• Title/Summary/Keyword: Uncertain systems

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Some Properties of Complex Uncertain Process

  • You, Cuilian;Xiang, Na
    • Industrial Engineering and Management Systems
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    • v.15 no.2
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    • pp.143-147
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    • 2016
  • Uncertainty appears not only in real quantities but also in complex quantities. Complex uncertain process is essentially a sequence of complex uncertain variables indexed by time. In order to describe complex uncertain process, a formal definition of complex uncertain distribution is given in this paper, as well as the concepts of independence and variance. In addition, some properties of complex uncertain integral are presented.

Intelligent Digital Redesign of Uncertain Nonlinear Systems Using Power Series (Power Series를 이용한 불확실성을 포함된 비선형 시스템의 지능형 디지털 재설계)

  • Sung, Hwa-Chang;Joo, Young-Hoon;Park, Jin-Bae;Kim, Do-Wan
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.496-498
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    • 2005
  • This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also by using the power series, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMIs).

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Intelligent Digital Redesign of Uncertain Nonlinear Systems : Global approach (불확실성이 포함된 비선형 시스템에 대한 전역적 접근의 지능형 디지털 재설계)

  • Sung Hwachang;Joo Younghoon;Park Jinbae;kim Dowan
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2005.11a
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    • pp.95-98
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    • 2005
  • This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent the complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also by using the power series, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete -time system have proper reason. Sufficiently conditions for the global state -matching of the digitally controlled system are formulated in terms of linear matrix inequalities (LMls). Finally, we prove the effectiveness and stabilization of the proposed intelligent digital redesign method by applying the chaotic Lorentz system.

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Design of robust gain scheduling controllers in uncertain nonlinear systems

  • Lee, Seon-Ho;Lim, Jong-Tae
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.231-234
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    • 1996
  • This paper considers the output regulation problems on uncertain systems. Using NR-estimator(on-line), a family of equilibrium points for the uncertain system is computed. The state variables of the closed loop system track the average value of the obtained equilibrium manifold by dynamic state feedback control.

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Design of a Continuous Adaptive Robust Control Estimating the Upper Bound of the Uncertainties using Fredholm Integral Formulae (Fredholm 적분식을 이용하여 불확실성의 경계치를 추정하는 적응강인제어기 설계)

  • 유동상
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.4
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    • pp.207-211
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    • 2004
  • We consider a class of uncertain nonlinear systems containing the uncertainties without a priori information except that they are bounded. For such systems, we assume that the upper bound of the uncertainties is represented as a Fredholm integral equation of the first kind and we propose an adaptation law that is capable of estimating the upper bound. Using this adaptive upper bound, a continuous robust control which renders uncertain nonlinear systems uniformly ultimately bounded is designed.

A computed-error-input based learning scheme for multi-robot systems

  • Kuc, Tae-Yong
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.518-521
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    • 1995
  • In this paper, a learning control problem is formulated for cooperating multiple-robot manipulators with uncertain system parameters. The commonly held object is also assumed to be unknown and the multiple-robots themselfs experience uncertain operating conditions such as link parameters, viscous friction parameters, suctions, actuator bias, and etc. Under these conditions, the learning controllers designed for learning of uncertain parameters and robot control inputs for multiple-robot systems are shown to drive the multiple-robot manipulators to follow the desired Cartesian trajectory with the desired internal forces to the unknown object.

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A guaranteed cost LQ regulator in the presence of parameter uncertainties (파라미터가 불확정된 경우의 guaranteed cost LQ 레귤레이터)

  • 이정문;최계근
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.367-369
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    • 1986
  • Guaranteed cost control is a method applicable to a class of systems with uncertain parameters that guarantees an upper bound of the cost functional. This paper is concerned with a matrix decomposition technique used to yield a reasonable upper bound of the cost functional for a finite-time LQ regulator problem. The uncertain linear systems dealt with in this paper are described by a set of state equations of single-input phase-variable canonical form which contain unknown but bounded uncertain parameters.

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Delay-dependent Robust Stability of Uncertain Dynamic Systems with Time-varying Delays (시변 지연이 존재하는 불확실 동적 시스템의 지연 의존 강인 안정성)

  • Kwon, Oh-Min;Park, Ju-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.1
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    • pp.181-186
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    • 2009
  • In this paper, the stability analysis for uncertain dynamic systems with time-varying delays is considered. By constructing a new Lyapunov functional, a novel stability criterion is established in terms of linear matrix inequalities (LMIs). Two numerical examples are carried out to support the effectiveness of the proposed method.

Some Sufficient Conditions for Output Regulation of Uncertain Nonlinear Systems (불확실 비선형 시스템의 출력제어를 위한 충분조건)

  • 하인중;최종호;고명삼
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.2
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    • pp.162-167
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    • 1988
  • In this note, we present some sufficient conditions on the structure of modelling uncertainties for output regualtion of uncertain systems. It turns out that these conditions include as special cases the ordinary matching conditions for stage regulation of uncertain systems and the disturbance decoupling condition. the previous restrictions on the structure of modelling uncertainties can be considerably relaxed in the case of output regulation. The significance of out result is illuminated through a simple example.

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New Robust $H_{\infty}$ Performance Condition for Uncertain Discrete-Time Systems

  • Zhai, Guisheng;Lin, Hai;Kim, Young-Bok
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.322-326
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    • 2003
  • In this paper, we establish a new robust $H_{\infty}$ performance condition for uncertain discrete-time systems with convex polytopic uncertainties. We express the condition as a set of linear matrix inequalities (LMIs), which are used to check stability and $H_{\infty}$ disturbance attenuation level by a parameter-dependent Lyapunov matrix. We show that the new condition provides less conservative result than the existing ones which use single Lyapunov matrix. We also show that the robust $H_{\infty}$ state feedback design problem for such uncertain discrete-time systems can be easily dealt with using the approach. The key point in this paper is to propose a kind of decoupling between the Lyapunov matrix and the system matrices in the parameter-dependent matrix inequality by introducing one new matrix variable.

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