Abstract: The performance of prior automated welding systems has been limited by their inability to independently track and weld and by their inability to accurately determine the groove profile. The adaptive welding system disclosed herein includes a weld torch (20) adapted to be controllably positioned in at least two dimensions, and means (28,38) for tracking a workpiece seam (12) to be welded. The tracking means (28,38) is pivotably connected to the weld torch (20). Means (19,40) for pivoting the tracking means (28,38) relative to the weld torch (20) is included to permit both the tracking means (28,38) and the weld torch (20) to be independently maintained over the seam (12). The tracking means (28,38) monitors the seam (12) by optical triangulation of a rotating laser beam (60) projected against the workpieces. This rotating laser beam (60) crosses the seam twice during each cycle of the beam (60).