the avionics to a real-time flight simulation that incorporates aircraft dynamics, engines, sensors, actuators and atmospheric turbulence, and collect, analyze, and model aircraft performance. This paper describes the layout and functionality of the Closed-Loop Systems Laboratory, and the open-loop calibration experiments that led up to the commencement of closed-loop real-time flight experiments.
Experimental evaluation of open-loop UpLink Power Control using ACTS
Dissanayake, Asoka
1995-01-01
The present investigation deals with the implementation of open-loop up-link power control using a beacon signal in the down-link frequency band as the control parameter. A power control system was developed and tested using the ACTS satellite. ACTS carries beacon signals in both up- and down-link bands with which the relationship between the up- and down-link fading can be established. A power controlled carrier was transmitted to the ACTS satellite from a NASA operated ground station and the transponded signal was received at COMSAT Laboratories using a terminal that was routinely used to monitor the two ACTS beacon signals. The experiment ran for a period of approximately six months and the collected data were used to evaluate the performance of the power control system. A brief review of propagation factors involved in estimating the up-link fade using a beacon signal in the down-link band are presented. The power controller design and the experiment configuration are discussed. Results of the experiment are discussed.
Kimura, H; Kunitomo, F; Okita, S; Tojima, H; Tatsumi, K; Kuriyama, T; Hashizume, I; Honda, Y
1989-07-01
To evaluate the stability of the CO2-ventilation feedback system, we measured its open loop gain (G) in 12 patients with chronic obstructive pulmonary disease (COPD) and 15 control subjects. Then, we compared G to the conventional slope of the CO2-ventilation response line (S) and that of the metabolic hyperbola (SL). G was determined as the ratio of S to SL by applying external dead space of 250 and 500 ml. G, S and 1/SL in the control and the COPD were +17.1 +/- 7.2 (Mean +/- SD), 1.70 +/- 0.75 L.min-1.Torr-1 and -10.4 +/- 2.0 L-1.min.Torr, and -7.2 +/- 3.3, 0.48 +/- 0.27 L.min-1.Torr-1 and -16.1 +/- 6.4 L-1.min.Torr, respectively. G was significantly correlated with S in both groups, but that was not the case in 1/SL. The magnitude of G and S in COPD was about 42% and 28% of the control, indicating that G was maintained more stable than S. These data suggest that the decreased G in the COPD resulted from insufficient compensation of ventilatory drive, whereas 1/SL increased higher than the control. We conclude that G can be used to indicate the stability of the CO2-ventilation feedback system better than S.
Turbidity management during flushing-flows: A model for open-loop control
Fovet, Ophelie; Litrico, Xavier; Belaud, Gilles
2012-04-01
Fixed algae developments induce strong constraints for the management of open-channel networks. They cause clogging issues on hydraulic devices and can sometimes lead to water quality alteration. An original strategy to limit the algal biomass is to carry out regular flushes. A flush is performed by increasing the hydraulic shear conditions using the hydraulic structures of the canal. Consequently to the shear stress increase, a part of the fixed algae is detached, then re-suspended into the water column, and finally transported into the canal network. This leads to a peak of turbidity that needs to be controlled. The present paper proposes a quasi-linear model of the turbidity response to a discharge increase, that can be used for automatic controller design. The model parameters are identified on a real network. The calibration is based on continuous monitoring of water turbidity. Flushes are simulated on the whole branch and on an intermediate reach in order to test the ability of the model to simulate the propagation of a turbidity peak. Then, the model is used to develop an open-loop controller of turbidity for flush design. The efficiency of a flush will depend on its amplitude and duration. The design objective consists in maximizing the algae detachment without exceeding a maximal turbidity level, and using as little water as possible. The designed flush is finally tested on a nonlinear model.
Mobile Target Tracking Based on Hybrid Open-Loop Monocular Vision Motion Control Strategy
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Cao Yuan
2015-01-01
Full Text Available This paper proposes a new real-time target tracking method based on the open-loop monocular vision motion control. It uses the particle filter technique to predict the moving target’s position in an image. Due to the properties of the particle filter, the method can effectively master the motion behaviors of the linear and nonlinear. In addition, the method uses the simple mathematical operation to transfer the image information in the mobile target to its real coordinate information. Therefore, it requires few operating resources. Moreover, the method adopts the monocular vision approach, which is a single camera, to achieve its objective by using few hardware resources. Firstly, the method evaluates the next time’s position and size of the target in an image. Later, the real position of the objective corresponding to the obtained information is predicted. At last, the mobile robot should be controlled in the center of the camera’s vision. The paper conducts the tracking test to the L-type and the S-type and compares with the Kalman filtering method. The experimental results show that the method achieves a better tracking effect in the L-shape experiment, and its effect is superior to the Kalman filter technique in the L-type or S-type tracking experiment.
A Control Law Definition of the Open Loop Stepping Electric Drive
Directory of Open Access Journals (Sweden)
A. B. Krasovskii
2015-01-01
Full Text Available The paper considers an open loop stepping electric drive (SEP with electric crushing of a step and motor fed from the controlled current invertor which should meet the requirement that is to trial a free-form guided trajectory with a split-hair accuracy. It is shown that with traditional programmed control, when the SEP forms motor phase currents of identical amplitude and variable frequency proportional to the set speed of movement, there may be considerable errors reducing a trial accuracy of the set movement trajectory, dynamic indicators provoking oscillatory processes, and even loss of motor synchronism because influence on a dynamic moment of the motor is impossible.The paper offers and proves a new way to define a control algorithm adequate to drive parameters and programmed trajectory of movement, providing error minimization and thereby increasing trial accuracy of set parameters of movement and expanding dynamic capabilities of a drive. The essence of the offered way is to use a modified mathematical model of a drive in d,q coordinates with a motor fed by the current source. In this model a programmed trajectory of movement is chosen as an input action while solving the appropriate equations defines the necessary law of control. The paper describes a developed simulation model of the stepping electric drive in the environment of MATLAB – SIMULINK, which has been used to verify and prove an efficiency of the offered method to define a control law via typical examples.It is established that no error trial of set movement trajectory in case it has breaks (jogs is technically unfeasible, as it demands an infinitely high forcing voltage of the power supply to maintain the instant positive or negative phase shifts of currents formed in the motor windings.The obtained results can be used in designing programmable precision SEPs in robots, numerically controlled machine tools, and assembly equipment.
A new driving method for piezo deformable mirrors: open loop control and MOAO made easy
Ouattara, Issa; Gach, Jean-Luc; Amram, Philippe
2016-07-01
This paper presents the design and the realisation of a technique to attenuate the hysteresis nonlinear phenomenon of piezoelectric actuators. Piezoelectric actuator are widely utilised for deformable mirrors used for MOAO and power laser beam shaping techniques. The nonlinearities of piezo are usually iteratively compensa- ted using closed-loop set-ups. In open-loop control, the hysteresis and the creep of the piezo cannot be corrected, thus this nonlinearities must be removed or at least minimised. The concept has been demonstrated on high displacement Amplified Piezoelectric Actuators (APA) mounted in a Fabry-Perot interferometer. The hysteresis attenuation technique aims to assist the Fabry-Perots nano-positioning control system to attain its main scientific specification. In such system, each APA has a maximum stroke of 270 μm within a 170 V (-20 V to +150 V) range and is used to position a high reflective mirror plate. The Fabry-Perots nano-positioning control system is specified to limit the APAs positioning steady-state noise to 3nm rms, but the hysteresis limits the positioning accuracy. In order to attenuate hysteresis, a hybrid amplifier circuit built with a high power operational amplifier has been designed and applied for each APA. The experiments results show that the hysteresis effect has almost been eliminated, and consequently the positioning steady-state noise can significantly been reduced. Because of the excellent results of this hybrid amplifier, a patent application has been introduced in June 12, 2015 under number No.1555381 and is being reviewed now.
An assessment of overall open-loop "gain" of CO2-ventilation feedback control system in hypoxia.
Masuyama, H; Akiyama, S; Honda, Y
1985-01-01
Overall open-loop gain of the CO2-ventilation feedback control system in hypoxia (GHCO2) was determined on 8 male and one female healthy subjects. They breathed in a closed circuit, and were subjected to the progressive hypoxia test. This procedure was first conducted without dead space (DS), then with 250, 500, and finally 750 ml DS, consecutively. GHCO2 was calculated by dividing the slope of the CO2 response curve (S) by that of the metabolic hyperbola (SL). GHCO2 was considerably larger than the overall open-loop gain of the O2-ventilation feedback control system (GO2) previously obtained. This was ascribed to the facts that S was larger than the slope of the hypoxia response curve, and that the absolute value of SL in GHCO2 was smaller than that in GO2.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The open loop dynamic behaviors of internal thermally coupled distillation column with four different purities (low-,moderate-, high- and very high-purity) are studied. These dynamic behaviors are characterized by strong asymmetric non-linearity, high sensitivity to operation conditions change and distinct inverse response. With the increase of purity, these dynamic behaviors are intensified and become more complex, which easily lead to the mismatch between linear model and plant and also change the relationship between manipulated and controlled variables.
A model of open-loop control of equilibrium position and stiffness of the human elbow joint.
Kistemaker, Dinant A; Van Soest, Arthur J; Bobbert, Maarten F
2007-03-01
According to the equilibrium point theory, the control of posture and movement involves the setting of equilibrium joint positions (EP) and the independent modulation of stiffness. One model of EP control, the alpha-model, posits that stable EPs and stiffness are set open-loop, i.e. without the aid of feedback. The purpose of the present study was to explore for the elbow joint the range over which stable EPs can be set open-loop and to investigate the effect of co-contraction on intrinsic low-frequency elbow joint stiffness (K (ilf)). For this purpose, a model of the upper and lower arm was constructed, equipped with Hill-type muscles. At a constant neural input, the isometric force of the contractile element of the muscles depended on both the myofilamentary overlap and the effect of sarcomere length on the sensitivity of myofilaments to [Ca2+] (LDCS). The musculoskeletal model, for which the parameters were chosen carefully on the basis of physiological literature, captured the salient isometric properties of the muscles spanning the elbow joint. It was found that stable open-loop EPs could be achieved over the whole range of motion of the elbow joint and that K (ilf), which ranged from 18 to 42 N m.rad(-1), could be independently controlled. In the model, LDCS contributed substantially to K (ilf) (up to 25 N m.rad(-1)) and caused K (ilf) to peak at a sub-maximal level of co-contraction.
Game Theoretical Power Control for Open-Loop Overlaid Network MIMO Systems with Partial Cooperation
Yu, Hao; Lau, Vincent K N
2010-01-01
Network MIMO is considered to be a key solution for the next generation wireless systems in breaking the interference bottleneck in cellular systems. In the MIMO systems, open-loop transmission scheme is used to support mobile stations (MSs) with high mobilities because the base stations (BSs) do not need to track the fast varying channel fading. In this paper, we consider an open-loop network MIMO system with $K$ BSs serving K private MSs and $M^c$ common MS based on a novel partial cooperation overlaying scheme. Exploiting the heterogeneous path gains between the private MSs and the common MSs, each of the $K$ BSs serves a private MS non-cooperatively and the $K$ BSs also serve the $M^c$ common MSs cooperatively. The proposed scheme does not require closed loop instantaneous channel state information feedback, which is highly desirable for high mobility users. Furthermore, we formulate the long-term distributive power allocation problem between the private MSs and the common MSs at each of the $K$ BSs using...
Pradhan, Ranjan K; Feigl, Eric O; Gorman, Mark W; Brengelmann, George L; Beard, Daniel A
2016-06-01
A control system model was developed to analyze data on in vivo coronary blood flow regulation and to probe how different mechanisms work together to control coronary flow from rest to exercise, and under a variety of experimental conditions, including cardiac pacing and with changes in coronary arterial pressure (autoregulation). In the model coronary flow is determined by the combined action of a feedback pathway signal that is determined by the level of plasma ATP in coronary venous blood, an adrenergic open-loop (feed-forward) signal that increases with exercise, and a contribution of pressure-mediated myogenic control. The model was identified based on data from exercise experiments where myocardial oxygen extraction, coronary flow, cardiac interstitial norepinephrine concentration, and arterial and coronary venous plasma ATP concentrations were measured during control and during adrenergic and purinergic receptor blockade conditions. The identified model was used to quantify the relative contributions of open-loop and feedback pathways and to illustrate the degree of redundancy in the control of coronary flow. The results indicate that the adrenergic open-loop control component is responsible for most of the increase in coronary blood flow that occurs during high levels of exercise. However, the adenine nucleotide-mediated metabolic feedback control component is essential. The model was evaluated by predicting coronary flow in cardiac pacing and autoregulation experiments with reasonable fits to the data. The analysis shows that a model in which coronary venous plasma adenine nucleotides are a signal in local metabolic feedback control of coronary flow is consistent with the available data.
Morzinski, Katie; Gavel, Donald T; Grigsby, Bryant; Dillon, Daren; Reinig, Marc; Macintosh, Bruce A
2010-01-01
At the University of California's Lick Observatory, we have implemented an on-sky testbed for next-generation adaptive optics (AO) technologies. The Visible-Light Laser Guidestar Experiments instrument (ViLLaGEs) includes visible-light AO, a micro-electro-mechanical-systems (MEMS) deformable mirror, and open-loop control of said MEMS on the 1-meter Nickel telescope at Mt. Hamilton. In this paper we evaluate the performance of ViLLaGEs in open- and closed-loop control, finding that both control methods give equivalent Strehl ratios of up to ~ 7% in I-band and similar rejection of temporal power. Therefore, we find that open-loop control of MEMS on-sky is as effective as closed-loop control. Furthermore, after operating the system for three years, we find MEMS technology to function well in the observatory environment. We construct an error budget for the system, accounting for 130 nm of wavefront error out of 190 nm error in the science-camera PSFs. We find that the dominant known term is internal static error...
Morphing Wing-Tip Open Loop Controller and its Validation During Wind Tunnel Tests at the IAR-NRC
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Mohamed Sadok GUEZGUEZ
2016-09-01
Full Text Available In this project, a wing tip of a real aircraft was designed and manufactured. This wing tip was composed of a wing and an aileron. The wing was equipped with a composite skin on its upper surface. This skin changed its shape (morphed by use of 4 electrical in-house developed actuators and 32 pressure sensors. These pressure sensors measure the pressures, and further the loads on the wing upper surface. Thus, the upper surface of the wing was morphed using these actuators with the aim to improve the aerodynamic performances of the wing-tip. Two types of ailerons were designed and manufactured: one aileron is rigid (non-morphed and one morphing aileron. This morphing aileron can change its shape also for the aerodynamic performances improvement. The morphing wing-tip internal structure is designed and manufactured, and is presented firstly in the paper. Then, the modern communication and control hardware are presented for the entire morphing wing tip equipped with actuators and sensors having the aim to morph the wing. The calibration procedure of the wing tip is further presented, followed by the open loop controller results obtained during wind tunnel tests. Various methodologies of open loop control are presented in this paper, and results obtained were obtained and validated experimentally through wind tunnel tests.
A Bulk Control Circuit for Open-Loop Front-Ends for X-Ray Pixel Detectors
Grande, A.; Fiorini, C.; Fischer, P.; Porro, M.
2017-06-01
In this paper, we present a bulk control circuit to correct the chip-to-chip process variations of an open-loop nonlinear front-end (FE) for X-ray pixel detectors. Our study was carried out in the framework of the Depfet sensor with signal compression detector development for the European X-ray free electron laser. The presented circuit is capable to stabilize the FE response in presence of threshold voltage variations, acting on the bulk voltages of the FE's transistors and exploiting the body effect. The control circuit does not affect the noise performances of the FE. The working principle of the proposed control circuit and the first experimental results obtained with a first prototype realized in the 130-nm IBM technology are presented in this work.
Jiayuan He; Dingguo Zhang; Xinjun Sheng; Xiangyang Zhu
2015-08-01
This study presented a closed-loop adaptive calibration (CLAC) scheme where subjects could get instantaneous feedback of their movements and alter their motions immediately to update the model parameters to enhance its ability. The real-time performance was compared between the conventional open-loop calibration (OLC) and the presented CLAC based on three metrics (motion-selection time, motion-completion time and motion-completion rate). The CLAC performed slightly better than the OLC, but the difference was not significant. This was the first study designed to investigate the effects of CLAC for pattern recognition-based myoelectric control (discrete movement). The CLAC could be potentially applied in the multiuser interface to make the adaptation of the common model to a novel user efficiently and flexibly.
Multicore Based Open Loop Motor Controller Embedded System for Permanent Magnet Direct Current Motor
Directory of Open Access Journals (Sweden)
K. Baskaran
2012-01-01
Full Text Available Problem statement: In an advanced electronics world most of the applications are developed by microcontroller based embedded system. Approach: Multicore processor based motor controller was presented to improve the processing speed of the controller and improve the efficiency of the motor by maintaining constant speed. It was based on the combination of Cortex processor (Software core and Field Programmable Gate Arrays (FPGA, Hardware core. These multicore combination were help to design efficient low power motor controller. Results: A functional design of cortex processor and FPGA in this system was completed by using Actel libero IDE and IAR embedded IDE software PWM signal was generated by the proposed processor to control the motor driver circuit. All the function modules were programmed by Very-High-Speed Integrated Circuit Hardware Description Language (VHDL. The advantage of the proposed system was optimized operational performance and low power utility. Multicore processor was used to improve the speed of execution and optimize the performance of the controller. Conclusion: Without having the architectural concept of any motor we can control it by using this method.This is an low cost low power controller and easy to use. The simulation and experiment results verified its validity.
Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control
Kroics, K.; Sokolovs, A.
2016-08-01
The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM) but close to boundary conduction mode (BCM). The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.
Interleaved DC-DC Converter with Discrete Duty Cycle and Open Loop Control
Directory of Open Access Journals (Sweden)
Kroics K.
2016-08-01
Full Text Available The authors present the control principle of the multiphase interleaved DC-DC converter that can be used to vastly reduce output current ripple of the converter. The control algorithm can be easily implemented by using microcontroller without current loop in each phase. The converter works in discontinuous conduction mode (DCM but close to boundary conduction mode (BCM. The DC-DC converter with such a control algorithm is useful in applications that do not require precise current adjustment. The prototype of the converter has been built. The experimental results of the current ripple are presented in the paper.
Software system for open loop control of a synchrotron via special purpose consoles
Benincasa, G P; Heymans, P
1973-01-01
Most of the physics experiments performed at CERN require protons with an energy of 28 GeV. This is obtained in three stages: a linear accelerator, Linac, where the protons are created and brought to 50 Me V; next a first circular accelerator, Synchrotron Injector or Booster, where they reach 800 MeV; eventually the high energy synchrotron, PS (Proton Synchrotron), where they are accelerated to the required top energy. In contrast to the Linac and PS, the Booster has been designed very recently and is still running-in. From the beginning, it was intended to be fully computer controlled, i.e. acquisition and/or control of most of its variables. Whereas the computer control has always been implemented both at PS and Linac in parallel with an existing 'manual' control system, at the Booster its design could be imbedded within the study of the overall project. (5 refs).
Transonic Buffet Control on 3D Turbulent Wings using Fluidic Devices. Part 1: Open loop study
Dandois, J.; Dor, J; Molton, P.; Lepage, A.; Ternoy, F.; Coustols, E.
2013-01-01
This paper presents an overview of the work performed at Onera over the last decade on the control of the buffet phenomenon. This aerodynamic instability induces strong wall pressure fluctuations and as such limits aircraft envelope, consequently it is interesting to try to delay its onset, in order to improve aircraft performance, but also to provide more flexibility during the design phase. Several types of flow control have been investigated, either passive (mechanical vortex generators) o...
Coupled rotor-flexible fuselage vibration reduction using open loop higher harmonic control
Papavassiliou, I.; Friedmann, P. P.; Venkatesan, C.
1991-01-01
A fundamental study of vibration prediction and vibration reduction in helicopters using active controls was performed. The nonlinear equations of motion for a coupled rotor/flexible fuselage system have been derived using computer algebra on a special purpose symbolic computer facility. The trim state and vibratory response of the helicopter are obtained in a single pass by applying the harmonic balance technique and simultaneously satisfying the trim and the vibratory response of the helicopter for all rotor and fuselage degrees of freedom. The influence of the fuselage flexibility on the vibratory response is studied. It is shown that the conventional single frequency higher harmonic control is capable of reducing either the hub loads or only the fuselage vibrations but not both simultaneously. It is demonstrated that for simultaneous reduction of hub shears and fuselae vibrations a new scheme called multiple higher harmonic control is required.
Nonlinear Control of an Open-Loop Open-Winding Motor System with Modulated Converters
Directory of Open Access Journals (Sweden)
Oleschuk V.I.
2017-04-01
Full Text Available Purpose of this work - to provide wider control opportunities for multiphase open-end winding motor drive by modification of basic scheme of space-vector pulse-width modulation (PWM. It has been shown, that the proposed development of basic PWM scheme insures available solutions for realization of specific control dependences and modes of operation of adjustable speed ac drives with different types and kinds of loads. Suitable algorithms of PWM of converters of multiphase drive have been analyzed and compared. Extensive simulation studies have been executed for evaluation of performance and effectiveness of the proposed control strategy. Assessment of harmonic composition of the phase voltages of drive system with modified scheme of space-vector modulation has been done. Results of the executed simulations proved the fact, that the developed techniques of space-vector pulse-width modulation allow providing quarter-wave or half-wave symmetry of waveforms of the output voltage of six-phase adjustable speed drive systems during the analyzed non-standard modes and regimes of its operation.
Brydges, Ryan; Dubrowski, Adam
2009-10-01
Grasping behaviour involves the integration of current and historical knowledge about an object, a process that can be influenced by sensory uncertainty. In the present study, participants simultaneously interacted with a visual cue and a haptic cue before reaching to grasp a target object. The visual cue was either congruent (equal in size to haptic cue and target) or incongruent (larger than haptic cue and target). To enhance sensory uncertainty, we manipulated the proportion of congruent trials to be either 80 or 20%. We compared grasp kinematics and forces between congruent and incongruent trials and between the 20 and 80% proportion congruency groups. We also studied the effects of trial history by comparing the performance of congruent and incongruent trials preceded by either the same or opposite trial type. Proportion congruency did not affect temporal kinematics but did affect maximum grip aperture (MGA) as the 80% proportion congruency group used a greater MGA, regardless of trial type. For grasping forces, an interaction effect showed that the 20% proportion congruency group used a greater peak load force on congruent trials. Incongruent trials that followed congruent trials had decreased movement time, increased MGA and increased grasping forces, relative to those that followed incongruent trials. We interpret the data to suggest that the grasp control system integrates multisensory information using flexible, yet specific criteria regarding task constraints. The prevention of collision error (i.e., an inadequate MGA when contacting the target) may be one guiding principle in the control process.
Open-loop control of noise amplification in a separated boundary layer flow
Boujo, Edouard; Gallaire, François
2014-01-01
Linear optimal gains are computed for the subcritical two-dimensional separated boundary-layer flow past a bump. Very large optimal gain values are found, making it possible for small-amplitude noise to be strongly amplified and to destabilize the flow. The optimal forcing is located close to the summit of the bump, while the optimal response is the largest in the shear layer. The largest amplification occurs at frequencies corresponding to eigenvalues which first become unstable at higher Reynolds number. Nonlinear direct numerical simulations show that a low level of noise is indeed sufficient to trigger random flow unsteadiness, characterized here by large-scale vortex shedding. Next, a variational technique is used to compute efficiently the sensitivity of optimal gains to steady control (through source of momentum in the flow, or blowing/suction at the wall). A systematic analysis at several frequencies identifies the bump summit as the most sensitive region for control with wall actuation. Based on thes...
Energy Technology Data Exchange (ETDEWEB)
Klasen, M.; Sokoliuk, A. [TUeV Automotive GmbH, Muenchen (Germany)
2001-07-01
As a rule, the driver is the weakest link in the test set-up. In order to make dynamic driving tests more easily reproducible, the electronically controlled vehicle is recommended, which is used by TUeV Automotive for crash tests since about 10 years ago. [German] Das schwaechste Glied in der Kette einer Messung im Fahrversuch ist in der Regel der Versuchsfahrer. Um eine bessere Reproduzierbarkeit von fahrdynamischen Versuchen zu gewaehrleisten, bietet sich der Einsatz des ECV-Systems (Electronically Controlled Vehicle) als universelle Fahrmaschine an. Diese Technologie wird bei der TUeV Automotive bereits seit 10 Jahren bei Crashversuchen mit selbstfahrenden Fahrzeugen angewandt. (orig.)
Boujo, Edouard
2014-01-01
The two-dimensional backward-facing step flow is a canonical example of noise amplifier flow: global linear stability analysis predicts that it is stable, but perturbations can undergo large amplification in space and time as a result of non-normal effects. This amplification potential is best captured by optimal transient growth analysis, optimal harmonic forcing, or the response to sustained noise. In view of reducing disturbance amplification in these globally stable open flows, a variational technique is proposed to evaluate the sensitivity of stochastic amplification to steady control. Existing sensitivity methods are extended in two ways to achieve a realistic representation of incoming noise: (i) perturbations are time-stochastic rather than time-harmonic, (ii) perturbations are localised at the inlet rather than distributed in space. This allows for the identification of regions where small-amplitude control is the most effective, without actually computing any controlled flows. In particular, passive...
Smits-Engelsman, B.C.M.; Wilson, P.H.; Westenberg, Y.; Duysens, J.E.J.
2003-01-01
Thirty-two children with Developmental Coordination Disorder (DCD) and learning disabilities (LD) and their age-matched controls attending normal primary schools were investigated using kinematic movement analysis of fine-motor performance. Three hypotheses about the nature of the motor deficits obs
Smits-Engelsman, B.C.M.; Wilson, P.H.; Westenberg, Y.; Duysens, J.E.J.
2003-01-01
Thirty-two children with Developmental Coordination Disorder (DCD) and learning disabilities (LD) and their age-matched controls attending normal primary schools were investigated using kinematic movement analysis of fine-motor performance. Three hypotheses about the nature of the motor deficits obs
He, Jiayuan; Zhang, Dingguo; Jiang, Ning; Sheng, Xinjun; Farina, Dario; Zhu, Xiangyang
2015-08-01
Objective. Recent studies have reported that the classification performance of electromyographic (EMG) signals degrades over time without proper classification retraining. This problem is relevant for the applications of EMG pattern recognition in the control of active prostheses. Approach. In this study we investigated the changes in EMG classification performance over 11 consecutive days in eight able-bodied subjects and two amputees. Main results. It was observed that, when the classifier was trained on data from one day and tested on data from the following day, the classification error decreased exponentially but plateaued after four days for able-bodied subjects and six to nine days for amputees. The between-day performance became gradually closer to the corresponding within-day performance. Significance. These results indicate that the relative changes in EMG signal features over time become progressively smaller when the number of days during which the subjects perform the pre-defined motions are increased. The performance of the motor tasks is thus more consistent over time, resulting in more repeatable EMG patterns, even if the subjects do not have any external feedback on their performance. The learning curves for both able-bodied subjects and subjects with limb deficiencies could be modeled as an exponential function. These results provide important insights into the user adaptation characteristics during practical long-term myoelectric control applications, with implications for the design of an adaptive pattern recognition system.
Mettot, Clément; Sipp, Denis
2014-01-01
A fully discrete formalism is introduced to perform stability analysis of a turbulent compressible flow whom dynamics is modeled with the Reynolds-Averaged Navier-Stokes (RANS) equations. The discrete equations are linearized using finite differences and the Jacobian is computed using repeated evaluation of the residuals. Stability of the flow is assessed solving an eigenvalue problem. The sensitivity gradients which indicate regions of the flow where a passive control device could stabilize the unstable eigenvalues are defined within this fully discrete framework. Second order finite differences are applied to the discrete residual to compute the gradients. In particular, the sensitivity gradients are shown to be linked to the Hessian of the RANS equations. The introduced formalism and linearization method are generic: the code used to evaluate the residual of the RANS equations can be used in a black box manner, and the complex linearization of the Hessian is avoided. The method is tested on a two dimension...
The Improved Algorithm of the General Open-Loop Response Control%广义开环响应控制的改进算法
Institute of Scientific and Technical Information of China (English)
常青; 李言俊; 王亚欣
2000-01-01
The conventional algorithm of the general open-loop response control can hardly give attention to stability, robustness, speediness and anti-interference ability for it has less adjustable parameters. Aim at this problem, this paper puts forward two improved algorithms, and introduces one new adjustable parameter which has different intent compared with the original parameters, so the implement to the project is more easily. The result of the simulation has proved the efficiency of the algorithm.%传统的广义开环响应控制算法调节参数少，难以同时兼顾稳定性、鲁棒性、快速性和抗干扰性。为此提出了两种改进的算法，通过分别引入一个新的调节参数，使其与原有的调节参数具有不同的调节目的，更易于工程实现。仿真结果表明了该算法的有效性。
Wang, Yuan-Jay
2014-03-01
This paper proposes a novel alternative method to graphically compute all feasible gain and phase margin specifications-oriented robust PID controllers for open-loop unstable plus time delay (OLUPTD) processes. This method is applicable to general OLUPTD processes without constraint on system order. To retain robustness for OLUPTD processes subject to positive or negative gain variations, the downward gain margin (GM(down)), upward gain margin (GM(up)), and phase margin (PM) are considered. A virtual gain-phase margin tester compensator is incorporated to guarantee the concerned system satisfies certain robust safety margins. In addition, the stability equation method and the parameter plane method are exploited to portray the stability boundary and the constant gain margin (GM) boundary as well as the constant PM boundary. The overlapping region of these boundaries is graphically determined and denotes the GM and PM specifications-oriented region (GPMSOR). Alternatively, the GPMSOR characterizes all feasible robust PID controllers which achieve the pre-specified safety margins. In particular, to achieve optimal gain tuning, the controller gains are searched within the GPMSOR to minimize the integral of the absolute error (IAE) or the integral of the squared error (ISE) performance criterion. Thus, an optimal PID controller gain set is successfully found within the GPMSOR and guarantees the OLUPTD processes with a pre-specified GM and PM as well as a minimum IAE or ISE. Consequently, both robustness and performance can be simultaneously assured. Further, the design procedures are summarized as an algorithm to help rapidly locate the GPMSOR and search an optimal PID gain set. Finally, three highly cited examples are provided to illustrate the design process and to demonstrate the effectiveness of the proposed method.
Institute of Scientific and Technical Information of China (English)
徐尤南; 邓文强
2014-01-01
In this paper ,the hydraulic cylinder of shield thrust system is controlled by partition ,to reduce the complexity of the system and ensure the accuracy of control . The simulation analysis on the thrust hydraulic system is carried out by hydraulic simulation software AMESim ,which is controlled by open loop and closed loop respectively .The results show that :compared with open loop control , the pressure-flow closed loop control can effectively reduce the pressure and flow fluctuations , control the pressure and velocity in real time ,the control effect is better .%对盾构推进系统的液压缸采用分区控制，以达到降低系统复杂程度、保证控制精度的目的。用液压仿真软件AM ESim对推进液压系统进行仿真模拟分析，采用开环与闭环两种方式。仿真结果表明，压力流量闭环控制较开环控制可以有效减少压力和流量的波动，实时控制推进压力和推进速度，控制效果较好。
Simulation of the Open-loop and Closed-loop Control System Based on AMESim%基于AMESim压力开环与闭环控制系统研究
Institute of Scientific and Technical Information of China (English)
李新觉; 刘志刚; 余纯
2014-01-01
Based on the laboratory bench work of existing hydraulic schematics, AMESim models of the open-loop pressure control system and closed-loop pressure control system are established, then the results of simulation are an-alyzed in this paper. It's found that the closed-loop control system can be more stable than the open-loop control sys-tem. And it's proved that simulation results are effective by two comparative experiments.%基于实验室现有液压实验台工作原理图，通过分别建立压力开环控制和压力闭环控制系统的AMESim模型，以及所进行的仿真和分析，得出了闭环控制的系统能比开环控制的系统得到稳定精确的加载压力的结论。通过两种系统的控制对比实验，验证了仿真的结论。
Energy Technology Data Exchange (ETDEWEB)
Garcia Lopez, Manuel
2001-10-15
This work describes the design and implementation of an open loop speed controller for an induction motor. This controller is based on a DSP TMS320F240 chip from Texas Instruments. Speed control is achieved by maintaining the magnetic flux constant through the regularization of stator voltage/frequency relationship. Voltage and frequency variation are achieved using the strategy of pulse width modulation with space vectors. Hardware design is presented (current source and the printed circuit for the intelligent power module) and the software (control algorithms and the modulation strategy using space vectors). The algorithms given were implement using the TMS320F240 language. [Spanish] Este trabajo describe el diseno y la implementacion de un control de la velocidad en lazo abierto de un motor de induccion, basado en el DSP TMS320F240 de Texas Instruments. El control de la velocidad se logra manteniendo el flujo en el entre hierro constante, lo cual es realizado al regular el valor de la relacion voltaje/frecuencia en el estator. La variacion del voltaje y la frecuencia se realiza utilizando la estrategia de modulacion del ancho de los pulsos con vectores espaciales. Se presenta el diseno de los circuitos (fuente de corriente continua y circuito impreso para el modulo inteligente de potencia) y de los programas (algoritmos de control y de la estrategia de modulacion con vectores espaciales) necesarios que se utilizaron durante la implementacion del accionamiento del motor. Los algoritmos dados fueron implementados en el lenguaje ensamblador del TMS320F240.
Digitalization optical open loop test system for fiber optic gyroscope
Institute of Scientific and Technical Information of China (English)
ZHANG Deng-wei; SHU Xiao-wu; MU Xu-dong; LIU Cheng
2006-01-01
In order to receive and process the open loop signal from fiber optic gyroscopes speedily,stably and expediently,and to realize the amity interface between human and machine,a digital system that can convert GPIB (general purpose interface bus ) parallel bus into Universal Serial Bus is developed.All the interface functions of GP1B and the hardware system are realized through FPGA.With a digital sampling and processing system designed with VC++ in Windows platform,the real-time controlling procedure,high-speed receiving and sending data can be carried out,and the results can be displayed too.So the design of the system is flexible,the reliability and the stability are improved,error rate is no more than 10-11,the highest bit rate is 8 MB/s and the open loop detection system for optic fiber gyros achieves standardization and complete digitalization simultaneously.
2011-03-01
controlling a system. Hagen and Demuth describe the neural network controller as a function approximator [38]. In this case of a neural network, the...Martin T. Hagan and Howard B. Demuth , "Neural Networks for Control," in American Control Conference, San Diego, 1999. [39] Joseph Matthews
A True Open-Loop Synchronization Technique
DEFF Research Database (Denmark)
Golestan, Saeed; Vidal, Ana; Yepes, Alejandro G.
2016-01-01
to worsen in the presence of frequency drifts. To deal with this problem, two approaches are often recommended in the literature: Adapting OLS techniques to grid frequency variations by feeding back the frequency estimated by them or using the frequency estimated by a secondary frequency detector...... in a parallel manner. In the presence of the frequency feedback loop, nevertheless, the OLS technique may not be truly open-loop, which makes a deep study of stability necessary. Using the secondary frequency detector, on the other hand, increases the computational effort and implementation complexity. Another...
Closed/Open-loop Sub-optimal Control of Structures Based on Output Feedbacks%基于输出反馈的建筑结构闭开环次优控制
Institute of Scientific and Technical Information of China (English)
宋刚; 谭川; 陈果
2015-01-01
对传统的结构抗震闭开环控制算法进行改进。基于地面运动自回归模型，采用Kalman滤波利用可以量测到的地面加速度激励对未来时段即将发生的地面加速度激励进行预估，并在微分方程的求解中引入精确高效的精细积分算法。考虑到实际控制中量测全部状态变量的困难，改进算法仅需量测部分状态变量。数值仿真表明，基于输出反馈的闭开环次优控制策略能大大降低结构的地震响应。%Most recent studies have been based on the application of linear quadratic regulator con-trol to earthquake-excited structures.In linear quadratic regulator control problems,the objective function is defined as the integral of a quadratic expression in the control interval with respect to structural states and control vectors,and the optimal regulator can be derived using Pontryagin’ s maximum principle or Bellman’s method of dynamic programming.In traditional linear quad-ratic regulator control problems,the Riccati equation is obtained without considering the earth-quake excitation term.To optimize control and satisfy the optimality condition,in this study,we propose a new closed/open-loop control strategy for structures under earthquake excitation.We derive an analytical solution to a linear regulator problem for structural control without neglecting unknown disturbances.The optimal regulator depends on both the state and disturbances.The solution for this closed/open-loop control requires the knowledge of the earthquake in the control interval,which is approximated based on the real-time prediction of near-future earthquake exci-tation using the Kalman filtering technique.Earthquake excitation is modeled as an autoregressive process.The prediction algorithm can predict seismic excitation in the near future with high accu-racy,although it lacks prediction accuracy for more distant future events.Considering the meas-urement difficulty of all state variables
TeGrotenhuis, Ward Evan
2013-11-05
A drying apparatus is disclosed that includes a drum and an open-loop airflow pathway originating at an ambient air inlet, passing through the drum, and terminating at an exhaust outlet. A passive heat exchanger is included for passively transferring heat from air flowing from the drum toward the exhaust outlet to air flowing from the ambient air inlet toward the drum. A heat pump is also included for actively transferring heat from air flowing from the passive heat exchanger toward the exhaust outlet to air flowing from the passive heat exchanger toward the drum. A heating element is also included for further heating air flowing from the heat pump toward the drum.
Institute of Scientific and Technical Information of China (English)
朱道伟; 谢辉; 严英
2012-01-01
混合动力车辆一般采用基于荷电状态(SOC)闭环的控制策略,对蓄电池组进行频繁充电,使SOC维持在较高水平,影响制动能量的回收,从而导致燃油经济性不理想.为此,利用BP神经网络并结合城市公交运行特点,提出SOC开环控制策略,对公交车未来站点间的运行工况进行预测,减少蓄电池组的充电次数,降低蓄电池组的荷电状态.试验表明,采用该控制策略可以显著降低电池组充电时间和次数,有利于制动能量的回收,百公里油耗降低了3％.%The conventional strategy of hybrid electric vehicle was based on the state of charge (SOC) closed-loop which charged the battery frequently to sustain a high-level SOC and decreased the fuel efficiency because the energy from the regenerative braking couldn't be stored any more. SOC open-loop control strategy was proposed using the BP neural network and considering the trait of city bus to predict the next driving cycles between two stops in short future. Experiment result shows that the control strategy is useful to decrease charging times and time-period, which improve fuel efficiency by 3% higher than the vehicle on the route with the control strategy of SOC closed-loop because of enhanced regenerative braking energy.
Tiny Open-Loop Atmospheric Sensing Technique Project
National Aeronautics and Space Administration — The TOAST instrument is an open-loop processor of GPS navigation signals. The electronics fits on a single 10 cm square card with RF components and digital...
IDENTIFICATION OF BOTH CLOSED- AND OPEN-LOOP STOCHASTIC SYSTEM WHILE STABILIZING IT
Institute of Scientific and Technical Information of China (English)
CHEN Hanfu (Han-Fu Chen)
2002-01-01
This paper proposes a recursive algorithm estimating coefficients of thc linear stochastic control system (ARX system) driven by a martingale difference sequence, while adaptively stabilizing the system without introducing external excitation signal. The system is allowed to be unstable and of nonminimum-phase. The estimates derived for the coefficients of both closed-loop and open-loop systems are strongly consistent.
On Stability of Open-Loop Operation without Rotor Information for Brushless DC Motors
Directory of Open Access Journals (Sweden)
Zhong Wu
2014-01-01
Full Text Available Open-loop operation mode is often used to control the Brushless DC Motors (BLDCMs without rotor position sensors when the back electromotive force (EMF is too weak due to the very low rotor velocity. The rotor position information is not necessary in this mode and the stator windings are supplied with voltages under a certain ratio of the amplitude to the frequency. However, the rotor synchronization will be destroyed once if the commutation instant is inappropriate. In order to improve the reliability of the open-loop operation mode, a dynamic equation is established to represent the synchronization error between the rotor and the stator. Thereafter, the stability of the open-loop control mode is analyzed by using Lyapunov indirect method. Theoretical analysis indicates that the open-loop control mode is asymptotically stable only when the commutation instant of the stator current lags behind the ideal one suitably. Finally, theoretical analysis is verified through the experimental results of a certain BLDCM.
Open-loop frequency response for a chaotic masking system
Institute of Scientific and Technical Information of China (English)
Huang Xian-Gao; Yu Pei; Huang Wei
2006-01-01
In this paper, a new numerical simulation approach is proposed for the study of open-loop frequency response of a chaotic masking system. Using Chua's circuit and the Lorenz system as illustrative examples, we have shown that one can employ chaos synchronization to separate the feedback network from a chaotic masking system, and then use numerical simulation to obtain the open-loop synchronization response, the phase response, and the amplitude response of a chaotic masking system. Based on the analysis of the frequency response, we have also proved that changing the amplitude of the exciting (input) signal within normal working domain does not influence the frequency response of the chaotic masking system. The new numerical simulation method developed in this paper can be extended to consider the open-loop frequency response of other systems described by differential or difference equations.
OPEN-LOOP FOG SIGNAL TESTING AND WAVELET ELIMINATING NOISE
Institute of Scientific and Technical Information of China (English)
ZHUYun-zhao; WANGShun-ring; MIAOLing-juan; WANGBo
2005-01-01
An open-loop fiber optic gyro (FOG) testing system is designed. The noise characteristic of open-loop fiber optic gyro signals is analyzed. The wavelet eliminating noise method is discussed and compared with other methods, such as smoothing and low-pass filter methods. Results indicate that the wavelet eliminating noise method can satisfy the measuring demand of the FOG weak output signal with noise disturbing. The wavelet analysis method can efficiently eliminate the noise and reserve the information of the signal. The eliminating noise effect of using different wavelet base functions is compared. The effectiveness of multiresolution wavelet analyses of eliminating noise is proved by experimental results.
Real-time open-loop frequency response analysis of flight test data
Bosworth, J. T.; West, J. C.
1986-01-01
A technique has been developed to compare the open-loop frequency response of a flight test aircraft real time with linear analysis predictions. The result is direct feedback to the flight control systems engineer on the validity of predictions and adds confidence for proceeding with envelope expansion. Further, gain and phase margins can be tracked for trends in a manner similar to the techniques used by structural dynamics engineers in tracking structural modal damping.
Open-loop experiments of resonator micro-optic gyro
Institute of Scientific and Technical Information of China (English)
ZHANG Xu-lin; ZHOU Ke-jiang
2009-01-01
An open-loop resonator micro-optic gyro (R-MOG) with a 6 cm-long waveguide-type ring resonator is set up using the phase modulation spectroscopy technique. In the experiment, according to the test parameters of the resonator, the shot-noise-limited sensitivity is estimated to be 1.07×10-4 rad/s. From the test demodulation signal, the gyro dynamic range of ±7.0×103 rad/s is obtained. Using different phase modulation frequencies, the open-loop gyro output signal is observed when the equivalent gyro rotation is applied to the aconstic-optical modulators (AOMs). The sensitivity of the R-MOG can be increased by some countermeasures against system noise.
Institute of Scientific and Technical Information of China (English)
梁延旗; 胡一峰; 朱磊
2014-01-01
In power system, static var compensator plays an important role in improving line power factor and the quality of system voltage, but when with the startup power source the static var compensator can hardly have a good compensation effect. The control strategy of static var compensator in startup power source was studied, a method based on open loop control was put forward and the scientificity and rationality of the control strategy was proved through simulation.%在电力系统中，无功补偿装置主要用于提高线路功率因数，改善系统电压质量的作用，但是，在含启备变供电环境下，无功补偿装置想要取得良好的补偿效果就极其困难。对含启备变系统中无功补偿装置的控制策略进行了研究，提出了一种基于开环控制的方法，并通过仿真，验证了控制策略的科学性与合理性。
Low cost, practical, all-digital open-loop fiber-optic gyroscope
Institute of Scientific and Technical Information of China (English)
Yuanhong Yang(杨远洪); Weixu Zhang(张惟叙); Jing Ma(马静); Xinjun Chen(陈新军)
2003-01-01
A novel all-digital scheme for open-loop fiber-optic gyroscope (FOG), where only two key points of outputwave were digitized directly, has been proposed. A control equation, with which the modulation depthof PZT modulator is stable when setting the modulation depth as 4.35 and a calculation equation, withwhich the Sagnac phase can be worked out, are derived. A modulation depth control and an automaticcorrelation sampling and a gain control technology were induced. A photo-type FOG was made and tested.The good performance was achieved.
Environmental impacts of open loop geothermal system on groundwater
Kwon, Koo-Sang; Park, Youngyun; Yun, Sang Woong; Lee, Jin-Yong
2013-04-01
Application of renewable energies such as sunlight, wind, rain, tides, waves and geothermal heat has gradually increased to reduce emission of CO2 which is supplied from combustion of fossil fuel. The geothermal energy of various renewable energies has benefit to be used to cooling and heating systems and has good energy efficiency compared with other renewable energies. However, open loop system of geothermal heat pump system has possibility that various environmental problems are induced because the system directly uses groundwater to exchange heat. This study was performed to collect data from many documents such as papers and reports and to summarize environmental impacts for application of open loop system. The environmental impacts are classified into change of hydrogeological factors such as water temperature, redox condition, EC, change of microbial species, well contamination and depletion of groundwater. The change of hydrogeological factors can induce new geological processes such as dissolution and precipitation of some minerals. For examples, increase of water temperature can change pH and Eh. These variations can change saturation index of some minerals. Therefore, dissolution and precipitation of some minerals such as quartz and carbonate species and compounds including Fe and Mn can induce a collapse and a clogging of well. The well contamination and depletion of groundwater can reduce available groundwater resources. These environmental impacts will be different in each region because hydrogeological properties and scale, operation period and kind of the system. Therefore, appropriate responses will be considered for each environmental impact. Also, sufficient study will be conducted to reduce the environmental impacts and to improve geothermal energy efficiency during the period that a open loop system is operated. This work was supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning
Open-loop thermochemical cycles for the production of hydrogen
Energy Technology Data Exchange (ETDEWEB)
Conger, W.L.
1979-01-01
The concept of open-loop thermochemical cycles (cycles which have additional or other feedstocks than water and produce materials in addition to hydrogen and oxygen) is introduced. Preliminary analysis of possible feedstocks available indicates substantial quantities of hydrogen could possibly be produced through open-cycles. The advantages of open-cycles include the conversion of unwanted waste products to useful products while producing hydrogen. A compilation of open processes which would have SO/sub 2/ in addition to water as feedstock and which would produce sulfuric acid in addition to hydrogen and oxygen is given.
Study of the Open Loop and Closed Loop Oscillator Techniques
Energy Technology Data Exchange (ETDEWEB)
Imel, George R. [Idaho State Univ., Pocatello, ID (United States); Baker, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riley, Tony [Knolls Atomic Power Lab. (KAPL), Schenectady, NY (United States); Langbehn, Adam [Puget Sound Naval Base, Bremerton, WA (United States); Aryal, Harishchandra [Idaho State Univ., Pocatello, ID (United States); Benzerga, M. Lamine [Idaho State Univ., Pocatello, ID (United States)
2015-04-11
This report presents the progress and completion of a five-year study undertaken at Idaho State University of the measurement of very small worth reactivity samples comparing open and closed loop oscillator techniques.The study conclusively demonstrated the equivalency of the two techniques with regard to uncertainties in reactivity values, i.e., limited by reactor noise. As those results are thoroughly documented in recent publications, in this report we will concentrate on the support work that was necessary. For example, we describe in some detail the construction and calibration of a pilot rod for the closed loop system. We discuss the campaign to measure the required reactor parameters necessary for inverse-kinetics. Finally, we briefly discuss the transfer of the open loop technique to other reactor systems.
Energy Technology Data Exchange (ETDEWEB)
Reinschke, K. [Technische Univ. Dresden (Germany). Inst. fuer Regelungs- und Streuerungstheorie
2006-07-01
After the introduction of bachelor and master studies in Germany, new training concepts are required. In the field of engineering, there is a lack of research-oriented German-language textbooks which are also suited for further training of professionally experienced engineers. The author addresses readers with good prior knowledge of mathematics and application-oriented basic training in open-loop and control-loop engineering who intend to deepen their knowledge of the methods of control of linear time-continuous processes. The reader is enabled to apply the mathematical tools of linear system theory for control purposes. Unavoidable uncertainties in the modelling of control paths are considered. The focus is on function theoretical and algebraic aspects which enable the design of robust stabilising controllers as well as trajectory control and follow-up control and also the time-continuous treatment of scanning control loops. There are many examples to illustrate the general laws that are presented. (orig.) [German] Die Einfuehrung von gestuften Bachelor- und Master-Studiengaengen erfordert neue Ausbildungskonzepte. Fuer die Master- und Promotionsstudiengaenge der Ingenieure mangelt es bisher an forschungsorientierten deutschsprachigen Lehrwerken, die zugleich auch zur Fortbildung von berufserfahrenen Ingenieuren geeignet sind. Dieses Buch traegt zur Behebung dieses Mangels bei. Der Autor wendet sich an Leser, die eine gute mathematische Vorbildung und eine anwendungsorientierte Grundausbildung in Regelungs- und Steuerungstechnik abgeschlossen haben und nun tiefer in die Methoden der Regelung und Steuerung von linearen zeitkontinuierlichen Prozessen eindringen wollen. Der Leser wird befaehigt, die mathematischen Werkzeuge der linearen Systemtheorie fuer regelungstechnische Zwecke einzusetzen. Bei der Modellierung von Regelstrecken werden die unvermeidlichen Unbestimmtheiten beruecksichtigt. Im Zentrum stehen die funktionentheoretischen und algebraischen
Importance of Hydrogeological Conditions on Open-loop Geothermal System
Park, D.; Bae, G.; Kim, S.; Lee, K.
2013-12-01
The open-loop geothermal system has been known as an eco-friendly, energy-saving, and cost-efficient alternative for the cooling and heating of buildings with directly using the relatively stable temperature of groundwater. Thus, hydrogeological properties of aquifer, such as hydraulic conductivity and storage, must be important in the system application. The study site is located near Han-river, Korea, and because of the well-developed alluvium it might be a typical site appropriate to this system requiring an amount of groundwater. In this study, the first objective of numerical experiments was to find the best distributions of pumping and injection wells suitable to the hydrogeological conditions of the site for the efficient and sustainable system operation. The aquifer has a gravel layer at 15m depth below the ground surface and the river and the agricultural field, which may be a potential contaminant source, are located at the west and east sides, respectively. Under the general conditions that the regional groundwater flows from the east to the river, the locally reversed well distribution, locating the pumping well at upgradient and the injection well at downgradient of the regional flow, was most sustainable. The gravel layer with high hydraulic conductivity caused a little drawdown despite of an amount of pumping and allowed to stably reinject the used groundwater in all the cases, but it provided a passage transferring the injected heat to the pumping well quickly, particularly in the cases locating the injection well at the upgradient. This thermal interference was more severe in the cases of the short distance between the wells. The high conductive layer is also a reason that the seasonal role conversion of wells for the aquifer thermal energy storage was ineffective in this site. Furthermore, the well distribution vertical to the regional groundwater flow was stable, but not best, and, thus, it may be a good choice in the conditions that the regional
Open-Loop Wide-Bandwidth Phase Modulation Techniques
Directory of Open Access Journals (Sweden)
Nitin Nidhi
2011-01-01
Full Text Available The ever-increasing growth in the bandwidth of wireless communication channels requires the transmitter to be wide-bandwidth and power-efficient. Polar and outphasing transmitter topologies are two promising candidates for such applications, in future. Both these architectures require a wide-bandwidth phase modulator. Open-loop phase modulation presents a viable solution for achieving wide-bandwidth operation. An overview of prior art and recent approaches for phase modulation is presented in this paper. Phase quantization noise cancellation was recently introduced to lower the out-of-band noise in a digital phase modulator. A detailed analysis on the impact of timing and quantization of the cancellation signal is presented. Noise generated by the transmitter in the receive band frequency poses another challenge for wide-bandwidth transmitter design. Addition of a noise transfer function notch, in a digital phase modulator, to reduce the noise in the receive band during phase modulation is described in this paper.
Open-loop frequency response analysis of a wind turbine using a high-order linear aeroelastic model
DEFF Research Database (Denmark)
Sønderby, Ivan Bergquist; Hansen, Morten Hartvig
2014-01-01
Wind turbine controllers are commonly designed on the basis of low-order linear models to capture the aeroelastic wind turbine response due to control actions and disturbances. This paper characterizes the aeroelastic wind turbine dynamics that influence the open-loop frequency response from gene......-minimum phase zeros below the frequency of the first drivetrain mode. To correctly predict the non-minimum phase zeros, it is essential to include lateral tower and blade flap degrees of freedom. Copyright © 2013 John Wiley & Sons, Ltd....
Applications of Bifurcation Methods to F-181HARV Open-loop Dynamics in Landing Configuration
Directory of Open Access Journals (Sweden)
Nandan Kumar Sinha
2002-04-01
Full Text Available Over the past two decades, bifurcation and continuation methods have emerged as efficient tools for prediction, and control of flight instabilities. Bifurcation phenomena have been associated with nonlinear behaviour of aircraft in actual flight tests, and the critical control combinations, which signify onset of instabilities, have been identified for almost all generations of modern fighter aircraft. A standard bifurcation analysis procedure has been used in the past. In this paper, the bifurcation theory, relevant to preliminary bifurcation analysis of nonlinear aircraft dynamics, has been introduced, and a stepswise methodology used in a standard bifurcation analysis procedure has been illustrated with an application to open-loop dynamics of an F- 18/HARV model in landing configuration. Further, an example manoeuvre is constructed, and numerical time simulations of an F-18/HARV model in this manoeuvre is carried out to validate the predictions from the bifurcation analysis. Numerical time simulation results confirm the onset of nonlinear behaviour at critical control combinations identified in bifurcation analysis of the aircraft model. Thus, bifurcation methods, in conjunction with selective numerical simulations, can be extremely useful in the design, development, evaluation, and flight training phases of a fighter aircraft development programme.
Open-Loop Flight Testing of COBALT GN&C Technologies for Precise Soft Landing
Carson, John M., III; Amzajerdian, Farzin; Seubert, Carl R.; Restrepo, Carolina I.
2017-01-01
A terrestrial, open-loop (OL) flight test campaign of the NASA COBALT (CoOperative Blending of Autonomous Landing Technologies) platform was conducted onboard the Masten Xodiac suborbital rocket testbed, with support through the NASA Advanced Exploration Systems (AES), Game Changing Development (GCD), and Flight Opportunities (FO) Programs. The COBALT platform integrates NASA Guidance, Navigation and Control (GN&C) sensing technologies for autonomous, precise soft landing, including the Navigation Doppler Lidar (NDL) velocity and range sensor and the Lander Vision System (LVS) Terrain Relative Navigation (TRN) system. A specialized navigation filter running onboard COBALT fuzes the NDL and LVS data in real time to produce a precise navigation solution that is independent of the Global Positioning System (GPS) and suitable for future, autonomous planetary landing systems. The OL campaign tested COBALT as a passive payload, with COBALT data collection and filter execution, but with the Xodiac vehicle Guidance and Control (G&C) loops closed on a Masten GPS-based navigation solution. The OL test was performed as a risk reduction activity in preparation for an upcoming 2017 closed-loop (CL) flight campaign in which Xodiac G&C will act on the COBALT navigation solution and the GPS-based navigation will serve only as a backup monitor.
The effect of proximity on open-loop accommodation responses measured with pinholes.
Morrison, K A; Seidel, D; Strang, N C; Gray, L S
2010-07-01
Open-loop accommodation levels were measured in 41 healthy, young subjects using a Shin-Nippon SRW-5000 autorefractor in the three viewing conditions: a small physical pinhole pupil (SP), an optically projected pinhole in Maxwellian view (MV) and in the dark (DF). The target viewed through the pinholes was a high-contrast letter presented at 0 D vergence in a +5 D Badal lens system. Overall, results showed that SP open-loop accommodation levels were significantly higher than MV and DF levels. Subjects could be divided into two distinct subgroups according to their response behaviour: responders to the proximal effect of the small physical pinhole (SP accommodation > MV accommodation) and non-responders to the proximal effect of the small physical pinhole (SP accommodation approximately MV accommodation). Correlation analysis demonstrated that open-loop accommodation for both pinhole conditions was correlated with DF for the responders, while for the non-responders SP and MV accommodation were correlated, but were not related to DF accommodation. This suggests that under open-loop conditions some individuals' accommodation levels are mainly affected by proximal and cognitive factors (responders) while others are guided primarily by the presence of the more distal target (non-responders). In conclusion, MV reduces the proximal effect of the physical pinhole and produces open-loop accommodation responses which are more consistent than SP and DF responses.
High-sensitivity open-loop electronics for gravimetric acoustic-wave-based sensors.
