A BEHAVIORAL-APPROACH TO THE H-INFINITY OPTIMAL-CONTROL PROBLEM

This paper considers the general H-infinity optimal control problem fr om a behavioral perspective. A formalization of this problem is given that departs from the usual H-infinity control paradigm in the sense t hat system variables of the plant are treated in a symmetric way, with out distinguishing control inputs, measurements, exogenous inputs and to-be-controlled variables. Interconnection variables are introduced a nd controllers are allowed to constrain the interconnection variables of the plant. Necessary and sufficient conditions are given for the ex istence of controllers that achieve an H, control objective for a give n linear time-invariant plant. The set of all such controllers is para metrized by means of J-spectral factorizations. (C) 1997 Elsevier Scie nce B.V.