On the Optimal Multirate Control of Networked Control Systems

Optimal multirate control of the networked control systems is investigated in this paper. Under p – to – wσ communication sequence that sensors access communication medium and m – to – wρ communication sequence that actuators access communication medium, the plant of networked control system acts as a linear periodic time-varying system. Using lifting technology, a linear periodic time-varying system is transformed into a linear periodic time-invariant system and the linear quadratic performance index of a linear periodic time-varying system is transformed into that of a linear periodic time-invariant system. Controllability and observability of transformed system are analyzed. An optimal state feedback control and an optimal output feedback control are given. The simulation results show that the optimal multirate control strategies proposed in this paper are feasible. Key-Words: optimal multirate control; networked control systems; lifting technology; linear quadratic performance index; optimal state feedback control; optimal output feedback control