Experimental Study on an Active Knee Joint Mechanism without an External Energy Source

An above knee prosthesis that is used by femoral amputees has a knee joint mechanism as an alternative function of a knee. A Knee brace also has a knee joint mechanism for securing stability of a knee during the stance phase. Performance of the prosthetic knee joint highly affects activity and a cure of the patient. However, the practical knee joint mechanism that can generate active joint torque has almost never appeared, because of the problems of overweight, mechanical noise and energy consumption. In this study, a new joint mechanism that would be able to generate extensional knee joint torque by utilizing ground reaction force without an external energy source was examined. The torque generator composed of hydraulic cylinders was designed by considering the results of gait analysis. The experimental trial model of a knee brace was made for a normal subject. Effect of the torque generator was experimentally examined by electromyogram of vastus medialis and by measuring generative torque during extension of a knee joint