Research On Metal Transfer Control Of Pulsed MIG Welding

In modern production, the jointing technology has been widely applied, and it has become a vital production tool.As a high quality welding method, the pulsed MIG welding has become more and more important in industry production. Because the pulsed MIG welding complete the welding process through the metal transfer process, studying and controlling the metal transfer's mechanism have fairly important affects to balance the welding process, improve the shaped welding slot and reduce the splash.After analyzing the mechanism of metal transfer, a double closed loop control scheme is adopted to control the welding current and electric-arc voltage based on control target of metal transfer. As the inner loop can acquire accurate metal transfer current graph by controlling the welding current graph, the adaptive control is adopted to control the welding current. After particular the inner loop is analyzed, an equivalent discrete math model of the current loop is established and a self-adjust adjustor based on the model is designed.A pulsed MIG welding math model is established by analyzing dynamics characters and control performances of the welding system, and a simulation model of the control system is conducted based on MATLAB/Simulink platform. At the end, after the welding parameters of the metal transfer process are analyzed, an improved metal transfer control scheme is put forward to guarantee drop size stabilization, and the simulation model was used to compare the improved scheme with the normal scheme. The simulation results show that the improved scheme can reduce wasted energies.A pulsed MIG welding hardware control system is designed by choosing DSP as the control core, and a pulsed MIG welding soft control system is designed based on assemble language by adopting modularize design method.