• Title, Summary, Keyword: variable structure system

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Design of Improved Discrete Variable Controller for Induction motor Position control

  • Jeon, Hee-Jong;Jeong, Eull-Gi;Kim, Beung-Jin;Kim, Sang-Woo;Lim, Byung-Kuk
    • Proceedings of the KIPE Conference
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    • pp.404-409
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    • 1998
  • In this paper, the discrete variable structure controller (DVSC) is proposed for vector controlled induction motor position control. The variable structure control (VSC) which guarantees accuracy and robustness in nonlinear control system is developed in discrete time domain for applying to real servo system. Furthermore, the load torque observer is introduced to reduce chattering problem. The computer simulation results are presented to verify the proposed control scheme.

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A Model Reference Variable Structure Control based on a Neural Network System Identification for an Active Four Wheel Steering System

  • Kim, Hoyong;Park, Yong-Kuk;Lee, Jae-Kon;Lee, Dong-Ryul;Kim, Gi-Dae
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.142-155
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    • 2000
  • A MIMO model reference control scheme incorporating the variable structure theory for a vehicle four wheel steering system(4WS) is proposed and evaluated for a class of continuous-time nonlinear dynamics with known or unknown uncertainties. The scheme employs an neural network to identify the plant systems, where the neural network estimates the nonlinear dynamics of the plant. By the Lyapunov direct method, the algorithm is proven to be globally stable, with tracking errors converging to the neighborhood of zero. The merits of this scheme is that the global system stability is guaranteed and it is not necessary to know the exact structure of the system. With the resulting identification model which contains the neural networks, it does not need higher degrees of freedom vehicle model than 3 degree of freedom model. Th proposed scheme is applied to the active four wheel system and shows the validity is used to investigate vehicle handing performances. In simulation of the J-turn maneuver, the reduction of yaw rate overshoot of a typical mid-size car improved by 30% compared to a two wheel steering system(2WS) case, resulting that the proposed scheme gives faster yaw rate response and smaller side angle than the 2WS case.

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Performance characteristics of a vehicle active suspension system with an optimal variable structure controller (최적 가변구조제어기를 갖는 차량 능동 현가시스템의 성능특성에 관한 연구)

  • 김주용;장효환
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1161-1166
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    • 1993
  • The performances of a vehicle active suspension system with an optimal variable structure controller are compared to those of passive suspension system and active suspension systems with sky-hook and optimal controllers. The quater car model has a 2 DOF which accounts for vertical motions of a sprung and a unsprung masses. The transient responses are analyzed when a vehicle passing through a bump with a constant speed and the frequency responses are analyzed for white noise input at wheel. Particulary, RMS responses are also analyzed. It is shown that the optimal variable structure controller gives better performance of the vehicle active suspensio system than an optimal and a sky-hook controller.

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Variable Structure Control for a System with Mismatched Disturbances (입력과 매칭되지 않는 외란을 갖는 시스템에 대한 가변구조제어)

  • Choi, Yun-Jong;Park, Poo-Gyeon
    • Proceedings of the KIEE Conference
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    • pp.149-151
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    • 2007
  • For several decades, VSC has gained much attention as one of the useful design tools for handling the practical system with uncertainties or disturbances. Generally, the disturbances in the matching condition can be perfectly rejected via VSC; however, these in the mismatching condition are known to be hardly rejected. There have been some trials on it, in which the resulting controls in fact belong to the class of robust control guaranteeing disturbance ${\gamma}$-attenuation. Therefore, in this paper, we propose a new Variable Structure Control (VSC) for a system with mismatched disturbances. The proposed controller is composed of linear and nonlinear parts; the former plays a role in stabilizing the system and the latter takes care of attenuating the disturbances. The main contribution is to introduce the concept of switching-zone, rather than switching-surface, that is designed through piece-wise Lyapunov functions. The resulting non-convex conditions are formulated with an iterative linear programming algorithm, which provides an excellent performance of almost rejecting the disturbances.