Rabus, David; Friedt, Jean-Michel; Ballandras, Sylvain; Martin, Gilles; Carry, Emile; Blondeau-Patissier, Virginie
2013-06-01
Detecting chemical species in gas phase has recently received an increasing interest mainly for security control, trying to implement new systems allowing for extended dynamics and reactivity. In this work, an open-loop interrogation strategy is proposed to use radio-frequency acoustic transducers as micro-balances for that purpose. The resulting system is dedicated to the monitoring of chemical compounds in gaseous or liquid-phase state. A 16 Hz standard deviation is demonstrated at 125 MHz, with a working frequency band in the 60 to 133 MHz range, answering the requirements for using Rayleigh- and Love-wave-based delay lines operating with 40-μm acoustic wavelength transducers. Moreover, this electronic setup was used to interrogate a high-overtone bulk acoustic wave resonator (HBAR) microbalance, a new sensor class allowing for multi-mode interrogation for gravimetric measurement improvement. The noise source still limiting the system performance is due to the analog-to-digital converter of the microcontroller, thus leaving open degrees-of-freedom for improving the obtained results by optimizing the voltage reference and board layout. The operation of the system is illustrated using a calibrated galvanic deposition at the surface of Love-wave delay lines to assess theoretical predictions of their gravimetric sensitivity and to compare them with HBAR-based sensor sensitivity.
Development of miniature HTSC wide-band filter with open-loop resonators
Institute of Scientific and Technical Information of China (English)
ZHANG TianLiang; YANG Kai; NING JunSong; BU ShiRong; LIU JuanXiu; LUO ZhengXiang
2008-01-01
The strong electric and magnetic coupled novel HTSC (high temperature superconductor) open-loop mierostrip resonators are studied in this report and the traditional structure of open-loop resonators is improved. A miniature wide-band HTSC bandpass filter is developed by the novel structure, which is fabricated on YBCO/LaAIO3/BCO substrate with dimensions of 14.8×9.6 mm2. This filter is tested at 77K, and the specifications are that the center frequency is 2230 MHz, the bandwidth is 455 MHz, and the best insertion loss is 0.14 dB in passband.
A novel open-loop tracking strategy for photovoltaic systems.
Alexandru, Cătălin
2013-01-01
This paper approaches a dual-axis equatorial tracking system that is used to increase the photovoltaic efficiency by maximizing the degree of use of the solar radiation. The innovative aspect in the solar tracker design consists in considering the tracking mechanism as a perturbation for the DC motors. The goal is to control the DC motors, which are perturbed with the motor torques whose computation is based on the dynamic model of the mechanical structure on which external forces act. The daily and elevation angles of the PV module represent the input parameters in the mechanical device, while the outputs transmitted to the controller are the motor torques. The controller tuning is approached by a parametric optimization process, using design of experiments and response surface methodology techniques, in a multiple regression. The simulation and experimental results demonstrate the operational performance of the tracking system.
A Novel Open-Loop Tracking Strategy for Photovoltaic Systems
Directory of Open Access Journals (Sweden)
Cătălin Alexandru
2013-01-01
Full Text Available This paper approaches a dual-axis equatorial tracking system that is used to increase the photovoltaic efficiency by maximizing the degree of use of the solar radiation. The innovative aspect in the solar tracker design consists in considering the tracking mechanism as a perturbation for the DC motors. The goal is to control the DC motors, which are perturbed with the motor torques whose computation is based on the dynamic model of the mechanical structure on which external forces act. The daily and elevation angles of the PV module represent the input parameters in the mechanical device, while the outputs transmitted to the controller are the motor torques. The controller tuning is approached by a parametric optimization process, using design of experiments and response surface methodology techniques, in a multiple regression. The simulation and experimental results demonstrate the operational performance of the tracking system.
Darestani Farahani, N.; Abbasi Davani, F.
2016-02-01
The formulation of a multi-input single-output closed-loop subspace method for system identification has been employed for the purpose of obtaining control-relevant model of the open loop response for plasma vertical movement in the Damavand tokamak. Such a model is particularly well suited for the robust controller design. The method described in this paper is a kind of worst-case identification technique, aiming to minimize the error between the identified model and the true plant. The accuracy of the estimation of the plant dynamics has been tested by different experiments. The fitness of the identified model around the defined operating point has been more than 90%, and compared to the physical-based model, it has better root mean squared error (RMSE) measure of the goodness of fitting.
Keymeulen, Didier; Ferguson, Michael I.; Fink, Wolfgang; Oks, Boris; Peay, Chris; Terrile, Richard; Cheng, Yen; Kim, Dennis; MacDonald, Eric; Foor, David
2005-01-01
We propose a tuning method for MEMS gyroscopes based on evolutionary computation to efficiently increase the sensitivity of MEMS gyroscopes through tuning. The tuning method was tested for the second generation JPL/Boeing Post-resonator MEMS gyroscope using the measurement of the frequency response of the MEMS device in open-loop operation. We also report on the development of a hardware platform for integrated tuning and closed loop operation of MEMS gyroscopes. The control of this device is implemented through a digital design on a Field Programmable Gate Array (FPGA). The hardware platform easily transitions to an embedded solution that allows for the miniaturization of the system to a single chip.
Analytic solution of Riccati equations occurring in open-loop Nash multiplayer differential games
Directory of Open Access Journals (Sweden)
L. Jódar
1992-01-01
Full Text Available In this paper we present explicit analytic solutions of coupled Riccati matrix differential systems appearing in open-loop Nash games. Two different cases are considered. Firstly, by means of appropriate algebraic transformations the problem is decoupled so that an explicit solution of the problem is available. The second is based on the existence of a solution of a rectangular Riccati type algebraic matrix equation associated with the problem.
Larsen, T.; Doll, J. C.; Loizeau, F.; Hosseini, N.; Peng, A. W.; Fantner, G. E.; Ricci, A. J.; Pruitt, B. L.
2017-04-01
Electrothermal actuators have many advantages compared to other actuators used in micro-electro-mechanical systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using step inputs due to its intrinsic thermal time constant. However, the use of pre-shaped input signals offers a route for reducing the rise time of these actuators by orders of magnitude. We started with an electrothermally actuated cantilever having an initial 10-90% rise time of 85 μs in air and 234 μs in water for a standard open-loop step input. We experimentally characterized the linearity and frequency response of the cantilever when operated in air and water, allowing us to obtain transfer functions for the two cases. We used these transfer functions, along with functions describing desired reduced rise-time system responses, to numerically simulate the required input signals. Using these pre-shaped input signals, we improved the open-loop 10-90% rise time from 85 μs to 3 μs in air and from 234 μs to 5 μs in water, an improvement by a factor of 28 and 47, respectively. Using this simple control strategy for MEMS electrothermal actuators makes them an attractive alternative to other high speed micromechanical actuators such as piezoelectric stacks or electrostatic comb structures which are more complex to design, fabricate, or operate.
Tiwari, Abhinav; Igoshin, Oleg A
2012-10-01
Biochemical regulatory networks governing diverse cellular processes such as stress-response, differentiation and cell cycle often contain coupled feedback loops. We aim at understanding how features of feedback architecture, such as the number of loops, the sign of the loops and the type of their coupling, affect network dynamical performance. Specifically, we investigate how bistability range, maximum open-loop gain and switching times of a network with transcriptional positive feedback are affected by additive or multiplicative coupling with another positive- or negative-feedback loop. We show that a network's bistability range is positively correlated with its maximum open-loop gain and that both quantities depend on the sign of the feedback loops and the type of feedback coupling. Moreover, we find that the addition of positive feedback could decrease the bistability range if we control the basal level in the signal-response curves of the two systems. Furthermore, the addition of negative feedback has the capacity to increase the bistability range if its dissociation constant is much lower than that of the positive feedback. We also find that the addition of a positive feedback to a bistable network increases the robustness of its bistability range, whereas the addition of a negative feedback decreases it. Finally, we show that the switching time for a transition from a high to a low steady state increases with the effective fold change in gene regulation. In summary, we show that the effect of coupled feedback loops on the bistability range and switching times depends on the underlying mechanistic details.
Two-stage open-loop velocity compensating method applied to multi-mass elastic transmission system
Directory of Open Access Journals (Sweden)
Zhang Deli
2014-02-01
Full Text Available In this paper, a novel vibration-suppression open-loop control method for multi-mass system is proposed, which uses two-stage velocity compensating algorithm and fuzzy I + P controller. This compensating method is based on model-based control theory in order to provide a damping effect on the system mechanical part. The mathematical model of multi-mass system is built and reduced to estimate the velocities of masses. The velocity difference between adjacent masses is calculated dynamically. A 3-mass system is regarded as the composition of two 2-mass systems in order to realize the two-stage compensating algorithm. Instead of using a typical PI controller in the velocity compensating loop, a fuzzy I + P controller is designed and its input variables are decided according to their impact on the system, which is different from the conventional fuzzy PID controller designing rules. Simulations and experimental results show that the proposed velocity compensating method is effective in suppressing vibration on a 3-mass system and it has a better performance when the designed fuzzy I + P controller is utilized in the control system.
Analytical solution for a class of linear quadratic open-loop Nash game with multiple players
Institute of Scientific and Technical Information of China (English)
Xiaohong NIAN; Zhisheng DUAN; Wenyan TANG
2006-01-01
In this paper, the Nash equilibria for differential games with multiple players is studied. A method for solving the Riccati-type matrix differential equations for open-loop Nash strategy in linear quadratic game with multiple players is presented and analytical solution is given for a type of differential games in which the system matrixcan be diagonalizable. As the special cases, the Nash equilibria for some type of differential games with particular structure is studied also, and some results in previous literatures are extended. Finally, a numerical example is given to illustrate the effectiveness of the solution procedure.
The Life Cycle Evaluation Model of External Diseconomy of Open-loop Supply Chain
Liu, Qian; Hu, Tianjun
2017-08-01
In recent years, with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased, people began to use the method of recycling on waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method, comparative analysis through the case. This paper also concludes that the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.
Open-Loop Flight Testing of COBALT Navigation and Sensor Technologies for Precise Soft Landing
Carson, John M., III; Restrepo, Caroline I.; Seubert, Carl R.; Amzajerdian, Farzin; Pierrottet, Diego F.; Collins, Steven M.; O'Neal, Travis V.; Stelling, Richard
2017-01-01
An open-loop flight test campaign of the NASA COBALT (CoOperative Blending of Autonomous Landing Technologies) payload was conducted onboard the Masten Xodiac suborbital rocket testbed. The payload integrates two complementary sensor technologies that together provide a spacecraft with knowledge during planetary descent and landing to precisely navigate and softly touchdown in close proximity to targeted surface locations. The two technologies are the Navigation Doppler Lidar (NDL), for high-precision velocity and range measurements, and the Lander Vision System (LVS) for map-relative state esti- mates. A specialized navigation filter running onboard COBALT fuses the NDL and LVS data in real time to produce a very precise Terrain Relative Navigation (TRN) solution that is suitable for future, autonomous planetary landing systems that require precise and soft landing capabilities. During the open-loop flight campaign, the COBALT payload acquired measurements and generated a precise navigation solution, but the Xodiac vehicle planned and executed its maneuvers based on an independent, GPS-based navigation solution. This minimized the risk to the vehicle during the integration and testing of the new navigation sensing technologies within the COBALT payload.
Directory of Open Access Journals (Sweden)
Stefano L. Russo
2010-01-01
Full Text Available Problem statement: The increasing diffusion of low-enthalpy geothermal open-loop Groundwater Heat Pumps (GWHP providing buildings air conditioning requires a careful assessment of the overall effects on groundwater system, especially in the urban areas. The impact on the groundwater temperature in the surrounding area of the re-injection well is directly linked to the aquifer properties. Physical processes affecting heat transport within an aquifer include advection (or convection and hydrodynamic thermodispersion (diffusion and mechanical dispersion. If the groundwater flows, the advective components tend to dominate the heat transfer process within the aquifer and the diffusion can be considered negligible. This study illustrates the experimental results derived from the groundwater monitoring in the surrounding area of an injection well connected to an open-loop GWHP plant which has been installed in the "Politecnico di Torino" (NW Italy for cooling some of the university buildings. Groundwater pumping and injection interfere only with the upper unconfined aquifer. Approach: After the description of the hydrogeological setting the authors examined the data deriving from multiparameter probes installed inside the pumping well (P2, the injection well (P4 and a downgradient piezometer (S2. Data refers to the summer 2009. To control the aquifer thermal stratification some multi-temporal temperature logs have been performed in the S2. Results: After the injection of warm water in P4 the plume arrived after 30 days in the S2. That delay is compatible with the calculated plume migration velocity (1.27 m d-1 and their respective distance (35 m. The natural temperature in the aquifer due to the switching-off of the GWHP plant has been reached after two month. The Electrical Conductivity (EC values tend to vary out of phase with the temperature. The temperature logs in the S2 highlighted a thermal stratification in the aquifer due to a low vertical
Ruan, Hang; Li, Jian; Zhang, Lei; Long, Teng
2015-08-28
For vehicle positioning with Global Navigation Satellite System (GNSS) in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N₀) varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA) is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N₀. The novel Equivalent Weighted Pseudo Range Error (EWPRE) is raised to obtain the optimal code search grid sizes for different C/N₀. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area.
Characterization of Site for Installing Open Loop Ground Source Heat Pump System
Yun, S. W.; Park, Y.; Lee, J. Y.; Yi, M. J.; Cha, J. H.
2014-12-01
This study was conducted to understand hydrogeological properties of site where open loop ground source heat pump system will be installed and operated. Groundwater level and water temperature were hourly measured at the well developed for usage of open loop ground source heat pump system from 11 October 2013 to 8 January 2014. Groundwater was sampled in January and August 2013 and its chemical and isotopic compositions were analyzed. The bedrock of study area is the Jurassic granodiorite that mainly consists of quartz (27.9 to 46.8%), plagioclase (26.0 to 45.5%), and alkali feldspar (9.5 to 18.7%). The groundwater level ranged from 68.30 to 68.94 m (above mean sea level). Recharge rate was estimated using modified watertable fluctuation method and the recharge ratios was 9.1%. The water temperature ranged from 14.8 to 15.0oC. The vertical Increase rates of water temperature were 1.91 to 1.94/100 m. The water temperature showed the significant seasonal variation above 50 m depth, but had constant value below 50 m depth. Therefore, heat energy of the groundwater can be used securely in open loop ground source heat pump system. Electrical conductivity ranged from 120 to 320 µS/cm in dry season and from 133 to 310 µS/cm in wet season. The electrical conductivity gradually decreased with depth. In particular, electrical conductivity in approximately 30 m depth decreased dramatically (287 to 249 µS/cm) in wet season. The groundwater was Ca-HCO3 type. The concentrations of dissolved components did not show the vertically significant variations from 0 to 250 m depth. The δ18O and δD ranged from -9.5 to -9.4‰ and from -69 to -68‰. This work is supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).
Modeling Open-Loop MEMS Tunneling Accelerometer Based on Circular Plate
Directory of Open Access Journals (Sweden)
Hossein Jodat Kordlar
2007-04-01
Full Text Available In this paper open-loop MEMS tunneling accelerometer was modeled based on a clamped micro circular plate with a tip tunneling at its centre. Mechanical behavior of the micro plate was studied deriving governing equation based on classic Kirchhoff thin plate theory and it was discretized using Galerkin method. Dynamic response of the proposed accelerometer due to step and harmonic external excitation was studied and the magnitude of the applied acceleration was identified by measuring of the changing of tunneling current. Obtained results show that the proposed tunneling accelerometer very sensitive and it can be measure acceleration with very high resolution but very small gap of tip tunneling limit the range of measurable acceleration.
ENERGY AND ENVIRONMENTAL ANALYSIS OF AN OPEN-LOOP GROUND-WATER HEAT PUMP SYSTEM IN AN URBAN AREA
Directory of Open Access Journals (Sweden)
Giorgia Baccino
2010-01-01
Full Text Available In this paper a multidisciplinary methodology for analyzing the opportunities for exploitation of open-loop groundwater heat pump is proposed. The approach starts from a model for calculation of a time profile of thermal requirements (heat and domestic hot water. This curve is then coupled with a model of the control system in order to determine the heat pump operation, which includes its energy performances (primary energy consumption as well as profiles of water discharge to the aquifer in terms of mass flow rate and temperature. Then the thermo-fluid dynamics of the aquifer is performed in order to determine the system impact on the environment as on possible other systems. The application to a case study in the Piedmont region, in Italy, is proposed. Energy analysis of the system shows that ground-water heat pumps constitute an interesting option in areas with small housing density, where there is not district heating. In comparison with typical heating/cooling systems, environmental benefits are related with reduction in global emissions. These benefits may be significantly enhanced using renewables as the primary energy source to produce electricity. The analysis also shows that possible issues related with the extension of the subsurface thermal plume may arise in the case of massive utilization of this technology.
A digital open-loop Doppler processing prototype for deep-space navigation
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
A prototype based on digital radio technology with associated open-loop Doppler signal processing techniques has been developed to measure a spacecraft’s line-of-sight velocity. The prototype was tested in China’s Chang’E-1 lunar mission relying on S-band telemetry signals transmitted by the sat-ellite,with results showing that the residuals had a RMS value of ～3 mm/s (1σ ) using 1-sec integration,which is consistent with the Chinese conventional USB (Unified S-Band) tracking system. Such preci-sion is mainly limited by the short-term stability of the atomic (e.g. rubidium) clock at the uplink ground station. It can also be improved with proper calibration to remove some effects of the transmission media (such as solar plasma,troposphere and ionosphere),and a longer integration time (e.g. down to 0.56 mm/s at 34 seconds) allowed by the spacecraft dynamics. The tracking accuracy can also be in-creased with differential methods that may effectively remove most of the long-term drifts and some of the short-term uncertainties of the uplink atomic clock,thereby further reducing the residuals to the 1 mm/s level. Our experimental tracking data have been used in orbit determination for Chang’E-1,while other applications (such as the upcoming YH-1 Mars orbiter) based on open-loop Doppler tracking will be initiated in the future. Successful application of the prototype to the Chang’E-1 mission in 2008 is believed to have great significance for China’s future deep space exploration.
Directory of Open Access Journals (Sweden)
Arvind Venkataraman
2013-01-01
Full Text Available Purpose: To assess the visual outcome and rotational stability of single-piece open loop toric Intra Ocular Lens (IOL in a clinical setting. Materials and Methods: In a prospective study, 122 eyes of 77 patients were followed up for a period of 12 months after cataract surgery with toric open loop IOL implantation. The pre-operative markings for the position of incision and IOL placement were done under slit lamp by anterior stromal puncture. The visual acuity, refraction, and IOL position were assessed at day 1, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. Results: The mean age of the cohort was 56 yrs (S.D. 13.88; range 16 to 87 years. The mean pre-operative cylinder of corneal astigmatism was 1.37 D. (SD 0.79, range 1.0 to 5.87 D. Mean post-operative refractive cylinder was 0.36 D (SD 0.57, range 0 to 1.50 D at 12 months. Ninety-seven percent of the eyes were within 1 D of residual astigmatism. Ninety-four percent of patients had uncorrected visual acuity of 20/30 or better. Four eyes required IOL repositioning due to rotation. At 12 months, 96.7% of the IOLs were within 10 degrees of the target axis. There was no rotation seen after 6 months. Conclusion: Toric IOLs are very effective and consistent in correcting astigmatism during the cataract surgery. IOL rotation happens mostly within a month of surgery, and if significant, requires early repositioning.
A digital open-loop Doppler processing prototype for deep-space navigation
Institute of Scientific and Technical Information of China (English)
JIAN NianChuan; QIU Shi; FUNG Lai-Wo; ZHANG Hua; WANG Zhen; GOU Wei; SHANG Kun; ZHANG SuJun; WANG MingYuan; SHI Xian; PING JingSong; YAN JianGuo; TANG GeShi; LIU JunZe
2009-01-01
A prototype based on digital radio technology with associated open-loop Doppler signal processing techniques has been developed to measure a spacecraft's line-of-sight velocity. The prototype was tested in China's Chang'E-1 lunar mission relying on S-band telemetry signals transmitted by the satellite, with results showing that the residuals had a RMS value of ～3 mm/s (1 σ ) using 1-sec integration, which is consistent with the Chinese conventional USB (Unified S-Band) tracking system. Such precision is mainly limited by the short-term stability of the atomic (e.g. Rubidium) clock at the uplink ground station. It can also be improved with proper calibration to remove some effects of the transmission media (such as solar plasma, troposphere and ionosphere), and a longer integration time (e.g. Down to 0.56 mm/s at 34 seconds) allowed by the spacecraft dynamics. The tracking accuracy can also be increased with differential methods that may effectively remove most of the long-term drifts and some of the short-term uncertainties of the uplink atomic clock, thereby further reducing the residuals to the 1 mm/s level. Our experimental tracking data have been used in orbit determination for Chang'E-1, while other applications (such as the upcoming YH-1 Mars orbiter) based on open-loop Doppler tracking will be initiated in the future. Successful application of the prototype to the Chang'E-1 mission in 2008 is believed to have great significance for China's future deep space exploration.
All-digital signal-processing open-loop fiber-optic gyroscope with enlarged dynamic range.
Wang, Qin; Yang, Chuanchuan; Wang, Xinyue; Wang, Ziyu
2013-12-15
We propose and realize a new open-loop fiber-optic gyroscope (FOG) with an all-digital signal-processing (DSP) system where an all-digital phase-locked loop is employed for digital demodulation to eliminate the variation of the source intensity and suppress the bias drift. A Sagnac phase-shift tracking method is proposed to enlarge the dynamic range, and, with its aid, a new open-loop FOG, which can achieve a large dynamic range and high sensitivity at the same time, is realized. The experimental results show that compared with the conventional open-loop FOG with the same fiber coil and optical devices, the proposed FOG reduces the bias instability from 0.259 to 0.018 deg/h, and the angle random walk from 0.031 to 0.006 deg/h(1/2), moreover, enlarges the dynamic range to ±360 deg/s, exceeding the maximum dynamic range ±63 deg/s of the conventional open-loop FOG.
Directory of Open Access Journals (Sweden)
Fernando Martínez
2011-01-01
Full Text Available Se presenta un nuevo emulador para turbinas eólicas de paso fijo, que permite realizar pruebas de laboratorio de los sistemas de control de los generadores asociados a las turbinas eólicas. La novedad del emulador consiste en utilizar un esquema en lazo abierto. El emulador consiste en el acoplamiento en serie de los siguientes elementos: una fuente de tensión de CC, una resistencia de potencia y un motor de CC. La modificación de la tensión en CC tiene el mismo efecto que la variación de la velocidad del viento en una turbina eólica. Se incluyen: 1 los fundamentos teóricos del emulador, 2 la realización de simulaciones utilizando las aplicaciones informáticas Excel y Matlab/Simulink, y 3 los resultados experimentales obtenidos en una bancada de máquinas eléctricas. Se comprueba que el emulador permite reproducir las curvas de potencia mecánica de una turbina de paso fijo, aunque con ciertas limitaciones a baja velocidad de giro.A novel emulator for fixed pitch wind turbines that allows laboratory testing of the generator control systems associated with the turbines is presented. The novelty of the emulator is to be an open loop scheme. The emulator consists of the coupling in series of a source of DC voltage, a power resistance and a DC motor. The modification of the input DC voltage has the same effect as the variation of wind speed in a fixed pitch wind turbine. This article includes: 1 theoretical foundations of the emulator, 2 Excel and Simulink simulations, and 3 experimental results obtained in a bench of electrical machines. It is shown that the emulator can reproduce the mechanical power curves of a fixed pitch turbine, but with certain limitations at low speed.
Jeon, W. H.; Kim, N.; Lee, J. Y.
2014-12-01
This study aims to evaluate the influence of open loop ground source heat pump systems operation on hydrological conditions of aquifer. Test bed is located in Chuncheon, Korea. The step drawdown test was conducted in five stages for 300 minutes. The variation of groundwater levels by open loop ground source heat pump systems operation was estimated using Visual MODFLOW. Transmissivity ranged from 2.02×10-4 to 9.36×10-4, and storage coefficient ranged from 0.00067 to 0.021. The amount of optimum bleeding was calculated to be 240 m3/day. When bleeding will be 50, 90, 240 and 450 m3/day for 5 years, groundwater levels may decrease 1.84, 3.31, 8.89 and 17.0 m, respectively. If the amount of bleeding is 50 m3/day, the influence of bleeding will not reach the boundary regions of the Soyang River after 5 years. Regarding the open loop ground source heat pump system installed at the test bed, the amount of optimum bleeding in accordance with the stand are proposed by the government is 90 m3/day, which is 20% of the 450 m3/day circulation quantity of the system. However, if continuous bleeding of more than 90 m3/day occurs, then the radius of influence is expected to reach the boundary regions of the Soyang River after 5 years. These results indicate that amount of optimum bleeding differ in each open loop ground soured heat pump system. Therefore, the debate for the amount of optimum bleeding in open loop ground source heat pump systems is demanded. This work is supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).
Directory of Open Access Journals (Sweden)
Hang Ruan
2015-08-01
Full Text Available For vehicle positioning with Global Navigation Satellite System (GNSS in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N0 varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N0. The novel Equivalent Weighted Pseudo Range Error (EWPRE is raised to obtain the optimal code search grid sizes for different C/N0. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area.
Open Loop Heat Pipe Radiator Having a Free-Piston for Wiping Condensed Working Fluid
Weinstein, Leonard M. (Inventor)
2015-01-01
An open loop heat pipe radiator comprises a radiator tube and a free-piston. The radiator tube has a first end, a second end, and a tube wall, and the tube wall has an inner surface and an outer surface. The free-piston is enclosed within the radiator tube and is capable of movement within the radiator tube between the first and second ends. The free-piston defines a first space between the free-piston, the first end, and the tube wall, and further defines a second space between the free-piston, the second end, and the tube wall. A gaseous-state working fluid, which was evaporated to remove waste heat, alternately enters the first and second spaces, and the free-piston wipes condensed working fluid from the inner surface of the tube wall as the free-piston alternately moves between the first and second ends. The condensed working fluid is then pumped back to the heat source.
An open-loop RFOG based on harmonic division technique to suppress LD's intensity modulation noise
Ying, Diqing; Wang, Zeyu; Mao, Jianmin; Jin, Zhonghe
2016-11-01
A harmonic division technique is proposed for an open-loop resonator fiber optic gyro (RFOG) to suppress semiconductor laser diode's (LD's) intensity modulation noise. The theoretical study indicates the RFOG with this technique is immune to the intensity noise. The simulation and experimental results show this technique would lead to a diminished linear region, which still could be acceptable for an RFOG applied to low rotation rate detection. The tests for the gyro output signal are carried out with/without noise suppressing methods, including the harmonic division technique and previously proposed signal compensation technique. With the harmonic division technique at the rotation rate of 10 deg/s, the stability of gyro output signal is improved from 1.07 deg/s to 0.0361 deg/s, whose noise suppressing ratio is more than 3 times as that of the signal compensation technique. And especially, a 3.12 deg/s signal jump is significantly removed with the harmonic division technique; in contrast, a residual 0.36 deg/s signal jump still exists with the signal compensation technique. It is concluded the harmonic division technique does work in intensity noise suppressing under dynamic condition, and it is superior to the signal compensation technique.
Open-loop correction for an eddy current dominated beam-switching magnet
Koseki, K.; Nakayama, H.; Tawada, M.
2014-04-01
A beam-switching magnet and the pulsed power supply it requires have been developed for the Japan Proton Accelerator Research Complex. To switch bunched proton beams, the dipole magnetic field must reach its maximum value within 40 ms. In addition, the field flatness should be less than 5 × 10-4 to guide each bunched beam to the designed orbit. From a magnetic field measurement by using a long search coil, it was found that an eddy current in the thick endplates and laminated core disturbs the rise of the magnetic field. The eddy current also deteriorates the field flatness over the required flat-top period. The measured field flatness was 5 × 10-3. By using a double-exponential equation to approximate the measured magnetic field, a compensation pattern for the eddy current was calculated. The integrated magnetic field was measured while using the newly developed open-loop compensation system. A field flatness of less than 5 × 10-4, which is an acceptable value, was achieved.
Open-loop correction for an eddy current dominated beam-switching magnet
Energy Technology Data Exchange (ETDEWEB)
Koseki, K., E-mail: kunio.koseki@kek.jp; Nakayama, H.; Tawada, M. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)
2014-04-15
A beam-switching magnet and the pulsed power supply it requires have been developed for the Japan Proton Accelerator Research Complex. To switch bunched proton beams, the dipole magnetic field must reach its maximum value within 40 ms. In addition, the field flatness should be less than 5 × 10{sup −4} to guide each bunched beam to the designed orbit. From a magnetic field measurement by using a long search coil, it was found that an eddy current in the thick endplates and laminated core disturbs the rise of the magnetic field. The eddy current also deteriorates the field flatness over the required flat-top period. The measured field flatness was 5 × 10{sup −3}. By using a double-exponential equation to approximate the measured magnetic field, a compensation pattern for the eddy current was calculated. The integrated magnetic field was measured while using the newly developed open-loop compensation system. A field flatness of less than 5 × 10{sup −4}, which is an acceptable value, was achieved.
Performance enhancement of open loop gas recovery process by centrifugal separation of gases
Kalmani, S. D.; Joshi, A. V.; Bhattacharya, S.; Hunagund, P. V.
2016-11-01
The proposed INO-ICAL detector [1] is going to be instrumented with 28800 RPCs (Resistive Plate Chamber). These RPCs (2 × 2 m2 size) will consist of two glass electrodes separated by 2 mm and will use a gas mixture of Freon R134a, isobutane and sulphur hexafluoride (in the ratio of 95.3:4.5:0.2). An Open Ended System (OES), in which the gas mixture is vented to the atmosphere after a single passage through the detector, is most commonly used for small detector setups. However, OES cannot be used with the INO-ICAL detector due to reasons of cost and pollution. It is necessary, therefore, to recirculate the gas mixture in a closed loop. In a Closed Loop gas System (CLS) [2] the gas mixture is purified and recirculated after flowing through the RPC. The impurities which get accumulated in the gas mixture due to leaks or formation of radicals are removed by suitable filters. The Open Loop System (OLS) [3] is based on the separation and recovery of major gas components after passage of the gas mixture through the RPCs. and has the advantage that it does not need filters for removal of impurities. However a CLS is found to be more efficient than OLS in the recovery of gases in the mixture. In this paper we discuss centrifugal separation [4] as a technique to extract major gas constituents and use this technique to improve the efficiency of OLS. Results from preliminary trial runs are reported.
Realisierung eines verzerrungsarmen Open-Loop Klasse-D Audio-Verstärkers mit SB-ZePoC
Directory of Open Access Journals (Sweden)
O. Schnick
2007-06-01
Full Text Available In den letzten Jahren hat die Entwicklung von Klasse-D Verstärkern für Audio-Anwendungen ein vermehrtes Interesse auf sich gezogen. Eine Motivation hierfür liegt in der mit dieser Technik extrem hohen erzielbaren Effizienz von über 90%. Die Signale, die Klasse-D Verstärker steuern, sind binär. Immer mehr Audio-Signale werden entweder digital gespeichert (CD, DVD, MP3 oder digital übermittelt (Internet, DRM, DAB, DVB-T, DVB-S, GMS, UMTS, weshalb eine direkte Umsetzung dieser Daten in ein binäres Steuersignal ohne vorherige konventionelle D/A-Wandlung erstrebenswert erscheint.
Die klassischen Pulsweitenmodulationsverfahren führen zu Aliasing-Komponenten im Audio-Basisband. Diese Verzerrungen können nur durch eine sehr hohe Schaltfrequenz auf ein akzeptables Maß reduziert werden. Durch das von der Forschungsgruppe um Prof. Mathis vorgestellte SB-ZePoC Verfahren (Zero Position Coding with Separated Baseband wird diese Art der Signalverzerrung durch Generierung eines separierten Basisbands verhindert. Deshalb können auch niedrige Schaltfrequenzen gewählt werden. Dadurch werden nicht nur die Schaltverluste, sondern auch Timing-Verzerrungen verringert, die durch die nichtideale Schaltendstufe verursacht werden. Diese tragen einen großen Anteil zu den gesamten Verzerrungen eines Klasse-D Verstärkers bei. Mit dem SB-ZePoC Verfahren lassen sich verzerrungsarme Open-Loop Klasse-D Audio-Verstärker realisieren, die ohne aufwändige Gegenkopplungsschleifen auskommen.
Class-D amplifiers are suiteble for amplification of audio signals. One argument is their high efficiency of 90% and more. Today most of the audio signals are stored or transmitted in digital form. A digitally controlled Class-D amplifier can be directly driven with coded (modulated data. No separate D/A conversion is needed. Classical modulation schemes like Pulse-Width-Modulation (PWM cause aliasing. So a very high switching rate is required to minimize the
Open-loop GPS signal tracking at low elevation angles from a ground-based observation site
Beyerle, Georg; Zus, Florian
2017-01-01
A 1-year data set of ground-based GPS signal observations aiming at geometric elevation angles below +2° is analysed. Within the "GLESER" measurement campaign about 2600 validated setting events were recorded by the "OpenGPS" open-loop tracking receiver at an observation site located at 52.3808° N, 13.0642° E between January and December 2014. The measurements confirm the feasibility of open-loop signal tracking down to geometric elevation angles of -1 to -1.5° extending the corresponding closed-loop tracking range by up to 1°. The study is based on the premise that observations of low-elevation events by a ground-based receiver may serve as test cases for space-based radio occultation measurements, even if the latter proceed at a significantly faster temporal scale. The results support the conclusion that the open-loop Doppler model has negligible influence on the derived carrier frequency profile for strong signal-to-noise density ratios above about 30 dB Hz. At lower signal levels, however, the OpenGPS receiver's dual-channel design, which tracks the same signal using two Doppler models differing by 10 Hz, uncovers a notable bias. The repeat patterns of the GPS orbit traces in terms of azimuth angle reveal characteristic signatures in both signal amplitude and Doppler frequency with respect to the topography close to the observation site. Mean vertical refractivity gradients, extracted from ECMWF meteorological fields, correlate weakly to moderately with observed signal amplitude fluctuations at geometric elevation angles between +1 and +2°. Results from multiple phase screen simulations support the interpretation that these fluctuations are at least partly produced by atmospheric multipath; at negative elevation angles diffraction at the ground surface seems to contribute.
Controllability of Quantum Systems
Schirmer, S G; Solomon, A I
2003-01-01
An overview and synthesis of results and criteria for open-loop controllability of Hamiltonian quantum systems obtained using Lie group and Lie algebra techniques is presented. Negative results for open-loop controllability of dissipative systems are discussed, and the superiority of closed-loop (feedback) control for quantum systems is established.
A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system.
Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A
2005-11-01
While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.
Open-loop GPS signal tracking at low elevation angles from a ground-based observation site
Beyerle, Georg; Zus, Florian
2016-04-01
For more than a decade space-based global navigation satellite system (GNSS) radio occultation (RO) observations are used by meteorological services world-wide for their numerical weather prediction models. In addition, climate studies increasingly rely on validated GNSS-RO data sets of atmospheric parameters. GNSS-RO profiles typically cover an altitude range from the boundary layer up to the upper stratosphere; their highest accuracy and precision, however, are attained at the tropopause level. In the lower troposphere, multipath ray propagation tend to induce signal amplitude and frequency fluctuations which lead to the development and implementation of open-loop signal tracking methods in GNSS-RO receiver firmwares. In open-loop mode the feed-back values for the carrier tracking loop are derived not from measured data, but from a Doppler frequency model which usually is extracted from an atmospheric climatology. In order to ensure that this receiver-internal parameter set, does not bias the carrier phase path observables, dual-channel open-loop GNSS-RO signal tracking was suggested. Following this proposal the ground-based "GLESER" (GPS low-elevation setting event recorder) campaign was established. Its objective was to disproof the existence of model-induced frequency biases using ground-based GPS observations at very low elevation angles. Between January and December 2014 about 2600 validated setting events, starting at geometric elevation angles of +2° and extending to -1°… - 1.5°, were recorded by the single frequency "OpenGPS" GPS receiver at a measurement site located close to Potsdam, Germany (52.3808°N, 13.0642°E). The study is based on the assumption that these ground-based observations may be used as proxies for space-based RO measurements, even if the latter occur on a one order of magnitude faster temporal scale. The "GLESER" data analysis shows that the open-loop Doppler model has negligible influence on the derived frequency profile
de La Bernardie, Jérôme; de Dreuzy, Jean-Raynald; Bour, Olivier; Thierion, Charlotte; Ausseur, Jean-Yves; Lesuer, Hervé; Le Borgne, Tanguy
2016-04-01
Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (energy storage at these shallow depths is still remaining very challenging because of the complexity of fractured media. The purpose of this study is to test the possibility of efficient thermal energy storage in shallow fractured rocks with a single well semi open loop heat exchanger (standing column well). For doing so, a simplified numerical model of fractured media is considered with few fractures. Here we present the different steps for building the model and for achieving the sensitivity analysis. First, an analytical and dimensional study on the equations has been achieved to highlight the main parameters that control the optimization of the system. In a second step, multiphysics software COMSOL was used to achieve numerical simulations in a very simplified model of fractured media. The objective was to test the efficiency of such a system to store and recover thermal energy depending on i) the few parameters controlling fracture network geometry (size and number of fractures) and ii) the frequency of cycles used to store and recover thermal energy. The results have then been compared to reference shallow geothermal systems already set up for porous media. Through this study, relationships between structure, heat exchanges and storage may be highlighted.
Choi, Junil; Love, David J.; Bidigare, Patrick
2014-10-01
The concept of deploying a large number of antennas at the base station, often called massive multiple-input multiple-output (MIMO), has drawn considerable interest because of its potential ability to revolutionize current wireless communication systems. Most literature on massive MIMO systems assumes time division duplexing (TDD), although frequency division duplexing (FDD) dominates current cellular systems. Due to the large number of transmit antennas at the base station, currently standardized approaches would require a large percentage of the precious downlink and uplink resources in FDD massive MIMO be used for training signal transmissions and channel state information (CSI) feedback. To reduce the overhead of the downlink training phase, we propose practical open-loop and closed-loop training frameworks in this paper. We assume the base station and the user share a common set of training signals in advance. In open-loop training, the base station transmits training signals in a round-robin manner, and the user successively estimates the current channel using long-term channel statistics such as temporal and spatial correlations and previous channel estimates. In closed-loop training, the user feeds back the best training signal to be sent in the future based on channel prediction and the previously received training signals. With a small amount of feedback from the user to the base station, closed-loop training offers better performance in the data communication phase, especially when the signal-to-noise ratio is low, the number of transmit antennas is large, or prior channel estimates are not accurate at the beginning of the communication setup, all of which would be mostly beneficial for massive MIMO systems.
Programmable Relaxor Open-Loop Mirrors Using Imaging Spatial Encoder (PROMISE) Project
National Aeronautics and Space Administration — Future advanced telescopes require active mirror compensation without the complexity of real-time adaptive control. Current wavefront correctors, while dimensionally...
Institute of Scientific and Technical Information of China (English)
路小琪; 王峰; 刘毅; 王斌
2011-01-01
Basic principle of brushless doubly-fed machine were introduced, and its d-q mathematical model was studied. The dynamic simulation of brushless doubly-fed machine under open-loop was realized on Matlab/Simulink platform by use of constant V/F control strategy, while open-loop speed regulation experiment of brushless doubly-fed machine was completed on the experimental platform based on two-three-level inverter. Simulation and experimental results verified operation mechanism and good dynamic characteristics of brushless doubly-fed machine.%介绍了无刷双馈电动机的基本原理,研究了其转子速d-q参考轴下的数学模型；在Matlab/Simulink环境下,采用恒压频比控制策略完成了无刷双馈电动机开环状态下的动态特性仿真,并基于双三电平变频器建立了实验平台,完成了无刷双馈电动机的开环调速实验.仿真与实验结果验证了无刷双馈电动机的运行机理及其良好的动态特性.
New numerical methods for open-loop and feedback solutions to dynamic optimization problems
Ghosh, Pradipto
The topic of the first part of this research is trajectory optimization of dynamical systems via computational swarm intelligence. Particle swarm optimization is a nature-inspired heuristic search method that relies on a group of potential solutions to explore the fitness landscape. Conceptually, each particle in the swarm uses its own memory as well as the knowledge accumulated by the entire swarm to iteratively converge on an optimal or near-optimal solution. It is relatively straightforward to implement and unlike gradient-based solvers, does not require an initial guess or continuity in the problem definition. Although particle swarm optimization has been successfully employed in solving static optimization problems, its application in dynamic optimization, as posed in optimal control theory, is still relatively new. In the first half of this thesis particle swarm optimization is used to generate near-optimal solutions to several nontrivial trajectory optimization problems including thrust programming for minimum fuel, multi-burn spacecraft orbit transfer, and computing minimum-time rest-to-rest trajectories for a robotic manipulator. A distinct feature of the particle swarm optimization implementation in this work is the runtime selection of the optimal solution structure. Optimal trajectories are generated by solving instances of constrained nonlinear mixed-integer programming problems with the swarming technique. For each solved optimal programming problem, the particle swarm optimization result is compared with a nearly exact solution found via a direct method using nonlinear programming. Numerical experiments indicate that swarm search can locate solutions to very great accuracy. The second half of this research develops a new extremal-field approach for synthesizing nearly optimal feedback controllers for optimal control and two-player pursuit-evasion games described by general nonlinear differential equations. A notable revelation from this development
Open Loop and Closed Loop Performance of Switched Reluctance Motor with Various Converter Topologies
Directory of Open Access Journals (Sweden)
Malligunta Kiran Kumar
2014-07-01
Full Text Available Switched reluctance motor (SRM is becoming popular because of its simple construction, robustness and low-maintenance. This motor is very useful for high speed applications because no windings are placed on rotor and can also be used for variable speed applications in industries. Converter is one of the important elements in SRM which plays a very crucial role. In this paper various converter topologies for 6/4 switched reluctance motor and Asymmetric bridge converter topology for 8/6 switched reluctance motor are discussed. Finally a closed loop for each converter topology is proposed. The converter topologies are simulated by using MATLAB/SIMULINK. Constant speed is achieved in closed loop control.
PERFORMANCE OF A NEW DECODING METHOD USED IN OPEN-LOOP ALL-OPTICAL CHAOTIC COMMUNICATION SYSTEM
Institute of Scientific and Technical Information of China (English)
Liu Huijie; Feng Jiuchao
2011-01-01
A new decoding method with decoder is used in open-loop all-optical chaotic communication system under strong injection condition.The performance of the new decoding method is numerically investigated by comparing it with the common decoding method without decoder.For new decoding method,two cases are analyzed,including whether or not the output of the decoder is adjusted by its input to receiver.The results indicate the decoding quality can be improved by adjusting for the new decoding method.Meanwhile,the injection strength of decoder can be restricted in a certain range.The adjusted new decoding method with decoder can achieve better decoding quality than decoding method without decoder when the bit rate of message is under 5 Gb/s.However,a stronger injection for receiver is needed.Moreover,the new decoding method can broaden the range of injection strength acceptable for good decoding quality.Different message encryption techniques are tested,and the result is similar to that of the common decoding method,indicative of the fact that the message encoded by using Chaotic Modulation (CM) can be best recovered by the new decoding method owning to the essence of this encryption technique.
Indian Academy of Sciences (India)
Anirudh Guha; G Narayanan
2016-02-01
The objective of this paper is to study the influence of inverter dead-time on steady as well as dynamic operation of an open-loop induction motor drive fed from a voltage source inverter (VSI). Towards this goal, this paper presents a systematic derivation of a dynamic model for an inverter-fed induction motor, incorporating the effect of inverter dead-time, in the synchronously revolving dq reference frame. Simulation results based on this dynamic model bring out the impact of inverter dead-time on both the transient response and steady-state operation of the motor drive. For the purpose of steady-state analysis, the dynamic model of the motor drive is used to derive a steady-state model, which is found to be non-linear. The steady-state model shows that the impact of dead-time can be seen as an additional resistance in the stator circuit, whose value depends on the stator current. Towards precise evaluation of this dead-time equivalent resistance, an analytical expression is proposed for the same in terms of inverter dead-time, switching frequency, modulation index and load impedance. The notion of dead-time equivalent resistance is shown to simplify the solution of the non-linear steady-state model. The analytically evaluated steady-state solutions are validated through numerical simulations and experiments.
Zhu, Zhaoyi; Mu, Quanquan; Li, Dayu; Yang, Chengliang; Cao, Zhaoliang; Hu, Lifa; Xuan, Li
2016-10-17
The centroid-based Shack-Hartmann wavefront sensor (SHWFS) treats the sampled wavefronts in the sub-apertures as planes, and the slopes of the sub-wavefronts are used to reconstruct the whole pupil wavefront. The problem is that the centroid method may fail to sense the high-order modes for strong turbulences, decreasing the precision of the whole pupil wavefront reconstruction. To solve this problem, we propose a sub-wavefront estimation method for SHWFS based on the focal plane sensing technique, by which more Zernike modes than the two slopes can be sensed in each sub-aperture. In this paper, the effects on the sub-wavefront estimation method of the related parameters, such as the spot size, the phase offset with its set amplitude and the pixels number in each sub-aperture, are analyzed and these parameters are optimized to achieve high efficiency. After the optimization, open-loop measurement is realized. For the sub-wavefront sensing, we achieve a large linearity range of 3.0 rad RMS for Zernike modes Z2 and Z3, and 2.0 rad RMS for Zernike modes Z4 to Z6 when the pixel number does not exceed 8 × 8 in each sub-aperture. The whole pupil wavefront reconstruction with the modified SHWFS is realized to analyze the improvements brought by the optimized sub-wavefront estimation method. Sixty-five Zernike modes can be reconstructed with a modified SHWFS containing only 7 × 7 sub-apertures, which could reconstruct only 35 modes by the centroid method, and the mean RMS errors of the residual phases are less than 0.2 rad2, which is lower than the 0.35 rad2 by the centroid method.
Sahoo, Deepti; Andersson, Jonatan; Mattiasson, Bo
2009-06-01
Open-loop simulated moving bed (SMB) has been used for immobilized metal affinity chromatographic (IMAC) purification of his-tagged beta-glucosidase expressed in E. coli. A simplified approach based on an optimized single column protocol is used to design the open-loop SMB. A set of columns in the SMB represent one step in the chromatographic cycle i.e. there will be one set each of columns for load, wash, elution etc within the SMB. Only the wash and elution are operated with columns in sequence. The beta-glucosidase was purified to almost single band purity with a purification factor of 15 and a recovery of 91%. SMB-performance showed reduced buffer consumption, higher purification fold, a better yield and higher productivity.
Gottardi, Luciano; Gao, Jan-R; Hartog, Roland den; Hijmering, Richard; Hoevers, Henk; Khosropanah, Pourya; de Korte, Piet; van der Kuur, Jan; Lindeman, Mark; Ridder, Marcel
2016-01-01
SRON is developing the Frequency Domain Multiplexing (FDM) readout and the ultra low NEP TES bolometers array for the infrared spectrometer SAFARI on board of the Japanese space mission SPICA. The FDM prototype of the instrument requires critical and complex optimizations. For single pixel characterization under AC bias we are developing a simple FDM system working in the frequency range from 1 to 5 MHz, based on the open loop read-out of a linearized two-stage SQUID amplifier and high Q lithographic LC resonators. We describe the details of the experimental set-up required to achieve low power loading (< 1 fW) and low noise (NEP $\\sim 10^{-19} W/Hz^{1/2}$) in the TES bolometers. We conclude the paper by comparing the performance of a $4 \\cdot 10^{-19} W/Hz^{1/2}$ TES bolometer measured under DC and AC bias.
Farahania, N Darestani
2015-01-01
A formulation of a multi-input single-output closed-loop subspace system identification method is employed for the purpose of obtaining control-relevant model of the vacuum-plasma response in Damavand tokamak. Such a model is particularly well suited for robust controller design. The accuracy of the estimate of the plant dynamics is estimated by different experiments. The method described in this paper is a worst-case identification technique, in that it aims to minimize the error between the identified model and the true plant. The identified model fitness around defined operating point is more than 90% and with comparison by physical-based model it has better root mean square measure of the goodness of the fit.
Indian Academy of Sciences (India)
ANIRUDH GUHA; ABHISHEK CHETTY; C KUMARESAN; G NARAYANAN; R KRISHNAMOORTHY
2017-08-01
This paper presents the small-signal stability analysis of an 11-kW open-loop inverter-fed induction motor drive, including the effect of inverter dead-time. The analysis is carried out using an improved smallsignal model of the drive that has been reported in literature recently, and is used to demonstrate small-signal instability in a higher-power-level motor. Through small-signal stability analysis, the region of oscillatory behaviour is identified on the voltage versus frequency plane (V–f plane), considering no-load. These predictions using the improved model are also compared against predictions of a standard model of an inverter-fed inductionmotor including dead-time effect. The oscillatory behaviour of the 11-kW motor drive is also studied through extensive time-domain numerical simulations and actual measurements over wide ranges of operating conditions. Both the simulation and experimental results confirm the validity of the predictions by the improved analytical model. Further, these results establish that the analysis is valid for both sine-triangle pulse-width modulation (PWM) and conventional space vector PWM
Rahman, Md. Lutfor; Afrose, Tonima; Tahmina, Halima Khatun; Rinky, Rumana Parvin; Ali, Mohammad
2016-07-01
Pulsating heat pipe (PHP) is a new innovation in the modern era of miniaturizes thermal management system for its higher heating and cooling capacity. The objective of this experiment is to observe the performance of open loop pulsating heat pipe using two fluids at different filling ratios. This OLPHP is a copper capillary tube of 2.5mm outer diameter and 2mm inner diameter. It consists of 8 loops where the evaporative section is 50mm, adiabatic section is 120mm and condensation section is 80mm. The experiment is conducted with distilled water and acetone at 40%, 50%, 60%, and 70% filling ratios where 0° (vertical) is considered as definite angle of inclination. Distilled water and acetone are selected as working fluids considering their different latent heat of vaporization and surface tension. It is found that acetone shows lower thermal resistance than water at all heat inputs. Best performance of acetone is attained at 70% filling ratio. Water displays better heat transfer capability at 50% filling ratio.
绘制开环系统Nyquist曲线的研究%Research for Plotting Diagram of Open-loop Systems
Institute of Scientific and Technical Information of China (English)
王泽南
2001-01-01
从两个方面对如何更好地绘制开环系统曲线进行了研究： (1)对它的计算方式进行有效的改进，推出实、虚频特性计算通式，它方便于手算，更方便于计算机编程运算; (2)针对快速确定曲线有关形状给出了2个判据,即起始渐近线判据和实、虚频交点判据．%The method of effective plotting diagram of open-loop systems was studied in two aspects. Firstly, his calculus was efficaciously improved: the common formula of real and imaginary frequency response was advanced that is convenient for manual computation and more convenient for compute programming. Secondly, two criterions are posed for use of quick confirming the forms of diagram： they are the criterion of original asymptote and cross-point on real and imaginary axes.
Origin and control of instability in SCR/triac three-phase motor controllers
Dearth, J. J.
1982-01-01
The energy savings and reactive power reduction functions initiated by the power factor controller (PFC) are discussed. A three-phase PFC with soft start is examined analytically and experimentally to determine how well it controls the open loop instability and other possible modes of instability. The detailed mechanism of the open loop instability is determined and shown to impose design constraints on the closed loop system. The design is shown to meet those constraints.
Energy Technology Data Exchange (ETDEWEB)
Freedman, Vicky L.; Mackley, Rob D.; Waichler, Scott R.; Horner, Jacob A.
2013-09-26
In an open-loop groundwater heat pump (GHP) system, groundwater is extracted, run through a heat exchanger, and injected back into the ground, resulting in no mass balance changes to the flow system. Although the groundwater use is non-consumptive, the withdrawal and injection of groundwater may cause negative hydraulic and thermal impacts to the flow system. Because GHP is a relatively new technology and regulatory guidelines for determining environmental impacts for GHPs may not exist, consumptive use metrics may need to be used for permit applications. For consumptive use permits, a radius of influence is often used, which is defined as the radius beyond which hydraulic impacts to the system are considered negligible. In this paper, the hydraulic radius of influence concept was examined using analytical and numerical methods for a non-consumptive GHP system in southeastern Washington State. At this location, the primary hydraulic concerns were impacts to nearby contaminant plumes and a water supply well field. The results of this study showed that the analytical techniques with idealized radial flow were generally unsuited because they over predicted the influence of the well system. The numerical techniques yielded more reasonable results because they could account for aquifer heterogeneities and flow boundaries. In particular, the use of a capture zone analysis was identified as the best method for determining potential changes in current contaminant plume trajectories. The capture zone analysis is a more quantitative and reliable tool for determining the radius of influence with a greater accuracy and better insight for a non-consumptive GHP assessment.
组合式转子电机开环稳定性探讨%Research on Open-loop Stability of Combined Rotor Machine
Institute of Scientific and Technical Information of China (English)
陈学珍; 陈旭武; 刘俊
2014-01-01
The combined rotor machine is made up of a high density axially laminated magnetic reluctance seg-ment and a surface permanent magnet segment.Influences on the stability of the machine are analyzed for the different angle αbetween two-part d-axis,the conclusion has been drawn that the stable operation of the combined rotor motor can be obtained when the angle αmeets the certain conditions .And open-loop and no-load starting experiments on combined rotor motor are respectively completed when α=0,α=45°andα=90°,the experimental results show that theoretical analysis is correct ,which provides the reliable theoretical evidence for the combined rotor motor to realize the practical application .%组合式转子电机的转子由面贴式永磁段和高密度轴向叠片磁阻段组合而成。分析了2段 d轴之间的夹角α对电机稳定性的影响，得出了组合式转子电机稳定运行时α角应满足的条件，并分别对α＝0，α＝45°和α＝90°时3台组合式转子电机进行开环空载起动实验。实验结果表明该理论分析是正确的，为该组合式转子电机实用化提供了有力的理论依据。
Directory of Open Access Journals (Sweden)
F. Zus
2014-12-01
Full Text Available The Global Positioning System (GPS radio occultation (RO technique provides valuable input for numerical weather prediction and is considered as a data source for climate related research. Numerous studies outline the high precision and accuracy of RO atmospheric soundings in the upper troposphere and lower stratosphere. In this altitude region (8–25 km RO atmospheric soundings are considered to be free of any systematic error. In the tropical (30° S–30° N Lower (<8 km Troposphere (LT, this is not the case; systematic differences with respect to independent data sources exist and are still not completely understood. To date only little attention has been paid to the Open Loop (OL Doppler model. Here we report on a RO experiment carried out on-board of the twin satellite configuration TerraSAR-X and TanDEM-X which possibly explains to some extent biases in the tropical LT. In two sessions we altered the OL Doppler model aboard TanDEM-X by not more than ±5 Hz with respect to TerraSAR-X and compare collocated atmospheric refractivity profiles. We find a systematic difference in the retrieved refractivity. The bias mainly stems from the tropical LT; there the bias reaches up to ±1%. Hence, we conclude that the negative bias (several Hz of the OL Doppler model aboard TerraSAR-X introduces a negative bias (in addition to the negative bias which is primarily caused by critical refraction in our retrieved refractivity in the tropical LT.
Institute of Scientific and Technical Information of China (English)
刘栋; 汤广福; 郑健超; 贺之渊; 杨岳峰; 李强
2012-01-01
It is very hard to analyze the relationship between dynamic response and main circuit parameters of modular multi-level converter (MMC), because its AC and DC voltage is established by distributed sub-module capacitances. For providing basis for the design of the MMC controller, this paper presented the modeling method for MMC's state space equation and open-loop transfer function from state variables to control variables, and presented the controlled source decoupled model of average sub-module in the rotating coordinate system. Based on the systematic research and experience in developing the 49-level MMC-HVDC dynamic simulator, comparison result shows that the modeling process is valid and could be used in design of a closed-loop controller for actual MMC-HVDC project.%模块化多电平换流器(modular multi-level converter,MMC)由于其交直流电压由分散储能的子模块电容建立,因此分析其主电路参数与动态响应的关系非常困难.为给MMC-HVDC工程控制器的设计提供依据,分析此类系统一般运动模型和控制模型的建立过程,推导旋转坐标系下的子模块平均值受控源解耦模型和换流器状态空间方程;利用系统稳态工作点附近的小信号模型得到开环传递函数和动态响应表达式.最后针对中国电力科学研究院开发的MMC-HVDC动模仿真装置,利用经验公式和该文的方法分别计算开环响应时间常数,对比结果证明理论分析的正确性.
An optimal open/closed-loop control method with application to a pre-stressed thin duralumin plate
Nadimpalli, Sruthi Raju
The excessive vibrations of a pre-stressed duralumin plate, suppressed by a combination of open-loop and closed-loop controls, also known as open/closed-loop control, is studied in this thesis. The two primary steps involved in this process are: Step (I) with an assumption that the closed-loop control law is proportional, obtain the optimal open-loop control by direct minimization of the performance measure consisting of energy at terminal time and a penalty on open-loop control force via calculus of variations. If the performance measure also involves a penalty on closed-loop control effort then a Fourier based method is utilized. Step (II) the energy at terminal time is minimized numerically to obtain optimal values of feedback gains. The optimal closed-loop control gains obtained are used to describe the displacement and the velocity of open-loop, closed-loop and open/closed-loop controlled duralumin plate.
