Microcontroller use for the assistance of a prosthesis for above-knee amputees

Above-knee amputee gait analysis shows that a longer asymetry is related to the intrinsic prosthetic knee motion during the swing phase. A microcontroller-driven pneumatic knee mechanism can improve this phenomenon as well as increase confort and releive the patient strain during walking. The microcontroller, located in the leg, measures the duration of the stance phase and computes the optimum action of the pneumatic dumper in order to limit the knee flexion during the swing phase. It then gives an active initiation of knee extension and then provides a resistant action to knee extension which minimises the impact when the knee gets in contact with the extension bumper. The use of a microcomputer connected to an electrovalve allows to modulate the force of the pneumatic actuator when the walking speed varies, this resulting in a more physiological motion.