Knee Trajectory Modulation for Impact Reducing of Lower Limb Exoskeletons

Abstract

lower limb exoskeletons have gained considerable interest in the past several years thanks to its effectiveness in rehabilitation and walking assistance. During walking, repetitive and excessive foot-ground impact force makes the patient uncomfortable and even leads to secondary damage. In this paper, we proposed a humanoid method to reduce the Peak of Ground Reaction Force (PGRF) by Knee Trajectory Modulation (KTM). The main idea is to imitate the humanoid passive motion of the compliant leg by modulating the active knee trajectory of the exoskeleton. Different from traditional shock absorption methods by passive mechanical devices, the proposed method enables adjustment of leg stiffness and without bulky mechanical structures. We demonstrated the effectiveness of the proposed KTM in the AIDER lower limb exoskeleton system. Experimental results indicate that the proposed KTM can effectively reduce the PGRF.