Modeling, Calibration and Control for Extreme-Precision MEMS Deformable Mirrors Project
National Aeronautics and Space Administration — Iris AO will develop electromechanical models and actuator calibration methods to enable open-loop control of MEMS deformable mirrors (DMs) with unprecedented...
MODEL PREDICTIVE CONTROL FUNDAMENTALS
African Journals Online (AJOL)
2012-07-02
Jul 2, 2012 ... paper, we will present an introduction to the theory and application of MPC with Matlab codes written to ... model predictive control, linear systems, discrete-time systems, ... and then compute very rapidly for this open-loop con-.
Institute of Scientific and Technical Information of China (English)
尹邦堂; 李相方; 隋秀香; 任美鹏
2011-01-01
The choke valve adjustment in field was mainly relied on technicians' field experience due to the limit of drilling technology and lack of advanced well control equipment. There is certain subjectivity and blindness and prone to large errors which result in formation leakage and overflow. All these may cause complexity of downhole pressure system, thereby adversely affecting the safety killing time, and may lead to accidents. The real-time pressure monitoring module is established using gas-liquid two-phase flow theory, and an open-loop well killing system was developed. The paper describes working principle of this system. The software design and implement of the following modules were introduced, including prevention fracturing formation, prevention casing shoe broken down, prevention choke valves and associated equipments damage, and prevention pumping equipment damage. The application of this system in CPOE3 drilling platform of Petrochina shows that it is safe and reliable. Its calculation and analysis are correct. The in time response, decisive command and accurate execution meet the expectation.%由于钻井总体技术水平的制约,及缺少先进的井控装置,油田现场主要依靠技术人员的经验判断进行节流调节.但是,这样的操作具有很大的差异性,且存在一定的主观性和盲目性,极易造成地层被压漏或发生溢流,导致井下压力系统复杂化,贻误安全压井时机,并可能酿成事故.基于气液两相流理论,建立了压力实时监测模板,并利用各项技术形成了计算机优化压井开环控制系统.阐述了该系统的工作原理,详细介绍了溢流压井中防地层破裂监测模板、防套管鞋处压裂监测模板、防节流相关装备损坏模板、防泵入相关装备损坏模板等的软件功能设计与实现.该系统在中国石油CPOE3平台进行了模拟开环控制试验,结果表明,该系统计算分析能力强、安全可靠,在压井过程中反应及时、
Nominal model predictive control
Grüne, Lars
2013-01-01
5 p., to appear in Encyclopedia of Systems and Control, Tariq Samad, John Baillieul (eds.); International audience; Model Predictive Control is a controller design method which synthesizes a sampled data feedback controller from the iterative solution of open loop optimal control problems.We describe the basic functionality of MPC controllers, their properties regarding feasibility, stability and performance and the assumptions needed in order to rigorously ensure these properties in a nomina...
Nominal Model Predictive Control
Grüne, Lars
2014-01-01
5 p., to appear in Encyclopedia of Systems and Control, Tariq Samad, John Baillieul (eds.); International audience; Model Predictive Control is a controller design method which synthesizes a sampled data feedback controller from the iterative solution of open loop optimal control problems.We describe the basic functionality of MPC controllers, their properties regarding feasibility, stability and performance and the assumptions needed in order to rigorously ensure these properties in a nomina...
Iterative LQG Controller Design Through Closed-Loop Identification
Hsiao, Min-Hung; Huang, Jen-Kuang; Cox, David E.
1996-01-01
This paper presents an iterative Linear Quadratic Gaussian (LQG) controller design approach for a linear stochastic system with an uncertain open-loop model and unknown noise statistics. This approach consists of closed-loop identification and controller redesign cycles. In each cycle, the closed-loop identification method is used to identify an open-loop model and a steady-state Kalman filter gain from closed-loop input/output test data obtained by using a feedback LQG controller designed from the previous cycle. Then the identified open-loop model is used to redesign the state feedback. The state feedback and the identified Kalman filter gain are used to form an updated LQC controller for the next cycle. This iterative process continues until the updated controller converges. The proposed controller design is demonstrated by numerical simulations and experiments on a highly unstable large-gap magnetic suspension system.
Institute of Scientific and Technical Information of China (English)
王敏娟; 陈建军; 魏永祥; 张超; 马洪波
2012-01-01
Structures with a piezoelectric intelligent beam were taken as study objects here. According to the method of interval analysis, the interval models of mass matrix and stiffness matrices with interval variables for structural physical parameters and geometric dimensions were built. From Rayleigh quotient for dynamic characteristic of structural vibration, and based on the interval algorithms, the computation expressions of natural frequencies of a structural open-loop system were deduced. Through an example, the effects of the uncertainty of the structural interval parameters on the structural natural frequency were inspected, and the model constructed and the method proposed here were verified. It was shown that the interval coefficient method is applicable in dealing with the dynamic characteristic of an open-loop system of an intelligent beam.%以区间参数压电智能梁结构为研究对象,在材料性能参数和几何尺寸为区间变量时采用区间分析法建立了结构质量矩阵和刚度矩阵的区间模型.从求解结构振动动态特性的Rayleigh商出发,利用区间变量运算法则推导出了结构开环系统固有频率的数字特征表达式.通过算例,考察了区间参数对结构固有频率特性的影响,验证了所建模型和方法的可行性与合理性.研究结果表明,文中利用区间系数分析法来研究压电智能梁结构开环系统的动力特性具有一定的工程应用价值.
Institute of Scientific and Technical Information of China (English)
曹利波
2013-01-01
According to the importance of the CO2 open loop cycle refrigeration applied to the rescue cabin, the refuge chamber and other limited airtight space, the FLOWMASTER simulation software of the thermal fluid system was applied to design the simulation system of the CO2 open loop cycle refrigeration applied to a limited airtight space. Under the conditions to meet the designed refrigeration value and the pressure drop and temperature drop at the inlet and outlet of the pneumatic blower, the tube length of the evaporator was optimized and the optimum length of the evaporator was obtained. Meanwhile the refrigeration system features and the different refrigeration value under the non designed performances were checked.The test certification was conducted on the refrigeration simulation system.The simulated value and the test value were well fitted and the simulation accuracy and precision of the system were verified.%针对CO2开放式制冷在避难硐室、救生舱等有限密闭空间中应用的重要性,利用FLOWMASTER热流体计算仿真软件,设计了一种用于有限密闭空间的CO2开放式制冷仿真系统,在满足设计制冷量和气动风机进出口压降、温降的条件下,对蒸发器管长进行优化,获得了最佳蒸发器长度,同时对非设计工况下的制冷系统特性及不同制冷量进行校核,并对该制冷仿真系统进行了试验验证,仿真值与试验值吻合良好,验证了系统仿真的准确性和精确性.
Control analysis and experimental verification of a practical dc–dc boost converter
Directory of Open Access Journals (Sweden)
Saswati Swapna Dash
2015-12-01
Full Text Available This paper presents detailed open loop and closed loop analysis on boost dc–dc converter for both voltage mode control and current mode control. Here the boost dc–dc converter is a practical converter considering all possible parasitic elements like ESR and on state voltage drops. The open loop control, closed loop current mode control and voltage mode control are verified. The comparative study of all control techniques is presented. The PI compensator for closed loop current mode control is designed using these classical techniques like root locus technique and bode diagram. The simulation results are validated with the experimental results of voltage mode control for both open loop and closed loop control.
USING OPTIMAL FEEDBACK CONTROL FOR CHAOS TARGETING
Institute of Scientific and Technical Information of China (English)
PENG ZHAO-WANG; ZHONG TING-XIU
2000-01-01
Since the conventional open-loop optimal targeting of chaos is very sensitive to noise, a close-loop optimal targeting method is proposed to improve the targeting performance under noise. The present optimal targeting model takes into consideration both precision and speed of the targeting procedure. The parameters, rather than the output, of the targeting controller, are directly optimized to obtain optimal chaos targeting. Analysis regarding the mechanism is given from physics aspect and numerical experiment on the Hénon map is carried out to compare the targeting performance under noise between the close-loop and the open-loop methods.
Semiglobal H-infty state feedback control
DEFF Research Database (Denmark)
Cromme, Marc
1997-01-01
semi-global set-stabilizing H-infty control is local H-infty control within some given compact set O such that all state trajectories are bounded inside O, and are approaching an open loop invariant set S subset O as t -> infinity. Sufficient conditions for the existance of a continuous statefeed...
Hybrid force-velocity sliding mode control of a prosthetic hand.
Engeberg, Erik D; Meek, Sanford G; Minor, Mark A
2008-05-01
Four different methods of hand prosthesis control are developed and examined experimentally. Open-loop control is shown to offer the least sensitivity when manipulating objects. Force feedback substantially improves upon open-loop control. However, it is shown that the inclusion of velocity and/or position feedback in a hybrid force-velocity control scheme can further improve the functionality of hand prostheses. Experimental results indicate that the sliding mode controller with force, position, and velocity feedback is less prone to unwanted force overshoot when initially grasping objects than the other controllers.
Clementina Caputo, Maria; Masciale, Rita; Masciopinto, Costantino; De Carlo, Lorenzo
2016-04-01
The high cost and scarcity of fossil fuels have promoted the increased use of natural heat for a number of direct applications. Just as for fossil fuels, the exploitation of geothermal energy should consider its environmental impact and sustainability. Particular attention deserves the so-called open loop geothermal groundwater heat pump (GWHP) system, which uses groundwater as geothermal fluid. From an economic point of view, the implementation of this kind of geothermal system is particularly attractive in coastal areas, which have generally shallow aquifers. Anyway the potential problem of seawater intrusion has led to laws that restrict the use of groundwater. The scarcity of freshwater could be a major impediment for the utilization of geothermal resources. In this study a new methodology has been proposed. It was based on an experimental approach to characterize a coastal area in order to exploit the low-enthalpy geothermal resource. The coastal karst and fractured aquifer near Bari, in Southern Italy, was selected for this purpose. For the purpose of investigating the influence of an open-loop GWHP system on the seawater intrusion, a long-term pumping test was performed. The test simulated the effects of a prolonged withdrawal on the chemical-physical groundwater characteristics of the studied aquifer portion. The duration of the test was programmed in 16 days, and it was performed with a constant pumping flowrate of 50 m3/h. The extracted water was outflowed into an adjacent artificial channel, by means of a piping system. Water depth, temperature and electrical conductivity of the pumped water were monitored for 37 days, including also some days before and after the pumping duration. The monitored parameters, collected in the pumping and in five observation wells placed 160 m down-gradient with respect to the groundwater flow direction, have been used to estimate different scenarios of the impact of the GWHP system on the seawater intrusion by mean of a
Bundick, W. Thomas; Middleton, David B.; Poole, William L.
1990-01-01
An experimental magnetic leader cable (MLC) system designed to measure aircraft lateral displacement from centerline and heading relative to centerline during rollout, turnoff, and taxi was tested at NASA's Wallops Flight Facility using NASA's Transport System Research Vehicle (TSRV), a modified B-737. The MLC system consisted of ground equipment that produced a magnetic field about a wire along runway centerline and airborne equipment that detected the strength and direction of this field and computed displacement and heading. Results of these tests indicate that estimates of aircraft displacement from centerline produced by the magnetic leader cable system using either of the two algorithms appear to be adequate for use by an automatic control system during rollout, turnoff, and taxi. Estimates of heading, however, are not sufficiently accurate for use, probably because of distortion of the magnetic field by the metal aircraft.
Physical damping in IDA-PBC controlled underactuated mechanical systems
Gomez-Estern, F.; Schaft, van der A.J.
2004-01-01
Energy shaping and passivity-based control designs have proven to be effective in solving control problems for tinderactttated mechanical systems. In recent works, interconnection and damping assignment passivity-based control (IDA-PEC) has been successfully applied to open-loop conservative models,
Optimal Excitation Controller Design for Wind Turbine Generator
Directory of Open Access Journals (Sweden)
A. K. Boglou
2011-01-01
Full Text Available An optimal excitation controller design based on multirate-output controllers (MROCs having a multirate sampling mechanismwith different sampling period in each measured output of the system is presented. The proposed H∞ -control techniqueis applied to the discrete linear open-loop system model which represents a wind turbine generator supplying an infinite busthrough a transmission line.
Implementation of Dynamic Simulating Source Design by Using Open Loop Mode%采用开环模式实现深空动态模拟源设计
Institute of Scientific and Technical Information of China (English)
邓永铭
2009-01-01
由于深空探测的作用距离十分遥远,最大测控距离能达到几百万公里,信号的传播时延大,因而给深空动态模拟源的设计带来了一些技术难点.针对这些难点,在结合运动方程的基础上提出了采用开环模式实现动态模拟源的设计方案.通过分析可知,该方案具有电路简单、节约成本的特点,易于在工程中实现.%Because of the extreme operating distance of deep space exploration which can even reach several million kilometers, and the large signal propaganda delay, it brings some technical difficulties for deep space dynamic simulating source design. To solve these technical difficulties, this paper presents a dynamic simulat source design scheme by using the open loop mode on the basis of the movement equation. Analysis shows that this scheme is featured by simple circuit and low cost, and can be easily fulfilled in projects.
Gómez-Estern, F.; Schaft, A.J. van der
2004-01-01
Energy shaping and passivity-based control designs have proven to be effective in solving control problems for underactuated mechanical systems. In recent works, Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) has been successfully applied to open loop conservative models, i
Saha, Suman; Das, Shantanu; Gupta, Amitava
2012-01-01
A novel conformal mapping based Fractional Order (FO) methodology is developed in this paper for tuning existing classical (Integer Order) Proportional Integral Derivative (PID) controllers especially for sluggish and oscillatory second order systems. The conventional pole placement tuning via Linear Quadratic Regulator (LQR) method is extended for open loop oscillatory systems as well. The locations of the open loop zeros of a fractional order PID (FOPID or PI{\\lambda}D{\\mu}) controller have been approximated in this paper vis-\\`a-vis a LQR tuned conventional integer order PID controller, to achieve equivalent integer order PID control system. This approach eases the implementation of analog/digital realization of a FOPID controller with its integer order counterpart along with the advantages of fractional order controller preserved. It is shown here in the paper that decrease in the integro-differential operators of the FOPID/PI{\\lambda}D{\\mu} controller pushes the open loop zeros of the equivalent PID cont...
Institute of Scientific and Technical Information of China (English)
倪晓理; 黄晓津; 张亚军
2013-01-01
A low temperature nuclear heating reactor (NHR) power plant is needed to provide all the resources including desalted water ,heat and industrial steam ,and part of electricity if a city near the sea is far away from fresh water supply network ,power grid and heating network .The goal is to obtain the best economic benefits and to achieve the optimal economic operation under the precondition of ensuring the safety of low temper-ature nuclear heating reactor .In this paper ,an open-loop optimization method was used to study the steady-state operation target of NHR under the load following operation mode ,and to provide input parameters for the design analysis of NHR load following control system .%为满足海边的工业开发小区在远离淡水网、热网时，由一座低温核供热堆动力厂提供小区全部淡化海水、供热、工业蒸汽和部分用电的需要，目标是在保证安全性的前提下，使低温核供热堆取得最佳的经济效益，达到运行经济性最优。本文采用开环优化的方法，研究低温核供热堆在负荷跟踪运行方式下的稳态运行目标，并为低温核供热堆负荷跟踪控制系统的分析设计提供负荷需求的输入参数。
Triangulations, Subdivisions, and Covers for Control of Affine Hypersurface Systems on Polytopes
Lin, Zhiyun
2009-01-01
This paper studies the problem for an affine hypersurface system to reach a polytopic target set starting from inside a polytope in the state space. We present an exhaustive solution which begins with a characterization of states which can reach the target by open-loop control and concludes with a systematic procedure to synthesize a feedback control. Our emphasis is on methods of subdivision, triangulation, and covers which explicitly account for the capabilities of the control system. In contrast with previous literature, the partition methods are guaranteed to yield a correct feedback synthesis, assuming the problem is solvable by open-loop control.
VT Geothermal Open Loop Systems - well points
Vermont Center for Geographic Information — (Link to Metadata) The Renewable Energy Atlas of Vermont and this dataset were created to assist town energy committees, the Clean Energy Development Fund and other...
INTEGRATED ROBOT-HUMAN CONTROL IN MINING OPERATIONS
Energy Technology Data Exchange (ETDEWEB)
George Danko
2006-04-01
This report describes the results of the 2nd year of a research project on the implementation of a novel human-robot control system for hydraulic machinery. Sensor and valve re-calibration experiments were conducted to improve open loop machine control. A Cartesian control example was tested both in simulation and on the machine; the results are discussed in detail. The machine tests included open-loop as well as closed-loop motion control. Both methods worked reasonably well, due to the high-quality electro-hydraulic valves used on the experimental machine. Experiments on 3-D analysis of the bucket trajectory using marker tracking software are also presented with the results obtained. Open-loop control is robustly stable and free of short-term dynamic problems, but it allows for drifting away from the desired motion kinematics of the machine. A novel, closed-loop control adjustment provides a remedy, while retaining much of the advantages of the open-loop control based on kinematics transformation. Additional analysis of previously recorded, three-dimensional working trajectories of the bucket of large mine shovels was completed. The motion patterns, when transformed into a family of curves, serve as the basis for software-controlled machine kinematics transformation in the new human-robot control system.
Further results on switched control of linear systems with constraints
Persis, Claudio De; Santis, Raffaella De; Morse, A. Stephen
2002-01-01
In a previous paper we proposed a supervisory control system to globally regulate to zero the state of a very poorly modeled, open-loop unstable but not exponentially unstable, linear process in the presence of input constraints. The process to control was unknown but assumed to belong to a finite f
Hydraulic drive and control system of the cone collecting robot
Institute of Scientific and Technical Information of China (English)
Kong Qinghua; Liu Jinhao; Lu Huaimin
1999-01-01
This paper describes the basic structure and design and operation principle of the hydraulic drive and control system with two pumps and two circuits. The manipulator of the cone collecting robot designed is full driven by hydraulic, which has five freedoms. The computer and electrohydraulic proportion velocity regulating valve were installed to realize open loop serve control for reducing cost and easy application.
Design of switched controllers for discrete singular bilinear systems
Institute of Scientific and Technical Information of China (English)
Xiuhua ZHANG; Qingling ZHANG
2007-01-01
In this paper, switched controllers are designed for a class of nonlinear discrete singular systems and a class of discrete singular bilinear systems. An invariant principle is presented for such switched nonlinear singular systems.The invariant principle and the switched controllers are used to globally stabilize a class of singular bilinear systems that are not open-loop stable.
Institute of Scientific and Technical Information of China (English)
杨剑; 王智化; 张彦威; 陈云; 周俊虎; 岑可法
2011-01-01
In order to optimize the process and thermal efficiency of the open-loop sulfur-iodine (SI) thermo-chemical cycle for production of hydrogen, a flowsheet of open-loop SI thermo-chemical cycle was designed and simulated by Aspen Plus. The heat and mass balance as well as thermal efficiency were first calculated. The maximum thermal efficiency of the process was 66.2％ considering waste heat recoveryand pumping power. Secondly, through sensitivity analysis, the effects of 5 operating parameters like: reflux ratio at HI distillation column, pressure in HI distillation column, flow rate of HI phase, conversion ratio of HI and mass fraction of H2 SO4 were evaluated to the thermal efficiency. Results show that the flow rate of HI phase and reflux ratio of the HI distillation column are the primary paramenters influence the total efficiency, while the other parameters are not so obviously. Through optimization of the Bunsen reactor operation condition, the flow rate of the HI phase can be reduced therefore improve the whole thermal efficiency. The simulation results agree well with published datas and can be used as reference for design and optimization of the large scale SI thermo-chemical cycle H2 production system.%为了对热化学硫碘开路循环制氢系统进行优化设计及热效率评估,利用大型化工流程模拟软件AspenPlus对硫碘开路循环联产氢气和硫酸系统进行设计和模拟,计算质量、能量平衡及热效率.在考虑泵功和废热回收的情况下,开路系统的最高计算热效率达到66.2%.其次,利用灵敏度分析,分别考察HI精馏塔同流比、精馏塔压力、HI相循环量、HI分解率和产品硫酸质量分数5个设计参数对系统效率的影响.结果显示,HI相循环量和精馏塔同流比是影响系统效率的主要因素,其他参数对效率影响较小.通过优化本生反应操作条件可显著减少HI相的循环量,提高系统效率.计算结果与文献参考值接近,为今后大
Directory of Open Access Journals (Sweden)
Limei Zhao
2005-02-01
Full Text Available This paper presents the design and implementation of a DSP-based controller for a super high-speed (>80,000 rpm permanent magnet synchronous motor (PMSM. The PMSM is a key component of the centrifugal compressor drive of a reverse Brayton cryocooler that is currently under development for NASA and Florida Solar Energy Center. The design of the PMSM open-loop control is presented. Experimental results with open-loop control schemes are presented. System optimization and analysis are also illustrated. They verify the effectiveness of the controller design and the optimization scheme.
Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control
2015-01-01
In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with co...
Properties of Closed-Loop Reference Models in Adaptive Control: Part I Full States Accessible
Gibson, Travis E; Lavretsky, Eugene
2012-01-01
This paper explores the properties of adaptive systems with closed-loop reference models. Historically, reference models in adaptive systems run open-loop in parallel with the plant and controller, using no information from the plant or controller to alter the trajectory of the reference system. Closed-loop reference models on the other hand use information from the plant to alter the reference trajectory. We show that closed-loop reference models have one more free design parameter as compared to their open-loop counterparts. Using the extra design freedom, we study closed--loop reference models and their impact on transient response and robustness in adaptive systems.
Active Control of Open Cavities
UKeiley, Lawrence
2010-01-01
Open loop edge blowing was demonstrated as an effective method for reducing the broad band and tonal components of the fluctuating surface pressure in open cavities. Closed loop has been successfully applied to low Mach number open cavities. Need to push actuators that are viable for closed loop control in bandwidth and output. Need a better understanding of the effects of control on the flow through detailed measurements so better actuation strategies can be developed.
Institute of Scientific and Technical Information of China (English)
朱西产; 刘智超; 李霖
2015-01-01
In order to describe drivers’ behavior when driver takes an emergency lane-change action, an open-loop model was proposed based on the naturalistic driving data which was colected by the program named China pilot Field Operation Test. Almost 228 lane-change use cases were extracted from the naturalistic driving data. Steering wheel angle rate combined with steering wheel angle were used as iflters to classify the different emergency degrees of lane-change. The duration of drivers’ emergency lane-change was studied based on a liner dependency between the maximum values of both steering wheel angle and steering wheel angle rate. Parameters were iftted by the 50th percentile of the naturalistic driving data colected from lane-change scenarios .The model can be applied in research of Chinese drivers’ behavior and its values have been proved by both signiifcant test and correlation test. The results of tests show that coherence of the outputs from real driver and the model is good, so the model can wel describe Chinese drivers’ emergency lane-change behavior.%基于“中国大型实车路试先行实验(China Pilot-FOT)”所采集的自然驾驶数据，提出了一种开环模型，它可以描述驾驶员紧急变换车道行为。将方向盘转角和方向盘转角变化率作为变道紧急程度的筛选条件，从中筛选出228例紧急变换车道工况。基于最大方向盘转角与最大方向盘转角变化率的线性关系，分析了紧急变换车道的持续时间。利用其中50百分位驾驶数据，来拟合模型参数。使用相关性和显著性检验，验证了真实驾驶数据与驾驶计算模型的关系。结果表明：该模型的输出结果与真实驾驶员操作结果一致性良好。因此，该模型可以描述中国一般驾驶员紧急变道行为。
An optimal control framework for estimating autopilot safety margins
Govindarjan, N.; De Visser, C.C.; Van Kampen, E.; Krishnakumar, K.; Barlow, J.; Stepanyan, V.
2014-01-01
This paper presents an optimal control framework to determine a collection of open-loop command signals that mathematically guarantees operation of an aircraft within certain prescribed state constraints. The framework is specifically applied to estimate margins for the reference command inputs of
An optimal control framework for estimating autopilot safety margins
Govindarjan, N.; De Visser, C.C.; Van Kampen, E.; Krishnakumar, K.; Barlow, J.; Stepanyan, V.
2014-01-01
This paper presents an optimal control framework to determine a collection of open-loop command signals that mathematically guarantees operation of an aircraft within certain prescribed state constraints. The framework is specifically applied to estimate margins for the reference command inputs of a
Robust time-optimal control of uncertain structural dynamic systems
Wie, Bong; Sinha, Ravi; Liu, Qiang
1993-01-01
A time-optimal open-loop control problem of flexible spacecraft in the presence of modeling uncertainty has been investigated. The results indicate that the proposed approach significantly reduces the residual structural vibrations caused by modeling uncertainty. The results also indicate the importance of proper jet placement for practical tradeoffs among the maneuvering time, fuel consumption, and performance robustness.
PID Controller Settings Based on a Transient Response Experiment
Silva, Carlos M.; Lito, Patricia F.; Neves, Patricia S.; Da Silva, Francisco A.
2008-01-01
An experimental work on controller tuning for chemical engineering undergraduate students is proposed using a small heat exchange unit. Based upon process reaction curves in open-loop configuration, system gain and time constant are determined for first order model with time delay with excellent accuracy. Afterwards students calculate PID…
THE PRINCIPLE OF ROBUSTNESS IN GENERALIZED PREDICTIVE CONTROL
Institute of Scientific and Technical Information of China (English)
SunMingwei; ChenZengqiang; YuanZhuzhi
1999-01-01
This paper deeply analyzes the closed-loop nature of GPC in the framework of internal model control (IMC) theory. A new sort of relation lies in the feedback structure so thatrobust reason can be satisfactorily explained. The result is significant because the previous conclusions are only applied to open-loop stable plant (or model).
An optimal control framework for estimating autopilot safety margins
Govindarjan, N.; De Visser, C.C.; Van Kampen, E.; Krishnakumar, K.; Barlow, J.; Stepanyan, V.
2014-01-01
This paper presents an optimal control framework to determine a collection of open-loop command signals that mathematically guarantees operation of an aircraft within certain prescribed state constraints. The framework is specifically applied to estimate margins for the reference command inputs of a
Modeling and control of isolated full bridge boost DC-DC converter implemented in FPGA
DEFF Research Database (Denmark)
Taeed, Fazel; Nymand, M.
2013-01-01
design are discussed. In the next step a digital PI controller is designed and implemented in a FPGA to control the output voltage. Using the injection transformer method the open loop transfer function in closed loop is measured and modeling results are verified by experimental results. © 2013 IEEE....
Space Shuttle flight control system
Klinar, W. J.; Kubiak, E. T.; Peters, W. H.; Saldana, R. L.; Smith, E. E., Jr.; Stegall, H. W.
1975-01-01
The Space Shuttle is a control stabilized vehicle with control provided by an all digital, fly-by-wire flight control system. This paper gives a description of the several modes of flight control which correspond to the Shuttle mission phases. These modes are ascent flight control (including open loop first stage steering, the use of four computers operating in parallel and inertial guidance sensors), on-orbit flight control (with a discussion of reaction control, phase plane switching logic, jet selection logic, state estimator logic and OMS thrust vector control), entry flight control and TAEM (terminal area energy management to landing). Also discussed are redundancy management and backup flight control.
Randomized control of open quantum systems
Viola, L
2006-01-01
The problem of open-loop dynamical control of generic open quantum systems is addressed. In particular, I focus on the task of effectively switching off environmental couplings responsible for unwanted decoherence and dissipation effects. After revisiting the standard framework for dynamical decoupling via deterministic controls, I describe a different approach whereby the controller intentionally acquires a random component. An explicit error bound on worst-case performance of stochastic decoupling is presented.
Closed-loop control of an experimental mixing layer using machine learning control
Parezanović, Vladimir; Cordier, Laurent; Noack, Bernd R; Delville, Joël; Bonnet, Jean-Paul; Segond, Marc; Abel, Markus; Brunton, Steven L
2014-01-01
A novel framework for closed-loop control of turbulent flows is tested in an experimental mixing layer flow. This framework, called Machine Learning Control (MLC), provides a model-free method of searching for the best function, to be used as a control law in closed-loop flow control. MLC is based on genetic programming, a function optimization method of machine learning. In this article, MLC is benchmarked against classical open-loop actuation of the mixing layer. Results show that this method is capable of producing sensor-based control laws which can rival or surpass the best open-loop forcing, and be robust to changing flow conditions. Additionally, MLC can detect non-linear mechanisms present in the controlled plant, and exploit them to find a better type of actuation than the best periodic forcing.
Precision Tension Control System Using Magnetic Particle Clutch
Institute of Scientific and Technical Information of China (English)
王春香; 杨汝清; 王永章; 路华
2004-01-01
The control of the stability of the filament tension is one of the crucial techniques ensuring the component quality of the composite materials. The open-loop tension control system, with industrial control computer as the core,magnetic particle clutch as the actuator, equipped with compensation technique is researched and manufactured.It can assure the tension control stability of the yarn in filament winding process and increase the control precision of the whole system.
Directory of Open Access Journals (Sweden)
Nataša D. Kljajić
2016-07-01
Full Text Available An important phase in missile systems development is flight testing and simulation in the environmental conditions dictated by the operation the system is made for. Since field testing of complex systems means a big financial burden and a time consuming process, hardware in the loop (HIL simulations represent a very effective solution for saving both costs and time. This paper presents an implementation of a control application that integrates synchronized data generation and acquisition on the five-axis missile and target flight motion simulator owned by the HIL laboratory. The described simulation application is a result of a missile development engineer's need for a simple way to acquire information on a real missile response, when desired control signals are provided. The solution is realized in Lab VIEW software using a robust software design architecture named 'classic state machine'. / Важнейшим фактором в развитии ракетных систем является этап моделирования и симуляции движения ракеты в соответствующих операционным параметрам условиях. Учитывая высокую стоимость полевых испытаний подобных систем, большие финансовые расходы и продолжительность подготовительных мероприятий, симулирование в рамках программно-аппаратного моделирования (Hardware in the loop - HIL является наиболее эффективным испытательным решением. В данной статье описан процесс внедрения системы управления, то есть, синхронизированного генерирования и активации данных пятиосевого имитатора
Parametric Approach to Trajectory Tracking Control of Robot Manipulators
Directory of Open Access Journals (Sweden)
Shijie Zhang
2013-01-01
Full Text Available The mathematic description of the trajectory of robot manipulators with the optimal trajectory tracking problem is formulated as an optimal control problem, and a parametric approach is proposed for the optimal trajectory tracking control problem. The optimal control problem is first solved as an open loop optimal control problem by using a time scaling transform and the control parameterization method. Then, by virtue of the relationship between the optimal open loop control and the optimal closed loop control along the optimal trajectory, a practical method is presented to calculate an approximate optimal feedback gain matrix, without having to solve an optimal control problem involving the complex Riccati-like matrix differential equation coupled with the original system dynamics. Simulation results of 2-link robot manipulator are presented to show the effectiveness of the proposed method.
Robust Adaptive Speed Control of Induction Motor Drives
DEFF Research Database (Denmark)
Bidstrup, N.
This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... dependent of the operating point, which is characterised by the speed and load. If the requirements to the controller performance is large, then it is difficult to maintain specified controller performance with a fixed controller, because of the open loop variations. An auto-tuner based on least squares......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...
Robust Adaptive Speed Control of Induction Motor Drives
DEFF Research Database (Denmark)
Bidstrup, N.
This thesis concerns speed control of current vector controlled induction motor drives (CVC drives). The CVC drive is an existing prototype drive developed by Danfoss A/S, Transmission Division. Practical tests have revealed that the open loop dynamical properties of the CVC drive are highly...... dependent of the operating point, which is characterised by the speed and load. If the requirements to the controller performance is large, then it is difficult to maintain specified controller performance with a fixed controller, because of the open loop variations. An auto-tuner based on least squares......, (LS) identification and generalized predictive control (GPC) has been implemented and tested on the CVC drive. Allthough GPC is a robust control method, it was not possible to maintain specified controller performance in the entire operating range. This was the main reason for investigating truly...
Low-level finite state control of knee joint in paraplegic standing
Mulder, A.J.; Veltink, P.H.; Boom, H.B.K.; Zilvold, G.
1992-01-01
Low-level finite state (locked-unlocked) control is compared with open-loop stimulation of the knee extensor muscles in functional electrical stimulation (FES) induced paraplegic standing. The parameters were: duration of standing, relative torque loss in knee extensor muscles, knee angle stability,
Institute of Scientific and Technical Information of China (English)
方孝杰; 南余荣
2011-01-01
文中主要研究的对象是开环控制的交错并联BOOST PFC,且工作于临界续断模式,它的从变换器与主变换器在开通时同步,且主从变换器都工作在电流模式.文章指出只有这种主从方式能提供一个稳定的开环工作点.仿真实验设计了一台输入功率为400 W,宽范围输入电压,400 V输出电压的实验样机,实验结果验证了理论分析的正确性.
Chaos control via a simple fractional-order controller
Energy Technology Data Exchange (ETDEWEB)
Tavazoei, Mohammad Saleh [Advanced Control System Lab., Electrical Engineering Department, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Haeri, Mohammad [Advanced Control System Lab., Electrical Engineering Department, Sharif University of Technology, Tehran (Iran, Islamic Republic of)], E-mail: haeri@sina.sharif.edu
2008-02-04
In this Letter, we propose a fractional-order controller to stabilize the unstable fixed points of an unstable open-loop system. Also, we show that this controller has strong ability to eliminate chaotic oscillations or reduce them to regular oscillations in the chaotic systems. This controller has simple structure and is designed very easily. To determine the control parameters, one needs only a little knowledge about the plant and therefore, the proposed controller is a suitable choice in the control of uncertain chaotic systems.
Dynamics and control of Lorentz-augmented spacecraft relative motion
Yan, Ye; Yang, Yueneng
2017-01-01
This book develops a dynamical model of the orbital motion of Lorentz spacecraft in both unperturbed and J2-perturbed environments. It explicitly discusses three kinds of typical space missions involving relative orbital control: spacecraft hovering, rendezvous, and formation flying. Subsequently, it puts forward designs for both open-loop and closed-loop control schemes propelled or augmented by the geomagnetic Lorentz force. These control schemes are entirely novel and represent a significantly departure from previous approaches.
Improvements and applications of entrainment control for nonlinear dynamical systems.
Liu, Fang; Song, Qiang; Cao, Jinde
2008-12-01
This paper improves the existing entrainment control approaches and develops unified schemes to chaos control and generalized (lag, anticipated, and complete) synchronization of nonlinear dynamical systems. By introducing impulsive effects to the open-loop control method, we completely remove its restrictions on goal dynamics and initial conditions, and derive a sufficient condition to estimate the upper bound of impulsive intervals to ensure the global asymptotic stability. We then propose two effective ways to implement the entrainment strategy which combine open-loop and closed-loop control, and we prove that the feedback gains can be chosen according to a lower bound or be tuned with an adaptive control law. Numerical examples are given to verify the theoretical results and to illustrate their applications.
Feedback Scheduling of Priority-Driven Control Networks
Xia, Feng; Tian, Yu-Chu
2008-01-01
With traditional open-loop scheduling of network resources, the quality-of-control (QoC) of networked control systems (NCSs) may degrade significantly in the presence of limited bandwidth and variable workload. The goal of this work is to maximize the overall QoC of NCSs through dynamically allocating available network bandwidth. Based on codesign of control and scheduling, an integrated feedback scheduler is developed to enable flexible QoC management in dynamic environments. It encompasses a cascaded feedback scheduling module for sampling period adjustment and a direct feedback scheduling module for priority modification. The inherent characteristics of priority-driven control networks make it feasible to implement the proposed feedback scheduler in real-world systems. Extensive simulations show that the proposed approach leads to significant QoC improvement over the traditional open-loop scheduling scheme under both underloaded and overloaded network conditions.
Stochastic optimal control of single neuron spike trains
DEFF Research Database (Denmark)
Iolov, Alexandre; Ditlevsen, Susanne; Longtin, Andrë
2014-01-01
Objective. External control of spike times in single neurons can reveal important information about a neuron's sub-threshold dynamics that lead to spiking, and has the potential to improve brain–machine interfaces and neural prostheses. The goal of this paper is the design of optimal electrical...... stimulation of a neuron to achieve a target spike train under the physiological constraint to not damage tissue. Approach. We pose a stochastic optimal control problem to precisely specify the spike times in a leaky integrate-and-fire (LIF) model of a neuron with noise assumed to be of intrinsic or synaptic...... to the spike times (open-loop control). Main results. We have developed a stochastic optimal control algorithm to obtain precise spike times. It is applicable in both the supra-threshold and sub-threshold regimes, under open-loop and closed-loop conditions and with an arbitrary noise intensity; the accuracy...
Robustified time-optimal control of uncertain structural dynamic systems
Liu, Qiang; Wie, Bong
1991-01-01
A new approach for computing open-loop time-optimal control inputs for uncertain linear dynamical systems is developed. In particular, the single-axis, rest-to-rest maneuvering problem of flexible spacecraft in the presence of uncertainty in model parameters is considered. Robustified time-optimal control inputs are obtained by solving a parameter optimization problem subject to robustness constraints. A simple dynamical system with a rigid-body mode and one flexible mode is used to illustrate the concept.
Nonlinear Model Predictive Control for Oil Reservoirs Management
DEFF Research Database (Denmark)
Capolei, Andrea
. With this objective function we link the optimization problem in production optimization to the Markowitz portfolio optimization problem in finance or to the the robust design problem in topology optimization. In this study we focus on open-loop configuration, i.e. without measurement feedback. We demonstrate......, the research community is working on improving current feedback model-based optimal control technologies. The topic of this thesis is production optimization for water flooding in the secondary phase of oil recovery. We developed numerical methods for nonlinear model predictive control (NMPC) of an oil field....... Further, we studied the use of robust control strategies in both open-loop, i.e. without measurement feedback, and closed-loop, i.e. with measurement feedback, configurations. This thesis has three main original contributions: The first contribution in this thesis is to improve the computationally...
Attitude-Control Algorithm for Minimizing Maneuver Execution Errors
Acikmese, Behcet
2008-01-01
A G-RAC attitude-control algorithm is used to minimize maneuver execution error in a spacecraft with a flexible appendage when said spacecraft must induce translational momentum by firing (in open loop) large thrusters along a desired direction for a given period of time. The controller is dynamic with two integrators and requires measurement of only the angular position and velocity of the spacecraft. The global stability of the closed-loop system is guaranteed without having access to the states describing the dynamics of the appendage and with severe saturation in the available torque. Spacecraft apply open-loop thruster firings to induce a desired translational momentum with an extended appendage. This control algorithm will assist this maneuver by stabilizing the attitude dynamics around a desired orientation, and consequently minimize the maneuver execution errors.
Neuromuscular control: introduction and overview.
van Leeuwen, J L
1999-05-29
This paper introduces some basic concepts of the interdisciplinary field of neuromuscular control, without the intention to be complete. The complexity and multifaceted nature of neuromuscular control systems is briefly addressed. Principles of stability and planning of motion trajectories are discussed. Closed-loop and open-loop control are considered, together with the inherent stability properties of muscles and the geometrical design of animal bodies. Various modelling approaches, as used by several authors in the Philosophical Transactions of the Royal Society of London, Series B, May 1999 issue, such as inverse and forward dynamics are outlined. An introductory overview is presented of the other contributions in that issue.
Chopra, I.; Ballard, J. D.
1980-01-01
Recent state-of-the-art techniques in rotor systems include the use of active feedback to augment the dynamic control characteristics of an aircraft system. A recent test of a stoppable rotor with blade circulation blowing was conducted in the Ames Research Center's 40by 80-ft wind tunnel. A major part of the test schedule was dedicated to the acquisition of data to determine the stability of a closed-loop hub-moment feedback control system. Therefore, the open-loop control response was measured at several flight conditions to ascertain the stability of the system prior to the final closed-loop feedback control test. Measurements were made during both the stopped and rotating rotor modes, and open-loop Bode plots were obtained for the control loops associated with the moments about the longitudinal and lateral axis.
Directory of Open Access Journals (Sweden)
Ruili Wen
2016-08-01
Full Text Available We consider an open-loop system of a fourth order Schrodinger equation with variable coefficients and Neumann boundary control and collocated observation. Using the multiplier method on Riemannian manifold we show that that the system is well-posed in the sense of Salamon. This implies that the exponential stability of the closed-loop system under the direct proportional output feedback control and the exact controllability of open-loop system are equivalent. So in order to conclude feedback stabilization from well-posedness, we study the exact controllability under a uniqueness assumption by presenting the observability inequality for the dual system. In addition, we show that the system is regular in the sense of Weiss, and that the feedthrough operator is zero.
An optimal PID controller via LQR for standard second order plus time delay systems.
Srivastava, Saurabh; Misra, Anuraag; Thakur, S K; Pandit, V S
2016-01-01
An improved tuning methodology of PID controller for standard second order plus time delay systems (SOPTD) is developed using the approach of Linear Quadratic Regulator (LQR) and pole placement technique to obtain the desired performance measures. The pole placement method together with LQR is ingeniously used for SOPTD systems where the time delay part is handled in the controller output equation instead of characteristic equation. The effectiveness of the proposed methodology has been demonstrated via simulation of stable open loop oscillatory, over damped, critical damped and unstable open loop systems. Results show improved closed loop time response over the existing LQR based PI/PID tuning methods with less control effort. The effect of non-dominant pole on the stability and robustness of the controller has also been discussed.
Modeling and Simulation of Buck-Boost Converter with Voltage Feedback Control
Directory of Open Access Journals (Sweden)
Zhou Xuelian
2015-01-01
Full Text Available In order to design the control system, it is necessary to have an exact model of buck-boost converter. This paper put forward the transfer function model of buck-boost converter by the state-space average method. The open-loop transfer function model of uncompensated system is deduced according to the mathematic model of the buck-boost converter, the controller is designed according to frequency domain. The phase and magnitude margin of the open-loop system of the buck-boost converter with compensator have both been increased. After compensating, this control system has the advantages of small overshoot and short settling time. It can also improve control system’s real time property and anti-interference ability.
Intelligent Control on Hot Strip Coiling Temperature
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
A new intelligent control scheme for hot strip coiling temperature is presented. In this scheme, the prediction model of finishing temperature and the presetting model of main cooling zone are establish based on BP neural network, the feed-forward open-loop control model of main cooling zone is constructed based on T-S fuzzy neural network, a new improved structure of T-S fuzzy neural network is developed, and the feedback close-loop control model of precision cooling zone is obtained based on fuzzy control. The effectiveness of the proposed scheme has been demonstrated by computer simulation with a satisfactory result.
Institute of Scientific and Technical Information of China (English)
陈伟蓉; 刘奕志; 陈秀琦; 程冰; 刘玉华
2001-01-01
Objective To evaluate the therapeutic effects and safety offlexible open-loop anterior chamber intraocular lens (FOAC-IOL). Methods By ultrasound biomicroscopy, the positions of the haptics of FOAC-IOL in 20 patients (20 eyes) and the relationships of the haptics with iris and anterior chamber angle structures were observed postoperatively to evaluate the impact of these lenses on the structures of ocular anterior segment. Follow-up duration was from 6 to 20 months. Results Among 40 IOL′s haptics, twenty-six haptics were fixed at the recess of the chamber angle ;and other fourteen haptics penetrated the iris and invaded into the ciliary stroma, which caused recurrent uveitis. There was 1 eye with eccentric lens. There were 8 eyes with anterior synechiae of iris, which were related to the haptics of intraocular lens. Conclusions Ultrasound biomicroscopy works well in dynamic observation of the influence of intraocular lens on ocular anterior segment. The haptics of flexible open-loop anterior chamber intraocular lens should be modified.%目的 评价弹性开放襻一体型前房型人工晶状体（anterchamberintraocularlens，AC-IOL）植入术的疗效及其安全性。方法 应用超声生物显微镜观察20例（20只眼）弹性开放襻一体型AC-IOL植入术后患者IOL襻的位置，以及其与虹膜及房角结构的关系，从而评价IOL对眼前段结构的影响。随访时间6～20个月。结果 40个IOL襻中，26个襻固定于房角隐窝；14个襻（8只眼）穿过虹膜侵入至睫状体实质内，并伴有反复发作的葡萄膜炎。术后8只眼虹膜前粘连与IOL襻有关。结论超声生物显微镜检查是动态了解IOL对眼前段结构影响的有效方法。AC-IOL襻的设计有待进一步改进。
Institute of Scientific and Technical Information of China (English)
乐南更; 彭天好; 张川; 许军; 王光洪
2012-01-01
分析变转速泵控马达调速系统转速降落的主要原因,指出系统泄漏和电机机械特性均能引起转速降落,推导出转速降落补偿系数表达式,建立了恒负载时变转速泵控马达调速系统转速降落补偿方法.实验结果表明:在恒负载时,采用所提出的补偿方法能够很好地实现转速降落补偿.%The reasons of motor speed loss in variable-speed pump-control-motor governing system were analyzed. It was pointed out that system leakage and electromotor mechanical properties were the reasons. Speed drop compensation coefficient expression was derived, and the compensation method under constant load in variable-speed pump-control-motor governing system was built. The experiment results show that using this compensation method, motor speed loss in constant load can be compensated.
Depth Impact Control of an Electromagnetic Actuator for High Precision Engraving
2008-01-01
This document presents both the mechanical elements and the motion control of a novel three–axis metal engraving machine. The aim of this work is to improve the conventional high resolution engraving techniques that commonly use expensive piezoelectric actuators with reduced impact depth. Also, it is presented the depth impact control in open loop for an electromagnetic actuator (solenoid). A conical tool is fixed on the mobile part of the solenoid that moves toward the work piece when the so...
Algorithms for Robust Identification and Control of Large Space Structures. Phase 1.
1988-05-14
there is performance degradation. MPC will efficiently generate stabilizing control commands for plants which are open-loop unstable and/or nonminimum...larger beam models were analyzed with basically zero damping, and stabilizing control was achieved. For a sufficient level of input noise and also for...problem discussed above. , ’ . System damping remains an effective means of reducing the system’s internal energy / .and with it, the stabilizing
Institute of Scientific and Technical Information of China (English)
WU Zhen
2005-01-01
In this paper,we use the solutions of forward-backward stochastic differential equations to get the explicit form of the optimal control for linear quadratic stochastic optimal control problem and the open-loop Nash equilibrium point for nonzero sum differential games problem.We also discuss the solvability of the generalized Riccati equation system and give the linear feedback regulator for the optimal control problem using the solution of this kind of Riccati equation system.
Saha, Suman; Das, Saptarshi; Das, Shantanu; Gupta, Amitava
2012-09-01
A novel conformal mapping based fractional order (FO) methodology is developed in this paper for tuning existing classical (Integer Order) Proportional Integral Derivative (PID) controllers especially for sluggish and oscillatory second order systems. The conventional pole placement tuning via Linear Quadratic Regulator (LQR) method is extended for open loop oscillatory systems as well. The locations of the open loop zeros of a fractional order PID (FOPID or PIλDμ) controller have been approximated in this paper vis-à-vis a LQR tuned conventional integer order PID controller, to achieve equivalent integer order PID control system. This approach eases the implementation of analog/digital realization of a FOPID controller with its integer order counterpart along with the advantages of fractional order controller preserved. It is shown here in the paper that decrease in the integro-differential operators of the FOPID/PIλDμ controller pushes the open loop zeros of the equivalent PID controller towards greater damping regions which gives a trajectory of the controller zeros and dominant closed loop poles. This trajectory is termed as "M-curve". This phenomena is used to design a two-stage tuning algorithm which reduces the existing PID controller's effort in a significant manner compared to that with a single stage LQR based pole placement method at a desired closed loop damping and frequency.
Experimentally realizable control fields in quantum Lyapunov control
Yi, X X; Wu, Chunfeng; Feng, X L; Oh, C H
2011-01-01
As a hybrid of techniques from open-loop and feedback control, Lyapunov control has the advantage that it is free from the measurement-induced decoherence but it includes the system's instantaneous message in the control loop. Often, the Lyapunov control is confronted with time delay in the control fields and difficulty in practical implementations of the control. In this paper, we study the effect of time-delay on the Lyapunov control, and explore the possibility of replacing the control field with a pulse train or a bang-bang signal. The efficiency of the Lyapunov control is also presented through examining the convergence time of the controlled system. These results suggest that the Lyapunov control is robust gainst time delay, easy to realize and effective for high-dimensional quantum systems.
Institute of Scientific and Technical Information of China (English)
赵聪; 李耀华; 李子欣; 王平; 楚遵方
2016-01-01
The circulating current of modular multilevel converter ( MMC) makes arm current distorted. It increa⁃ses converter losses and also threatens safe operating of power devices. This paper analyzes the open⁃loop circulat⁃ing current suppression method based on arm energy from two aspects. Firstly, the fundamental of the open⁃loop circulating current suppression algorithm is proved. This paper also proposes general principle of open⁃loop circulat⁃ing current suppression which provides theoretical basis for system design of MMC. Secondly, compared with the actual value modulation algorithm which is easier to implement, the method based on arm energy in this paper has module capacitor voltage self⁃balancing features without additional control. This paper also proves that the open⁃loop circulating current suppression based on arm energy has module voltage self⁃balancing features theoretically. Hence, the global asymptotic stability of the open⁃loop circulating current suppression is proved. Finally, the meth⁃od and its module capacitor voltage self⁃balancing are verified by simulation.%模块化多电平变流器相间环流的存在使得桥臂电流产生畸变，一方面增加了变流器的损耗，另一方面对功率器件的安全工作范围也提出了更高的要求。本文从两个方面分析了开环环流抑制策略的渐进稳定性。首先证明了开环环流抑制策略的基本原理，并在此基础上提出开环环流抑制的一般原理，为模块化多电平变流器开环环流抑制的系统设计提供了理论依据。其次，相比实现起来更为简单的实际值调制环流抑制方法，本文的基于桥臂能量的开环环流抑制策略具有模块电容电压自平衡的特性，无需施加额外的控制；同时，从理论上证明了该开环环流抑制策略具备在不平衡条件下电容电压自平衡的特性，从而证明了该方法的渐近稳定性。最后，通过仿真验证了
Closed-loop Identification for Control of Linear Parameter Varying Systems
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2014-01-01
, closed- loop system identification is more difficult than open-loop identification. In this paper we prove that the so-called Hansen Scheme, a technique known from linear time-invariant systems theory for transforming closed-loop system identification problems into open-loop-like problems, can......This paper deals with system identification for control of linear parameter varying systems. In practical applications, it is often important to be able to identify small plant changes in an incremental manner without shutting down the system and/or disconnecting the controller; unfortunately...... be extended to accommodate linear parameter varying systems as well. We investigate the identified subsystem’s parameter dependency and observe that, under mild assumptions, the identified subsystem is affine in the parameter vector. Various identification methods are compared in direct and Hansen Scheme...
A platform for dynamic simulation and control of movement based on OpenSim and MATLAB.
Mansouri, Misagh; Reinbolt, Jeffrey A
2012-05-11
Numerical simulations play an important role in solving complex engineering problems and have the potential to revolutionize medical decision making and treatment strategies. In this paper, we combine the rapid model-based design, control systems and powerful numerical method strengths of MATLAB/Simulink with the simulation and human movement dynamics strengths of OpenSim by developing a new interface between the two software tools. OpenSim is integrated with Simulink using the MATLAB S-function mechanism, and the interface is demonstrated using both open-loop and closed-loop control systems. While the open-loop system uses MATLAB/Simulink to separately reproduce the OpenSim Forward Dynamics Tool, the closed-loop system adds the unique feature of feedback control to OpenSim, which is necessary for most human movement simulations. An arm model example was successfully used in both open-loop and closed-loop cases. For the open-loop case, the simulation reproduced results from the OpenSim Forward Dynamics Tool with root mean square (RMS) differences of 0.03° for the shoulder elevation angle and 0.06° for the elbow flexion angle. MATLAB's variable step-size integrator reduced the time required to generate the forward dynamic simulation from 7.1s (OpenSim) to 2.9s (MATLAB). For the closed-loop case, a proportional-integral-derivative controller was used to successfully balance a pole on model's hand despite random force disturbances on the pole. The new interface presented here not only integrates the OpenSim and MATLAB/Simulink software tools, but also will allow neuroscientists, physiologists, biomechanists, and physical therapists to adapt and generate new solutions as treatments for musculoskeletal conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.
Gain Scheduling Control based on Closed-Loop System Identification
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
This paper deals with system identification and gain scheduling control of multi-variable nonlinear systems. We propose a novel scheme where a linear approximation of the system model is obtained in an operating point; then, a Youla-Kucera (YJBK) parameter specifying the difference between...... the first and a second operating point is identified in closed-loop using system identification methods with open-loop properties. Next, a linear controller is designed for this linearised model, and gain scheduling control can subsequently be achieved by interpolating between each controller...
Quadratic controller syntheses for the steam generator water level
Energy Technology Data Exchange (ETDEWEB)
Arzelier, D.; Daafouz, J.; Bernussou, J.; Garcia, G
1998-06-01
The steam generator water level, (SGWL), control problem in the pressurized water reactor of a nuclear power plant is considered from robust control techniques point of view. The plant is a time-varying system with a non minimum phase behavior and an unstable open-loop response. The time-varying nature of the plant due to change in operating power is taken into account by including slowly time-varying uncertainty in the model. A linear Time-Invariant, (LTI) guaranteed cost quadratic stabilizing controller is designed in order to address some of the particular issues arising for such a control problem. (author) 17 refs.
Passivity-Based Control of a Rigid Electrodynamic Tether
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2011-01-01
how these periodic solutions can be stabilized by controlling only the current through the tether. A port-controlled Hamiltonian formulation is employed to describe the tethered satellite system and a passive input-output connection is utilized in the control design. The control law consists of two...... parts, a feedback connection, which stabilizes the open-loop equilibrium, and a bias term, which is able to drive the system trajectory away from this equilibrium, a feature necessary to obtain orbit adjustment capabilities of the electrodynamic tether. It is then shown how the periodic solutions...
Directory of Open Access Journals (Sweden)
Ali Reza Sadoughi
2015-03-01
Full Text Available Given the importance of electric machines in the industry with high efficiency, and speed control of this machines are also important, in this paper, three-phase line start permanent magnet synchronous motor and three-phase induction motors that are same in nominal power and the number of poles, is controled, monitored and compared by open-loop voltage to frequency drive, with each other. To this end, simulating the same conditions for the launch of electronic drive with open loop control V/Hz with constant load torque is provided.Simulation results from MATLAB/Simulink software are presented for both line-starting and Adjustable Speed Drive (ASD applications in the same situations, to provide a comprehensive comparison, and it shows a transient and steady-state response of an LSPMSM drive compared to its IM.
Institute of Scientific and Technical Information of China (English)
O. M. Mohamed Vall; R. M'hiri
2008-01-01
Many physical processes have nonlinear behavior which can be well represented by a polynomial NARX or NARMAX model. The identification of such models has been widely explored in literature. The majority of these approaches are for the open-loop identification. However, for reasons such as safety and production restrictions, open-loop identification cannot always be done. In such cases, closed-loop identification is necessary. This paper presents a two-step approach to closed-loop identification of the polynomial NARX/NARMAX systems with variable structure control (VSC). First, a genetic algorithm (GA) is used to maximize the similarity of VSC signal to white noise by tuning the switching function parameters. Second, the system is simulated again and its parameters are estimated by an algorithm of the least square (LS) family. Finally, simulation examples are given to show the validity of the proposed approach.
Overview of progress in quantum systems control
Institute of Scientific and Technical Information of China (English)
CONG Shuang; ZHENG Yisong; JI Beichen; DAI Yi
2007-01-01
The development of the theory on quantum systems control in the last 20 years is reviewed in detail.The research on the controllability of quantum systems is first introduced,then the study on the quantum open-loop control methods often used for controlling simple quantum systems is analyzed briefly.The learning control method and the feedback control method are mainly discussed for they are two important methods in quantum systems control and their advantages and disadvantages are presented.According to the trends in quantum systems control development,the paper predicts the future trends of its development and applications.A complete design procedure necessary for the quantum control system is presented.Finally,several vital problems hindering the advancement of quantum control are pointed out.
Active control of smart structures with optimal actuator and sensor locations
Liu, Pengxiang; Rao, Vittal S.; Derriso, Mark M.
