Remaining Useful Life Of Bearings Research Articles

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

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.

Research on Remaining Useful Life Prediction of Bearings Based on MBCNN-BiLSTM

For safe maintenance and to reduce the risk of mechanical faults, the remaining useful life (RUL) estimate of bearings is significant. The typical methods of bearings’ RUL prediction suffer from low prediction accuracy because of the difficulty in extracting features. With the aim of improving the accuracy of RUL prediction, an approach based on multi-branch improved convolutional network (MBCNN) with global attention mechanism combined with bi-directional long- and short-term memory (BiLSTM) network is proposed for bearings’ RUL prediction. Firstly, the original vibration signal is fast Fourier transformed to obtain the frequency domain signal and then normalized. Secondly, the original signal and the frequency domain signal are input into the designed MBCNN network as two branches to extract the spatial features, and then input into the BiLSTM network to further extract the timing features, and the RUL of bearings is mapped by the fully connected network to achieve the purpose of prediction. Finally, an example validation was performed on a publicly available bearing degradation dataset. Compared with some existing prediction methods, the mean absolute and root mean square errors of the predictions were reduced by “22.2%” to “50.0%” and “26.1%” to “52.8%”, respectively, which proved the effectiveness and feasibility of the proposed method.

An attention-based stacked BiLSTM framework for predicting remaining useful life of rolling bearings

Data-driven prognostic techniques have been widely implemented to accurately predicting the remaining useful life (RUL) of high-speed bearings. Accurate RUL estimation attributes to determining underlying relationship between bearing degradation progression and current health status. To achieve this, effective feature compression and optimal feature selection are significant challenges to be overcome. Therefore, in this paper a framework is developed which utilizes the ‘Stacked Bi-directional Long Short Term Memory’ (SBiLSTM) with attention mechanism (A-SBiLSTM) to determine the underlying relationship between the health status and RUL of bearing. Bi-directional LSTM is capable of processing the past and the future states simultaneously thereby mining the useful degradation information from time-series data. Additionally, fitness analysis is carried out using feature ranking metrics to select features highly correlated with bearing degradation. The effectiveness and feasibility of the proposed methodology are experimentally validated and generalized on dataset from PRONOSTIA platform. The comparison results based on root mean square error (RMSE), and mean absolute error (MAE) achieved superior performance compared to state-of-art methods. The experimental results revealed that the A-SBiLSTM with attention mechanism and fitness analysis achieved superior performance than other advanced methods for accurate RUL prediction.

State-space modeling and novel entropy-based health indicator for dynamic degradation monitoring of rolling element bearing

This work is dedicated to the establishment of state-space modeling combined with a novel probabilistic entropy-based health indicator (HI), needed to assess the dynamic degradation monitoring and estimation of remaining useful life (RUL) of rolling element bearing. The classical statistical HI such as kurtosis exclusively fails to hold the understanding and steadiness for fault detection under multifaceted noisy situations. It is highly influenced by load and speed because of its sensitiveness towards deterministic vibrations (high probabilistic distribution data). Contemporary, the proposed probabilistic entropy-based HI is less sensitive to high probabilistic distribution data, which makes it capable of using it under different load and speed conditions. The proposed HI is skilled enough to be deployed for initializing the proposed state-space (SS) model, intended to predict futuristic values of HI of time horizon. The continuous updating of the model is done using predicted HI values to determine the futuristic failure time and RUL of bearing. The proposed methodology is deployed to two different data sets: Intelligent Maintenance Systems (IMS) and Xi'an Jiaotong University (XJTU). The experimental result suggests that our entropy-based State Space model is superior in comparison with the existing models General Regression Neural Network (GRNN) and Auto-Regressive Integrated Moving Average (ARIMA) for estimating RUL and carrying out the dynamic degradation monitoring of rolling element bearing.