Nearly decoupled robust MIMO control of an unstable plant

Abstract

The design of a nearly decoupled, robust control system with an unstable plant is considered. The main aim is to present an effective design methodology that is applicable to a non-minimum phase and/or unstable multivariable uncertain plant. The controller resulting from the present design technique for nearly decoupled multivariable control has no right half-plane poles/zeros other than those specified by the designer, even when the given plant is of non-minimum phase and/or unstable. Unlike the prevailing techniques, the present approach can handle detailed and tight design requirements specified on the Bode array of the closed-loop system. Furthermore, a non-conservative robustness criterion presented in a previous paper is integrated into the design methodology such that the resultant design is robust in the presence of plant uncertainties.