A wired actuated elbow for human prosthesis

The mechatronic solutions used in robotic field are more and more used in other areas. Conspicuous research teams are working on arm prosthesis, investigating and developing new mechanical architecture and actuator. The mean aspect is to set up mechanical devices, actuators and energy supply. This paper presents a new mechanical elbow to install on artificial arm for human prosthesis. The device is based on 3 hydraulic actuators connected through some wires to the following forearm components. A complex and optimized path of wires makes actuators work with almost constant linearity between extensions of pistons and flexion-extension and pronation-supination angles. A kinematic 3D virtual model is presented at a second step of geometrical optimization. The authors decided to use redundant actuators, 3 instead of 2, to modulate the mechanical compliance of the artificial arm depending on the kind of operation the patient will wish perform. Moreover, in parallel, the authors are working with the third piston that collaborates with the others to optimize the volume and minimize the stresses.