Ripple Minimization for Harmonic-geared Series Elastic Actuator under Force Control

Abstract

This paper develops an accurate force control algorithm an reduce the effect of torque ripple for the Series Elastic Actuators (SEA). The harmonic drive is a geared system which is widely utilized in actuators such as SEA. However, it becomes a big challenge to achieve highly accurate force control performance in SEA because of harmonic drive torque ripple. In this study, the harmonic drive ripple model is analyzed and characterized. The derived model is utilized to minimize the effect of ripple with force observation and controller for SEA. Experimental verifications are conducted to evaluate the performance of the proposed algorithm.