A Customized One-Degree-of-Freedom Linkage Based Leg Exoskeleton for Continuous Passive Motion Rehabilitation

Leg exoskeletons have gained popularity in clinical settings for gait training in the past decades. However, current devices are restricted in clinical setting due to their complexity and bulkiness. On the contrary, 1-DOF linkage based finger exoskeletons for continuous passive motion (CPM) rehabilitation can be compact and portable. Such concepts have not been exploited in leg exoskeletons. In this paper we attempt to develop a leg exoskeleton based on a 1-DOF linkage for CPM rehabilitation. First dimensional synthesis returns optimal dimensions for a 1-DOF-8-bar-10-joint linkage. Then dynamic simulation estimates the input torque for actuation design. An open-loop control system is also developed. In the end, we achieved a leg exoskeleton that can generate a human-like gait pattern at hip and knee joints. The device can deliver CPM based rehabilitation. Due to its compactness and portability, it may be used outside clinical settings.