Mechanical Power Assist Equipment Using Springs for Lower Limb Rehabilitation

Abstract

In this paper, we describe a passive power assist system for the lower limb rehabilitation. The proposed system is composed of a mechanical gravity compensation system and a mechanical stiffness control system. By employing the clutch mechanisms, the proposed mechanical stiffness control system can present the desired stiffness around the tip of the system for arbitral postures. On the other hand, the gravity compensation system in the proposed system can produce the large gravity compensation force by amplifying the restoring force of the spring by a gear with high gear ratio. The system is safer than the previous ones because the total system is embedded within the link bodies. Thus, it will be preferable for wearable rehabilitation systems. The good performance of the proposed system as a gravity compensation system and a linear stiffness presentation system were verified through some experiments.