关键词: 局部标准化, 邻域保持嵌入算法, 局部离群因子, 多模态过程系统, 监控模型

Abstract: Complex chemical processes often have multiple operating modes and the within-mode process data do not follow Gaussian or non-Gaussian distributions. To handle the problem of multiple operating modes and complex data distribution, a novel fault detection method, local standardized neighborhood preserving embedding (LSNPE) was proposed by applying local standardization (LS) strategy to the neighborhood preserving embedding (NPE) algorithm. Firstly, LSNPE algorithm was performed for dimensionality reduction and thus the main features of the collected data were extracted. At the same time, it could keep the neighborhood structure unchanged. Next, a monitoring statistics was established using the local outlier factor (LOF) of each sample in feature space and its control limit was determined. Instead of building multiple monitoring models for complex chemical process with different operating modes, the proposed LSNPE method built only one global model to monitor a multi-mode process without the support of any prior process knowledge. Finally, the feasibility and efficiency of the proposed method were illustrated through a numerical example and the Tennessee Eastman process.

Key words: local standardized, neighborhood preserving embedding algorithm, local outlier factor, multiple operating modes process system, monitoring model