An LMI approach to output-feedback-guaranteed cost control for uncertain time-delay systems

This paper considers the problem of output-feedback-guaranteed cost control ler design for uncertain time-delay systems. The uncertainty in the system is assumed to be norm-bounded and time-varying. The time-delay is allowed t o enter the state and the measurement equations. A linear quadratic cost fu nction is considered as a performance measure for the closed-loop system. N ecessary and sufficient conditions are provided for the construction of a g uaranteed cost controller. These conditions are given in terms of the feasi bility of LMIs which depend on a positive definite matrix and a scaling var iable. A numerical algorithm is developed to search for a full order dynami c output-feedback controller which minimizes the cost bound. Copyright (C) 2000 John Wiley & Sons, Ltd.