OUTPUT STABILIZING ROBUST-CONTROL FOR DISCRETE UNCERTAIN SYSTEMS

A comprehensive solution to the problem of the robust output min-max c ontrol for discrete uncertain MIMO systems with matched uncertainties is presented in this paper. In the literature, state-dependent Lyapuno v and Riccati min-max controllers were treated independently and the e xistence problem of the output min-max controllers has not been fully resolved. In this paper, both Lyapunov- and Riccati-based min-max outp ut control laws are treated, and a simple criterion for the existence of a min-max output controller is provided It is shown that when the c riterion is satisfied, both Riccati- and Lyapunov-based output min-max controllers exist. The first controller is applied directly to the gi ven system, while the latter controller is applied to the given system closed with a suitable feedback. Moreover, it is shown that both over all controllers are identical. In addition, an alternative criterion f or the existence of a Lyapunov-based min-max output control, in terms of discrete positive real properties of the system, is derived. (C) 19 98 Elsevier Science Ltd. All rights reserved.