基于EMD-Wigner-Ville的内燃机振动时频分析  

I.C.engine vibration time-frequency analysis based on EMD-Wigner-Ville

作　　者：蔡艳平[1] 李艾华[1] 王涛[1] 姚良[1] 许平[1] 

机构地区：[1]第二炮兵工程学院五系,陕西西安710025

出　　处：《振动工程学报》2010年第4期430-437,共8页Journal of Vibration Engineering

基　　金：博士后科学基金资助项目(20070411116);第二炮兵工程学院创新性基础研究基金资助项目(XY2009JJB33)

摘　　要：在分析多分量信号时,WVD交叉项的出现极大干扰了对信号的时频分析,针对现有WVD交叉项抑制方法存在聚集性与交叉项成分抑制相互矛盾的问题,提出了一种基于经验模态分解(EMD)的WVD交叉项抑制方法。该方法首先利用EMD分解方法,将信号分解成相互独立的一系列具有不同特征时间尺度的固有模态函数(IMF),然后运用相关系数法对经验模式分解伪分量进行剔除,再对每个IMF进行Wigner-Ville分析,最后把各个IMF的Wigner-Ville分析结果线性叠加重构原始信号的时频分布。仿真实验结果表明,该方法既能有效抑制时频分布的交叉项,又保证了Wigner-Ville分布的时频聚集性。将EMD-Wigner-Ville应用在内燃机振动时频分析中,两个实例有效地揭示出了内燃机振动信号的特征信息,克服了HHT时频分布、Wigner-Ville时频分布在分析内燃机振动信号时的缺陷,是一种有效的时频分析方法。As to multi-signals, the figure of time-frequency distribution becomes difficult to understand due to cross-terms in the Wigner-Ville distribution （WVD）. At present time, cross-terms suppression of time-frequency analysis is one of the top interests in signal processing, and more and more research had been put on this topic, but the present research on cross-terms suppression exist conflicting problem that these methods couldn＇t suppress the cross-terms while holding high time-frequency resolution. A novel method of cross-terms suppression in the WVD based on Empirical Mode Decomposition （EMD） was pro- posed to solve the above problem. Firstly, multi-component signals were decomposed into intrinsic mode functions （IMFs） which were single component signal by EMD; Secondly, the relation coefficient values of IMFS and original signal were calculated to judge and delete the EMD false components; Thirdly, these Wigner-Ville distributions of true component of IMFs were computed; Finally, WVDs of each single component signal were added linearly to reconstruct the WVD of original sig- nal. Test on synthetic data shows the effectiveness of the proposed method, which can suppress the cross-terms while holding high time-frequency resolution. The proposed method was applied in I.C. Engine vibration signals time-frequency analysis, and the EMD-Wigner-Ville time-frequency distributions of two examples reflect I.C. engine vibration signal feature informa- tion effectively. Its merit of proposed method shows EMD-Wigner-Ville is an effective time-frequency distribution to analyze I.C. Engine vibration signals by comparing with Hilbert-Huang transform and Wigner-Ville distribution.

关 键 词：内燃机 时频分析 WIGNER-VILLE分布 交叉项 经验模态分解 

分 类 号：TK418[动力工程及工程热物理—动力机械及工程] TN911.6[电子电信—通信与信息系统]