2002-07-01
Sensors and actuators used in active control of smart structures have to be located appropriately in order to ensure maximum control and measurement effectiveness. Many placement techniques are based on the structure itself and overlook the effects of the applied control law. The optimal locations determined from open-loop system can not guarantee the best performance of the closed-loop system because the performance is closely related with the design requirements and applied controller. In this paper, we presented a method of obtaining the optimal locations of actuators/sensors by combining the open-loop and closed-loop optimal criterions. First, for open-loop system, location indices of the controlled modes are calculated on the basis of modal controllability and observability. The controlled modes are weighted based on the controller design requirements. To reduce the spill-over effect of uncontrolled modes, the location index values of uncontrolled modes are added as penalty terms. Locations with high index values are chosen as candidate locations of actuator/sensor for the next determining step on the closed-loop system. Three control techniques, optimal H2, H(infinity ) norms and optimal pole-placement, are utilized for two different control objectives, disturbance rejection and damping property enhancement. Linear matrix inequality (LMI) techniques are utilized to formulate the control problems and synthesize the controllers. For each candidate location of actuator/sensor, a controller is designed and the obtained performance is taken as location index. By solving the location problem in two steps, we reduced the computational burden and ensured good control performance of the closed-loop system. The proposed method is tested on a clamped plate with piezoelectric actuators and sensors.
Control by damping Injection of Electrodynamic Tether System in an Inclined Orbit
DEFF Research Database (Denmark)
Larsen, Martin Birkelund; Blanke, Mogens
2009-01-01
Control of a satellite system with an electrodynamic tether as actuator is a time-periodic and underactuated control problem. This paper considers the tethered satellite in a Hamiltonian framework and determines a port-controlled Hamiltonian formulation that adequately describes the nonlinear...... dynamical system. Based on this model, a nonlinear controller is designed that will make the system asymptotically stable around its open-loop equilibrium. The control scheme handles the time-varying nature of the system in a suitable manner resulting in a large operational region. The performance...
MFM Automatic Control System Development for CYCIAE-100
Institute of Scientific and Technical Information of China (English)
CAO; Lei; YIN; Zhi-guo; LV; Yin-long; ZHONG; Jun-qing
2012-01-01
<正>In order to do the magnetic field measurement (MFM) work for CYCIAE-100, a set of MFM automatic facility has been developed by the cyclotron team at CIAE. 1 Design of project The MFM facility for CYCIAE-100 adopts the method of circular and radial motion to complete the measurement. In circular direction, an open loop control is adopted at hardware level. A kind of arithmetic is compensated to form a virtual closed loop control based on the position signal by angle encoder
Game Theoretic Approach to Post-Docked Satellite Control
Hiramatsu, Takashi; Fitz-Coy, Norman G.
2007-01-01
This paper studies the interaction between two satellites after docking. In order to maintain the docked state with uncertainty in the motion of the target vehicle, a game theoretic controller with Stackelberg strategy to minimize the interaction between the satellites is considered. The small perturbation approximation leads to LQ differential game scheme, which is validated to address the docking interactions between a service vehicle and a target vehicle. The open-loop solution are compared with Nash strategy, and it is shown that less control efforts are obtained with Stackelberg strategy.
Load limiting parachute inflation control
Energy Technology Data Exchange (ETDEWEB)
Redmond, J.; Hinnerichs, T.; Parker, G.
1994-01-01
Excessive deceleration forces experienced during high speed deployment of parachute systems can cause damage to the payload and the canopy fabric. Conventional reefing lines offer limited relief by temporarily restricting canopy inflation and limiting the peak deceleration load. However, the open-loop control provided by existing reefing devices restrict their use to a specific set of deployment conditions. In this paper, the sensing, processing, and actuation that are characteristic of adaptive structures form the basis of three concepts for active control of parachute inflation. These active control concepts are incorporated into a computer simulation of parachute inflation. Initial investigations indicate that these concepts promise enhanced performance as compared to conventional techniques for a nominal release. Furthermore, the ability of each controller to adapt to off-nominal release conditions is examined.
A Novel Control-rod Drive Mechanism via Electromagnetic Levitation in MNSR
Directory of Open Access Journals (Sweden)
Divandari Mohammad
2014-07-01
Full Text Available In this paper, an electromagnetic levitation system was used with a synchronous motor to navigate the control rod of a small-type research reactor. The result from this prototype magnetic levitation system was in agreement with simulation results. The control system was programmed in MATLAB through open-loop system, closed-loop with state feedback and closed-loop with state feedback integral tracking. The final control system showed the highest performance with a low positioning error. Our results showed that the developed control system has the potential to be used as a reliable actuator in nuclear reactors to satisfy higher performance and safety.
Feed forward and feedback control for over-ground locomotion in anaesthetized cats
Mazurek, K. A.; Holinski, B. J.; Everaert, D. G.; Stein, R. B.; Etienne-Cummings, R.; Mushahwar, V. K.
2012-04-01
The biological central pattern generator (CPG) integrates open and closed loop control to produce over-ground walking. The goal of this study was to develop a physiologically based algorithm capable of mimicking the biological system to control multiple joints in the lower extremities for producing over-ground walking. The algorithm used state-based models of the step cycle each of which produced different stimulation patterns. Two configurations were implemented to restore over-ground walking in five adult anaesthetized cats using intramuscular stimulation (IMS) of the main hip, knee and ankle flexor and extensor muscles in the hind limbs. An open loop controller relied only on intrinsic timing while a hybrid-CPG controller added sensory feedback from force plates (representing limb loading), and accelerometers and gyroscopes (representing limb position). Stimulation applied to hind limb muscles caused extension or flexion in the hips, knees and ankles. A total of 113 walking trials were obtained across all experiments. Of these, 74 were successful in which the cats traversed 75% of the 3.5 m over-ground walkway. In these trials, the average peak step length decreased from 24.9 ± 8.4 to 21.8 ± 7.5 (normalized units) and the median number of steps per trial increased from 7 (Q1 = 6, Q3 = 9) to 9 (8, 11) with the hybrid-CPG controller. Moreover, within these trials, the hybrid-CPG controller produced more successful steps (step length ≤ 20 cm ground reaction force ≥ 12.5% body weight) than the open loop controller: 372 of 544 steps (68%) versus 65 of 134 steps (49%), respectively. This supports our previous preliminary findings, and affirms that physiologically based hybrid-CPG approaches produce more successful stepping than open loop controllers. The algorithm provides the foundation for a neural prosthetic controller and a framework to implement more detailed control of locomotion in the future.
Analysis of one dimensional and two dimensional fuzzy controllers
Institute of Scientific and Technical Information of China (English)
Ban Xiaojun; Gao Xiaozhi; Huang Xianlin; Wu Tianbao
2006-01-01
The analytical structures and the corresponding mathematical properties of the one dimensional and two dimensional fuzzy controllers are first investigated in detail.The nature of these two kinds of fuzzy controllers is next probed from the perspective of control engineering. For the one dimensional fuzzy controller, it is concluded that this controller is a combination of a saturation element and a nonlinear proportional controller, and the system that employs the one dimensional fuzzy controller is the combination of an open-loop control system and a closedloop control system. For the latter case, it is concluded that it is a hybrid controller, which comprises the saturation part, zero-output part, nonlinear derivative part, nonlinear proportional part, as well as nonlinear proportional-derivative part, and the two dimensional fuzzy controller-based control system is a loop-varying system with varying number of control loops.
Space Digital Controller for Improved Motor Control
Alves-Nunes, Samuel; Daras, Gaetan; Dehez, Bruno; Maillard, Christophe; Bekemans, Marc; Michel, Raymond
2014-08-01
Performing digital motor control into space equipment is a new challenge. The new DPC (Digital Programmable Controller) is the first chip that we can use as a micro-controller, allowing us to drive motors with digital control schemes. In this paper, the digital control of hybrid stepper motors is considered. This kind of motor is used for solar array rotation and antenna actuation. New digital control technology brings a lot of advantages, allowing an important reduction of thermal losses inside the motor, and a reduction of thermal constraints on power drive electronic components. The opportunity to drive motors with a digital controller also brings many new functionalities like post-failure torque analysis, micro- vibrations and cogging torque reduction, or electro- mechanical damping of solar array oscillations. To evaluate the performance of the system, Field-Oriented Control (FOC) is implemented on a hybrid stepper motor. A test-bench, made of an active load, has been made to emulate the mechanical behaviour of the solar array, by the use of a torsionally-compliant model. The experimental results show that we can drastically reduce electrical power consumption, compared with the currently used open-loop control scheme.
Brown, T. J.; Mccloud, J. L., III
1980-01-01
Weighted multiple linear regression is used to establish a transfer function matrix relationship between higher harmonic control inputs and transducer vibration outputs for a controllable twist rotor. Data used in the regression were taken from the test of a KAMAN controllable twist rotor conducted in the Ames Research Center's 40- by 80-Foot Wind Tunnel in June 1977. Optimal controls to minimize fixed system vibrational levels are calculated using linear quadratic regulatory theory with a control deflection penalty included in the performance criteria. Control sensitivity to changes in control travel, forward speed, and lift and propulsive forces is examined. It is found that the linear transfer matrix is a strong function of forward speed and a weak function of lift and propulsive force. An open-loop strategy is proposed for systems with limited control travel.
Effects of intermediate load on performance limitations in excitation control
Directory of Open Access Journals (Sweden)
Pichai Aree
2008-05-01
Full Text Available The stability of excitation control systems is of great concern in power system operations. In this paper, the effects of intermediate load on performance limitation in excitation control are studied. The results reveal that the open-loop characteristic of synchronous machines flux linkage can be changed from minimum to non-minimum phase at a high level of intermediate load. This change leads to instability of synchronous machines under manual excitation control. A particular emphasis is also given to investigate the fundamental limitations in excitation control, imposed by non-minimum phases with regard to the open-loop right-half-plane (ORHP pole. The study demonstrates the difficulties of excitation control tuning to achieve the desired performance and robustness under the ORHP pole occurrence. Moreover, this paper shows the conditional stability in excitation control loop, where either an increase or decrease of the exciter gain causes a destabilization of the systems stability. Frequency response techniques are used for these investigations.
Saihi, Kaouther; Richard, Jean-Christophe M; Gonin, Xavier; Krüger, Thomas; Dojat, Michel; Brochard, Laurent
2014-01-01
Introduction Hypoxemia and high fractions of inspired oxygen (FiO2) are concerns in critically ill patients. An automated FiO2 controller based on continuous oxygen saturation (SpO2) measurement was tested. Two different SpO2-FiO2 feedback open loops, designed to react differently based on the level of hypoxemia, were compared. The results of the FiO2 controller were also compared with a historical control group. Methods The system measures SpO2, compares with a target range (92% to 96%), and...
A New Method for Modeling and Control of Hybrid Stepper Motors
Directory of Open Access Journals (Sweden)
George Mihalache
2014-09-01
Full Text Available Over time the mathematical models of the hybrid stepper motors (HSM have been developed in various forms. In this paper we propose to use for HSM a model of a two-phase synchronous machine with permanent magnet in which the number of pole pairs is equal to the number of rotor teeth of the HSM. It analyzes the behavior of hybrid stepper motor controlled in open loop. Control signals are obtained by implementing the control sequences:one-phase-on, two-phases-on, half step.
Delayed Feedback Control of Bao Chaotic System Based on Hopf Bifurcation Analysis
Directory of Open Access Journals (Sweden)
Farhad Khellat
2014-11-01
Full Text Available This paper is concerned with bifurcation and chaos control in a new chaotic system recently introduced by Bao et al [9]. First a condition that the system has a Hopf bifurcation is derived. Then by applying delayed feedback controller, the chaotic system is forced to have a stable periodic orbit extracting from chaotic attractor. This is done by making Hopf bifurcation value of the open loop and the closed loop systems identical. Also by suitable tuning of the controller parameters, unstable equilibrium points become stable. Numerical simulations verify the results.
The mechanics and control of pitching manoeuvres in a freely flying hawkmoth (Manduca sexta).
Cheng, Bo; Deng, Xinyan; Hedrick, Tyson L
2011-12-15
Insects produce a variety of exquisitely controlled manoeuvres during natural flight behaviour. Here we show how hawkmoths produce and control one such manoeuvre, an avoidance response consisting of rapid pitching up, rearward flight, pitching down (often past the original pitch angle), and then pitching up slowly to equilibrium. We triggered these manoeuvres via a sudden visual stimulus in front of free-flying hawkmoths (Manduca sexta) while recording the animals' body and wing movements via high-speed stereo videography. We then recreated the wing motions in a dynamically scaled model to: (1) associate wing kinematic changes with pitch torque production and (2) extract the open-loop dynamics of an uncontrolled moth. Next, we characterized the closed-loop manoeuvring dynamics from the observed flight behaviour assuming that hawkmoths use feedback control based on translational velocity, pitch angle and angular velocity, and then compared these with the open-loop dynamics to identify the control strategy used by the moth. Our analysis revealed that hawkmoths produce active pitch torque via changes in mean wing spanwise rotation angle. Additionally, body translations produce passive translational damping and pitch torque, both of which are linearly dependent on the translational velocity. Body rotations produce similar passive forces and torques, but of substantially smaller magnitudes. Our comparison of closed-loop and open-loop dynamics showed that hawkmoths rely largely on passive damping to reduce the body translation but use feedback control based on pitch angle and angular velocity to control their orientation. The resulting feedback control system remains stable with sensory delays of more than two wingbeats.
Vibration suppression during input tracking of a flexible manipulator using a hybrid controller
Indian Academy of Sciences (India)
Ashish Singla; Ashish Tewari; Bhaskar Dasgupta
2015-09-01
The aim of this paper is to investigate the performance of the hybrid controller for end-point vibration suppression of a flexible manipulator, while it is tracking a desired input profile. Due to large structural vibrations, precise control of flexible manipulators is a challenging task. A hybrid controller is used to track large movements of flexible robotic manipulators, which is a combination of inverse dynamics feedforward control, command shaping and linear state feedback control. The case study of a single-link flexible manipulator is considered, where the manipulator is controlled under open-loop as well as closed-loop control scheme. In the open-loop control scheme, the aim is to test the effectiveness of the command shaper in reducing the vibration levels. Moreover, the effect of payload variations on the performance of command shapers and the importance of more robust shapers is demonstrated in this work. Under the closed-loop control scheme, the control objective is to track the large-hub angle trajectory, while maintaining low vibration levels. In comparison to collocated PD control, being reported in the literature, large reductions in tip acceleration levels as well as input torque magnitudes are observed with the proposed hybrid controller.
Directory of Open Access Journals (Sweden)
R. Triggiani
2007-11-01
Full Text Available The present paper deals with (linear Schrödinger equations, of very general form, which are defined on a bounded domain Omega subset R^n. With focus on these dynamics, we shall then discuss and analyze the specific and foundational topic of a-priori energy identities, with the goal of deriving control-theoretic implications. These will include the issue of optimal regularity, as well as the problems of exact controllability (by open loop controls and of uniform stabilization (by closed loop feedback controls.
Vreck, D; Gernaey, K V; Rosen, C; Jeppsson, U
2006-01-01
In this paper, implementation of the Benchmark Simulation Model No 2 (BSM2) within Matlab-Simulink is presented. The BSM2 is developed for plant-wide WWTP control strategy evaluation on a long-term basis. It consists of a pre-treatment process, an activated sludge process and sludge treatment processes. Extended evaluation criteria are proposed for plant-wide control strategy assessment. Default open-loop and closed-loop strategies are also proposed to be used as references with which to compare other control strategies. Simulations indicate that the BM2 is an appropriate tool for plant-wide control strategy evaluation.
Nonlinear analysis and control of a continuous fermentation process
DEFF Research Database (Denmark)
Szederkényi, G.; Kristensen, Niels Rode; Hangos, K.M
2002-01-01
open-loop system properties, to explore the possible control difficulties and to select the system output to be used in the control structure. A wide range of controllers are tested including pole placement and LQ controllers, feedback and input–output linearization controllers and a nonlinear...... controller based on direct passivation. The comparison is based on time-domain performance and on investigating the stability region, robustness and tuning possibilities of the controllers. Controllers using partial state feedback of the substrate concentration and not directly depending on the reaction rate...... are recommended for the simple fermenter. Passivity based controllers have been found to be globally stable, not very sensitive to the uncertainties in the reaction rate and controller parameter but they require full nonlinear state feedback....
Speed Digital Control of Brushless DC Motor Using dsPIC Controller
Directory of Open Access Journals (Sweden)
Gheorghe Băluţă
2014-09-01
Full Text Available This paper presents the digital control of the Brushless DC motor (BLDCM speed. The dsPICDEM MC1 development system (with the dsPIC30F6010A microcontroller and the dsPICDEM MC1L power module, manufactured by Microchip Company, were used. The control program was developed in C programming language. The graphical user interface was realized in LabVIEW 8.6 graphical programming language. For speed control, a digital controller PI type was implemented. Due to digital controller well chosen and well tuned, the system response at speed step variation is very good. Therewith, the experimental results obtained also show a good compensation of disturbance which does not happen in open-loop control.
Implementation of Close Loop Speed Control with VVVF Control and Slip Regulation on LIM
Directory of Open Access Journals (Sweden)
K. Aditya
2014-04-01
Full Text Available Open loop VVVF control has the disadvantage of low output torque when working at low frequency and poor speed precision at different load conditions.Various performance-improving schemes have been proposed for the basic VVVF control by compensating slips occurring in the low frequency range and slips caused by changing loads. Numerous papers have been published on the close loop speed control of rotary induction motor. In this paper a close loop speed control with VVVF control and slip regulation has been implemented for LIM based conveyor belt test Rig which compensates the disadvantages of traditional Volts/Hz control. SIMULINK results are presented to validate the effectiveness of proposed scheme.
A new PID controller design for automatic generation control of hydro power systems
Energy Technology Data Exchange (ETDEWEB)
Khodabakhshian, A.; Hooshmand, R. [Electrical Engineering Department, University of Isfahan (Iran)
2010-06-15
This paper presents a new robust PID controller for automatic generation control (AGC) of hydro turbine power systems. The method is mainly based on a maximum peak resonance specification that is graphically supported by the Nichols chart. The open-loop frequency response curve is tangent to a specified ellipse and this makes the method to be efficient for controlling the overshoot, the stability and the dynamics of the system. Comparative results of this new load frequency controller with a conventional PI one and also with another PID controller design tested on a multimachine power system show the improvement in system damping remarkably. The region of acceptable performance of the new PID controller covers a wide range of operating and system conditions. (author)
DEFF Research Database (Denmark)
Petersen, Lars Norbert; Jørgensen, John Bagterp; Rawlings, James B.
2015-01-01
In this paper, we develop an economically optimizing Nonlinear Model Predictive Controller (E-NMPC) for a complete spray drying plant with multiple stages. In the E-NMPC the initial state is estimated by an extended Kalman Filter (EKF) with noise covariances estimated by an autocovariance least...... squares method (ALS). We present a model for the spray drying plant and use this model for simulation as well as for prediction in the E-NMPC. The open-loop optimal control problem in the E-NMPC is solved using the single-shooting method combined with a quasi-Newton Sequential Quadratic programming (SQP...
Convexity of the Set of Fixed Points Generated by Some Control Systems
Directory of Open Access Journals (Sweden)
Vadim Azhmyakov
2009-01-01
Full Text Available We deal with an application of the fixed point theorem for nonexpansive mappings to a class of control systems. We study closed-loop and open-loop controllable dynamical systems governed by ordinary differential equations (ODEs and establish convexity of the set of trajectories. Solutions to the above ODEs are considered as fixed points of the associated system-operator. If convexity of the set of trajectories is established, this can be used to estimate and approximate the reachable set of dynamical systems under consideration. The estimations/approximations of the above type are important in various engineering applications as, for example, the verification of safety properties.
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2003-01-01
further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop......In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2003-01-01
In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...
Backstepping and sliding mode control hybridized for a prosthetic hand.
Engeberg, Erik D; Meek, Sanford G
2009-02-01
Open loop and force controllers are compared experimentally with three robust parallel force-velocity controllers that are developed for a prosthetic hand. Robust sliding mode, backstepping, and hybrid sliding mode-backstepping (HSMBS) parallel force-velocity controllers are tested by ten able-bodied subjects. Results obtained with a myoelectrically controlled prosthesis indicate that all three robust controllers offer a statistically significant improvement over linear hand prosthesis control schemes. The robust controllers enable the human operators to more easily manipulate a delicate object. Bench top experiments combined with quantitative and qualitative evaluations from ten test subjects reveal the HSMBS controller to be the best choice to improve control of powered prosthetic hands.
Cooperative controls with intermittent communication
Shen, Dan; Chen, Genshe; Cruz, Jose B., Jr.; Pham, Khanh; Blasch, Erik; Lynch, Robert
2010-04-01
In this paper, we propose a solution to the cooperative path planning with limited communication problem in two phases. In the first (offline) phase, a Pareto-optimal path problem is formulated to find a reference path and the graph cuts minimization method is used to speedily calculate the optimal solution. In the second (online) phase, a foraging algorithm is used to dynamically refine the reference path to meet the dynamic constraints of unmanned aerial vehicle (UAVs), during which an open-loop feedback optimal (OLFO) controller is used to estimate the states which may be unavailable due to infrequent battlefield information updates. Furthermore, an adaptive Markov decision process is proposed to deal with intermittent asynchronous information flow. The method is demonstrated in a simulation for a swarm of Unmanned Air Vehicle (UAV) teams with various communication ranges.
Shoemaker, Adam; Grange, Robert W.; Abaid, Nicole; Leonessa, Alexander
2017-01-01
Functional Electrical Stimulation is a promising approach to treat patients by stimulating the peripheral nerves and their corresponding motor neurons using electrical current. This technique helps maintain muscle mass and promote blood flow in the absence of a functioning nervous system. The goal of this work is to control muscle contractions from FES via three different algorithms and assess the most appropriate controller providing effective stimulation of the muscle. An open-loop system and a closed-loop system with three types of model-free feedback controllers were assessed for tracking control of skeletal muscle contractions: a Proportional-Integral (PI) controller, a Model Reference Adaptive Control algorithm, and an Adaptive Augmented PI system. Furthermore, a mathematical model of a muscle-mass-spring system was implemented in simulation to test the open-loop case and closed-loop controllers. These simulations were carried out and then validated through experiments ex vivo. The experiments included muscle contractions following four distinct trajectories: a step, sine, ramp, and square wave. Overall, the closed-loop controllers followed the stimulation trajectories set for all the simulated and tested muscles. When comparing the experimental outcomes of each controller, we concluded that the Adaptive Augmented PI algorithm provided the best closed-loop performance for speed of convergence and disturbance rejection. PMID:28273101
Optimal actuator location of minimum norm controls for heat equation with general controlled domain
Guo, Bao-Zhu; Xu, Yashan; Yang, Dong-Hui
2016-09-01
In this paper, we study optimal actuator location of the minimum norm controls for a multi-dimensional heat equation with control defined in the space L2 (Ω × (0 , T)). The actuator domain is time-varying in the sense that it is only required to have a prescribed Lebesgue measure for any moment. We select an optimal actuator location so that the optimal control takes its minimal norm over all possible actuator domains. We build a framework of finding the Nash equilibrium so that we can develop a sufficient and necessary condition to characterize the optimal relaxed solutions for both actuator location and corresponding optimal control of the open-loop system. The existence and uniqueness of the optimal classical solutions are therefore concluded. As a result, we synthesize both optimal actuator location and corresponding optimal control into a time-varying feedbacks.
Uniformed model of networked control systems with long time delay
Institute of Scientific and Technical Information of China (English)
Zhu Qixin; Liu Hongli; Hu Shousong
2008-01-01
Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network among control system components. Two new concepts including long time delay and short time delay are proposed.The sensor is almost always clock driven. The controller or the actuator is either clock driven or event driven. Four possible driving modes of networked control systems are presented. The open loop mathematic models of networked control systems with long time delay are developed when the system is driven by anyone of the four different modes.The uniformed modeling method of networked control systems with long time delay is proposed. The simulation results are given in the end.
Discrete-Time LPV Current Control of an Induction Motor
DEFF Research Database (Denmark)
Bendtsen, Jan Dimon; Trangbæk, Klaus
2001-01-01
In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is then constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well...... without further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as experimentally on the actual induction motor, both in open-loop current control and when an outer...
Institute of Scientific and Technical Information of China (English)
陈宁; 魏建华; 李福尚; 岳艺明; 吴根茂
2004-01-01
介绍了液体粘性传动(HVD)装置液压系统工作原理,分析了在开环工作模式下,传统HVD装置产生转速不稳定现象的原因;对基于低压电液转换器的HVD装置新型液压控制系统进行了试验研究,试验结果表明,其开环转速稳定性显著提高,满足了实际要求.
Robust Controller Synthesis Based on Circle Criterion
Fuwa, Katsuhiko; Kato, Hiroyuki; Kando, Hisashi
It is well-known that stability margins (gain and phase margins) are important quantitative indicators for evaluating stability in feedback control system synthesis. However, when we use conventional techniques based on such stability margins, it may be difficult to suppress the vibration from high-order modes of mechanical system. This paper proposes the robust controller synthesis which achieves both the conventional stability margins and the second phase margin which is a quantitative indicator for suppressing the vibration. The basic idea is to synthesize controller such that the Nyquist locus of open-loop transfer function encircles the immediate outer side of the circle which is specified by the conventional stability margins and the second phase margin. This is formulated as modified H∞ mixed sensitivity problem with the weighting constants which are decided by the center and radius of the circle.
Adaptive Control Using Residual Mode Filters Applied to Wind Turbines
Frost, Susan A.; Balas, Mark J.
2011-01-01
Many dynamic systems containing a large number of modes can benefit from adaptive control techniques, which are well suited to applications that have unknown parameters and poorly known operating conditions. In this paper, we focus on a model reference direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend this adaptive control theory to accommodate problematic modal subsystems of a plant that inhibit the adaptive controller by causing the open-loop plant to be non-minimum phase. We will augment the adaptive controller using a Residual Mode Filter (RMF) to compensate for problematic modal subsystems, thereby allowing the system to satisfy the requirements for the adaptive controller to have guaranteed convergence and bounded gains. We apply these theoretical results to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine that has minimum phase zeros.
Behavioural system identification of visual flight speed control in Drosophila melanogaster.
Rohrseitz, Nicola; Fry, Steven N
2011-02-06
Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.
Application of new control strategy for sun tracking
Energy Technology Data Exchange (ETDEWEB)
Rubio, F.R.; Ortega, M.G.; Gordillo, F.; Lopez-Martinez, M. [Depto. Ingenieria de Sistemas y Automatica, Escuela Superior de Ingenieros, Universidad de Sevilla, 41092 Sevilla (Spain)
2007-07-15
The application of high concentration solar cells technology allows a significant increase in the amount of energy collected by solar arrays per unit area. However, to make it possible, more severe specifications on the sun pointing error are required. In fact, the performance of solar cells with concentrators decreases drastically if this error is greater than a small value. These specifications are not fulfilled by simple tracking systems due to different sources of errors (e.g., small misalignments of the structure with respect to geographical north) that appear in practice in low cost, domestic applications. This paper presents a control application of a sun tracker that is able to follow the sun with high accuracy without the necessity of either a precise procedure of installation or recalibration. A hybrid tracking system that consists of a combination of open loop tracking strategies based on solar movement models and closed loop strategies using a dynamic feedback controller is presented. Energy saving factors are taken into account, which implies that, among other factors, the sun is not constantly tracked with the same accuracy, to prevent energy overconsumption by the motors. Simulation and experimental results with a low cost two axes solar tracker are exposed, including a comparison between a classical open loop tracking strategy and the proposed hybrid one. (author)
Development of a Lightweight Segmented Deformable Mirror for High-Order Wavefront Control
Bastaits, R.; Alaluf, D.; Horodinca, M.; Romanescu, I.; Burda, I.; Martic, G.; Preumont, A.
2014-06-01
This paper discusses a concept of light weight segmented bimorph mirror for adaptive optics. The first part of the paper discusses the morphing strategy and addresses the ill-conditioning of the Jacobian of the segments which are partly outside the optical pupil. A comparison of various configurations of segmented mirrors is conducted; it is shown that segmentation increases sharply the natural frequency of the system with a limited deterioration of the image quality. The second part of the paper discusses a few technological aspects of the segment design which are critical for space applications, describes a single segment demonstrator and reports on open loop shape control experimental results.
Control of Hybrid System Using Multi-Input Inverter and Maximum Power Point Tracking
Directory of Open Access Journals (Sweden)
N.Sivakumar
2013-07-01
Full Text Available The objective of this paper is to control the Wind/PV hybrid system using Multi-input inverter to get constant output power for different operating conditions. The MPPT also used in this system to get the maximum peak power to the load. The perturbation observation (P&O method is used to accomplish the maximum power point tracking algorithm for input sources. The operating principle of the open loop and closed loop circuit of multi-input inverter is discussed.
Control of Magnetic Bearings for Rotor Unbalance With Plug-In Time-Varying Resonators.
Kang, Christopher; Tsao, Tsu-Chin
2016-01-01
Rotor unbalance, common phenomenon of rotational systems, manifests itself as a periodic disturbance synchronized with the rotor's angular velocity. In active magnetic bearing (AMB) systems, feedback control is required to stabilize the open-loop unstable electromagnetic levitation. Further, feedback action can be added to suppress the repeatable runout but maintain closed-loop stability. In this paper, a plug-in time-varying resonator is designed by inverting cascaded notch filters. This formulation allows flexibility in designing the internal model for appropriate disturbance rejection. The plug-in structure ensures that stability can be maintained for varying rotor speeds. Experimental results of an AMB-rotor system are presented.
Sensorless Control of Permanent Magnet Machine for NASA Flywheel Technology Development
Kenny, Barbara H.; Kascak, Peter E.
2002-01-01
This paper describes the position sensorless algorithms presently used in the motor control for the NASA "in-house" development work of the flywheel energy storage system. At zero and low speeds a signal injection technique, the self-sensing method, is used to determine rotor position. At higher speeds, an open loop estimate of the back EMF of the machine is made to determine the rotor position. At start up, the rotor is set to a known position by commanding dc into one of the phase windings. Experimental results up to 52,000 rpm are presented.
Stability analysis for an Euler-Bernoulli beam under local internal control and boundary observation
Institute of Scientific and Technical Information of China (English)
Junmin WANG; Baozhu GUO; Kunyi YANG
2008-01-01
An Euler-Bernoulli beam system under the local internal distributed control and boundary point observation is studied. An infinite-dimensional observer for the open-loop system is designed. The closed-loop system that is nondissipative is obtained by the estimated state feedback. By a detailed spectral analysis, it is shown that there is a set of generalized eigenfunctions, which forms a Riesz basis for the state space. Consequently, both the spectrum-determined growth condition and exponential stability are concluded.
Closed loop control of ZVS half bridge DC-DC converter with DCS PWM Control
Directory of Open Access Journals (Sweden)
JANAPATI SIVAVARA PRASAD
2012-10-01
Full Text Available
The main drawback of the conventional symmetric control is that both primary switches in the converter operate at hard switching condition. Moreover, during the off-time period of two switches, the oscillation between the transformer leakage inductance and junction capacitance of the switches results in energy dissipation and electromagnetic interference (EMI emissions due to reverse recovery of MOSFETs body diodes. The asymmetric (complementary control was proposed to achieve ZVS operation for HB switches. However, asymmetric stresses distribution on the corresponding components may occur due to the asymmetric duty cycle distribution for the two primary switches. A new control scheme, to be known as duty-cycle shifted PWM (DCS PWM control, is proposed and applied to the conventional HB dc–dc converters to achieve ZVS for both the switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one of the two symmetric PWM driving signals close to the other, such that ZVS may be achieved for the lagging switch due to the shortened resonant interval. Moreover, based on the DCS PWM control, a new half-bridge topology is proposed to achieve ZVS for both the main switches and auxiliary switch by adding an auxiliary switch and diode in the proposed half bridge. ZVS for the switch is achieved by utilizing the energy trapped in the leakage inductance. There are two control schemes. One is open loop and the other is closed loop. In open loop scheme, the given dc-dc converter is operating under disturbance. This disturbance effect is eliminated in closed loop scheme.
Guerrero, Javier; Guisasola, Albert; Baeza, Juan A
2014-01-01
This work shows the development and the in silico evaluation of a novel control strategy aiming at successful biological phosphorus removal in a wastewater treatment plant operating in an A(2)/O configuration with carbon-limited influent. The principle of this novel approach is that the phosphorus in the effluent can be controlled with the nitrate setpoint in the anoxic reactor as manipulated variable. The theoretical background behind this control strategy is that reducing nitrate entrance to the anoxic reactor would result in more organic matter available for biological phosphorus removal. Thus, phosphorus removal would be enhanced at the expense of increasing nitrate in the effluent (but always below legal limits). The work shows the control development, tuning and performance in comparison to open-loop conditions and to two other conventional control strategies for phosphorus removal based on organic matter and metal addition. It is shown that the novel proposed strategy achieves positive nutrient removal results with similar operational costs to the other control strategies and open-loop operation.
Durability investigation on torque control of a magneto-rheological brake: experimental work
Kim, Wan Ho; Park, Jhin Ha; Kim, Gi-Woo; Shin, Cheol Soo; Choi, Seung-Bok
2017-03-01
This study experimentally investigates the torque control durability of a disc brake featuring a magneto-rheological (MR) fluid. An appropriate size of MR disc brake is designed based on a mathematical model, and a prototype is manufactured. A small-scale laboratory-scale test bed is then developed using a DC motor, in-line torque sensor, and the MR brake. S45C and S20C steels are inserted into a tapered hole on the surface of the brake disc. After 105 cycles of operation in shear mode, the wear properties of the MR brake are characterized by average surface roughness measurements, scanning electron microscope images, and energy dispersive x-ray spectra. The torque control performances before and after the operation cycles are examined using open-loop control and closed-loop proportional-integral-derivative control. As expected, the control performance degraded after 105 cycles of operation in the open-loop case, but not in the closed-loop case. This aspect is demonstrated by the sinusoidal torque-tacking control performance before and after the operation cycles.
Dwyer Cianciolo, Alicia; Powell, Richard W.
2017-01-01
Precision landing on Mars is a challenge. All Mars lander missions prior to the 2012 Mars Science Laboratory (MSL) had landing location uncertainty ellipses on the order of hundreds of kilometers. Sending humans to the surface of Mars will likely require multiple landers delivered in close proximity, which will in turn require orders of magnitude improvement in landing accuracy. MSL was the first Mars mission to use an Apollo-derived bank angle guidance to reduce the size of the landing ellipse. It utilized commanded bank angle magnitude to control total range and bank angle reversals to control cross range. A shortcoming of this bank angle guidance is that the open loop phase of flight created by use of bank reversals increases targeting errors. This paper presents a comparison of entry, descent and landing performance for a vehicle with a low lift-to-drag ratio using both bank angle control and an alternative guidance called Direct Force Control (DFC). DFC eliminates the open loop flight errors by directly controlling two forces independently, lift and side force. This permits independent control of down range and cross range. Performance results, evaluated using the Program to Optimize Simulated Trajectories (POST2), including propellant use and landing accuracy, are presented.
Energy Technology Data Exchange (ETDEWEB)
Marcelino, M.A.; Silva, G.B.S.; Grandinetti, F.J. [Universidade Estadual Paulista (UNESP), Guaratingueta, SP (Brazil). Fac. de Engenharia; Universidade de Taubate (UNITAU), SP (Brazil)], Emails: abud@feg.unesp.br, gabonini@yahoo.com.br, grandinetti@unitau.br
2009-07-01
This paper presents a technique for speed control three-phase induction motor using the pulse width modulation (PWM), in open loop while maintaining the tension for constant frequency. The technique is adapted from a thesis entitled 'Control of the three-phase induction motor, using discrete PWM generation, optimized and synchronized', where studies are presented aimed at their application in home appliances, to eliminate mechanical parts, replaced by low cost electronic control, thus having a significant reduction in power consumption. Initially the experiment was done with the Intel 80C31 micro controller. In this paper, the PWM modulation is implemented using a PIC micro controller, and the speed control kept a low profile, based on tables, synchronized with transitions and reduced generation of harmonics in the network. Confirmations were made using the same process of building tables, but takes advantage of the program of a RISC device.
Metrics of Balance Control for Use in Screening Tests of Vestibular Function
Fiedler, Matthew; Cohen, Helen; Mulavara, Ajitkumar; Peters, Brian; Miller, Chris; Bloomberg, Jacob
2011-01-01
Decrements in balance control have been documented in astronauts after space flight. Reliable measures of balance control are needed for use in postflight field tests at remote landing sites. Diffusion analysis (DA) is a statistical mechanical tool that shows the average difference of the dependent variable on varying time scales. These techniques have been shown to measure differences in open-loop and closed-loop postural control in astronauts and elderly subjects. The goal of this study was to investigate the reliability of these measures of balance control. Eleven subjects were tested using the Clinical Test of Sensory Interaction on Balance: the subject stood with feet together and arms crossed on a stable or compliant surface, with eyes open or closed and with or without head movements in the pitch or yaw plane. Subjects were instrumented with inertial motion sensors attached to their trunk segment. The DA curves for linear acceleration measures were characterized by linear fits measuring open- (Ds) and closed-loop (Dl) control, and their intersection point (X-int, Y-int). Ds and Y-int showed significant differences between the test conditions. Additionally, Ds was correlated with the root mean square (RMS) of the signal, indicating that RMS was dominated by open-loop events (balance stability during field tests.
Distributed control for COFS 1
Montgomery, R. C.; Sulla, Jeff; Lindner, D. K.
1986-01-01
An overview is given of the work being done at NASA LaRC on developing the Control of Flexible Structures (COFS) 1 Flight Experiment Baseline Control Law. This control law currently evolving to a generic control system software package designed to supply many, but not all, guest investigators. A system simulator is also described. It is currently being developed for COFS-1 and will be used to develop the Baseline Control Law and to evaluate guest investigator control schemes. It will be available for use whether or not control schemes fall into the category of the Baseline Control Law. First, the hardware configuration for control experiments is described. This is followed by a description of the simulation software. Open-loop sinusoid excitation time histories are next presented both with and without a local controller for the Linear DC Motor (LDCM) actuators currently planned for the flight. The generic control law follows and algorithm processing requirements are cited for a nominal case of interest. Finally, a closed-loop simulation study is presented, and the state of the work is summarized in the concluding remarks.
Series pid pitch controller of large wind turbines generator
Directory of Open Access Journals (Sweden)
Micić Aleksandar D.
2015-01-01
Full Text Available For this stable process with oscillatory dynamics, characterized with small damping ratio and dominant transport delay, design of the series PID pitch controller is based on the model obtained from the open-loop process step response, filtered with the second-order Butterworth filter Fbw. Performance of the series PID pitch controller, with the filter Fbw, is analyzed by simulations of the set-point and input/output disturbance responses, including simulations with a colored noise added to the control variable. Excellent performance/robustness tradeoff is obtained, compared to the recently proposed PI pitch controllers and to the modified internal model pitch controller, developed here, which has a natural mechanism to compensate effect of dominant transport delay. [Projekat Ministarstva nauke Republike Srbije, br. III 47016
Method and System for Active Noise Control of Tiltrotor Aircraft
Betzina, Mark D. (Inventor); Nguyen, Khanh Q. (Inventor)
2003-01-01
Methods and systems for reducing noise generated by rotating blades of a tiltrotor aircraft. A rotor-blade pitch angle associated with the tiltrotor aircraft can be controlled utilizing a swashplate connected to rotating blades of the tiltrotor aircraft. One or more Higher Harmonic Control (HHC) signals can be transmitted and input to a swashplate control actuator associated with the swashplate. A particular blade pitch oscillation (e.g., four cycles per revolution) is there-after produced in a rotating frame of reference associated with the rotating blades in response to input of an HHC signal to the swashplate control actuator associated with the swashplate to thereby reduce noise associated with the rotating blades of the tiltrotor aircraft. The HHC signal can be transmitted and input to the swashplate control actuator to reduce noise of the tiltrotor aircraft in response to a user input utilizing an open-loop configuration.
Variable structure control of nonlinear systems through simplified uncertain models
Sira-Ramirez, Hebertt
1986-01-01
A variable structure control approach is presented for the robust stabilization of feedback equivalent nonlinear systems whose proposed model lies in the same structural orbit of a linear system in Brunovsky's canonical form. An attempt to linearize exactly the nonlinear plant on the basis of the feedback control law derived for the available model results in a nonlinearly perturbed canonical system for the expanded class of possible equivalent control functions. Conservatism tends to grow as modeling errors become larger. In order to preserve the internal controllability structure of the plant, it is proposed that model simplification be carried out on the open-loop-transformed system. As an example, a controller is developed for a single link manipulator with an elastic joint.
Review of multilevel voltage source inverter topologies and control schemes
Energy Technology Data Exchange (ETDEWEB)
Colak, Ilhami [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey); Kabalci, Ersan, E-mail: kabalci@nevsehir.edu.t [Department of Technical Programs, Vocational Collage of Haci Bektas, Nevsehir University, Hacibektas, Nevsehir 50800 (Turkey); Bayindir, Ramazan [Department of Electrical Education, Faculty of Technical Education, Gazi University, Besevler, Ankara 06500 (Turkey)
2011-02-15
In this study, the most common multilevel inverter topologies and control schemes have been reviewed. Multilevel inverter topologies (MLIs) are increasingly being used in medium and high power applications due to their many advantages such as low power dissipation on power switches, low harmonic contents and low electromagnetic interference (EMI) outputs. The selected switching technique to control the inverter will also have an effective role on harmonic elimination while generating the ideal output voltage. Intensive studies have been performed on carrier-based, sinusoidal, space vector and sigma delta PWM methods in open loop control of inverters. The selection of topology and control techniques may vary according to power demands of inverter. This paper and review results constitute a useful basis for matching of inverter topology and the best control scheme according to various application areas.
Indian Academy of Sciences (India)
SOURABH PAITANDI; MAINAK SENGUPTA
2017-08-01
This paper presents a novel, reliable and efficient V/f control implementation on a 8-pole, 750 rpm, 5 kW surface-mounted permanent magnet synchronous motor (PMSM) without damper winding. In the absence of a damper winding, open loop V/f control of SM is inherently unstable, particularly at high speeds. Stabilisationcan be done with proper stator frequency modulation in accordance with the change in rotor speed to provide for effect of damping. This has been implemented here without use of any shaft-mounted encoder. The change in rotor speed is observed from power perturbation, thereby eliminating the need for using a speed sensor in the drive. The efficiency of the drive is further increased with appropriate control of the power factor, irrespective of load and frequency variations. Simulated and experimental results are presented for both open loop and the proposed V/f control. These results establish the accuracy of the design of the proposed V/f control strategy and the precision of hardware implementation. A comparative study between the proposed V/f control method and standard vector control method, as implemented on this PMSM, has also been presented here to establish the advantages of the proposed scheme. The PMSM itself was designed and fabricated in the laboratory.
Low-level finite state control of knee joint in paraplegic standing.
Mulder, A J; Veltink, P H; Boom, H B; Zilvold, G
1992-01-01
Low-level finite state (locked-unlocked) control is compared with open-loop stimulation of the knee extensor muscles in functional electrical stimulation (FES) induced paraplegic standing. The parameters were: duration of standing, relative torque loss in knee extensor muscles, knee angle stability, average stimulus output and average arm effort during standing. To investigate the impact of external mechanical conditions on controller performance, experiments were performed both under the condition of a freely moving ankle joint and of a mechanically stabilized ankle joint. Finite state control resulted in a 2.5 to 12 times increase of standing duration or in a 1.5 to 5 times decrease of relative torque loss in comparison with open-loop stimulation. Finite state control induced a limit cycle oscillation in the knee joint. Average maximum knee flexion was 6.2 degrees without ankle bracing, and half that value with ankle bracing. Average arm support was 13.9 and 7.5% of the body weight without and with ankle bracing respectively.
Stewart, E. C.; Brown, P. W.
1985-01-01
An automatic trim system for reducing the control forces after an engine failure on a light twin has been investigated on the Langley General Aviation Simulator. The system schedules open-loop trim tab deflections as a function of differential propeller slipstream dynamic pressure and freestream dynamic pressure. The system is described and the airplane-system static and dynamic characteristics are documented. Three NASA research pilots evaluated the effectiveness of the system for takeoff and landing maneuvers. A variety of off-nominal system characteristics were studied. The system was judged to be generally beneficial, providing a 2 to 3 point improvement in pilot rating for the tasks used in the evaluations.
Stewart, E. C.; Brown, P. W.
1985-01-01
An automatic trim system for reducing the control forces after an engine failure on a light twin has been investigated on the Langley General Aviation Simulator. The system schedules open-loop trim tab deflections as a function of differential propeller slipstream dynamic pressure and freestream dynamic pressure. The system is described and the airplane-system static and dynamic characteristics are documented. Three NASA research pilots evaluated the effectiveness of the system for takeoff and landing maneuvers. A variety of off-nominal system characteristics were studied. The system was judged to be generally beneficial, providing a 2 to 3 point improvement in pilot rating for the tasks used in the evaluations.
Myoelectric hand prosthesis force control through servo motor current feedback.
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.
Time-Inconsistent Stochastic Linear--Quadratic Control
Hu, Ying; Zhou, Xun Yu
2011-01-01
In this paper, we formulate a general time-inconsistent stochastic linear--quadratic (LQ) control problem. The time-inconsistency arises from the presence of a quadratic term of the expected state as well as a state-dependent term in the objective functional. We define an equilibrium, instead of optimal, solution within the class of open-loop controls, and derive a sufficient condition for equilibrium controls via a flow of forward--backward stochastic differential equations. When the state is one dimensional and the coefficients in the problem are all deterministic, we find an explicit equilibrium control. As an application, we then consider a mean-variance portfolio selection model in a complete financial market where the risk-free rate is a deterministic function of time but all the other market parameters are possibly stochastic processes. Applying the general sufficient condition, we obtain explicit equilibrium strategies when the risk premium is both deterministic and stochastic.
Temperature uniformity control in RTP using multivariable adaptive control
Energy Technology Data Exchange (ETDEWEB)
Morales, S.; Dahhou, B.; Dilhac, J.M. [Centre National de la Recherche Scientifique (CNRS), 31 - Toulouse (France); Morales, S.
1995-12-31
In Rapid Thermal Processing (RTP) control of the wafer temperature during all processing to get good trajectory following, together with spatial temperature uniformity, is essential. It is well know as RTP process is nonlinear, classical control laws are not very efficient. In this work, the authors aim at studying the applicability of MIMO (Multiple Inputs Multiple Outputs) adaptive techniques to solve the temperature control problems in RTP. A multivariable linear discrete time CARIMA (Controlled Auto Regressive Integrating Moving Average) model of the highly non-linear process is identified on-line using a robust identification technique. The identified model is used to compute an infinite time LQ (Linear Quadratic) based control law, with a partial state reference model. This reference model smooths the original setpoint sequence, and at the same time gives a tracking capability to the LQ control law. After an experimental open-loop investigation, the results of the application of the adaptive control law are presented. Finally, some comments on the future difficulties and developments of the application of adaptive control in RTP are given. (author) 13 refs.
Shape and vibration control of active laminated plates for RF and optical applications
Punhani, Amitesh; Washington, Gregory N.
2006-03-01
Active shape and vibration control of large structures have long been desired for many practical applications. PVDF being one of the most suitable materials for these applications due to its strong piezoelectric properties and availability in thin sheets has been the focal point of most researchers in this area. Most of the research has been done to find an open loop solution, which would be able to shape the structure as per the desired requirements in an ideal atmosphere. Unmodeled dynamics and external disturbances prevent the open loop (no feedback) solution from achieving the desired shape. This research develops a dynamic model of a laminated plate consisting of two layers of PVDF film joined with a layer of epoxy. The orthotropic properties of PVDF have been modeled and the epoxy layer is considered to be isotropic. A general control model is developed, which would work for most boundary conditions and developed for a simply supported beam with patch actuators. The methodology is then extended for a simply supported laminated plate. This model could be used for real time dynamic disturbance rejection and shape and vibration control of the structure.
Postural control model interpretation of stabilogram diffusion analysis
Peterka, R. J.
2000-01-01
Collins and De Luca [Collins JJ. De Luca CJ (1993) Exp Brain Res 95: 308-318] introduced a new method known as stabilogram diffusion analysis that provides a quantitative statistical measure of the apparently random variations of center-of-pressure (COP) trajectories recorded during quiet upright stance in humans. This analysis generates a stabilogram diffusion function (SDF) that summarizes the mean square COP displacement as a function of the time interval between COP comparisons. SDFs have a characteristic two-part form that suggests the presence of two different control regimes: a short-term open-loop control behavior and a longer-term closed-loop behavior. This paper demonstrates that a very simple closed-loop control model of upright stance can generate realistic SDFs. The model consists of an inverted pendulum body with torque applied at the ankle joint. This torque includes a random disturbance torque and a control torque. The control torque is a function of the deviation (error signal) between the desired upright body position and the actual body position, and is generated in proportion to the error signal, the derivative of the error signal, and the integral of the error signal [i.e. a proportional, integral and derivative (PID) neural controller]. The control torque is applied with a time delay representing conduction, processing, and muscle activation delays. Variations in the PID parameters and the time delay generate variations in SDFs that mimic real experimental SDFs. This model analysis allows one to interpret experimentally observed changes in SDFs in terms of variations in neural controller and time delay parameters rather than in terms of open-loop versus closed-loop behavior.
Coherent feedback control of a single qubit in diamond
Hirose, Masashi; Cappellaro, Paola
2016-04-01
Engineering desired operations on qubits subjected to the deleterious effects of their environment is a critical task in quantum information processing, quantum simulation and sensing. The most common approach relies on open-loop quantum control techniques, including optimal-control algorithms based on analytical or numerical solutions, Lyapunov design and Hamiltonian engineering. An alternative strategy, inspired by the success of classical control, is feedback control. Because of the complications introduced by quantum measurement, closed-loop control is less pervasive in the quantum setting and, with exceptions, its experimental implementations have been mainly limited to quantum optics experiments. Here we implement a feedback-control algorithm using a solid-state spin qubit system associated with the nitrogen vacancy centre in diamond, using coherent feedback to overcome the limitations of measurement-based feedback, and show that it can protect the qubit against intrinsic dephasing noise for milliseconds. In coherent feedback, the quantum system is connected to an auxiliary quantum controller (ancilla) that acquires information about the output state of the system (by an entangling operation) and performs an appropriate feedback action (by a conditional gate). In contrast to open-loop dynamical decoupling techniques, feedback control can protect the qubit even against Markovian noise and for an arbitrary period of time (limited only by the coherence time of the ancilla), while allowing gate operations. It is thus more closely related to quantum error-correction schemes, although these require larger and increasing qubit overheads. Increasing the number of fresh ancillas enables protection beyond their coherence time. We further evaluate the robustness of the feedback protocol, which could be applied to quantum computation and sensing, by exploring a trade-off between information gain and decoherence protection, as measurement of the ancilla-qubit correlation
Beyond the PI Controllers in First-Order Time-Delay Systems
Martelli, Gianpasquale
2007-01-01
In this paper the following three control systems for first-order time-delay plants are studied and compared: the feedback proportional-integral controller (PI), the Smith Predictor (SP) and a proposed variable structure consisting of two blocks. This structure acts as an open-loop proportional controller, after a setpoint change, and as a closed-loop integrating controller, when the error enters in a preset band. A chart, provided with the borderlines of the stability zone and with the curves of two design parameters, is implemented for each controller. The first parameter is the overshoot of the controlled variable, evaluated during a step change of the setpoint and made equal to a preset value. The second parameter, only for the PI and SP controllers, is the integral of the squared error (ISE), which must have the minimum allowable value. The ISE is also assumed as comparison index and the proposed controller appears as the best.
Control, operator support and safety system of PVC reactors
Energy Technology Data Exchange (ETDEWEB)
Ytreeide, J.I.; Aaker, O.; Kristoffersen, V.; Moe, G.; Naustdal, C.
1997-06-01
In modern petrochemical plants the corporate and societal demands to plant safety and minimum environmental effects are high. These demands rise high performance requirements to the technical systems, specially the process control and safety systems including an effective operator support system with fault detection capability. PVC producing plants have high inherent hazard potentials, and the studied reaction in this publication is exothermic and non-linear and open-loop unstable, and the plant is equipped with two independent cooling systems to keep the reaction under control. A system to solve the stability problem of parallel control is suggested, showing the simulation of real process data. The publication describes an operator support system for monitoring the heat of reaction in the autoclave consisting of a model based estimator. The system is tested on-line, and the results of simulations and on-line estimates are presented. 6 refs., 13 figs.
Smith, G. A.; Meyer, G.
1980-01-01
The results of a simulation study of an alternative design concept for an automatic landing control system are presented. The alternative design concept for an automatic landing control system is described. The design concept is the total aircraft flight control system (TAFCOS). TAFCOS is an open loop, feed forward system that commands the proper instantaneous thrust, angle of attack, and roll angle to achieve the forces required to follow the desired trajector. These dynamic trim conditions are determined by an inversion of the aircraft nonlinear force characteristics. The concept was applied to an A-7E aircraft approaching an aircraft carrier. The implementation details with an airborne digital computer are discussed. The automatic carrier landing situation is described. The simulation results are presented for a carrier approach with atmospheric disturbances, an approach with no disturbances, and for tailwind and headwind gusts.
Design of a 2-DOF Control and Disturbance Estimator for a Magnetic Levitation System
Directory of Open Access Journals (Sweden)
A. Pati
2017-02-01
Full Text Available This work proposes a systematic two-degree freedom control scheme to improve the reference input tracking and load disturbance rejection for an unstable magnetic levitation system. The proposed control strategy is a two-step design process. Firstly, a proportional derivative controller is introduced purposely to get the desired set-point response of the magnetic levitation system and then, an integral square error (ISE performance specification is used for designing a set-point tracking controller. Secondly, a disturbance estimator is designed using the desired closed loop complimentary sensitivity function for the rejection of load disturbances. This leads to the decoupling of the nominal set-point response from the load disturbance response similar to an open loop control manner. Thus, it is convenient to optimize both controllers simultaneously as well as separately. The effectiveness of the proposed control strategy is validated through simulation.
A Nonlinear Physics-Based Optimal Control Method for Magnetostrictive Actuators
Smith, Ralph C.
1998-01-01
This paper addresses the development of a nonlinear optimal control methodology for magnetostrictive actuators. At moderate to high drive levels, the output from these actuators is highly nonlinear and contains significant magnetic and magnetomechanical hysteresis. These dynamics must be accommodated by models and control laws to utilize the full capabilities of the actuators. A characterization based upon ferromagnetic mean field theory provides a model which accurately quantifies both transient and steady state actuator dynamics under a variety of operating conditions. The control method consists of a linear perturbation feedback law used in combination with an optimal open loop nonlinear control. The nonlinear control incorporates the hysteresis and nonlinearities inherent to the transducer and can be computed offline. The feedback control is constructed through linearization of the perturbed system about the optimal system and is efficient for online implementation. As demonstrated through numerical examples, the combined hybrid control is robust and can be readily implemented in linear PDE-based structural models.
Temperature Control of Heating Zone for Drying Process: Effect of Air Velocity Change
Directory of Open Access Journals (Sweden)
Wutthithanyawat Chananchai
2016-01-01
Full Text Available This paper proposes a temperature control technique to adjust air temperature in a heating zone for drying process. The controller design is achieved by using an internal model control (IMC approach. When the IMC controller parameters were designed by calculating from an actual process transfer function estimated through an open-loop step response with input step change from 50% to 60% at a reference condition at air velocity of 1.20 m/s, the performance of temperature controller was experimentally tested by varying an air velocity between 1.32 m/s and 1.57 m/s, respectively. The experimental results showed that IMC controller had a high competency for controlling the drying temperature.
Modeling and Control of a Double-effect Absorption Refrigerating Machine
Hihara, Eiji; Yamamoto, Yuuji; Saito, Takamoto; Nagaoka, Yoshikazu; Nishiyama, Noriyuki
Because the heat capacity of absorption refrigerating machines is large compared with vapor compression refrigerating machines, the dynamic characteristics at the change in cooling load conditions are problems to be improved. The control method of energy input and of weak solution flow rate following cooling load variations was investigated. As the changes in cooling load and cooling capacity are moderate, the optimal operation conditions corresponding to the cooling load can be estimated with steady state characteristics. If the relation between the cooling load and the optimal operation conditions is well known, a feed forward control can be employed. In this report a new control algorithm, which is called MOL (Multi-variable Open Loop) control, is proposed. Comparing the MOL control with the conventional chilled water outlet temperature proportional control, the MOL control enables the smooth changes in cooling capacity and the reduction in fuel consumption.
Dynamic control of modeled tonic-clonic seizure states with closed-loop stimulation
Directory of Open Access Journals (Sweden)
Bryce eBeverlin II
2013-02-01
Full Text Available Seizure control using deep brain stimulation (DBS provides an alternative therapy to patients with intractable and drug resistant epilepsy. This paper presents novel DBS stimulus protocols to disrupt seizures. Two protocols are presented: open-loop stimulation and a closed-loop feedback system utilizing measured firing rates to adjust stimulus frequency. Stimulation suppression is demonstrated in a computational model using 3000 excitatory Morris-Lecar model neurons connected with depressing synapses. Cells are connected using second order network topology to simulate network topologies measured in cortical networks. The network spontaneously switches from tonic to clonic as synaptic strengths and tonic input to the neurons decreases. To this model we add periodic stimulation pulses to simulate DBS. Periodic forcing can synchronize or desynchronize an oscillating population of neurons, depending on the stimulus frequency and amplitude. Therefore, it is possible to either extend or truncate the tonic or clonic phases of the seizure. Stimuli applied at the firing rate of the neuron generally synchronize the population while stimuli slightly slower than the firing rate prevent synchronization. We present an adaptive stimulation algorithm that measures the firing rate of a neuron and adjusts the stimulus to maintain a relative stimulus frequency to firing frequency and demonstrate it in a computational model of a tonic-clonic seizure. This adaptive algorithm can affect the duration of the tonic phase using much smaller stimulus amplitudes than the open-loop control.
