摩擦振动时频图像特征提取

Feature extraction of frictional vibration based on time-frequency image

针对摩擦振动特征难以有效提取的问题,提出利用连续小波变换(CWT)时频谱图像和图像处理技术提取摩擦振动特征参数的方法。运用CWT变换绘制6S50MC船用柴油机缸套-活塞环试样摩擦振动信号的时频谱图,再用图像分割技术提取振动特征体及相应的特征参数,探讨特征参数与不同润滑剂润滑条件下缸套-活塞环摩擦振动特性的内在联系。结果表明,随着摩擦磨损过程的进行,摩擦振动信号特征参数出现规律性变化;不同润滑工况下的特征参数呈现出明显的差异,反映了摩擦磨损的状态。振动特征体特征参数能定量刻画摩擦振动信号的特征。

A method to extract features of frictional vibration signals was developed, using continuous wavelet transformation （CWT） time-frequency image （TFI） and image-processing to analyze vibration signals, since frictional vibration signals contained rich information about interface＇s fault state and friction wear state. TFIs were generated with CWT theory from vibration signals produced by cylinder and piston ring samples sampled from a 6S50MC marine diesel engine under two different lubrication states. And characteristic parameters obtained with image segmentation of TFIs were analyzed in order to establish the intrinsic relationship between characteristic parameters and friction wear status. The results showed that characteristic parameters have regular variations with conduct of friction process, and characteristic parameters under different lubrication conditions have significant differences; the CWT TFI characteristic parameters of vibration signals can be used to quantitatively describe friction vibration signal characteristic.