On A Discrete-Time Quasi-Sliding Mode Control

This paper proposes a discrete-time sliding mode control approach for applications in discrete-time systems. The reaching phase and quasi-sliding mode are investigated in details, based on which the discrete-time sliding mode control strategies are developed. With the proposed method, the system states move towards the quasi-sliding mode band in finite steps and stay within that band thereafter. The quasi-sliding mode band is designed to be variant, which can increase the reaching speed of the system to the quasi-sliding mode band. The implementation of quasi-sliding motion of the system is proved theoretically. The proposed discrete-time sliding mode control can guarantee the robustness to both the internal parameter variations and the external disturbances. At the same time the controlled systems could achieve faster error convergence and higher steady-state accuracy. The simulation results show the effectiveness of the proposed method.