An adaptive approach for recovering overlapping echoes in oil film thickness measurement by ultrasound
Abstract
Purpose
For oil film thickness measurement using ultrasonic spring model, obtaining the isolated reflection from the oil film layer is the key point. While for oil film thickness measurement in thrust bearings with thin liner, the reflection from the substrate-Babbitt interface will overlap with the reflection from the oil film layer. This overlapping will render the ultrasonic spring model invalid. To obtain the isolated reflected signal from the oil film layer accurately, an adaptive method was developed to recover the overlapping echoes.
Design/methodology/approach
A genetic-algorithm-based support matching pursuit (GA-based SMP) was developed to provide the optimal echo number and initial parameters guesses automatically and efficiently. Then, the traditional expectation maximization (EM) model was used to fine tune the accurate results.
Findings
The developed method was tested using both simulated echoes and the overlapping echoes encountered in the ultrasonic oil film thickness measurement of thrust bearings. The results demonstrated that the developed method performed well on recovering overlapping echoes adaptively.
Originality/value
The work shows an adaptive method to recover the ultrasonic overlapping echoes. When used in ultrasonic oil film thickness measurement, it can help extend the application of traditional ultrasonic spring model to objects with four or more layers.
Keywords
Acknowledgements
This work was funded by the National Science Foundation of China under grant No. 51705140 and 51675403.
Citation
Zhang, K., Wu, T., Duan, Z., Meng, Q. and Meng, Q. (2017), "An adaptive approach for recovering overlapping echoes in oil film thickness measurement by ultrasound", Industrial Lubrication and Tribology, Vol. 69 No. 5, pp. 788-797. https://doi.org/10.1108/ILT-01-2016-0011
Publisher
:Emerald Publishing Limited
Copyright © 2017, Emerald Publishing Limited