Simplifying robot hands using recursively scaled power grasps

This paper presents a concept for extending the functionality of robot hands so that they can better manipulate objects too small for an enveloping power grasp. Rather than pinching these objects between the fingertips of a hand, a miniature hand is embedded recursively on the end of a finger, enabling a power grasp on a smaller scale. The mechanics of designing such a gripper to operate without adding additional tendons are analyzed within the framework of underactuated elastic mechanisms. A simplified robot hand is demonstrated having a recursive gripper, and the process of picking up a pen and writing using a multi-scale grasp is demonstrated.