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Orthogonal projection based statistical feature extraction for continuous process monitoring
  • +1
  • Cheng Ji,
  • Fangyuan Ma,
  • Jingde Wang,
  • Wei Sun
Cheng Ji
Beijing University of Chemical Technology College of Chemical Engineering
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Fangyuan Ma
Beijing University of Chemical Technology College of Chemical Engineering
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Jingde Wang
Beijing University of Chemical Technology College of Chemical Engineering
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Wei Sun
Beijing University of Chemical Technology College of Chemical Engineering

Corresponding Author:[email protected]

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Abstract

Multivariate statistical techniques have been widely applied in industrial processes to detect abnormal behaviors, while their performance could be unsatisfactory due to insufficient extraction of complex data characteristics. A method named Orthogonal transformed statistics Mahalanobis distance (OTSMD) is developed to handle this issue. As a feature-based method, OTSMD simultaneously considers various data characteristics through monitoring statistical features of process variables. Orthogonal transformed components (OTCs) are first calculated to capture variable correlation, and a set of statistical features is determined to extract other crucial characteristics, especially for the process nonstationarity. Statistical features of OTCs, which reveals implied process information, are continuously obtained using a sliding window, and a Mahalanobis distance index is utilized for fault detection. Compared with existing methods, OTSMD extracts data characteristics more comprehensively with a lower dimension, making it more effective in monitoring various faults. The results are illustrated through a numerical example, and two chemical industrial processes.