A Novel Multi-Axis Compliant Prosthetic Ankle Foot to Support the Rehabilitation of Amputees

Passive compliant prosthetic ankles have the advantage of energy saving, light weight, simple structure and competitive cost compared to powered devices. Despite of the variety of commercial products, these designs do not provide adequate degree-of-freedom during amputees' movement. It hampers them from walking comfortably especially on undulating and rough terrains. This paper presents a novel design of a multiaxis fully compliant prosthetic ankle. Finite element analyses are carried out to evaluate the mechanical behaviors of the design obtained by an optimization procedure. The designed prosthesis not only has a capability of bending and compression to store elastic energy and release it to assist in forward propulsion of the body but can also facilitate eversion motion when persons with disability move on rough road by integrating a circular flexure hinge. These characteristics make it more versatile and reduce the impact force on residual limbs.