ROBUST DISTURBANCE ATTENUATION OF A CLASS OF NONLINEAR SINGULARLY PERTURBED SYSTEMS

The problem of disturbance attenuation with internal stability for a class of nonlinear singularly perturbed systems is considered. Using H∞ approach, a state feedback controller is designed for the reduced order system such that L2 gain of this system to the relative disturbance input is made less than or equal to a prescribed value. In this paper, we propose a new theorem to show that the maximum difference between the performance index of the closed-loop singularly perturbed system with the designed slow controller, and the one related to the closed-loop reduced system, will be of order of ε. The results have been verified both analytically and through simulations.