A Milling Chatter Identification Method Based on Variational Mode Decomposition and Energy Entropy

Abstract

The invention discloses a milling flutter recognition method based on variation modal decomposition and energy entropy, and belongs to the technical field of machine tool machining flutter recognition. The milling flutter recognition method comprises the following steps of S1, establishing a VMD mathematical model; S2, establishing a mathematical model of the energy entropy; S3, conducting three sets of milling machining experiments representing three cutting states, including stable cutting, a weak flutter and a severe flutter, and obtaining three sets of milling force signals through a dynamometer; S4, conducting FFT analysis on the three sets of milling force signals, and proving that the three sets of milling force signals represent the states of stable cutting, the weak flutter and the severe flutter respectively; S5, determining the number K of optimal modals of VMD decomposition and a penalty factor alpha through a VMD parameter automatic selection method based on a kurtosis value; S6, solving instantaneous frequencies of multiple IMF, and determining a milling flutter characteristic frequency band; S7, adopting a hammering experiment to obtain the modal of a knife; S8, extracting a flutter characteristic vector of each IMF based on the energy entropy. According to the milling flutter recognition method based on the variation modal decomposition and the energy entropy, the VDM decomposition effect is improved, and automatic flutter recognition is achieved.

Description

technical field [0001] The invention belongs to the technical field of machine tool machining chatter recognition, and relates to a milling chatter recognition method based on variational mode decomposition and energy entropy. Background technique [0002] In order to improve the material removal rate and reduce the cutting force, high-speed milling is widely used in the aerospace industry. Machine tool chatter originates from the self-excitation mechanism in chip formation. A certain mode of the tool-workpiece system is initially excited by the cutting force, which generates chatter at a frequency close to but not equal to the main structure frequency of the machining system. Chatter reduces surface quality, productivity, and causes tool wear. For the chatter problem of the machining process system, many scholars have proposed methods such as chatter stability prediction, identification, and suppression, but for machine tool operators, it is difficult to implement the meth...

AI Technical Summary

Problems solved by technology

However, at present, the energy entropy of the entire signal is usually selected as the flutter feature, and the flutter frequency band and flutter feature vector are not really extracted.

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