Time-Domain Characteristics Analysis of Penetration Arc Sound Signal in MIG Welding

2010 ◽  
Vol 154-155 ◽  
pp. 453-456
Author(s):  
Li Jun Liu ◽  
Qi Wang ◽  
Lan Hu

Many important time-domain characteristic parameters are extracted through the short-time analysis of arc sound signal in MIG butt welding with spray transfer, which can be used for the diagnosis on the weld penetration status. And the short-time autocorrelation function and short-time average amplitude difference function are adopted to pitch estimation. The analysis results show that the penetration status can be accurately recognized via the short-time energy, average magnitude, average zero-crossing and zero-to-energy and so on. Meanwhile, the pitch estimation of arc sound signal in experiments is at 220 points, that is 5 ms or 200 Hz in cycle. The methods and results provide a foundation for the diagnosis on penetration based on analysis of arc sound signal and have great theoretical meaning and practical value.

Author(s):  
Wenfu Wei ◽  
Chongliang Liang ◽  
Zefeng Yang ◽  
Pan Xu ◽  
Xin Yan ◽  
...  

In recent years, the speed and the current transmission density of high-speed railways are increased. As a result, the rate of the occurrence of pantograph–catenary arc also increases, which directly influences the service performance of the pantograph–catenary system. The detection and identification of the pantograph–catenary arc is of great significance for evaluating the off-line level to ensure the safe operation of the pantograph–catenary system. The currently used conventional optical arc detection method would be distorted by strong sunlight or other environmental lights in the actual operation, which would affect the accuracy of detection. On the contrary, the arc sound signal is not affected by the diurnal variation and can be easily obtained; it can also be distinguished well from other interfering sounds. In this paper, a new method that uses the arc sound is proposed to realize the effective detection of the pantograph–catenary arc. The frequency spectrum and the intensity characteristics of the pantograph–catenary arc sound are analyzed. The results show that the frequency band of the arc sound signal is wide and mainly gets distributed at 5–17 kHz. The curve of the sound waveform is drawn by calculating the short-time average energy, which is used to obtain the arc’s starting time, duration, and intensity, for calculating the off-line rate.


2010 ◽  
Vol 97-101 ◽  
pp. 3948-3951 ◽  
Author(s):  
Li Jun Liu ◽  
Lan Hu

Arc sound signal in MIG welding contains plenty of welding information, which is an important signal source of weld penetration. Aiming at on-line monitoring of weld penetration, the relationship between arc sound signal and penetration is analyzed in time-frequency domain through a reasonable selection of sample data. The results show that the spectrum of arc sound signal and penetration status are highly correlative. The changes of penetration can accurately detected by variation of signal energy from 1500 Hz to 4500 Hz in welding process. The above experiments verify the feasibility of monitoring the penetration through arc sound signal and provides theory and application foundation for penetration adaptive control.


Speech is classified into voice, unvoiced and silence. The voice speech is the periodic vibration of vocal folds. Background noise affects the speech signals. In many speech applications calculation of pitch plays a major role. The paper proposes a pitch detection algorithm based on the short-time average magnitude difference function (AMDF) and the short-term autocorrelation function (ACF). Detecting the Pitch within the speech signal is important in most of all the speech related applications. Detection of Pitch is useful in identification of speaker. One solution to get detect with the pitch is by using the time domain algorithms. This paper gives idea about estimation and detection of pitch in time domain algorithm for different voice samples


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