The robustness optimization of a multivariable feedback system in Hankel norm space

Abstract
This paper is concerned with the optimization of robustness in a multi-input multi-output linear time-invariant finite dimensional feedback system. The objective is to derive a closed-form solution to the problems of the synthesis of optimal controllers that either minimize the weighted sensitivity function or maximize the excess robust ness with respect to Hankel norm criterion. An all-pass solution for the minimum Hankel norm is employed to treat our problems. Finally, the infinite norm case is also discussed.