Decentralized control of time-delayed uncertain symmetric composite systems

Reduced-order control design for a class of time–delayed uncertain nonlinear but nominally linear systems composed of identical nominal subsystems and symmetric interconnections is presented. Symmetric composite systems with time–delays and bounded parametric uncertainties both in subsystems and interconnections system matrices are considered for decentralized output control design using a controller–observer scheme. Luenberger–like delay–less observer is considered. First, an artificial reduced-order design model is constructed. Its dimension equals to the dimension of a subsystem in the original system. Stabilizing controller–observer is designed for this reduced-order design model using well known methods. It is shown that when this output controller is implemented into each subsystem of the original system then such decentralized output controller quadratically stabilizes the overall system.