Combined modal and singular perturbation approach to decentralized control

A method is presented for the systematic design of decentralized controllers for large-scale interconnected dynamical systems. The design method employs modal and singular perturbation techniques to affect decoupling of the interconnection into its subsystem components. Once the decoupling is achieved, local controllers for each subsystem are designed individually to place the closed-loop poles of each subsystem in some prespecified locations in the complex plane. The resulting controllers are then used to generate local control inputs, using local information only. A dynamical system comprising four interconnected subsystems is taken as example. Simulation results show that the decentralized controller obtained by the proposed method is comparable to that obtained by conventional global controller design methods.