| description abstract | Providing powered joint actuation is a major focus of research in the lowerlimb prosthesis area. The capability of actively powering the joints enables the prosthesis to meet the energetic requirements of locomotion, and thus provide higher performance in restoring the lost lowerlimb functions in comparison with traditional passive prostheses. In this paper, a powered transfemoral (aboveknee) prosthesis is presented, in which the knee and ankle are powered with pneumatic muscle actuators. A new variableradius pulleybased mechanism is utilized, which enables the free adjustment of actuation torque curve to better match the desired torque curve as dictated by the locomotive requirements. Additionally, a springreturn mechanism is also incorporated, which replaces the muscle actuator in the “weak†(less torquedemanding) direction with a set of mechanical springs. With this mechanism, both knee and ankle joints can be powered while maintaining a compact profile of the prosthesis. The design details are presented, and the prosthesis is able to provide sufficient torque for an 85 kg user in various locomotion modes. A prototype of the prosthesis has been fabricated and tested, with the preliminary results indicating that this prosthesis is able to provide a walking gait similar to that of a healthy person. | |
