基于VMD和FFT的变切深侧铣颤振特征提取方法

Chatter Feature Extraction Method in Variable Cutting Depth Flank Milling Based on VMD and FFT

针对铣削过程中颤振频带不明显的问题,采用变分模态分解(VMD)和快速傅里叶变换(FFT)相结合的方法来提取颤振频带,为进一步提取颤振特征值奠定基础.为获得包含颤振频率的频带,采用变切深侧铣薄壁件实验获取铣削力信号.提出结合FFT频谱来选择VMD中模态个数的方法,并采用此方法对仿真信号和实验信号进行颤振频带提取,结果表明VMD和FFT相结合的方法能有效提取铣削颤振频带.

A chatter frequency band extracting method combining the variational mode decomposition（ VMD） and fast Fourier transform（ FFT） was proposed for extracting the obscure chatter frequency band in milling process,making good basis of further extracting the chatter feature value. To obtain the frequency band including chatter frequency,the variable cutting depth flank milling experiment was carried out and the forces were measured in the experiment. A method of choosing the number of modes in the VMD by combining the FFT spectrum was proposed. The simulation signal and experiment signal were extracted by the above method. The results show that the method of combining the VMD and FFT can effectively extract the chatter frequency bands in milling,which offers a new method to extract the chatter feature.