Journal articles: 'Closed loop delay compensation'

1

Qi, Kai, and J. S. Kuang. "Time delay compensation in active closed-loop structural control." Mechanics Research Communications 22, no. 2 (March 1995): 129–35. http://dx.doi.org/10.1016/0093-6413(95)00005-4.

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Molina-Cabrera, Alexander, Mario A. Ríos, Yvon Besanger, Nouredine Hadjsaid, and Oscar Danilo Montoya. "Latencies in Power Systems: A Database-Based Time-Delay Compensation for Memory Controllers." Electronics 10, no. 2 (January 18, 2021): 208. http://dx.doi.org/10.3390/electronics10020208.

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Time-delay is inherent to communications schemes in power systems, and in a closed loop strategy the presence of latencies increases inter-area oscillations and security problems in tie-lines. Recently, Wide Area Measurement Systems (WAMS) have been introduced to improve observability and overcome slow-rate communications from traditional Supervisory Control and Data Acquisition (SCADA). However, there is a need for tackling time-delays in control strategies based in WAMS. For this purpose, this paper proposes an Enhanced Time Delay Compensator (ETDC) approach which manages varying time delays introducing the perspective of network latency instead dead time; also, ETDC takes advantage of real signals and measurements transmission procedure in WAMS building a closed-loop memory control for power systems. The strength of the proposal was tested satisfactorily in a widely studied benchmark model in which inter-area oscillations were excited properly.

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Liu, Muyang, Ioannis Dassios, Georgios Tzounas, and Federico Milano. "Model-Independent Derivative Control Delay Compensation Methods for Power Systems." Energies 13, no. 2 (January 10, 2020): 342. http://dx.doi.org/10.3390/en13020342.

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The paper examines the effectiveness of utilizing the derivatives of time delayed, wide-area signals in mitigating their destabilizing impact on power system dynamic response. In particular, the paper discusses two derivative control-based delay compensation methods, namely proportional-derivative (PD) and predictor-based delay compensation. The two methods are compared in terms of their open-loop signal fidelity and their impact on the closed-loop system stability. The paper also provides a technique to carry out small-signal stability analysis with inclusion of derivative control based compensation, which leads to a Neutral Time-Delay System (NTDS). In addition, we provide a new theorem on the stability of the NTDS. Finally, nonlinear time domain simulations and eigenvalue analysis based on the IEEE 14-bus and New England 39-bus systems were carried out for the sake of comparison of the two delay compensation methods.

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Reboldi, G. P., P. D. Home, G. Calabrese, P. G. Fabietti, P. Brunetti, and M. Massi Benedetti. "Time Delay Compensation for Closed-Loop Insulin Delivery Systems: A Simulation Study." International Journal of Artificial Organs 14, no. 6 (June 1991): 350–58. http://dx.doi.org/10.1177/039139889101400606.

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Zheng, Yingshi, Mark J. Brudnak, Paramsothy Jayakumar, Jeffrey L. Stein, and Tulga Ersal. "A Predictor-Based Framework for Delay Compensation in Networked Closed-Loop Systems." IEEE/ASME Transactions on Mechatronics 23, no. 5 (October 2018): 2482–93. http://dx.doi.org/10.1109/tmech.2018.2864722.

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Ellis, Matthew, and Panagiotis D. Christofides. "Economic model predictive control of nonlinear time-delay systems: Closed-loop stability and delay compensation." AIChE Journal 61, no. 12 (August 3, 2015): 4152–65. http://dx.doi.org/10.1002/aic.14964.

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Liu, Zhang, and Zou. "Robust LFC Strategy for Wind Integrated Time-Delay Power System Using EID Compensation." Energies 12, no. 17 (August 21, 2019): 3223. http://dx.doi.org/10.3390/en12173223.

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This paper presents an active disturbance rejection control (ADRC) technique for load frequency control of a wind integrated power system when communication delays are considered. To improve the stability of frequency control, equivalent input disturbances (EID) compensation is used to eliminate the influence of the load variation. In wind integrated power systems, two area controllers are designed to guarantee the stability of the overall closed-loop system. First, a simplified frequency response model of the wind integrated time-delay power system was established. Then the state-space model of the closed-loop system was built by employing state observers. The system stability conditions and controller parameters can be solved by some linear matrix inequalities (LMIs) forms. Finally, the case studies were tested using MATLAB/SIMULINK software and the simulation results show its robustness and effectiveness to maintain power-system stability.

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Yoo, Sung Jin. "Adaptive State-Quantized Control of Uncertain Lower-Triangular Nonlinear Systems with Input Delay." Mathematics 9, no. 7 (April 1, 2021): 763. http://dx.doi.org/10.3390/math9070763.

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In this paper, we investigate the adaptive state-quantized control problem of uncertain lower-triangular systems with input delay. It is assumed that all state variables are quantized for the feedback control design. The error transformation method using an auxiliary time-varying signal is presented to deal with the compensation problem of input delay. Based on the error surfaces with the auxiliary variable, a neural-network-based adaptive state-quantized control scheme is constructed with the design of the input delay compensator. Different from existing results in the literature, the proposed method exhibits the following features: (i) compensating for the input delay effect by using quantized states; and (ii) establishing the stability of the adaptive quantized feedback control system in the presence of input delay. Furthermore, the boundedness of all the signals in the closed-loop and the convergence of the tracking error are analyzed. The effectiveness of the developed control strategy is demonstrated through the simulation on a hydraulic servo system.

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Song, Mingming, Hongmin Liu, Yanghuan Xu, Dongcheng Wang, and Yangyang Huang. "Decoupling Adaptive Smith Prediction Model of Flatness Closed-Loop Control and Its Application." Processes 8, no. 8 (July 26, 2020): 895. http://dx.doi.org/10.3390/pr8080895.

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Flatness control system is characterized by multi-parameters, strong coupling, pure time delay, which complicate the establishment of an accurate mathematical model. Therefore, a control scheme that combines dynamic decoupling, PI (Proportion and Integral) control and adaptive Smith predictive compensation is proposed. To this end, a dynamic matrix is used to decouple the control system. A multivariable coupled pure time-delay system is transformed into several independent generalized single-loop pure time-delay systems. Then, a PI-adaptive Smith predictive controller is constructed for the decoupled generalized single-loop pure time-delay system. Simulations show that the scheme has a simple and feasible structure, and good control performance. When the mathematical model of the control system is inaccurate, the control performance of adaptive Smith control method is evidently better than that of the ordinary Smith control method. The model is successfully applied to the cold rolling production site through LabVIEW, and the control accuracy is within 5I. This study reveals a new solution to the problem of coupled pure time-delay in flatness control system.

