Kinematic analysis and planning for form closure grasps by robotic hands

A new approach to the planning of form closure grasps by robotic hands is presented. The form closure grasp is to constrain a rigid workpiece by surrounding the object surface with mechanical fingers so that the object motion is geometrically constrained in all directions. First, kinematic conditions for the form closure grasp are obtained for workpieces with smooth surfaces, and are extended those one comprising edges and vertices. An efficient algorithm for examining the form closure grasp conditions is then developed by applying linear programming techniques. A computer-assisted planning system is also developed for the synthesis of grasping points as well as for the design of grippers. Fingertip locations are determined so as to accomplish the form closure grasp, given the geometry of a workpiece. A couple of examples demonstrate the usefulness of the method.