Design and Simulation of a Passive Transfemoral Prosthesis with Bi-functional Muscles Characterisitcs

There are few work on the passive transfemoral prosthetic (PTP) mechanism because it failed to find an available configuration to drive the knee in a human-like gait motion steadily. In this paper, the kinesiology of the human lower limb is studied, a PTP mechanism is proposed, and it can perform human-like gait characteristics of the knee and ankle followed by the hip movement. Besides, a bifunctional bionic muscle is designed for the prosthetic knee, which can mimic the work performance of gastrocnemius and tibialis anterior, and it can provide impedance for the knee and ankle to keep the lower limb not collapse at the heel-off phase and assist the lower limb in lifting from the ground easily at the end of stance phase. Finally, the simulation-based kinematic and dynamic verification is carried out for the proposed transfemoral prosthesis. The results show that the prosthesis has human-like movement capacity of knee and ankle, and the dynamical performance of bifunctional bionic muscle is also verified.