Institute of Scientific and Technical Information of China (English)
宋亚林
2015-01-01
This paper discusses the hydraulic open loop and closed loop system and its characteristics of synchronous control. The Application of hydraulic closed loop synchronization control system in hydraulic type three roller symmetrical bending machine was introduced in this paper.%论述了液压开环与闭环同步控制系统及其特点，并对液压闭环同步控制系统在液压式三辊对称卷板机中的应用进行了介绍。
一种船用液压舵机控制系统设计%Design of Hydraulic Servo Control System for Ship
Institute of Scientific and Technical Information of China (English)
汪永生; 王洪波
2014-01-01
Aiming at small and medium ships,an open-loop type hydraulic servo control system was designed which had a simple structure and taking up small space. Adopting the system,the rudder machine works more steadily.%针对中小型船舶，设计一种结构简单、占用空间小的开式回路液压控制系统，同时采用了回油节流调速回路，使得舵机工作比较平稳。
Carson, John M., III; Ackmese, A. Behcet
2005-01-01
The guidance and control (G&C) algorithms for enabling small-body proximity operations are developed by using a model predictive control approach along with a convexification of the governing dynamics, control constraints, and trajectory/state constraints. The open-loop guidance is solved ahead of time or in a resolvable, real-time manner through the use of PWG (Pseudo Way-point Generation), a technique developed in this research. The PWG scheme ensures required thruster silent times during trajectory maneuvers. The feedback control is implemented to track the PWG trajectories in a manner that guarantees the resolvability for the open-loop problem, enabling the ability to update the G&C in a model-predictive manner. The schemes incorporate gravity models and thruster ring times into discrete dynamics that are solved as a optimal control problem to minimize fuel consumption or thruster energy expenditure. The optimal control problem is cast as an LMI (Linear Matrix Inequality) and then solved through Semi-Definite Programming techniques in a computationally efficient manner that provides convergence and constraint guarantees.
Schroedter, Richard; Schwarzenberg, Markus; Dreyhaupt, André; Barth, Robert; Sandner, Thilo; Janschek, Klaus
2017-02-01
In this paper we present a 2D raster scanning quasi-static/resonant micro mirror being controlled in both axes in closed-loop with on-chip piezo-resistive sensor feedback. While the resonant axis oscillates with a given frequency, the quasi-static axis allows static as well as dynamic deflection up to its eigenfrequency because of its staggered vertical comb (SVC) drive arrangement. Due to the high quality factor of the very low damped spring-masssystem, an adapted trajectory planning using jerk limitation is applied for the quasi-static axis [1]. Nevertheless, inaccuracies of the applied nonlinear micro mirror model and external disturbances lead to undesired residual oscillation in open-loop control mode. To achieve high precise and fast beam positioning, we implement a flatness-based control algorithm with feedback to on-chip piezo-resistive deflection sensors. In comparison to previous work [2, 3], we developed a micro controller setup for driving the microscanner, that is equipped with an analog Bessel filter increasing the sensor signal quality significantly. In this study we demonstrate a small size and low power micro mirror driver including high-voltage generation and a microcontroller for real-time control as well as a head circuit board for high resolution sensing. We discuss experimental results of open-loop and closed-loop control for 2D raster scanning operation. Finally, the outlook is given to the intrinsic capability to compensate temperature drifts influencing the piezo-resistive sensor signal.
Industrial Process Identification and Control Design Step-test and Relay-experiment-based Methods
Liu, Tao
2012-01-01
Industrial Process Identification and Control Design is devoted to advanced identification and control methods for the operation of continuous-time processes both with and without time delay, in industrial and chemical engineering practice. The simple and practical step- or relay-feedback test is employed when applying the proposed identification techniques, which are classified in terms of common industrial process type: open-loop stable; integrating; and unstable, respectively. Correspondingly, control system design and tuning models that follow are presented for single-input-single-output processes. Furthermore, new two-degree-of-freedom control strategies and cascade control system design methods are explored with reference to independently-improving, set-point tracking and load disturbance rejection. Decoupling, multi-loop, and decentralized control techniques for the operation of multiple-input-multiple-output processes are also detailed. Perfect tracking of a desire output trajectory is realiz...
Variable Displacement Control of the Concrete Pumping System Based on Dynamic Programming
Directory of Open Access Journals (Sweden)
Ye Min
2017-01-01
Full Text Available To solve the problems of cylinder piston striking cylinder and the hydraulic shocking of the main pump, and causing energy waste problem, the method of variable displacement control of piston stroke was proposed. In order to achieve effective control of the piston stroke, variable displacement control model was established under the physical constraint condition of non-collision between piston and cylinder. And the control process was realized by Dynamic Programming(DP, the simulation and test results show that piston of concrete pumping system don’t strike cylinder and reduce the hydraulic shock of the main pump outlet, meanwhile improve the response speed of the cylinder and achieve energy-saving purposes under varying loads. This control model built in the integration design space of structure variable and control variable is of guiding significance for solving open-loop system’s engineering problems.
Design of PID controllers in double feedback loops for SISO systems with set-point filters.
Vijayan, V; Panda, Rames C
2012-07-01
A PID controller is widely used to control industrial processes that are mostly open loop stable or unstable. Selection of proper feedback structure and controller tuning helps to improve the performance of the loop. In this paper a double-feedback loop/method is used to achieve stability and better performance of the process. The internal feedback is used for stabilizing the process and the outer loop is used for good setpoint tracking. An internal model controller (IMC) based PID method is used for tuning the outer loop controller. Autotuning based on relay feedback or the Ziegler-Nichols method can be used for tuning an inner loop controller. A tuning parameter (λ) that is used to tune IMC-PID is used as a time constant of a setpoint filter that is used for reducing the peak overshoot. The method has been tested successfully on many low order processes.
Automatic control systems for submerged membrane bioreactors: a state-of-the-art review.
Ferrero, Giuliana; Rodríguez-Roda, Ignasi; Comas, Joaquim
2012-07-01
Membrane bioreactor (MBR) technology has become relatively widespread as an advanced treatment for both industrial and municipal wastewater, especially in areas prone to water scarcity. Although operational cost is a key issue in MBRs, currently only a few crucial papers and inventions aimed to optimise and enhance MBR efficiency have been published. The present review summarises the available solutions in the area of automatic control systems and widely explores the advances in automation and control for MBRs. In this review of state of the art, different control systems are evaluated comparatively, distinguishing between control systems used for the filtration process and those used for the biological process of MBRs and describing the challenge faced by integrated control systems. The existing knowledge is classified according to the manipulated variables, the operational mode (open-loop or closed-loop) and the controlled variables used.
Lin, Yiing-Yuh; Lin, Gern-Liang
1992-08-01
In this research, the dynamics and control of a rigid spacecraft with flexible structures were studied for the case of optimal simultaneous multiaxis reorientation. A model spacecraft consisting of a rigid hub in the middle and two solid bodies symmetrically connected to either side of the hub through uniformly distributed flexible beams is considered for the dynamic analysis and control simulation. To optimally reorienting the spacecraft, an optimal nominal control trajectory is found first through an iterative procedure. Linear flexural deformations are assumed for the beam structures and the assumed modes method is applied to find the vibration control law of the beams. The system overall optimal attitude control is achieved by following the open loop optimal reference control trajectory with an stabilizing guidance law.
Efficiency of sediment transport by flood and its control in the Lower Yellow River
Institute of Scientific and Technical Information of China (English)
NI; Jinren; LIU; Xiaoyong; LI; Tianhong; ZHAO; Yean; JIN; L
2004-01-01
This paper presents the characteristics of sediment transport by flood in the Lower Yellow River with the reach from Huayuankou to Gaocun, which is regarded as a typical braided pattern. The Artificial Neural Network Model on Water Use for Sediment Transport (WUST) by flood was established based on the measured data from 1980 to 1998. Consequently, simulations of controlling process of sediment transport by flood were made in terms of the control theory under different scenarios. According to the situation of sediment transport by flood in the Lower Yellow River, Open-Loop control system and feedback control system were adopted in system design. In the Open-Loop control system, numerical simulations were made to reveal the relationship between average discharge of flood and the WUST with varying sediment concentrations. The results demonstrate that sediment concentration has significant influence on the controlling process of flood flow to WUST. It is practical and efficient to control WUST if sediment concentration is less than 20 kg/m3. In the feedback control system, controlling processes of sediment concentration and flood discharge for sediment transport were simulated respectively under given conditions, and it was found that sediment transport process could be controlled completely by sediment concentration and discharge at the inlet of the reach from Huayuankou to Gaocun. Using the same method, controlling processes of sediment transport by flood in other reaches in the Lower Yellow River were also simulated. For the case of sediment concentration being 20 kg/m3, the optimized controlling discharge ranges from 2390 to 2900 m3/s in the lower reach of Huayuankou.This study is also of significance to flood control and flushing sediment in the Lower Yellow River with proper operation modes of Xiaolangdi Reservoir.
Active vibration control based on piezoelectric smart composite
Gao, Le; Lu, Qingqing; Fei, Fan; Liu, Liwu; Liu, Yanju; Leng, Jinsong
2013-12-01
An aircraft’s vertical fin may experience dramatic buffet loads in high angle of attack flight conditions, and these buffet loads would cause huge vibration and dynamic stress on the vertical fin structure. To reduce the dynamic vibration of the vertical fin structure, macro fiber composite (MFC) actuators were used in this paper. The drive moment equations and sensing voltage equations of the MFC actuators were developed. Finite element analysis models based on three kinds of models of simplified vertical fin structures with surface-bonded MFC actuators were established in ABAQUS. The equivalent damping ratio of the structure was employed in finite element analysis, in order to measure the effectiveness of vibration control. Further, an open-loop test for the active vibration control system of the vertical fin with MFC actuators was designed and developed. The experimental results validated the effectiveness of the MFC actuators as well as the developed methodology.
Block-decoupling vibration control using eigenstructure assignment
Wei, Xiaojun; Mottershead, John E.
2016-06-01
A theoretical study is presented on the feasibility of applying active control for the purpose of vibration isolation in lightweight structures by block diagonalisation of the system matrices and at the same time assigning eigenvalues (natural frequencies and damping) to the chosen substructures separately. The methodology, based on eigenstructure assignment using the method of receptances, is found to work successfully when the eigenvalues of the open-loop system are controllable and the open- and closed-loop eigenvalues are distinct. In the first part of the paper results are obtained under the restriction that the mass matrix is diagonal (lumped). This is certainly applicable in the case of numerous engineering systems consisting of discrete masses with flexible interconnections of negligible mass. Later in the paper this restriction is lifted to allow bandedness of the mass matrix. Several numerical examples are used to illustrate the working of the proposed algorithm.
Integrated Process Design and Control of Reactive Distillation Processes
DEFF Research Database (Denmark)
Mansouri, Seyed Soheil; Sales-Cruz, Mauricio; Huusom, Jakob Kjøbsted
2015-01-01
In this work, integrated process design and control of reactive distillation processes is presented. Simple graphical design methods that are similar in concept to non-reactive distillation processes are used, such as reactive McCabe-Thiele method and driving force approach. The methods are based...... on the element concept, which is used to translate a system of compounds into elements. The operation of the reactive distillation column at the highest driving force and other candidate points is analyzed through analytical solution as well as rigorous open-loop and closed-loop simulations. By application...... of this approach, it is shown that designing the reactive distillation process at the maximum driving force results in an optimal design in terms of controllability and operability. It is verified that the reactive distillation design option is less sensitive to the disturbances in the feed at the highest driving...
A control theoretic model of driver steering behavior
Donges, E.
1977-01-01
A quantitative description of driver steering behavior such as a mathematical model is presented. The steering task is divided into two levels: (1) the guidance level involving the perception of the instantaneous and future course of the forcing function provided by the forward view of the road, and the response to it in an anticipatory open-loop control mode; (2) the stabilization level whereby any occuring deviations from the forcing function are compensated for in a closed-loop control mode. This concept of the duality of the driver's steering activity led to a newly developed two-level model of driver steering behavior. Its parameters are identified on the basis of data measured in driving simulator experiments. The parameter estimates of both levels of the model show significant dependence on the experimental situation which can be characterized by variables such as vehicle speed and desired path curvature.
Active Noise Control of Radiated Noise from Jets Originating NASA
Doty, Michael J.; Fuller, Christopher R.; Schiller, Noah H.; Turner, Travis L.
2013-01-01
The reduction of jet noise using a closed-loop active noise control system with highbandwidth active chevrons was investigated. The high frequency energy introduced by piezoelectrically-driven chevrons was demonstrated to achieve a broadband reduction of jet noise, presumably due to the suppression of large-scale turbulence. For a nozzle with one active chevron, benefits of up to 0.8 dB overall sound pressure level (OASPL) were observed compared to a static chevron nozzle near the maximum noise emission angle, and benefits of up to 1.9 dB OASPL were observed compared to a baseline nozzle with no chevrons. The closed-loop actuation system was able to effectively reduce noise at select frequencies by 1-3 dB. However, integrated OASPL did not indicate further reduction beyond the open-loop benefits, most likely due to the preliminary controller design, which was focused on narrowband performance.
Control and Virtual Reality Simulation of Tendon Driven Mechanisms
Energy Technology Data Exchange (ETDEWEB)
Londi, Fabio; Pennestri, Ettore, E-mail: pennestri@mec.uniroma2.it; Valentini, Pier Paolo; Vita, Leonardo [University of Tor Vergata, Department of Mechanical Engineering (Italy)
2004-09-15
In this paper the authors present a control strategy for tendon driven mechanisms. The aim of the control system is to find the correct torques which the motors have to exert to make the end effector describe a specific trajectory. In robotic assemblies this problem is often solved with closed loop algorithm, but here a simpler method, based on a open loop strategy, is developed. The difficulties in the actuation are in keeping the belt tight during all working conditions. So an innovative solution of this problem is presented here. This methodology can be easily applied in real time monitoring or very fast operations. For this reason several virtual reality simulations, developed using codes written in Virtual Reality Markup Language, are also presented. This approach is very efficient because it requires a very low cpu computation time, small size files, and the manipulator can be easily put into different simulated scenarios.
Fundamental Limits in Combine Harvester Header Height Control.
Xie, Yangmin; Alleyne, Andrew G; Greer, Ashley; Deneault, Dustin
2013-05-01
This paper investigates fundamental performance limitations in the control of a combine harvester's header height control system. There are two primary subsystem characteristics that influence the achievable bandwidth by affecting the open loop transfer function. The first subsystem is the mechanical configuration of the combine and header while the second subsystem is the electrohydraulic actuation for the header. The mechanical combine + header subsystem results in an input-output representation that is underactuated and has a noncollocated sensor/actuator pair. The electrohydraulic subsystem introduces a significant time delay. In combination, they each reinforce the effect of the other thereby exacerbating the overall system limitation of the closed loop bandwidth. Experimental results are provided to validate the model and existence of the closed loop bandwidth limitations that stem from specific system design configurations.
Simulation of closed loop controlled boost converter for solar installation
Directory of Open Access Journals (Sweden)
Kalirasu Athimulam
2010-01-01
Full Text Available With the shortage of the energy and ever increasing of the oil price, research on the renewable and green energy sources, especially the solar arrays and the fuel cells, becomes more and more important. How to achieve high stepup and high efficiency DC/DC converters is the major consideration in the renewable power applications due to the low voltage of PV arrays and fuel cells. In this paper digital simulation of closed loop controlled boost converter for solar installation is presented. Circuit models for open loop and closed loop controlled systems are developed using the blocks of simulink. The simulation results are compared with the theoretical results. This converter has advantages like improved power factor, fast response and reduced hardware. .
Directory of Open Access Journals (Sweden)
Keping Liu
2015-01-01
Full Text Available This paper presents a continuous control law of probe, which consists of PD (proportional-derivative controller and nonsingular terminal sliding mode controller for probe descending and landing phases, respectively, in the case of the asteroid irregular shape and low gravity. The probe dynamic model is deduced in the landing site coordinate system firstly. Then the reference trajectory based on optimal polynomial in open-loop state is designed, with the suboptimal fuel consumption. Taking into account different characteristics of phases, PD controller and nonsingular terminal sliding mode controller can be employed in the descending phase and the landing phase, respectively, to track the designed reference trajectory. The controller which used the corresponding control methods can meet the motion characteristics and requirements of each stage. Finally simulation experiments are carried out to demonstrate the effectiveness of the proposed method, which can ensure the safe landing of probe and achieve continuous control.
Application of infinite model predictive control methodology to other advanced controllers.
Abu-Ayyad, M; Dubay, R; Hernandez, J M
2009-01-01
This paper presents an application of most recent developed predictive control algorithm an infinite model predictive control (IMPC) to other advanced control schemes. The IMPC strategy was derived for systems with different degrees of nonlinearity on the process gain and time constant. Also, it was shown that IMPC structure uses nonlinear open-loop modeling which is conducted while closed-loop control is executed every sampling instant. The main objective of this work is to demonstrate that the methodology of IMPC can be applied to other advanced control strategies making the methodology generic. The IMPC strategy was implemented on several advanced controllers such as PI controller using Smith-Predictor, Dahlin controller, simplified predictive control (SPC), dynamic matrix control (DMC), and shifted dynamic matrix (m-DMC). Experimental work using these approaches combined with IMPC was conducted on both single-input-single-output (SISO) and multi-input-multi-output (MIMO) systems and compared with the original forms of these advanced controllers. Computer simulations were performed on nonlinear plants demonstrating that the IMPC strategy can be readily implemented on other advanced control schemes providing improved control performance. Practical work included real-time control applications on a DC motor, plastic injection molding machine and a MIMO three zone thermal system.
Lei, Jing; Jiang, Zuo; Li, Ya-Li; Li, Wu-Xin
2014-10-01
The problem of nonlinear vibration control for active vehicle suspension systems with actuator delay is considered. Through feedback linearization, the open-loop nonlinearity is eliminated by the feedback nonlinear term. Based on the finite spectrum assignment, the quarter-car suspension system with actuator delay is converted into an equivalent delay-free one. The nonlinear control includes a linear feedback term, a feedforward compensator, and a control memory term, which can be derived from a Riccati equation and a Sylvester equation, so that the effects produced by the road disturbances and the actuator delay are compensated, respectively. A predictor is designed to implement the predictive state in the designed control. Moreover, a reduced-order observer is constructed to solve its physical unrealisability problem. The stability proofs for the zero dynamics and the closed-loop system are provided. Numerical simulations illustrate the effectiveness and the simplicity of the designed control.
Modeling and control for a blended wing body aircraft a case study
Schirrer, Alexander
2015-01-01
This book demonstrates the potential of the blended wing body (BWB) concept for significant improvement in both fuel efficiency and noise reduction and addresses the considerable challenges raised for control engineers because of characteristics like open-loop instability, large flexible structure, and slow control surfaces. This text describes state-of-the-art and novel modeling and control design approaches for the BWB aircraft under consideration. The expert contributors demonstrate how exceptional robust control performance can be achieved despite such stringent design constraints as guaranteed handling qualities, reduced vibration, and the minimization of the aircraft’s structural loads during maneuvers and caused by turbulence. As a result, this innovative approach allows the building of even lighter aircraft structures, and thus results in considerable efficiency improvements per passenger kilometer. The treatment of this large, complex, parameter-dependent industrial control problem highlights relev...
Mu-Synthesis robust control of 3D bar structure vibration using piezo-stack actuators
Mystkowski, Arkadiusz; Koszewnik, Andrzej Piotr
2016-10-01
This paper presents an idea for the Mu-Synthesis robust control of 3D bar structure vibration with using a piezo-stack actuators. A model of the 3D bar structure with uncertain parameters is presented as multi-input multi-output (MIMO) dynamics. Nominal stability and nominal performances of the open-loop 3D bar structure dynamic model is developed. The uncertain model-based robust controller is derived due to voltage control signal saturation and selected parameter perturbations. The robust control performances and robustness of the system due to uncertainties influence is evaluated by using singular values and a small gain theorem. Finally, simulation investigations and experimental results shown that system response of the 3D bar structure dynamic model with taken into account perturbed parameters met desired robust stability and system limits. The proposed robust controller ensures a good dynamics of the closed-loop system, robustness, and vibration attenuation.
MODELING AND CONTROLLING OF PARALLEL MANIPULATOR JOINT DRIVEN BY PNEUMATIC MUSCLES
Institute of Scientific and Technical Information of China (English)
Tao Guoliang; Zhu Xiaocong; Cao Jian
2005-01-01
A parallel manipulator joint driven by three pneumatic muscles and its posture control strategy are presented. Based on geometric constraints and dynamics, a system model is developed through which some influences on dynamic response and open-loop gain are analyzed including the supply pressure, the initial pressure and the volume of pneumatic muscle. A sliding-mode controller with a nonlinear switching function is applied to control posture, which adopts the combination of a main method that separates control of each muscle and an auxiliary method that postures error evaluation of multiple muscles, especially adopting the segmented and intelligent adjustments of sliding-mode parameters to fit different expected postures and initial states. Experimental results show that this control strategy not only amounts to the steady-state error of O.1° without overshoot, but also achieves good trajectory tracking.
A review of control strategies in closed-loop neuroprosthetic systems
Directory of Open Access Journals (Sweden)
James Wright
2016-07-01
Full Text Available It has been widely recognized that closed-loop neuroprosthetic systems achieve more favorable outcomes for users then equivalent open-loop devices. Improved performance of tasks, better usability and greater embodiment have all been reported in systems utilizing some form of feedback. However the interdisciplinary work on neuroprosthetic systems can lead to miscommunication due to similarities in well established nomenclature in different fields. Here we present a review of control strategies in existing experimental, investigational and clinical neuroprosthetic systems in order to establish a baseline and promote a common understanding of different feedback modes and closed-loop controllers. The first section provides a brief discussion of feedback control and control theory. The second section reviews the control strategies of recent Brain Machine Interfaces, neuromodulatory implants, neuroprosthetic systems and assistive neurorobotic devices. The final section examines the different approaches to feedback in current neuroprosthetic and neurorobotic systems.
Deterministic Time-inconsistent Optimal Control Problems - an Essentially Cooperative Approach
Institute of Scientific and Technical Information of China (English)
Jiong-min YONG
2012-01-01
A general deterministic time-inconsistent optimal control problem is formulated for ordinary differential equations.To find a time-consistent equilibrium value function and the corresponding time-consistent equilibrium control,a non-cooperative N-person differential game (but essentially cooperative in some sense) is introduced.Under certain conditions,it is proved that the open-loop Nash equilibrium value function of the N-person differential game converges to a time-consistent equilibrium value function of the original problem,which is the value function of a time-consistent optimal control problem.Moreover,it is proved that any optimal control of the time-consistent limit problem is a time-consistent equilibrium control of the original problem.
Robust control of decoherence in realistic one-qubit quantum gates
Protopopescu, V; D'Helon, C; Schmulen, J
2003-01-01
We present an open-loop (bang-bang) scheme to control decoherence in a generic one-qubit quantum gate and implement it in a realistic simulation. The system is consistently described within the spin-boson model, with interactions accounting for both adiabatic and thermal decoherence. The external control is included from the beginning in the Hamiltonian as an independent interaction term. After tracing out the environment modes, reduced equations are obtained for the two-level system in which the effects of both decoherence and external control appear explicitly. The controls are determined exactly from the condition to eliminate decoherence, i.e. to restore unitarity. Numerical simulations show excellent performance and robustness of the proposed control scheme.
An Effective Approach Control Scheme for the Tethered Space Robot System
Directory of Open Access Journals (Sweden)
Zhongjie Meng
2014-09-01
Full Text Available The tethered space robot system (TSR, which is composed of a platform, a gripper and a space tether, has great potential in future space missions. Given the relative motion among the platform, tether, gripper and the target, an integrated approach model is derived. Then, a novel coordinated approach control scheme is presented, in which the tether tension, thrusters and the reaction wheel are all utilized. It contains the open-loop trajectory optimization, the feedback trajectory control and attitude control. The numerical simulation results show that the rendezvous between TSR and the target can be realized by the proposed coordinated control scheme, and the propellant consumption is efficiently reduced. Moreover, the control scheme performs well in the presence of the initial state’s perturbations, actuator characteristics and sensor errors.
Control assessment for heat integrated systems. An industrial case study for ethanol recovery
DEFF Research Database (Denmark)
Mauricio Iglesias, Miguel; Huusom, Jakob Kjøbsted; Sin, Gürkan
2013-01-01
. The assessment, both on open loop and closed loop, was carried out based on an industrial case study and compared to a modified case without heat integration. Although the heat integrated system displayed a certain deterioration of controllability, the control system made possible an efficient operation....... The reduction of energy consumption achieved thanks to heat integration was considerably larger than the losses due to poor control of the process, confirming the importance of heat integration in energy intensive processes.......Heat integration is essential for reducing the energy consumption of process industries. However, it may render the dynamic operation more interactive and difficult to control. This paper assesses the implications of heat integration in controllability and performance in energy reduction...
Directory of Open Access Journals (Sweden)
D. RAMA REDDY
2012-07-01
Full Text Available This paper describes the stability regions of PID (Proportional +Integral+ Derivative and a new PID with series leading correction (SLC for Networked control system with time delay. The new PID controller has a tuning parameter ‘β’. The relation between β, KP, KI and KD is derived. The effect of plant parameters on stabilityregion of PID controllers and SLC-PID controllers in first-order and second-order systems with time delay are also studied. Finally, an open-loop zero was inserted into the plant-unstable second order system with time delay so that the stability regions of PID and SLC-PID controllers get effectively enlarged. The total system isimplemented using MATLAB/Simulink.
Application of modern control design methodology to oblique wing research aircraft
Vincent, James H.
1991-01-01
A Linear Quadratic Regulator synthesis technique was used to design an explicit model following control system for the Oblique Wing Research Aircraft (OWRA). The forward path model (Maneuver Command Generator) was designed to incorporate the desired flying qualities and response decoupling. The LQR synthesis was based on the use of generalized controls, and it was structured to provide a proportional/integral error regulator with feedforward compensation. An unexpected consequence of this design approach was the ability to decouple the control synthesis into separate longitudinal and lateral directional designs. Longitudinal and lateral directional control laws were generated for each of the nine design flight conditions, and gain scheduling requirements were addressed. A fully coupled 6 degree of freedom open loop model of the OWRA along with the longitudinal and lateral directional control laws was used to assess the closed loop performance of the design. Evaluations were performed for each of the nine design flight conditions.
THE STUDY ON A KIND OF CONTROL SYSTEM WITH NONLINEAR PARABOLIC DISTRIBUTED PARAMETERS
Institute of Scientific and Technical Information of China (English)
周建军; 徐燕侯
2002-01-01
The modelling of one kind of nonlinear parabolic distributed parameter control system with moving boundary, which had extensive applications was presented. Two methods were used to investigate the basic characteristics of the system: 1 ) transforming the system in the variable domain into that in the fixed domain; 2) transforming the distributed parameter system into the lumped parameter system. It is found that there are two critical values for the control variable: the larger one determines whether or not the boundary would move, while the smaller one determines whether or not the boundary would stop automatically. For one-dimensional system of planar, cylindrical and spherical cases the definite solution problem can be expressed as a unified form. By means of the computer simulation the open-loop control system and close-cycle feedback control system have been investigated. Numerical results agree well with theoretical results. The computer simulation shows that the system is well posed, stable, measurable and controllable.
Combined input shaping and feedback control for double-pendulum systems
Mar, Robert; Goyal, Anurag; Nguyen, Vinh; Yang, Tianle; Singhose, William
2017-02-01
A control system combining input shaping and feedback is developed for double-pendulum systems subjected to external disturbances. The proposed control method achieves fast point-to-point response similar to open-loop input-shaping control. It also minimizes transient deflections during the motion of the system, and disturbance-induced residual swing using the feedback control. Effects of parameter variations such as the mass ratio of the double pendulum, the suspension length ratio, and the move distance were studied via numerical simulation. The most important results were also verified with experiments on a small-scale crane. The controller effectively suppresses the disturbances and is robust to modelling uncertainties and task variations.
High performance controller for drying processes - doi: 10.4025/actascitechnol.v35i2.14775
Directory of Open Access Journals (Sweden)
Camila Nicola Boeri
2013-04-01
Full Text Available This paper proposes a high performance nonlinear fuzzy multi-input-multi-output controller for a drying control process. The highly nonlinear characteristics of drying processes make classical control theory unable to provide the same performance results as it does in more well behaved systems. Advanced control strategies may be used to design temperature, relative humidity and air velocity nonlinear tracking controllers to overcome its highly non-linear dynamics over the whole drying operating conditions. Open-loop experiments were carried out to collect experienced-based knowledge of the process. PID and Fuzzy logic (FLC real-time-based controllers were designed to perform food drying tests and compared without controllers’ retuning. Absolute errors reached by FLC-based controller were 3.71 and 3.93 times lower than PID for temperature and relative humidity, respectively.
利用神经网络控制连续浇铸过程中的热传导%Control of Heat Transfer in Continuous Casting Process using Neural Networks
Institute of Scientific and Technical Information of China (English)
BOUHOUCHE Salah; LAHRECHE Malek; BAST Jürgen
2008-01-01
In continuous casting, the cooling-solidification process must be based on the adaptation of heat transfer, which is directly connected to casting conditions such as casting speed, casting temperature, and cooling parameters. Most control schemes are based on the static relation between casting speed and water flow rate in each cooling zone; this constitutes an open loop that does not consider the dynamic surface temperature, which is an important parameter for the final slab quality. In steelmaking, the casting-speed changes affect the global heat transfer. An optimal operation requires an adjustment of the process control variables, i.e., global heat transfer. A learning neural network (NN) allows the identification and the control of a nonlinear heat transfer model in the continuous casting process. A heat transfer model was developed using the dynamic heat balance. A comparison between the experimental open loop results and those of the model simulation is considered. Following adaptation, the model is used for controlling the slab surface temperature in closed loop, using NN technology and PID controllers. The NN identification and control strategy gives a stable temperature closed loop control comparatively to the conventional PID.
Institute of Scientific and Technical Information of China (English)
彭志萍
2015-01-01
A heliostat tracking control device and a heliostat tracking control method are proposed. The method adopts the open-loop and the closed-loop combined control, the open-loop roughly calculates and adjusts the position of a heliostat and the closed-loop corrects and eliminates the accumulated error till the precise tracking. The system adopts the combined control algorithm within the control period, thus achieving the precise tracking of the heliostat. The tracking reaction speed, the power consumption and the cost are low, thus forming a modular structure.%提出一种塔式太阳能热发电系统中定日镜跟踪控制装置及定日镜跟踪控制方法，采用开、闭环结合控制，开环粗略计算调整定日镜的位置，闭环校正，消除累积误差，直到精准跟踪。系统在控制周期内采用组合式控制算法，达到了定日镜的精准跟踪。跟踪反应速度，功耗和成本低，形成模块化结构。
Wang, Chenglei; Tang, Hui; Yu, Simon C. M.; Duan, Fei
2016-05-01
This paper studies the control of two-dimensional vortex-induced vibrations (VIVs) of a single circular cylinder at a Reynolds number of 100 using a novel windward-suction-leeward-blowing (WSLB) concept. A lattice Boltzmann method based numerical framework is adopted for this study. Both open-loop and closed-loop controls are implemented. In the open-loop control, three types of actuation arrangements, including the pure suction on the windward side of the cylinder, the pure blowing on the leeward side, and the general WSLB on both sides, are implemented and compared. It is found that the general WSLB is the most effective, whereas the pure suction is the least effective. In the closed-loop control, the proportional (P), integral (I), and proportional-integral (PI) control schemes are applied to adjust the WSLB velocities according to the flow information obtained from a sensor. The effects of four key control parameters including the proportional gain constant, the integral gain constant, the length of data history used for the feedback, and the location of the sensor are investigated. It is found that the use of only P control fails to completely suppress the VIV, the use of only I control can achieve the complete suppression, and the PI control performs the best in terms of both the control effectiveness and efficiency. In the PI control, there exists an optimal length of data history for the feedback, at which the VIV control is the most efficient. There also exist the minimum required WSLB velocities for the VIV suppression, independent of the control schemes. Moreover, it is found that the VIV control is independent of the sensor location.
Neuro-estimator based GMC control of a batch reactive distillation.
Prakash, K J Jithin; Patle, Dipesh S; Jana, Amiya K
2011-07-01
In this paper, an artificial neural network (ANN)-based nonlinear control algorithm is proposed for a simulated batch reactive distillation (RD) column. In the homogeneously catalyzed reactive process, an esterification reaction takes place for the production of ethyl acetate. The fundamental model has been derived incorporating the reaction term in the model structure of the nonreactive distillation process. The process operation is simulated at the startup phase under total reflux conditions. The open-loop process dynamics is also addressed running the batch process at the production phase under partial reflux conditions. In this study, a neuro-estimator based generic model controller (GMC), which consists of an ANN-based state predictor and the GMC law, has been synthesized. Finally, this proposed control law has been tested on the representative batch reactive distillation comparing with a gain-scheduled proportional integral (GSPI) controller and with its ideal performance (ideal GMC). Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.
Application handbook for a Standardized Control Module (SCM) for DC-DC converters, volume 1
Lee, F. C.; Mahmoud, M. F.; Yu, Y.
1980-01-01
The standardized control module (SCM) was developed for application in the buck, boost and buck/boost DC-DC converters. The SCM used multiple feedback loops to provide improved input line and output load regulation, stable feedback control system, good dynamic transient response and adaptive compensation of the control loop for changes in open loop gain and output filter time constraints. The necessary modeling and analysis tools to aid the design engineer in the application of the SCM to DC-DC Converters were developed. The SCM functional block diagram and the different analysis techniques were examined. The average time domain analysis technique was chosen as the basic analytical tool. The power stage transfer functions were developed for the buck, boost and buck/boost converters. The analog signal and digital signal processor transfer functions were developed for the three DC-DC Converter types using the constant on time, constant off time and constant frequency control laws.
A Complex Overview of Modeling and Control of the Rotary Single Inverted Pendulum System
Directory of Open Access Journals (Sweden)
Slavka Jadlovska
2013-01-01
Full Text Available The purpose of this paper is to present an in-depth survey of the rotary single inverted pendulum system from a control engineer's point of view. The scope of the survey includes modeling and open-loop analysis of the system as well as design and verification of balancing and swing up controllers which ensure successful stabilization of the pendulum in the unstable upright equilibrium. All relevant tasks and simulation experiments are conducted using the appropriate function blocks, GUI applications and demonstration schemes from a Simulink block library developed by the authors of the paper. The library is called Inverted Pendula Modeling and Control (IPMaC and offers comprehensive program support for modeling, simulation and control of classical (linear and rotary inverted pendulum systems.
Bernoulli substitution in the Ramsey model: Optimal trajectories under control constraints
Krasovskii, A. A.; Lebedev, P. D.; Tarasyev, A. M.
2017-05-01
We consider a neoclassical (economic) growth model. A nonlinear Ramsey equation, modeling capital dynamics, in the case of Cobb-Douglas production function is reduced to the linear differential equation via a Bernoulli substitution. This considerably facilitates the search for a solution to the optimal growth problem with logarithmic preferences. The study deals with solving the corresponding infinite horizon optimal control problem. We consider a vector field of the Hamiltonian system in the Pontryagin maximum principle, taking into account control constraints. We prove the existence of two alternative steady states, depending on the constraints. A proposed algorithm for constructing growth trajectories combines methods of open-loop control and closed-loop regulatory control. For some levels of constraints and initial conditions, a closed-form solution is obtained. We also demonstrate the impact of technological change on the economic equilibrium dynamics. Results are supported by computer calculations.
Active absorption of acoustic wave using state-space control approach
Wu, Zhen; Varadan, Vijay K.; Varadan, Vasundara V.; Lee, Kwang Y.
1994-05-01
This paper presents a computer modeling and simulation of an active sound absorbing system with an optimal state-feedback controller. First, a state-space model is developed to describe one-dimensional sound reflection and transmission in the time domain. In the model derivation, the difficulty of discretizing the wave equation in an unbounded region is overcome by combining the finite-difference and analytical solutions. Numerical simulation of the open- loop model response is performed, which shows a good agreement with the well known frequency domain solutions. Second, a state-feedback controller including a linear quadratic regulator and a Kalman filter type state-estimator is designed using the optimal control theory. Numerical simulation of the closed-loop model response of an active sound control system containing two sensors and one actuator is presented. It is shown that a broadband attenuation of more than 30 dB over 2 octaves has been reached.
Fractional order phase shaper design with Bode's integral for iso-damped control system.
Saha, Suman; Das, Saptarshi; Ghosh, Ratna; Goswami, Bhaswati; Balasubramanian, R; Chandra, A K; Das, Shantanu; Gupta, Amitava
2010-04-01
The phase curve of an open loop system is flat in nature if the derivative of its phase with respect to frequency is zero. With a flat-phase curve, the corresponding closed loop system exhibits an iso-damped property i.e. maintains constant overshoot with the change of gain. This implies enhanced parametric robustness e.g. to variation in system gain. In the recent past, fractional order (FO) phase shapers have been proposed by contemporary researchers to achieve enhanced parametric robustness. In this paper, a simple methodology is proposed to design an appropriate FO phase shaper to achieve phase flattening in a control loop, comprising a plant controlled by a classical Proportional Integral Derivative (PID) controller. The methodology is demonstrated with MATLAB simulation of representative plants and accompanying PID controllers.
Shaped Gaussian Dictionaries for Quantized Networked Control Systems With Correlated Dropouts
Peters, Edwin G. W.; Quevedo, Daniel E.; Ostergaard, Jan
2016-01-01
This paper studies fixed rate vector quantisation for noisy networked control systems (NCSs) with correlated packet dropouts. In particular, a discrete-time linear time invariant system is to be controlled over an error-prone digital channel. The controller uses (quantized) packetized predictive control to reduce the impact of packet losses. The proposed vector quantizer is based on sparse regression codes (SPARC), which have recently been shown to be efficient in open-loop systems when coding white Gaussian sources. The dictionaries in existing design of SPARCs consist of independent and identically distributed (i.i.d.) Gaussian entries. However, we show that a significant gain can be achieved by using Gaussian dictionaries that are shaped according to the second-order statistics of the NCS in question. Furthermore, to avoid training of the dictionaries, we provide closed-form expressions for the required second-order statistics in the absence of quantization.
Active vibration control using a modal-domain fiber optic sensor
Cox, David E.
1992-01-01
A closed-loop control experiment is described in which vibrations of a cantilevered beam are suppressed using measurements from a modal-domain fiber optic sensor. Modal-domain sensors are interference between the modes of a few-mode optical waveguide to detect strain. The fiber is bonded along the length of the beam and provides a measurement related to the strain distribution on the surface of the beam. A model for the fiber optic sensor is derived, and this model is integrated with the dynamic model of the beam. A piezoelectric actuator is also bonded to the beam and used to provide control forces. Control forces are obtained through dynamic compensation of the signal from the fiber optic sensor. The compensator is implemented with a real-time digital controller. Analytical models are verified by comparing simulations to experimental results for both open-loop and closed-loop configurations.
Active vibration control using a modal-domain fiber optic sensor
Cox, David E.
1992-01-01
A closed-loop control experiment is described in which vibrations of a cantilevered beam are suppressed using measurements from a modal-domain fiber optic sensor. Modal-domain sensors are interference between the modes of a few-mode optical waveguide to detect strain. The fiber is bonded along the length of the beam and provides a measurement related to the strain distribution on the surface of the beam. A model for the fiber optic sensor is derived, and this model is integrated with the dynamic model of the beam. A piezoelectric actuator is also bonded to the beam and used to provide control forces. Control forces are obtained through dynamic compensation of the signal from the fiber optic sensor. The compensator is implemented with a real-time digital controller. Analytical models are verified by comparing simulations to experimental results for both open-loop and closed-loop configurations.
Aerodynamic flow control of a high lift system with dual synthetic jet arrays
Alstrom, Robert Bruce
Implementing flow control systems will mitigate the vibration and aeroacoustic issues associated with weapons bays; enhance the performance of the latest generation aircraft by reducing their fuel consumption and improving their high angle-of-attack handling qualities; facilitate steep climb out profiles for military transport aircraft. Experimental research is performed on a NACA 0015 airfoil with a simple flap at angle of attack of 16o in both clean and high lift configurations. The results of the active control phase of the project will be discussed. Three different experiments were conducted; they are Amplitude Modulated Dual Location Open Loop Control, Adaptive Control with Amplitude Modulation using Direct Sensor Feedback and Adaptive Control with Amplitude Modulation using Extremum Seeking Control. All the closed loop experiments are dual location. The analysis presented uses the spatial variation of the root mean square pressure fluctuations, power spectral density estimates, Fast Fourier Transforms (FFTs), and time frequency analysis which consists of the application of the Morlet and Mexican Hat wavelets. Additionally, during the course of high speed testing in the wind tunnel, some aeroacoustic phenomena were uncovered; those results will also be presented. A cross section of the results shows that the shape of the RMS pressure distributions is sensitive to forcing frequency. The application of broadband excitation in the case adaptive control causes the flow to select a frequency to lock in to. Additionally, open loop control results in global synchronization via switching between two stable states and closed loop control inhibits the switching phenomena, but rather synchronizes the flow about multiple stable shedding frequencies.
CPG-based Locomotion Controller Design for a Boxfish-like Robot
Directory of Open Access Journals (Sweden)
Wei Wang
2014-06-01
Full Text Available This paper focuses on a Central Pattern Generator (CPG-based locomotion controller design for a boxfish-like robot. The bio-inspired controller is aimed at flexible switching in multiple 3D swimming patterns and exact attitude control of yaw and roll such that the robot will swim more like a real boxfish. The CPG network comprises two layers, the lower layer is the network of coupled linear oscillators and the upper is the transition layer where the lower-dimensional locomotion stimuli are transformed into the higher-dimensional control parameters serving for all the oscillators. Based on such a two-layer framework, flexible switching between multiple three-dimensional swimming patterns, such as swimming forwards/backwards, turning left/right, swimming upwards/downwards and rolling clockwise/counter-clockwise, can be simply realized by inputting different stimuli. Moreover, the stability of the CPG network is strictly proved to guarantee the intrinsic stability of the swimming patterns. As to exact attitude control, based on this open-loop CPG network and the sensory feedback from the Inertial Measurement Unit (IMU, a closed-loop CPG controller is advanced for yaw and roll control of the robotic fish for the first time. This CPG-based online attitude control for a robotic fish will greatly facilitate high-level practical underwater applications. A series of relevant experiments with the robotic fish are conducted systematically to validate the effectiveness and stability of the open-loop and closed-loop CPG controllers.
Operator in-the-loop control of rotary cranes
Energy Technology Data Exchange (ETDEWEB)
Parker, G.G.; Robinett, R.D.; Driessen, B.J.; Dohrmann, C.R.
1996-03-01
An open-loop control method is presented for reducing the oscillatory motion of rotary crane payloads during operator commanded maneuvers. A typical rotary crane consists of a multiple degree-of-freedom platform for positioning a spherical pendulum with an attached payload. The crane operator positions the Payload by issuing a combination of translational and rotational commands to the platform as well as load-line length changes. Frequently, these pendulum modes are time-varying and exhibit low natural frequencies. Maneuvers are therefore performed at rates sufficiently slow so as not to excite oscillation. The strategy presented here generates crane commands which suppress vibration of the payload without a priori knowledge of the desired maneuver. Results are presented for operator in-the-loop positioning using a real-time dynamics simulation of a three-axis rotary crane where the residual sway magnitude is reduced in excess of 4OdB.
Feedback-controlled laser fabrication of micromirror substrates.
Petrak, Benjamin; Konthasinghe, Kumarasiri; Perez, Sonia; Muller, Andreas
2011-12-01
Short (40-200 μs) single focused CO(2) laser pulses of energy ≳100 μJ were used to fabricate high quality concave micromirror templates on silica and fluoride glass. The ablated features have diameters of ≈20-100 μm and average root-mean-square (RMS) surface microroughness near their center of less than 0.2 nm. Temporally monitoring the fabrication process revealed that it proceeds on a time scale shorter than the laser pulse duration. We implement a fast feedback control loop (≈20 kHz bandwidth) based on the light emitted by the sample that ensures an RMS size dispersion of less than 5% in arrays on chips or in individually fabricated features on an optical fiber tip, a significant improvement over previous approaches using longer pulses and open loop operation.
Control system analysis for the perturbed linear accelerator rf system
Sung Il Kwon
2002-01-01
This paper addresses the modeling problem of the linear accelerator RF system in SNS. Klystrons are modeled as linear parameter varying systems. The effect of the high voltage power supply ripple on the klystron output voltage and the output phase is modeled as an additive disturbance. The cavity is modeled as a linear system and the beam current is modeled as the exogenous disturbance. The output uncertainty of the low level RF system which results from the uncertainties in the RF components and cabling is modeled as multiplicative uncertainty. Also, the feedback loop uncertainty and digital signal processing signal conditioning subsystem uncertainties are lumped together and are modeled as multiplicative uncertainty. Finally, the time delays in the loop are modeled as a lumped time delay. For the perturbed open loop system, the closed loop system performance, and stability are analyzed with the PI feedback controller.
Loram, Ian D; Gollee, Henrik; Lakie, Martin; Gawthrop, Peter J
2011-01-15
Human motor control is often explained in terms of engineering 'servo' theory. Recently, continuous, optimal control using internal models has emerged as a leading paradigm for voluntary movement. However, these engineering paradigms are designed for high band-width, inflexible, consistent systems whereas human control is low bandwidth and flexible using noisy sensors and actuators. By contrast, engineering intermittent control was designed for bandwidth-limited applications. Our general interest is whether intermittent rather than continuous control is generic to human motor control. Currently, it would be assumed that continuous control is the superior and physiologically natural choice for controlling unstable loads, for example as required for maintaining human balance. Using visuo-manual tracking of an unstable load, we show that control using gentle, intermittent taps is entirely natural and effective. The gentle tapping method resulted in slightly superior position control and velocity minimisation, a reduced feedback time delay, greater robustness to changing actuator gain and equal or greater linearity with respect to the external disturbance. Control was possible with a median contact rate of 0.8±0.3 s(-1). However, when optimising position or velocity regulation, a modal contact rate of 2 s(-1) was observed. This modal rate was consistent with insignificant disturbance-joystick coherence beyond 1-2 Hz in both tapping and continuous contact methods. For this load, these results demonstrate a motor control process of serial ballistic trajectories limited to an optimum rate of 2 s(-1). Consistent with theoretical reasoning, our results suggest that intermittent open loop action is a natural consequence of human physiology.
变转速泵控马达系统位置控制试验研究%Position Control Experimental Study in Variable-speed Pump-control-motor System
Institute of Scientific and Technical Information of China (English)
张磊; 彭天好; 钟日良; 乐南更
2014-01-01
对变转速泵控马达调速系统存在的位置跟踪效果不理想问题进行了研究，并针对马达角位移控制提出了闭环PID控制方法。基于虚拟仪器技术完成了位置控制测控系统的开发，将开发出的测控系统应用到变转速泵控马达调速系统上，完成了马达角位移的开环控制、闭环PID控制试验。试验结果表明，采用闭环PID控制时的马达角位移跟踪效果明显好于开环时的跟踪效果。%The problem of bad position tracking effect in governing system of variable-speed pump-control-motor was studied. And the closed-loop Proportional-Integration-Differential (PID)control method was proposed by aiming at the motor angular displace-ment control. The measurement and control system of position control based on virtual instrument technology (Labview)was devel-oped. The measurement and control system was applied to the governing system of variable-speed pump-control-motor. Then the related experiments of motor angular displacement control were carried out under open-loop control and closed-loop PID control. The result of experiments shows that the effect of closed-loop PID control of motor angular displacement is significantly better than that of open-loop control.
DEFF Research Database (Denmark)
Vidal, Ana; Yepes, Alejandro G.; Fernandez, Francisco Daniel Freijedo
2015-01-01
Rigorous analysis and design of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The loop behavior can be significantly influenced by the VSC working conditions. To consider such effect, converter losses should be included in the model, which can be done...... by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for the proper tuning of the current control loop. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller......, according to the internal model principle. The method gives a set of loss resistance values linked to working conditions, which can be used to improve the tuning of the current controllers, either by online adaptation of the controller gains or by open-loop adaptive adjustment of them according to prestored...
Aminov, Bachtior; Kolesov, Sergej; Pekeler, Michael; Piel, Christian; Piel, Helmut
2005-01-01
Since 2001 ACCEL Instruments is supplying low level RF control systems together with turn key cavity systems. The early LLRF systems used the well established technology based on discrete analogue amplitude and phase detectors and modulators. Today analogue LLRF systems can make use of advanced vector demodulators and modulators combined with a fast computer controlled analogue feed back loop. Feed forward control is implemented to operate the RF cavity in an open loop mode or to compensate for predictable perturbations. The paper will introduce the general design philosophy and show how it can be adapted to different tasks as controlling a synchrotron booster nc RF system at 500 MHz, or superconducting storage ring RF cavities, as well as a linear accelerator at 176 MHz formed by a chain of individually driven and controlled superconducting λ/2 cavities.
Das, Saptarshi; Pan, Indranil; Das, Shantanu
2015-09-01
An optimal trade-off design for fractional order (FO)-PID controller is proposed with a Linear Quadratic Regulator (LQR) based technique using two conflicting time domain objectives. A class of delayed FO systems with single non-integer order element, exhibiting both sluggish and oscillatory open loop responses, have been controlled here. The FO time delay processes are handled within a multi-objective optimization (MOO) formalism of LQR based FOPID design. A comparison is made between two contemporary approaches of stabilizing time-delay systems withinLQR. The MOO control design methodology yields the Pareto optimal trade-off solutions between the tracking performance and total variation (TV) of the control signal. Tuning rules are formed for the optimal LQR-FOPID controller parameters, using median of the non-dominated Pareto solutions to handle delayed FO processes.
Jin, Q B; Liu, Q; Huang, B
2016-03-01
This paper considers the problem of determining all the robust PID (proportional-integral-derivative) controllers in terms of the gain and phase margins (GPM) for open-loop unstable first order plus time delay (UFOPTD) processes. It is the first time that the feasible ranges of the GPM specifications provided by a PID controller are given for UFOPTD processes. A gain and phase margin tester is used to modify the original model, and the ranges of the margin specifications are derived such that the modified model can be stabilized by a stabilizing PID controller based on Hermite-Biehlers Theorem. Furthermore, we obtain all the controllers satisfying a given margin specification. Simulation studies show how to use the results to design a robust PID controller.
Closed and Open Loop Subspace System Identification of the Kalman Filter
Directory of Open Access Journals (Sweden)
David Di Ruscio
2009-04-01
Full Text Available Some methods for consistent closed loop subspace system identification presented in the literature are analyzed and compared to a recently published subspace algorithm for both open as well as for closed loop data, the DSR_e algorithm. Some new variants of this algorithm are presented and discussed. Simulation experiments are included in order to illustrate if the algorithms are variance efficient or not.
Open-loop tomography with artificial neural networks on CANARY: on-sky results
Osborn, J; Guzman, D; Basden, A; Morris, T J; Gendron, E; Butterley, T; Myers, R M; Gueslaga, A; Lasheras, F S; Victoria, M G; Rodriguez, M L S; Gratadour, D; Rousset, G
2014-01-01
We present recent results from the initial testing of an Artificial Neural Network (ANN) based tomographic reconstructor Complex Atmospheric Reconstructor based on Machine lEarNing (CARMEN) on Canary, an Adaptive Optics demonstrator operated on the 4.2m William Herschel Telescope, La Palma. The reconstructor was compared with contemporaneous data using the Learn and Apply (L&A) tomographic reconstructor. We find that the fully optimised L&A tomographic reconstructor outperforms CARMEN by approximately 5% in Strehl ratio or 15nm rms in wavefront error. We also present results for Canary in Ground Layer Adaptive Optics mode to show that the reconstructors are tomographic. The results are comparable and this small deficit is attributed to limitations in the training data used to build the ANN. Laboratory bench tests show that the ANN can out perform L&A under certain conditions, e.g. if the higher layer of a model two layer atmosphere was to change in altitude by ~300~m (equivalent to a shift of appr...
Compact and robust open-loop fiber-optic gyroscope for applications in harsh environments
Moslehi, Behzad M.; Yahalom, Ram; Faridian, Ferey; Black, Richard J.; Taylor, Edward W.; Ooi, Teng; Corder, Aaron
2010-09-01
Next generation navigation systems demand performance enhancements to support new applications with longer range capabilities, provide robust operation in severe thermal and vibration environments while simultaneously reducing weight, size and power dissipation. Compact, inexpensive, advanced guidance components are essential for such applications. In particular, Inertial Reference Units (IRUs) that can provide high-resolution stabilization and accurate inertial pointing knowledge are needed. For space applications, an added requirement is radiation hardening up to 300 krad over 5 to 15 years. Manufacturing specifications for the radiation-induced losses are not readily available and empirical test data is required for all components in order to optimize the system performance. Interferometric Fiber-Optic Gyroscopes (IFOGs) have proven to be a leading technology for tactical and navigational systems. The sensors have no moving parts. This ensures high reliability and a long life compared to the mechanical gyroscopes and dithered ring laser gyroscopes. However, the available architectures limit the potential size and cost of the IFOG. The work reported here describes an innovative approach for the design, fabrication, and testing of the IFOG and enables the production of a small, robust and low cost gyro with excellent noise and bandwidth characteristics with high radiation tolerance. The development is aimed at achieving a sensor volume architecture, where the light source, electronics and receiver are integrated in an external package, while the sensor head is integrated in a robust and environmentally rigid package. The sensor package design is compatible with the most severe environmental requirements foreseen for the target applications. This paper presents the current state-of-the-art performance of the prototype gyros and the potential for further reduction of size with improved performance. The gyro sample and data rates are extremely high and can be close to the modulation frequency (up to 80 kHz). IFOS has shown that the noise at high frequencies is not flattening out and extremely high bandwidth operation is possible without any degradation of the operational stability. IFOS has also demonstrated the potential for a future, smaller and extremely robust IFOG. The next phase design will include highly radiation-resistant integrated, compact optical circuits based on InP technology that includes the light source, splitter and receiver in one package, a gyro coil that utilizes small diameter, radiation-hard fiber and a small fiber phase modulator with > 300 krad radiation tolerance. This gyro offers the low noise, low drift, low vibration sensitivity, high accuracy, high bandwidth and high radiation tolerance solution required for next generation systems. We will present both theoretical modeling and experimental results obtained to date
Audu, Musa L; Odle, Brooke M; Triolo, Ronald J
2017-07-24
This study systematically explored the potential of applying feedback control of functional neuromuscular stimulation (FNS) for stabilizing various erect and leaning standing postures after spinal cord injury (SCI). Perturbations ranging from 2 to 6% body weight were applied to two subjects with motor complete thoracic level SCI who were proficient at standing with implanted multichannel neural stimulators to activate the ankle, knee, hip and trunk muscles. The subjects stood with four different postures: erect, forward, forward-right and forward-left. Repeatable and controlled perturbations were applied in the forward, backward, rightward and leftward directions by linear actuators pulling on ropes attached to the subjects via a belt worn just above the waist. Upper extremity (UE) forces exerted on a stationary walker were measured with load cells attached to the handles. A feedback controller based on center of pressure (CoP) varied the stimulation levels to the otherwise paralyzed muscles so as to resist the effects of the perturbations. The effect of the feedback controller was compared to the case where only open-loop baseline stimulation was applied. This was done in terms of: (a) maximum resultant UE force exerted by the subjects on the walker, (b) maximum resultant CoP overshoot and (c) CoP root-mean-square deviation (RMSD). Feedback control resulted in significant reductions in the mean values of the majority of outcome values compared to baseline open-loop stimulation. Maximum resultant UE force was reduced by as much as 50% in one of the postures for one of the subjects. RMSD and maximum CoPs were reduced by as much as 75 and 70%, respectively, with feedback control. These results indicate that feedback control can be used to reject destabilizing disturbances in individuals with SCI using FNS not only for erect postures but also for leaning postures typically adopted during reaching while attempting various activities of daily living.
