Robust decentralised state feedback control design for large-scale networked control system

This paper deals with H-infinity robust decentralised feedback control for large-scale networked control systems (NCSs). A NCS model is extended to a class of large-scale system. Less conservative sufficient conditions are formulated in the form of a nonconvex matrix inequality, of which a feasible solution can be obtained by solving an optimisation problem in terms of linear matrix inequalities. The sufficient conditions are constructed by a set of new Lyapunov-Krasovskii functionals, which are based mainly on the lower and upper bounds of delay and packet loss. An explicit expression for the desired robust decentralised state feedback control law is also given. In order to verify the proposed method, it is applied to a numerical example and the load frequency problem in a multi-area power system. The simulation results show good performance and more robust stability against digital network communications delays, packet loss and external disturbances.