【作者】 宋丽娜；

【导师】 姜万录；

【作者基本信息】 燕山大学 ， 机械电子工程， 2008， 硕士

【摘要】 干式真空泵的正常运转是真空系统稳定工作的保证,液压泵是液压系统的“心脏”,所以对干式真空泵、液压泵等旋转机械进行状态检测和故障诊断技术的研究是非常必要的。论文以旋转机械故障特征提取技术为研究对象,提出了基于复解析小波的小波包络解调新方法并应用到干式真空泵、液压泵等故障诊断中。该研究不仅具有重要的理论意义,而且对其他旋转机械的故障诊断具有推广应用价值。概述了旋转机械振动监测技术相关理论,对振动信号采集过程中的测点位置以及传感器类型选择进行说明,并着重对振动信号的幅值域、时域以及频域分析方法进行了深入的研究。系统地研究了小波分析理论在振动信号分析领域的应用,与传统的基于FFT的信号分析方法相比有其独到的优势,能够满足大多数旋转机械振动信号分析的要求。采用传统的小波包络分析对振动信号进行分析处理时,通常需要对振动信号进行小波分解滤波,再进行Hilbert变换才能得到包络信号,运算过程复杂,运算量大,从而限制了其在实时诊断系统中的应用。基于Morlet复解析小波变换的正交性,提出基于小波簇的带通滤波和包络解调新方法。通过合理的选择小波参数,用多个单Morlet小波组成的小波簇可构成具有零相移、平顶通带及快速衰减过渡带特性的带通滤波器,用于提取振动信号的高频谐振成分。这种方法将信号滤波和Hilbert变换两个步骤合二为一,简化了运算步骤,缩短了运算时间,提高了故障诊断的实时性。将该方法用于液压泵、干式真空泵等泵类旋转机械故障振动信号分析处理之中,实验结果表明它能有效地提取故障特征频率,诊断结果验证了该方法的有效性。更多还原

【Abstract】 The running status of dry vacuum pump influences the stability of the whole vacuum system and the hydraulic pump is the“heart”of the hydraulic system. So the condition monitoring and fault diagnosis of the rotary machine such as dry vavuum pump and hydraulic pump is crucial.This paper advances the extractive technique as subject investigated,A Morlet-like wavelet cluster-based method for band-pass filtering and envelope demodulation is described and it is applied for fault diagnosis relating to the rotary machine such as dry vavuum pump and hydraulic pump.It is not only important for theoretical study,but also has popularization to other rotary machine.This paper summarizes vibration monitoring technique relating to rotary machine,then illustrates how to select the testing position and the vibrational sensor.Especially makes profound institute to amplitude domain and time domain and frequency domain analysis method.Systematically researches the basic ideas of Wavelet Transfomation theories when it is used in the vibrational signals.It is verified that wavelet analysis method is unique compared to FFT. The method is suitable for most rotary machine.When using classical wavelet envelope demodulation method, generally first makes wavelet decomposition for filtering to the vibration signals ,then Hilbert Transformation,Last we can get the envelope signal .In this way the process of calculation is complex. Here a Morlet-like wavelet cluster-based method for band-pass filtering and envelope demodulation is described. Via appropriate choice of wavelet parameters, a wavelet cluster combined with multi-Morlet-like wavelet can be used as a band-pass filter with zero phase shift, flat topped pass-band and rapid attenuation in the transition band. It can be used to extract high frequency natural vibration components. This new method is applied for fault diagnosis relating to the rotary machine such as dry vavuum pump and hydraulic pump. It is shown that the fault characteristic frequencies can be extracted effectively. The efficacy of the method is demonstrated in experimental studies.更多还原