Class of stabilising decentralised controllers for interconnected dynamical systems

A method is presented for the systematic design of stabilising decentralised controllers for large-scale interconnected dynamical systems. The design method is based on (i) decentralised implementation of global controllers obtained by using existing global controller design methods, (ii) model reduction of dynamical systems, and (iii) modelling of the interactions among the subsystems comprising the global closed-loop control system. This is used for generating local corrective control signals, which would account for these interactions. The resulting decentralised controller uses local information only to generate local control inputs. It comprises local state feedback controllers and feedforward compensators. Three distinct schemes for the implementation of the controller are proposed. They all guarantee near optimal performance. A four-station interconnected dynamical system is considered. Results of time simulation studies demonstrate that the overall performance of the system under the proposed decentralised controller is near that of the global optimal controller.