SMC for Systems With Matched and Mismatched Uncertainties and Disturbances Based on NDOB

Abstract

This paper proposes a novel sliding mode control (SMC) approach for general nth order systems with matched and mismatched uncertainties and disturbances based on nonlinear disturbance observer (NDOB). By designing a novel sliding mode manifold integrated with a disturbance estimation technique, a NDOB-based SMC method is designed for these systems. As compared with the nominal SMC method, the proposed method obtains a better disturbance rejection ability in the presence of matched and mismatched uncertainties and disturbances, it can ensure a satisfactory system performance and reduce the chattering in case of reducing the switching gain. A rigorous stability analysis of the composite closed-loop system is provided using Lyapunov theory and input-to-state stable concept. Finally, two simulation results are provided to verify the effectiveness of the proposed control method.