A Kinematic Framework for Evaluating Pinch Configurations in Robotic Hand Design without Object or Contact Models

TL;DR

This paper introduces a kinematic evaluation framework for robotic hand pinch configurations that does not depend on object models or contact forces, enabling early-stage design analysis.

Contribution

It presents a novel method to evaluate pinch capability solely based on hand kinematics, facilitating comparison of different hand designs without object contact data.

Findings

The method accurately detects feasible pinch configurations from fingertip workspace interactions.

It enables evaluation of pinch capability without requiring object or contact force models.

Analyses on four hand structures reveal the impact of kinematic design on pinch performance.

Abstract

Evaluating the pinch capability of a robotic hand is important for understanding its functional dexterity. However, many existing grasp evaluation methods rely on object geometry or contact force models, which limits their applicability during the early stages of robotic hand design. This study proposes a kinematic evaluation method for analyzing pinch configurations of robotic hands based on interactions between fingertip workspaces. First, the reachable workspace of each fingertip is computed from the joint configurations of the fingers. Then, feasible pinch configurations are detected by evaluating the relationships between fingertip pairs. Since the proposed method does not require information about object geometry or contact force models, the pinch capability of a robotic hand can be evaluated solely based on its kinematic structure. In addition, analyses are performed on four different kinematic structures of the hand to investigate their impact on the pinch configurations. The proposed evaluation framework can serve as a useful tool for comparing different robotic hand designs and analyzing pinch capability during the design stage.