Co‐design of stabilisation and transmission scheduling for wireless control systems

Abstract

Wireless control system (WCS) refers to the feedback control system with state and (or) control information transmitted over wireless channels. The control system stability is severely affected by the wireless transmission reliability, which in turn relies heavily on the scheduling of limited wireless communication resources, such as channel, time and power. Therefore, co-design of control stabilisation and transmission scheduling is of vital importance. In this study, the authors firstly explore the effect of wireless transmission reliability on control performance for a WCS with multiple subsystems, local sensors and a remote combination of controller-scheduler. Then a feedback control method is designed to mitigate the impact of unreliable transmission in the loop of sensor-to-controller and controller-to-actuator. Stabilisation and transmission scheduling are co-designed to stabilise the system and minimise the control-communication cost by solving a mixed-integer non-linear programming problem. A decomposition scheme is finally proposed to optimise the control performance by minimising the gap with standard linear quadratic regulator controller as well as the communication cost by allocating the transmission channels, time-slots and power. The effectiveness and advantage of the proposed scheme are demonstrated by the simulation results for a slab temperature control system in hot rolling process.