Abstract: The hierarchically intelligent control theory is applied in order to realize the fully digital control system for CO2 short-circuit welding. This system integrates the digital PI controller, fuzzy controller and expert system, which make control levels clearer and design scheme easier. The experimental results validate this system can attain ideal waveform control for CO2 short-circuit welding, increase welding arc stability, improve welding process adaptability for the wire extension change and control welding process intelligently.

Key words: CO2 short-circuit welding, Fully digital control, Hierarchically intelligent control