PURPOSE: To control profiling of a weld line with high accuracy and to permit high-quality welding with high efficiency by calculating and detecting the deviation of a welding head from the weld line from either of the inside circumference of a sensor position and the inside circumference of a pipe and feeding a correction signal to a driving device.
CONSTITUTION: The output signals of two sensors 111, 112 on an x-axis are 111=0, 112=1 when the circumference of the sensor position and the inside circumference 9 of the pipe deviate. The result of the calculation 111-112<0 is then outputted and the welding head moves to the position 111-112=0 with the x-axis as a forward direction. The output signals of the two sensors 113, 114 on the y-axis are 113=1, 114=0 in said position and the result of the calculation 113-114>0 is outputted. The welding head moves on the y-axis to the position 113-114=0. The result of the calculation 111-112<0 is outputted in this position and the welding head moves on the x-axis to the position 111-112=0. The deviation between the circumference 10 of the sensor position and the inside circumference 9 of the pipe is thereby kept within an error range of the sensor 11. The positioning control is thus ended.
HIROMI TSUNETAKA
YAMASHITA ICHIRO
