ON THE ROBUST CONTROL VIA REFLECTION COEFFICIENTS

摘要

A robust version of the modal controller design for discrete-time systems is introduced. Instead of a single stable point a stable simplex must be preselected in the closed loop characteristic polynomials coefficients space. A constructiveprocedure for generating simplexis inside the "nice stability region" is given starting from the unit hypercube of reflection coefficients of monic polynomials. This procedure is quite straightforward because, first, n edges are generated by a linearSchur invariant transformation and, second, the most critical edge is determined by the difference of reflection coefficients numbers. The procedure of robust controller design makes use of a stability measure defined as the minimal distance between apreselected stable simplex and vertices of an uncertain polytopic plant.