Optimal Discrete-time Sliding Mode Control for Nonlinear Systems

This paper presents an optimal discrete-time sliding mode control for simple-input simple-output nonlinear systems subject to input constraints. The proposed controller is developed on the basis of quasi-sliding mode concept. It ensures the finite-time convergence, the stability of the closed-loop system, as well as the follow-up of reference model. Chattering phenomenon is eliminated using the saturation function as a smooth switching function in the controller design. Moreover, particle swarm optimization algorithm is used in the design of the sliding surface in order to optimize the system response characteristics in presence of control input constraints. The effectiveness of the developed scheme is illustrated with an inverted pendulum system.