Abstract: Pulsed double-electrode metal inert gas welding is a new kind of low heat input welding method. With different connection, parts of welding current bypassed and it controlled the base metal current and melting current separately. With free-flight metal transfer process, it could weld dissimilar metals. Aiming at the unstability of coupling arc in pulsed double-electrode metal inert gas welding process, a dynamic mathematic model has been built to truly describe and simulate the welding process with equivalent simplification, linearization and iterative solution. Then a control scheme is put forward and simulated, which changes the wire feed speed to adjust the main arc length, and further to control the stability of the coupling arc. Also the welding experiments with control scheme are carried based rapid prototyping system. Simulations proved the effectiveness of control scheme. And with controlling, the welding experiment is more stable and a good Al-Fe joint is acquired.

Key words: control, metal inert gas(MIG) welding, modeling, pulsed double-electrode