An approach to discrete-time sliding mode control with variable convergence rate to sliding surface

In this paper, we propose a new design method of the convergence rate in discrete-time sliding mode control. The design of a sliding surface is implemented by Ackermannpsilas formula in discrete-time domain. The discrete-time sliding mode control based on Luenburger observer is used for the controller. To improve performance limited by a fixed convergent rate, in this paper, we use variable convergence rate. The variable convergence rate is a nonlinear function with saturation. Numerical simulations are performed to illustrate its improved performance.