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A Robust Global Exponential Stabilization of Uncertain Affine MIMO Nonlinear Systems with Mismatched Uncertainties by Multivariable Sliding Mode Control (다변수 슬라이딩 모드 제어에 의한 부정합조건 불확실성을 갖는 다입출력 비선형 시스템의 강인그로벌 지수 안정화)

  • Lee, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.9
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    • pp.1754-1760
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    • 2011
  • In this paper, a systematic design of a robust nonlinear multivariable variable structure controller based on state dependent nonlinear form is presented for the control of MIMO uncertain affine nonlinear systems with mismatched uncertainties and matched disturbance. After a MIMO uncertain affine nonlinear system is represented in the form of state dependent nonlinear system, a systematic design of a robust nonlinear variable structure controller is presented. To be linear in the closed loop resultant dynamics, the linear sliding surface is applied. A corresponding diagonalized control input is proposed to satisfy the closed loop global exponential stability and the existence condition of the sliding mode on the linear sliding surface, which will be investigated in Theorem 1. Through a design example and simulation study, the usefulness of the proposed controller is verified.

Digital Variable Structure Control for a Hot Water Heating System (온수나방 시스템의 디지틀 가변구조제어)

  • 안병천;장효환
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.8 no.1
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    • pp.65-75
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    • 1996
  • A pilot plant, which is simplified the hot water heating control system of a large scale residential building, is used to investigate the effects of control methods and operating conditions on the system performance and to compare control characteristics. Digital variable structure controller(DVSC) and digital PI controller are implemented to control the speed of the circulating pump for the pilot plant using PC. For the DVSC, a control algorithm is suggested, which using a nonlinear sliding surface and a PID sliding surface outside and inside of output error boundary layer, respectively. Smith predictor algorithm is used for the compensation of long dead time. The suggested DVSC yields improved control performance compared with existing DVSC using linear sliding surface only. the system responses with the suggested DVSC shows good responses without overshoot for various operating conditions and robust under external disturbances compared with digital PI controller.

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Variable Structure Control for Discrete-time Nonlinear Systems

  • Han, So-Hee;Cho, Byung-Sun;Park, Kang-Bak
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1414-1417
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    • 2003
  • In this paper, sliding mode controller for discrete-time nonlinear systems with uncertainties and disturbances are proposed. The concept of time-delay control (TDC) which consists of estimating the uncertain dynamics of the system through past observations of the system response is used. The proposed controller guarantees that the closed-loop system states are globally uniformly ultimately bounded (GUUB). It is also shown that the closed-loop system states are globally uniformly asymptotically stable (GUAS) if uncertainties are constant.

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Actuator and load test system development for continuous variable thruster (연속가변 추력기용 구동장치 및 부하시험장비 개발)

  • Kim, Namjin;Kim, Hyoungkwon;Park, Hyunho;Lim, Jinwan;Suh, Suhkhoon;Park, Iksoo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.401-405
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    • 2017
  • Continuous variable thrusters require precise thrust control to change the position or attitude of the aircraft and to control the pressure inside the combustion chamber. For this purpose, the thrust is adjusted by moving the pintle structure near the nozzle neck inside the combustion chamber by moving the pintle structure forward and backward, and the actuator is used to move the pintle structure. In this paper, we developed a actuator system for continuous variable thruster and load test system to simulate the load under operating conditions. Also, the performance test of the actuator was performed using the developed load test system

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Design of nonlinear variable structure controller using differential geometric methods (미분기하학 방법을 이용한 비선형 가변구조 제어기 설계)

  • 함철주;함운철
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1227-1233
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    • 1993
  • In this paper we present the differential geometric approach for the analysis and design of sliding modes in nonlinear variable structure feedback systems. We also design the robust controller for the nonlinear system using variable structure control theory on the basis of differential geometric methods and feedback linearization applying Min-Max control based on the Lyapunov second method. The robustness against parameter uncertainties for robot manipulators with flexible joint is considered. Simulation results are presented and show the advantage of the proposed nonlinear control method.

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Variable structure control of chaotic systems

  • Choi, Changkyu;Lee, Ju-Jang;Sugisaka, Masanori
    • 제어로봇시스템학회:학술대회논문집
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    • pp.505-510
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    • 1994
  • To prevent the stable states from the complex dynamics, the global behavior of the overall system must be considered. Thus, indirect adaptive scheme might result in needless responses. Discrete-time variable structure controllers for a well-known logistic map are designed for two deferent sliding hyperplanes. Impulse disturbances are fully rejected by tile virtue of discrete-time variable structure control(DVSC). A numerical example is given to illustrate the effectless of the DVSC.

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