Discrete-time quasi-sliding mode tracking control of uncertain systems with long sampling interval

Abstract

This paper presents a discrete-time quasi-sliding mode controller of SIMO systems with parameter uncertainty and long sampling interval. The discrete quasi-sliding mode control system is designed to track the desired path on the basis of a Lyapunov function, and sufficient conditions of the switching gain are given to make the discrete system stable. Each component of the switching gain can be determined separately. The switching region is variable according to the product of the bounds of uncertainty and the amplitude of the trajectory. The controller is robust to the uncertainties, and the reaching condition of the control system is satisfied for any initial condition. This control law is a generalized form of the discrete quasi-sliding mode control and reduces the chattering problem considerably. Simulation results for motion control of an autonomous underwater vehicle which acquires position information with a discrete interval show the effectiveness of the proposed technique.