Application of arc plasma spectral information in the monitor of Al-Mg alloy pulsed GTAW penetration status based on fuzzy logic system

In this paper, an intelligent fuzzy system based on arc spectral information was proposed to recognize the weld penetration status. A spectrometer and a visual sensor were used simultaneously to collect the arc spectral and visual information about the Al-Mg alloy pulsed GTAW process, respectively. Principal component analysis was utilized for spectral line identification, redundancy removal and spectral characteristic signals extraction; wavelet packet denoising technique was used to filter these signals. The relationship between the penetration status under different welding conditions and the corresponding spectral signals was discussed and clarified. Finally, a fuzzy system based on the spectral signals was developed and successfully used to estimate the percentage index of the weld penetration status. With a binary decision of penetration index, the average recognition rate for the penetration status about the specific welding conditions was no less than 82.1 %.