Kinematic Analysis of a Novel Couple-Adaptive Underactuated Finger Mechanism

Abstract

This paper presents the design of finger mechanism with one active DOF that combines underactuation mechanism and spring elements. The three phalanges of human finger can not only rotate simultaneously with a certain ratio before touching the grasped object, but can also envelop the object successively even if some of them are blocked, called the Couple-Adaptive feature. To realize this function in the finger mechanism, a novel underactuated four-bar mechanism is proposed in this paper. The kinematics model has been derived based on a vector analysis. The simulations of kinematic analysis show that this underactuated finger mechanism has anthropomorphic motion and grasping feature. And its workspace indicates that this prosthetic finger could complete most of grasping tasks.