A Modulation Signal Bispectrum Enhanced Squared Envelope for the Detection and Diagnosis of Compound Epicyclic Gear Faults

Yuandong Xu, Guojin Feng, Xiaoli Tang*, Shixi Yang, Fengshou Gu, Andrew D. Ball

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Epicyclic gearboxes are prevalent in a variety of important engineering systems such as automotive, aerospace, wind turbines, civil equipment and industrial robots owing to the merits of compact structure and high power density. To ensure the productivities of such important systems, condition monitoring techniques are being actively studied to resolve the challenge of varying transmission paths and multiple modulations in vibration signals acquired from ring gear housing. This paper proposes a new Modulation Signal Bispectrum (MSB) Enhanced Squared Envelope method to analyse the vibration signals acquired by a special On-Rotor Sensing (ORS) transducer that is mounted on the shaft of an epicyclic gearbox. A vibration signal model of ORS measurements from epicyclic gearboxes is presented to show the multiple modulation influences. Moreover, inevitable noise influences are also investigated on the conventional squared envelope and the state-of-the-art spectral correlation analysis. On this base, MSB is introduced to suppress these influences for accurately extracting equally spaced harmonics in the squared envelope and is then integrated to isolate fault signatures, allowing effective fault detection and diagnosis of epicyclic gearboxes, which lead to novel contributions of an MSB Enhanced Squared Envelope (MSB-ESE) approach. An experimental study of compound epicyclic gear faults was conducted to demonstrate the superior performance of MSB-ESE along with the special ORS technique in detecting and diagnosing the compound faults on sun and planet gears.
Original languageEnglish
Pages (from-to)562-580
JournalStructural Health Monitoring
Issue number1
Early online date21 May 2022
Publication statusPublished - Jan 2023

Bibliographical note

Copyright © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage).


  • Epicyclic gearbox
  • MSB
  • On-Rotor Sensing
  • fault diagnosis
  • squared envelope


Dive into the research topics of 'A Modulation Signal Bispectrum Enhanced Squared Envelope for the Detection and Diagnosis of Compound Epicyclic Gear Faults'. Together they form a unique fingerprint.

Cite this