An EMG-based finite state approach for a microcomputer-controlled above-knee prosthesis

A novel self-contained microcomputer-controlled above-knee prosthesis (AKP) has been developed. The knee mechanism is equipped with a magnetic particle brake providing a continuously variable resistive moment. Several sensors measure the contact pressure under the prosthetic foot, the knee angle and EMG-signals from the stump muscles. This information enables the microcomputer to adjust the braking moment automatically depending on gait mode, gait velocity and other locomotion requirements. The control action is based on a finite state representation of the gait cyclus.