Comparision of different control algorithms for a knee exoskeleton

Abstract

Though the rapidly development in exoskeleton robot area, there are still some challenges, such as the safe and friendly human-machine interaction. In this paper, we proposed a novel knee exoskeleton driven by Series Elastic Actuator (SEA) which is a compliant actuator has the characteristic low output impedance, low friction, high quality force control and back-drivability. As for walking assistance, the force control is vital. Here, we mainly apply two control method to achieve the robust force control, one is the feedback control with enchaned distrubance observer, another is the Integral Sliding Mode Control (ISM). We test both the stability and force tracking performance of the two controler. The result showed that both algorithms can achieve the satisfactory performance and the ISM algorithm obtained the slightly better result.