Time-based transmission power policies for energy-efficient wireless control of nonlinear systems

We present a controller and transmission policy design procedure for nonlinear wireless networked control systems. Our objective is to ensure the stability of the closed-loop system, in a stochastic sense, together with given control performance, while minimizing the average power used to generate the communication instants. The controller is designed by emulation, i.e. ignoring the network, and the transmission instants are generated by a so-called time-based threshold policy. The latter consists in waiting a given amount of time since the last successful transmission instant before using a constant power to transmit. We explain how to select the waiting time and the power to minimize the induced average communication power while ensuring the desired control objectives.