• 제목, 요약, 키워드: linear time-varying system

검색결과 284건 처리시간 0.043초

시변 선형 시스템의 웨이브렛망 근사화와 가중치의 학습 (Wavelet network approximation and coefficient learning of linear-time-varying system)

  • 이영석;김동옥;서보혁
    • 제어로봇시스템학회:학술대회논문집
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    • pp.728-731
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    • 1997
  • This paper discusses approximation modelling of discrete-time linear time-varying system(LTVS). The wavelet transform is considered as a tool for representing and approximating a LTVS. The joint time-frequency properties of wave analysis are appropriate for describing the LTVS. Simulation results is included to illustrate the potential application of the technique.

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시변시스템을 위한 RBF 신경망 기반의 QFT 파라미터계획 제어기법과 alt일 제어시스템에의 적용 (RBF Network Based QFT Parameter-Scheduling Control Design for Linear Time-Varying Systems and Its Application to a Missile Control System)

  • 임기홍;최재원
    • 제어로봇시스템학회:학술대회논문집
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    • pp.199-199
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    • 2000
  • Most of linear time-varying(LTV) systems except special cases have no general solution for the dynamic equations. Thus, it is difficult to design time-varying controllers in analytic ways, and other control design approaches such as robust control have been applied to control design for uncertain LTI systems which are the approximation of LTV systems have been generally used instead. A robust control method such as quantitative feedback theory(QFT) has an advantage of guaranteeing the stability and the performance specification against plant parameter uncertainties in frozen time sense. However, if these methods are applied to the approximated linear time-invariant(LTI) plants which have large uncertainty, the designed control will be constructed in complicated forms and usually not suitable for fast dynamic performance. In this paper, as a method to enhance the fast dynamic performance, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks for LTV systems with bounded time-varying parameters.

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Tracking control of variable stiffness hysteretic-systems using linear-parameter-varying gain-scheduled controller

  • Pasala, D.T.R.;Nagarajaiah, S.;Grigoriadis, K.M.
    • Smart Structures and Systems
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    • v.9 no.4
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    • pp.373-392
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    • 2012
  • Tracking control of systems with variable stiffness hysteresis using a gain-scheduled (GS) controller is developed in this paper. Variable stiffness hysteretic system is represented as quasi linear parameter dependent system with known bounds on parameters. Assuming that the parameters can be measured or estimated in real-time, a GS controller that ensures the performance and the stability of the closed-loop system over the entire range of parameter variation is designed. The proposed method is implemented on a spring-mass system which consists of a semi-active independently variable stiffness (SAIVS) device that exhibits hysteresis and precisely controllable stiffness change in real-time. The SAIVS system with variable stiffness hysteresis is represented as quasi linear parameter varying (LPV) system with two parameters: linear time-varying stiffness (parameter with slow variation rate) and stiffness of the friction-hysteresis (parameter with high variation rate). The proposed LPV-GS controller can accommodate both slow and fast varying parameter, which was not possible with the controllers proposed in the prior studies. Effectiveness of the proposed controller is demonstrated by comparing the results with a fixed robust $\mathcal{H}_{\infty}$ controller that assumes the parameter variation as an uncertainty. Superior performance of the LPV-GS over the robust $\mathcal{H}_{\infty}$ controller is demonstrated for varying stiffness hysteresis of SAIVS device and for different ranges of tracking displacements. The LPV-GS controller is capable of adapting to any parameter changes whereas the $\mathcal{H}_{\infty}$ controller is effective only when the system parameters are in the vicinity of the nominal plant parameters for which the controller is designed. The robust $\mathcal{H}_{\infty}$ controller becomes unstable under large parameter variations but the LPV-GS will ensure stability and guarantee the desired closed-loop performance.

입출력 변환을 이용한 선형 시변 시스템의 제어기 설계 (The Controller Design for a Class of Time-Varying Linear System via I/O Transformation)

  • 조도현;이상훈;이종용
    • 전자공학회논문지 IE
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    • v.43 no.3
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    • pp.28-33
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    • 2006
  • 본 논문에서는 선형 시변 시스템에 대하여 입출력 변환을 적용하여 선형 시불변 시스템을 얻기 위한, 입출력 변환의 필요충분조건을 제시한다. 변환된 시스템은 다중 적분기를 갖는 시스템으로 표현되며, 예제를 통하여 제안된 알고리즘을 확인하고, 검토하였다.

입력-상태, 입력-출력 변환을 이용한 선형 시변 시스템의 가제어성, 가관측성 해석 (The Interpreter Controllability and Observability for a Class of Time-varying Linear System via I/S and I/O Transformation)

  • 원영진;이상훈;이종용
    • 전자공학회논문지 IE
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    • v.44 no.3
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    • pp.51-55
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    • 2007
  • 본 논문에서는 선형 시변 시스템에 대하여 입력-상태, 입력-출력 변환을 적용하여 선형 시변 시스템의 가제어성과 가관측성을 해석하고자 한다. 또한 입력-상태, 입력-출력 변환을 통하여 얻어진, 변환된 시스템은 다중 적분기를 갖는 시스템으로 표현되며, 예제를 통하여 제안된 알고리즘을 확인하고, 검토하였다.

