Robust and non-fragile H∞ control of parameter uncertainties time-varying delay systems

This paper describes the synthesis of robust and non-fragile H∞ state feedback controllers for linear systems with time delay and parameter uncertainties, and static state feedback controller with multiplicative uncertainty. The sufficient condition of controller existence, the design method of robust and non-fragile H∞ state feedback controller, and the measure of non-fragility in controller are presented. Also, using some changes of variables and Schur complements, the obtained sufficient condition can be rewritten as an linear matrix inequality form in terms of transformed variables. Therefore, the obtained robust and non-fragile H∞ controller guarantees the asymptotic stability and disturbance attenuation of the closed loop system in spite of controller gain variations within a degree