Design of backdrivable soft robotic finger mechanism

This paper presents a new joint actuation mechanism, called Active DIP-PIP (ADP) joint, for robotic finger. The mechanism consists of a pair of moveable pulleys and springs to generate both linked and adjustable motion. While the set of DIP (Distal-Interphalangeal) and PIP (Proximal-Interphalangeal) joint shows coupled movement in free space, it moves adaptively when it contacts with an object. The torsion springs attached on each joints ensure 1:1 ratio movement while finger is moving freely and produce additional joint torque while grasping an object. In addition, actuation module composed of miniature BLDC motor and ball screw allows each joint to be back drivable.