Sliding-Mode Control for Sampled-Data Systems Over Fading Channels: Dealing With Randomly Switching Sampling Periods
Zhiru Cao, Zidong Wang, Jun Song, Yugang Niu
Abstract
This paper investigates the sampled-data sliding mode control (SMC) problem for a class of uncertain systems with matched disturbances, where the sampling period switches among several different values in a random way and the system state is transmitted to the controller via a fading wireless channel. By applying the coordinate transformation and the input delay techniques, the underlying system with randomly switching sampling period is converted into a certain reduced-order system involving multiple probabilistic delays falling into several intervals. With the aid of an extended Lyapunov-like functional, a sufficient condition is established to ensure the mean-square exponential ultimate boundedness of the resultant closed-loop system and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\tilde{\varpi }$</tex-math></inline-formula> -reachability of the specified sliding surface. Furthermore, an optimization problem is formulated with the objective of simultaneously achieving fast convergence of the state trajectory, small ultimate bound of the system state and small sliding bound, and a genetic algorithm is utilized to solve such an optimization problem. Finally, the proposed sampled-data SMC scheme over the fading channel is illustrated through the simulation studies on the tracking problem for a mobile robot.