Push-pull wire feeding system of welding based on TMS320F2812 and servo system

Objective At the end of short circuit transition stage of CO₂ arc welding, pulling back welding wire could reduce the generation of spatter. To achieve the wire feeding and pulling process under the high-frequency short circuit transition of CO₂ arc welding, a wire feeding system that could achieve the push pull wire feeding process was built with a digital signal processor TMS320F2812 and a low inertia servo motor system. Methods Based on periodic characteristics of sine function, a curve of speed change of servo motor during the process of feeding and pulling back welding wire was designed. And based on the relationship between actual feeding distance of welding wire per cycle, short circuit transition frequency and melting rate of welding wire, as well as mathematical analysis, the design of motor speed curve was further optimized and improved. Results Based on “pulse + signal” control method in servo motor position control mode, push-pull wire feeding process is achieved by changing pulse signal frequency to control motor to move according to the designed speed curve. The actual wire feeding system may experience mechanical resonance, which can be avoided by adjusting calculation parameters of speed curve. Conclusion This push-pull wire feeding system can achieve a stable push-pull wire feeding process with a maximum frequency of 75 Hz.