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Alnajdi, Aisha, Atharva Suryavanshi, Mohammed S. Alhajeri, Fahim Abdullah, and Panagiotis D. Christofides. "Machine learning-based predictive control of nonlinear time-delay systems: Closed-loop stability and input delay compensation." Digital Chemical Engineering 7 (June 2023): 100084. http://dx.doi.org/10.1016/j.dche.2023.100084.

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Sipahi, Rifat, and Silviu-Iulian Niculescu. "Stability of car following with human memory effects and automatic headway compensation." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 368, no. 1928 (October 13, 2010): 4563–83. http://dx.doi.org/10.1098/rsta.2010.0127.

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This paper addresses the study of some appropriate control strategies in order to guarantee the exponential stability of a class of deterministic microscopic car-following models including human drivers’ memory effects and automated headway controllers. More precisely, the delayed action/decision of human drivers is represented using distributed delays with a gap and the considered automated controller is of proportional derivative type. The analysis is performed in both delay parameter and controller gain parameter spaces, and appropriate algorithms are proposed. Surprisingly, large delays and/or gains improve stability for the corresponding closed-loop schemes. Finally, some illustrative examples as well as various interpretations of the results complete the presentation.

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Crevecoeur, F., and M. Gevers. "Filtering Compensation for Delays and Prediction Errors during Sensorimotor Control." Neural Computation 31, no. 4 (April 2019): 738–64. http://dx.doi.org/10.1162/neco_a_01170.

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Compensating for sensorimotor noise and for temporal delays has been identified as a major function of the nervous system. Although these aspects have often been described separately in the frameworks of optimal cue combination or motor prediction during movement planning, control-theoretic models suggest that these two operations are performed simultaneously, and mounting evidence supports that motor commands are based on sensory predictions rather than sensory states. In this letter, we study the benefit of state estimation for predictive sensorimotor control. More precisely, we combine explicit compensation for sensorimotor delays and optimal estimation derived in the context of Kalman filtering. We show, based on simulations of human-inspired eye and arm movements, that filtering sensory predictions improves the stability margin of the system against prediction errors due to low-dimensional predictions or to errors in the delay estimate. These simulations also highlight that prediction errors qualitatively account for a broad variety of movement disorders typically associated with cerebellar dysfunctions. We suggest that adaptive filtering in cerebellum, instead of often-assumed feedforward predictions, may achieve simple compensation for sensorimotor delays and support stable closed-loop control of movements.

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Chen, Wenying, and Jingyu Li. "Design of H∞ Predictive Controller for Networked Control System." Journal of Engineering Mechanics and Machinery 7, no. 1 (2022): 38–48. http://dx.doi.org/10.23977/jemm.2022.070106.

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For a class of network control systems with both data packet dropout and network communication delay problems, a new robust model predictive control method with compensation function is proposed. Considering that the system has interference problems, in the two cases of long-delay and short-delay, the packet loss problem is established as a Bernoulli sequence, and then a discrete NCS model based on the state observer is obtained. The state observer in the model can deal with the data packet dropout compensate and predict the state of the long-delay problem. Through linear matrix inequality and Lyapunov method, the controller is designed to obtain sufficient conditions for the closed-loop system to be exponentially stable and meet the specified performance indicators. Finally, compared with the method without any compensation measures, the method in this paper can get better control effect.

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Losert, Thomas, Martin Schlager, and Wilfried Elmenreich. "Fault-Tolerant Compensation of the Propagation Delay for Hard Real-Time Systems." Journal of Advanced Computational Intelligence and Intelligent Informatics 9, no. 4 (July 20, 2005): 346–52. http://dx.doi.org/10.20965/jaciii.2005.p0346.

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In control systems the jitter is a relevant problem since the majority of theoretical results for analysis and design of time-invariant systems do not apply for time-variant systems. Reducing the jitter increases the stability of the closed control-loop thus leading to enhanced reliability. This paper presents a general model that can be applied to bus topologies as well as to star topologies. Based on this model an algorithm is presented that allows to improve the precision of a set of distributed clocks by measuring the propagation delay of the communication lines in a fault-tolerant way and compensating the jitter introduced by the propagation delay. Some fault-tolerant architectures already provide means for coping with propagation delays but require manually entering the values in a configuration-tool. With this algorithm the system supports this error-prone task by providing validity checks for the entered values or measuring these values automatically thus rendering this maintenance step obsolete.

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Wang, Le, Haipeng Pan, Jinfeng Gao, and Dongdong Chen. "Predictive Compensation for Wireless Networked System with Time Delay and Packet Dropout Based on T-S Model." Abstract and Applied Analysis 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/953039.

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Based on the T-S model, a predictive compensation scheme including timer and counter for wireless networked system with long time delay and data packet dropout is proposed in this paper. By the separation principle, the state observation predictor and the state feedback controller are designed separately. For the case of fixed delay, the stability of the closed-loop networked control systems is discussed. Simulation by inverted pendulum system illustrates the effectiveness of the proposed method in wireless networked system based on T-S model.

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Shen, Shaobo, Aiguo Song, Tao Li, and Huijun Li. "Time delay compensation for nonlinear bilateral teleoperation: A motion prediction approach." Transactions of the Institute of Measurement and Control 41, no. 16 (July 10, 2019): 4488–98. http://dx.doi.org/10.1177/0142331219860928.

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This paper addresses the time delay compensation problem for nonlinear teleoperation system. A novel motion prediction approach is proposed based on a state observer with a cascade structure. The actual positions of master robot are estimated on the slave side by using delayed information of measurements. The prediction errors remain bounded under an appropriate set of assumptions for the system uncertainties. Moreover, an essential theorem for slave controller design is proposed to demonstrate performance recovery of the closed-loop system with cascade observer. By using the predictions, the forward time delay is effectively compensated when we design the controller of slave robot. Simulations are performed to verify the effectiveness of proposed method. The prediction results are highlighted through comparing with other two kinds of cascade predictors.

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Veremey, Evgeny I., Sergei V. Pogozhev, and Margarita V. Sotnikova. "Marine Autopilots’ Multipurpose Control Laws Synthesis for Actuators Time Delay." Journal of Marine Science and Engineering 8, no. 7 (June 28, 2020): 477. http://dx.doi.org/10.3390/jmse8070477.

