Affiliations: [a] College of Information Science and Engineering, Northeastern University, Shenyang, China
| [b] School of Intelligent Engineering, Shenyang City University, Shenyang, China
Correspondence:
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Corresponding author. Ying Xie, College of Information Science and Engineering, Northeastern University, Shenyang, China. E-mail: [email protected].
Abstract: As modern industrial processes often have multiple production modes, multimode-process monitoring has become an important issue. In multimode processes, the operating condition may often switch among different modes. As a result, popular process monitoring methods such as principal component analysis (PCA) and partial least squares (PLS) method should not be directly applied because they are based on a fundamental assumption that the process only has one stable operating condition. In this paper, a novel multimode-process data-standardization approach called double-weighted neighborhood standardization (DWNS) is proposed to solve the problem of multimode characteristics. This approach can transform multimode data into approximately single-mode data, which follow a Gaussian distribution. By analyzing a concrete example, this study indicates that the DWNS strategy is effective for multimode data preprocessing. Moreover, a novel fault detection method called DWNS-PCA is proposed for multimode processes. Finally, a numerical example and the penicillin fermentation process are used to test the validity and effectiveness of the DWNS-PCA. The results demonstrate that the proposed data-standardization method is suitable for multimode data, and the DWNS-PCA process monitoring method is effective for detecting faults in multimode processes.
