Robust reliable control for a class of uncertain nonlinear state-delayed systems

This paper deals with the problem of robust reliable control design for a c lass of nonlinear uncertain state-delayed systems. The system under conside ration involves state time delay, parameter uncertainties and unknown nonli near disturbances. The nonlinearities are assumed to satisfy the boundednes s condition, and the parameter uncertainties are allowed to be time-varying unstructured. The purpose of this problem is to design the state feedback controller such that, for all admissible uncertainties as well as actuator failures occuring among a prespecified subset of actuators, the plant remai ns globally exponentially stable, independently of the time delay. An effec tive, modified algebraic Riccati equation approach is developed to solve th e problem addressed. It is shown that designed nonlinear time-delay control systems provide guaranteed robust reliable stability despite possible actu ator failures. We present an illustrative example to demonstrate the applic ability of the proposed design approach. (C) 1999 Elsevier Science Ltd. All rights reserved.