The Research Of The Weld Seam Tracking Control System Based On Arc Sensor

In modern welding industry, with the continuous improvement of automation and intelligent levels, welding seam tracking technology has become one of the key technologies of the automatic welding process. Based on the study of the arc sensors theory model, considering the characteristics of CO₂ welding melt transition and by extracting and analysing the current signals of the swing-type arc sensors, this paper proposes welding seam tracking and control system which can achieve welding path and crevasses borderline identification. This system quite adapts to welding production about large dimension welding seam and diversified shape crevasses.This paper firstly established a static model about CO₂ welding arc sensor by experiment, and educed the connection coefficient between welding current and welding torch height. Thus, the parameters of borderline identification and welding seam tracking can achieved by detect welding torch height which welding current' change reflected. In order to produce a high-performance, low-cost, economic-type welding seam tracking system, we used a SCM with very high performance-price ratio, PIC16F877, produced by Mircochip Corporation. With the PIC chip as the main control modules, designed the external circuits of the tracking and control system, including the signal acquisition, processing circuits and the driving circuits of the executing organs, and determined the software structure and thoughtway based on these hardware curcuits.Considering the short-circuit transitted CO₂ gas-protected welding process would inevitably be affected by all kinds of interfering factors, we extracted and disposed the arc current signals by discrete integral determinant method, based on hardware filter, improved the tracking accuracy of the entire system. The stepper motor is used as the executing organs of the tracking system, because of its characteristics of real-time, easy controlled, small inertia...