A Symmetry Theory of Planar Grasp

Abstract

A theory for identification and classification of two-fingered grasps is described and demonstrated. It is shown that optimal finger positions are obtained from the pairwise intersections of three subsets in the configuration space for the gripper: the symmetry and antisymmetry sets, and the critical set of the grasp map. Furthermore the three sets themselves form boundaries in a natural partition of configuration space. The partition corresponds to a classification of possible grasps according to their stability properties. An implementation of the theory has been developed for an ADEPT robot with visual sensing.