Dynamics and control of spacecraft hovering using the geomagnetic Lorentz force
Huang, Xu; Yan, Ye; Zhou, Yang
2014-02-01
To achieve hovering, a spacecraft thrusts continuously to induce an equilibrium state at a desired position. Due to the constraints on the quantity of propellant onboard, long-time hovering around low-Earth orbits (LEO) is hardly achievable using traditional chemical propulsion. The Lorentz force, acting on an electrostatically charged spacecraft as it moves through a planetary magnetic field, provides a new propellantless method for orbital maneuvers. This paper investigates the feasibility of using the induced Lorentz force as an auxiliary means of propulsion for spacecraft hovering. Assuming that the Earth's magnetic field is a dipole that rotates with the Earth, a dynamical model that characterizes the relative motion of Lorentz spacecraft is derived to analyze the required open-loop control acceleration for hovering. Based on this dynamical model, we first present the hovering configurations that could achieve propellantless hovering and the corresponding required specific charge of a Lorentz spacecraft. For other configurations, optimal open-loop control laws that minimize the control energy consumption are designed. Likewise, the optimal trajectories of required specific charge and control acceleration are both presented. The effect of orbital inclination on the expenditure of control energy is also analyzed. Further, we also develop a closed-loop control approach for propellantless hovering. Numerical results prove the validity of proposed control methods for hovering and show that hovering around low-Earth orbits would be achievable if the required specific charge of a Lorentz spacecraft becomes feasible in the future. Typically, hovering radially several kilometers above a target in LEO requires specific charges on the order of 0.1 C/kg.
Depth Impact Control of an Electromagnetic Actuator for High Precision Engraving
Directory of Open Access Journals (Sweden)
E. Castillo–Castañeda
2008-10-01
Full Text Available This document presents both the mechanical elements and the motion control of a novel three–axis metal engraving machine. The aim of this work is to improve the conventional high resolution engraving techniques that commonly use expensive piezoelectric actuators with reduced impact depth. Also, it is presented the depth impact control in open loop for an electromagnetic actuator (solenoid. A conical tool is fixed on the mobile part of the solenoid that moves toward the work piece when the solenoid is energized. This novel machine performs micro–impacts of controlled depth on metallic flat surfaces and it can be also applied to high precision machining processes. The machine was experimentally tested on steel work pieces using scanned pictures.
Khandekar, A A; Malwatkar, G M; Patre, B M
2013-01-01
In this paper, a discrete time sliding mode controller (DSMC) is proposed for higher order plus delay time (HOPDT) processes. A sliding mode surface is selected as a function of system states and error and the tuning parameters of sliding mode controller are determined using dominant pole placement strategy. The condition for the existence of stable sliding mode is obtained by using Lyapunov function. The proposed method is applicable to HOPDT processes with oscillatory and integrating behavior, open loop instability or non-minimum phase characteristics and works satisfactory under the effect of parametric uncertainty. The method does not require reduced order model and provides simple way to design the controllers. The simulation and experimentation results show that the proposed method ensures desired tracking dynamics.
Design and simulation of a sensor for heliostat field closed loop control
Collins, Mike; Potter, Daniel; Burton, Alex
2017-06-01
Significant research has been completed in pursuit of capital cost reductions for heliostats [1],[2]. The camera array closed loop control concept has potential to radically alter the way heliostats are controlled and installed by replacing high quality open loop targeting systems with low quality targeting devices that rely on measurement of image position to remove tracking errors during operation. Although the system could be used for any heliostat size, the system significantly benefits small heliostats by reducing actuation costs, enabling large numbers of heliostats to be calibrated simultaneously, and enabling calibration of heliostats that produce low irradiance (similar or less than ambient light images) on Lambertian calibration targets, such as small heliostats that are far from the tower. A simulation method for the camera array has been designed and verified experimentally. The simulation tool demonstrates that closed loop calibration or control is possible using this device.
Faggian, Silvia
2007-01-01
The paper concerns the study of the Pontryagin Maximum Principle for an infinite dimensional and infinite horizon boundary control problem for linear partial differential equations. The optimal control model has already been studied both in finite and infinite horizon with Dynamic Programming methods in a series of papers by the same author, or by Faggian and Gozzi. Necessary and sufficient optimality conditions for open loop controls are established. Moreover the co-state variable is shown to coincide with the spatial gradient of the value function evaluated along the trajectory of the system, creating a parallel between Maximum Principle and Dynamic Programming. The abstract model applies, as recalled in one of the first sections, to optimal investment with vintage capital.
Modeling, simulation and identification for control of tandem cold metal rolling
Directory of Open Access Journals (Sweden)
Péricles Guedes Alves
2012-12-01
Full Text Available This paper describes a modeling procedure for tandem cold metal rolling, including the linearization step and system identification for control. The tandem cold rolling process is described by a mathematical model based on algebraic equations developed for control purposes and empirical relations. A state-space model is derived and detailed analyses in open loop are presented, concerning the sensitivity with regard to the variations in process parameters and results for the application of a new subspace identification method are compared with classical methodologies. Therefore, this work intents to be a contribution for developments in new control strategies for tandem cold rolling process that offer the potential to reduce the design efforts, the commissioning time and maintenance in rolling mills. The preliminary results obtained with this model have shown reasonable agreement with operational data presented at literature for industrial cold rolling process.
Dynamic Characteristic Analysis of Spinal Motor Control Between 11- and 15-Year-Old Children.
Chow, Daniel H; Lau, Newman M
2016-07-01
Spinal motor control can provide substantial insight for the causes of spinal musculoskeletal disorders. Its dynamic characteristics however, have not been fully investigated. The objective of this study is to explore the dynamic characteristics of spinal motor control via the fractional Brownian motion mathematical technique. Spinal curvatures and repositioning errors of different spinal regions in 64 children age 11- or 15-years old during upright stance were measured and compared for the effects of age and gender. With the application of the fractional Brownian motion analytical technique to the changes of spinal curvatures, distinct persistent movement behaviors could be determined, which could be interpreted physiologically as open-loop behaviors. Moreover, it was found that the spinal motor control of 15-year-old children was better than that of 11-year-old children with smaller repositioning error and less curvature variability as well as shorter response time and smaller curvature deformation.
Energy Technology Data Exchange (ETDEWEB)
Wolpert, Daniel; Gerber, Gustav; Brixner, Tobias [Physikalisches Institut, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Schade, Marco; Langhojer, Florian [Institut fuer Physikalische Chemie, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany)], E-mail: brixner@phys-chemie.uni-wuerzburg.de
2008-04-14
A shaped UV pump-MIR probe setup is employed for quantum control of the photoinduced Wolff rearrangement reaction of diazonaphthoquinone (DNQ) dissolved in methanol, yielding a ketene photoproduct. Time-resolved vibrational spectroscopy is a well-suited tool to monitor a photoreaction in the liquid phase as the narrow vibrational lines allow the observation of structural changes. Especially in the mid-infrared region, marker modes originating from different photoproducts can be identified unambiguously providing suitable feedback signals for open-loop or closed-loop control schemes. We report an experiment where the initiation of a complicated structural change of a molecule, involving bond cleavage and rearrangement, in the liquid phase can be controlled and mechanistic insight is obtained. Single-parameter scans show that the molecule is sensitive to intrapulse dumping during the excitation. Adaptive optimizations lead to pulse structures which can be understood consistently with this dumping mechanism.
A unified perspective on robot control - The energy Lyapunov function approach
Wen, John T.
1990-01-01
A unified framework for the stability analysis of robot tracking control is presented. By using an energy-motivated Lyapunov function candidate, the closed-loop stability is shown for a large family of control laws sharing a common structure of proportional and derivative feedback and a model-based feedforward. The feedforward can be zero, partial or complete linearized dynamics, partial or complete nonlinear dynamics, or linearized or nonlinear dynamics with parameter adaptation. As result, the dichotomous approaches to the robot control problem based on the open-loop linearization and nonlinear Lyapunov analysis are both included in this treatment. Furthermore, quantitative estimates of the trade-offs between different schemes in terms of the tracking performance, steady state error, domain of convergence, realtime computation load and required a prior model information are derived.
Hou, Gene; Koganti, Gopichand
1993-01-01
Controls-structure integrated design is a complicated multidisciplinary design optimization problem which involves the state equations pertaining to open-loop eigenvalues and control laws. In order to alleviate the intensity of the computation, this study uses the adjoint variable method to derive sensitivity equations for the eigenvalue, Liapunov, and Riccati equations. These individual sensitivity equations are then combined together to form the multidisciplinary sensitivity equations for the control structure integrated design problems. A set of linear sensitivity equations, proportional in number to the number of performance functions involved in the optimization process, are solved. This proposed approach may provide a great saving in computer resources. The validity of the newly developed sensitivity equations is verified by numerical examples.
Speed Control of DC Motor using AC/AC/DC Converter Based on Intelligent Techniques
Directory of Open Access Journals (Sweden)
Rakan Kh Antar
2013-05-01
Full Text Available This paper describes the application of ac/ac/dc and ac/dc converters to control the speed of a separately excited DC motor. Artificial neural network and PI controller are trained to select the desired values of firing angles for triggering thyristors of the ac/ac/dc and ac/dc bridge converters in order to control the speed of the dc motor at a desired value with constant and different load torques in order to obtain the best speed response. Simulation results show that the rising time for ac/dc and ac/ac/dc converters at 250rpm are reduced about 79% and 89% respectively, while delay time it reduced about 69% and 64% respectively. Therefore, speed response of the dc motor is more efficient for closed loop system compared with open loop also the response of ac/ac/dc converter is better than ac/dc converter.
On PID Controller Design by Combining Pole Placement Technique with Symmetrical Optimum Criterion
Directory of Open Access Journals (Sweden)
Viorel Nicolau
2013-01-01
Full Text Available In this paper, aspects of analytical design of PID controllers are studied, by combining pole placement technique with symmetrical optimum criterion. The proposed method is based on low-order plant model with pure integrator, and it can be used for both fast and slow processes. Starting from the desired closed-loop transfer function, which contains a second-order oscillating system and a lead-lag compensator, it is shown that the zero value depends on the real-pole value of closed-loop transfer function. In addition, there is only one pole value, which satisfies the assumptions of symmetrical optimum criterion imposed to open-loop transfer function. In these conditions, by combining the pole placement technique with symmetrical optimum criterion, the analytical expressions of the controller parameters can be simplified. For simulations, PID autopilot design for heading control problem of a conventional ship is considered.
Directory of Open Access Journals (Sweden)
Marcelo Dias Pedroso
2013-01-01
Full Text Available This work presents an adaptive control that integrates two linear control strategies applied to a step-down converter: Proportional Integral Derivative (PID and Linear Quadratic Regulator (LQR controls. Considering the converter open loop transfer function and using the poles placement technique, the designs of the two controllers are set so that the operating point of the closed loop system presents the same natural frequency. With poles placement design, the overshoot problems of the LQR controller are avoided. To achieve the best performance of each controller, a hyperbolic tangent weight function is applied. The limits of the hyperbolic tangent function are defined based on the system error range. Simulation results using the Altera DSP Builder software in a MATLAB/SIMULINK environment of the proposed control schemes are presented.
Cyclic modulation of semi-active controllable dampers for tonal vibration isolation
Anusonti-Inthra, P.; Gandhi, F.
2004-08-01
The present study examines the potential of using a semi-active controllable damper, whose damping coefficient can be modulated in real time, for tonal vibration isolation applications. A frequency-domain control algorithm is developed for determining the damping coefficient variation (at twice the disturbance frequency) that minimizes the force transmitted to the support at the disturbance frequency. The effectiveness of open-loop, closed-loop, and adaptive controllers in rejecting the transmitted disturbances are evaluated. The results of the study indicate that when limits in damping coefficient variation are considered, the support force could be reduced by about an additional 30%, beyond the levels due to the passive isolation characteristics (no cyclic damping modulation). When the disturbance phase changes during operation, the effectiveness of the open-loop controller is rapidly degraded. While the closed-loop controller (with inputs based on current levels of force transmitted to the support) performed better, there was still some degradation in performance, and transmitted support forces were not reduced to levels prior to the change in disturbance phase. The results show that for the semi-active system to retain its effectiveness in rejecting disturbances, a closed-loop, adaptive controller (with on-line system identification) is required; even when there is only a change in disturbance, and no change in basic system properties. An explanation for this phenomenon, related to the bi-linear nature of the semi-active system, is provided. Cyclic modulations in the damping coefficient were more effective in reducing the transmitted forces at the disturbance frequency than simply reducing the baseline damping coefficient (to improve the passive isolation characteristics).
DEFF Research Database (Denmark)
Sossan, Fabrizio; Bindner, Henrik W.
2012-01-01
control approach is convenient from communication point of view since the real-time data flow is only in one direction because the decision is computed locally according to user preferences. On the other hand, this approach results in an open loop control scheme, since it is assumed that no real-time...... power readings from the units can be performed. The aim of the paper is to discuss the performance of an emulated closed loop control using an estimator for predicting the aggregate power response and a regulator. By using these components it is possible to produce a control signal to broadcast...... to distributed demand side resources. A population of DSRs, buildings with electric space heating, is indeed simulated in a software simulation platform using an hardware in the loop approach, that allows to feedback the real heat dynamics of SYSLAB FlexHouse into the simulations for pretending more realistic...
Vanavil, B.; Krishna Chaitanya, K.; Seshagiri Rao, A.
2015-06-01
In this paper, a proportional-integral-derivative controller in series with a lead-lag filter is designed for control of the open-loop unstable processes with time delay based on direct synthesis method. Study of the performance of the designed controllers has been carried out on various unstable processes. Set-point weighting is considered to reduce the undesirable overshoot. The proposed scheme consists of only one tuning parameter, and systematic guidelines are provided for selection of the tuning parameter based on the peak value of the sensitivity function (Ms). Robustness analysis has been carried out based on sensitivity and complementary sensitivity functions. Nominal and robust control performances are achieved with the proposed method and improved closed-loop performances are obtained when compared to the recently reported methods in the literature.
DEFF Research Database (Denmark)
Mirzaei, Mahmood; Tibaldi, Carlo; Hansen, Morten Hartvig
2016-01-01
PI/PID controllers are the most common wind turbine controllers. Normally a first tuning is obtained using methods such as pole-placement or Ziegler-Nichols and then extensive aeroelastic simulations are used to obtain the best tuning in terms of regulation of the outputs and reduction of the loads....... In the traditional tuning approaches, the properties of different open loop and closed loop transfer functions of the system are not normally considered. In this paper, an assessment of the pole-placement tuning method is presented based on robustness measures. Then a constrained optimization setup is suggested...... to automatically tune the wind turbine controller subject to robustness constraints. The properties of the system such as the maximum sensitivity and complementary sensitivity functions (Ms and Mt), along with some of the responses of the system, are used to investigate the controller performance and formulate...
Stefanski, Frederik; Minorowicz, Bartosz; Persson, Johan; Plummer, Andrew; Bowen, Chris
2017-01-01
The potential to actuate proportional flow control valves using piezoelectric ceramics or other smart materials has been investigated for a number of years. Although performance advantages compared to electromagnetic actuation have been demonstrated, a major obstacle has proven to be ferroelectric hysteresis, which is typically 20% for a piezoelectric actuator. In this paper, a detailed study of valve control methods incorporating hysteresis compensation is made for the first time. Experimental results are obtained from a novel spool valve actuated by a multi-layer piezoelectric ring bender. A generalised Prandtl-Ishlinskii model, fitted to experimental training data from the prototype valve, is used to model hysteresis empirically. This form of model is analytically invertible and is used to compensate for hysteresis in the prototype valve both open loop, and in several configurations of closed loop real time control system. The closed loop control configurations use PID (Proportional Integral Derivative) control with either the inverse hysteresis model in the forward path or in a command feedforward path. Performance is compared to both open and closed loop control without hysteresis compensation via step and frequency response results. Results show a significant improvement in accuracy and dynamic performance using hysteresis compensation in open loop, but where valve position feedback is available for closed loop control the improvements are smaller, and so conventional PID control may well be sufficient. It is concluded that the ability to combine state-of-the-art multi-layer piezoelectric bending actuators with either sophisticated hysteresis compensation or closed loop control provides a route for the creation of a new generation of high performance piezoelectric valves.
Optimal performance of constrained control systems
Harvey, P. Scott, Jr.; Gavin, Henri P.; Scruggs, Jeffrey T.
2012-08-01
This paper presents a method to compute optimal open-loop trajectories for systems subject to state and control inequality constraints in which the cost function is quadratic and the state dynamics are linear. For the case in which inequality constraints are decentralized with respect to the controls, optimal Lagrange multipliers enforcing the inequality constraints may be found at any time through Pontryagin’s minimum principle. In so doing, the set of differential algebraic Euler-Lagrange equations is transformed into a nonlinear two-point boundary-value problem for states and costates whose solution meets the necessary conditions for optimality. The optimal performance of inequality constrained control systems is calculable, allowing for comparison to previous, sub-optimal solutions. The method is applied to the control of damping forces in a vibration isolation system subjected to constraints imposed by the physical implementation of a particular controllable damper. An outcome of this study is the best performance achievable given a particular objective, isolation system, and semi-active damper constraints.
Institute of Scientific and Technical Information of China (English)
Huaibin TANG; Zhen WU
2009-01-01
In this paper, the authors first study two kinds of stochastic differential equations (SDEs)cesses, the authors proceed to study a stochastic linear quadratic (LQ) optimal control problem with One kind of new stochastic Riccati equation that involves equality and inequality constraints is derived from the idea of square completion and its solvability is proved to be sufficient for the well-posedness and the existence of optimal control which can be of either state feedback or open-loop form of the LQ problems. Moreover, the authors obtain the existence and uniqueness of the solution to the Riccati equation for some special cases. Finally, two examples are presented to illustrate these theoretical results.
Performance Analysis of a Neuro-PID Controller Applied to a Robot Manipulator
Directory of Open Access Journals (Sweden)
Saeed Pezeshki
2012-11-01
Full Text Available The performance of robot manipulators with nonadaptive controllers might degrade significantly due to the open loop unstable system and the effect of some uncertainties on the robot model or environment. A novel Neural Network PID controller (NNP is proposed in order to improve the system performance and its robustness. The Neural Network (NN technique is applied to compensate for the effect of the uncertainties of the robot model. With the NN compensator introduced, the system errors and the NN weights with large dispersion are guaranteed to be bounded in the Lyapunov sense. The weights of the NN compensator are adaptively tuned. The simulation results show the effectiveness of the model validation approach and its efficiency to guarantee a stable and accurate trajectory tracking process in the presence of uncertainties.
On the Origins and Control of Community Types in the Human Microbiome.
Gibson, Travis E; Bashan, Amir; Cao, Hong-Tai; Weiss, Scott T; Liu, Yang-Yu
2016-02-01
Microbiome-based stratification of healthy individuals into compositional categories, referred to as "enterotypes" or "community types", holds promise for drastically improving personalized medicine. Despite this potential, the existence of community types and the degree of their distinctness have been highly debated. Here we adopted a dynamic systems approach and found that heterogeneity in the interspecific interactions or the presence of strongly interacting species is sufficient to explain community types, independent of the topology of the underlying ecological network. By controlling the presence or absence of these strongly interacting species we can steer the microbial ecosystem to any desired community type. This open-loop control strategy still holds even when the community types are not distinct but appear as dense regions within a continuous gradient. This finding can be used to develop viable therapeutic strategies for shifting the microbial composition to a healthy configuration.
Directory of Open Access Journals (Sweden)
Sajad Tabatabaee
2011-06-01
Full Text Available This paper presents a new approach to a robust fuzzy controller design for the bilateral teleportation system with varying time delays using linear matrix inequalities. Communication channels are considered with different forwarding and returning time delays. The time delays of communication channels are assumed to be unknown and randomly time varying, but the upper bounds of the delay interval and the derivative of the delay are assumed to be known. In order to design the controllers, first, an impedance controller is designed for the master system to achieve desired impedance behavior for the master. Then, nonlinear Euler-Lagrange equation of motion of the slave system is linearized in the neighborhood of some operating points. In the sequel, an open-loop scheme is considered for the slave system. The linear model of the slave system has two imaginary/unstable poles. The slave system is stabilized by a PD-controller to be used in the open-loop scheme. To design the slave controller, the tele-operator block diagram is rearranged such that the tele-operator block diagram converts to a standard representation of a feedback control system which helps us to design a robust H-infinity controller for the slave system. The local linear models of the system are combined to form a Takagi-Sugeno fuzzy model of the whole tele-operation system. A Lyapunov-Krasovskii function is defined to analyze the closed-loop system’s stability and derive a sufficient delay-dependent stability criterion. An H-infinity performance index is defined and the design criteria for the slave controller are expressed as a set of LMIs, which can be tested readily using standard numerical software.
Towards autonomous neuroprosthetic control using Hebbian reinforcement learning
Mahmoudi, Babak; Pohlmeyer, Eric A.; Prins, Noeline W.; Geng, Shijia; Sanchez, Justin C.
2013-12-01
Objective. Our goal was to design an adaptive neuroprosthetic controller that could learn the mapping from neural states to prosthetic actions and automatically adjust adaptation using only a binary evaluative feedback as a measure of desirability/undesirability of performance. Approach. Hebbian reinforcement learning (HRL) in a connectionist network was used for the design of the adaptive controller. The method combines the efficiency of supervised learning with the generality of reinforcement learning. The convergence properties of this approach were studied using both closed-loop control simulations and open-loop simulations that used primate neural data from robot-assisted reaching tasks. Main results. The HRL controller was able to perform classification and regression tasks using its episodic and sequential learning modes, respectively. In our experiments, the HRL controller quickly achieved convergence to an effective control policy, followed by robust performance. The controller also automatically stopped adapting the parameters after converging to a satisfactory control policy. Additionally, when the input neural vector was reorganized, the controller resumed adaptation to maintain performance. Significance. By estimating an evaluative feedback directly from the user, the HRL control algorithm may provide an efficient method for autonomous adaptation of neuroprosthetic systems. This method may enable the user to teach the controller the desired behavior using only a simple feedback signal.
Intelligent control based on intelligent characteristic model and its application
Institute of Scientific and Technical Information of China (English)
吴宏鑫; 王迎春; 邢琰
2003-01-01
This paper presents a new intelligent control method based on intelligent characteristic model for a kind of complicated plant with nonlinearities and uncertainties, whose controlled output variables cannot be measured on line continuously. The basic idea of this method is to utilize intelligent techniques to form the characteristic model of the controlled plant according to the principle of combining the char-acteristics of the plant with the control requirements, and then to present a new design method of intelli-gent controller based on this characteristic model. First, the modeling principles and expression of the intelligent characteristic model are presented. Then based on description of the intelligent characteristic model, the design principles and methods of the intelligent controller composed of several open-loops and closed-loops sub controllers with qualitative and quantitative information are given. Finally, the ap-plication of this method in alumina concentration control in the real aluminum electrolytic process is in-troduced. It is proved in practice that the above methods not only are easy to implement in engineering design but also avoid the trial-and-error of general intelligent controllers. It has taken better effect in the following application: achieving long-term stable control of low alumina concentration and increasing the controlled ratio of anode effect greatly from 60% to 80%.
Features of control systems analysis with discrete control devices using mathematical packages
Yakovleva, E. M.; Faerman, V. A.
2017-02-01
The article contains presentation of basic provisions of the theory of automatic pulse control systems as well as methods of analysis of such systems using the mathematical software widespread in the academic environment. The pulse systems under research are considered as analogues systems interacting among themselves, including sensors, amplifiers, controlled objects, and discrete parts. To describe such systems, one uses a mathematical apparatus of difference equations as well as discrete transfer functions. To obtain a transfer function of the open-loop system, being important from the point of view of the analysis of control systems, one uses mathematical packages Mathcad and Matlab. Despite identity of the obtained result, the way of its achievement from the point of view of user’s action is various for the specified means. In particular, Matlab uses a structural model of the control system while Mathcad allows only execution of a chain of operator transforms. It is worth noting that distinctions taking place allow considering transformation of signals during interaction of the linear and continuous parts of the control system from different sides. The latter can be used in an educational process for the best assimilation of the course of the control system theory by students.
Bio-Inspired Controller on an FPGA Applied to Closed-Loop Diaphragmatic Stimulation.
Zbrzeski, Adeline; Bornat, Yannick; Hillen, Brian; Siu, Ricardo; Abbas, James; Jung, Ranu; Renaud, Sylvie
2016-01-01
Cervical spinal cord injury can disrupt connections between the brain respiratory network and the respiratory muscles which can lead to partial or complete loss of ventilatory control and require ventilatory assistance. Unlike current open-loop technology, a closed-loop diaphragmatic pacing system could overcome the drawbacks of manual titration as well as respond to changing ventilation requirements. We present an original bio-inspired assistive technology for real-time ventilation assistance, implemented in a digital configurable Field Programmable Gate Array (FPGA). The bio-inspired controller, which is a spiking neural network (SNN) inspired by the medullary respiratory network, is as robust as a classic controller while having a flexible, low-power and low-cost hardware design. The system was simulated in MATLAB with FPGA-specific constraints and tested with a computational model of rat breathing; the model reproduced experimentally collected respiratory data in eupneic animals. The open-loop version of the bio-inspired controller was implemented on the FPGA. Electrical test bench characterizations confirmed the system functionality. Open and closed-loop paradigm simulations were simulated to test the FPGA system real-time behavior using the rat computational model. The closed-loop system monitors breathing and changes in respiratory demands to drive diaphragmatic stimulation. The simulated results inform future acute animal experiments and constitute the first step toward the development of a neuromorphic, adaptive, compact, low-power, implantable device. The bio-inspired hardware design optimizes the FPGA resource and time costs while harnessing the computational power of spike-based neuromorphic hardware. Its real-time feature makes it suitable for in vivo applications.
An integrated multivariable artificial pancreas control system.
Turksoy, Kamuran; Quinn, Lauretta T; Littlejohn, Elizabeth; Cinar, Ali
2014-05-01
The objective was to develop a closed-loop (CL) artificial pancreas (AP) control system that uses continuous measurements of glucose concentration and physiological variables, integrated with a hypoglycemia early alarm module to regulate glucose concentration and prevent hypoglycemia. Eleven open-loop (OL) and 9 CL experiments were performed. A multivariable adaptive artificial pancreas (MAAP) system was used for the first 6 CL experiments. An integrated multivariable adaptive artificial pancreas (IMAAP) system consisting of MAAP augmented with a hypoglycemia early alarm system was used during the last 3 CL experiments. Glucose values and physical activity information were measured and transferred to the controller every 10 minutes and insulin suggestions were entered to the pump manually. All experiments were designed to be close to real-life conditions. Severe hypoglycemic episodes were seen several times during the OL experiments. With the MAAP system, the occurrence of severe hypoglycemia was decreased significantly (P < .01). No hypoglycemia was seen with the IMAAP system. There was also a significant difference (P < .01) between OL and CL experiments with regard to percentage of glucose concentration (54% vs 58%) that remained within target range (70-180 mg/dl). Integration of an adaptive control and hypoglycemia early alarm system was able to keep glucose concentration values in target range in patients with type 1 diabetes. Postprandial hypoglycemia and exercise-induced hypoglycemia did not occur when this system was used. Physical activity information improved estimation of the blood glucose concentration and effectiveness of the control system.
Dual scheduling and quantised control for networked control systems with communication constraints
Lu, Hui; Zhou, Chuan
2016-07-01
A novel integrated design scheme of average dwell time scheduling strategy, dynamic bandwidth allocation policy and quantised control for a collection of networked control systems (NCSs) with time delay and communication constraints is proposed in this paper. A scheduling policy is presented to accommodate the limitation of communication capacity which depends on the convergence rate of closed-loop system and divergence rate of open-loop plant. Linear programming technique is adopted to dynamically allocate bit rate for each node and the strategy is used to make trade-offs between the network utilisation and the control performance which provides an effective way of optimising the quality of control (QoC) and the quality of service (QoS) for NCSs. Mid-tread uniform quantisers update the quantisation rules according to the assignment of the bit rate and convert the quantised state into a kind of input saturation with bounded disturbances. Taking into account the effect of dual scheduling strategy and quantisation, the NCSs are modelled as discrete-time switched systems with bounded disturbances. Furthermore, a scheduling and quantised feedback control co-design procedure is proposed for the simultaneous stabilisation of the collection of networked subsystems. Finally, a simulation example is given to illustrate the effectiveness of the proposed method.
Multiphase flow dynamics and control; Dynamique et controle des ecoulements polyphasiques
Energy Technology Data Exchange (ETDEWEB)
Duret, E.
2005-02-01
Production in the petroleum industry requires a better knowledge of multiphase flow, as the design of pipelines may cause the flow to become strongly unstable. For instance, for low flow rates and when a sea line ends at a riser, the riser base may accumulate liquid and stop the flow of gas. Then, the upstream gas is compressed until its pressure is large enough to push the liquid slug downstream. Under such conditions, a cyclic process occurs which is called severe slugging, generating large and fast fluctuations in pressure and flow rates. This thesis is devoted to two methods to stabilize this undesirable phenomenon. Using the pipeline's ability to separate phases to pick-up the gas upstream the riser base, they are mainly based on the perturbation theory (fast proportional effect, slow integral effect). The first one uses a secondary riser to transport the gas to the surface facilities. A stability study worked out with the phase diagrams technique shows that it is a good method to control this phenomenon. However, it imposes a high pressure in all the system. Thus, the second controller re-injects the gas at a determined height in the riser to decrease the hydrostatic pressure. A first stability study in open loop give a criterion on the minimal reinjection height. Then, the controller is developed by using the two-time scale control techniques. Finally, let us denote that these two controllers have been validated with a small size experimental set up. (author)
Load-following control of an IGCC plant with CO2 capture
Energy Technology Data Exchange (ETDEWEB)
Bhattacharyya, D.; Turton, R.; Zitney, S.
2011-01-01
In this paper, a decentralized control strategy is considered for load-following control of an integrated gasification combined cycle (IGCC) plant with CO2 capture without flaring the syngas. The control strategy considered is gas turbine (GT) lead with gasifier follow. In this strategy, the GT controls the power load by manipulating its firing rate while the slurry feed flow to the gasifier is manipulated to control the syngas pressure at the GT inlet. However, the syngas pressure control is an integrating process with significant timedelay. In this work, a modified proportional-integral-derivative (PID) control is considered for syngas pressure control given that conventional PID controllers show poor control performance for integrating processes with large time delays. The conventional PID control is augmented with an internal feedback loop. The P-controller used in this internal loop converts the integrating process to an open-loop stable process. The resulting secondorder plus time delay model uses a PID controller where the tuning parameters are found by minimizing the integral time-weighted absolute error (ITAE) for disturbance rejection. A plant model with single integrator and time delay is identified by a P-control method. When a ramp change is introduced in the set-point of the load controller, the performance of both the load and pressure controllers with the modified PID control strategy is found to be superior to that using a traditional PID controller. Key
Closed-loop response properties of a visual interneuron involved in fly optomotor control
Directory of Open Access Journals (Sweden)
Naveed eEjaz
2013-03-01
Full Text Available Due to methodological limitations neural function is mostly studied under open-loop conditions. Normally, however, nervous systems operate in closed-loop where sensory input is processed to generate behavioural outputs, which again change the sensory input. Here, we investigate the closed-loop responses of an identified visual interneuron, the blowfly H1-cell, that is part of a neural circuit involved in optomotor flight and gaze control. Those behaviours may be triggered by attitude changes during flight in turbulent air. The fly analyses the resulting retinal image shifts and performs compensatory body and head rotations to regain its default attitude. We developed a fly-robot interface to study H1-cell responses in a 1 degree-of-freedom image stabilization task. Image shifts, induced by externally forced rotations, modulate the cell’s spike rate that controls counter rotations of a mobile robot to minimize relative motion between the robot and its visual surroundings. A feedback controller closed the loop between neural activity and the rotation of the robot. Under these conditions we found the following H1-cell response properties: (i the peak spike rate decreases when the mean image velocity is increased, (ii the relationship between spike rate and image velocity depends on the standard deviation of the image velocities suggesting adaptive scaling of the cell’s signalling range, and (iii the cell’s gain decreases linearly with increasing image accelerations.Our results reveal a remarkable qualitative similarity between the response dynamics of the H1-cell under closed-loop conditions with those obtained in previous open-loop experiments. Finally, we show that the adaptive scaling of the H1-cell’s responses, while maximizing information on image velocity, decreases the cell’s sensitivity to image accelerations. Understanding such trade-offs in biological vision systems may advance the design of smart vision sensors for autonomous
Closed-loop response properties of a visual interneuron involved in fly optomotor control.
Ejaz, Naveed; Krapp, Holger G; Tanaka, Reiko J
2013-01-01
Due to methodological limitations neural function is mostly studied under open-loop conditions. Normally, however, nervous systems operate in closed-loop where sensory input is processed to generate behavioral outputs, which again change the sensory input. Here, we investigate the closed-loop responses of an identified visual interneuron, the blowfly H1-cell, that is part of a neural circuit involved in optomotor flight and gaze control. Those behaviors may be triggered by attitude changes during flight in turbulent air. The fly analyses the resulting retinal image shifts and performs compensatory body and head rotations to regain its default attitude. We developed a fly robot interface to study H1-cell responses in a 1 degree-of-freedom image stabilization task. Image shifts, induced by externally forced rotations, modulate the cell's spike rate that controls counter rotations of a mobile robot to minimize relative motion between the robot and its visual surroundings. A feedback controller closed the loop between neural activity and the rotation of the robot. Under these conditions we found the following H1-cell response properties: (i) the peak spike rate decreases when the mean image velocity is increased, (ii) the relationship between spike rate and image velocity depends on the standard deviation of the image velocities suggesting adaptive scaling of the cell's signaling range, and (iii) the cell's gain decreases linearly with increasing image accelerations. Our results reveal a remarkable qualitative similarity between the response dynamics of the H1-cell under closed-loop conditions with those obtained in previous open-loop experiments. Finally, we show that the adaptive scaling of the H1-cell's responses, while maximizing information on image velocity, decreases the cell's sensitivity to image accelerations. Understanding such trade-offs in biological vision systems may advance the design of smart vision sensors for autonomous robots.
Multichannel electrotactile feedback for simultaneous and proportional myoelectric control
Patel, Gauravkumar K.; Dosen, Strahinja; Castellini, Claudio; Farina, Dario
2016-10-01
Objective. Closing the loop in myoelectric prostheses by providing artificial somatosensory feedback to the user is an important need for prosthetic users. Previous studies investigated feedback strategies in combination with the control of one degree of freedom of simple grippers. Modern hands, however, are sophisticated multifunction systems. In this study, we assessed multichannel electrotactile feedback integrated with an advanced method for the simultaneous and proportional control of individual fingers of a dexterous hand. Approach. The feedback used spatial and frequency coding to provide information on the finger positions (normalized flexion angles). A comprehensive set of conditions have been investigated in 28 able-bodied subjects, including feedback modalities (visual, electrotactile and no feedback), control tasks (fingers and grasps), systems (virtual and real hand), control methods (ideal and realistic) and range of motion (low and high). The task for the subjects was to operate the hand using closed-loop myoelectric control and generate the desired movement (e.g., selected finger or grasp at a specific level of closure). Main results. The subjects could perceive the multichannel and multivariable electrotactile feedback and effectively exploit it to improve the control performance with respect to open-loop grasping. The improvement however depended on the reliability of the feedforward control, with less consistent control exhibiting performance trends that were more complex across the conditions. Significance. The results are promising for the potential application of advanced feedback to close the control loop in sophisticated prosthetic systems.
Humidity control tool for neonatal incubator.
Abdiche, M; Farges, G; Delanaud, S; Bach, V; Villon, P; Libert, J P
1998-03-01
In the first days of life, the daily evaporative loss from premature neonates can reach up to 20% of body mass. Such loss can be reduced by increasing the air humidity inside the incubator. Neither passive humidification nor open loop systems allow high humidity rates to be maintained or easily controlled: at 34 degrees C, the maximum levels vary with the system from 40% to 77% of relative humidity. The skin evaporative exchanges between the neonate and the environment are directly proportional to the water vapour partial pressure difference between the neonate's skin and the air. An active closed loop system has been designed, which permits reliable and accurate control of humidity according to the water vapour partial pressure set, between 1 and 6 kPa, in an air temperature range of 28-39 degrees C. It is characterised by variations of about 0.05 kPa around the set value and a maximum humidification speed of 0.25 kPa min-1. The algorithm is based on optimal control and the dynamic programming principles. Test results place this active system above usual systems for its power, precision and adaptability. It is an exploitable tool in fundamental and clinical research, to precisely study the humidity effects on neonatal comfort and thermo-regulation evolution.
Directory of Open Access Journals (Sweden)
T. H. S. Abdelaziz
2005-01-01
Full Text Available In this paper we introduce a complete parametric approach for solving the problem of eigenstructure assignment via state-derivative feedback for linear systems. This problem is always solvable for any controllable systems iff the open-loop system matrix is nonsingular. In this work, two parametric solutions to the feedback gain matrix are introduced that describe the available degrees of freedom offered by the state-derivative feedback in selecting the associated eigenvectors from an admissible class. These freedoms can be utilized to improve robustness of the closed-loop system. Accordingly, the sensitivity of the assigned eigenvalues to perturbations in the system and gain matrix is minimized. Numerical examples are included to show the effectiveness of the proposed approach.
Energy Technology Data Exchange (ETDEWEB)
Monteiro, Jose Roberto Boffino de Almeida
1997-07-01
The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)
Optimizing the performance of a VSC HVDC control system
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Mau Cuong; Rudion, Krzystof; Styczynski, Zbigniew Antoni [Magdeburg Univ. (Germany). Chair for Electric Power Networks and Renewable Energy Sources
2011-07-01
This paper deals with the optimization of the parameters in the various control loops of a voltage source converter based high voltage direct current (VSC HVDC) transmission system connected to a doubly fed induction generator (DFIG) based wind farm. These control loops include a number of proportional-integral (PI) controllers. The performance of VSC HVDC depends on the parameters of these PI controllers. In this paper, the control strategy of each converter of the VSC HVDC is first introduced to investigate a VSC HVDC transmission system that transfers DFIG wind power over a long distance. Secondly, the optimization process, based on the simplex method which is proposed in the literature, is applied with the initial values of the PI controller's parameters, which are obtained by studying the classical frequency response of the open-loop transfer function of the VSC HVDC. The objective is to simultaneously minimize the weighted sum of the integral of the time absolute-error products (ITAE) of the AC voltage, reactive power, DC voltage and inner current controllers of both VSC stations. The effectiveness of the optimized parameters is assessed in the field of requirements of the VSC HVDC control system as mentioned above during voltage down to zero to reduce the generated power from wind farm. (orig.)
Optimization Controller for Mechatronic Sun Tracking System to Improve Performance
Directory of Open Access Journals (Sweden)
Mustafa Engin
2013-01-01
Full Text Available An embedded system that contains hardware and software was developed for two-axis solar tracking system to improve photovoltaic panel utilization. The hardware section of the embedded system consists of a 32-bit ARM core microcontroller, motor driver circuits, a motion control unit, pyranometer, GPS receiver, and an anemometer. The real-time control algorithm enables the solar tracker to operate automatically without external control as a stand-alone system, combining the advantages of the open-loop and the closed-loop control methods. The pyranometer is employed to continuously send radiation data to the controller if the measured radiation is above the lower radiation limit the photovoltaic panel can generate power, guaranteeing the solar tracking process to be highly efficient. The anemometer is utilized in the system to ensure that the solar tracking procedure halts under high wind speed conditions to protect the entire system. Latitude, longitude, altitude, date, and real-time clock data are provided by GPS receiver. The algorithm calculates solar time using astronomical equations with GPS data and converts it to pulse-width modulated motor control signal. The overall objective of this study is to develop a control algorithm that improves performance and reliability of the two-axis solar tracker, focusing on optimization of the controller board, drive hardware, and software.
Directory of Open Access Journals (Sweden)
P. Karpagavalli
2013-01-01
Full Text Available This study presents the performance of a new four quadrant single phase DC drive closed loop system controlled by proportional integral and derivative controller with Pulse Width Modulation (PWM full bridge DC-DC converter using bipolar voltage switching. The proposed method is found to be more efficient in improving the step response characteristics such as reducing the settling time, rise time, steady state error and maximum overshoot in speed response of the closed loop DC motor drive and also reduced total harmonics distortion in the AC line current when compared to open loop system. The proposed topologies were simulated using MATLAB/Simulink software package and the results were obtained.
Directory of Open Access Journals (Sweden)
Y. Miladi
2013-10-01
Full Text Available In this paper we suggest a method to control the chaotic behavior of the stepper motor into a periodic one. In fact, using the supply frequency as a bifurcation parameter, we show that as the frequency is increased beyond a critical value the motor steps become irregular and even chaotic hence it becomes unpractical to be controlled in open loop mode. To circumvent the problem we propose a slight perturbation to the frequency in order to regularize the steps for high frequencies. The approach consists in using several heuristic methods such as Practical Swarm Optimization (PSO, Genetic Algorithms (GA and Ant Colony Optimization (ACO to obtain the optimal switching instances which define the change in the supply state (polarization. The numerical simulations performed on a stepper model show that regularization of the motor steps can be achieved for a large range of power supply frequencies ranging from quasiperiodic behavior to chaotic behavior.
Nonlinear Control Synthesis for Electrical Power Systems Using Controllable Series Capacitors
Manjarekar, N S
2012-01-01
In this work we derive asymptotically stabilizing control laws for electrical power systems using two nonlinear control synthesis techniques. For this transient stabilization problem the actuator considered is a power electronic device, a controllable series capacitor (CSC). The power system is described using two different nonlinear models - the second order swing equation and the third order flux-decay model. To start with, the CSC is modeled by the injection model which is based on the assumption that the CSC dynamics is very fast as compared to the dynamics of the power system and hence can be approximated by an algebraic equation. Here, by neglecting the CSC dynamics, the input vector $g(x)$ in the open loop system takes a complex form - the injection model. Using this model, interconnection and damping assignment passivity-based control (IDA-PBC) methodology is demonstrated on two power systems: a single machine infinite bus (SMIB) system and a two machine system. Further, IDA-PBC is used to derive stab...
Towards Quantum Cybernetics:. Optimal Feedback Control in Quantum Bio Informatics
Belavkin, V. P.
2009-02-01
A brief account of the quantum information dynamics and dynamical programming methods for the purpose of optimal control in quantum cybernetics with convex constraints and cońcave cost and bequest functions of the quantum state is given. Consideration is given to both open loop and feedback control schemes corresponding respectively to deterministic and stochastic semi-Markov dynamics of stable or unstable systems. For the quantum feedback control scheme with continuous observations we exploit the separation theorem of filtering and control aspects for quantum stochastic micro-dynamics of the total system. This allows to start with the Belavkin quantum filtering equation and derive the generalized Hamilton-Jacobi-Bellman equation using standard arguments of classical control theory. This is equivalent to a Hamilton-Jacobi equation with an extra linear dissipative term if the control is restricted to only Hamiltonian terms in the filtering equation. A controlled qubit is considered as an example throughout the development of the formalism. Finally, we discuss optimum observation strategies to obtain a pure quantum qubit state from a mixed one.
Speed Control of Induction Motor Using PLC and SCADA System
Directory of Open Access Journals (Sweden)
Ayman Seksak Elsaid,
2016-01-01
Full Text Available Automation or automatic control is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat-treating ovens, switching in telephone networks, steering and stabilization of ships, aircraft and other applications with minimal or reduced human intervention. Some processes have been completely automated. The motor speed is controlled via the driver as an open loop control. To make a more precise closed loop control of motor speed we will use a tachometer to measure the speed and feed it back to the PLC, which compares to the desired value and take a control action, then the signal is transferred to the motor – via driver – to increase / decrease the speed. We will measure the speed of the motor using an incremental rotary encoder by adjusting parameters (PLC, driver and also we need to reduce the overall cost of the system. Our control system will be held using the available Siemens PLC. In addition, we will monitor motor parameters via SCADA system.
Optimal Control of Airfoil Flow Separation using Fluidic Excitation
Shahrabi, Arireza F.
as well as F+ were evaluated and discussed. The computational model predictions showed good agreement with the experimental data. It was observed that different angles of attack and flap angles have different requirements for the minimum value of the momentum coefficient, Cμ, in order for the SJA to be effective for control of separation. It was also found that the variation of F + noticeably affects the lift and drag forces acting on the airfoil. The optimum values of parameters during open loop control simulations have been applied in order to introduce the optimal open loop control outcome. An innovative approach has been implemented to formulate optimal frequencies and momentum ratios of vortex shedding which depends on angle of attack and static pressure of the separation zone in the upper chord. Optimal open loop results have been compared with the optimal closed loop results. Cumulative case studies in the matter of angle of attacks, flap angles, Re, Cμ and F+ provide a convincing collection of evidence to the following conclusion. An improvement of a direct closed loop control was demonstrated, and an analytical formula describing the properties of a separated flow and vortex shedding was proposed. Best AFC solutions are offered by providing optimal frequencies and momentum ratios at a variety of flow conditions.
Selvaraj, Prashanth; Sleigh, Jamie W.; Kirsch, Heidi E.; Szeri, Andrew J.
2016-01-01
Optogenetics provides a method of neuron stimulation that has high spatial, temporal, and cell-type specificity. Here we present a model of optogenetic feedback control that targets the inhibitory population, which expresses light-sensitive channelrhodopsin-2 channels, in a mean-field model of undifferentiated cortex that is driven to seizures. The inhibitory population is illuminated with an intensity that is a function of electrode measurements obtained via the cortical model. We test the efficacy of this control method on seizurelike activity observed in two parameter spaces of the cortical model that most closely correspond to seizures observed in patients. We also compare the effect of closed-loop and open-loop control on seizurelike activity using a less-complicated ordinary differential equation model of the undifferentiated cortex in parameter space. Seizurelike activity is successfully suppressed in both parameter planes using optimal illumination intensities less likely to have adverse effects on cortical tissue.
Energy Technology Data Exchange (ETDEWEB)
Jacob, D. [Institut Universitaire de Technologie, 86 - Poitiers (France)
2004-09-15
The proportional integral derived function (PID) control is certainly not the most efficient but it is the most widely control used in regulation systems. The implementation of a PID regulator does not offer all adjustment possibilities of modern methods and it is in general impossible to make open-loop tests to identify the regulated system. This paper presents two concrete applications of PID control systems: one for a temperature regulation and the other for the servo-control of a mechanical system driven by a brush-less motor. The adjustment is performed using the classical momentum and frequency methods: 1 - PID control; 2 - efficiencies obtained in close loop configuration; 3 - principle of the experimental adjustment method of PID systems; 4 - experimental identification in close-loop configuration; 5 - calculation principle of a PID corrector; 6 - PID control for a class 0 system; 7 - calculation of a PID corrector for a class 1 system; 8 - PID position regulation of a brush-less motor; 9 - remarks about the numerical calculation of the control; 10 - summary of the models presented. (J.S.)
A nonlinear regression model-based predictive control algorithm.
Dubay, R; Abu-Ayyad, M; Hernandez, J M
2009-04-01
This paper presents a unique approach for designing a nonlinear regression model-based predictive controller (NRPC) for single-input-single-output (SISO) and multi-input-multi-output (MIMO) processes that are common in industrial applications. The innovation of this strategy is that the controller structure allows nonlinear open-loop modeling to be conducted while closed-loop control is executed every sampling instant. Consequently, the system matrix is regenerated every sampling instant using a continuous function providing a more accurate prediction of the plant. Computer simulations are carried out on nonlinear plants, demonstrating that the new approach is easily implemented and provides tight control. Also, the proposed algorithm is implemented on two real time SISO applications; a DC motor, a plastic injection molding machine and a nonlinear MIMO thermal system comprising three temperature zones to be controlled with interacting effects. The experimental closed-loop responses of the proposed algorithm were compared to a multi-model dynamic matrix controller (MPC) with improved results for various set point trajectories. Good disturbance rejection was attained, resulting in improved tracking of multi-set point profiles in comparison to multi-model MPC.
Quad-copter UAV BLDC Motor Control: Linear v/s non-linear control maps
Directory of Open Access Journals (Sweden)
Deep Parikh
2015-08-01
Full Text Available This paper presents some investigations and comparison of using linear versus non-linear static motor-control maps for the speed control of a BLDC (Brush Less Direct Current motors used in quad-copter UAV (Unmanned Aerial Vehicles. The motor-control map considered here is the inverse of the static map relating motor-speed output to motor-voltage input for a typical out-runner type Brushless DC Motors (BLDCM. Traditionally, quad-copter BLDC motor speed control uses simple linear motor-control map defined by the motor-constant specification. However, practical BLDC motors show non-linear characteristic, particularly when operated across wide operating speed-range as is commonly required in quad-copter UAV flight operations. In this paper, our investigations to compare performance of linear versus non-linear motor-control maps are presented. The investigations cover simulation-based and experimental study of BLDC motor speed control systems for quad-copter vehicle available. First the non-linear map relating rotor RPM to motor voltage for quad-copter BLDC motor is obtained experimentally using an optical speed encoder. The performance of the linear versus non-linear motor-control-maps for the speed control are studied. The investigations also cover study of time-responses for various standard test input-signals e.g. step, ramp and pulse inputs, applied as the reference speed-commands. Also, simple 2-degree of freedom test-bed is developed in our laboratory to help test the open-loop and closed-loop experimental investigations. The non-linear motor-control map is found to perform better in BLDC motor speed tracking control performance and thereby helping achieve better quad-copter roll-angle attitude control.
DEFF Research Database (Denmark)
Liu, Changjin; Chen, Wenjie; Blaabjerg, Frede
2012-01-01
This paper presents an analytical method to optimize the parameters of resonant controller which is used in a Doubly-Fed Induction Generator (DFIG). In the DFIG control system, the fundamental current loop is controlled by PI-controllers, and the stator harmonic current loop is controlled by reso...... design procedure of the resonant controller parameters is presented. The maximum possible gain of the resonant controller can be directly evaluated from the procedure. Simulations and experiments are presented to validate the complete analysis....... by resonant controllers. The effects of the resonant controller on the system stability and the steady-state performance are discussed in details. The analysis shows that the resonant controller has an important impact on the system stability when the resonant frequency is close to the crossover frequency...... of the open loop gain. The gain of the resonant controller is mainly determined by the DFIG transient inductance, the proportional gain of the PI controller, and the required phase margin. Based on the analytical expression of the phase margin and the crossover frequency of the control system, a systematic...
A Method for Precision Closed-Loop Irrigation Using a Modified PID Control Algorithm
Goodchild, Martin; Kühn, Karl; Jenkins, Malcolm; Burek, Kazimierz; Dutton, Andrew
2016-04-01
The benefits of closed-loop irrigation control have been demonstrated in grower trials which show the potential for improved crop yields and resource usage. Managing water use by controlling irrigation in response to soil moisture changes to meet crop water demands is a popular approach but requires knowledge of closed-loop control practice. In theory, to obtain precise closed-loop control of a system it is necessary to characterise every component in the control loop to derive the appropriate controller parameters, i.e. proportional, integral & derivative (PID) parameters in a classic PID controller. In practice this is often difficult to achieve. Empirical methods are employed to estimate the PID parameters by observing how the system performs under open-loop conditions. In this paper we present a modified PID controller, with a constrained integral function, that delivers excellent regulation of soil moisture by supplying the appropriate amount of water to meet the needs of the plant during the diurnal cycle. Furthermore, the modified PID controller responds quickly to changes in environmental conditions, including rainfall events which can result in: controller windup, under-watering and plant stress conditions. The experimental work successfully demonstrates the functionality of a constrained integral PID controller that delivers robust and precise irrigation control. Coir substrate strawberry growing trial data is also presented illustrating soil moisture control and the ability to match water deliver to solar radiation.
Yingping, Chen; Zhiqian, Li
2015-05-01
A 5.0-V 2.0-A flyback power supply controller providing constant-voltage (CV) and constant-current (CC) output regulation without the use of an optical coupler is presented. Dual-close-loop control is proposed here due to its better regulation performance of tolerance over process and temperature compared with open loop control used in common. At the same time, the two modes, CC and CV, could switch to each other automatically and smoothly according to the output voltage level not sacrificing the regulation accuracy at the switching phase, which overcomes the drawback of the digital control scheme depending on a hysteresis comparator to change the mode. On-chip compensation using active capacitor multiplier technique is applied to stabilize the voltage loop, eliminate an additional package pin, and save on the die area. The system consumes as little as 100 mW at no-load condition without degrading the transient response performance by utilizing the adaptive switching frequency control mode. The proposed controller has been implemented in a commercial 0.35-μm 40-V BCD process, and the active chip area is 1.5 × 1.0 mm2. The total error of the output voltage due to line and load variations is less than ±1.7%.
Flight control design using a blend of modern nonlinear adaptive and robust techniques
Yang, Xiaolong
In this dissertation, the modern control techniques of feedback linearization, mu synthesis, and neural network based adaptation are used to design novel control laws for two specific applications: F/A-18 flight control and reusable launch vehicle (an X-33 derivative) entry guidance. For both applications, the performance of the controllers is assessed. As a part of a NASA Dryden program to develop and flight test experimental controllers for an F/A-18 aircraft, a novel method of combining mu synthesis and feedback linearization is developed to design longitudinal and lateral-directional controllers. First of all, the open-loop and closed-loop dynamics of F/A-18 are investigated. The production F/A-18 controller as well as the control distribution mechanism are studied. The open-loop and closed-loop handling qualities of the F/A-18 are evaluated using low order transfer functions. Based on this information, a blend of robust mu synthesis and feedback linearization is used to design controllers for a low dynamic pressure envelope of flight conditions. For both the longitudinal and the lateral-directional axes, a robust linear controller is designed for a trim point in the center of the envelope. Then by including terms to cancel kinematic nonlinearities and variations in the aerodynamic forces and moments over the flight envelope, a complete nonlinear controller is developed. In addition, to compensate for the model uncertainty, linearization error and variations between operating points, neural network based adaptation is added to the designed longitudinal controller. The nonlinear simulations, robustness and handling qualities analysis indicate that the performance is similar to or better than that for the production F/A-18 controllers. When the dynamic pressure is very low, the performance of both the experimental and the production flight controllers is degraded, but Level I handling qualities are still achieved. A new generation of Reusable Launch Vehicles
CALL FOR PAPERS: Quantum control
Mancini, Stefano; Wiseman, Howard M.; Man'ko, Vladimir I.
2004-10-01
Over the last few decades, the achievements of highly precise technologies for manipulating systems at quantum scales have paved the way for the development of quantum control. Moreover, the proliferation of results in quantum information suggest that control theory might profitably be re-examined from this perspective. Journal of Optics B: Quantum and Semiclassical Optics will publish a topical issue devoted to quantum control. The Guest Editors invite contributions from researchers working in any area related to quantum control. Topics to be covered include: • Quantum Hamiltonian dynamics and programming control • Quantum decoherence control • Open loop control • Closed loop (feedback) control • Quantum measurement theory • Quantum noise and filtering • Estimation and decision theory • Quantum error correction • Group representation in quantum control • Coherent control in quantum optics and lasers • Coherent control in cavity QED and atom optics • Coherent control in molecular dynamics The topical issue is scheduled for publication in November 2005 and the DEADLINE for submission of contributions is 28 February 2005. All contributions will be peer-reviewed in accordance with the normal refereeing procedures and standards of Journal of Optics B: Quantum and Semiclassical Optics. Submissions should preferably be in either standard LaTeX form or Microsoft Word. Advice on publishing your work in the journal may be found at www.iop.org/journals/authors/jopb. Enquiries regarding this topical issue may be addressed to the Publisher, Dr Claire Bedrock (claire.bedrock@iop.org). There are no page charges for publication. The corresponding author of each paper published will receive a complimentary copy of the topical issue. Contributions to the topical issue should preferably be submitted electronically at www.iop.org/journals/authors/jopb or by e-mail to jopb@iop.org. Authors unable to submit online or by e-mail may send hard copy contributions
Aeroelastic scaling laws for gust load alleviation control system
Institute of Scientific and Technical Information of China (English)
Tang Bo; Wu Zhigang; Yang Chao
2016-01-01
Gust load alleviation (GLA) tests are widely conducted to study the effectiveness of the control laws and methods. The physical parameters of models in these tests are aeroelastic scaled, while the scaling of GLA control system is always unreached. This paper concentrates on studying the scaling laws of GLA control system. Through theoretical demonstration, the scaling criterion of a classical PID control system has been come up and a scaling methodology is provided and veri-fied. By adopting the scaling laws in this paper, gust response of the scaled model could be directly related to the full-scale aircraft theoretically under both open-loop and closed-loop conditions. Also, the influences of different scaling choices of an important non-dimensional parameter, the Froude number, have been studied in this paper. Furthermore for practical application, a compen-sating method is given when the theoretical scaled actuators or sensors cannot be obtained. Also, the scaling laws of some non-linear elements in control system such as the rate and amplitude sat-urations in actuator have been studied and examined by a numerical simulation.
