“…Therefore, many researchers have introduced neural networks into the field of fault diagnosis [ 2 , 3 ] and achieved automatic fault diagnosis based on deep learning. Deep learning methods, such as Convolutional Neural Networks [ 4 , 5 ], DBNs (Deep Belief Networks) [ 6 , 7 ], Generative Adversarial Networks [ 8 , 9 ], Recurrent Neural Networks [ 10 , 11 ], and Deep Autoencoder [ 12 , 13 ], by automatically and efficiently extracting feature information, overcome several limitations of traditional diagnostic methods and significantly improve the diagnostic accuracy. Among them, the typical BP (Back Propagation) neural network is widely used in the field of fault diagnosis, such as automobile transmission systems, engines, and hydraulic power steering systems [ 14 – 17 ].…”