• Title/Summary/Keyword: saturation controller

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Static anti-reset windup method for saturating control systems with multiple controllers and multiloop configuration (다중 제어기 및 다중 루우프로 구성된 포화 제어 시스템의 정적 리셋 와인드엎 방지 방법)

  • Park, Jong-Koo;Choi, Chong-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.2 no.4
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    • pp.248-256
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    • 1996
  • This paper presents an anti-reset windup (ARW) compensation method for saturating control systems with multiple controllers and/or multiloop configuration. The proposed ARW method is motivated by the concept of equilibrium point. The design parameters of the ARW scheme is derive explicitly by minimizing a reasonable performance index. In the event of saturation, the resulting dynamics of the compensated controller reflects the dynamics of the linear closed-loop system. The proposed method guarantees the total stability o fthe resulting control systems under a certain condition. An illustrative example is given to show the effectiveness of the proposed method. The paper is an extension of the results in Park and Choi[10].

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Vibration control of hysteretic base-isolated structures: an LMI approach

  • Pozo, Francesc;Pujol, Gisela;Acho, Leonardo
    • Smart Structures and Systems
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    • v.17 no.2
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    • pp.195-208
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    • 2016
  • Seismic isolation systems are essentially designed to preserve structural safety, prevent occupants injury and properties damage. An active saturated LMI-based control design is proposed to attenuate seismic disturbances in base-isolated structures under saturation actuators. Using a mathematical model of an eight-storied building structure, an active control algorithm is designed. Performance evaluation of the controller is carried out in a simplified model version of a benchmark building system, which is recognized as a state-of-the-art model for numerical experiments of structures under seismic perturbations. Experimental results show that the proposed algorithm is robust with respect to model and seismic perturbations. Finally, the performance indices show that the proposed controller behaves satisfactorily and with a reasonable control effort.

On the stabilization of linear discrete time systems subject to input saturation

  • Choi, Jinhoon
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1770-1773
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    • 1997
  • In this paper, a linear discrete time system subject to the input saturatioin is shown to be exponentially stabilizable on any compact subset of the constrained asymptotically stabilizable set by a linear periodic variable structure controller. We also establish tat any neutrally stable system subject to the input saturation can be globally asymptotically stabilizable via linear feedback.

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Current controller using the modified delay compensator under the control input saturation (제어전압제한을 이용한 지연시간보상 전류제어기)

  • 이진우;강병희;백상기;민종진
    • Proceedings of the KIPE Conference
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    • 1997.07a
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    • pp.341-344
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    • 1997
  • This paper suggests the modified delay compensation scheme under the control input saturation in order to improve the control performance. This scheme uses the real estimated control input instead of the direct command control input. The simulation results show that this scheme can improve the current control performance under the delay time and the limited control input.

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Fuzzy sliding mode controllers for high performance control of AC servo motors (AC 서보 모터의 고성능 제어를 위한 퍼지 슬라이딩 모드 제어기)

  • 김광수;조동일
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.732-735
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    • 1997
  • Variable Structure Controller(VSC) is usually known to have robustness to bounded exogenous disturbances. The robustness is attributed to the discontinuous term in the control input. However, this discontinuous term also causes an undesirable effect called chattering. To alleviate chattering, a hybrid controller consisting of VSC and Fuzzy Logic Controller(FLC) is proposed, which belongs to the category of Fuzzy Sliding Mode Controller(FSMC). The role of FLC in FSMC is to replace a fixed gain of a discontinuous term with a time-varying one based on a specified rule base. The characteristics of proposed controller are shown to be similar to those of VSC with a saturation function instead of sign function. The only remarkable difference is the nonlinearity whose form can be adjusted by free parameters, normalize gain, denormalize gain, and membership functions. Applied to AC servo motor, the proposed controller is compared with VSC in a regulation problem as well as a speed tracking problem. The simulation results show a substantial chatter reduction.

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An FNN based Adaptive Speed Controller for Servo Motor System

  • Lee, Tae-Gyoo;Lee, Je-Hie;Huh, Uk-Youl
    • Journal of Electrical Engineering and information Science
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    • v.2 no.6
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    • pp.82-89
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    • 1997
  • In this paper, an adaptive speed controller with an FNN(Feedforward Neural Network) is proposed for servo motor drives. Generally, the motor system has nonlinearities in friction, load disturbance and magnetic saturation. It is necessary to treat the nonlinearities for improving performance in servo control. The FNN can be applied to control and identify a nonlinear dynamical system by learning capability. In this study, at first, a robust speed controller is developed by Lyapunov stability theory. However, the control input has discontinuity which generates an inherent chattering. To solve the problem and to improve the performances, the FNN is introduced to convert the discontinuous input to continuous one in error boundary. The FNN is applied to identify the inverse dynamics of the motor and to control the motor using coordination of feedforward control combined with inverse motor dynamics identification. The proposed controller is developed for an SR motor which has highly nonlinear characteristics and it is compared with an MRAC(Model Reference Adaptive Controller). Experiments on an SR motor illustrate te validity of the proposed controller.

