H(2) design of one-degree-of-freedom decoupling controllers for square plants

Abstract

Decoupling design of one-degree-of-freedom controllers is treated for the generalised plant model within the H(2) framework. The class of all realisable closed loop transfer matrices is parametrised under a mild assumption on non-unity feedback sensors. A set of compact assumptions is presented to guarantee the existence of the optimal H(2) controller. Together with the optimal one, the class of all H(2) controllers that yield finite H(2) cost is obtained. The optimal closed transfer matrix and its associated controller are shown to be strictly proper under the reasonable order assumptions on the generalised plant.