Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System
Degraded electrodes in a resistance spot welding system should be replaced to ensure that weld quality is maintained. Welding electrodes are subjected to different environmental and operational loading conditions during use. When they are replaced with a fixed interval, replacement may occur too ear...
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| Format: | Article |
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MDPI AG
2020-08-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/10/17/5860 |
| _version_ | 1797555913214656512 |
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| author | Wonho Jung Hyunseok Oh Dong Ho Yun Young Gon Kim Jong Pil Youn Jae Hong Park |
| author_facet | Wonho Jung Hyunseok Oh Dong Ho Yun Young Gon Kim Jong Pil Youn Jae Hong Park |
| author_sort | Wonho Jung |
| collection | DOAJ |
| description | Degraded electrodes in a resistance spot welding system should be replaced to ensure that weld quality is maintained. Welding electrodes are subjected to different environmental and operational loading conditions during use. When they are replaced with a fixed interval, replacement may occur too early (raising maintenance costs) or too late (leading to quality issues). This motivates condition monitoring strategies for resistance spot welding electrode tips. Thus, this paper proposes a modified recurrence plot (RP) for robust condition monitoring of welding electrode tips in resistance spot welding systems. The overall procedure for the proposed condition monitoring approach consists of three steps: (1) transformation of a one-dimensional signal to a two-dimensional image, (2) unsupervised feature extraction with LeNet architecture-based convolutional neural networks, and (3) health indicator calculation. RP methods convert dynamic resistance waveforms to RPs. The original RP method provides an image with binary-colored pixels (i.e., black or white) that makes this method insensitive to the change of the waveform signal. The proposed RP method is devised to be sensitive to the change of the waveform signal, while enhancing robustness to external noise. The performance of the proposed RP method is evaluated by examining simulated aperiodic waveform signals with and without external noise. A case study is presented to examine the proposed method’s ability to monitor the condition of resistance spot welding electrodes. The results show that the proposed method outperforms handcrafted, feature-based condition monitoring methods. This study can be used to accurately determine the lifetime of welding electrodes in real time during the spot welding process. |
| first_indexed | 2024-03-10T16:54:15Z |
| format | Article |
| id | doaj.art-b876cafcf550408f9b6ebf9b04f86581 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T16:54:15Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-b876cafcf550408f9b6ebf9b04f865812023-11-20T11:12:41ZengMDPI AGApplied Sciences2076-34172020-08-011017586010.3390/app10175860Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding SystemWonho Jung0Hyunseok Oh1Dong Ho Yun2Young Gon Kim3Jong Pil Youn4Jae Hong Park5School of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, KoreaSchool of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, KoreaSmart Mobility Materials and Components R&D Group, Korea Institute of Industrial Technology, Gwangju 61012, KoreaSmart Mobility Materials and Components R&D Group, Korea Institute of Industrial Technology, Gwangju 61012, KoreaIoT/Data Business Division, SK Telecom, Seoul 04539, KoreaIoT/Data Business Division, SK Telecom, Seoul 04539, KoreaDegraded electrodes in a resistance spot welding system should be replaced to ensure that weld quality is maintained. Welding electrodes are subjected to different environmental and operational loading conditions during use. When they are replaced with a fixed interval, replacement may occur too early (raising maintenance costs) or too late (leading to quality issues). This motivates condition monitoring strategies for resistance spot welding electrode tips. Thus, this paper proposes a modified recurrence plot (RP) for robust condition monitoring of welding electrode tips in resistance spot welding systems. The overall procedure for the proposed condition monitoring approach consists of three steps: (1) transformation of a one-dimensional signal to a two-dimensional image, (2) unsupervised feature extraction with LeNet architecture-based convolutional neural networks, and (3) health indicator calculation. RP methods convert dynamic resistance waveforms to RPs. The original RP method provides an image with binary-colored pixels (i.e., black or white) that makes this method insensitive to the change of the waveform signal. The proposed RP method is devised to be sensitive to the change of the waveform signal, while enhancing robustness to external noise. The performance of the proposed RP method is evaluated by examining simulated aperiodic waveform signals with and without external noise. A case study is presented to examine the proposed method’s ability to monitor the condition of resistance spot welding electrodes. The results show that the proposed method outperforms handcrafted, feature-based condition monitoring methods. This study can be used to accurately determine the lifetime of welding electrodes in real time during the spot welding process.https://www.mdpi.com/2076-3417/10/17/5860spot weldingcondition monitoringfeature engineeringwaveform imaging |
| spellingShingle | Wonho Jung Hyunseok Oh Dong Ho Yun Young Gon Kim Jong Pil Youn Jae Hong Park Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System Applied Sciences spot welding condition monitoring feature engineering waveform imaging |
| title | Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System |
| title_full | Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System |
| title_fullStr | Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System |
| title_full_unstemmed | Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System |
| title_short | Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System |
| title_sort | modified recurrence plot for robust condition monitoring of electrode tips in a resistance spot welding system |
| topic | spot welding condition monitoring feature engineering waveform imaging |
| url | https://www.mdpi.com/2076-3417/10/17/5860 |
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