Find in Library

When using the powered lower-limb prosthesis, it is important to obtain varying amputee's weight to prevent an excessive knee flexion in the early stance phase of finite state impedance control. This paper proposes a method for implementing an impedance controller that can operate independently of the varying load mass for reaction force sensing elastic actuator (RFSEA) with a linkage arm. The proposed controller estimates the load mass using recursive least square. We apply a Kalman filter and a disturbance observer to improve the accuracy of the measurement and the tracking performance of the force controller, respectively. The results of an experiment applying a lab-developed RFSEA system with a linkage arm validate the feasibility of this approach. It is also expected that the proposed system reduces the size and development costs of the prosthesis due to the advantages of using the RFSEA.