Remaining useful life prediction of pressure regulating shutoff valve based on feature fusion and bidirectional gated recurrent unit

In the bleed air system of the ARJ21 aircraft, pressure regulating shutoff valve (PRSOV) failures are common, and their failures can lead to disasters and economic losses. Accordingly, prediction of the degradation performance of PRSOV is crucial. This work proposes a life prediction method based on principal component analysis (PCA) and bidirectional gated recurrent units (BiGRUs) to achieve accurate prediction. After obtaining pressure data throughout the entire life of PRSOV, considering that the pressure required for PRSOV during the takeoff and climb phases is the most critical, data from this phase are selected for focused monitoring. Classical statistical feature extraction methods are used to extract features from the raw pressure data during the takeoff and climb phases. An empirical feature extraction method with low-pressure weighting is also proposed based on engineering practical experience. Feature fusion is performed using PCA based on these two types of features. Finally, BiGRU is utilized to model the fused degradation feature indicators and estimate the remaining service life of PRSOV. The results of the analysis of the full life data of PRSOV in ARJ21 aircraft indicated that the proposed method can effectively predict its remaining service life. The proposed method demonstrated higher prediction accuracy compared with the related prediction methods.