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One analytical design problem involves constructing control laws for marine autopilot systems. Despite numerous known solutions, this problem can still be further developed by taking into account the actual conditions of the control system operation. An important issue for discussion is the feedback synthesis for marine ships with time delays in their rudders’ actuators. In this work, a new approach is proposed for providing all the desirable dynamic features of a closed-loop system with autopilot while taking into account the presence of a time delay. This approach is based on the predictive compensation of time delays via the specific transformation of an initially given reference controller with a special multipurpose structure. The applicability and effectiveness of the proposed method is further illustrated by a practical example of a controller design.

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Zahid, Ch Nauman, Mina Salim, Raja Ali Riaz, and Jamshed Iqbal. "A deterministic approach for design of supervisory control of LPV systems with delay." PLOS ONE 16, no. 8 (August 20, 2021): e0256408. http://dx.doi.org/10.1371/journal.pone.0256408.

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Linear Parameter Varying (LPV) systems and their control have gained attraction recently as they approximate nonlinear systems with higher order than ordinary linear systems. On the other hand, time delay is an inherent part of various real-life applications. A supervisory control structure is proposed in this paper for LPV systems subject to time delays. In the proposed control structure, a supervisor selects the most suitable controller from a bank of controllers; which desires to enhance the performance of closed-loop system in contrast with using a single robust controller. The analysis is based on the celebrated Smith predictor for time delay compensation and we provide a sufficient condition to assure the stability of the closed-loop switched system in terms of dwell time. Simulations on blood pressure control of hypertension patients in postoperative scenario are used to exemplify the effectiveness of the utilized technique. The operating region of the system is partitioned into five smaller operating regions to construct corresponding robust controllers and perform hysteresis switching amongst them. Simulation results witnessed that the proposed control scheme demonstrated a pressure undershoot less than the desired value of 10 mmHg while the Mean Arterial Pressure (MAP) remains within ±5 mmHg of the desired value.

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Litinskaia, E. L., K. V. Pozhar, and N. M. Zhilo. "Problems and methods of a closed-loop blood glucose control system construction." Journal of Physics: Conference Series 2091, no. 1 (November 1, 2021): 012020. http://dx.doi.org/10.1088/1742-6596/2091/1/012020.

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Abstract The automation of the insulin therapy in the closed-loop blood glucose control system is accompanied by such problems as delays of the feedback and the controlling action effect on blood glucose dynamics, difficulties in low and high glucose levels advance detection and timely compensation, a human factor, complexity of a mathematical model of control object building, evaluation of blood glucose control efficiency. In the paper, these automation problems and methods for their compensation are considered. The closed-loop system based on the model predictive control, adaptive adjustment of the controlling action and decision-making support was developed. Experimental testing with UVA/Padova Type 1 Diabetes Mellitus Simulator showed that the application of suggested methods in the closed-loop allows increasing the efficiency of the blood glucose maintaining in the target range.

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Chen, Xuemiao, Ziwen Wu, Jing Li, and Qianjin Zhao. "Adaptive Asymptotic Regulation for Uncertain Nonlinear Stochastic Systems with Time-Varying Delays." Symmetry 13, no. 12 (December 1, 2021): 2284. http://dx.doi.org/10.3390/sym13122284.

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In this paper, for a class of uncertain stochastic nonlinear systems with input time-varying delays, an adaptive neural dynamic surface control (DSC) method is proposed. To approximate the unknown continuous functions online, the neural network approximation technique was applied, and based on the DSC scheme, the desired controller was constructed. A compensation system is presented to compensate for the effect of the input delay. The Lyapunov–Krasovskii functionals (LKFs) were employed to compensate for the effect of the state delay. Compared with the existing works, based on using the DSC scheme with the nonlinear filter and stochastic Barbalat’s lemma, the asymptotic regulation performance of this closed-loop system can be guaranteed under the developed controller. To certify the availability for the designed control method, some simulation results are presented.

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Cui, Yang, Kaiqing Liu, Yang Zhao, and Xue Wang. "RobustH∞Control for a Class of Uncertain Switched Fuzzy Time-Delay Systems Based on T-S Models." Mathematical Problems in Engineering 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/234612.

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The problem of robustH∞control for a class of uncertain switched fuzzy time-delay systems is discussed for system described by T-S fuzzy model with Lyapunov stable theory and linear matrix inequality approach. A sufficient condition in terms of the LMI is derived such that the stability of the closed-loop systems is guaranteed. The continuous state feedback controller is built to ensure the asymptotically stable closed-loop system for all allowable uncertainties, with the switching law designed to implement the global asymptotic stability of uncertain switched fuzzy time-delay systems. In this model, each and every subsystem of the switched systems is an uncertain fuzzy one to which the parallel distributed compensation (PDC) controller of each sub fuzzy system system is proposed with its main condition given in a more solvable form of convex combinations. Such a switched control system is highly robust to varying parameters. A simulation shows the feasibility and effectiveness of the design method.

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Bas¸er, Ulviye. "Output Feedback H∞ Control Problem for Linear Neutral Systems: Delay Independent Case." Journal of Dynamic Systems, Measurement, and Control 125, no. 2 (June 1, 2003): 177–85. http://dx.doi.org/10.1115/1.1567316.

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This paper presents the solution of output feedback H∞ control problem for linear neutral systems with unknown constant multiple state delays in delay independent case, without any restrictions on plant matrices D12 and D21. First, some sufficient conditions for the solution of this problem are obtained in closed-loop system matrices in both linear matrix inequality (LMI) and algebraic Riccati inequality (ARI) forms, by standard Lyapunov-Krazovskii functional in delay independent multi-delay case. Because of the complexity of the solution of the compensator from these inequalities, equivalent sufficient conditions are derived for designing output feedback controller which stabilizes the closed-loop neutral system under consideration and guarantees an H∞-norm bound constraint on the disturbance attenuation. These conditions are of the form two ARIs and, for simplicity in computation equivalent LMIs are given. Finally, output feedback H∞ controller design is achieved and the results are illustrated in some numerical examples.

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Wang, Zhengqi, Liusen Sheng, Qunhai Huo, and Sipeng Hao. "An Improved Model Predictive Control Method for Three-Port Soft Open Point." Mathematical Problems in Engineering 2021 (June 29, 2021): 1–22. http://dx.doi.org/10.1155/2021/9910451.

