Development of Prosthetic Finger including an Actuator

Abstract

A new prosthetic finger including an actuator in the proximal phalanx has been developed for finger amputees. By designing the prosthetic finger with the actuator inside, the mounting part does not need to include the actuators; this leads to a simple and compact design of the prosthetic finger. Thus, the comfort of wearing and the aesthetics for the user are improved. The proposed prosthetic finger is designed as under-actuated mechanism having four degree-of-freedoms (4-DOFs) with the distal interphalangeal joint (DIP joint) driven directly (1-DOF) and the proximal interphalangeal joint (PIP joint) and the metacarpophalangeal joint (MCP joint) driven indirectly (3- DOFs). The indirect driving is realized using leaf springs. The force from the actuator is transferred to each phalanx by the tendon. The finger enables self-adaptive grasping according to object shapes as well as flexion/extension motions and adduction/ abduction motions. The prototype was manufactured using 3D printing and machining. Experiments show the feasibility of the proposed prosthetic finger.