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Aberkane S.,Nancy Research Center for Automatic Control
Systems and Control Letters | Year: 2011

This paper deals with the problem of stochastic stability analysis and control synthesis of a class of Markovian jump linear systems (MJLS) with time-varying transition probabilities (TPs) in the discrete-time domain. The time-varying character is considered to be in a polytopic sense. The approach followed in this note is based on the use of a parameter dependent stochastic Lyapunov function. We give a stability condition in terms of a linear matrix inequality (LMI) feasibility problem. The obtained results are illustrated in a numerical example. © 2010 Elsevier B.V. Source


Postoyan R.,Nancy Research Center for Automatic Control | Nesic D.,University of Melbourne
Automatica | Year: 2012

We consider a general class of nonlinear reduced-order observers and show that the global asymptotic convergence of the observation error in the absence of network-induced constraints is maintained for the emulated observer semiglobally and practically (with respect to the maximum allowable transmission interval) when system measurements are sent through a communication channel. Networks governed by a Lyapunov uniformly globally asymptotically stable protocol are investigated. Our results can be used to synthesize various observers for networked control systems for a range of network configurations, as we illustrate it by considering classes of immersion and invariance observers which include the circle-criterion observers. © 2012 Elsevier Ltd. All rights reserved. Source


Chadli M.,University of Picardie Jules Verne | Darouach M.,Nancy Research Center for Automatic Control
Automatica | Year: 2012

This paper concerns the bounded real lemma for discrete-time descriptor systems. A new formulation of the bounded real lemma for these systems is given. It extends the recent results presented in Zhang, Xia, and Shi (2008) and gives necessary and sufficient conditions in strict LMI (linear matrix inequality) which is more suitable for the control design than those presented in Zhang, Xia, and Shi (2008). An application to the H∞ control design is given. A numerical example is presented to show the applicability of our approach. © 2011 Elsevier Ltd. All rights reserved. Source


Boukhobza T.,Nancy Research Center for Automatic Control
International Journal of Systems Science | Year: 2010

This article deals with the problem of additional sensor location in order to recover the observability of any given part of the state and unknown input for structured linear systems. The proposed method is based on a graph-theoretic approach and assumes only the knowledge of the system's structure. We first provide graphical and necessary sufficient conditions for the generic observability of any given part of the state and input. Then, we study the number and location of additional sensors in order to satisfy the latter conditions. On the one hand, we provide necessary requirements to be satisfied by these additional sensors. On the other hand, we give other sufficient simple conditions allowing us to add a number, which is guaranteed to be minimal, of sensors to ensure the observability of any given part of the state and unknown input. © 2010 Taylor & Francis. Source


Darouach M.,Nancy Research Center for Automatic Control
Systems and Control Letters | Year: 2012

This paper is concerned with the design of functional observers for linear time-invariant descriptor systems. Contrary to the functional observers considered for the standard systems in Darouach [8], where the order of these observers is equal to the dimension r of the functional to be estimated, in this paper the order can be of dimension different of that of this functional. When this order is equal to the dimension of the functional and the system is in a standard form, the presented design method becomes that of Darouach [8]. It also generalizes the existing results for descriptor systems. The approach is based on the new definition of partial impulse observability. Sufficient conditions for the existence and stability of these observers are given. Continuous time and discrete time systems are considered. Two numerical examples are given to illustrate our approach. © 2011 Elsevier B.V. All rights reserved. Source

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