Nonlinear Disturbance Observer based Sliding Mode Control for a Class of Uncertain Nonaffine Nonlinear Systems

Abstract

Abstract. In this paper, the sliding mode tracking control is proposed for a class of uncertain non-affine nonlinear systems via the nonlinear disturbance observer(NDOB). Based on the Taylor expansion method, the affine system is approximated to facilitate the desired control design. Then, the NDOB is adopted to estimate the unknown disturbance. Subsequently, based on approximated affine nonlinear model and the NDOB, the sliding mode tracking control is proposed for non-affine nonlinear systems with uncertainty. The control scheme can guarantee semi-global uniform boundedness of the closed-loop system signals as proved by Lyapunov analysis. Numerical simulation results are presented to illustrate the effectiveness of the proposed sliding mode tracking control scheme.