Robust Position Control of Series Elastic Actuator with Backstepping Based on Disturbance Observer

Abstract

Series Elastic Actuator (SEA) is a powerful device in the area of human-robot collaboration. However, it still suffers from difficult position control issues. Therefore, an efficient approach is proposed to solve this problem in this paper, in which a disturbance observer (DOB) and a nonlinear robust controller are synthesized via backstepping method. The disturbance observer is designed to estimate parameters uncertainty and unmodeled dynamics, while the nonlinear robust controller stabilizes closed loop system. The boundedness analysis is presented and global convergence is analytically proven. Experiment results illustrate the effectiveness of the proposed scheme.