基于散布熵和余弦欧氏距离的滚动轴承性能退化评估方法

Rolling bearing performance degradation assessment method based on dispersion entropy and cosine Euclidean distance

针对传统特征指标评估轴承性能退化状态时可靠性、敏感性低的问题,提出一种基于散布熵和余弦欧氏距离的滚动轴承性能退化评估方法。首先,将待测滚动轴承振动信号分为健康数据和测试数据,分别对其进行集成经验模态分解(ensemble empirical mode decomposition, EEMD),得到若干本征模态分量(intrinsic mode function, IMF),计算各IMF分量与原信号的相关系数,并根据相关系数准则选择IMF分量重构信号;然后,计算重构信号的散布熵,通过结合欧氏距离和余弦距离得到健康数据和测试数据散布熵之间的余弦欧氏距离作为退化指标;最后,利用切比雪夫不等式计算余弦欧氏距离健康阈值,评估轴承性能退化状态。实验结果表明,利用散布熵之间的余弦欧氏距离可以有效、及时地判断轴承性能退化状态,并且与其他指标相比,其敏感性、鲁棒性更高,能够更好地刻画滚动轴承性能退化趋势,为滚动轴承性能退化评估提供新的解决方法。

Aiming at the problems of low reliability and sensitivity when evaluating the degradation of bearing performance with traditional characteristic indicators, a method for evaluating the degradation of rolling bearing performance based on dispersion entropy and cosine Euclidean distance is proposed. First, the vibration signal of the rolling bearing to be tested is divided into health data and test data, decomposed by EEMD respectively to obtain several Intrinsic Mode Functions(IMF). Calculatethe correlation coefficient between each IMF component and the original signal, and the IMF components are selected according to the correlation coefficient criterion to reconstruct signal. Then, the dispersion entropy of the reconstructed signal is calculated, and the Euclidean distance and the cosine distance are combined to obtain the degradation index cosine Euclidean distance between the health data and the test data dispersion entropy. Finally, the Chebyshev inequality is used to calculate the cosine Euclidean distance health threshold to evaluate the degradation of the bearing performance. The experimental result shows that the cosine Euclidean distance between dispersion entropy can effectively and timely judge the degradation state of the bearing performance, and compared with other indexes, its sensitivity and robustness are higher, which can better describe the degradation trend of the rolling bearing performance, and provide a new solution for the evaluation of the rolling bearing performance degradation.