ROBUST TRACKING AND DISTURBANCE REJECTION FOR DECENTRALIZED TIME-DELAY SYSTEMS

The decentralized robust servomechanism problem, which is to design decentralized stabilizing controllers such that each decentralized output robustly tracks a given reference signal in the presence of certain disturbances, is considered for linear time-invariant time-delay systems of retarded type with discrete delays. The reference signals and the disturbances are assumed to satisfy a constant-coefficient linear delay-differential equation of retarded type with discrete delays. Necessary and sufficient conditions for the solvability of this problem are presented. The structure of the controller which solves this problem is also given.