Fixed poles of simultaneous disturbance rejection and decoupling: a geometric approach

Abstract

When the simultaneous disturbance rejection and regular block decoupling problem by static state feedback is solvable, and under some unrestrictive minimality assumption, all the poles of the closed-loop system can be placed, except the so-called fixed poles (which are present for any solution). We present here a geometric characterization for this set of fixed poles as well as a constructive procedure (based on geometric tools) for designing a feedback solution of the problem which assigns the remaining poles to arbitrary prespecified locations.