A Fuzzy Rule-Based Method for Seeking Stable Arc Condition under Short-Circuiting Mode of GMA Welding Process

An unstable arc during welding induces unsound bead, thus resulting in poor mechanical properties at the welded joints. One of the important factors affecting arc stability is the welding voltage/current combination. In practice, a proper combination is usually determined by performing off-line experiments, and no extensive work has been reported on developing on-line searching methods. The paper proposes a systematic on-line method for searching the proper voltage/current combination to provide a stable arc condition in the short-circuiting metal transfer mode. Because the relationship between such welding parameters and the resulting arc stability is excessively complex and non-linear, it is difficult to determine a proper voltage/current combination based on mathematical modelling. To overcome this difficulty, a fuzzy rule-based method is proposed so that the complexity and non-linearity of arc behaviour is effectively represented by adopting fuzzy linguistic rules. The fuzzy rules here are constituted...