Integral Variable Structure Control Research Articles

Proportional and Integral Variable Structure Controller (PI –VSC) for Grid Connected PWM Voltage Source Converter

Proportional and Integral Variable Structure Controller (PI –VSC) for Grid Connected PWM Voltage Source Converter

Variable Structure Controller for a Rotary Dryer (Dept.E)

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On the performance of a fuzzy variable structure satellite attitude controller under sensor and actuator uncertainties

Controlling the attitude of a satellite with high accuracy and stability under both sensor and actuator delay is a great problem. It is possible to correct for errors, but a robust controller is more preferable. In this study, the attitude of a 3-DoF satellite model incorporating uncertainties (delays in handling both sensors and actuators) is controlled using a suitably designed integral fuzzy variable structure (IFVSC) controller. The attitude control accuracy of the IFVSC is evaluated and compared to other reference controllers (one is a PID controller and the other is a loop shaping controller). IFVSC is found to perform well with Td = 0.2 s sensor and actuator data delay.

Design of Integral Variable Structure Controller in Speed Tracking of Wind Driven Generator

In order to obtain the optimum power factor through maintaining the ratio of blade tip speed to wind speed, a new method for controller design of wind driven generator speed tracking is proposed basing on variable structure control theory. Integral variable of generator speed is introduced into the system equation. Switching surface of variable structure controller is founded with the error of generator speed. Adaptive estimation for wind disturbance and uncertain parameters of system dynamics model is adopted to derive control algorithm for rotation torque in the process of generator speed tracking. Simulation results show that speed tracking precision of wind driven generator is improved by integral variable structure controller. The method proposed in this article is effective and feasible.

An integral variable structure control scheme for non-overshooting responses

This article presents an improved integral variable structure control scheme to avoid overshooting responses for a class of second-order plants. The proposed sliding dynamics have two integral state variables. One integral state variable is initially specified to enable existence of a sliding mode throughout an entire response. The other’s initial value is assigned to avoid overshooting output responses. It is shown that the integral state is initially chosen to be a nonlinear function of the plant’s initial state to avoid an overshooting response. This article also reports the experimental results for controlling the position of a screw-driven actuator with various payloads and initial velocities, in order to show the effectiveness of the proposed scheme.

Dynamical adaptive integral backstepping variable structure controller design for uncertain systems and experimental application

SummaryIn this study, a dynamical adaptive integral backstepping variable structure control (DAIBVSC) system based on the Lyapunov stability theorem is proposed for the trajectory tracking control of a nonlinear uncertain mechatronic system with disturbances. In this control scheme, no prior knowledge is required on the uncertain parameters and disturbances because it is estimated by two types of dynamical adaptive laws. These adaptive laws are integrated into the dynamical adaptive integral backstepping control and variable structure control (VSC) parts of the DAIBVSC. The dynamical adaptive law in the dynamical adaptive integral backstepping control part updates parametric uncertainties, while the other in the VSC part adapts upper bounds of non‐parametric uncertainties and disturbances. In order to achieve a more robust output tracking and better parameter adaptation, the control system is extended by one integrator and sliding surface is augmented by an integral action. Experimental evaluation of the DAIBVSC is conducted with respect to performance and robustness to parametric uncertainties. Experimental results of the DAIBVSC are compared with those of a traditional VSC. The proposed DAIBVSC exhibits satisfactory output tracking performance, good estimation of the uncertain parameters and can reject disturbances with a chattering free control law. Copyright © 2017 John Wiley & Sons, Ltd.

Apply Novel Grey Model Integral Variable Structure Control to Air‐Ball‐Suspension System

AbstractThe magnetic suspension ball system has been researched for many years. A new air‐ball‐suspension system different from the magnetic force is developed in this manuscript. The non‐symmetric and time delay phenomena will be shown in this system. For the modeling, the piece‐wised approximated grey model is used to establish the pseudo model. Based on the pseudo model, the integral variable structure control is used to guide the sliding motion. Finally, the experimental results show the proposed control scheme's practical performance.

