Passivity-based sliding mode controller/observer for second-order nonlinear systems

摘要

A passivity-based sliding mode control for a class of second-order nonlinear systems with matched disturbances is proposed in this paper. Firstly, a nonlinear sliding surface is designed using feedback passification, in which the passivity is employed to guarantee the closed-loop system's stability. The passivity-based controller comprising a discontinuous term guarantees globally asymptotical convergence to the sliding surface. A sliding mode-based control law that satisfies the reaching and sliding condition is also developed. Moreover, the passivity-based sliding mode observer is also developed to effectively estimate the system states. Compared with conventional sliding mode control, the proposed control scheme has a shorter reaching time; and hence, the system performance is less affected by disturbances, thus eliminating the need to increase the control input gain. Finally, simulation results demonstrate the validity of the proposed method.