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Soft open point (SOP) is a key power electronic device to improve the flexibility and stability of the distribution network and is becoming a research hotspot. The traditional double closed-loop control of SOP has a complex structure, difficult process of parameter design, and poor output power quality. To solve these problems, finite control set model predictive control (FCS-MPC) has been adopted. Since FCS-MPC involves a large amount of calculation and experiences delay in current tracking, an improved FCS-MPC with delay compensation is proposed for three-port SOP in this paper to replace the inner loop current control strategy. Improved model predictive control combines the two-step prediction method based on the voltage vector and vector angle compensation method. The vector method is used to construct a mathematical model and a prediction model of three-port SOP. Based on FCS-MPC, the two-step prediction method that takes voltage as the target is used to compensate for the current delay problem, and the amount of calculation is reduced by converting the control target. Meanwhile, the vector angle compensation method is used to compensate the future reference value. Finally, a simulation model is built in MATLAB/Simulink. The simulation results under steady state and dynamic conditions show that the proposed strategy can effectively improve the current delay and reduce the amount of calculation. Furthermore, it has better current tracking accuracy and faster dynamic response speed.

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Liu, Xuewen, Zhengcheng Qin, and Hongsheng Li. "Online Compensation of Phase Delay Error Based on P-F Characteristic for MEMS Vibratory Gyroscopes." Micromachines 13, no. 5 (April 19, 2022): 647. http://dx.doi.org/10.3390/mi13050647.

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In this paper, an online compensation method of phase delay error based on a Phase-Frequency (P-F) characteristic has been proposed for MEMS Coriolis Vibratory Gyroscopes (CVGs). At first, the influences of phase delay were investigated in the drive and sense mode. The frequency response was acquired in the digital control system by collecting the demodulation value of drive displacement, which verified the existence and influence of the phase delay. In addition, based on the P-F characteristic, that is, when the phase shift of the nonresonant drive force through the resonator is almost 0° or 180°, the phase delay of the gyroscope is measured online by injecting a nonresonant reference signal into the drive-mode dynamics. After that, the phase delay is self-corrected by adjusting the demodulation phase angle without affecting the normal operation of the gyroscopes. The approach was validated with an MEMS dual-mass vibratory gyroscope under double-loop force-to-rebalance (in-phase FTR and quadrature FTR) closed-loop detection mode and implemented with FPGA. The measurement results showed that this scheme can detect and compensate phase delay to effectively eliminate the effect of the quadrature error. This technique reduces the zero rate output (ZRO) from −0.71°/s to −0.21°/s and bias stability (BS) from 23.30°/h to 4.49°/h, respectively. The temperature sensitivity of bias output from −20 °C to 40 °C has reached 0.003 °/s/°C.

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KIM, TAEK RYONG, YOUNG HOON JOO, JIN BAE PARK, and GUANRONG CHEN. "ANTICONTROL OF CHAOS FOR A CONTINUOUS-TIME TAKAGI–SUGENO FUZZY SYSTEM VIA LOCAL TIME-DELAY FEEDBACK." International Journal of Bifurcation and Chaos 15, no. 12 (December 2005): 3883–94. http://dx.doi.org/10.1142/s0218127405014362.

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In this paper, a simple and systematic control design method is proposed for making a continuous-time Takagi–Sugeno (T–S) fuzzy system chaotic. The concept of parallel distributed compensation is employed to determine the structure of a fuzzy controller from a T–S fuzzy model. The fuzzy controller makes the T–S fuzzy model, which could be stable or unstable, bounded and chaotic. The verification of chaos in the closed-loop T–S fuzzy system is done by the following procedure. First, we establish an asymptotically approximate relationship between a continuous-time T–S fuzzy system with time-delay and a discrete-time T–S fuzzy system. Then, we verify the chaos in the closed-loop T–S fuzzy system by applying the Marotto theorem to its associated discrete-time T–S fuzzy system. The generated chaos is in the sense of Li and Yorke. Two examples are given to show that this methodology is simple and effective for anticontrol of chaos for a continuous-time T–S fuzzy system.

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Jiang, Wei, Hong-li Wang, Jing-hui Lu, Wei-wei Qin, and Guang-bin Cai. "Nonfragile Robust Model Predictive Control for Uncertain Constrained Systems with Time-Delay Compensation." Mathematical Problems in Engineering 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/1945964.

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This study investigates the problem of asymptotic stabilization for a class of discrete-time linear uncertain time-delayed systems with input constraints. Parametric uncertainty is assumed to be structured, and delay is assumed to be known. In Lyapunov stability theory framework, two synthesis schemes of designing nonfragile robust model predictive control (RMPC) with time-delay compensation are put forward, where the additive and the multiplicative gain perturbations are, respectively, considered. First, by designing appropriate Lyapunov-Krasovskii (L-K) functions, the robust performance index is defined as optimization problems that minimize upper bounds of infinite horizon cost function. Then, to guarantee closed-loop stability, the sufficient conditions for the existence of desired nonfragile RMPC are obtained in terms of linear matrix inequalities (LMIs). Finally, two numerical examples are provided to illustrate the effectiveness of the proposed approaches.

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Yan, T. H., B. He, X. D. Chen, and X. S. Xu. "The Discrete-Time Sliding Mode Control with Computation Time Delay for Repeatable Run-Out Compensation of Hard Disk Drives." Mathematical Problems in Engineering 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/505846.

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The presented is a study on the problem of disturbance rejection, specifically the periodic disturbance, by applying discrete-time sliding mode control method. For perturbations such as modeling errors and external disturbances, their compensation is formulated using the designed sliding mode control. To eliminate the effect of these perturbations, the convergence rate between the disturbance and their compensation has been shaped by an additional parameter. Decoupling of the resultant perturbation estimation dynamics from the closed loop dynamics is achieved. Computation time delay is also presented to address the perturbation effects. The approach developed ensures the robustness of the sliding mode dynamics to parameter uncertainties and exogenous disturbances, in addition to the complete rejection of the periodic disturbance component. Satisfactory simulation results as well as experimental ones have been achieved based on a fast servo system of a modern hard disk drive to illustrate the validity of the controller for repeatable run-out (RRO) compensation.

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Wang, Li, and Hongyinping Feng. "Performance output tracking for a one-dimensional unstable heat equation with input delay." IMA Journal of Mathematical Control and Information 39, no. 1 (January 18, 2022): 254–74. http://dx.doi.org/10.1093/imamci/dnab046.

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Abstract In this paper, we investigate the performance output tracking for a one-dimensional unstable heat equation with input delay and disturbance. Both the performance output and the disturbance are non-collocated to the controller. By writing the time delay as a transport equation, the control plant becomes a cascade system in which the transport equation can be regarded as the actuator dynamics of the unstable heat equation. As a result, the method of actuator dynamics compensation can be used. The difficulties caused by the non-collocated configuration are figured out in the method of trajectory planning. The full state feedback is presented to realize the output tracking, and an error based observer is constructed successfully. The exponential stability of the closed-loop system and the well-posedness of the observer are proved.

