Multi-scale time series analysis using TT-ConvLSTM technique for bearing remaining useful life prediction

Abstract

This study advocates the utilization of a parallel neural network (PNN) architecture for the estimation of remaining useful life (RUL) of rolling element bearings. Conventional machine learning methods have often fallen short in processing machinery sensor data efficiently and accurately, given its vast nature and the temporal dynamics of component health conditions. To address this limitation, a robust PNN architecture is proposed which incorporates multiple parallel processing pathways. These pathways are equipped with diverse input neurons, capturing data from mechanical component condition sensors. The output neuron then efficiently predicts the RUL, capturing the degradation stages throughout the component's lifespan. The PNN structure provides better accuracy and computation time by efficiently handling huge amounts of data simultaneously and integrating both spatial and temporal information present. Additionally, time-transformer and recurrent neural networks (RNNs) are used to handle complex time series data. Improvement methodologies, such as positional encoding combined with a multi-headed self-attention mechanism and the convolutional long short-term memory (ConvLSTM) neural network, are employed. These methodologies adeptly handle spatiotemporal dependencies inherent in multidimensional features extracted across the time domain, frequency domain, and time–frequency domain, thereby considerably boosting the model's efficacy. Two case studies are conducted on XJTU-SY rolling element bearing dataset and FEMTO bearing dataset to validate and display the generalization capabilities of the proposed methodology, where PNN performed exceptionally in terms of accuracy and efficiency. It is concluded that with a novel implementation of variational stride temporal window strategy and utilizing the full capabilities of a PNN, the RUL of bearings can be predicted very accurately. The algorithm strategy is very robust and can be applied to other machine components as well. Subsequently, the code for the algorithm will be open-sourced.