Manipulator welding apparatus with sensing arrangements for weld slam

Abstract

Manipulator apparatus with weld seam tracking capabilities is provided with a sensing hand attached to the manipulator arm. The manipulator apparatus traverses a taught welding path on a workpiece to determine any deviation between the workpiece path and the taught path. The sensing hand includes a projection unit for projecting an optical slit pattern onto the workpiece. The sensing hand also includes a path sensing unit including an objective lens and a fiber optic cable for receiving by reflection from the workpiece the projected optical slit pattern. The fiber optic cable is connected to a camera located remotely from the sensing hand. The image received by the camera is utilized by the manipulator apparatus to determine the deviation between the path traversed by the manipulator during sensing and the sensed workpiece path. The deviation is then utilized to calculate the workpiece path data. The calculated path data is then utilized by the manipulator apparatus to weld the desired weld seam with a welding hand attached to the manipulator arm. In a first arrangement, a welding hand and sensing hand are provided at a hand holder station at the work station adjacent the workpiece. The manipulator automatically and selectively exchanges the hands at the hand holder station in accordance with the particular programmed operation to be performed. In another arrangement, the manipulator arm carries a welding hand and a sensing hand. The sensing hand is movably controlled by the manipulator apparatus between an operative sensing position and an inoperative welding position.