Digital Redesign of Sliding Mode Control Algorithms Using Saturation Function: State and Multirate Output Feedback Approach

Though continuous-time sliding mode control has a variety of desirable properties, its discrete-time counterpart does not guarantee the same performance. This is due to the fact that most of the discrete-time sliding mode control algorithms are based on reaching laws that are only approximations of continuous-time reaching laws and thus may not give a performance close to continuous-time sliding mode control. This paper presents a method for digital redesign of sliding mode control using saturation function based on state feedback. The method is extended to multirate output feedback case. It is shown that performance of the proposed controller is close to the performance of a pre-designed continuous-time sliding mode control algorithm. The method is illustrated by a numerical example