• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2022, Vol. 58 ›› Issue (3): 140-148.doi: 10.3901/JME.2022.03.140

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Investigation on Chatter Monitoring of Composite Milling Edge Based on the Selection of Sensitive Frequency Band of Wavelet Packet

ZHANG Lei, ZHENG Kan, SUN Lianjun, SUN Hongwei, XUE Feng, WANG Tao   

  1. School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094
  • Received:2021-02-19 Revised:2021-06-23 Online:2022-02-05 Published:2022-03-19

Abstract: A novel energy entropy chatter monitoring method based on the selection of sensitive frequency band of wavelet packet is proposed to solve the problem of the initial chatter frequency submerged in the milling of large aviation skin composite materials. Firstly, the frequency elimination algorithm (FEA) is performed to remove the spindle rotation frequency, tooth passing frequency and their harmonics on the signals collected by the edge milling. Secondly, wavelet packet transform (WPD) is applied to decompose the filtered signal into a set of frequency bands and the frequency band distribution characteristics of WPD are analyzed. Then, sensitive frequency bands containing rich chatter information are selected as the research object based on the frequency band correlation coefficient ρ and energy ratio fluctuation variance σ2 and energy entropy is extracted as the chatter monitoring feature. Meanwhile, PauTa criterion is used for determining the chatter monitoring threshold of the system. Finally, the simulation signal and experimental signal are employed to verify the effectiveness of the algorithm. The results showed that the energy entropy resolution ratio of the signal is increased by 202% after the FEA and sensitive frequency band selection, compared with the original signal, and the system chatter condition can be detected 0.5s earlier.

Key words: wavelet packet decomposition, sensitive frequency band, chatter, energy entropy, frequency elimination algorithm

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