基于EEMD和CWT的挖掘机座椅振动分析

Vibration analysis of excavator seat based on EEMD and CWT

针对某型液压挖掘机座椅振动加速度信号,应用集总经验模式分解(ensemble empirical mode decomposition,EEM D)方法进行处理,提出以能量贡献率与相关性分析相结合的方法,实现本征模态函数(intrinsic mode function,IM F)中冗余项和伪信号的剔除;并应用连续小波变换(continuous w avelet transform,CWT)对各有效IM F分量进行时频分析,实现振源特征提取和定位。试验分析表明:影响驾乘舒适性的分量主要来源于发动机的发火激励和2阶转动激励,同时缸内气体压力循环作用产生的发动机切向、径向激励力也是一个重要的来源。该方法可有效地实现座椅振源信号的分解、筛选及定位,对于研究挖掘机振动舒适性具有一定的应用价值。

The measured seat vibration responses of an excavator were firstly processed by ensemble empirical mode de-composition （EEMD）.In order to eliminate meaningless and spurious components from the obtained intrinsic mode functions （IMF）,a new method combining energy contribution ratio and correlation analysis was proposed.Then the selected “interesting”IMFs with actual physical interpretations were processed by continuous wavelet transform （CWT）.Based on time-frequency characteristics of IMFs,the vibration signals corresponding to different excitation sources could be located and identified.The experimental results showed that combustion forces and second-order rota-tion forces of diesel engine contributed mainly to seat vibration,meanwhile,the tangential and radial forces of diesel en-gine caused by circulated gas pressure in cylinder also made contributions.The proposed method could be employed ef-fectively in decomposing,selecting and locating the seat vibration source signals,which was greatly helpful to further study of riding comfort.