1. Unsupervised fault detection in automated sequential manufacturing processes through image analysis and convolutional LSTM-based next visual status prediction.
- Author
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Yu, Na Hyeon and Baek, Sujeong
- Subjects
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STATISTICAL process control , *MANUFACTURING processes , *IMAGE analysis , *DISCRETE systems , *INFORMATION & communication technologies - Abstract
With the advancement of information and communication technology, the integration of smart systems into discrete sequential processes has been realized in manufacturing systems. Specifically, to optimize the efficiency of operations and production, accurate and rapid detection of faults is crucial. Numerous studies have attempted to identify faults in various electromechanical systems; however, the performance and effectiveness often depend on the quality of the collected signals and the system operation methodology. For instance, the measurements of various types of analog sensor signals—such as voltage, current, 3-axis acceleration, and temperature—vary according to the installation locations and positions within a system. Moreover, although an automated manufacturing system typically operates under predefined control sequences, identifying common signal patterns for every healthy or faulty state is challenging. Consequently, we focused on detecting faults using only image data captured from on-site camera in automated sequential manufacturing processes, without relying on additional manufacturing information. We proposed a method based on convolutional long short-term memory (LSTM) networks for the next visual status prediction and an unsupervised statistical process control chart to classify the current status as normal or faulty. Following the detection of a fault, we conducted unsupervised fault type clustering to provide valuable insights for maintenance efforts. The validation and verification demonstrated accurate fault detection (94.2%) and effective fault type clustering in two distinct manufacturing processes of a USB packaging system. Since no information other than the original process images captured by the on-site camera were used for fault detection and fault type classification, it can be assumed that the proposed methodology can be easily applied to other or more complex manufacturing processes. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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