Development of digital gas metal arc welding system

This paper presents a relatively new method for achieving better welding results of gas metal arc welding (GMAW) system by using a decentralized control method. The GMAW system is an arc welding process which incorporates the power source of GMAW (PS-GMAW) with the wire feed unit (WFU). In this paper, the GMAW system is considered as two separated subsystems, those are PS-GMAW and the WFU. The mathematical modeling of PS-GMAW and WFU are presented. Based on two subsystems, a sliding mode controller is designed and applied to control the WFU meanwhile a proportional controller is designed and applied to control the PS-GMAW. Furthermore, two decentralized controllers have to be designed to control the welding arc of GMAW, be stable and control the output welding current and welding voltage for tracking the constant setting values accurately during the welding process, respectively. The simulation and experimental results are presented to show the effectiveness of the proposed controllers.