H-INFINITY CONTROL AND QUADRATIC STABILIZATION OF SYSTEMS WITH PARAMETER UNCERTAINTY VIA OUTPUT-FEEDBACK

This note focuses on linear systems which are subject to both time-varying norm-bounded parameter uncertainty and exogenous disturbance, and addresses the following robust H(infinity) control problem: designing a linear dynamic output feedback controller such that the closed-loop system is quadratically stable and achieves a prescribed level of disturbance attenuation for all admissible parameter uncertainties. It is shown that such a problem is equivalent to a scaled H(infinity) control problem.