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Servo Motor Control by On-Off Controller with Hysterisis (히스테리시스를 갖는 온-오프 제어기에 의한 서보모터의 제어)

  • 김영복;김성환;양주호;정병건
    • Journal of Advanced Marine Engineering and Technology
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    • v.15 no.1
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    • pp.85-95
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    • 1991
  • All physical systems are nonlinear to some degree. The examples are relay, backlash, deadzone, saturation element and so on. In the linear control system design, it is useful method to restrict the nonlinearity to the linearity of system over the operation range. It is worth noting that nonlinearities may be intentionally introduced in to a system. A simple of an intentional non-linearity is the Bang-Bang controller which uses the On-Off relay. In this paper, an angular position servosystem made of a DC servomotor controlled by a microcomputer is discribed. Authors use two methods in the design of controller. The one is linear controller designed by the optimal feedback control theory only and the other is nonlinear controller designed by On-Off relay with optimal feedback control theory. To do the real time control, the controller is designed by using 16bit personal computer and A/D.D/A converter(12bit) is used in order to convert the signal. According to this way, the results from real time control are as follows. 2) Under the On-Off controller with hysterisis the influence of disturbance is considerably smaller than the linerar controller. 3) An increase in the sampling period has a destabilizing effect. 4)In the controller performance, the response time of the On-Off controller is longer than that of the linear controller. To close, we note that the On-Off controller with hysterisis is more attractive than the linear controller in the presence of the input limit.

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Implementation of the Controller for a Stable Walking of a Humanoid Robot Using Improved Genetic Algorithm (개선된 유전 알고리즘 기반의 휴머노이드 로봇의 안정 보행을 위한 제어기 구현)

  • Kong, Jung-Shik;Lee, Eung-Hyuk;Kim, Jin-Geol
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.5
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    • pp.399-405
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    • 2007
  • This paper deals with the controller for a stable walking of a humanoid robot using genetic algorithm. A humanoid robot has instability during walking because it isn't fixed on the ground, and its nonlinearities of the joints increase its instability. If controller isn't robust, the robot may fall down at the ground during walking because of its nonlinearities. To solve this problem, robust controller is required to reduce the effect of nonlinearities and to gain the good tracking performance. In this paper, motion controller that is based on fuzzy-sliding mode controller is proposed. This controller can remove the effect of the saturation by limitation of the input voltage. It also includes compensator for reducing the effect of the nonlinearity by backlash and PI controller improving the tracking performance. In here, genetic algorithm is used for searching the optimal gains of the controller. From the given controller, a humanoid robot can moved more preciously. All the processes are investigated through simulations and are verified experimentally in a real joint system for a humanoid robot.

Design of a Robust Adaptive Backstepping Controller for a Chaos System with Disturbances (외란을 포함한 카오스시스템의 강인 적응 백스테핑 제어기 설계)

  • Hyun, Keun-Ho;Ka, Chool-Hyun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.54 no.3
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    • pp.119-128
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    • 2005
  • In this paper, an robust adaptive backstepping controller is proposed for the chaos system with disturbances. This controller will be applicable to the chaos system of strict-feedback form and utilize the saturation function for decreasing the effect of disturbances derived from unmodelled dynamics and external noise. It shows that backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.

Implementation of the High Performance Unified PID Position Controller for Linear Motor Drive with Easy Gain Ajustment Part II - Gain Adjustment & Application (이득 설계가 간단한 선형전동기 구동용 고성능 통합 PID 위치제어기 구현 제2부: 이득설계 및 응용)

  • Kim, Jun-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.4
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    • pp.195-202
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    • 2002
  • The high performance position controller named 'Unified PID Position Controller'is presented in part 1 of this paper. In part 2, we provide smart gain adjustment methods including the freedom utilizations for rare sensitivity toward the system parameter variation and for increasing the stiffness of the system. Owing to the provided gain tuning strategy, the overall system characteristics can be stabilized without over-shoot phenomena when the system parameter is changed in the rate of from 0.5 to 2∼4. Moreover, for the actual feasibility to the industrial fields, a simple butt effective anti-windup strategy prohibiting the integral component of the PID position controller from saturation is presented too. All of the presented algorithms are verified through the experiment works with commercial linear motor.