2016 年 10 巻 9 号 p. JAMDSM0104
Aiming to solve the problems of distortion and incomplete decomposition by direct application of the original Local Mean Decomposition (LMD) to square wave alternating current (AC) welding arc signal, a LMD based on linear interpolation is proposed to investigate square wave AC welding current signal. Linear interpolation is introduced in LMD to obtain the local mean function and the local envelope function instead of the methods of moving average and spline interpolation. The superiority of the LMD based on linear interpolation is verified by the analysis of the simulation and experimental square wave alternating welding current signal. The results indicate that the proposed method not only can effectively decompose welding current signal into different compents related to welding quality, but also has the function of the noise reduction by reconstruction of the valid compents after correlation analysis. Meanwhile, the time-frequency distribution of the welding current signal is also obtained by the Hilbert transformation based on the decomposed results by LMD, which can effectively describe and estimate welding arc energy characteristics related to the welding quality.
