H∞ OUTPUT FEEDBACK CONTROL FOR UNCERTAIN NEUTRAL TIME-DELAY SYSTEMS:AUGMENTED DYNAMICS AND AUGMENTED LYAPUNOV FUNCTIONAL APPROACHES

In this paper the robust H∞ output feedback control of uncertain neutral time-delay systems with norm-bounded type uncertainties is investigated. The control input is utilized as the augmenting state term and the system is represented in augmented dynamics form which enables to handle the design of the H∞ output feedback controller in terms of convex linear matrix inequalities (LMI) form which can be solved via interior-point algorithms. A novel augmented Lyapunov-Krasovskii functional is selected to obtain sufficient LMI conditions for the existence of delay-dependent H∞ output feedback control. Any model transformation and bounding for cross terms are strictly avoided to overcome the conservativeness of the results. A delay-dependent bounded real lemma is also presented in LMI form. Finally, several numerical examples are given to illustrate the effectiveness of the proposed method.