Browsing by Author "Xie L."

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H?-filtering for a class of nonlinear time-delay systems
(2002) Mahmoud M.S.; Xie L.; Faculty of Engineering; MSA University; Amer Street; Mesaha Square; Dokki; Egypt; School of Electrical and Electronic Engineering; Nanyang Technological University; Nanyang Avenue; Singapore 639798; Singapore
In this paper, we consider the problem of robust H ?-filtering for a class of uncertain time-delay systems. This calss is nominally linear and has a known cone-bounded, state-dependent nonlinear term. The parametric uncertainty is real time-varying and the state-delay factor is unknown. We design a nonlinear estimator which renders the estimation error dynamics quadratically stable and provides a guaranteed H?-performance of the filtering error for all admissible uncertainties and unknown state-delay. � 2002 Taylor & Francis Ltd.
Passivity Analysis and Synthesis for Uncertain Time-Delay Systems
(Taylor and Francis Inc., 2001) Mahmoud M.S.; Xie L.; Faculty of Engineering; MSA University; Amer Street; Mesaha Square; Dokki; Egypt; Sch. of Elec. and Electron. Eng.; Nanyang Technological University; Nanyang Avenue; Singapore 639798; Singapore
In this paper, we investigate the robust passivity analysis and synthesis problems for a class of uncertain time-delay systems. This class of systems arises in the modelling effort of studying water quality constituents in fresh stream. For the analysis problem, we derive a sufficient condition for which the uncertain time-delay system is robustly stable and strictly passive for all admissible uncertainties. The condition is given in terms of a linear matrix inequality. Both the delay-independent and delay-dependent cases are considered. For the synthesis problem, we propose an observer-based design method which guarantees that the closed-loop uncertain time-delay system is stable and strictly passive for all admissible uncertainties. Several examples are worked out to illustrate the developed theory.
Robust Kalman filtering for discrete state-delay systems
(IEE, Stevenage, United Kingdom, 2000) Mahmoud M.S.; Xie L.; Soh Y.C.; Department of Electrical and Computer Engineering; Kuwait University; Kuwait; Department of Engineering; MSA University; Amer St.; Mesaha Square; Dokki; Egypt; School of Electrical and Electronic Engineering; Nanyang Technological University; Nanyang Avenue; Singapore 639798; Singapore
A robust estimator design methodology has been developed for a class of linear uncertain discrete-time systems. It extends the Kalman filter to the case in which the underlying system is subject to norm-bounded uncertainties and constant state delay. A linear state estimator is constructed via a systematic procedure such that the estimation error covariance is guaranteed to lie within a certain bound for all admissible uncertainties. The solution is given in terms of two Riccati equations involving scaling parameters. A numerical example is provided to illustrate the theory.