Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN

Abstract Proper lubrication is critical for ensuring the reliability and longevity of mechanical systems, yet its degradation due to factors like contamination or insufficient lubricant often leads to equipment failure. This study proposes a novel approach integrating Continuous Wavelet Transform (C...

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Main Authors: Haijie Yu, Haijun Wei
Format: Article
Language:English
Published: Nature Portfolio 2025-08-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-14593-w
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author Haijie Yu
Haijun Wei
author_facet Haijie Yu
Haijun Wei
author_sort Haijie Yu
collection DOAJ
description Abstract Proper lubrication is critical for ensuring the reliability and longevity of mechanical systems, yet its degradation due to factors like contamination or insufficient lubricant often leads to equipment failure. This study proposes a novel approach integrating Continuous Wavelet Transform (CWT) and Convolutional Neural Networks (CNN) for robust lubrication state identification. Vibration signals were collected from a pin-disk tribological system under three lubrication states: normal (NL), insufficient (IL), and contaminated (LC). CWT was applied to convert raw signals into time-frequency diagrams, which were preprocessed and input into a CNN model. The CNN architecture, comprising three convolutional layers, max pooling, and fully connected layers, was trained using the Adam optimizer with early stopping to prevent overfitting. Results demonstrated exceptional performance: the model achieved 99.8% training accuracy and 100% test accuracy, significantly outperforming traditional methods (RMS + CNN: 63.8%; PSD + CNN: 73.4%; CWT + SVM: 76.3%). t-SNE visualization confirmed distinct feature separation among lubrication states, and the confusion matrix revealed flawless classification on the test set. The method’s ability to capture time-frequency characteristics via CWT and leverage CNN’s deep feature learning offers a highly accurate and reliable solution for real-world lubrication monitoring.
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spelling doaj-art-735fc986d8bc4b3bb32bbc2db37b4cdf2025-08-20T04:01:51ZengNature PortfolioScientific Reports2045-23222025-08-0115111210.1038/s41598-025-14593-wLubrication state identification of vibration time-frequency characteristics based on CWT and CNNHaijie Yu0Haijun Wei1Yazhou Bay Innovation Institute, International Navigation College, Hainan Tropical Ocean UniversityMerchant Marine College, Shanghai Maritime UniversityAbstract Proper lubrication is critical for ensuring the reliability and longevity of mechanical systems, yet its degradation due to factors like contamination or insufficient lubricant often leads to equipment failure. This study proposes a novel approach integrating Continuous Wavelet Transform (CWT) and Convolutional Neural Networks (CNN) for robust lubrication state identification. Vibration signals were collected from a pin-disk tribological system under three lubrication states: normal (NL), insufficient (IL), and contaminated (LC). CWT was applied to convert raw signals into time-frequency diagrams, which were preprocessed and input into a CNN model. The CNN architecture, comprising three convolutional layers, max pooling, and fully connected layers, was trained using the Adam optimizer with early stopping to prevent overfitting. Results demonstrated exceptional performance: the model achieved 99.8% training accuracy and 100% test accuracy, significantly outperforming traditional methods (RMS + CNN: 63.8%; PSD + CNN: 73.4%; CWT + SVM: 76.3%). t-SNE visualization confirmed distinct feature separation among lubrication states, and the confusion matrix revealed flawless classification on the test set. The method’s ability to capture time-frequency characteristics via CWT and leverage CNN’s deep feature learning offers a highly accurate and reliable solution for real-world lubrication monitoring.https://doi.org/10.1038/s41598-025-14593-wLubrication state identificationContinuous wavelet transformConvolutional neural networkTime-frequency characteristics
spellingShingle Haijie Yu
Haijun Wei
Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
Scientific Reports
Lubrication state identification
Continuous wavelet transform
Convolutional neural network
Time-frequency characteristics
title Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
title_full Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
title_fullStr Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
title_full_unstemmed Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
title_short Lubrication state identification of vibration time-frequency characteristics based on CWT and CNN
title_sort lubrication state identification of vibration time frequency characteristics based on cwt and cnn
topic Lubrication state identification
Continuous wavelet transform
Convolutional neural network
Time-frequency characteristics
url https://doi.org/10.1038/s41598-025-14593-w
work_keys_str_mv AT haijieyu lubricationstateidentificationofvibrationtimefrequencycharacteristicsbasedoncwtandcnn
AT haijunwei lubricationstateidentificationofvibrationtimefrequencycharacteristicsbasedoncwtandcnn