Abstract
Automatic uderwater welding is basic technology to improve cost performance of offshore construction and maintenance. The most important point to keep high weld quality is precise nozzle positioning. Several visual seam tracking methods have been considered to realize autonomous control system. Two typical methods are light cutting method by slit laser beam and ultra sonic imaging technique. Light cutting method is potential method for shape recognition in air condition. Water proofed containers for laser emitter and video camera was prepared for underwater seam tracking of weld line in turbid water. Good seam tracking could be carried out even in turbid water by attached container to shorten the actual light path. Another trial to get clear image by ultrasonic imaging was also reasonable in turbid water.
