Recognition and Automatic Tracking of Weld Line in Welding of T-Joint of Pipes by an Autonomous Mobile Robot with Vision Sensor.

Abstract

An autonomous mobile robot with visual sensor and four driving axes for pipe welding was constructed. The robot can move along a pipe, and detect the weld line to be welded by a visual sensor. Moreover, in order to perform welding automatically, the welding torch can track the weld line of the pipes by rotating the robot head. In the case of welding of T-joints of pipes, the robot can detect the contact angle between the two base metals to be welded, and the torch angle changes according to the contact angle. As the result of a tracking test by the robot system, it was shown that the recognition of the geometry of the T-joint by the laser light section method and automatic seam tracking were possible. The average tracking error was approximately 0.3 mm and the torch angle could be always kept at the optimum angle.