Design analysis of a passive weight-support lower-extremity-exoskeleton with compliant knee-joint

This paper presents the design concept of a weight-support lower-extremity-exoskeleton (LEE) with a compliant joint to relieve compressive load in the knee. Along with a leg dynamic model and a knee bio-joint model, a compliant exoskeleton knee-joint has been designed using topology optimization and experimentally evaluated. Results suggest that the gait-based design of a LEE can be divided into two parts in terms of knee angles; compliant coupling and body-weight support. The concept feasibility and dynamic models of the passive LEE design have been experimentally validated with measured plantar forces. Both simulation and experimental results agree with data in-vivo confirming the effectiveness of the LEE in supporting human body-weight during walking, and also provide a basis for computing the internal knee forces as a percentage of bodyweight.