Diversity entropy-based Bayesian deep learning method for uncertainty quantification of remaining useful life prediction in rolling bearings

Remaining useful life (RUL) prediction of rolling bearings plays a critical role in reducing unplanned downtime and improving machine productivity. The existing prediction methods primarily provide point estimates of RUL without quantifying uncertainty. However, uncertainty quantification of RUL is crucial to conduct reliable risk analysis and make maintenance decision, which can significantly decrease the maintenance costs. To solve the uncertainty quantification problem and improve prediction accuracy at the same time, a novel diversity entropy-based Bayesian deep learning (DE-BDL) method is proposed. First, start degradation time (SDT) of bearings is adaptively determined using diversity entropy, which can extract early degradation information. Then, multi-scale diversity entropy (MDE) is developed to extract dynamic characteristics over multiple scales. Third, the obtained features using MDE are fed into the BDL model for degradation tracking and prediction. By doing this, the proposed DE-BDL method has merits in subsequent decision making, which can not only provide point estimation but also offer uncertainty quantification with epistemic uncertainty and aleatoric uncertainty. The superiority of the proposed method is validated using run-to-failure data. The experimental results and comparison with state-of-art prediction methods have demonstrated that the proposed DE-BDL method is promising for RUL of rolling bearings.