• Title, Summary, Keyword: variable structure system

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A Robust Variable Structure Controller for the Mixed Tracking Control of Robot Manipulators (로봇 메니플레이터의 혼합 추적 제어를 위한 강인 가변구조제어기)

  • Lee, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.10
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    • pp.1908-1913
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    • 2010
  • In this paper, a robust variable structure tracking controller is designed for the mixed tracking control of highly nonlinear rigid robot manipulators for the first time. The mixed control problem under consideration is extended from the basic tracking problem, with the different initial condition of both the planned trajectory and link of robots. This control problem in robotics is not addressed to until now. The tracking accuracy to the sliding trajectory after reaching is analyzed. The stability of the closed loop system is investigated in detail in Theorem 2. The results of Theorem 2 provide the stable condition for control gains. Combing the results of Theorem 1 and Theorem 2 gives rise to possibility of designing the improved variable structure tracking controller to guarantee the tracking error from the determined sliding trajectory within the prescribed accuracy after reaching. The usefulness of the algorithm has been demonstrated through simulation studies on the mixed tracking control of a two.link robot under parameter uncertainties and payload variations.

Estimation of the Asymptotic Stability Region for the Uncertain Variable Structure Systems with Bounded Controllers (크기가 제한된 제어기를 갖는 가변구조제어 시스템의 점근 안정 영역 추정)

  • 최한호;국태용
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.8
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    • pp.616-622
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    • 2003
  • This paper deals with the problem of estimating the asymptotic stability region(ASR) of uncertain variable structure systems with bounded controllers. Using linear matrix inequalities(LMIs) we estimate the ASR and show the exponential stability of the closed-loop control system in the estimated ASR. We give a simple LMI-based algorithm to get estimates of the ASR. We also give a synthesis algorithm to design a switching surface which will make the estimated ASR big. Finally, we give numerical examples in order to show that our method can give better results than the previous ones for a certain class of uncertain variable structure systems with bounded controllers.

Position Control of a Hydraulic System Subjected to Disturbances Using a Variable Structure Controller (가변구조제어기를 이용한 외란을 받는 유압시스템의 위치제어)

  • 박근석;김형의
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.10
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    • pp.915-921
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    • 2004
  • In this paper, a variable structure controller(VSC) is used to control the position of the hydraulic servo system subjected to unknown disturbances. The system consists of two cylinders, which connected in series. One cylinder executes position control, the other executes force control to generate disturbances. In order to control each cylinder, interaction must be considered between two cylinders because two cylinders are connected in series. Therefore, the controller is designed regarding interaction between two cylinders as disturbances. Performance of the proposed controller was verified through experiments and compared to PID controller. The experiments showed that the proposed controller had a good performance and robustness.

Fuzzy Variable Structure Control of Wheel-Driven Inverted Pendulum (바퀴구동 도립진자에 대한 퍼지 가변구조제어)

  • Yoo Byung-Kook
    • Journal of the Institute of Convergence Signal Processing
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    • v.5 no.4
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    • pp.301-307
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    • 2004
  • This paper suggests a fuzzy variable structure control scheme for Takagi-Sugeno(T-S) fuzzy model and presents the attitude control of the wheel-driven inverted pendulum(WDIP) based on the proposed control algorithm. The proposed controller is designed based on the T-S fuzzy modeling of nonlinear system and the unification of gain matrices in linear subsystems that constitute the overall fuzzy model. The uncertainties generated in the gain matrix unifying procedure can be interpreted as the input disturbances of the conventional variable structure control. These unifying disturbances can be resolved by using the robustness property of the conventional variable structure system. Design example for wheel-driven inverted pendulum demonstrates the utility and validity of the proposed control scheme.

