摘要 |
PROBLEM TO BE SOLVED: To correctly arrange a branch pipe on the circumferential surface of a main pipe, and to automatically weld the branch pipe to the main pipe in a short period of time without any skill of a worker.SOLUTION: In a welding method for arranging the branch pipe (12) with one end face (13) thereof grooved is arranged on the circumferential surface of the main pipe (11) and welding the branch pipe (12) to the main pipe (11), the end face of the branch pipe is imaged by an imaging unit while the sight line (40) of the imaging unit (39) is made coaxial with the branch pipe. The image of the end face of the branch pipe is extracted as an ellipse from the image picked up by the imaging unit, and the center of the extracted ellipse and the phase angle around the center with respect to the predetermined reference attitude are calculated. The branch pipe is rotated around the center line of the branch pipe determined from the center on the basis of the calculated phase angle. The branch pipe is moved till the end face of the branch pipe is brought into contact with the circumferential surface of the main pipe while maintaining the phase angle of the rotated branch pipe. The branch pipe is welded to the main pipe along the line at which the end face of the branch pipe is brought into contact with the main pipe. |