Robust control of a class of nonlinear uncertain time-delay systems

Abstract

The robust ?? control problem of a class of uncertain nonlinear time-delay systems is considered in this paper. The parametric uncertainties are real time-varying and norm-bounded and the nonlinearities are state-dependent and cone-bounded. The delays are time-varying and bounded both in the state and at the input. We provide sufficient conditions for robust stability and robust state-feedback stabilization with disturbance attenuation. Then, we establish sufficient conditions for designing a linear dynamic observer-based controller which stabilizes the uncertain time-delay system and guarantees an ??-norm bound constraint on the disturbance attenuation for all admissible uncertainties and unknown delays. Several examples are simulated to illustrate the developed theory. � 2002 Taylor & Francis Ltd.