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A study on the variable structure control method including robot operational condition (로보트 운용조건을 포함한 가변구조 제어방식에 관한 연구)

  • 이홍규;이범희;최계근
    • 제어로봇시스템학회:학술대회논문집
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    • pp.72-75
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    • 1988
  • Due to the fact that the set point regulation scheme by the variable structure control method concerns only the initial and final locations of a manipulator, many constraints may exist in the application of path tracking with obstracle avoidance. The variable structure parameter should be selected in the trajectory planning step by satisfying the constraints of the travel time and the path deviations This paper presents the selection algorithm of the variable structure parameters with the constraints of the system dynamics and the travel time and the path deviation. This study makes unify the trajectory planning and tracking control using the variable structure control method.

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BLDC Motor Position Control by Variable Structure Control with Evolution Strategy (Evolution Strategy를 이용한 가변구조제어기의 BLDC motor 위치제어)

  • Kim, Hyun-Sik;Park, Jin-Hyun;Choi, Young-Kiu
    • Proceedings of the KIEE Conference
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    • pp.655-657
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    • 1995
  • Variable Structure Controller is well known to be a robust controller. Recently, Evolution Strategy is used as a effective search algorithm. In this paper, we propose a Variable Structure Controller combined with Evolution Strategy. Evolution Strategy is used to estimate the unknown parameters, the control gain and the thickness of saturation function boundary layer of Variable Structure Controller. From the experiment, we found the proposed Variable Structure Controller shows accurate tracking ability and robust performance in the BLOC motor position control system.

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A Study on the Path Deviation of the Robot System by Variable Structure Control (가변구조 제어에 의한 로보트 시스템의 경로 이탈에 관한 연구)

  • 이홍규;이범희;최계근
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.12
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    • pp.1601-1609
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    • 1988
  • In the control of the robotic manipulators, the variable structure control method for the set point Regualation has an advantage of the insensitivity about parameter variations and disturbances. When the robotic manipulatores are controlled by a point-to-point scheme, no path constraint is considered. Thus, the variable structure control method will be effectively applied only if the trajectory of the robot hand is estimated precisely. In this paper, the joint trajectories in the joint space and the hand trajectory in the cartesian space are calculated by the variable structure control method, and an algorithm is suggested to elaborate the deviation error of the robot hand from a straight line path. The result of this study will become a base of the effective path planning about robotic manipulators with the variable structure control concept.

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A study on the position control of an electro-hydraulic servomechanism using variable structure system (가변구조를 이용한 전기-유압서어보계의 위치제어에 관한 연구)

  • 허순영;권기수;하석훈;이진걸
    • 제어로봇시스템학회:학술대회논문집
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    • pp.299-304
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    • 1988
  • This paper describes the application of the variable structure control(VSC) concept for the position control of electro-hydraulic servomtor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state surface with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems.

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Position control of DC Motor using Variable Structure (가변구조를 이용한 직류전동기의 위치제어)

  • Li, Sun-Jong;Nam, Moon-Hyon;Kim, Lark-Kyo
    • Proceedings of the KIEE Conference
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    • pp.337-341
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    • 1989
  • This theory has fast response and low overshoot by transforming its structure and this system may have new character which did not appear in this system. The VSS system transform its structure by switching logic. Then, the state trajectory is to sliding along the switching line to the phase-plane orgin. The phase trajectory is known as the sliding mode of this controller. This paper performed position control in the theory and analysised the change in variable loads.

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A Static Output Feedback Integral Variable Structure Controller for Uncertain Systems with Unmatched System Matrix Uncertainty (부정합 시스템 행렬 불확실성을 갖는 시스템을 위한 정적 출력 궤환 적분 가변 구조 제어기)

  • Lee, Jung-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.2
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    • pp.411-416
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    • 2010
  • In this paper, an integral variable structure static output feedback controller with an integral-augmented sliding surface is designed for the improved robust control of a uncertain system under unmatched system uncertainty and matched input matrix uncertainty and disturbance satisfying some conditions. To effectively remove the reaching phase problems, an output dependent integral augmented sliding surface is proposed. Its equivalent control and ideal sliding mode dynamics are obtained. The previous some limitations is overcome in this systematic design. A stabilizing control with the closed loop exponential stability is designed for all unmatched system matrix uncertainties and proved together with the existence condition of the sliding mode on S=0. To show the usefulness of the algorithm, a design example and computer simulations are presented.