H/sub /spl infin// control for uncertain neutral systems via non-fragile state feedback controllers

This paper deals with the problem of non-fragile H/sub /spl infin// control for neutral systems with time-varying delays. The state feedback gains to be designed are subject to norm-bounded uncertainties. The purpose of the problem is the design of a state feedback controller such that the resulting closed-loop system is asymptotically stable while satisfying a prescribed H/sub /spl infin// performance level for all admissible uncertainties in the controller gain. Sufficient conditions for the solvability of this problem are obtained for the cases with additive and multiplicative controller uncertainties, respectively. A desired non-fragile state feedback controller can be obtained by solving certain linear matrix inequalities.

1 Introduction

Time delay is frequently a Source of instability and poor performance in a control system. Time delays can be encountered in various engineering systems such as chemical processes and long transmission lines in pneumatic systems [2]. Therefore, control of delay systems has received considerable attention an. has been one of the’ most interesting research topics in the past years. Usually, there are many types of delay systems; among them, delay systems with neutral type have been studied since many engineering systems can be modeled by using functional differential equations of the neutral type. Practical examples of neutral delay-differential systems can be found in the distributed networks containing loss-less transmission lines [lb population ecology [4], and other areas [5]. The problems of stability analysis and control of neutral systems have been investigated and many results on these topics have been obtained [5].