METHOD OF FOLLOWING WELD GROOVE

PURPOSE:To perform following of weld groove by a welding torch properly and enable good arc welding by operating the quantity of control to be given to the center of oscillation using a proper gain coefficient pertinent to welding condition. CONSTITUTION:It is supposed that IA is the value of welding current when oscillation is made from a point 1S2 to a point 2S2, and I'A' is the value of welding current when movement is made to the left end during oscillation from a point 1Sn+1 to a point 2Sn+1 when the center of oscillation OSC is shifted from a desired position to the left by a distance d1. The value of welding current I''A'' when oscillation is made to the left end during oscillation from a point 1Sn+i+1 to a point 2Sn+i+1 when the center of oscillation OSC is shifted from a desired position by a distance d1 is read out. Gain coefficient is operated from the value of welding current and the distance d1. The quantity of control is operated using the gain coefficient, and outputted as the quantity of change of each joint of a robot. The center of oscillation OSC is shifted to keep desired relation with the center line of groove GC.