Performance Assessment for Unstable and Nonminimum-Phase Systems

Abstract

This article derives extensions of minimum variance control evaluation techniques to general systems, including unstable and nonminimum-phase plants. An analysis of the sensitivity of these methods to uncertainties in the location of unstable poles and non-invertible zeros is presented. Through two simple examples, it is shown that grave errors may be encountered. when information on the unstable poles and non-invertible zeros of a system is not properly included in the performance evaluation techniques.