小波包和小波脊线相结合的解调方法在液压泵故障诊断中的应用  

Method of Signal Demodulation Based on Wavelet Packet Decomposition and Wavelet Ridge Line and Its Application on Hydraulic Pump Fault Diagnosis

作　　者：刘思远[1,2] 胡浩松[1,2] 丁琳琳[1,2] 

机构地区：[1]燕山大学河北省重型机械流体动力传输与控制重点实验室,河北秦皇岛066004 [2]燕山大学先进锻压成形技术与科学教育部重点实验室,河北秦皇岛066004

出　　处：《液压与气动》2015年第4期50-55,共6页Chinese Hydraulics & Pneumatics

基　　金：国家重点基础研究发展计划(973计划)(2014CB046405);河北省自然科学基金(E2013203114)

摘　　要：针对轴向柱塞泵故障振动信号呈现出的非平稳和非线性特点,提出了一种基于小波包能量法与小波脊线法相结合的信号解调方法,将其用于液压泵故障诊断中的信号解调过程。该方法首先对原始振动信号进行功率谱分析,明确故障振动信号反映出的能量集中频带带宽;根据确定的带宽和原始信号分析频率设定小波包分解的层数,采用小波包能量法提取出分解系数对应频带能量最大的特征信息进行信号重构;利用小波脊线法对重构后的频带信号进行解调处理,通过信号的包络解调谱提取故障的特征频率,利用解调后的时频谱对液压泵单柱塞滑靴磨损、斜盘磨损以及中心弹簧故障进行分析。通过实验结果验证,该方法能有效地对液压泵的故障信号进行解调,并能找出反映故障的敏感特征频率。Aimed at the non-stationary and nonlinear characteristic of vibration signals from the faulty axial piston pump, a demodulation approach based on the wavelet packet decomposition and wavelet ridge line is proposed in this paper in the signal demodulation process. The frequency range which energy is concentrated in is found out through the power spectrum of fault vibration signal. Then the number of layers decomposed by the wavelet packet is determined according to the determinate bandwidth and analysis frequency of the original signal. The wavelet packet energy method also is used to ascertain the frequency band containing the maximal energy. Afterwards the corresponding decomposition coefficients are extracted to reconstruct the signal. Next, the reconstructed signal is demodulated by means of wavelet ridge line method. Fault characteristic frequency is effectively extracted from en- velope spectrum to determine the working conditions and the fault tvne. At last , fault signals of single piston slipper wear, swash plate wear and centering spring fail are analyzed. The results show that this method can effectively de- modulate the fault signals and extract sensitive characteristic frequency representing fault status.

关 键 词：故障诊断 小波包分解 小波脊线 信号重构 特征频率 

分 类 号：TH137[机械工程—机械制造及自动化] TH115