On the use of reduced-order models in output feedback design of discrete systems

The problem of designing output feedback controllers for discrete systems using reduced-order models is investigated in this paper. It is shown that neglecting nondominant modes does not generally guarantee the stability of the closed-loop system. Certain special structures have been identified for which the use of static and dynamic feedback controllers can provide a stabilizing effect. Examples are presented to illustrate these structures. © 1985.