Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals

This study compared popular Deep Learning (DL) architectures to classify machining surface roughness using sound and force data. The DL architectures considered in this study include Multi-Layer Perceptron (MLP), Convolution Neural Network (CNN), Long Short-Term Memory (LSTM), and transformer. The c...

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Main Author: Binayak Bhandari
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Micromachines
Subjects:
Online Access:https://www.mdpi.com/2072-666X/12/12/1484
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author Binayak Bhandari
author_facet Binayak Bhandari
author_sort Binayak Bhandari
collection DOAJ
description This study compared popular Deep Learning (DL) architectures to classify machining surface roughness using sound and force data. The DL architectures considered in this study include Multi-Layer Perceptron (MLP), Convolution Neural Network (CNN), Long Short-Term Memory (LSTM), and transformer. The classification was performed on the sound and force data generated during machining aluminum sheets for different levels of spindle speed, feed rate, depth of cut, and end-mill diameter, and it was trained on 30 s machining data (10–40 s) of the machining experiments. Since a raw audio waveform is seldom used in DL models, Mel-Spectrogram and Mel Frequency Cepstral Coefficients (MFCCs) audio feature extraction techniques were used in the DL models. The results of DL models were compared for the training–validation accuracy, training epochs, and training parameters of each model. Although the roughness classification by all the DL models was satisfactory (except for CNN with Mel-Spectrogram), the transformer-based modes had the highest training (>96%) and validation accuracies (≈90%). The CNN model with Mel-Spectrogram exhibited the worst training and inference accuracy, which is influenced by limited training data. Confusion matrices were plotted to observe the classification accuracy visually. The confusion matrices showed that the transformer model trained on Mel-Spectrogram and the transformer model trained on MFCCs correctly predicted 366 (or 91.5%) and 371 (or 92.7%) out of 400 test samples. This study also highlights the suitability and superiority of the transformer model for time series sound and force data and over other DL models.
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spelling doaj.art-becf86b21a05449391f7818c6774ddfa2023-11-23T09:35:59ZengMDPI AGMicromachines2072-666X2021-11-011212148410.3390/mi12121484Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force SignalsBinayak Bhandari0Department of Railroad Engineering & Transport Management, Woosong University, Daejeon 300718, KoreaThis study compared popular Deep Learning (DL) architectures to classify machining surface roughness using sound and force data. The DL architectures considered in this study include Multi-Layer Perceptron (MLP), Convolution Neural Network (CNN), Long Short-Term Memory (LSTM), and transformer. The classification was performed on the sound and force data generated during machining aluminum sheets for different levels of spindle speed, feed rate, depth of cut, and end-mill diameter, and it was trained on 30 s machining data (10–40 s) of the machining experiments. Since a raw audio waveform is seldom used in DL models, Mel-Spectrogram and Mel Frequency Cepstral Coefficients (MFCCs) audio feature extraction techniques were used in the DL models. The results of DL models were compared for the training–validation accuracy, training epochs, and training parameters of each model. Although the roughness classification by all the DL models was satisfactory (except for CNN with Mel-Spectrogram), the transformer-based modes had the highest training (>96%) and validation accuracies (≈90%). The CNN model with Mel-Spectrogram exhibited the worst training and inference accuracy, which is influenced by limited training data. Confusion matrices were plotted to observe the classification accuracy visually. The confusion matrices showed that the transformer model trained on Mel-Spectrogram and the transformer model trained on MFCCs correctly predicted 366 (or 91.5%) and 371 (or 92.7%) out of 400 test samples. This study also highlights the suitability and superiority of the transformer model for time series sound and force data and over other DL models.https://www.mdpi.com/2072-666X/12/12/1484sound feature extractionprecision machiningDeep LearningCNNLSTMMLP
spellingShingle Binayak Bhandari
Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
Micromachines
sound feature extraction
precision machining
Deep Learning
CNN
LSTM
MLP
title Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
title_full Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
title_fullStr Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
title_full_unstemmed Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
title_short Comparative Study of Popular Deep Learning Models for Machining Roughness Classification Using Sound and Force Signals
title_sort comparative study of popular deep learning models for machining roughness classification using sound and force signals
topic sound feature extraction
precision machining
Deep Learning
CNN
LSTM
MLP
url https://www.mdpi.com/2072-666X/12/12/1484
work_keys_str_mv AT binayakbhandari comparativestudyofpopulardeeplearningmodelsformachiningroughnessclassificationusingsoundandforcesignals