US 12,339,654 B2
Unsupervised fault diagnosis method for mechanical equipment based on adversarial flow model
Jun Wang, Suzhou (CN); Jun Dai, Suzhou (CN); Xingxing Jiang, Suzhou (CN); Weiguo Huang, Suzhou (CN); and Zhongkui Zhu, Suzhou (CN)
Assigned to SOOCHOW UNIVERSITY, Suzhou (CN)
Appl. No. 17/916,720
Filed by SOOCHOW UNIVERSITY, Suzhou (CN)
PCT Filed Oct. 12, 2021, PCT No. PCT/CN2021/123194
§ 371(c)(1), (2) Date Oct. 3, 2022,
PCT Pub. No. WO2023/044978, PCT Pub. Date Mar. 30, 2023.
Claims priority of application No. 202111138262.0 (CN), filed on Sep. 27, 2021.
Prior Publication US 2024/0353829 A1, Oct. 24, 2024
Int. Cl. G05B 23/02 (2006.01)
CPC G05B 23/0281 (2013.01) [G05B 23/024 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An unsupervised fault diagnosis method for mechanical equipment based on an adversarial flow model, comprising steps of:
(1) data preprocessing: converting a mechanical vibration signal into a frequency domain signal, and normalizing an amplitude value of the frequency domain signal into a range of [0, 1];
(2) prior distribution designing: designing a mixture of Gaussian distribution with K subdistributions, wherein K is determined by the number of mechanical equipment status;
(3) model construction: constructing an unsupervised fault diagnosis model by combining an autoencoder, a flow model, and a classifier;
(4) model training: training the unsupervised fault diagnosis model by using various classes of status data, along with the designed prior distribution, preset training steps, loss functions, and an optimization algorithm; and
(5) fault diagnosis: inputting status data of mechanical equipment into the trained unsupervised fault diagnosis model to obtain a data clustering result and a fault diagnosis result,
wherein in step (3), the autoencoder is constructed by an encoder and a decoder, low-dimensional features of inputted data are learned by using the encoder, dimensionality of the low-dimensional features is the same as the dimensionality of the designed mixture of Gaussian distribution, and the inputted data is reconstructed by inputting the low-dimensional features into the decoder; the flow model maps the low-dimensional features of the inputted data into a Gaussian distribution with the same dimensionality as the low-dimensional features, and obtains mapped features; a combination of the autoencoder and the flow model is called a feature extractor; and
the classifier classifies the mapped features and prior features separately.