Design of a 3D-printable, robust anthropomorphic robot hand including intermetacarpal joints

This paper presents a new mechanical design of an anthropomorphic robot hand. The hand is designed such that it is adaptive, backdrivable, modularized to provide both dexterity and robustness. The hand has 18 joints, 14 degrees of freedom, and a new joint mechanism called an active DIP–PIP joint for the robot finger. The mechanism includes a pair of movable pulleys and springs for generating both linked and adjustable motions. Although the set of DIP (distal interphalangeal) and PIP (proximal interphalangeal) joints exhibits a coupled movement in free space, it moves adaptively when it contacts an object. To ensure a 1:1 ratio movement when a finger is moving freely and to produce additional joint torque when gripping an object, torsion springs are attached to each joint. The backdrivability of each joint is realized using an actuation module with a miniature BLDC motor and a ball screw. In addition, the relatively unknown intermetacarpal joints, which provide additional dexterity to the hand for grasping small objects, are used in the robot hand model. A modularized design simplifies the assembly of the hand and increases the economic feasibility. Experimental results are included in this paper for validating the design of the robot hand.