The concept, theory, and the issues that are pertinent to the design and implementation of an adaptive real-time, intelligent seam tracker (ARTIST) are discussed. ARTIST is designed to operate in the unstructured environment of 3-D seams without preprogramming. A salient feature of the ARTIST design is that the tracking errors in any cycle do not affect the system performance during subsequent cycles. The conceptual and analytical development of a two-tier hierarchical control scheme for ARTIST is presented. The high-level controller models and interacts with the global seam environment while the low-level controller positions the torch over the seam with the correct orientation.>

For pt.I see ibid., p.1904-9 (1990). The design and implementation issues for ARTIST (adaptive real-time intelligent seam tracker), which is essentially a microcomputer-based single-pass system characterized by the absence of an additional teaching phase, are addressed. ARTIST uses a welding torch and a laser-ranging sensor mounted on the end-effector of a six-axis robot. Sources of error that could potentially contribute to inaccuracy in the seam tracking process are discussed. Suggestions are also made for enhancing the performance and applicability of ARTIST for welding automation.>

The paper presents the concept of a real-time seam tracking system for welding automation and the initial design for building a prototype. The ARTIST - Adaptive Real-Time Intelligent Seam Tracker - uses a robot-held, laser based vision system for automation of arc welding processes, and is currently under development at the Applied Research Laboratory of The Pennsylvania State University. The design of ARTIST builds upon the concept of a zero-pass technique where 3D information of the seam geometry is collected and processed for real time guidance and control of the welding torch trailing behind the laser-based vision sensor. This zero-pass concept eliminates the need for pre-programming of the weld path and thus potentially enhances the welding cycle time for small batches. The ARTIST is designed to support multipass arc welding and to handle any tack welds which are encountered during the seam welding operation.