Sketch: A simple-to-use programming system for visually guided robotic arc welding

Programmability, the principal advantage of a robot over traditional hard automation, may become more difficult to achieve when vision systems are used to enhance robot capabilities because such systems may add a significant level of complexity to the programming task. CAD/CAM data on which to base automatic program generation are expensive and unavailable in many applications, particularly in small batch or low volume manufacturing. The SKETCH automatic programming facility, described in this paper, is designed for use in programming a visually guided robotic arc-welding system in those applications for which CAD/CAM-based off-line robot programming is either infeasable or unavailable. This facility was developed as part of SRI's ongoing research into machine-vision-based guidance and control of robots for arc welding and is designed to allow a skilled welder to program the vision system quickly and easily by sketching on a graphics screen the cross section of the seam to be welded.