• Title/Summary/Keyword: Lipschitz nonlinear systems

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LIPSCHITZ AND ASYMPTOTIC STABILITY FOR PERTURBED NONLINEAR DIFFERENTIAL SYSTEMS

  • Goo, Yoon Hoe
    • The Pure and Applied Mathematics
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    • v.21 no.1
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    • pp.11-21
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    • 2014
  • The present paper is concerned with the notions of Lipschitz and asymptotic stability for perturbed nonlinear differential system knowing the corresponding stability of nonlinear differential system. We investigate Lipschitz and asymtotic stability for perturbed nonlinear differential systems. The main tool used is integral inequalities of the Bihari-type, in special some consequences of an extension of Bihari's result to Pinto and Pachpatte, and all that sort of things.

Robust Reduced Order State Observer for Lipschitz Nonlinear Systems (Lipschitz 비선형 시스템의 강인 저차 상태 관측기)

  • Lee, Sung-Ryul
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.8
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    • pp.837-841
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    • 2008
  • This paper presents a robust reduced order state observer for a class of Lipschitz nonlinear systems with external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level. Finally, a numerical example is provided to verify the proposed design method.

Reduced Order Observer Design for One-Sided Lipschitz Nonlinear Systems (단측 Lipschitz 비선형시스템의 축차 관측기 설계)

  • Lee, Sungryul
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.4
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    • pp.281-284
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    • 2013
  • This paper describes a reduced observer design problem for one-sided Lipschitz nonlinear systems which are considered as a generalization of Lipschitz systems. The sufficient conditions to ensure the existence of reduced order observer are provided by using linear matrix inequalities. Moreover, it is shown that existence conditions of reduced order observer can be obtained from sufficient conditions on the existence of full order observer. As a result, this fact implies that the existence of full order observer for one-sided Lipschitz systems guarantees that of reduced order observer. Finally, a simulation example is given to verify the validness of the proposed design.

ON STABILITY OF NONLINEAR NONAUTONOMOUS SYSTEMS BY LYAPUNOV'S DIRECT METHOD

  • Park, Jong-Yeoul;Phat, Vu-Ngoc;Jung, Il-Hyo
    • Journal of the Korean Mathematical Society
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    • v.37 no.5
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    • pp.805-821
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    • 2000
  • The paper deals with asymtotic stabillity of nonlinear nonautinomous systems by Lyapunov's direct method. The proposed Lyapunov-like function V(t, x) needs not be continuous in t and Lipschitz in x in a Banach space. The class of systems considered is allowed to be nonautonomous and infinite-dimensional and we relax the boundedness, the Lipschitz assumption on the system and the definite decrescent condition on the Lyapunov function.

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Robust State Observer for Lipschitz Nonlinear Systems with Time Delay (시간 지연을 갖는 Lipschitz 비선형 시스템의 강인 상태 관측기)

  • Lee, Sung-Ryul
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.11
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    • pp.1089-1093
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    • 2008
  • This paper presents a robust state observer design for a class of Lipschitz nonlinear systems with time delay and external disturbance. Sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level in spite of the existence of time delay. Finally, a numerical example is provided to verify the proposed design method.

Design of observer for a class of Lipschitz nonlinear systems

  • Choi, H.L.;Lim, J.T.
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2099-2101
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    • 2005
  • The problem of observer design for a class of Lipschitz nonlinear systems is considered. We propose a new observer design method which takes into account the structure of perturbed nonlinear terms with a scaling factor ${\epsilon}$. An example is provided to demonstrate the usefulness of our result over the existing method.

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Robust State Observer for Lipschitz Nonlinear Systems with Time Delay (시간 지연을 갖는 Lipschitz 비선형 시스템의 강인 상태 관측기)

  • Lee, Sung-Ryul
    • Proceedings of the KIEE Conference
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    • 2008.04a
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    • pp.207-208
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    • 2008
  • This paper presents a robust state observer design for a class of Lipschitz nonlinear systems with time delay and external disturbance. A sufficient conditions on the existence of the proposed observer are characterized by linear matrix inequalities. It is also shown that the proposed observer design can reduce the effect on the estimation error of external disturbance up to the prescribed level in spite of the existence of time delay. Finally, a numerical example is provided to verify the proposed design method.

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Design of a Nonlinear Observer for Mechanical Systems with Unknown Inputs (미지 입력을 가진 기계 시스템을 위한 비선형 관측기 설계)

  • Song, Bongsob;Lee, Jimin
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.6
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    • pp.411-416
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    • 2016
  • This paper presents the design methodology of an unknown input observer for Lipschitz nonlinear systems with unknown inputs in the framework of convex optimization. We use an unknown input observer (UIO) to consider both nonlinearity and disturbance. By deriving a sufficient condition for exponential stability in the linear matrix inequality (LMI) form, existence of a stabilizing observer gain matrix of UIO will be assured by checking whether the quadratic stability margin of the error dynamics is greater than the Lipschitz constant or not. If quadratic stability margin is less than a Lipschitz constant, the coordinate transformation may be used to reduce the Lipschitz constant in the new coordinates. Furthermore, to reduce the maximum singular value of the observer gain matrix elements, an object function to minimize it will be optimally designed by modifying its magnitude so that amplification of sensor measurement noise is minimized via multi-objective optimization algorithm. The performance of UIO is compared to a nonlinear observer (Luenberger-like) with an application to a flexible joint robot system considering a change of load and disturbance. Finally, it is validated via simulations that the estimated angular position and velocity provide true values even in the presence of unknown inputs.