A Local Controller for Discrete-Time Large-Scale System by Using Integral Variable Structure Control

A new local controller for discrete-time integral variable structure control of a large-scale system with matched and unmatched uncertainty is presented. The local controller is able to bring the large-scale system into stability by using only the states feedback from individual subsystem itself. A new theorem is established and proved that the controller is able to handle the effect of interconnection for the large-scale system with matched and unmatched uncertainty, and the system stability is ensured. The controller is able to control the system to achieve the quasi-sliding surface and remains on it. The results showed a fast convergence to the desired value and the attenuation of disturbance is achieved.

Torque Ripple Reduction in Brushless DC Drives Based on Reference Current Optimization Using Integral Variable Structure Control

In this paper, a current optimization control method for reducing torque ripple in brushless dc drives using integral variable structure control (IVSC) is proposed. The conventional current control method will result in torque ripple if the back electromotive force (EMF) is a nonideal trapezoidal waveform. Based on back-EMF waveforms, the proposed method can optimize the reference currents in both two-phase conduction mode and commutation mode. A Luenberger full-order estimator is designed in order to estimate back-EMF waveforms. During commutation, commutation control with two-phase or three-phase switching mode is employed to reduce torque ripple by controlling the currents of noncommutated windings to trace the optimized reference current, and a three-phase inverter is switched between the two switching modes according to the current rate of change and the difference between the reference current and the actual current. Current controllers using IVSC, which exhibits broadband noise-suppressing capacity and strong robustness against external disturbances, are designed to obtain optimal phase currents, and the experimental results validate the effectiveness of the proposed method.

Control of Trajectory Kinematics for Flexible Manipulators Applying Integral Variable Structure Strategy

Tracking control of manipulators with joint flexibility is considered to achieve a higher control technique performance. An integral variable structure control (IVSC) approach for robot manipulators is presented for accurate servo-tracking in the presence of load variation, parameter uncertainty and nonlinear dynamic interactions. A procedure is proposed for choosing the control function so that it guarantees the existence of the sliding mode and for determining the coefficients of the switching plane and integral control gain. Furthermore, a modified proper continuous function is introduced to overcome the chattering problem. The proposed (IVSC) approach has been simulated for a two-degree of freedom flexible joint robot, each joint modeled by two-equations of second order. Stability is insured by the use of Liapunov's direct method. The simulation results demonstrate the potential of the proposed scheme. Keywords: Flexible joint robot, Integral variable structure system, Sliding mode, Switching plane, Servo- tracking, Stability criterion, Dynamic uncertainty, Chatter.

자동피킹 시스템 구동용 선형 유도 모터 드라이브 설계 및 적분형 가변구조 제어 기반의 강인 위치 제어기 설계

고 정밀도와 고 속응성의 물류 이송을 위한 자동피킹 시스템 (Automatic Picking System; APS) 구동용 선형 유도 모터 드라이브의 설계 및 강인한 위치 제어 기법이 제안된다. 모델 불확실성에 대한 강인한 위치 제어기 설계를 위해서 적분형 가변구조 제어 기법이 고려된다. APS의 외란추력, 질량 및 마찰계수 등의 기계적 파라미터 변화는 위치 제어 성능에 직접적 영향을 주며 이러한 불확실성 하에서도 강인한 위치 응답 성능을 보유하는 위치 제어기가 설계된다. 선형 유도 모터의 모델을 위한 Simulink 라이브러리가 상태방정식으로부터 개발되며 이를 활용한 Matlab - Simulink 기반의 비교 시뮬레이션을 통해 제안된 방식이 강인한 위치 응답 성능을 가지며 고 정밀도와 고 속응성을 요구하는 APS에 적합함이 입증된다. To implement an automatic picking system (APS) in distribution center with high precision and high dynamics, this paper presents a design of a linear induction motor (LIM) drive and robust position controller based on integral variable structure control (IVSC) scheme. The force disturbance as well as the mechanical parameter variation such as the mass and friction coefficient gives a direct influence on the position control performance of APS. To guarantee a robust control performance in the presence of such uncertainty, a robust position controller is designed. A Simulink library is developed for the LIM model from the state equation. Through this model and comparative simulation based on Matlab - Simulink, it is proved that the proposed scheme has a robust control nature and is most suitable for APS.

