Static Grasp Stability Analysis of Two Spatial Objects Including Contact Surface Geometry

Abstract

Multifingered robot hands have the potential to execute dexterous and fine manipulation of multiple objects. This paper analyzes the grasp stability of two spatial objects to enhance the dexterity of the hands. The stability is investigated using the potential energy method, in which the grasp is replaced with a linear spring model. A grasp stiffness matrix is analytically derived by including the contact surface geometry (metric tensor, curvature, and torsion) and contact condition (frictionless sliding contact and frictional rolling contact). The grasp stability is evaluated using the eigenvalues of the matrix, and the displacement mode of the grasp is derived by its corresponding eigenvectors. The effectiveness of this analysis is demonstrated through numerical examples.