Sliding Mode Control for Wearable Exoskeleton based on Disturbance Observer

Abstract

In this paper, a sliding mode control method based on nonlinear disturbance observer is developed for the wearable exoskeleton. Firstly, in order to guarantee the tracking performance, an extended seconded order disturbance observer is designed to estimate the unknown disturbance. Then, an exponential approach sliding mode control law is designed based on the estimated value of the disturbance observer, and the Lyapunov theory is applied to analysis the closed-loop stability. Finally, simulation results testify the effectiveness of the proposed method for the wearable exoskeleton in the presence of unknown disturbance.