Three effective vectors‐based current control scheme for four‐switch three‐phase trapezoidal brushless DC motor

This study presents a novel three effective vectors (TEV) current control scheme for four-switch three-phase inverter in cost-effective brushless DC motor drive with improved performance. This scheme overcomes the possible distortion of three-phase currents caused by phase C back-EMF, and quasi-square current waveforms are attained by inserting two adjusting vectors in each control period based on the conventional switching modulation scheme. The duty cycles of the two adjusting vectors are further calculated using a simple P controller. Integral variable structure control principle with advantages of high bandwidth and strong robustness against external disturbance is used to control the tracing of reference current by actual currents. The stability of the proposed TEV current control scheme is demonstrated by selecting a candidate Lyapunov function, based on which the range of duty cycles of adjusting vectors are also determined. Experimental results verify that the proposed scheme is simple and can provide small current ripple, with good performance in speed.

Adaptive Switching Plane of Integral Variable Structure Control for Speed Control of Permanent Magnet Synchronous Motor Drives

This article presents a robust speed controller for field-oriented controlled permanent magnet synchronous motor drives. The proposed controller is designed using integral variable structure control combined with a linear quadratic regulator. The linear quadratic regulator scheme is used to decide the optimal feedback gain to shape the system dynamics by tuning the integral variable structure control switching plane to guarantee the robustness of the control algorithm in both reaching and sliding phases. The complete drive is implemented in real time using a digital signal processor control board (DS1102, Texas Instruments, dSPACE GmbH, Germany). The tracking properties and robustness of the proposed scheme are examined through both simulations and experimental work. It guarantees accurate control performance in the presence of parameter variation, step speed change, and load disturbances. The performance of the permanent magnet synchronous motor drive system with a conventional proportional-integral controller is presented in comparison with the proposed controller. The results show a significant improvement in both the transient and steady-state responses over the conventional proportional-integral controller.

Adaptive and robust speed control of interior permanent magnet synchronous motor drives

This paper presents a robust speed controller for field oriented controlled interior permanent magnet synchronous motor (IPMSM) drives. The proposed controller is designed using integral variable structure control (IVSC) combined with linear quadratic regulator (LQR). The LQR scheme is used to decide the optimal feedback gain to shape the system dynamics by tuning the IVSC switching plane to guarantee the robustness of the control algorithm. The complete drive is implemented in real-time using digital signal processor (DSP) control board DS1102. The tracking properties and robustness of the proposed scheme are examined through both simulations and experimental work. It guarantees accurate control performance in the presence of parameter variations, step speed change and load disturbances. The performance of IPMSM drive system with a conventional proportional-integral (PI) controller is presented in comparison with the proposed controller. The results show a significant improvement in both the transient and steady state responses over the conventional PI controller.

Grid Synchronization of Doubly-fed Induction Generator Using Integral Variable Structure Control

This paper proposes a novel direct voltage control scheme, using integral variable structure control to synchronize a doubly fed induction generator (DFIG)-based wind energy conversion system (WECS) to the grid. The proposed scheme directly controls the stator terminal voltage of the DFIG to track the grid voltage without current control loop; hence, the structure of controller is simplified. The control scheme includes parametric uncertainty and external disturbances into the formed design procedure; hence, the proposed scheme has better robustness than existing synchronization methods. Both computer simulation and hardware implementation results are presented to demonstrate the advantages of the proposed scheme.

Applying Modified MIMO DIVSC to Synchronism and Tension Control of Dual Motor Systems

In industrial manufacturing systems, one or more client motors are often arranged to follow the velocity of the master motor. The speed difference between these motors will affect the tension of the product. Hence, the synchronized control and the tension control are the important research topics in the manufacturing process. This paper proposes a novel modified multi-input-multi-output (MIMO) discrete integral variable structure control (DIVSC) for the synchronism and tension control of dual motor systems. By the Grey model theory, the unknown model of tension control can be established on-line to be a pseudo-Grey model. Based on these pseudo-Grey models, the model-based MIMO DIVSC can proceed with the design procedures. Finally, a prototype of the dual motor system is developed for testing the performance of the proposed control scheme. Experimental results will show the robust potential and the practicability of the proposed controller.

