Grasp stability analysis of two objects by considering contact surface geometry in 3D

This paper analyzes the grasp stability of two objects in three dimensions to enhance the dexterity of multifingered robot hands. The stability is investigated from the potential energy method in which the grasp is replaced with virtual spring model. A grasp stiffness matrix is analytically derived by including contact surface geometry (metric tensor, curvature and torsion) and contact condition (frictionless sliding and frictional rolling contacts). The grasp stability is evaluated by using the eigenvalues of the matrix, and the displacement motion direction of the grasp is derived by its corresponding eigenvectors. The effectiveness of this analysis is demonstrated through numerical examples.