Development of an automatic arc welding system using SMAW process

This paper describes a developed automatic welding control system for alternating current shield metal arc welding. It replaces manual operations which require a well-trained technician. We derived a mathematical model of the welding control system and identified the value of the system parameters thereof. A fuzzy gain scheduling PID controller modulates the rate of an electrode feed mechanism that regulates arc current. The electrode feed rate mechanism with this controller driven by an AC servomotor can both compensate for the molting part of the electrode and the undesirable fluctuation of the arc length during welding operation. It can also be easily applied to any welding system whose electrode is consumed during the welding process. By maintaining the magnitude of the arc current at the desired value and ensuring the stability of the arc length, excellent welding performance can be obtained. The simulation and experimental results both show that this automatic welding control system, based on the fuzzy gain scheduling PID controller, can perform effectively.