A new passive transfemoral prosthesis mechanism based on 3R36 knee and ESAR foot providing walking and squatting

Abstract

Researchers have proposed various linkage mechanisms to connect knee and ankle joints for above-knee prostheses, but most of them only offer natural walking. However, studies have shown that people assume a squatting posture during daily activities. This paper introduces a novel mechanism that connects the knee joint with the foot-ankle joint to enable both squatting and walking. The prosthetic knee used is the well-known 3R36, while the energy storing and return (ESAR) prosthetic foot is used for the ankle-foot joint. To coordinate knee and ankle joint movements, a six-bar linkage mechanism structure is proposed. Simulation results demonstrate that the proposed modular transfemoral prosthesis accurately mimics the motion patterns of a natural human leg during walking and squatting. For instance, the prosthesis allows a total knee flexion of more than 140° during squatting. The new prosthesis design also incorporates energy-storing mechanisms to reduce energy expenditure during walking for amputees.