Aeroelastic scaling laws for gust load alleviation control system
Directory of Open Access Journals (Sweden)
Tang Bo
2016-02-01
Full Text Available Gust load alleviation (GLA tests are widely conducted to study the effectiveness of the control laws and methods. The physical parameters of models in these tests are aeroelastic scaled, while the scaling of GLA control system is always unreached. This paper concentrates on studying the scaling laws of GLA control system. Through theoretical demonstration, the scaling criterion of a classical PID control system has been come up and a scaling methodology is provided and verified. By adopting the scaling laws in this paper, gust response of the scaled model could be directly related to the full-scale aircraft theoretically under both open-loop and closed-loop conditions. Also, the influences of different scaling choices of an important non-dimensional parameter, the Froude number, have been studied in this paper. Furthermore for practical application, a compensating method is given when the theoretical scaled actuators or sensors cannot be obtained. Also, the scaling laws of some non-linear elements in control system such as the rate and amplitude saturations in actuator have been studied and examined by a numerical simulation.
转子磁链定向的矢量控制系统的研究%Study of Rotor Flux Oriented Vector Control System
Institute of Scientific and Technical Information of China (English)
晏永红
2011-01-01
利用计算机仿真技术simulink对直接矢量控制系统进行分析研究,仿真结果表明按转子磁链定向的矢量控制系统克服了磁链开环系统的缺点,提高了系统的动态性能,这种系统具有广泛的实用价值.%Using computer simulation simulink for direct vector control system analysis, simulation results show that the rotor flux-oriented vector control system overcomes the flux disadvantage of open-loop system, improves the system dynamic performance, this system has a wide range of practical value.
Ekkachai, Kittipong; Nilkhamhang, Itthisek
2016-11-01
In recent years, intelligent prosthetic knees have been developed that enable amputees to walk as normally as possible when compared to healthy subjects. Although semi-active prosthetic knees utilizing magnetorheological (MR) dampers offer several advantages, they lack the ability to generate active force that is required during some states of a normal gait cycle. This prevents semi-active knees from achieving the same level of performance as active devices. In this work, a new control algorithm for a semi-active prosthetic knee during the swing phase is proposed to reduce this gap. The controller uses neural network predictive control and particle swarm optimization to calculate suitable command signals. Simulation results using a double pendulum model show that the generated knee trajectory of the proposed controller is more similar to the normal gait than previous open-loop controllers at various ambulation speeds. Moreover, the investigation shows that the algorithm can be calculated in real time by an embedded system, allowing for easy implementation on real prosthetic knees.
Dynamics and Predictive Control of Gas Phase Propylene Polymerization in Fluidized Bed Reactors
Institute of Scientific and Technical Information of China (English)
Ahmad Shamiri; Mohamed azlan Hussain; Farouq sabri Mjalli; Navid Mostoufi; Seyedahmad Hajimolana
2013-01-01
A two-phase dynamic model, describing gas phase propylene polymerization in a fluidized bed reactor, was used to explore the dynamic behavior and process control of the polypropylene production rate and reactor temperature. The open loop analysis revealed the nonlinear behavior of the polypropylene fluidized bed reactor, jus-tifying the use of an advanced control algorithm for efficient control of the process variables. In this case, a central-ized model predictive control (MPC) technique was implemented to control the polypropylene production rate and reactor temperature by manipulating the catalyst feed rate and cooling water flow rate respectively. The corre-sponding MPC controller was able to track changes in the setpoint smoothly for the reactor temperature and pro-duction rate while the setpoint tracking of the conventional proportional-integral (PI) controller was oscillatory with overshoots and obvious interaction between the reactor temperature and production rate loops. The MPC was able to produce controller moves which not only were well within the specified input constraints for both control vari-ables, but also non-aggressive and sufficiently smooth for practical implementations. Furthermore, the closed loop dynamic simulations indicated that the speed of rejecting the process disturbances for the MPC controller were also acceptable for both controlled variables.
Precision Attitude Control for the BETTII Balloon-Borne Interferometer
Benford, Dominic J.; Fixsen, Dale J.; Rinehart. Stephen
2012-01-01
The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII) is an 8-meter baseline far-infrared interferometer to fly on a high altitude balloon. Operating at wavelengths of 30-90 microns, BETTII will obtain spatial and spectral information on science targets at angular resolutions down to less than half an arcsecond, a capability unmatched by other far-infrared facilities. This requires attitude control at a level ofless than a tenth of an arcsecond, a great challenge for a lightweight balloon-borne system. We have designed a precision attitude determination system to provide gondola attitude knowledge at a level of 2 milliarcseconds at rates up to 100Hz, with accurate absolute attitude determination at the half arcsecond level at rates of up to 10Hz. A mUlti-stage control system involving rigid body motion and tip-tilt-piston correction provides precision pointing stability to the level required for the far-infrared instrument to perform its spatial/spectral interferometry in an open-loop control. We present key aspects of the design of the attitude determination and control and its development status.
Simulation of process identification and controller tuning for flow control system
Chew, I. M.; Wong, F.; Bono, A.; Wong, K. I.
2017-06-01
PID controller is undeniably the most popular method used in controlling various industrial processes. The feature to tune the three elements in PID has allowed the controller to deal with specific needs of the industrial processes. This paper discusses the three elements of control actions and improving robustness of controllers through combination of these control actions in various forms. A plant model is simulated using the Process Control Simulator in order to evaluate the controller performance. At first, the open loop response of the plant is studied by applying a step input to the plant and collecting the output data from the plant. Then, FOPDT of physical model is formed by using both Matlab-Simulink and PRC method. Then, calculation of controller’s setting is performed to find the values of Kc and τi that will give satisfactory control in closed loop system. Then, the performance analysis of closed loop system is obtained by set point tracking analysis and disturbance rejection performance. To optimize the overall physical system performance, a refined tuning of PID or detuning is further conducted to ensure a consistent resultant output of closed loop system reaction to the set point changes and disturbances to the physical model. As a result, the PB = 100 (%) and τi = 2.0 (s) is preferably chosen for setpoint tracking while PB = 100 (%) and τi = 2.5 (s) is selected for rejecting the imposed disturbance to the model. In a nutshell, selecting correlation tuning values is likewise depended on the required control’s objective for the stability performance of overall physical model.
The Sensorless Control of Brushless DC Fan Motors Based on Current Feedback%基于电流反馈的直流无刷风扇电机无传感器控制
Institute of Scientific and Technical Information of China (English)
苏译; 徐晓昂
2012-01-01
针对无传感器直流无刷风扇电机开环控制的不稳定性和转速闭环控制的相位偏差,首先从直流无刷风扇电机的数学模型及反电势过零点检测方法出发,阐述了由外部PWM驱动的开环控制和转速闭环控制方法的不足,提出了一种新型的基于电流反馈的无传感器直流无刷风扇电机控制系统.最后借助MATLAB/Simulink软件进行了建模与仿真,验证了新型控制系统的可行性.仿真结果表明,提出的控制系统具有良好的稳定性并有效消除了相位偏差.%For instability of open-loop control and phase deviation of speed closed-loop control in sensorless brushless DC fan motors, this paper begins with the mathematical model and the detection method of zero crossing point of brushless DC fan motors, the defects existing in the open-loop control driven by external PWM signals and closed-loop speed control method are expounded, a novel control system of sensorless brushless DC fan motors based on the current feedback is proposed. Finally, the software of MATLAB is used for the modeling and simulation for the whole system, the feasibility of the proposed control system is verified. The simulation results show that the proposed control system has a good stability and eliminates the phase offset effectively.
Institute of Scientific and Technical Information of China (English)
孟光伟; 李槐树
2011-01-01
提出了具有SVPWM控制和电流调节控制的无位置传感器双绕组无刷直流电机(BLDCM)的起动控制,其中电流调节控制采用两点式比较器控制.该起动控制方法不但能有效控制起动电流大小,而且能改善BLDCM开环起动性能.在Matlab/Simulink环境下.建立双绕组永磁BLDCM起动控制系统的仿真模型.设计了基于DSP2407A的双绕组BLDCM控制电路.并通过软件编程的方式实现了SVPWM的开环起动控制.仿真和实验结果一致.且结果表明了理论分析的正确性.%A startup control strategy with SVPWM and current regulation is proposed for the sensorless permanent magnet BLDCM(BrushLess DC Motor) with dual windings. Two-point comparator is used in its current regulation control. It controls the startup current efficiently and improves the open-loop startup performance of BLDCM. The simulation model of startup control system for permanent magnet BLDCM with dual windings is built with Matlab/Simulink software,the control circuit of BLDCM is designed based on DSP2407A chip,and the open-loop control is programmed for SVPWM. The simulative results are consistent with the experimental results,which show the correctness of the proposed control strategy.
Directory of Open Access Journals (Sweden)
Sniders A.
2016-06-01
Full Text Available The paper considers a survey of the research procedures and results due to invariant control method application perspective for operation quality advancement in several technological plants (wastewater biological treatment tanks and water steam production boilers, which operate under influence of organised and random disturbances. A specified subject of research is the simulation model of the multi-link invariant control system for steam pressure stabilisation in a steam boiler by preemptive compensation of steam load and feed water flow impact on output parameter (steam pressure, developed in MATLAB/SIMULINK. Simulation block-diagram of the steam boiler invariant control system, containing closed loop PID control circuit and open loop DPC circuit, has been composed on the basis of the designed mathematical model of the system components, disturbance compensation algorithms, and operational equation of the invariant control system. Comparative response of the steam boiler, operating under influence of fluctuating disturbances, with conventional PID control and using PID-DPC control with disturbance compensation controller DPC, has been investigated. Simulation results of invariant PID – DPC control system show that output parameter of the steam boiler - pressure remains practically constant under fluctuating disturbances due to a high-speed response of DPC controller.
Sniders, A.; Laizans, A.; Komass, T.
2016-06-01
The paper considers a survey of the research procedures and results due to invariant control method application perspective for operation quality advancement in several technological plants (wastewater biological treatment tanks and water steam production boilers), which operate under influence of organised and random disturbances. A specified subject of research is the simulation model of the multi-link invariant control system for steam pressure stabilisation in a steam boiler by preemptive compensation of steam load and feed water flow impact on output parameter (steam pressure), developed in MATLAB/SIMULINK. Simulation block-diagram of the steam boiler invariant control system, containing closed loop PID control circuit and open loop DPC circuit, has been composed on the basis of the designed mathematical model of the system components, disturbance compensation algorithms, and operational equation of the invariant control system. Comparative response of the steam boiler, operating under influence of fluctuating disturbances, with conventional PID control and using PID-DPC control with disturbance compensation controller DPC, has been investigated. Simulation results of invariant PID - DPC control system show that output parameter of the steam boiler - pressure remains practically constant under fluctuating disturbances due to a high-speed response of DPC controller.
Nonlinear model identification and adaptive model predictive control using neural networks.
Akpan, Vincent A; Hassapis, George D
2011-04-01
This paper presents two new adaptive model predictive control algorithms, both consisting of an on-line process identification part and a predictive control part. Both parts are executed at each sampling instant. The predictive control part of the first algorithm is the Nonlinear Model Predictive Control strategy and the control part of the second algorithm is the Generalized Predictive Control strategy. In the identification parts of both algorithms the process model is approximated by a series-parallel neural network structure which is trained by a recursive least squares (ARLS) method. The two control algorithms have been applied to: 1) the temperature control of a fluidized bed furnace reactor (FBFR) of a pilot plant and 2) the auto-pilot control of an F-16 aircraft. The training and validation data of the neural network are obtained from the open-loop simulation of the FBFR and the nonlinear F-16 aircraft models. The identification and control simulation results show that the first algorithm outperforms the second one at the expense of extra computation time.
Zambrano, J A; Gil-Martinez, M; Garcia-Sanz, M; Irizar, I
2009-01-01
Autothermal Thermophilic Aerobic Digestion (ATAD technology) is a promising alternative to conventional digestion systems. Aeration is a key factor in the performance of these kinds of reactors, in relation to effluent quality and operating costs. At present, the realisation of automatic control in ATADs is in its infancy. Additionally, the lack of robust sensors also makes the control of these processes difficult: only redox potential and temperature sensors are reliable for operation in full-scale plants. Based as it is on the existing simulation protocols for benchmarking of control strategies for wastewater treatment plants (WWTP), this paper presents the definition and implementation of a similar protocol but specifically adapted to the needs of ATAD technology. The implemented simulation protocol has been used to validate two different control strategies for aeration (ST1 and ST2). In comparison to an open-loop operation for the ATAD, simulation results showed that the ST1 strategy was able to save aeration costs of around 2-4%. Unlike ST1, ST2 achieved maximum sludge stabilisation but at the expense of higher aeration costs.
Nonlinear control synthesis for electrical power systems using controllable series capacitors
Energy Technology Data Exchange (ETDEWEB)
Manjarekar, N.S.; Banavar, Ravi N. [Indian Institute of Technology Bombay, Mumbai (India). Systems and Control Engineering
2012-07-01
In this work we derive asymptotically stabilizing control laws for electrical power systems using two nonlinear control synthesis techniques. For this transient stabilization problem the actuator considered is a power electronic device, a controllable series capacitor (CSC). The power system is described using two different nonlinear models - the second order swing equation and the third order flux-decay model. To start with, the CSC is modeled by the injection model which is based on the assumption that the CSC dynamics is very fast as compared to the dynamics of the power system and hence can be approximated by an algebraic equation. Here, by neglecting the CSC dynamics, the input vector g(x) in the open loop system takes a complex form - the injection model. Using this model, interconnection and damping assignment passivity-based control (IDA-PBC) methodology is demonstrated on two power systems: a single machine infinite bus (SMIB) system and a two machine system. Further, IDA-PBC is used to derive stabilizing controllers for power systems, where the CSC dynamics are included as a first order system. Next, we consider a different control methodology, immersion and invariance (I and I), to synthesize an asymptotically stabilizing control law for the SMIB system with a CSC. The CSC is described by a first order system. As a generalization of I and I, we incorporate the power balance algebraic constraints in the load bus to the SMIB swing equation, and extend the design philosophy to a class of differential algebraic systems. The proposed result is then demonstrated on another example: a two-machine system with two load buses and a CSC. The controller performances are validated through simulations for all cases.
Design Method for the Magnetic Bearing Control System with Fuzzy-PID Approach
Institute of Scientific and Technical Information of China (English)
XU Chun-guang; L(U) Dong-ming; HAO Juan
2008-01-01
The five degree freedom magnetic bearing is researched and its structure and working principles are introduced also.Based on the fuzzy control technology,combining fuzzy algorithm and PID control method,identifying the transition process mode of the online system to get the PID parameters'self-adjusting,the magnetic bearing system's Fuzzy-PID nonlinear controller is designed by analyzing the system control demands.The Fuzzy-PID nonlinear controller can deal with the magnetic bearing system's open loop instability and strong nonlinearity,and the approach could improve the system's rapidity,adaptability,stability and dynamic characteristics.Comparative analysis and experiments are conducted between linear PID and nonlinear fuzzyPID control methods,the results show that the fuzzy-PID controller is better,and the five-freedom magnetic bearing's rotary precision experiments are conducted by the fuzzy-PID controller,it satisfies the control rotary precision demands and realizes the bearing's steady floating and rotating.
Comparative Study of Controllers for a Variable Area MIMO Interacting NonLinear System
Directory of Open Access Journals (Sweden)
Priya Chandrasekar
2014-03-01
Full Text Available Most of the industrial processes are basically Multi Input Multi Output (MIMO system. In this paper a new combination of Spherical Conical Interacting Tank System (SCITS which is a variable area nonlinear MIMO system is considered for study and various control algorithms based on Ziegler Nichol’s tuning method, Hagglund Astrom Robust tuning method, Fractional Order (FO control and Passivity Based Control (PBC are used and compared for the level control of spherical tank system and conical tank system connected with interaction. Transfer function matrix of the system is obtained experimentally from the open loop response of the system. The designed controllers are tested for servo and regulatory operations. The controllers are compared in terms of time domain specification and performance index criterion. From the analysis of the simulation results, it is seen that FO controller gives improved performance when compared to conventional Integer Order (IO controller and overall Passivity Based Controller (PBCr gives improved performance comparatively for spherical conical interacting MIMO system.
Shao, Xingling; Wang, Honglun
2015-01-01
This paper investigates a novel compound control scheme combined with the advantages of trajectory linearization control (TLC) and alternative active disturbance rejection control (ADRC) for hypersonic reentry vehicle (HRV) attitude tracking system with bounded uncertainties. Firstly, in order to overcome actuator saturation problem, nonlinear tracking differentiator (TD) is applied in the attitude loop to achieve fewer control consumption. Then, linear extended state observers (LESO) are constructed to estimate the uncertainties acting on the LTV system in the attitude and angular rate loop. In addition, feedback linearization (FL) based controllers are designed using estimates of uncertainties generated by LESO in each loop, which enable the tracking error for closed-loop system in the presence of large uncertainties to converge to the residual set of the origin asymptotically. Finally, the compound controllers are derived by integrating with the nominal controller for open-loop nonlinear system and FL based controller. Also, comparisons and simulation results are presented to illustrate the effectiveness of the control strategy.
On-off and PI Control of Methane Gas Production of a Pilot Anaerobic Digestion Reactor
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Finn Haugen
2013-07-01
Full Text Available A proposed feedback control system for methane flow control of a real pilot anaerobic digestion reactor fed with dairy waste is designed and analyzed using the modified Hill model, which has previously been adapted to the reactor. Conditions for safe operation of the reactor are found using steady-state responses of dynamic simulations, taking into account the upper limit of the volatile fatty acids (VFA concentration recommended in the literature. The controllers used are standard process controllers, namely the on-off controller and the PI controller. Several PI controller tuning methods are evaluated using simulations. Two methods are favoured, namely the Skogestad method, which is an open loop method, and the Relaxed Ziegler-Nichols closed loop method. The two methods give approximately the same PI settings. Still, the Skogestad method is ranged first as it requires less tuning time, and because it is easier to change the PI settings at known changes in the process dynamics. Skogestad's method is successfully applied to a PI control system for the real reactor. Using simulations, the critical operating point to be used for safe controller tuning is identified.
Real time MHD mode control using ECCD in KSTAR: Plan and requirements
Energy Technology Data Exchange (ETDEWEB)
Joung, M.; Woo, M. H.; Jeong, J. H.; Hahn, S. H.; Yun, S. W.; Lee, W. R.; Bae, Y. S.; Oh, Y. K.; Kwak, J. G.; Yang, H. L. [National Fusion Research Institute, 52 Eoeun-dong, Yuseong-gu, Daejeon (Korea, Republic of); Namkung, W.; Park, H.; Cho, M. H. [Department of Physics, POSTECH, Hyoja-dong, Nam-gu, Pohang, Gyeongangbuk-do (Korea, Republic of); Kim, M. H.; Kim, K. J.; Na, Y. S. [Department of Nuclear Engineering, Seoul National University, Daehak-dong, Gwanak-gu, Seoul (Korea, Republic of); Hosea, J.; Ellis, R. [Princeton Plasma Physics Laboratory, Princeton (United States)
2014-02-12
For a high-performance, advanced tokamak mode in KSTAR, we have been developing a real-time control system of MHD modes such as sawtooth and Neo-classical Tearing Mode (NTM) by ECH/ECCD. The active feedback control loop will be also added to the mirror position and the real-time detection of the mode position. In this year, for the stabilization of NTM that is crucial to plasma performance we have implemented open-loop ECH antenna control system in KSTAR Plasma Control System (PCS) for ECH mirror movement during a single plasma discharge. KSTAR 170 GHz ECH launcher which was designed and fabricated by collaboration with PPPL and POSTECH has a final mirror of a poloidally and toroidally steerable mirror. The poloidal steering motion is only controlled in the real-time NTM control system and its maximum steering speed is 10 degree/sec by DC motor. However, the latency of the mirror control system and the return period of ECH antenna mirror angle are not fast because the existing launcher mirror control system is based on PLC which is connected to the KSTAR machine network through serial to LAN converter. In this paper, we present the design of real time NTM control system, ECH requirements, and the upgrade plan.
Edge state preparation in a one-dimensional lattice by quantum Lyapunov control
Zhao, X. L.; Shi, Z. C.; Qin, M.; Yi, X. X.
2017-01-01
Quantum Lyapunov control uses a feedback control methodology to determine control fields applied to control quantum systems in an open-loop way. In this work, we employ two Lyapunov control schemes to prepare an edge state for a fermionic chain consisting of cold atoms loaded in an optical lattice. Such a chain can be described by the Harper model. Corresponding to the two schemes, two types of quantum Lyapunov functions are considered. The results show that both the schemes are effective at preparing the edge state within a wide range of parameters. We found that the edge state can be prepared with high fidelity even if there are moderate fluctuations of on-site or hopping potentials. Both control schemes can be extended to similar chains (3m + d, d = 2) of different lengths. Since a regular amplitude control field is easier to apply in practice, an amplitude-modulated control field is used to replace the unmodulated one. Such control approaches provide tools to explore the edge states of one-dimensional topological materials.
Directory of Open Access Journals (Sweden)
Miaolei Zhou
Full Text Available As a new type of smart material, magnetic shape memory alloy has the advantages of a fast response frequency and outstanding strain capability in the field of microdrive and microposition actuators. The hysteresis nonlinearity in magnetic shape memory alloy actuators, however, limits system performance and further application. Here we propose a feedforward-feedback hybrid control method to improve control precision and mitigate the effects of the hysteresis nonlinearity of magnetic shape memory alloy actuators. First, hysteresis nonlinearity compensation for the magnetic shape memory alloy actuator is implemented by establishing a feedforward controller which is an inverse hysteresis model based on Krasnosel'skii-Pokrovskii operator. Secondly, the paper employs the classical Proportion Integration Differentiation feedback control with feedforward control to comprise the hybrid control system, and for further enhancing the adaptive performance of the system and improving the control accuracy, the Radial Basis Function neural network self-tuning Proportion Integration Differentiation feedback control replaces the classical Proportion Integration Differentiation feedback control. Utilizing self-learning ability of the Radial Basis Function neural network obtains Jacobian information of magnetic shape memory alloy actuator for the on-line adjustment of parameters in Proportion Integration Differentiation controller. Finally, simulation results show that the hybrid control method proposed in this paper can greatly improve the control precision of magnetic shape memory alloy actuator and the maximum tracking error is reduced from 1.1% in the open-loop system to 0.43% in the hybrid control system.
Zhou, Miaolei; Zhang, Qi; Wang, Jingyuan
2014-01-01
As a new type of smart material, magnetic shape memory alloy has the advantages of a fast response frequency and outstanding strain capability in the field of microdrive and microposition actuators. The hysteresis nonlinearity in magnetic shape memory alloy actuators, however, limits system performance and further application. Here we propose a feedforward-feedback hybrid control method to improve control precision and mitigate the effects of the hysteresis nonlinearity of magnetic shape memory alloy actuators. First, hysteresis nonlinearity compensation for the magnetic shape memory alloy actuator is implemented by establishing a feedforward controller which is an inverse hysteresis model based on Krasnosel'skii-Pokrovskii operator. Secondly, the paper employs the classical Proportion Integration Differentiation feedback control with feedforward control to comprise the hybrid control system, and for further enhancing the adaptive performance of the system and improving the control accuracy, the Radial Basis Function neural network self-tuning Proportion Integration Differentiation feedback control replaces the classical Proportion Integration Differentiation feedback control. Utilizing self-learning ability of the Radial Basis Function neural network obtains Jacobian information of magnetic shape memory alloy actuator for the on-line adjustment of parameters in Proportion Integration Differentiation controller. Finally, simulation results show that the hybrid control method proposed in this paper can greatly improve the control precision of magnetic shape memory alloy actuator and the maximum tracking error is reduced from 1.1% in the open-loop system to 0.43% in the hybrid control system.
Robust time and frequency domain estimation methods in adaptive control
Lamaire, Richard Orville
1987-01-01
A robust identification method was developed for use in an adaptive control system. The type of estimator is called the robust estimator, since it is robust to the effects of both unmodeled dynamics and an unmeasurable disturbance. The development of the robust estimator was motivated by a need to provide guarantees in the identification part of an adaptive controller. To enable the design of a robust control system, a nominal model as well as a frequency-domain bounding function on the modeling uncertainty associated with this nominal model must be provided. Two estimation methods are presented for finding parameter estimates, and, hence, a nominal model. One of these methods is based on the well developed field of time-domain parameter estimation. In a second method of finding parameter estimates, a type of weighted least-squares fitting to a frequency-domain estimated model is used. The frequency-domain estimator is shown to perform better, in general, than the time-domain parameter estimator. In addition, a methodology for finding a frequency-domain bounding function on the disturbance is used to compute a frequency-domain bounding function on the additive modeling error due to the effects of the disturbance and the use of finite-length data. The performance of the robust estimator in both open-loop and closed-loop situations is examined through the use of simulations.
Laser-error-correction control unit for machine tools
Energy Technology Data Exchange (ETDEWEB)
Burleson, R.R.
1978-05-23
An ultraprecision machining capability is needed for the laser fusion program. For this work, a precision air-bearing spindle has been mounted horizontally on a modified vertical column of a Moore Number 3 measuring machine base located in a development laboratory at the Oak Ridge Y-12 Plant. An open-loop control system previously installed on this machine was inadequate to meet the upcoming requirements since accuracy is limited to 0.5 ..mu..m by the errors in the machine's gears and leadscrew. A new controller was needed that could monitor the actual position of the machine and perform real-time error correction on the programmed tool path. It was necessary that this project: (1) attain an optimum tradeoff between hardware and software; (2) use a modular design for easy maintenance; (3) use a standard NC tape service; (4) drive the x and y axes with a positioning resolution of 5.08 nm and a feedback resolution of 10 nm; (5) drive the x and y axis motors at a velocity of 0.05 cm/sec in the contouring mode and 0.18 cm/sec in the positioning mode; (6) eliminate the possibility of tape-reader errors; and (7) allow editing of the part description data. The work that was done to develop and install the new machine controller is described.
Simulink Implementation of Indirect Vector Control of Induction Machine Model
Directory of Open Access Journals (Sweden)
V. Dhanunjayanaidu
2014-04-01
Full Text Available In this paper, a modular Simulink implementation of an induction machine model is described in a step-by-step approach. With the modular system, each block solves one of the model equations; therefore, unlike in black box models, all of the machine parameters are accessible for control and verification purposes.After the implementation, examples are given with the model used in different drive applications, such as open-loop constant V/Hz control and indirect vector control. To implement the induction machine model, the dynamic equivalent circuit of induction motor is taken and the model equations in flux linkage form are derived.Then the model is implemented in Simulink by transforming three phase voltages to d-q frame and the d-q currents back to three phase, also it includes unit vector calculation and induction machine d-q model.The inputs here are three phase voltages, load torque, speed of stator and the outputs are flux linkages and currents, electrical torque and speed of rotor.
Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit
2012-11-15
A novel manufacturing strategy based on continuous processing integrated with online monitoring tools coupled with efficient automatic feedback control system is highly desired for efficient Quality by Design (QbD) based manufacturing of the next generation of pharmaceutical products with optimal consumption of time, space and resources. In this manuscript, an efficient plant-wide control strategy for an integrated continuous pharmaceutical tablet manufacturing process via roller compaction has been designed in silico. The designed control system consists of five cascade control loops and three single control loops resulting in 42 controller tuning parameters. An effective controller parameter tuning strategy involving an ITAE method coupled with an optimization strategy has been proposed and the designed control system has been implemented in a first principle model-based flowsheet that was simulated in gPROMS (Process System Enterprise). The advanced techniques (e.g. anti-windup) have been employed to improve the performance of the control system. The ability of the control system to reject the unknown disturbances as well as to track the set point has been analyzed. Results demonstrated enhanced performance of critical quality attributes (CQAs) under closed-loop control compared to open-loop operation thus illustrating the potential of closed-loop feedback control in improving pharmaceutical manufacturing operations.
Dynamic Analysis and Control of the Clutch Filling Process in Clutch-to-Clutch Transmissions
Directory of Open Access Journals (Sweden)
Wei Guo
2014-01-01
Full Text Available Clutch fill control in clutch-to-clutch transmissions influences shift quality considerably. An oncoming clutch should be applied synchronously with the release of an offgoing clutch to shift gear smoothly; therefore, the gap between the piston and clutch plates should be eliminated when the torque capacity is near zero at the end of the clutch fill phase. Open-loop control is typically implemented for the clutch fill because of the cost of pressure sensor. Low control precision causes underfill or overfill to occur, deteriorating shift quality. In this paper, a mathematical model of an electrohydraulic clutch shift control system is presented. Special dynamic characteristic parameters for optimal clutch fill control are subsequently proposed. An automatic method for predicting initial fill control parameters is proposed to eliminate distinct discrepancies among transmissions caused by manufacturing or assembling errors. To prevent underfill and overfill, a fuzzy adaptive control method is proposed, in which clutch fill control parameters are adjusted self-adaptively and continually. Road vehicle test results proved that applying the fuzzy adaptive method ensures the consistency of shift quality even after the transmission’s status is changed.
Yuan, H.; Zhu, H.
2016-10-01
It is well known that backward motion control of an articulated vehicle is difficult because it is an open loop unstable system and such motion is also dangerous due to 'jackknifing'. In this paper, an anti-jackknife reverse tracking control strategy for autonomous articulated vehicles is proposed based on the combined longitudinal and lateral control scheme. In the proposed lateral-longitudinal control scheme, the major task is to control the reverse heading of the trailer by automatic steering strategies that observe both the anti-jackknife condition and input limitations. The main contribution of this paper is the development of globally asymptotic anti-jackknife stabilising and tracking controls of heading angles with both state and input constraints considered a priori. The proposed control inherently has an anti-windup mechanism that prevents the hitch angle from going beyond any specified critical value to avoid jackknifing, during which time, the steering angle remains at its limit. Stability of the controller is theoretically proven via the Lyapunov argument. Effectiveness of the proposed approach is demonstrated by CarSim and Simulink joint simulations.
Cluster-based control of a separating flow over a smoothly contoured ramp
Kaiser, Eurika; Noack, Bernd R.; Spohn, Andreas; Cattafesta, Louis N.; Morzyński, Marek
2017-01-01
The ability to manipulate and control fluid flows is of great importance in many scientific and engineering applications. The proposed closed-loop control framework addresses a key issue of model-based control: The actuation effect often results from slow dynamics of strongly nonlinear interactions which the flow reveals at timescales much longer than the prediction horizon of any model. Hence, we employ a probabilistic approach based on a cluster-based discretization of the Liouville equation for the evolution of the probability distribution. The proposed methodology frames high-dimensional, nonlinear dynamics into low-dimensional, probabilistic, linear dynamics which considerably simplifies the optimal control problem while preserving nonlinear actuation mechanisms. The data-driven approach builds upon a state space discretization using a clustering algorithm which groups kinematically similar flow states into a low number of clusters. The temporal evolution of the probability distribution on this set of clusters is then described by a control-dependent Markov model. This Markov model can be used as predictor for the ergodic probability distribution for a particular control law. This probability distribution approximates the long-term behavior of the original system on which basis the optimal control law is determined. We examine how the approach can be used to improve the open-loop actuation in a separating flow dominated by Kelvin-Helmholtz shedding. For this purpose, the feature space, in which the model is learned, and the admissible control inputs are tailored to strongly oscillatory flows.
Testing and commissioning the multinode ECRH realtime control system on the FTU tokamak
Energy Technology Data Exchange (ETDEWEB)
Galperti, C., E-mail: galperti@ifp.cnr.it [EURATOM – ENEA – CNR Fusion Association, CNR-IFP, via R. Cozzi 53, 20125 Milan (Italy); Boncagni, L., E-mail: luca.boncagni@enea.it [EURATOM – ENEA – CNR Fusion Association, Frascati Research Center, Division of Fusion Physics, Rome, Frascati (Italy); Alessi, E.; Sozzi, C.; Nowak, S.; Granucci, G.; Minelli, D.; Marchetto, C. [EURATOM – ENEA – CNR Fusion Association, CNR-IFP, via R. Cozzi 53, 20125 Milan (Italy)
2014-03-15
Highlights: • We conceived, developed and commissioned a distributed multinode control hardware with proven real-time performances. • The adopted hardware solution is modular and reconfigurable. • The adopted software solution is able to host many experimental scenarios and is totally remotely programmable, configurable and testable. • Effective results in on-line MHD instability detection are presented. - Abstract: In tokamak machines, the ECRH heating system is crucial for plasma heating and for stability control. To be reliable, an ECRH control system should be deeply integrated into the supervision and control systems of the machine, and must be interconnected to the diagnostic instruments and the power actuators of the plant. Moreover, several ECRH experiments are under investigation by the community. So, for the sake of efficiency, it should be possible to reprogram a control system on the fly and possibly from remote locations, even during experiment campaigns. This paper presents the new ECRH control system under development at the FTU tokamak. This system consists of multiple units that acquire and process data and are linked through Ethernet and dedicated fiber-optic data links, under a Linux/MARTe framework. This paper also presents open-loop operative results, both about performances of the control system and about signal processing of the diagnostics relevant to MHD control.
Dynamic Steering Control of Battery Operated Car for Lane Keeping using Image Sensor
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Ankit Sharma
2011-01-01
Full Text Available This project presents simple prototype for driving automation of battery operated cars. The system consists of Decision Making Unit (DMU & Control System Unit (CSU to implement decision given by DMU. DMU performs the task of image acquisition, enhancing, thresholding, noise reduction, calculation of the position of car with respect to lanes and estimation of the desired position. DMU communicate with CSU using UART serial protocol, thereby informing CSU to take necessary control action regarding - speed control & position control of steering wheel. Speed control is an open loop system which controls the two DC motors powering the front wheels of car. Mechanical hardware for position control of steering wheel contains a high torque DC motor which is coupled to steering wheel using gears in mesh configuration. The control algorithm used here is digital PID algorithm. The PID is digitized using trapezoidal approximation, Newton’s backward difference method to approximate integration & differentiation. Feedback signal is generated by 47kΩ potentiometer which gives a output of 0-5 volt. The algorithm based on these methods has been programmed in the Atmega16 which drives the dc motor coupled with steering wheel using L293d motor driver.
Proportional and Integral Thermal Control System for Large Scale Heating Tests
Fleischer, Van Tran
2015-01-01
The National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) Flight Loads Laboratory is a unique national laboratory that supports thermal, mechanical, thermal/mechanical, and structural dynamics research and testing. A Proportional Integral thermal control system was designed and implemented to support thermal tests. A thermal control algorithm supporting a quartz lamp heater was developed based on the Proportional Integral control concept and a linearized heating process. The thermal control equations were derived and expressed in terms of power levels, integral gain, proportional gain, and differences between thermal setpoints and skin temperatures. Besides the derived equations, user's predefined thermal test information generated in the form of thermal maps was used to implement the thermal control system capabilities. Graphite heater closed-loop thermal control and graphite heater open-loop power level were added later to fulfill the demand for higher temperature tests. Verification and validation tests were performed to ensure that the thermal control system requirements were achieved. This thermal control system has successfully supported many milestone thermal and thermal/mechanical tests for almost a decade with temperatures ranging from 50 F to 3000 F and temperature rise rates from -10 F/s to 70 F/s for a variety of test articles having unique thermal profiles and test setups.
Comparative Study of SSVEP- and P300-Based Models for the Telepresence Control of Humanoid Robots.
Directory of Open Access Journals (Sweden)
Jing Zhao
Full Text Available In this paper, we evaluate the control performance of SSVEP (steady-state visual evoked potential- and P300-based models using Cerebot-a mind-controlled humanoid robot platform. Seven subjects with diverse experience participated in experiments concerning the open-loop and closed-loop control of a humanoid robot via brain signals. The visual stimuli of both the SSVEP- and P300- based models were implemented on a LCD computer monitor with a refresh frequency of 60 Hz. Considering the operation safety, we set the classification accuracy of a model over 90.0% as the most important mandatory for the telepresence control of the humanoid robot. The open-loop experiments demonstrated that the SSVEP model with at most four stimulus targets achieved the average accurate rate about 90%, whereas the P300 model with the six or more stimulus targets under five repetitions per trial was able to achieve the accurate rates over 90.0%. Therefore, the four SSVEP stimuli were used to control four types of robot behavior; while the six P300 stimuli were chosen to control six types of robot behavior. Both of the 4-class SSVEP and 6-class P300 models achieved the average success rates of 90.3% and 91.3%, the average response times of 3.65 s and 6.6 s, and the average information transfer rates (ITR of 24.7 bits/min 18.8 bits/min, respectively. The closed-loop experiments addressed the telepresence control of the robot; the objective was to cause the robot to walk along a white lane marked in an office environment using live video feedback. Comparative studies reveal that the SSVEP model yielded faster response to the subject's mental activity with less reliance on channel selection, whereas the P300 model was found to be suitable for more classifiable targets and required less training. To conclude, we discuss the existing SSVEP and P300 models for the control of humanoid robots, including the models proposed in this paper.
Comparative Study of SSVEP- and P300-Based Models for the Telepresence Control of Humanoid Robots.
Zhao, Jing; Li, Wei; Li, Mengfan
2015-01-01
In this paper, we evaluate the control performance of SSVEP (steady-state visual evoked potential)- and P300-based models using Cerebot-a mind-controlled humanoid robot platform. Seven subjects with diverse experience participated in experiments concerning the open-loop and closed-loop control of a humanoid robot via brain signals. The visual stimuli of both the SSVEP- and P300- based models were implemented on a LCD computer monitor with a refresh frequency of 60 Hz. Considering the operation safety, we set the classification accuracy of a model over 90.0% as the most important mandatory for the telepresence control of the humanoid robot. The open-loop experiments demonstrated that the SSVEP model with at most four stimulus targets achieved the average accurate rate about 90%, whereas the P300 model with the six or more stimulus targets under five repetitions per trial was able to achieve the accurate rates over 90.0%. Therefore, the four SSVEP stimuli were used to control four types of robot behavior; while the six P300 stimuli were chosen to control six types of robot behavior. Both of the 4-class SSVEP and 6-class P300 models achieved the average success rates of 90.3% and 91.3%, the average response times of 3.65 s and 6.6 s, and the average information transfer rates (ITR) of 24.7 bits/min 18.8 bits/min, respectively. The closed-loop experiments addressed the telepresence control of the robot; the objective was to cause the robot to walk along a white lane marked in an office environment using live video feedback. Comparative studies reveal that the SSVEP model yielded faster response to the subject's mental activity with less reliance on channel selection, whereas the P300 model was found to be suitable for more classifiable targets and required less training. To conclude, we discuss the existing SSVEP and P300 models for the control of humanoid robots, including the models proposed in this paper.
Feedback shape control for deployable mesh reflectors using gain scheduling method
Xie, Yangmin; Shi, Hang; Alleyne, Andrew; Yang, Bingen
2016-04-01
This paper presents a theoretical study on the dynamic shape control problem of deployable mesh reflectors (DMRs) via feedback approaches. The reflector structure is simplified from a nonlinear model to be quasi-static with respect to temperature variations but dynamic with respect to mechanical vibrations. The orbital cycle is segmented into multiple temperature zones, and an H∞ robust state feedback controller is designed for each zone to guarantee the local stability of the system under the model uncertainty caused by thermal effects and to reject external force disturbances. At the same time, gain scheduling control method is adopted to compensate thermal distortions and to ensure smooth transition response when switching among the local robust controllers. A DMR model is considered in the case study to show the effectiveness of the control approach. The structural vibrations caused by external force disturbances can be sufficiently suppressed in a much shorter time. The closed loop response of the DMR structure shows that much higher surface accuracy is obtained during the orbiting mission compared to the open-loop configuration, and transient focal length and transient de-focus of the reflector are well controlled within the satisfactory bounds, demonstrating the numerical feasibility of the proposed method to solve the dynamic shape control problem of DMRs.
Multichannel control systems for the attenuation of interior road noise in vehicles
Cheer, Jordan; Elliott, Stephen J.
2015-08-01
This paper considers the active control of road noise in vehicles, using either multichannel feedback control, with both headrest and floor positioned microphones providing feedback error signals, or multichannel feedforward control, in which reference signals are provided by the microphones on the vehicle floor and error signals are provided by the microphones mounted on the headrests. The formulation of these control problems is shown to be similar if the constraints of robust stability, limited disturbance enhancement and open-loop stability are imposed. A novel formulation is presented for disturbance enhancement in multichannel systems, which limits the maximum enhancement of each individual error signal. The performance of these two systems is predicted using plant responses and disturbance signals measured in a small city car. The reduction in the sum of the squared pressure signals at the four error microphones for both systems is found to be up to 8 dB at low frequencies and 3 dB on average, where the sound level is particularly high from 80 to 180 Hz. The performance of both systems is found to be robust to measured variations in the plant responses. The enhancements in the disturbance at higher frequencies are smaller for the feedback controller than for the feedforward controller, although the performance of the feedback controller is more significantly reduced by the introduction of additional delay in the plant response.
Closed loop statistical performance analysis of N-K knock controllers
Peyton Jones, James C.; Shayestehmanesh, Saeed; Frey, Jesse
2017-09-01
The closed loop performance of engine knock controllers cannot be rigorously assessed from single experiments or simulations because knock behaves as a random process and therefore the response belongs to a random distribution also. In this work a new method is proposed for computing the distributions and expected values of the closed loop response, both in steady state and in response to disturbances. The method takes as its input the control law, and the knock propensity characteristic of the engine which is mapped from open loop steady state tests. The method is applicable to the 'n-k' class of knock controllers in which the control action is a function only of the number of cycles n since the last control move, and the number k of knock events that have occurred in this time. A Cumulative Summation (CumSum) based controller falls within this category, and the method is used to investigate the performance of the controller in a deeper and more rigorous way than has previously been possible. The results are validated using onerous Monte Carlo simulations, which confirm both the validity of the method and its high computational efficiency.
Design and implementation of FPGA-based phase modulation control for series resonant inverters
Indian Academy of Sciences (India)
N Gayathri; M C Chandorkar
2008-10-01
Owing to the tremendous advances in the digital technology, and improved reliability and performance of the digital control mechanisms, this paper focuses on design and implementation of digital controller using FPGA-based circuit design approach. The digital controller proposed is designed for series resonant inverter used in DC–DC converter applications. Phase modulation technique is proposed for the realization of digital controller on FPGA. The Series Resonant Converter (SRC) is considered in this paper as a preferred converter topology for high power, high voltage power supplies. This paper studies the implementation of phase shift modulation technique using FPGA. The inverter designed, is IGBT based, and Zero Voltage Switching (ZVS) technique is implemented due to reduced stresses on devices and increased efﬁciency. The phase modulated series resonant inverters (PM-SRC) promotes ZVS operation when its switching frequency is greater than resonant frequency. The designed PM controller is realized using FPGA on which control algorithm and other features of a controller are developed. The series resonant inverter is built and tested for full load under open loop and closed loop conditions at a switching frequency of 20 kHz. The results are presented under varying load conditions. The simulation and the experimental results were found to match closely.
Low-cost feedback-controlled syringe pressure pumps for microfluidics applications
Lake, John R.; Heyde, Keith C.
2017-01-01
Microfluidics are widely used in research ranging from bioengineering and biomedical disciplines to chemistry and nanotechnology. As such, there are a large number of options for the devices used to drive and control flow through microfluidic channels. Commercially available syringe pumps are probably the most commonly used instruments for this purpose, but are relatively high-cost and have inherent limitations due to their flow profiles when they are run open-loop. Here, we present a low-cost ($110) syringe pressure pump that uses feedback control to regulate the pressure into microfluidic chips. Using an open-source microcontroller board (Arduino), we demonstrate an easily operated and programmable syringe pump that can be run using either a PID or bang-bang control method. Through feedback control of the pressure at the inlets of two microfluidic geometries, we have shown stability of our device to within ±1% of the set point using a PID control method and within ±5% of the set point using a bang-bang control method with response times of less than 1 second. This device offers a low-cost option to drive and control well-regulated pressure-driven flow through microfluidic chips. PMID:28369134
Dores, Delfim Zambujo Das
2005-11-01
Engineering research over the last few years has successfully demonstrated the potential of thrust vector control using counterflow at conditions up to Mach 2. Flow configurations that include the pitch vectoring of rectangular jets and multi-axis vector control in diamond and axisymmetric nozzle geometries have been studied. Although bistable (on-off) fluid-based control has been around for some time, the present counterflow thrust vector control is unique because proportional and continuous jet response can be achieved in the absence of moving parts, while avoiding jet attachment, which renders most fluidic approaches unacceptable for aircraft and missile control applications. However, before this study, research had been limited to open-loop studies of counterflow thrust vectoring. For practical implementation it was vital that the counterflow scheme be used in conjunction with feedback control. Hence, the focus of this research was to develop and experimentally demonstrate a feedback control design methodology for counterflow thrust vectoring. This research focused on 2-D (pitch) thrust vectoring and addresses four key modeling issues. The first issue is to determine the measured variable to be commanded since the thrust vector angle is not measurable in real time. The second related issue is to determine the static mapping from the thrust vector angle to this measured variable. The third issue is to determine the dynamic relationship between the measured variable and the thrust vector angle. The fourth issue is to develop dynamic models with uncertainty characterizations. The final and main goal was the design and implementation of robust controllers that yield closed-loop systems with fast response times, and avoid overshoot in order to aid in the avoidance of attachment. These controllers should be simple and easy to implement in real applications. Hence, PID design has been chosen. Robust control design is accomplished by using ℓ1 control theory in
Application of Statistical Process Control Methods for IDS
Directory of Open Access Journals (Sweden)
Muhammad Sadiq Ali Khan
2012-11-01
Full Text Available As technology improves, attackers are trying to get access to the network system resources by so many means. Open loop holes in the network allow them to penetrate in the network more easily; statistical methods have great importance in the area of computer and network security, in detecting the malfunctioning of the network system. Development of internet security solution needed to protect the system and to with stand prolonged and diverse attack. In this paper Statistical approach has been used, conventionally Statistical Control Charts has been used for quality characteristics however in IDS abnormal access can be easily detected and appropriate control limit can be established. Two different charts are investigated and Shewhart chart based on average has produced better accuracy. The approach used here for intrusion detection in such a way that if the data packet is drastically different from normal variation then it can be classified as attack. In other words a system variation may be due to some special reason. If these causes are investigated then natural variation and abnormal variation can be distinguished which can be used for distinction of behaviors of the system.
Integrated Robot-Human Control in Mining Operations
Energy Technology Data Exchange (ETDEWEB)
George Danko
2007-09-30
This report contains a detailed description of the work conducted for the project on Integrated Robot-Human Control in Mining Operations at University of Nevada, Reno. This project combines human operator control with robotic control concepts to create a hybrid control architecture, in which the strengths of each control method are combined to increase machine efficiency and reduce operator fatigue. The kinematics reconfiguration type differential control of the excavator implemented with a variety of 'software machine kinematics' is the key feature of the project. This software re-configured excavator is more desirable to execute a given digging task. The human operator retains the master control of the main motion parameters, while the computer coordinates the repetitive movement patterns of the machine links. These repetitive movements may be selected from a pre-defined family of trajectories with different transformations. The operator can make adjustments to this pattern in real time, as needed, to accommodate rapidly-changing environmental conditions. A working prototype has been developed using a Bobcat 435 excavator. The machine is operational with or without the computer control system depending on whether the computer interface is on or off. In preparation for emulated mining tasks tests, typical, repetitive tool trajectories during surface mining operations were recorded at the Newmont Mining Corporation's 'Lone Tree' mine in Nevada. Analysis of these working trajectories has been completed. The motion patterns, when transformed into a family of curves, may serve as the basis for software-controlled machine kinematics transformation in the new human-robot control system. A Cartesian control example has been developed and tested both in simulation and on the experimental excavator. Open-loop control is robustly stable and free of short-term dynamic problems, but it allows for drifting away from the desired motion kinematics of the
Institute of Scientific and Technical Information of China (English)
丁继斌
2011-01-01
应用AMESim对后装压缩式垃圾车专用装置反馈控制系统进行建模与仿真,对比分析了开环、闭环专用装置的运动特性.仿真结果表明:反馈控制系统可明显改善专用装置的运动状况,为提高专用装置的设计水平提供了参考.%Modeling and simulation of feedback control of special device hydraulic system for back-loaded and compressed refuse collector were carried out by AMEsim. Kinematic characteristics for opening loop and closed loop control system were compared and analyzed. The simulation results show that the feedback control system has good kinematic quality. It provides references for advancing the special device design level.
Power and Performance Management in Nonlinear Virtualized Computing Systems via Predictive Control.
Wen, Chengjian; Mu, Yifen
2015-01-01
The problem of power and performance management captures growing research interest in both academic and industrial field. Virtulization, as an advanced technology to conserve energy, has become basic architecture for most data centers. Accordingly, more sophisticated and finer control are desired in virtualized computing systems, where multiple types of control actions exist as well as time delay effect, which make it complicated to formulate and solve the problem. Furthermore, because of improvement on chips and reduction of idle power, power consumption in modern machines shows significant nonlinearity, making linear power models(which is commonly adopted in previous work) no longer suitable. To deal with this, we build a discrete system state model, in which all control actions and time delay effect are included by state transition and performance and power can be defined on each state. Then, we design the predictive controller, via which the quadratic cost function integrating performance and power can be dynamically optimized. Experiment results show the effectiveness of the controller. By choosing a moderate weight, a good balance can be achieved between performance and power: 99.76% requirements can be dealt with and power consumption can be saved by 33% comparing to the case with open loop controller.
Design and realization of JT-60SA Fast Plasma Position Control Coils power supplies
Energy Technology Data Exchange (ETDEWEB)
Zito, P., E-mail: pietro.zito@enea.it [National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Via E. Fermi, N. 45, 00044 Frascati (Italy); Lampasi, A. [National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Via E. Fermi, N. 45, 00044 Frascati (Italy); Coletti, A.; Novello, L. [Fusion for Energy (F4E) Broader Fusion Development Department, Garching (Germany); Matsukawa, M.; Shimada, K. [Japan Atomic Energy Agency (JAEA), Naka Fusion Institute, Mukouyama, Naka-si, Ibaraki-ken (Japan); Cinarelli, D.; Portesine, M. [POSEICO, via Pillea 42-44, 16152 Genova (Italy); Dorronsoro, A.; Vian, D. [JEMA, Paseo del Circuito 10, 20160 Lasarte-Oria Gipuzkoa (Spain)
2015-10-15
Highlights: • Fast Plasma Position Control Coils PSs control the vertical position of the plasma during a plasma shot. • The design phase was developed considering of providing full voltage at any current level. • The testing phase was successfully completed, according to the IEC60146 standards. • The measured rise time of the voltage response is 2.88 ms for a reference voltage step of 1 kV. - Abstract: Fast Plasma Position Control Coils (FPPCC) PSs control the vertical position of the plasma during a plasma shot, to prevent Vertical Displacement Event (VDE), using FPPC coils installed in vacuum vessel for JT-60SA. For this task, the FPPCC PSs have to be very fast for reacting to plasma movements. Further, an open loop feed forward voltage control is adopted in order to achieve a fast control of FPPCC PSs. The main characteristics are: 4-quadrant AC/DC converter 12-pulse with circulating current, DC load voltage ±1000 V and DC load current ±5 kA. The overvoltage induced by FPPC coil during a plasma disruption can reach 10 kV and it is protected by a nonlinear resistor in parallel to the crowbar up to its intervention. All these technical characteristics have strongly influenced the design of the FPPCC converter and transformers which have been validated by simulation model of FPPCC PS. The outcomes of the simulation allowed to finalize the performances and dynamic behavior of voltage response.
Power and Performance Management in Nonlinear Virtualized Computing Systems via Predictive Control.
Directory of Open Access Journals (Sweden)
Chengjian Wen
Full Text Available The problem of power and performance management captures growing research interest in both academic and industrial field. Virtulization, as an advanced technology to conserve energy, has become basic architecture for most data centers. Accordingly, more sophisticated and finer control are desired in virtualized computing systems, where multiple types of control actions exist as well as time delay effect, which make it complicated to formulate and solve the problem. Furthermore, because of improvement on chips and reduction of idle power, power consumption in modern machines shows significant nonlinearity, making linear power models(which is commonly adopted in previous work no longer suitable. To deal with this, we build a discrete system state model, in which all control actions and time delay effect are included by state transition and performance and power can be defined on each state. Then, we design the predictive controller, via which the quadratic cost function integrating performance and power can be dynamically optimized. Experiment results show the effectiveness of the controller. By choosing a moderate weight, a good balance can be achieved between performance and power: 99.76% requirements can be dealt with and power consumption can be saved by 33% comparing to the case with open loop controller.
Space Weather Influence on Relative Motion Control using the Touchless Electrostatic Tractor
Hogan, Erik A.; Schaub, Hanspeter
2016-09-01
With recent interest in the use of electrostatic forces for contactless tugging and attitude control of noncooperative objects for orbital servicing and active debris mitigation, the need for a method of remote charge control arises. In this paper, the use of a directed electron beam for remote charge control is considered in conjunction with the relative motion control. A tug vehicle emits an electron beam onto a deputy object, charging it negatively. At the same time, the tug is charged positively due to beam emission, resulting in an attractive electrostatic force. The relative position feedback control between the tug and the passive debris object is studied subject to the charging being created through an electron beam. Employing the nominal variations of the GEO space weather conditions across longitude slots, two electrostatic tugging strategies are considered. First, the electron beam current is adjusted throughout the orbit in order to maximize this resulting electrostatic force. This open-loop control strategy compensates for changes in the nominally expected local space weather environment in the GEO region to adjust for fluctuations in the local plasma return currents. Second, the performance impact of using a fixed electron beam current on the electrostatic tractor is studied if the same natural space weather variations are assumed. The fixed electron beam current shows a minor performance penalty (<5 %) while providing a much simpler implementation that does not require any knowledge of local space weather conditions.
Software-Based Wireless Power Transfer Platform for Various Power Control Experiments
Directory of Open Access Journals (Sweden)
Sun-Han Hwang
2015-07-01
Full Text Available In this paper, we present the design and evaluation of a software-based wireless power transfer platform that enables the development of a prototype involving various open- and closed-loop power control functions. Our platform is based on a loosely coupled planar wireless power transfer circuit that uses a class-E power amplifier. In conjunction with this circuit, we implement flexible control functions using a National Instruments Data Acquisition (NI DAQ board and algorithms in the MATLAB/Simulink. To verify the effectiveness of our platform, we conduct two types of power-control experiments: a no-load or metal detection using open-loop power control, and an output voltage regulation for different receiver positions using closed-loop power control. The use of the MATLAB/Simulink software as a part of the planar wireless power transfer platform for power control experiments is shown to serve as a useful and inexpensive alternative to conventional hardware-based platforms.
Mode selective control of drift wave turbulence
DEFF Research Database (Denmark)
Schröder, C.; Klinger, T.; Block, D.;
2001-01-01
Experiments on spatiotemporal open-loop synchronization of drift wave turbulence in a magnetized cylindrical plasma are reported. The synchronization effect is modeled by a rotating current profile with prescribed mode structure. Numerical simulations of an extended Hasegawa-Wakatani model show g...
Directory of Open Access Journals (Sweden)
Park Giseo
2016-01-01
Full Text Available Electro-Mechanical Brake (EMB is expected to be one of the future brake system. Feedback controller with sensor measuring is commonly used for control of EMB. However, this controller has some issues like delayed response and extra cost about sensor installation. In this paper, Feed-forward controller in EMB is proposed for solving these problems of feedback control. Also, it is very necessary to describe dynamical phenomenon of friction in actual EMB system. The actual EMB system shows stick-slip friction of mechanical parts which is difficult to model and apply to design of controller. This research is focused on exquisitely describing this stick-slip friction. In order to do this, the experiment about EMB is proceeded in the open loop system with the motor current command and data from the experiment is used for identification of model parameters during stiction. Then, parameters during slip is estimated in the closed loop system. Finally, developed friction model of EMB is proposed and it is utilized for design of feed-forward controller. Matlab Simulink is used for design of EMB simulation model and EMB test bench is utilized for experiment. Performance of proposed control system is compared with that of feedback control system.
Blain, Celia; Bradley, Colin; Guyon, Olivier; Vogel, Curtis
2010-01-01
In order to evaluate the potential of MEMS deformable mirrors for open-loop applications, a complete calibration process was performed on a 1024-actuator mirror. The mirror must be perfectly calibrated to obtain deterministic membrane deflection. The actuator's stroke-voltage relationship and the effect of the non- additivity of the influence functions are studied and finally integrated in an open-loop control process. This experiment aimed at minimizing the residual error obtained in open-loop control.
IMC based robust PID controller tuning for disturbance rejection
Institute of Scientific and Technical Information of China (English)
Mohammad Shamsuzzoha
2016-01-01
It is well-known that the IMC-PID controller tuning gives fast and improved set point response but slow disturbance rejection. A modification has been proposed in IMC-PID tuning rule for the improved disturbance rejection. For the modified IMC-PID tuning rule, a method has been developed to obtain the IMC-PID setting in closed-loop mode without acquiring detailed information of the process. The proposed method is based on the closed-loop step set point experiment using a proportional only controller with gainKc0. It is the direct approach to find the PID controller setting similar to classical Ziegler-Nichols closed-loop method. Based on simulations of a wide range of first-order with delay processes, a simple correlation has been derived to obtain the modified IMC-PID controller settings from closed-loop experiment. In this method, controller gain is a function of the overshoot obtained in the closed loop set point experiment. The integral and derivative time is mainly a function of the time to reach the first peak (overshoot). Simulation has been conducted for the broad class of processes and the controllers were tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison. The PID controller settings obtained in the proposed tuning method show better performance and robustness with other two-step tuning methods for the broad class of processes. It has also been applied to temperature control loop in distillation column model. The result has been compared to the open loop tuning method where it gives robust and fast response.
