Organizations: Farmer School of Business, Miami University, OH. USA · School of Mathematics & Statistics, Wuhan University, Hubei, China · Miami Herbert Business School, University of Miami, FL. USA · Sauder School of Business, The University of British Columbia, BC. Canada
Smart manufacturing processes are often installed with a large number of sensors, imaging devices and computers, which not only enable instant communication across various modules of a production system but also aid in intelligent manufacturing management. In this paper, we introduce MODERN, a deep learning framework for quality monitoring and fault isolation, which integrates these enhanced capabilities into the practice of industrial quality control. Using the architecture of an inception residual neural network, we develop a control chart that monitors the likelihood of a product containing defects. We also propose a faulty region estimator that identifies the defective area using transfer learning. To extend our framework to cases where there are not sufficient training data, we suggest a transfer monitoring technique that requires only a small sample size and a hypothesis testing approach for quantitatively assessing the applicability of our method. Theoretically, we establish the minimax optimal convergence rate for both our defect likelihood estimation and fault diagnosis. Our results lead to a seemingly counter-intuitive managerial implication - it may not always be in a manufacturer's best interests to keep upgrading its monitoring equipment regardless of the cost. Empirically, we demonstrate the superior performance of our method in comparison with a state-of-the-art approach using both simulated experiments and real data.
Figures & tables
Figure 1: An illustration for the insufficiency of the existing image-based quality monitoring.
Figure 2: Graphical illustration of filter concatenation and residual connection in a generic inception module.
Figure 3: The complete schematic view of MODERN-Net architecture.
Figure 4: Simulated IC (left) and OC (right) image
Shift size
Low
Medium
High
1
0.46
0.47
0.47
2
0.59
0.51
0.46
3
1.00
0.96
0.46
Table 1: The impact of image resolution on classification accuracy.
Class
ARL 1
sdARL 1
Prop.Early
Prop.On
SDSC
sdSDSC
1
20.64
0.2533
0.02
0.98
0.8293
0.0280
2
20.96
0.0400
0.01
0.99
0.7157
0.0270
3
21.00
0.0000
0.00
1.00
0.7974
0.0131
4
20.82
0.1218
0.03
0.97
0.7696
0.0348
5
21.00
0.0000
0.00
1.00
0.8719
0.0135
6
21.00
0.0000
0.00
1.00
0.6548
0.0425
Table 2: The numerical performance of the proposed method on the DAGM testing set.
Figure 5: Performance of MODERN-Diagnosis: Estimated vs true faulty regions.
Fault Type
Method
ARL 1
sdARL 1
Prop.On
SDSC
sdSDSC
MODERN
21.00
0.0000
1.00
0.6286
0.0084
1
MF
153.75
6.7987
0.01
0.0000
0.0000
t-stat
19.5258∗∗
74.8333∗∗
MODERN
21.00
0.0000
1.00
0.6208
0.0057
2
MF
150.58
6.3956
0.00
0.5762
0.0097
t-stat
20.2608∗∗
3.9642∗∗
Table 3: Comparison between MODERN framework and the MF method in simulated experiments.
Figure 6: Comparison between MODERN framework and MF method in electric commutator manufacturing.
Figure 7: Comparison between MODERN framework and MF method in leather manufacturing.
Appendix figures & tables9 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 8: Sample DAGM images: examples of IC and OC images.
Figure 9: The training progression of F(⋅;V) (left) and G(⋅;U) (right) as the number of epochs increases.
Figure 10: Representative images in the AR simulated example.
Figure 11: The histogram of the applicability test in which F(⋅;V) is applied to 500 IC images and the two types of OC images (500 each type) generated by the AR model.
Figure 12: Fault isolation results give by MODERN-Diagnosis and the MF method in simulations.
Figure 13: Representative images in the electric commutator manufacturing.
Figure 14: The histogram of the applicability test for the commutator images
Layer
Size
Kernel Size
Stride
Pad
Input Image
512×512×3
Convolution 1
128×128×96
11×11×3
4
2
Batch Norm 1
128×128×96
Leaky ReLU 1
128×128×96
Max Pooling 1
63×63×96
3×3
2
0
Convolution 2
63×63×256
5×5×96
1
2
Appendix
Table 4: The architecture of AlexNet.
Specificity
Sensitivity
Class
MODERN
AlexNet
MODERN
AlexNet
1
100%
100%
100%
100%
2
100%
100%
100%
100%
3
100%
100%
100%
100%
4
100%
98.63%
100%
42.31%
5
100%
100%
100%
90.48%
Appendix
Table 5: Performance comparison with AlexNet using DAGM.
Fault diagnosis identifies, localizes, and explains failures in engineered and computational systems using sensor data, logs, models, and domain knowledge.
Birmingham City University, UK · the Helen and John C. Hartmann Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, NJ 07102, USA