The Folding Hand: Anthropomorphic Robotic Hands With a Compact Reconfigurable Humanoid Palm Design

The human palm is a remarkable and highly functional part of the hand that significantly contributes to dexterity, grasp versatility, and overall manipulation capability. The metacarpophalangeal joints (MCP) of the palm facilitate movement of the fingers for flexion, extension, abduction, adduction, and limited circumduction, which can be a challenge to replicate the same function in robotic hands by simple design. In this letter, we proposed a single actuated folding mechanism as the metacarpals and passive rotating MCP joints to perform abduction, adduction, and circumduction of the human hand. The proposed anthropomorphic hand called Folding Hand which has a reconfigurable palm and five underactuated tendon-driven fingers. The design of the hand is compact and the price is low, with all six actuators and five sensors on the hand costing less than $180. Additionally, a methodology has been developed to comprehensively analyze the grasping capacity by combining the grasping quality and the grasping workspace. The experimental results show that the folding palm mechanism and the compliant rotating finger base can replicate human hand capabilities and performance precision and in-hand manipulation tasks.