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Imangazieva, A. "Chain Network Control with Delay by an Auxiliary Loop Method." Mekhatronika, Avtomatizatsiya, Upravlenie 23, no. 11 (November 3, 2022): 570–76. http://dx.doi.org/10.17587/mau.23.570-576.

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The article is devoted to the development of control algorithms for a network of agents of a chain network, each agent of which is a linear plant with state delay, subject to the action of external disturbances under conditions of a priori uncertainty. In each agent of the network, the output of the previous agent is monitored, and the signal from the leading subsystem arrives only at the first agent of the network, the communication is one-way. Taking into account the time delay in the models of each agent of the network of such a structure makes them close to real ones. In agent control systems, disturbances are compensated by implementing the principle of invariance, namely, in each network agent, compensation for the action of external disturbances acting on the network agent from the outside, as well as internal disturbances caused by various modes of operation of the plant, is carried out by generating a special disturbance signal, and then it subsequent compensation with the help of an auxiliary loop and Khalil observers. A numerical example of a chain network consisting of four linear control plants is given under the conditions of interval uncertainty of the parameters of their mathematical models, state delay and the action of external uncontrolled disturbances. Numerical simulation was carried out in Matlab Simulink. Graphs of transient processes for tracking errors of agents of the chain network are presented, confirming the theoretical conclusions and illustrating the good performance of the control algorithms for the chain network.

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Dos Santos, Diego Pinto, Candice Müller, Fabio D'Agostini, Maria Cristina F. De Castro, and Fernando C. De Castro. "Symbol Synchronization for OFDM Receivers with FFT Transport Delay Compensation." Journal of Circuits, Systems and Computers 24, no. 05 (April 8, 2015): 1550076. http://dx.doi.org/10.1142/s0218126615500760.

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This paper proposes a new blind approach for time synchronization of orthogonal frequency division multiplexing (OFDM) receivers (RX). It is largely known that the OFDM technique has been successfully applied to a wide variety of digital communications systems over the past several years — IEEE 802.16 WiMax, 3GPP-LTE, IEEE 802.22, DVB T/H, ISDB-T, to name a few. We focus on the synchronization for the ISDB-T digital television system, currently adopted by several South American countries. The proposed approach uses the coarse synchronization to estimate the initial time reference and then, the fine synchronization keeps tracking the transmitter (TX) time reference. The innovation on the proposed approach regards to the closed loop control stabilization of the fine synchronization. It uses a smith predictor and a differential estimator, which estimates the difference between TX and RX clock frequencies. The proposed method allows the RX to track the TX time reference with high precision ([Formula: see text] sample fraction). Thus, the carriers phase rotation issue due to incorrect time reference is minimized, and it does not affect the proper RX IQ symbols demodulation process. The RX internal time reference is adjusted based on pilot symbols, called scattered pilots (SPs) in the context of the ISDB-T standard, which are inserted in the frequency domain at the inverse fast Fourier transform (IFFT) input in the TX. The averaged progressive phase rotation of the received SPs at the fast Fourier transform (FFT) output is used to compute the time misalignment. This misalignment is used to adjust the RX fine time synchronism. Furthermore, the proposed method has been implemented in an ISDB-T RX. The FPGA-based receiver has been evaluated over several multipath, Doppler and AWGN channel models.

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Xu, Li, and Fei Liu. "Fuzzy Based Model Predictive Control for Uncertain Nonlinear System." Advanced Materials Research 383-390 (November 2011): 2404–10. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.2404.

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In this paper, a model predictive control (MPC) scheme is investigated for uncertain nonlinear system with time delay and input constraint. First, the Takagi-Sugeno (T-S) fuzzy model is used to approximate the dynamics of nonlinear processes and the parallel distributed compensation (PDC) controllers which are parameter dependent and mirror the structure of the T-S plant model are proposed. Then a novel feedback PDC predictive controller obtained from the linear matrix inequality (LMI) solutions which can guarantee the stability of the closed-loop overall fuzzy system is put forward. Finally, a numerical example is provided to demonstrate the effectiveness and feasibility of the proposed method.

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Lin, Xiangze, Shuaiting Huang, Shihua Li, and Yun Zou. "Finite-time feedback control of an input-delay system with nonlinear saturating actuators." Transactions of the Institute of Measurement and Control 40, no. 10 (July 26, 2017): 3059–67. http://dx.doi.org/10.1177/0142331217713836.

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Finite-time feedback control of input-delay system with nonlinear saturating actuators is addressed in this paper. First, a state feedback controller is designed to make the closed-loop systems finite-time stable. Sufficient conditions which can guarantee finite-time stability of an input-delay system with saturating actuators are given in terms of the comparison function method. For the case where the states cannot be measured, an observer is presented to estimate the unavailable states and the observer-controller compensator strategy is proposed. Finally, an example is employed to illustrate the efficiency of the proposed method. It is not difficult to conclude from the analysis and the simulation results that by virtue of the proposed method the transient characteristics of the closed-loop system can be easily guaranteed to comply with the requirements of the practice.

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Zahradka, Nicole, Ahad Behboodi, Henry Wright, Barry Bodt, and Samuel Lee. "Evaluation of Gait Phase Detection Delay Compensation Strategies to Control a Gyroscope-Controlled Functional Electrical Stimulation System During Walking." Sensors 19, no. 11 (May 30, 2019): 2471. http://dx.doi.org/10.3390/s19112471.

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Functional electrical stimulation systems are used as neuroprosthetic devices in rehabilitative interventions such as gait training. Stimulator triggers, implemented to control stimulation delivery, range from open- to closed-loop controllers. Finite-state controllers trigger stimulators when specific conditions are met and utilize preset sequences of stimulation. Wearable sensors provide the necessary input to differentiate gait phases during walking and trigger stimulation. However, gait phase detection is associated with inherent system delays. In this study, five stimulator triggers designed to compensate for gait phase detection delays were tested to determine which trigger most accurately delivered stimulation at the desired times of the gait cycle. Motion capture data were collected on seven typically-developing children while walking on an instrumented treadmill. Participants wore one inertial measurement unit on each ankle and gyroscope data were streamed into the gait phase detection algorithm. Five triggers, based on gait phase detection, were used to simulate stimulation to five muscle groups, bilaterally. For each condition, stimulation signals were collected in the motion capture software via analog channels and compared to the desired timing determined by kinematic and kinetic data. Results illustrate that gait phase detection is a viable finite-state control, and appropriate system delay compensations, on average, reduce stimulation delivery delays by 6.7% of the gait cycle.

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Song, Xiaona, Mi Wang, Shuai Song, and Jingtao Man. "Dissipativity-Based Controller Design for Time-Delayed T-S Fuzzy Switched Distributed Parameter Systems." Complexity 2018 (October 17, 2018): 1–11. http://dx.doi.org/10.1155/2018/6215945.

