Abstract: A self-optimizing intelligent control algorithm of current waveform parameters of CO₂ gas shielded arc welding is put forward.The synthetic influence of the characteristic parameters of the CO₂ arc welding droplet short circuit transfer process is taken into account in the control algorithm.The characteristic parameters synthetic value is taken for the quantitative evaluation and objective optimum function,which is used to describe and evaluate the short circuit transfer process of CO₂ arc welding in real time.Based on the basic values of the waveform parameters,a three stage fuzzy control algorithm is used to adjust and optimize the current waveform parameters to their optimum values.By this way,a two-input-three-output type fuzzy control system is turned into a two-input-single-output type fuzzy control system with multi channel switch characteristic.Under the fuzzy self-optimizing of current waveform parameters during the short-circuit and at the stage of arc igniting,the waveform parameters and welding variables are adjusted progressively to a matching state.Thus,the droplet transfer of the welding process will be controlled,and the stability of the droplet transfer and the synthetical performance of the welding process can be improved.