Underactuated Hand Design Using Mechanically Realizable Manifolds

TL;DR

This paper introduces a novel method for designing underactuated robotic hands by optimizing mechanically realizable manifolds to achieve desired grasps with minimal actuators, emphasizing grasp stability.

Contribution

It presents a new algorithm to determine hand synergies that are physically implementable and optimize grasp stability, advancing underactuated hand design.

Findings

Successfully designed a three-finger single-actuator hand.

Achieved stable grasps with fewer actuators.

Validated effectiveness through numerical and experimental tests.

Abstract

Hand synergies, or joint coordination patterns, have become an effective tool for achieving versatile robotic grasping with simple hands or planning algorithms. Here we propose a method to determine the hand synergies such that they can be physically implemented in an underactuated fashion. Given a kinematic hand model and a set of desired grasps, our algorithm optimizes a Mechanically Realizable Manifold designed to be achievable by a physical underactuation mechanism, enabling the resulting hand to achieve the desired grasps with few actuators. Furthermore, in contrast to existing methods for determining synergies which are only concerned with hand posture, our method explicitly optimizes the stability of the target grasps. We implement this method in the design of a three-finger single-actuator hand as an example, and evaluate its effectiveness numerically and experimentally.