Abstract: The paper presents an arc sensing method in GMAW welding process which in based on the characteristic of the arc self-regulation. The method can measure the profiles of single V butt joint and corner joint, moreover, it can be successfully used in the seam tracking control of GMAW welding process. Using are as a sensor, the method is more simple and lower cost than other sensors, it is very significant to develop its further application in practical production. A programmable weaving torch device has been developed, which can work in a variety of weaving patterns under the control of a computer. At same time, in the research work, a mathematical model on the are sensing method has been established in detail. It indicate theoretically the principle of sensing method, and lay a foundation of seam tracking control through welding arc.

Key words: Arc sensing, GMAW welding process, Seam tracking control