Abstract: A fully digital wire extension fuzzy control system for CO2 short-circuit welding is presented. The main component is a digital signal processor ASDP2181 of ADI company, and the digital fuzzy control system also is designed and embedded in digital signal processor. It includes the fuzzy controller module which is designed to modulate wire speed and the waveform parameters modulation module which is used to modulate waveform parameters for short circuit CO2 welding and output voltage of welding machine. The welding process experiment proves that this system can keep arc stability and weld appearance in spite of the change of wire extension by measuring and calculating the average welding current online and automatically adjusting wire speed and waveform control parameters. The change of wire extension can be compensated in 8～45 mm.

Key words: CO2 short-circuit welding, Digital control system, Digital signal processor　Fuzzy control