Optimized design of a body-powered finger prosthesis using fingertip trajectories based on polar coordinate analysis

This paper presents a design and evaluation of a customized finger prosthesis that generates a natural finger motion. The design of the prosthesis followed two primary requirements: i) The size of the prosthesis should reflect that of an amputee’s finger; ii) the prosthesis should enable the natural finger motion of the amputee. To achieve these aims, two methods were employed: i) An incomplete fourbar mechanism by utilizing the remaining joint of a subject as the joint in the mechanism; ii) a fingertip trajectory analysis in polar coordinates to model the natural finger motion. In this paper, we focused on the design of the finger prosthesis so that the prototype was manufactured based on the finger information of a normal subject before applying it to the actual finger amputee. The performance of the proposed system was verified by intensive experiments for grasping and manipulation with the proposed system.