Design, Control and Implementation of a Powered Prosthetic Leg

Abstract

The design, control and implementation of a lower limb prosthesis with powered knee and ankle for transfemoral amputees are described in this paper. Firstly, the mechanical design is introduced. Then a hierarchical control approach for walking coordination is proposed. The hierarchical control approach acquires expected motion trajectory of prosthesis which is obtained from the movement physiological information of the amputee’s healthy leg collected by Inertial Measurement Unit (IMU). Meanwhile, the motion recognition during walking is carried out by decoding of EMG signals. In order to verify the design and its ability to assist walking, an impedance controller was used on the prototype of the powered lower limb prosthesis and a transfemoral amputee subject was invited to participate in the wear experiment. The experimental data shows that the designed mechanical structure and the proposed control method can make the prosthesis produce similar movement characteristics of the amputee’s healthy leg. It allows transfemoral amputees to have gaits close to those of normal people.