어텐션 메커니즘을 활용한 철도차량 공기압축기의 이상탐지

Abstract

Condition-based diagnostic analysis of air compressors of railway vehicles is essential for passenger safety and maintenance cost reduction. When conventional long short-term memory (LSTM) autoencoders are used for detecting anomalies in time series data, the input data cannot be reconstructed appropriately when the sequence length is large. Recently, the attention mechanism was proposed to solve this problem encountered in LSTM autoencoders. In the current study, the anomaly detection performance of railway vehicle air compressors was improved using the attention mechanism. The data reconstruction performance of the LSTM autoencoder model was compared with that of the LSTM autoencoder model with the attention mechanism and the transformer model comprising only the attention mechanism by using the sensor data of an air compressor of the Airport Railroad Express train in Seoul, Korea. For artificially generated abnormal data, three anomaly scenarios were successfully detected using the transformer model, which exhibited the best data reconstruction performance among the three models. The results confirmed that transformer models with attention mechanisms can detect anomalies in the air compressors of railway vehicles in a timely manner.