Design of Robust Adaptive Unbalance Response Controllers for Rotors with Magnetic Bearings
Knospe, Carl R.; Tamer, Samir M.; Fedigan, Stephen J.
1996-01-01
Experimental results have recently demonstrated that an adaptive open loop control strategy can be highly effective in the suppression of unbalance induced vibration on rotors supported in active magnetic bearings. This algorithm, however, relies upon a predetermined gain matrix. Typically, this matrix is determined by an optimal control formulation resulting in the choice of the pseudo-inverse of the nominal influence coefficient matrix as the gain matrix. This solution may result in problems with stability and performance robustness since the estimated influence coefficient matrix is not equal to the actual influence coefficient matrix. Recently, analysis tools have been developed to examine the robustness of this control algorithm with respect to structured uncertainty. Herein, these tools are extended to produce a design procedure for determining the adaptive law's gain matrix. The resulting control algorithm has a guaranteed convergence rate and steady state performance in spite of the uncertainty in the rotor system. Several examples are presented which demonstrate the effectiveness of this approach and its advantages over the standard optimal control formulation.
Taoka, Hidekazu; Morimoto, Akihito; Kawai, Hiroyuki; Higuchi, Kenichi; Sawahashi, Mamoru
This paper presents the best transmit diversity schemes for three types of common/shared control signals from the viewpoint of the block error rate (BLER) performance in the Evolved UTRA downlink employing OFDM radio access. This paper also presents the coverage performance of the common/shared control signals using transmit diversity with respect to the outage probability that satisfies the required BLER performance, which is a major factor determining the cell configuration. Simulation results clarify that Space-Frequency Block Code (SFBC) and the combination of SFBC and Frequency Switched Transmit Diversity (FSTD) are the best transmit diversity schemes among the open-loop type transmit diversity candidates for two-antenna and four-antenna transmission cases, respectively. Furthermore, we show through system-level simulations that SFBC is very effective in reducing the outage probability at the required BLER for the physical broadcast channel (PBCH), for the common control signal with resource block (RB)-level assignment such as the dynamic broadcast channel (D-BCH) and paging channel (PCH), and in increasing the number of accommodated L1/L2 control signals over one transmission time interval duration, using mini-control channel element (CCE)-level assignment.
Integration of Online Parameter Identification and Neural Network for In-Flight Adaptive Control
Hageman, Jacob J.; Smith, Mark S.; Stachowiak, Susan
2003-01-01
An indirect adaptive system has been constructed for robust control of an aircraft with uncertain aerodynamic characteristics. This system consists of a multilayer perceptron pre-trained neural network, online stability and control derivative identification, a dynamic cell structure online learning neural network, and a model following control system based on the stochastic optimal feedforward and feedback technique. The pre-trained neural network and model following control system have been flight-tested, but the online parameter identification and online learning neural network are new additions used for in-flight adaptation of the control system model. A description of the modification and integration of these two stand-alone software packages into the complete system in preparation for initial flight tests is presented. Open-loop results using both simulation and flight data, as well as closed-loop performance of the complete system in a nonlinear, six-degree-of-freedom, flight validated simulation, are analyzed. Results show that this online learning system, in contrast to the nonlearning system, has the ability to adapt to changes in aerodynamic characteristics in a real-time, closed-loop, piloted simulation, resulting in improved flying qualities.
MHD control experiments in the Extrap T2R Reversed Field Pinch
Marrelli, L.; Bolzonella, T.; Brunsell, P.; Cecconello, M.; Drake, J.; Franz, P.; Gregoratto, D.; Manduchi, G.; Martin, P.; Ortolani, S.; Paccagnella, R.; Piovesan, P.; Spizzo, G.; Yadikin, D.; Zanca, P.
2004-11-01
We report here on MHD active control experiments performed in the Extrap T2R device, which has been recently equipped with a set of 32 feedback controlled saddle coils couples. Experiments aiming at selectively exciting a resonant resistive instability in order to actively induce Quasi Single Helicity states will be presented. Open loop experiments have in fact shown that a spectrum with one dominant mode can be excited in a high aspect ratio device like T2R. In addition, evidences of controlled braking of tearing modes, which spontaneously rotate in T2R, have been gathered, allowing the determination of a threshold for mode wall locking. Different feedback control schemes have been implemented. In particular, mode suppression schemes proved successful in delaying resistive wall modes growth and in increasing the discharge duration: this suggests a hybrid mode control scenario, in which RWM are suppressed and QSH is induced. Radiation imaging and internal magnetic field reconstructions performed with the ORBIT code will be presented.
Real-time closed-loop control for micro mirrors with quasistatic comb drives
Schroedter, Richard; Sandner, Thilo; Janschek, Klaus; Roth, Matthias; Hruschka, Clemens
2016-03-01
This paper presents the application of a real-time closed-loop control for the quasistatic axis of electrostatic micro scanning mirrors. In comparison to resonantly driven mirrors, the quasistatic comb drive allows arbitrary motion profiles with frequencies up to its eigenfrequency. A current mirror setup at Fraunhofer IPMS is manufactured with a staggered vertical comb (SVC) drive and equipped with an integrated piezo-resistive deflection sensor, which can potentially be used as position feedback sensor. The control design is accomplished based on a nonlinear mechatronic system model and the preliminary parameter characterization. In previous papers [1, 2] we have shown that jerk-limited trajectories, calculated offline, provide a suitable method for parametric trajectory design, taking into account physical limitations given by the electrostatic comb and thus decreasing the dynamic requirements. The open-loop control shows in general unfavorable residual eigenfrequency oscillations leading to considerable tracking errors for desired triangle trajectories [3]. With real-time closed-loop control, implemented on a dSPACE system using an optical feedback, we can significantly reduce these errors and stabilize the mirror motion against external disturbances. In this paper we compare linear and different nonlinear closed-loop control strategies as well as two observer variants for state estimation. Finally, we evaluate the simulation and experimental results in terms of steady state accuracy and the concept feasibility for a low-cost realization.
Evaluation of selected control strategies for fed-batch cultures of a hybridoma cell line.
Pörtner, Ralf; Schwabe, Jan-Oliver; Frahm, Björn
2004-08-01
While fed-batch suspension culture of animal cells continues to be of industrial importance for the large-scale production of pharmaceutical products, existing control concepts are still insufficient. The present paper illustrates the advantages and disadvantages of different fed-batch strategies, including fixed-feed trajectories, control via OUR (oxygen uptake rate) (stoichiometric feeding), a priori determination of feed trajectories based on a kinetic model and the model-based adaptive OLFO (open-loop-feedback-optimal) control strategy. A recommendation as to which control strategy should be used for a specific process has to consider the respective process. For an established process with a well characterized and stable production cell line, probably the application of a fixed feed trajectory should be recommended. An adaptive, model-based control strategy could be the method of choice during cell-line development or for rapid production of small amounts of product for clinical trials, owing to its universal character and because it does not require intensive process development.
Pressure Control of Electro-Hydraulic Servovalve and Transmission Line Effect
Directory of Open Access Journals (Sweden)
Ahmed Fouad Mahdi
2013-06-01
Full Text Available The effected of the long transmission line (TL between the actuator and the hydraulic control valve sometimes essentials. The study is concerned with modeling the TL which carries the oil from the electro-hydraulic servovalve to the actuator. The pressure value inside the TL has been controlled by the electro-hydraulic servovalve as a voltage supplied to the servovalve amplifier. The flow rate through the TL has been simulated by using the lumped π element electrical analogy method for laminar flow. The control voltage supplied to servovalve can be achieved by the direct using of the voltage function generator or indirect C++ program connected to the DAP-view program built in the DAP-card data acquisition connected to PC, to control the value of pressure in a selected point in the TL. It has been found that the relation between the voltage value and the output flow rate from the servovalve in most of the path is a linear relation. The MATLAB m-File program is used to create a representation state of the mathematical model to find a good simulation for the experimental open loop control test.
Optimal control of FES-assisted standing up in paraplegia using genetic algorithms.
Davoodi, R; Andrews, B J
1999-11-01
A practical system for Functional Electrical Stimulation (FES) assisted standing up in paraplegia should involve only a minimum of manual set up and tuning. An improved tuning method, using a genetic algorithm (GA) is proposed and demonstrated using computer simulation. Specifically, the GA adjusts the parameters of fuzzy logic (FL) and gain-scheduling proportional integral derivative (GS-PID) controllers that electrically stimulate the hip and knee musculature during the sit-stand maneuver. These new GA designed controllers were found to be effective in coordinating volitional and FES control according to formulated criteria. The latter was based on the deviations from a desired trajectory of the knee and hip joints and the magnitude of the voluntary upper body forces. The magnitude of the average arm forces were slightly higher when compared with the open-loop maximal stimulation of the hip and knee musculature; however, the terminal knee velocities were significantly reduced to less than 10 degrees /s. For practical implementation, the number of trials required to optimize the FL and GS-PID controllers can be reduced by a proposed pre-training procedure using a computer model scaled to the individual. The GA designed controllers remain near optimal provided the model-subject mismatch is small.
In Silico Magnetic Nanocontainers Navigation in Blood Vessels: A Feedback Control Approach.
Do, Ton Duc; Noh, Yeongil; Kim, Myeong Ok; Yoon, Jungwon
2016-06-01
Magnetic nanoparticles (MNPs) are recently used in a drug delivery system to pass the blood brain barrier. However, because the magnetic force acting on particles is proportional to their volumes, as the size of particles is small, the large magnetic field is required to produce enough magnetic force for overcoming the hydrodynamic drag force as well as other forces in blood vessels. Other difficulties for controlling MNPs are the complicated behavior of hydrodynamic drag force and uncertain factors in their dynamics. Therefore, open-loop control methods cannot guarantee guiding every MNP to the correct location. Considering these challenges, this paper introduces a feedback control approach for magnetic nanoparticles (MNPs) in blood vessels. To the best of our knowledge, this is the first time feedback controller that is designed for MNPs without aggregation. Simulation studies in MATLAB and real-time verifications on a physical model in COMSOL-MATLAB interface are performed to prove the feasibility of the proposed approach. It is shown that the proposed control scheme can accurately and effectively navigate the MNP to the correct path with feasible hardware supports.
Control design for the SISO system with the unknown order and the unknown relative degree.
Zhao, Chunzhe; Li, Donghai
2014-07-01
For the uncertain system whose order, relative degree and parameters are unknown in the control design, new research is still in need on the parameter tuning and close-loop stability. During the last 10 years, much progress is made in the application and theory research of the active disturbance rejection control (ADRC) for the uncertain system. In this study, the necessary and sufficient conditions are established for building the ADRC for the minimum-phase system and the open-loop stable system when the plant parameters, orders and relative degrees are unknown, the corresponding ideal dynamics are analyzed, and the theoretical results are verified by the simulations. Considering the wide application and the long history of the PID/PI controller, a method is given to design ADRC quickly based on the existing (generalized or conventional) PID/PI controller. A plenty of simulations are made to illustrate this PID/PI-based design method and the corresponding close-loop performances. The simulation examples include the minimum/nonminimum-phase plants, the stable/integrating plants, the high/low-order plant, and the plants with time delays. Such plants are from a wider scope than the theoretical result, and representative of many kinds of the industrial processes. That leads to a new way to simplify the ADRC design via absorbing the engineering experience in designing the PID/PI controller.
Multistrand, Fast Reaction, Shape Memory Alloy System for Uninhabited Aerial Vehicle Flight Control
Directory of Open Access Journals (Sweden)
M. Brennison
2012-01-01
Full Text Available This paper details an investigation of shape memory alloy (SMA filaments which are used to drive a flight control system with precision control in a real flight environment. An antagonistic SMA actuator was developed with an integrated demodulator circuit from a JR NES 911 subscale UAV actuator. Most SMA actuator studies concentrate on modeling the open-loop characteristics of such a system with full actuator performance modeling. This paper is a bit different in that it is very practically oriented and centered on development of a flight-capable system which solves the most tricky, practical problems associated with using SMA filaments for aircraft flight control. By using well-tuned feedback loops, it is shown that intermediate SMA performance prediction is not appropriate for flight control system (FCS design. Rather, capturing the peak behavior is far more important, along with appropriate feedback loop design. To prove the system, an SMA actuator was designed and installed in the fuselage of a 2 m uninhabited aerial vehicle (UAV and used to control the rudder through slips and coordinated turns. The actuator was capable of 20 degrees of positive and negative deflection and was capable of 7.5 in-oz (5.29 N cm of torque at a bandwidth of 2.8 Hz.
Self-optimising control for a class of continuous bioreactor via variable-structure feedback
Lara-Cisneros, Gerardo; Alvarez-Ramírez, José; Femat, Ricardo
2016-04-01
A self-optimising controller is designed for stabilisation of a class of bioreactor exploiting sliding-mode techniques. The stability analysis for the class of bioreactor, in open-loop configuration, suggests that the optimal behaviour, respect to maximal biomass production, occurs in an unstable region (structurally unstable). In this contribution, a variable-structure controller is designed, exploiting the inhibitory effect of substrate concentration under the biomass growth rate, such that the closed-loop system reaches the optimal manifold where the effect induced by the growth rate gradient is compensated (favouring the maximum growth rate). The self-optimising comprises an uncertainty estimator which computes the unknown terms for increasing the robustness issues of the sliding-mode scheme. Numerical experiments illustrate the performance and execution of the control strategy considering different parameter values for biomass growth rate. The robustness and fragility of the proposed controller are also discussed with respect to the modelling uncertainty and small changes in the controller gains, respectively.
A limit-cycle self-organizing map architecture for stable arm control.
Huang, Di-Wei; Gentili, Rodolphe J; Katz, Garrett E; Reggia, James A
2017-01-01
Inspired by the oscillatory nature of cerebral cortex activity, we recently proposed and studied self-organizing maps (SOMs) based on limit cycle neural activity in an attempt to improve the information efficiency and robustness of conventional single-node, single-pattern representations. Here we explore for the first time the use of limit cycle SOMs to build a neural architecture that controls a robotic arm by solving inverse kinematics in reach-and-hold tasks. This multi-map architecture integrates open-loop and closed-loop controls that learn to self-organize oscillatory neural representations and to harness non-fixed-point neural activity even for fixed-point arm reaching tasks. We show through computer simulations that our architecture generalizes well, achieves accurate, fast, and smooth arm movements, and is robust in the face of arm perturbations, map damage, and variations of internal timing parameters controlling the flow of activity. A robotic implementation is evaluated successfully without further training, demonstrating for the first time that limit cycle maps can control a physical robot arm. We conclude that architectures based on limit cycle maps can be organized to function effectively as neural controllers. Copyright © 2016 Elsevier Ltd. All rights reserved.
Active Control of 2/1 Magnetic Islands in the HBT-EP Tokamak
Energy Technology Data Exchange (ETDEWEB)
Navratil, G.A.; Cates, C.; Mauel, M.E.; Maurer, D.; Nadle, D.; Taylor, E.; Xiao, Q.; Wurden, G.A.; Reass, W.A.
1997-11-18
Closed and open loop control techniques were applied to growing m/n=2/1 rotating islands in wall stabilized plasmas in the HBT-EP tokamak. The approach taken by HBT-EP combines an adjustable segmented conducting wall (which slows the growth or stabilizes ideal external kinks) with a number of small (6{degree} wide) saddle coils located between the gaps of the conducting wall. In this paper we report demonstration of 2-phase island rotation control from 5 kHz to 15 kHz and observation of the phase instability which are well modeled by the single-helicity, predictions of nonlinear Rutherford island dynamics for 2/1 tearing modes including important effects of ion inertia and FLR which appears as a damping term in the model equations. The closed loop response of active feedback control of the 2/1 mode at moderate gain was observed to be in good agreement with the theory. We have also demonstrated suppression of the 2/1 island growth using an asynchronous frequency modulation drive which maintains the flow damping of the island by application of rotating control fields with frequencies alternating above and below the natural mode frequency. This frequency modulation control technique was also able to prevent disruptions normally observed to follow giant sawtooth crashes in the plasma core.
Multi-loop Control System Design for Biodiesel Process using Waste Cooking Oil
Patle, Dipesh S.; Z, Ahmad; Rangaiah, G. P.
2015-06-01
Biodiesel is one of the promising liquid fuels for future due to its advantages such as renewability and eco-friendliness. This manuscript describes the development of a multi-loop control system design for a comprehensive biodiesel process using waste cooking oil. Method for controlled variable-manipulated variable (CV-MV) pairings are vital for the stable, effective and economical operation of the process. Liquid recycles, product quality requirements and effective inventory control pose tough challenges to the safe operation of the biodiesel process. A simple and easy to apply effective RGA method [Xiong Q, Cai W J and He M J 2005 A practical loop pairing criterion for multivariable processes Journal of Process Control vol. 15 pp 741-747.] is applied to determine CV-MV pairings i.e. control configuration design for the bioprocess. This method uses steady state gain as well as bandwidth information of the process open loop transfer function to determine input-output pairings.
Directory of Open Access Journals (Sweden)
UMAIR SAEEDSOLANGI
2017-04-01
Full Text Available The problem of vehicular traffic congestion is a persistent constraint in the socio-economic development of Pakistan. This paper presents design and implementation of an intelligent traffic controller based on FPGA (Field Programmable Gate Array to provide an efficient traffic management by optimizing functioning of traffic lights which will result in minimizing traffic congestion at intersections. The existent Traffic Signal system in Pakistan is fixed-time based and offers only Open Loop method for Traffic Control. The Intelligent Traffic Controller presented here uses feedback sensors to read the Traffic density present at a four way intersection to provide an efficient alternative for better supervisory Control of Traffic flow. The traffic density based control logic has been developed in a State Flow Chart for improved visualization of State Machine based operation, and implemented as a Subsystem in Simulink and transferred into VHDL (Hardware Description Language code using HDL Coder for reducing development time and time to market, which are essential to capitalize Embedded Systems Market. The VHDL code is synthesized with Altera QUARTUS, simulated timing waveform is obtained to verify correctness of the algorithm for different Traffic Scenarios. For implementation purpose estimations were obtained for Cyclone-III and Stratix-III.
Closed-loop separation control over a sharp edge ramp using Genetic Programming
Debien, Antoine; Mazellier, Nicolas; Duriez, Thomas; Cordier, Laurent; Noack, Bernd R; Abel, Markus W; Kourta, Azeddine
2015-01-01
We experimentally perform open and closed-loop control of a separating turbulent boundary layer downstream from a sharp edge ramp. The turbulent boundary layer just above the separation point has a Reynolds number $Re_{\\theta}\\approx 3\\,500$ based on momentum thickness. The goal of the control is to mitigate separation and early re-attachment. The forcing employs a spanwise array of active vortex generators. The flow state is monitored with skin-friction sensors downstream of the actuators. The feedback control law is obtained using model-free genetic programming control (GPC) (Gautier et al. 2015). The resulting flow is assessed using the momentum coefficient, pressure distribution and skin friction over the ramp and stereo PIV. The PIV yields vector field statistics, e.g. shear layer growth, the backflow area and vortex region. GPC is benchmarked against the best periodic forcing. While open-loop control achieves separation reduction by locking-on the shedding mode, GPC gives rise to similar benefits by acc...
Directory of Open Access Journals (Sweden)
Wang Decheng
2015-01-01
Full Text Available The quartz lamp radiation aerodynamic heating simulation experiment system plays an important role on the structure strength heat experiment. In order to reduce its price and enhance flexibility on control law design of experiment system, a design method for low-cost quartz lamp radiation aerodynamic heating simulation experiment system with control law flexible adjustment feature is proposed. The hardware part is constructed by taking Digital Signal Processor (DSP as an implementing agency controller. The feedback temperature after processed is computed by DSP. But the experiment process control value is computed by computer. The feedback temperature and experiment process control value data are transferred by serial communication model between DSP and computer. The experiment process relation data is saved by computer with EXCEL file, including the given target spectrum, the feedback temperature and the control value. The results of experiments on system identification, PID spectrum tracking, different zone control and the open loop control show the effectiveness of the proposed method.
Hoadley, Sherwood T.; Mcgraw, Sandra M.
1992-01-01
A real time multiple-function digital controller system was developed for the Active Flexible Wing (AFW) Program. The digital controller system (DCS) allowed simultaneous execution of two control laws: flutter suppression and either roll trim or a rolling maneuver load control. The DCS operated within, but independently of, a slower host operating system environment, at regulated speeds up to 200 Hz. It also coordinated the acquisition, storage, and transfer of data for near real time controller performance evaluation and both open- and closed-loop plant estimation. It synchronized the operation of four different processing units, allowing flexibility in the number, form, functionality, and order of control laws, and variability in the selection of the sensors and actuators employed. Most importantly, the DCS allowed for the successful demonstration of active flutter suppression to conditions approximately 26 percent (in dynamic pressure) above the open-loop boundary in cases when the model was fixed in roll and up to 23 percent when it was free to roll. Aggressive roll maneuvers with load control were achieved above the flutter boundary. The purpose here is to present the development, validation, and wind tunnel testing of this multiple-function digital controller system.
FPGA-Based Implementation Direct Torque Control of Induction Motor
Directory of Open Access Journals (Sweden)
Saber Krim
2015-02-01
Full Text Available This paper proposes a digital implementation of the direct torque control (DTC of an Induction Motor (IM with an observation strategy on the Field Programmable Gate Array (FPGA. The hardware solution based on the FPGA is caracterised by fast processing speed due to the parallel processing. In this study the FPGA is used to overcome the limitation of the software solutions (Digital Signal Processor (DSP and Microcontroller. Also, the DTC of IM has many drawbacks such as for example; The open loop pure integration has from the problems of integration especially at the low speed and the variation of the stator resistance due to the temperature. To tackle these problems we use the Sliding Mode Observer (SMO. This observer is used estimate the stator flux, the stator current and the stator resistance. The hardware implementation method is based on Xilinx System Generator (XSG which a modeling tool developed by Xilinx for the design of implemented systems on FPGA; from the design of the DTC with SMO from XSG we can automatically generate the VHDL code. The model of the DTC with SMO has been designed and simulated using XSG blocks, synthesized with Xilinx ISE 12.4 tool and implemented on Xilinx Virtex-V FPGA.
Controlled locomotion of robots driven by a vibrating surface
Umbanhowar, Paul; Lynch, Kevin M.
Robots typically derive their powers of movement from onboard actuators and power sources, but other scenarios are possible where the external environment provides part or all of the necessary forcing and control. I will discuss details of a system where the ``robots'' are just planar solid objects and the requisite driving forces originate from frictional sliding-interactions with a periodically oscillated and nominally horizontal surface. For the robots to move, the temporal symmetry of the frictional forces must be broken, which is achieved here by modulating the normal force using vertical acceleration of the surface. Independent of the initial conditions and vibration waveform, a sliding locomotor reaches a unique velocity limit cycle at a given position. Its resulting motion can be described in terms of velocity fields which specify the robot's cycle-averaged velocity as a function of position. Velocity fields with non-zero spatial divergence can be generated by combining translational and rotational surface motions; this allows the simultaneous and open-loop collection, dispersal, and transport of multiple robots. Fields and field sequences can simultaneously move multiple robots between arbitrary positions and, potentially, along arbitrary trajectories. Supported by NSF CMMI #0700537.
Control to range for diabetes: functionality and modular architecture.
Kovatchev, Boris; Patek, Stephen; Dassau, Eyal; Doyle, Francis J; Magni, Lalo; De Nicolao, Giuseppe; Cobelli, Claudio
2009-09-01
Closed-loop control of type 1 diabetes is receiving increasing attention due to advancement in glucose sensor and insulin pump technology. Here the function and structure of a class of control algorithms designed to exert control to range, defined as insulin treatment optimizing glycemia within a predefined target range by preventing extreme glucose fluctuations, are studied. The main contribution of the article is definition of a modular architecture for control to range. Emphasis is on system specifications rather than algorithmic realization. The key system architecture elements are two interacting modules: range correction module, which assesses the risk for incipient hyper- or hypoglycemia and adjusts insulin rate accordingly, and safety supervision module, which assesses the risk for hypoglycemia and attenuates or discontinues insulin delivery when necessary. The novel engineering concept of range correction module is that algorithm action is relative to a nominal open-loop strategy-a predefined combination of basal rate and boluses believed to be optimal under nominal conditions. A proof of concept of the feasibility of our control-to-range strategy is illustrated by using a prototypal implementation tested in silico on patient use cases. These functional and architectural distinctions provide several advantages, including (i) significant insulin delivery corrections are only made if relevant risks are detected; (ii) drawbacks of integral action are avoided, e.g., undershoots with consequent hypoglycemic risks; (iii) a simple linear model is sufficient and complex algorithmic constraints are replaced by safety supervision; and (iv) the nominal profile provides straightforward individualization for each patient. We believe that the modular control-to-range system is the best approach to incremental development, regulatory approval, industrial deployment, and clinical acceptance of closed-loop control for diabetes. 2009 Diabetes Technology Society.
Hoadley, Sherwood T.; Mcgraw, Sandra M.
1992-01-01
A real-time multiple-function digital controller system was developed for the Active Flexible Wing (AFW) Program. The digital controller system (DCS) allowed simultaneous execution of two control laws: flutter suppression and either roll trim or a rolling maneuver load control. The DCS operated within, but independently of, a slower host operating system environment, at regulated speeds up to 200 Hz. It also coordinated the acquisition, storage, and transfer of data for near real-time controller performance evaluation and both open- and closed-loop plant estimation. It synchronized the operation of four different processing units, allowing flexibility in the number, form, functionality, and order of control laws, and variability in selection of sensors and actuators employed. Most importantly, the DCS allowed for the successful demonstration of active flutter suppression to conditions approximately 26 percent (in dynamic pressure) above the open-loop boundary in cases when the model was fixed in roll and up to 23 percent when it was free to roll. Aggressive roll maneuvers with load control were achieved above the flutter boundary.
Balance control and anti-gravity muscle activity during the experience of fear at heights.
Wuehr, Max; Kugler, Guenter; Schniepp, Roman; Eckl, Maria; Pradhan, Cauchy; Jahn, Klaus; Huppert, Doreen; Brandt, Thomas
2014-02-01
Fear of heights occurs when a visual stimulus causes the apprehension of losing balance and falling. A moderate form of visual height intolerance (vHI) affects about one third of the general population and has relevant consequences for the quality of life. A quantitative evaluation of balance mechanisms in persons susceptible to vHI during height exposure is missing. VHI-related changes in postural control were assessed by center-of-pressure displacements and electromyographic recordings of selected leg, arm, and neck muscles in 16 subjects with vHI while standing at heights on an emergency balcony versus standing in the laboratory at ground level. Characteristics of open- and closed-loop postural control were analyzed. Body sway and muscle activity parameters were correlated with the subjective estimates of fear at heights. During height exposure, (1) open-loop control was disturbed by a higher diffusion activity (P change occurs in (1) open- and closed-loop postural control strategy and (2) co-contraction of anti-gravity leg and neck muscles, both of which depend on the severity of evoked fear at heights.
Directory of Open Access Journals (Sweden)
Behnam Dadashzadeh
2013-09-01
Full Text Available This paper investigates two fundamental structures for biped robots and a control strategy to achieve stable biped running. The first biped structure contains straight legs with telescopic springs, and the second one contains knees with compliant elements in parallel with the motors. With both configurations we can use a standard linear discrete-time state-feedback control strategy to achieve an active periodic stable biped running gait, using the Poincare map of one complete step to produce the discrete-time model. In this case, the Poincare map describes an open-loop system with an unstable equilibrium, requiring a closed- loop control for stabilization. The discretization contains a stance phase, a flight phase and a touch-down. In the first approach, the control signals remain constant during each phase, while in the second approach both phases are discretized into a number of constant-torque intervals, so that its formulation can be applied easily to stabilize any active biped running gait. Simulation results with both the straight-legged and the kneed biped model demonstrate stable gaits on both horizontal and inclined surfaces.
Reduction of Helicopter BVI Noise, Vibration, and Power Consumption Through Individual Blade Control
Jacklin, Stephen A.; Blaas, Achim; Teves, Dietrich; Kube, Roland; Warmbrodt, William (Technical Monitor)
1994-01-01
A wind tunnel test was conducted with a full-scale BO 105 helicopter rotor to evaluate the potential of open-loop individual blade control (IBC) to improve rotor performance, to reduce blade vortex interaction (BVI) noise, and to alleviate helicopter vibrations. The wind tunnel test was an international collaborative effort between NASA/U.S. Army AFDD, ZF Luftfahrttechnik, Eurocopter Deutschland, and the German Aerospace Laboratory (DLR) and was conducted under the auspices of the U.S./German MOU on Rotorcraft Aeromechanics. In this test the normal blade pitch links of the rotor were replaced by servo-actuators so that the pitch of each blade could be controlled independently of the other blades. The specially designed servoactuators and IBC control system were designed and manufactured by ZF Luftfahrttechnik, GmbH. The wind tunnel test was conducted in the 40- by 80-Foot Wind Tunnel at the NASA Ames Research Center. An extensive amount of measurement information was acquired for each IBC data point. These data include rotor performance, static and dynamic hub forces and moments, rotor loads, control loads, inboard and outboard blade pitch motion, and BVI noise data. The data indicated very significant (80 percent) simultaneous reductions in both BVI noise and hub vibrations could be obtained using multi-harmonic input at the critical descent (terminal approach) condition. The data also showed that performance improvements of up to 7 percent could be obtained using 2P input at high-speed forward flight conditions.
A Survey of Insulin-Dependent Diabetes—Part II: Control Methods
Directory of Open Access Journals (Sweden)
Daisuke Takahashi
2008-01-01
Full Text Available We survey blood glucose control schemes for insulin-dependent diabetes therapies and systems. These schemes largely rely on mathematical models of the insulin-glucose relations, and these models are typically derived in an empirical or fundamental way. In an empirical way, the experimental insulin inputs and resulting blood-glucose outputs are used to generate a mathematical model, which includes a couple of equations approximating a very complex system. On the other hand, the insulin-glucose relation is also explained from the well-known facts of other biological mechanisms. Since these mechanisms are more or less related with each other, a mathematical model of the insulin-glucose system can be derived from these surrounding relations. This kind of method of the mathematical model derivation is called a fundamental method. Along with several mathematical models, researchers develop autonomous systems whether they involve medical devices or not to compensate metabolic disorders and these autonomous systems employ their own control methods. Basically, in insulin-dependent diabetes therapies, control methods are classified into three categories: open-loop, closed-loop, and partially closed-loop controls. The main difference among these methods is how much the systems are open to the outside people.
Directory of Open Access Journals (Sweden)
Rauh Andreas
2016-03-01
Full Text Available In this paper, control-oriented modeling approaches are presented for distributed parameter systems. These systems, which are in the focus of this contribution, are assumed to be described by suitable partial differential equations. They arise naturally during the modeling of dynamic heat transfer processes. The presented approaches aim at developing finite-dimensional system descriptions for the design of various open-loop, closed-loop, and optimal control strategies as well as state, disturbance, and parameter estimation techniques. Here, the modeling is based on the method of integrodifferential relations, which can be employed to determine accurate, finite-dimensional sets of state equations by using projection techniques. These lead to a finite element representation of the distributed parameter system. Where applicable, these finite element models are combined with finite volume representations to describe storage variables that are—with good accuracy—homogeneous over sufficiently large space domains. The advantage of this combination is keeping the computational complexity as low as possible. Under these prerequisites, real-time applicable control algorithms are derived and validated via simulation and experiment for a laboratory-scale heat transfer system at the Chair of Mechatronics at the University of Rostock. This benchmark system consists of a metallic rod that is equipped with a finite number of Peltier elements which are used either as distributed control inputs, allowing active cooling and heating, or as spatially distributed disturbance inputs.
Modeling of Step-up Grid-Connected Photovoltaic Systems for Control Purposes
Directory of Open Access Journals (Sweden)
Daniel Gonzalez
2012-06-01
Full Text Available This paper presents modeling approaches for step-up grid-connected photovoltaic systems intended to provide analytical tools for control design. The first approach is based on a voltage source representation of the bulk capacitor interacting with the grid-connected inverter, which is a common model for large DC buses and closed-loop inverters. The second approach considers the inverter of a double-stage PV system as a Norton equivalent, which is widely accepted for open-loop inverters. In addition, the paper considers both ideal and realistic models for the DC/DC converter that interacts with the PV module, providing four mathematical models to cover a wide range of applications. The models are expressed in state space representation to simplify its use in analysis and control design, and also to be easily implemented in simulation software, e.g., Matlab. The PV system was analyzed to demonstrate the non-minimum phase condition for all the models, which is an important aspect to select the control technique. Moreover, the system observability and controllability were studied to define design criteria. Finally, the analytical results are illustrated by means of detailed simulations, and the paper results are validated in an experimental test bench.
Reduction of Helicopter BVI Noise, Vibration, and Power Consumption Through Individual Blade Control
Jacklin, Stephen A.; Blaas, Achim; Teves, Dietrich; Kube, Roland; Warmbrodt, William (Technical Monitor)
1994-01-01
A wind tunnel test was conducted with a full-scale BO 105 helicopter rotor to evaluate the potential of open-loop individual blade control (IBC) to improve rotor performance, to reduce blade vortex interaction (BVI) noise, and to alleviate helicopter vibrations. The wind tunnel test was an international collaborative effort between NASA/U.S. Army AFDD, ZF Luftfahrttechnik, Eurocopter Deutschland, and the German Aerospace Laboratory (DLR) and was conducted under the auspices of the U.S./German MOU on Rotorcraft Aeromechanics. In this test the normal blade pitch links of the rotor were replaced by servo-actuators so that the pitch of each blade could be controlled independently of the other blades. The specially designed servoactuators and IBC control system were designed and manufactured by ZF Luftfahrttechnik, GmbH. The wind tunnel test was conducted in the 40- by 80-Foot Wind Tunnel at the NASA Ames Research Center. An extensive amount of measurement information was acquired for each IBC data point. These data include rotor performance, static and dynamic hub forces and moments, rotor loads, control loads, inboard and outboard blade pitch motion, and BVI noise data. The data indicated very significant (80 percent) simultaneous reductions in both BVI noise and hub vibrations could be obtained using multi-harmonic input at the critical descent (terminal approach) condition. The data also showed that performance improvements of up to 7 percent could be obtained using 2P input at high-speed forward flight conditions.
Closed-loop control of zebrafish response using a bioinspired robotic-fish in a preference test.
Kopman, Vladislav; Laut, Jeffrey; Polverino, Giovanni; Porfiri, Maurizio
2013-01-06
In this paper, we study the response of zebrafish to a robotic-fish whose morphology and colour pattern are inspired by zebrafish. Experiments are conducted in a three-chambered instrumented water tank where a robotic-fish is juxtaposed with an empty compartment, and the preference of live subjects is scored as the mean time spent in the vicinity of the tank's two lateral sides. The tail-beating of the robotic-fish is controlled in real-time based on feedback from fish motion to explore a spectrum of closed-loop systems, including proportional and integral controllers. Closed-loop control systems are complemented by open-loop strategies, wherein the tail-beat of the robotic-fish is independent of the fish motion. The preference space and the locomotory patterns of fish for each experimental condition are analysed and compared to understand the influence of real-time closed-loop control on zebrafish response. The results of this study show that zebrafish respond differently to the pattern of tail-beating motion executed by the robotic-fish. Specifically, the preference and behaviour of zebrafish depend on whether the robotic-fish tail-beating frequency is controlled as a function of fish motion and how such closed-loop control is implemented.
Geng, Chao; Luo, Wen; Tan, Yi; Liu, Hongmei; Mu, Jinbo; Li, Xinyang
2013-10-21
A novel approach of tip/tilt control by using divergence cost function in stochastic parallel gradient descent (SPGD) algorithm for coherent beam combining (CBC) is proposed and demonstrated experimentally in a seven-channel 2-W fiber amplifier array with both phase-locking and tip/tilt control, for the first time to our best knowledge. Compared with the conventional power-in-the-bucket (PIB) cost function for SPGD optimization, the tip/tilt control using divergence cost function ensures wider correction range, automatic switching control of program, and freedom of camera's intensity-saturation. Homemade piezoelectric-ring phase-modulator (PZT PM) and adaptive fiber-optics collimator (AFOC) are developed to correct piston- and tip/tilt-type aberrations, respectively. The PIB cost function is employed for phase-locking via maximization of SPGD optimization, while the divergence cost function is used for tip/tilt control via minimization. An average of 432-μrad of divergence metrics in open loop has decreased to 89-μrad when tip/tilt control implemented. In CBC, the power in the full width at half maximum (FWHM) of the main lobe increases by 32 times, and the phase residual error is less than λ/15.
Directory of Open Access Journals (Sweden)
M. Annamalai
2012-01-01
Full Text Available The aim of this study is to simulate and implement open loop and closed loop controlled DC-DC converter for stand-alone wind energy system. Wind turbines, however, are not always very efficient in the wind speeds that are most common to a region. Typically, wind energy systems are designed to be highly efficient in high wind speed and have a cut-off wind speed- below which no energy is captured. In remote locations where wind energy is used for battery charging, the energy lost below the cut-off wind speed could be used for trickle charging or maintaining a batteryâs fully charged state. Wind turbines are most efficient when they are operated at one specific Tip-Speed to Wind-Speed Ratio (TSR. Therefore, for the efficient capture of wind power, turbine speed should be controlled to follow the ideal TSR, with an optimal operating point, which is different for every wind speed In this system, the DC-DC converter in the DC link with a constant dc voltage to the load, a DC-DC converter will allow the voltage at the output of a diode bridge rectifier to be controlled. In low wind speed conditions, the voltage may be lowered to prevent the dc link from reverse biasing the diode rectifier. Under high wind speed condition, the voltage may be increased, reducing I2R losses. In addition, adjusting the voltage on the dc rectifier will change the generator terminal voltage and thereby provide control over the current flowing out of the generator. The LCL-T resonant inverter system for both open loop and closed loop DC-to-DC converter systems are simulated using MATLAB simulink power system blocks. This converter has advantages like reduced transformer size, reduced filter size and current source characteristics. The simulation studies indicate that LCL-T type for open and closed loop DC-DC converter can be used with stand-alone wind generator. Constant voltage can be maintained at the output of DC-to-DC converter by using a PWM rectifier at the output
Optimal control of batch emulsion polymerization of vinyl chloride
Energy Technology Data Exchange (ETDEWEB)
Damslora, Andre Johan
1998-12-31
The highly exothermic polymerization of vinyl chloride (VC) is carried out in large vessels where the heat removal represents a major limitation of the production rate. Many emulsion polymerization reactors are operated in such a way that a substantial part of the heat transfer capacity is left unused for a significant part of the total batch time. To increase the reaction rate so that it matches the heat removal capacity during the course of the reaction, this thesis proposes the use of a sufficiently flexible initiator system to obtain a reaction rate which is high throughout the reaction and real-time optimization to compute the addition policy for the initiator. This optimization based approach provides a basis for an interplay between design and control and between production and research. A simple model is developed for predicting the polymerization rate. The model is highly nonlinear and open-loop unstable and may serve as an interesting case for comparison of nonlinear control strategies. The model is fitted to data obtained in a laboratory scale reactor. Finally, the thesis discusses optimal control of the emulsion polymerization reactor. Reduction of the batch cycle time is of major economic importance, as long as the quality parameters are within their specifications. The control parameterization had a major influence on the performance. A differentiable spline parameterization was applied and the optimization is illustrated in a number of cases. The best performance is obtained when the reactor temperature is obtained when the optimization is combined with some form of closed-loop control of the reactor temperature. 112 refs., 48 figs., 4 tabs.
Reddy, Monika; Herrero, Pau; Sharkawy, Mohamed El; Pesl, Peter; Jugnee, Narvada; Pavitt, Darrell; Godsland, Ian F; Alberti, George; Toumazou, Christofer; Johnston, Desmond G; Georgiou, Pantelis; Oliver, Nick S
2015-11-17
The Bio-inspired Artificial Pancreas (BiAP) is a closed-loop insulin delivery system based on a mathematical model of beta-cell physiology and implemented in a microchip within a low-powered handheld device. We aimed to evaluate the safety and efficacy of the BiAP over 24 hours, followed by a substudy assessing the safety of the algorithm without and with partial meal announcement. Changes in lactate and 3-hydroxybutyrate concentrations were investigated for the first time during closed-loop. This is a prospective randomized controlled open-label crossover study. Participants were randomly assigned to attend either a 24-hour closed-loop visit connected to the BiAP system or a 24-hour open-loop visit (standard insulin pump therapy). The primary outcome was percentage time spent in target range (3.9-10 mmol/l) measured by sensor glucose. Secondary outcomes included percentage time in hypoglycemia (10 mmol/l). Participants were invited to attend for an additional visit to assess the BiAP without and with partial meal announcements. A total of 12 adults with type 1 diabetes completed the study (58% female, mean [SD] age 45 [10] years, BMI 25 [4] kg/m(2), duration of diabetes 22 [12] years and HbA1c 7.4 [0.7]% [58 (8) mmol/mol]). The median (IQR) percentage time in target did not differ between closed-loop and open-loop (71% vs 66.9%, P = .9). Closed-loop reduced time spent in hypoglycemia from 17.9% to 3.0% (P time was spent in hyperglycemia (10% vs 28.9%, P = .01). The percentage time in target was higher when all meals were announced during closed-loop compared to no or partial meal announcement (65.7% [53.6-80.5] vs 45.5% [38.2-68.3], P = .12). The BiAP is safe and achieved equivalent time in target as measured by sensor glucose, with improvement in hypoglycemia, when compared to standard pump therapy. © 2015 Diabetes Technology Society.
OPTICON: Pro-Matlab software for large order controlled structure design
Peterson, Lee D.
1989-01-01
A software package for large order controlled structure design is described and demonstrated. The primary program, called OPTICAN, uses both Pro-Matlab M-file routines and selected compiled FORTRAN routines linked into the Pro-Matlab structure. The program accepts structural model information in the form of state-space matrices and performs three basic design functions on the model: (1) open loop analyses; (2) closed loop reduced order controller synthesis; and (3) closed loop stability and performance assessment. The current controller synthesis methods which were implemented in this software are based on the Generalized Linear Quadratic Gaussian theory of Bernstein. In particular, a reduced order Optimal Projection synthesis algorithm based on a homotopy solution method was successfully applied to an experimental truss structure using a 58-state dynamic model. These results are presented and discussed. Current plans to expand the practical size of the design model to several hundred states and the intention to interface Pro-Matlab to a supercomputing environment are discussed.
Modelling and control of a tokamak plasma; Modelisation et commande d`un plasma de tokamak
Energy Technology Data Exchange (ETDEWEB)
Bremond, S.
1995-10-18
Vertically elongated tokamak plasmas, while attractive as regards Lawson criteria, are intrinsically instable. It is found that the open-loop instability dynamics is characterised by the relative value of two dimensionless parameters: the coefficient of inductive coupling between the vessel and the coils, and the coil damping efficiency on the plasma displacement relative to that of the vessel. Applications to Tore Supra -where the instability is due to the iron core attraction- and DIII-D are given. A counter-effect of the vessel, which temporarily reverses the effect of coil control on the plasma displacement, is seen when the inductive coupling is higher than the damping ratio. Precise control of the plasma boundary is necessary if plasma-wall interaction and/or coupling to heating antennas are to be monitored. A positional drift, of a few mm/s, which had been observed in the Tore Supra tokamak, is explained and corrected. A linear plasma shape response model is then derived from magnetohydrodynamic equilibrium calculation, and proved to be in good agreement with experimental data. An optimal control law is derived, which minimizes an integral quadratic criteria on tracking errors and energy expenditure. This scheme avoids compensating coil currents, and could render local plasma shaping more precise. (authors). 123 refs., 77 figs., 6 tabs., 4 annexes.
Path Planning of Mobile Elastic Robotic Arms by Indirect Approach of Optimal Control
Directory of Open Access Journals (Sweden)
Moharam Habibnejad Korayem
2011-03-01
Full Text Available Finding optimal trajectory is critical in several applications of robot manipulators. This paper is applied the open-loop optimal control approach for generating the optimal trajectory of the flexible mobile manipulators in point-to-point motion. This method is based on the Pontryagin-s minimum principle that by providing a two-point boundary value problem is solved the problem. This problem is known to be complex in particular when combined motion of the base and manipulator, non-holonomic constraint of the base and highly non-linear and complicated dynamic equations as a result of flexible nature of links are taken into account. The study emphasizes on modeling of the complete optimal control problem by remaining all nonlinear state and costate variables as well as control constraints. In this method, designer can compromise between different objectives by considering the proper penalty matrices and it yields to choose the proper trajectory among the various paths. The effectiveness and capability of the proposed approach are demonstrated through simulation studies. Finally, to verify the proposed method, the simulation results obtained from the model are compared with the results of those available in the literature.
An Intelligent Control Method for Thyristors%晶闸管的智能化控制
Institute of Scientific and Technical Information of China (English)
胡玉祥
2000-01-01
提出一种由单片机实现的晶闸管智能化控制方法，这种方法能够对晶闸管导通角进行检测，改变了以往晶闸管导通角开环控制的方式，实现了晶闸管导通角的闭环控制，并且各种保护功能齐备，可以达到晶闸管的安全可靠高效地运行。%In this paper, an intelligent control method using single-chip microcomputer for thyristors is introduced. This method performs closed-loop control for oonducting angle of thyristors by detecting terminal voltage of thyristors, and replaces opened-loop control method which was widely used in the past. This method has also several protective functions, therefore thyristors operate safely, reliably and efficiently.
Simulink-Based Simulation Architecture for Evaluating Controls for Aerospace Vehicles (SAREC-ASV)
Christhilf, David m.; Bacon, Barton J.
2006-01-01
The Simulation Architecture for Evaluating Controls for Aerospace Vehicles (SAREC-ASV) is a Simulink-based approach to providing an engineering quality desktop simulation capability for finding trim solutions, extracting linear models for vehicle analysis and control law development, and generating open-loop and closed-loop time history responses for control system evaluation. It represents a useful level of maturity rather than a finished product. The layout is hierarchical and supports concurrent component development and validation, with support from the Concurrent Versions System (CVS) software management tool. Real Time Workshop (RTW) is used to generate pre-compiled code for substantial component modules, and templates permit switching seamlessly between original Simulink and code compiled for various platforms. Two previous limitations are addressed. Turn around time for incorporating tabular model components was improved through auto-generation of required Simulink diagrams based on data received in XML format. The layout was modified to exploit a Simulink "compile once, evaluate multiple times" capability for zero elapsed time for use in trimming and linearizing. Trim is achieved through a Graphical User Interface (GUI) with a narrow, script definable interface to the vehicle model which facilitates incorporating new models.
DSP-based control of a high frequency three cell flying capacitor inverter
Flores-Fuentes, A. A.; Rossano-Díaz, I. O.; Peña-Eguiluz, R.; López-Callejas, R.; Mercado-Cabrera, A.; de la Piedad-Beneitez, A.; Barocio, S. R.; Valencia, R.
2010-03-01
The design, instrumentation and early operation results of a digitally controlled voltage source inverter (VSI) are described. This inverter has been structured from a three cell flying capacitor inverter (TCFCI). Two different inverter control modes - open-loop and closed-loop - are applied by a digital system based on a Texas Instrument TMS320C6713 digital signal processor (DSP) board. The VSI is able to generate AC voltage signals up to 120 V amplitudes at a maximal 6 A current, from ∼9 kHz to ∼60 kHz in ∼900 Hz steps in both controls by varying the signal period through the square-wave command strategy. The multi-cell structure of the inverter provides an output frequency nearly three times that of the TCFCI semiconductor commutation. The power output of the TCFCI can drive a high frequency step-up transformer which, in turn, is associated with a cylindrical reactor where dielectric barrier discharges (DBD) are conducted.
OPTICON: Pro-Matlab software for large order controlled structure design
Peterson, Lee D.
1989-01-01
A software package for large order controlled structure design is described and demonstrated. The primary program, called OPTICAN, uses both Pro-Matlab M-file routines and selected compiled FORTRAN routines linked into the Pro-Matlab structure. The program accepts structural model information in the form of state-space matrices and performs three basic design functions on the model: (1) open loop analyses; (2) closed loop reduced order controller synthesis; and (3) closed loop stability and performance assessment. The current controller synthesis methods which were implemented in this software are based on the Generalized Linear Quadratic Gaussian theory of Bernstein. In particular, a reduced order Optimal Projection synthesis algorithm based on a homotopy solution method was successfully applied to an experimental truss structure using a 58-state dynamic model. These results are presented and discussed. Current plans to expand the practical size of the design model to several hundred states and the intention to interface Pro-Matlab to a supercomputing environment are discussed.
Compliance and control characteristics of an additive manufactured-flexure stage
Energy Technology Data Exchange (ETDEWEB)
Lee, ChaBum; Tarbutton, Joshua A. [Department of Mechanical Engineering, University of South Carolina, 300 Main St., Columbia, South Carolina 29208 (United States)
2015-04-15
This paper presents a compliance and positioning control characteristics of additive manufactured-nanopositioning system consisted of the flexure mechanism and voice coil motor (VCM). The double compound notch type flexure stage was designed to utilize the elastic deformation of two symmetrical four-bar mechanisms to provide a millimeter-level working range. Additive manufacturing (AM) process, stereolithography, was used to fabricate the flexure stage. The AM stage was inspected by using 3D X-ray computerized tomography scanner: air-voids and shape irregularity. The compliance, open-loop resonance peak, and damping ratio of the AM stage were measured 0.317 mm/N, 80 Hz, and 0.19, respectively. The AM stage was proportional-integral-derivative positioning feedback-controlled and the capacitive type sensor was used to measure the displacement. As a result, the AM flexure mechanism was successfully 25 nm positioning controlled within 500 μm range. The resonance peak was found approximately at 280 Hz in closed-loop. This research showed that the AM flexure mechanism and the VCM can provide millimeter range with high precision and can be a good alternative to an expensive metal-based flexure mechanism and piezoelectric transducer.
Institute of Scientific and Technical Information of China (English)
李艳杰; 崔天宇; 王海; 马鹤; 苗鑫超
2013-01-01
A software implementation method of hydraulic cylinder position PID closed loop control in proportional valve control system using Siemens S7-200 was proposed.The block diagram and ladder program was given,and experimental studies in Festo TP701 proportional hydraulic test bed was done.Experimental studies have shown that the proportion of open-loop control system,using software methods can achieve the closed-loop control of position and other physical quantities,to control the performance of precision and anti-jamming capability to meet the demand of general industrial applications.%提出一种利用西门子S7-200实现比例阀控制系统中液压缸位置PID闭环控制的软件实现方法,给出了程序框图及梯形图程序,并在Festo TP701比例液压试验台上进行实验研究.实验研究表明,开环比例控制系统中,利用软件的方法可实现位置等物理量的闭环控制,控制精度和抗干扰能力等性能可满足一般工业应用的需求.
Gong, Jian; Kim, Chang-Jin C J
2008-06-01
Electrowetting-on-dielectric (EWOD) actuation enables digital (or droplet) microfluidics where small packets of liquids are manipulated on a two-dimensional surface. Due to its mechanical simplicity and low energy consumption, EWOD holds particular promise for portable systems. To improve volume precision of the droplets, which is desired for quantitative applications such as biochemical assays, existing practices would require near-perfect device fabrication and operation conditions unless the droplets are generated under feedback control by an extra pump setup off of the chip. In this paper, we develop an all-electronic (i.e., no ancillary pumping) real-time feedback control of on-chip droplet generation. A fast voltage modulation, capacitance sensing, and discrete-time PID feedback controller are integrated on the operating electronic board. A significant improvement is obtained in the droplet volume uniformity, compared with an open loop control as well as the previous feedback control employing an external pump. Furthermore, this new capability empowers users to prescribe the droplet volume even below the previously considered minimum, allowing, for example, 1 : x (x < 1) mixing, in comparison to the previously considered n : m mixing (i.e., n and m unit droplets).
Gong, Jian; Kim, Chang-Jin “CJ”
2009-01-01
Electrowetting-on-dielectric (EWOD) actuation enables digital (or droplet) microfluidics where small packets of liquids are manipulated on a two-dimensional surface. Due to its mechanical simplicity and low energy consumption, EWOD holds particular promise for portable systems. To improve volume precision of the droplets, which is desired for quantitative applications such as biochemical assays, existing practices would require near-perfect device fabricaion and operation conditions unless the droplets are generated under feedback control by an extra pump setup off of the chip. In this paper, we develop an all-electronic (i.e., no ancillary pumping) real-time feedback control of on-chip droplet generation. A fast voltage modulation, capacitance sensing, and discrete-time PID feedback controller are integrated on the operating electronic board. A significant improvement is obtained in the droplet volume uniformity, compared with an open loop control as well as the previous feedback control employing an external pump. Furthermore, this new capability empowers users to prescribe the droplet volume even below the previously considered minimum, allowing, for example, 1:x (x < 1) mixing, in comparison to the previously considered n:m mixing (i.e., n and m unit droplets). PMID:18497909
Gorzelic, P.; Schiff, S. J.; Sinha, A.
2013-04-01
Objective. To explore the use of classical feedback control methods to achieve an improved deep brain stimulation (DBS) algorithm for application to Parkinson's disease (PD). Approach. A computational model of PD dynamics was employed to develop model-based rational feedback controller design. The restoration of thalamocortical relay capabilities to patients suffering from PD is formulated as a feedback control problem with the DBS waveform serving as the control input. Two high-level control strategies are tested: one that is driven by an online estimate of thalamic reliability, and another that acts to eliminate substantial decreases in the inhibition from the globus pallidus interna (GPi) to the thalamus. Control laws inspired by traditional proportional-integral-derivative (PID) methodology are prescribed for each strategy and simulated on this computational model of the basal ganglia network. Main Results. For control based upon thalamic reliability, a strategy of frequency proportional control with proportional bias delivered the optimal control achieved for a given energy expenditure. In comparison, control based upon synaptic inhibitory output from the GPi performed very well in comparison with those of reliability-based control, with considerable further reduction in energy expenditure relative to that of open-loop DBS. The best controller performance was amplitude proportional with derivative control and integral bias, which is full PID control. We demonstrated how optimizing the three components of PID control is feasible in this setting, although the complexity of these optimization functions argues for adaptive methods in implementation. Significance. Our findings point to the potential value of model-based rational design of feedback controllers for Parkinson's disease.
Feedback control system of the mechanical arm based on STM32%基于STM32的机械臂反馈控制系统
Institute of Scientific and Technical Information of China (English)
查帅荣; 周海芳; 章杰
2014-01-01
为了解决机械臂开环控制精度低的问题，设计了一套基于 STM32微控制器的机械臂反馈控制系统。通过 QT 图形界面将控制数据输入上位机，控制数据经串口传输到微控制器后驱动机械臂运动；由加速度传感器和磁通传感器组成的惯性传感器节点采集机械臂运动数据传回微控制器，采用由多个相关的参数可变 PID 控制器构成的控制器组对机械臂各个部位进行反馈控制。测试结果表明，利用惯性传感器实现的改进型 PID 的反馈控制系统比无反馈控制系统精度有较大提高，可用于实现更高精度的机械臂控制。%The open loop mechanical arm control system has low accuracy, so a feedback control system on the STM32 for the mechanical arm is designed and implemented in this paper. The data of arm control is entered with QT graphic interfaces and transmitted to the embedded system through serial port to drive the steering engine. The system uses sensor nodes , which contain accelerometer, gyroscope and magnetic sensor, to collect motion data of the arm and transmit to the embedded system. An improved PID controller system with variable parameters is used to control different parts of the mechanical arm. The experimental tests show that the control accuracy of the feedback control system is significantly improved compared with the open loop system.
Directory of Open Access Journals (Sweden)
Mustapha MESSAOUDI
2008-06-01
Full Text Available In this paper, the classical Direct Torque Control (DTC of Induction Motor (IM using an open loop pure integration suffers from the well-known problems of integration especially in the low speed operation range is detailed. To tackle this problem, the IM variables and parameters estimation is performed using a recursive non-linear observer known as EKF. This observer is used to estimate the stator currents, the rotor flux linkages, the rotor speed and the stator resistance. The main drawback of the EKF in this case is that the load dynamics has to be known which is not usually possible. Therefore, a new method based on the Model Reference Adaptive System (MRAS is used to estimate the rotor speed. The two different nonlinear observers applied to sensorless DTC of IM, are discussed and compared to each other. The rotor speed estimation in DTC technique is affected by parameter variations especially the stator resistance due to temperature particularly at low speeds. Therefore, it is necessary to compensate this parameter variation in sensorless induction motor drives using an online adaptation of the control algorithm by the estimated stator resistance. A simulation work leads to the selected results to support the study findings.