Knee and Ankle Powered Above-Knee Prosthesis Design and Development

Amputation has vast influence on life of amputees. Despite technology advancements, above-knee leg amputees still have quite a problem ascending stairs. At Faculty of Mechanical Engineering and Computing, University of Mostar, we are developing above-knee prosthesis that would be able to perform stair ascent in natural manner. The goal is to mimic main leg muscles by using actuators. First tests of the prosthesis showed that it is not enough to power prosthesis using only knee actuator and that in order to achieve more natural stair ascent ankle actuator should be integrated into a prosthesis design. This paper presents our current design of the above-knee prosthesis and its functions. The prosthesis is powered in the knee and in the ankle by hydraulic actuators. With the ankle actuator integrated into the design, prosthesis showed much better results, closer to the natural stair ascent. Current prototype of the prosthesis was designed by using combination of custom-made and off-the-shelf components which proved to be good for initial tests and experimental purposes. However, novel components need to be developed in order to optimize the prosthesis and make its design less rough, more ergonomic and user friendly.