Method and apparatus for robotic transfer of workpieces

Abstract

A robotic apparatus for positioning a tool or work hand that incorporates a compliant wrist effective to adjust to delicate but misaligned portions of the workpiece, comprising (a) structure for magnetically supporting a positioning member carrying a gripper tool; (b) pneumatic structure for selectively separating and floating the positioning member from said supporting structure to permit lateral adjustment of the positioning member in response to small forces received from the gripper tool as it carries out gripping; and (c) structure for locking the positioning member to the supporting structure upon completion of the desired lateral adjustment. A method of using such compliant wrist concept, comprising (a) magnetically suspending a positioning plate from a magnet, the plate carrying the gripper tool; (b) injecting a film of air between the interface of the magnet and plate to provide floating separation therebetween enabling ease of lateral movement; (c) closing a gripper tool about the part to be gripped causing any offcenter gripping forces to be translated back to the plate resulting in lateral movement in response thereto for seeking a centering position; and (d) upon achieving the desired centering position, deactivating the air injection to permit the magnet to lock the plate in position relative to the magnet for further robotic movement.