Integral variable structure current control of DFIG-based wind turbines near cut-in speed

Based on the grid voltage orientated vector control technique, a novel integral variable structure controller for current control of variable speed doubly fed induction generator (DFIG) wind turbines near cut-in wind speed is proposed. The proposed current controller can not only ensure generators' safe cut-in switches to the grid, but also maximum energy capture after switch motion without any regulations. By these, simulations of a 1.5 MW DFIG-based wind turbine near cut-in wind speed are separately conducted under integral variable structure control (IVSC) and PI control. The results show that IVSC strategy, which gives better dynamic response, less static error, smaller controller output dithering, stronger global robustness against generator parameters uncertainty and the grid voltage fluctuation, as well as needless controller regulation after cutting-in the grid, obviously preponderates over traditional PI control for DFIG-based wind turbines near cut-in speed.

Synchronization and tension control of dual motor systems via MIMO discrete pseudo model following integral variable structure control

In industrial manufacturing systems , the one or the more client motors are often arranged to follow the velocity of the master motor. The speed difference between these motors will effect the tension of the product. Hence, the synchronized control and the tension control are the important research topics in the manufacturing process. This paper proposes a novel modified multi-input–multi-output discrete pseudo model following integral variable structure control (MIMO DPMFIVSC) for the synchronism and tension control of dual motor system. By Grey model theory, the unknown model of tension control can be on-line established to be a pseudo grey model. A real time reference model is also transferred by the grey theory to accumulated model. The discrete integral variable structure control rule is used to eliminate the error between the pseudo and accumulated models. This object will achieve the model following work. Finally, a prototype of the dual motor system is developed for testing the performance of the proposed control scheme. Experimental results will show the robust potential and the practicability of the proposed controller.

Integral variable-structure control with variable-structure sliding dynamics for antireset windup

This paper proposes a scheme of integral variable-structure control with variable-structure sliding dynamics, referred to as VSSD-IVSC, based on the framework of the so-called global sliding-mode control (GSMC) technique. Previous GSMC schemes encompass the robust eigenvalue-assignment GSMC (REA-GSMC) and the integral variable-structure control (IVSC). All GSMC schemes feature the insurance of existence of a sliding mode throughout an entire response for performance robustness. It is shown in this paper that both REA-GSMC and IVSC lead to the same robust tracking performance in theory. In practical implementations the IVSC has better steady-state error characteristics than the REA-GSMC. However, due to control saturation, the IVSC may suffer from the integrator windup problem common to control methods with integral compensation. The VSSD-IVSC scheme is proposed to combine the REA-GSMC and the IVSC using the GSMC framework, and it has variable-structure sliding dynamics for antireset windup. Experiments were conducted on a two-link direct-drive manipulator to demonstrate the effectiveness of the proposed scheme.

A novel pseudo—model following integral variable structure control for vision feedback autonomous mobile robots

The control of autonomous mobile robots is an important topic in the literature of intelligent robotics. With great progress in intelligent systems, mobile robots are often autonomously driven. The computer vision replaces the human eye to be the feedback component and, through image processing, the necessary information can be deciphered. However, owing to the complexity of the whole system, a mathematical model is usually not available. Hence, many model—based robust control rules cannot be applied to vision—guided autonomous mobile robots. At the same time, the calculation of image processing takes up a long time, from fetching the image to creating the image information. In order to solve these problems, this paper proposes a novel pseudo—model following integral variable structure control (PMF—IVSC). By the grey model (GM(1, 2)) method, i.e. the grey model with one output and two inputs, the plant and the reference model are converted into an accumulated model and a pseudo—reference model respectively. Applying the IVSC, the accumulated model is governed to follow the pseudo—reference model. The PMF—IVSC will successfully solve the unknown system's model following control. Finally, an experimental mobile robot is developed to examine the potential of the proposed control scheme. This paper carries out the vision—based experiment of automatically driving while lane following. The experimental results show that the proposed controller will eliminate the swinging phenomenon and increase the accuracy while tracking. The results also show the practical capability of the proposed rule in intelligent robotic systems.