关键词: 材料合成与加工工艺, CO₂焊, 小波变换, 缩颈, 降噪

Abstract: Two characteristic features of the wavelet analysis was applied in the CO₂ welding voltage control. Firstly, based on the relationship between the signal local singularity and the wavelet transform modulus maximum, the welding voltage signal singularity was detected, resulting in the successful detection of the welding voltage mutation point and its degree. It can be used to extract the waveform characteristics of the welding voltage and the characterizing information about the liquid bridge pinch. Secondly, making use of the good time frequency characteristics of the wavelet analysis in the signal processing, the wavelet softthreshold filtering of the swing CO₂ welding voltage signal under the arc discharge sense was carried out, showing the possibility of removing the peak current of the shortcircuit transition and improving the signal-to-noise ratio.

Key words: materials synthesis and processing technology, CO₂ welding, wavelet transform, liquid bridge pinch, de-noise