Chattering-Free Adaptive Second-Order Terminal Sliding-Mode Controller for Uncertain System

摘要

In this paper, an adaptive second-order terminal sliding-mode (SOTSM) controller is proposed for controlling uncertain systems. The design procedure is carried out in two parts. A linear sliding surface is designed first, and then, using the linear sliding surface, the terminal sliding manifold is obtained. Instead of the normal control input, its time derivative is used by the proposed control law. The actual control is obtained by integrating the derivative control input. The discontinuous sign function is contained in the derivative of the control input, and hence, chattering is eliminated in the actual control. An adaptive tuning method is designed to deal with the unknown system uncertainties, and their upper bounds are not required to be known apriori. System stability is proved by using the Lyapunov criterion. Simulation results demonstrate the effectiveness of the proposed controller for both the single-input single-output (SISO) and multi-input multi-output (MIMO) uncertain systems.