Reaching law based DSMC with a reference model

Abstract

Discrete time sliding mode control (DSMC) strategies are well known to ensure good robustness of the system with respect to perturbations. However, since such algorithms specify dynamics of the plant on a step-by-step basis, their performance is deteriorated by the residual effect of past disturbance on the system state. To counteract this effect, in our paper we propose a new approach using a reference model of the plant. In this approach, a discrete time reaching law is first used to specify dynamics of the disturbance-free model. Then, a secondary control signal is obtained with the aim of driving the state of the actual plant alongside the desired trajectory provided by its model. As a result, only the single most recent disturbance term has an effect of the system state, which effectively enhances its sliding mode performance.