A two-fingered anthropomorphic robotic hand with contact-aided cross four-bar mechanisms as finger joints

Abstract

This paper presents an anthropomorphic design of a robotic finger with contact-aided cross four-bar (CFB) linkages. Anatomical study shows that finger joints have a complex structure formed by non-symmetric surfaces and usually produce complex movement than a simple revolute motion. The articular system of human hand is firstly investigated. Kinematics of a CFB mechanism is then analyzed and computer aided design of fixed and moving centrodes of CFB mechanism is presented. Gripping analysis of human hand shows two easily ignored components of a finger, fingernail and soft fingertip. Based on the range of motion of the joints of the most flexible thumb finger, a two-joint anthropomorphic finger is developed by using contact-aided CFB linkages which can also be used for joint design of prosthetic knee. Prototype of a two-fingered hand is manufactured by using 3D printing technology and gripping of a wide range of objects is tested.