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This paper studies fuzzy controller design problem for a class of nonlinear switched distributed parameter systems (DPSs) subject to time-varying delay. Initially, the original nonlinear DPSs are accurately described by Takagi-Sugeno fuzzy model in a local region. On the basis of parallel distributed compensation technique, mode-dependent fuzzy proportional and fuzzy proportional-spatial-derivative controllers are constructed, respectively. Subsequently, using single Lyapunov-Krasovskii functional and some matrix inequality methods, sufficient conditions that guarantee the stability and dissipativity of the closed-loop systems are presented in the form of linear matrix inequalities, which allow the control gain matrices to be easily obtained. Finally, numerical examples are provided to demonstrate the validity of the designed controllers.

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Zheng, Wei, Hong-bin Wang, and Zhi-ming Zhang. "Dynamic Output Feedback Compensation Control for Discrete Closed-Loop Nonlinear System with Multiple Time-Delays." Mathematical Problems in Engineering 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/6427807.

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This paper addresses the dynamic output feedback control problem for a class of discrete system with uncertainties and multiple time-delays. First, the system is decomposed into two subsystems based on the output matrix and input control matrix. Secondly, a dynamic compensator is employed for the first subsystem, and then, given the multiple uncertainties, the output feedback controller is designed based on the second subsystem and the dynamic compensator. Thirdly, by choosing the Lyapunov-Krasovskii function, it can be seen that the developed controller makes the closed-loop system convergent to an adjustable region, which can be rendered arbitrary small by adjusting design parameters. Compared with the previous researches, the proposed controller is not only smooth and memoryless, but also only dependent on the system output. Furthermore, with the given dynamic compensator, the controller design conditions are relaxed, while the approach is extended to the conventional nonlinear system. Finally, numerical example is given to illustrate the effectiveness of the theoretical results.

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Montgomery, J. C., and J. A. Macdonald. "Effects of temperature on nervous system: implications for behavioral performance." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 259, no. 2 (August 1, 1990): R191—R196. http://dx.doi.org/10.1152/ajpregu.1990.259.2.r191.

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Temperature change has a major impact on the function of the nervous system and its components, including altering synaptic gain and changing synaptic and conduction delays. Although many animals are subject to changes in body temperature, the degree of temperature change actually experienced by many poikilotherms is not well documented. The fact that many animals continue to exhibit coordinated sensorimotor function during changes in body temperature indicates that some form of temperature compensation has occurred within the nervous system. Compensations may occur automatically (opposing effects of temperature offsetting each other), they may be an inherent property of closed-loop systems, or they may be effected by more sophisticated control mechanisms such as those of the vertebrate cerebellum.

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Pal, Vipin Chandra, Richa Negi, and Ishaan Mudgal. "Design of nonlinear anti-windup compensator for time-delayed systems based on triple Lyapunov Functional." Transactions of the Institute of Measurement and Control 42, no. 5 (November 5, 2019): 997–1007. http://dx.doi.org/10.1177/0142331219880705.

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In this paper, an internal model control based anti-windup compensator (AWC) is designed for nonlinear systems subjected to time-varying delay and input saturation. By using Lyapunov Krasvoskii Functional, less conservative linear matrix inequality (LMI) based delay-dependent stability condition is derived by utilizing the information of delay. Triple integral Lyapunov Functional is used for finding the gains of AWC to guarantee the closed loop stability of the system and reduce the conservatism. The saturation nonlinearity is taken into account by using sector condition. Finally, the efficacy of proposed approach is shown by numerical examples.

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Jaafar, Anuar, Norhayati Soin, Sharifah F. Wan Muhamad Hatta, Sani Irwan Salim, and Zahriladha Zakaria. "Multipoint Detection Technique with the Best Clock Signal Closed-Loop Feedback to Prolong FPGA Performance." Applied Sciences 11, no. 14 (July 12, 2021): 6417. http://dx.doi.org/10.3390/app11146417.

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The degradation effect of a field-programmable gate array becomes a significant issue due to the high density of logic circuits inside the field-programmable gate array. The degradation effect occurs because of the rapid technology scaling process of the field-programmable gate array while sustaining its performance. One parameter that causes the degradation effect is the delay occurrence caused by the hot carrier injection and negative bias temperature instability. As such, this research proposed a multipoint detection technique that detects the delay occurrence caused by the hot carrier injection and negative bias temperature instability degradation effects. The multipoint detection technique also assisted in signaling the aging effect on the field-programmable gate array caused by the delay occurrence. The multipoint detection technique was also integrated with a method to optimize the performance of the field-programmable gate array via an automatic clock correction scheme, which could provide the best clock signal for prolonging the field-programmable gate array performance that degraded due to the degradation effect. The delay degradation effect ranged from 0° to 360° phase shifts that happened in the field-programmable gate array as an input feeder into the multipoint detection technique. With the ability to provide closed-loop feedback, the proposed multipoint detection technique offered the best clock signal to prolong the field-programmable gate array performance. The results obtained using the multipoint detection technique could detect the remaining lifetime of the field-programmable gate array and propose the best possible signal to prolong the field-programmable gate array’s performance. The validation showed that the multipoint detection technique could prolong the performance of the degraded field-programmable gate array by 13.89%. With the improvement shown using the multipoint detection technique, it was shown that compensating for the degradation effect of the field-programmable gate array with the best clock signal prolonged the performances.

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Chen, Jing Wen, and Xiao Ping Sun. "The Research of Re-Winder Bottom Roller Feed-Forward Control Tactic." Advanced Materials Research 225-226 (April 2011): 146–49. http://dx.doi.org/10.4028/www.scientific.net/amr.225-226.146.

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As the last working procedure in the paper production process, re-winder control technology is crucial to the quality of finished paper scroll. To obtain the paper scroll with inner tight and outer loose, the control of bottom rollers must satisfy the double closed-loop feedback control with torque difference. While the feedback control exists time-delay and may cause the slowness of system response. Here on the basis of re-winder production process and control requirements, a novel feed-forward control tactics is proposed to combine with feedback control. According to the compensation of feed-forward control, rapid system response is obtained and system performance is improved. And corresponding simulation shows the validity and feasibility of the feed-forward control tactics.

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Xing, Jinsheng, and Naizheng Shi. "Adaptive Stabilization Control for a Class of Complex Nonlinear Systems Based on T-S Fuzzy Bilinear Model." Mathematical Problems in Engineering 2015 (2015): 1–11. http://dx.doi.org/10.1155/2015/659521.

