Department of Automation, Xi'an Research Institute of High-Tech, Xi'an 710025, China.
The Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, Xi'an Jiaotong University, Xi'an 710049, China.
Sensors (Basel). 2019 Mar 26;19(6):1472. doi: 10.3390/s19061472.
Owing to operating condition changing, physical mutation, and sudden shocks, degradation trajectories usually exhibit multi-phase features, and the abrupt jump often appears at the changing time, which makes the traditional methods of lifetime estimation unavailable. In this paper, we mainly focus on how to estimate the lifetime of the multi-phase degradation process with abrupt jumps at the change points under the concept of the first passage time (FPT). Firstly, a multi-phase degradation model with jumps based on the Wiener process is formulated to describe the multi-phase degradation pattern. Then, we attain the lifetime's closed-form expression for the two-phase model with fixed jump relying on the distribution of the degradation state at the change point. Furthermore, we continue to investigate the lifetime estimation of the degradation process with random effect caused by unit-to-unit variability and the multi-phase degradation process. We extend the results of the two-phase case with fixed parameters to these two cases. For better implementation, a model identification method with off-line and on-line parts based on Expectation Maximization (EM) algorithm and Bayesian rule is proposed. Finally, a numerical case study and a practical example of gyro are provided for illustration.
由于运行条件的变化、物理突变和突发冲击，退化轨迹通常表现出多相特征，并且在变化时刻经常出现突然跳跃，这使得传统的寿命估计方法不再适用。在本文中，我们主要关注如何在第一通过时间（FPT）的概念下，估计具有突变的多相退化过程的寿命。首先，基于 Wiener 过程，我们构建了一个具有跳跃的多相退化模型，以描述多相退化模式。然后，我们基于变化点处的退化状态分布，获得了两阶段固定跳跃模型的寿命闭式表达式。此外，我们继续研究了由单元间变异性引起的随机效应和多相退化过程的寿命估计。我们将具有固定参数的两阶段情况的结果扩展到这两种情况。为了更好地实施，我们提出了一种基于期望最大化（EM）算法和贝叶斯规则的离线和在线部分的模型识别方法。最后，提供了一个数值案例研究和一个陀螺仪的实际例子来说明。
