Model Following Quasi-Sliding Mode Control Strategy

Abstract

Our study introduces a new model reference based approach to the design of sliding mode controller for discrete-time dynamical systems subject to external disturbances. We propose to begin the control design with generation of the reference trajectory for the system using its mathematical model and a hyperbolic tangent based sliding mode reaching law. Next, for the real disturbed plant, we propose a reaching function, which follows the reference trajectory in each step. Further, we prove that this approach ensures existence of quasi-sliding motion according to the definition of Gao et al. Moreover, the proposed controller offers a significant reduction of the width of the achieved quasi-sliding mode band in comparison to other sliding mode methodologies, which results in an improvement of the system’s robustness. The properties of our control scheme are finally illustrated with a simulation example.