시변 시간지연을 가지는 이산 선형 불확실성 시스템에 대한 보장 비용 제어 (Guaranteed Cost Control for Discrete-time Linear Uncertain Systems with Time-varying Delay)

  • 김기태;조상현;이상경;박홍배
    • 전자공학회논문지SC
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    • v.39 no.6
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    • pp.20-26
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    • 2002
  • 본 논문에서는 시변 시간지연을 가지는 이산 선형 불확실성 시스템에 대한 보장 비용 제어문제를 다룬다. 본 논문에서 다루는 불확실성 시스템은 시변 노옴 한정 파라미터 불확실성을 가진다. 모든 허용 가능한 불확실성에 대해 폐루프 시스템이 자승적으로 안정하고 성능을 보장하는 제어기가 존재할 충분조건과 설계방법에 대해 논의한다. 또한, 변수 치환과 Schur 여수정리 등을 이용하여 충분조건을 모든 변수에 대한 선형 행렬 부등식(linear matrix inequality)으로 표현한다.

Design of Autonomous Cruise Controller with Linear Time Varying Model

  • Chang, Hyuk-Jun;Yoon, Tae Kyun;Lee, Hwi Chan;Yoon, Myung Joon;Moon, Chanwoo;Ahn, Hyun-Sik
    • Journal of Electrical Engineering and Technology
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    • v.10 no.5
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    • pp.2162-2169
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    • 2015
  • Cruise control is a technology for automatically maintaining a steady speed of vehicle as set by the driver via controlling throttle valve and brake of vehicle. In this paper we investigate cruise controller design method with consideration for distance to vehicle ahead. We employ linear time varying (LTV) model to describe longitudinal vehicle dynamic motion. With this LTV system we approximately model the nonlinear dynamics of vehicle speed by frequent update of the system parameters. In addition we reformulate the LTV system by transforming distance to leading vehicle into variation of system parameters of the model. Note that in conventional control problem formulation this distance is considered as disturbance which should be rejected. Consequently a controller can be designed by pole placement at each instance of parameter update, based on the linear model with the present system parameters. The validity of this design method is examined by simulation study.

시변 불확실성을 가지는 선형 시스템을 위한 반복 제어 시스템의 설계 (Design of Repetitive Control System for Linear Systems with Time-Varying Uncertainties)

  • 정명진;도태용
    • 제어로봇시스템학회논문지
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    • v.11 no.1
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    • pp.13-18
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    • 2005
  • This paper considers a design problem of the repetitive control system for linear systems with time-varying norm bounded uncertainties. Using the Lyapunov functional for time-delay systems, a sufficient condition ensuring robust stability of the repetitive control system is derived in terms of an algebraic Riccati inequality (ARI) or a linear matrix inequality (LMI). Based on the derived condition, we show that the repetitive controller design problem can be reformulated as an optimization problem with an LMI constraint on the free parameter.

STABILITY AND CONSTRAINED CONTROLLABILITY OF LINEAR CONTROL SYSTEMS IN BANACH SPACES

  • Phat, Vu-Ngoc;Park, Jong-Yeoul;Jung, Il-Hyo
    • 대한수학회지
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    • v.37 no.4
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    • pp.593-611
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    • 2000
  • For linear time-varying control systems with constrained control described by both differential and discrete-time equations in Banach spaces was give necessary and sufficient conditions for exact global null-controllability. We then show that for such systems, complete stabilizability implies exact null-controllability.

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QFT Parameter-Scheduling Control Design for Linear Time- varying Systems Based on RBF Networks

  • Park, Jae-Weon;Yoo, Wan-Suk;Lee, Suk;Im, Ki-Hong;Park, Jin-Young
    • Journal of Mechanical Science and Technology
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    • v.17 no.4
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    • pp.484-491
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    • 2003
  • For most of linear time-varying (LTV) systems, it is difficult to design time-varying controllers in analytic way. Accordingly, by approximating LTV systems as uncertain linear time-invariant, control design approaches such as robust control have been applied to the resulting uncertain LTI systems. In particular, a robust control method such as quantitative feedback theory (QFT) has an advantage of guaranteeing the frozen-time stability and the performance specification against plant parameter uncertainties. However, if these methods are applied to the approximated linear. time-invariant (LTI) plants with large uncertainty, the resulting control law becomes complicated and also may not become ineffective with faster dynamic behavior. In this paper, as a method to enhance the fast dynamic performance of LTV systems with bounded time-varying parameters, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks.