Grasping and in-hand manipulation: experiments with a reconfigurable gripper

This paper addresses the problem of grasping and manipulating three-dimensi onal objects with a reconfigurable gripper equipped with two parallel plate s whose distance can be adjusted by a computer-controlled actuator. The bot tom plate is a bare plane and the top one carries a rectangular grid of act uated pins that can translate in discrete increments under computer control . We propose to use this gripper to immobilize objects through frictionless contacts with three of the pins and the bottom plate, and to manipulate an object within a grasp by planning the sequence of pin configurations that will bring this object to a desired position and orientation. A detailed an alysis of the problem geometry in configuration space was used in a previou s paper to devise simple and efficient algorithms for grasp and manipulatio n planning. We have constructed a prototype of the gripper and this paper p resents our experiments.