Enabling Grasp Action: Generalized Evaluation of Grasp Stability via Contact Stiffness from Contact Mechanics Insight

TL;DR

This paper introduces a novel method for evaluating robotic grasp stability by modeling contact stiffness based on contact mechanics, providing a physics-informed metric that correlates well with existing indices.

Contribution

The paper develops a contact mechanics-based model to quantify grasp stiffness and proposes a new stability evaluation criterion validated through case studies.

Findings

The grasping stiffness matrix effectively captures contact properties.

The proposed stability measure correlates with standard grasp indices.

Validation confirms the approach's reliability in different grasp configurations.

Abstract

Performing a grasp is a pivotal capability for a robotic gripper. We propose a new evaluation approach of grasping stability via constructing a model of grasping stiffness based on the theory of contact mechanics. First, the mathematical models are built to explore soft contact and the general grasp stiffness between a finger and an object. Next, the grasping stiffness matrix is constructed to reflect the normal, tangential and torsion stiffness coefficients. Finally, we design two grasping cases to verify the proposed measurement criterion of grasping stability by comparing different grasping configurations. Specifically, a standard grasping index is used and compared with the minimum eigenvalue index of the constructed grasping stiffness we built. The comparison result reveals a similar tendency between them for measuring the grasping stability and thus, validates the proposed approach.