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This paper proposes a stable adaptive fuzzy control scheme for a class of nonlinear systems with multiple inputs. The multiple inputs T-S fuzzy bilinear model is established to represent the unknown complex systems. A parallel distributed compensation (PDC) method is utilized to design the fuzzy controller without considering the error due to fuzzy modelling and the sufficient conditions of the closed-loop system stability with respect to decay rateαare derived by linear matrix inequalities (LMIs). Then the errors caused by fuzzy modelling are considered and the method of adaptive control is used to reduce the effect of the modelling errors, and dynamic performance of the closed-loop system is improved. By Lyapunov stability criterion, the resulting closed-loop system is proved to be asymptotically stable. The main contribution is to deal with the differences between the T-S fuzzy bilinear model and the real system; a global asymptotically stable adaptive control scheme is presented for real complex systems. Finally, illustrative examples are provided to demonstrate the effectiveness of the results proposed in this paper.

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Shen, Gang, Zhen-Cai Zhu, Xiang Li, Qiang Meng, Yu Tang, Wei Li, and Shan-Zeng Liu. "Robust fault-tolerant tracking control for a class of nonlinear systems based on position measurements only." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 230, no. 6 (August 3, 2016): 486–97. http://dx.doi.org/10.1177/0954408915576290.

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The problem of trajectory tracking for a class of nonlinear systems in the presence of un-modeled dynamics, parameter variations and even the actuator faults is investigated in this paper. A novel fault-tolerant control scheme is proposed by combining the nominal model-based controller and time-delay controller, which are adopted to achieve the real-time dynamic compensation and guarantee the robust stability of the controlled systems, respectively. Moreover, high-quality differential signals are unavailable in the presence of disturbances and measurement noise, which limit the performance of closed-loop systems in practice. Therefore, an extended state observer (ESO) is introduced to obtain high-quality differential signal estimations based on position measurements only. Furthermore, the effectiveness of the proposed novel control scheme is verified by testing in the spacecraft attitude tracking system.

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Hu, Songlin, Dong Yue, Min Shi, and Xiangpeng Xie. "Discrete-Time Event-Triggered Control of Nonlinear Wireless Networked Control Systems." Abstract and Applied Analysis 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/860438.

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This paper investigates the problem of stabilization of nonlinear discrete-time networked control systems (NCSs) with event-triggering communication scheme in the presence of signal transmission delay. A Takagi-Sugeno (T-S) fuzzy model and parallel-distributed compensation (PDC) scheme are first employed to design a nonlinear fuzzy event-triggered controller for the stabilization of nonlinear discrete-time NCSs. The idea of the event-triggering communication scheme (i.e., a soft computation algorithm) under consideration is that the current sensor data is transmitted only when the current sensor data and the previously transmitted one satisfy a certain state-dependent trigger condition. By taking the signal transmission delay into consideration and using delay system approach, a T-S fuzzy delay system model is established to describe the nonlinear discrete-time NCSs with event-triggering communication scheme. Attention is focused on the design of fuzzy event-triggered controller which ensures asymptotic stability of the closed-loop fuzzy systems. Linear matrix inequality- (LMI-) based conditions are formulated for the existence of admissible fuzzy event-triggered controller. If these conditions are feasible, a desired fuzzy event-triggered controller can be readily constructed. A nonlinear mass-spring-damper mechanical system is presented to demonstrate the effectiveness of the proposed method.

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Kos, Tomaž, Mikuláš Huba, and Damir Vrančić. "Parametric and Nonparametric PID Controller Tuning Method for Integrating Processes Based on Magnitude Optimum." Applied Sciences 10, no. 17 (August 30, 2020): 6012. http://dx.doi.org/10.3390/app10176012.

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Integrating systems are frequently encountered in power plants, paper-production plants, storage tanks, distillation columns, chemical reactors, and the oil industry. Due to the open-loop instability that leads to an unbounded output from a bounded input, the efficient control of integrating systems remains a challenging task. Many researchers have addressed the control of integrating processes: Some solutions are based on a single closed-loop controller, while others employ more complex control structures. However, it is difficult to find one solution requiring only a simple tuning procedure for the process. This is the advantage of the magnitude optimum multiple integration (MOMI) tuning method. In this paper, we propose an extension of the MOMI tuning method for integrating processes, controlled with a two-degrees-of-freedom (2-DOF) proportional–integral–derivative (PID) controller. This extension allows for calculations of the controller parameters from either time domain measurements or from a process transfer function of an arbitrary order with a time-delay, when both approaches are exactly equivalent. The user has the option to emphasise disturbance-rejection or tracking with the reference weighting factor b or apply two different reference filters for the best overall response. The proposed extension was also compared to other tuning methods for the control of integrating processes and tested on a charge-amplifier drift-compensation system. All closed-loop responses were relatively fast and stable, all in accordance with the magnitude optimum criteria.

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Chen, Wen Ying. "Robust Η_∞ Controller Design for Networked Control Systems with Exponential Convergence." Applied Mechanics and Materials 475-476 (December 2013): 621–27. http://dx.doi.org/10.4028/www.scientific.net/amm.475-476.621.

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The output feedback exponential robust control for networked control systems with stochastic network-induced delay and packet dropout is studied. Firstly, a state observer is designed for estimating the state values and compensating data dropouts. Then the closed system is modeled as asynchronous dynamical system constrained by configuration event rate. By using Lyapunov principle, sufficient and necessary conditions for robust stability and exponential stability of the closed loop system is obtained and the output feedback controller design method is presented. Simulation example for the design is done, comparing with the other relative methods, the results shows the validity of the method.

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Zhang, Lingtan, Yue Shen, Long Wang, Jia Jia, and Lingzhi Wei. "Rotation Speed Control of the Rotary Valve in MWD Tools Based on Speed Feedforward Compensation." Mathematical Problems in Engineering 2021 (April 5, 2021): 1–8. http://dx.doi.org/10.1155/2021/5565672.

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The rotary valve speed control, seriously affected by the nonlinear characteristic of rotary valve load torque, affects the generation of drilling fluid pressure phase shift keying (PSK) signal and its quality. The calculation model feedforward of the load torque acts on the speed control system and enables the motor voltage to change according to the law of calculation model, and the linearization correction of the speed system is performed. Additionally, the flow measurement is introduced into the calculation model of the load torque to track the load torque change with the flow, suppressing the influence of large changes in flow rate on open-loop control of rotary valve speed. The closed-loop proportional-integral-derivative (PID) control is formed by negative feedback of speed, and the PID parameter value rule is established based on the rapid decay control of transient component in the rotary valve speed step response, which speeds up the tracking of the rotary valve speed following the control voltage pulse and reduces the distortion of the drilling fluid pressure PSK signal, increasing the frequency of the drilling fluid pressure carrier and improving the transmission rate of downhole information. Simulink simulation indicates that the closed-loop PID control of rotary valve speed can track the change of control voltage pulse quickly and strongly suppress the interference influences from flow measurement error and load torque calculation model deviation.

