Real-Time Seam Tracking for Robotic Welding Via Registration-Based Deformation Estimation
Surag Balajepalli, Amrish Baskaran, Naik Shounak, Christopher Eubel, Abolfazl Meyarian, Andong Dai, Pradeep Rajendran, Katsu Yamane
Abstract
Arc welding induces thermal deformation that continuously displaces the seam path during execution, causing the robot to miss the joint on long seams. We present a real-time seam tracking system with three principal contributions: (1) a constrained ICP registration of live leading-laser scans against a prescan point-cloud prior combined with exponentially decaying spatial propagation; (2) a laser-line detection network retrained on 1,000 arc-on images, raising F1 from 0.59 (prescan baseline) to 0.84 on a held-out arc-on test set; and (3) an asynchronous execution architecture for ensuring that smooth joint commands are sent at the robot's control cycle (40 Hz) even with perception delays or interruptions. Internal testing confirms the system remains in the joint on 97 cm-long seams with less than 2 sec cycle-time overhead. Field deployment improved weld quality acceptance rate from 81% to 95-98%.