液压系统故障特征提取方法研究

FAULT FEATURE EXTRACTION OF HYDRAULIC SYSTEM

针对液压系统故障特征不清楚、诊断特别困难的难题,提出利用EEMD分解与相关性分析相结合的液压系统故障特征提取方法。首先用EEMD分解液压故障信号得到一组IMF分量,从中筛选出与故障信号自身相关系数大的IMF分量作为一组故障的候选IMF分量集;再在故障信号的IMF分量中筛选出与正常信号相关系数小的IMF分量,作为另一组故障的候选IMF分量集;两组候选IMF分量集的交集确定原故障信号的主要故障特征IMF分量,作自功率谱分析即可得到所提取IMF分量包含主要故障特征频率,并通过所提取IMF分量与正常信号的互功率谱验证特征提取的正确性。用该方法准确提取出液压实验台泄漏故障特征IMF分量以及故障特征频率。

Aiming at the problem that the fault feature of hydraulic system is not clear and difficult to diagnosis, a feature extraction method of faults is proposed in this paper which combines EEMD with correlation analysis. First, a group of IMF components of hydraulic fault signal was obtained by EEMD. Screened the IMF components strongly correlated with fault signal as a group of faults＇ candidate IMF component set. Then screened the IMF components little correlated with normal signal as another group of faults＇ candidate IMF component set. The intersection of two candidate IMF component sets were the main fault features of the original fault signals of IMF components. The main fault characteristic frequency of fault signal could be got by the spectrum analysis. Then use the cross-power spectrum of fault IMF component and normal signal to prove the validity of the feature extraction. The fault feature IMF components and fault frequency of hydraulic system leakage fault of the hydraulic simulator are extracted in this paper.