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Rodríguez-Seda, Erick J. "Passive Transparency Compensation for Bilateral Teleoperators with Communication Delays." Journal of Robotics 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/861425.

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One of the main challenges in the realization of time-delayed bilateral teleoperators is the stable adaptation of transparency when the remote environmental dynamics are time-varying. In this paper, we propose a bilateral control strategy that passively adjusts the transparency of the system when the slave robot transitions between two different environments. The proposed controller exploits the effect that the wave impedance (a design parameter of the passivity-based scattering transformation) has on transparency without comprising closed-loop stability, regardless of time-varying communication delays. To properly adjust transparency, the control scheme smoothly switches the wave impedance parameter between a low value, ideal for free motion, and a sufficiently large value, suited for hard-contact tasks. We show that, by adopting this strategy, the transmitted impedance to the operator approximates more closely the environmental impedance value. Furthermore, we theoretically prove master-slave position coordination and force tracking under different scenarios. Simulation results illustrate the effectiveness of the proposed control strategy.

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Bu, Feng, Shuwen Guo, Bo Fan, and Yiwang Wang. "Effect of Quadrature Control Mode on ZRO Drift of MEMS Gyroscope and Online Compensation Method." Micromachines 13, no. 3 (March 8, 2022): 419. http://dx.doi.org/10.3390/mi13030419.

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The quadrature coupling error is an important factor that affects the detection output of microelectromechanical system (MEMS) gyroscopes. In this study, two quadrature error control methods, quadrature force-to-rebalance control (Mode I) and quadrature stiffness control (Mode II) were analyzed. We obtained the main factors affecting the zero-rate output (ZRO) under force-to-rebalance (FTR) closed-loop detection. The analysis results showed that the circuit phase delay in Mode I caused the quadrature channel to leak into the in-phase channel. However, in Mode II, the quadrature coupling stiffness was corrected in real time, which effectively improved the stability of the ZRO. The changes in the vibration displacement and Q-factor were the main factors for the ZRO drift in Mode II. Therefore, we propose an online compensation method for ZRO drift based on multiparameter fusion. The experimental results on a cobweb-like disk resonator gyroscope (CDRG) with a 340 k Q-factor showed that the bias instability (BI) of Mode II was significantly better than that of Mode I. After online compensation, the BI reached 0.23°/h, and the bias repeatability reached 3.15°/h at room temperature.

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Yang, Hong, Huan Huan Lü, and Le Zhang. "Output Switching Control of a Class of Time-Delay Fuzzy Systems." Applied Mechanics and Materials 670-671 (October 2014): 1358–61. http://dx.doi.org/10.4028/www.scientific.net/amm.670-671.1358.

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For a class of T-S fuzzy time-delay systems, the problem of designing a static output feedback controller is considered via the parallel distributed compensation (PDC) approach. Namely, when one controller can not assure the stability of system, a controller switching strategy in certain set of controllers may stabilize the system. Moreover the adoption of this strategy often improves the performance of system even in the case that a single controller can stabilize the system. By defining multiple Lyapunov functions, the sufficient condition for the existence of the static out put feedback controller is presented in terms of linear matrix inequality (LMI), which guarantees the stability of the close-loop system for the switching cases. The simulation results demonstrate the effectiveness of the proposed method.

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Xue, Hua, and Yue Fan. "Study on Fuzzy PI Control Strategies of Networked Control System." Advanced Materials Research 860-863 (December 2013): 2337–41. http://dx.doi.org/10.4028/www.scientific.net/amr.860-863.2337.

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When using a remote networked control system, a network-induced time-delay is generated, which causes advert effects on the closed-loop networked control system such as performance degradation and system destabilization. For solving the time-delay in remote control system, intelligent fuzzy logic compensator is introduced in this paper to improve the traditional networked PI control system. In the full adaptive fuzzy parameter adjustment, off-line optimization and on-line adaptation are applied to the design of the controller, So that the consequent parameters can be tuned adaptively, As well as the membership functions in the antecedent part Simulation results of a networked controlled Brushless DC motor is used to illustrate the effectiveness and feasibility of the proposed fuzzy PI control scheme.

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Strauss, R., S. Schuster, and K. G. Götz. "Processing of artificial visual feedback in the walking fruit fly Drosophila melanogaster." Journal of Experimental Biology 200, no. 9 (May 1, 1997): 1281–96. http://dx.doi.org/10.1242/jeb.200.9.1281.

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A computerized 360 degrees panorama allowed us to suppress most of the locomotion-induced visual feedback of a freely walking fly without neutralizing its mechanosensory system ('virtual open-loop' conditions). This novel paradigm achieves control over the fly's visual input by continuously evaluating its actual position and orientation. In experiments with natural visual feedback (closed-loop conditions), the optomotor turning induced by horizontal pattern motion in freely walking Drosophila melanogaster increased with the contrast and brightness of the stimulus. Conspicuously striped patterns were followed with variable speed but often without significant overall slippage. Using standard open-loop conditions in stationary walking flies and virtual open-loop or closed-loop conditions in freely walking flies, we compared horizontal turning induced by either horizontal or vertical motion of appropriately oriented rhombic figures. We found (i) that horizontal displacements and the horizontal-motion illusion induced by vertical displacements of the oblique edges of the rhombic figures elicited equivalent open-loop turning responses; (ii) that locomotion-induced visual feedback from the vertical edges of the rhombic figures in a stationary horizontal position diminished the closed-loop turning elicited by vertical displacements to only one-fifth of the response to horizontal displacements; and (iii) that virtual open-loop responses of mobile flies and open-loop responses of immobilized flies were equivalent in spite of delays of up to 0.1 s in the generation of the virtual stimulus. Horizontal compensatory turning upon vertical displacements of oblique edges is quantitatively consistent with the direction-selective summation of signals from an array of elementary motion detectors for the horizontal stimulus components within their narrow receptive fields. A compensation of the aperture-induced ambiguity can be excluded under these conditions. However, locomotion-induced visual feedback greatly diminished the horizontal-motion illusion in a freely walking fly. The illusion was used to assay the quality of open-loop simulation in the new paradigm.

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Journal articles on the topic 'Closed loop delay compensation'

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