Saturated Switching Functions for Sliding Mode Control With Speed Error Limitation

The saturated non-singular terminal switching function (SNTSF) for sliding mode control with speed error limitation and finite-time error convergence is proposed. The sliding-mode dynamics and the boundary layer dynamics of the SNTSF are analyzed. It is also shown that the non-singular terminal switching function does not have a higher boundary layer position tracking precision than the linear switching function, contrary to some previous claims in the literature. An SNTSF sliding mode controller with speed error limitation and finite-time convergence is proposed and tested both simulatively and experimentally on a laboratory DC motor system.