Design of a cost-effective EMG driven bionic leg

Conventional low cost leg prosthesis, available in Third World countries, is essentially a fixed passive structure which makes walking possible with some difficulty, and climbing stairs with such is extremely difficult. The present work was taken to design prosthesis for above-knee amputees. The low cost bionic leg prosthesis, which has an active (battery powered) limited rotational movement of the knee joint, is controlled by voluntary EMG (electromyogram) signals from two opposing muscles from the thigh; one to rotate the leg backward (flexion) and the other forward (extension). The design involved developing the necessary EMG and processing circuitry, interfacing the output to the microcontroller, developing the driving circuitry for bidirectional rotation of the motor, and programming the microcontroller. During the course of the present work it was possible to control the rotation of a motor using a simulated EMG signal. The completed designed prosthesis will allow a user not only to walk with a better gait, but also to climb stairs with ease.