基于EMD的转子系统复合故障诊断的实验研究

发布时间：2018-06-19 01:36

本文选题：旋转机械 + 小波降噪　；参考：《内蒙古科技大学》2015年硕士论文

【摘要】：旋转机械作为大多数机械设备的主要组成部分，经常会出现各种各样的故障，而转子不平衡和转子弯曲又是其中经常出现的两种故障。有转轴的机械设备大多数都会存在滚动轴承，而滚动轴承也是常用且容易产生故障的部件。在实际工作中，旋转机械往往会有多种故障同时出现的情况。这种情况更加复杂，越来越受到人们的重视，准确的诊断出这些故障对于设备的正常运行和生产安全有着重要的意义。本文以转子系统为研究对象，主要运用小波降噪理论、EMD理论以及冲击脉冲法对于滚动轴承与转子不平衡的复合故障、滚动轴承与转子弯曲的复合故障进行了诊断，同时对滚动轴承的内圈故障、外圈故障以及滚动体故障进行了诊断。首先，通过在机械综合故障模拟试验台上模拟各种单一故障和复合故障，转速分别设置为1000rpm、1500rpm、2000rpm、2500rpm和3000rpm，提取振动信号。对于提取的原始信号利用小波理论进行降噪处理，降低了噪声的干扰。其次，对降噪后的信号用EMD进行分解，针对EMD存在的端点效应问题，运用了端点镜像延拓的方法进行了改进，，成功的运用到复合故障的诊断中。对于EMD分解出来的包含故障的IMF成份求解功率谱，并与正常状态和单一故障作对比，从而诊断出该系统同时存在两种复合故障。针对滚动轴承的故障，先用冲击脉冲法（SPM）进行初步的诊断，确定了滚动轴承存在故障，但是冲击脉冲法无法确定发生故障的部分，因此利用MATLAB编写程序求频谱。从频谱图中，诊断滚动轴承发生故障部位，并把复合故障的两种故障分离开，并且分别确定每一种故障，从而实现了故障诊断。最后，对内圈故障分别与转子不平衡和转子弯曲复合，然后与只有内圈故障的情况下对比，观察各自曲线趋势，得到高转速下复合另一种故障对原来故障影响明显，低转速下几乎没有影响，而且复合转子不平衡和转子弯曲对于内圈故障的振动幅值影响差距不大，但都是复合转子不平衡的影响更明显；同样对外圈故障和滚动体故障也进行上述的对比，也有相同的结论。
[Abstract]:As the main component of most mechanical equipment, rotating machinery often occurs a variety of faults, and rotor unbalance and rotor bending are two common faults. Rolling bearings are often found in mechanical equipment with rotating shafts, which are also commonly used and prone to malfunction. In practice, rotating machinery often has a variety of failures at the same time. This situation is more and more complex, more and more people pay attention to, accurate diagnosis of these faults for the normal operation of equipment and production safety has an important significance. In this paper, the rotor system is taken as the research object. The EMD theory of wavelet noise reduction and the impulse pulse method are mainly used to diagnose the complex faults of the imbalance between the rolling bearing and the rotor, and the composite fault of the rolling bearing and the rotor bending. At the same time, the inner ring fault, outer ring fault and rolling body fault of rolling bearing are diagnosed. First of all, by simulating each kind of single fault and compound fault on the mechanical comprehensive fault simulation test bench, the rotational speed is set to 1000rpmO1500rpmC2000 RPM 2500rpm and 3000rpm respectively, and the vibration signal is extracted. For the original signal, wavelet theory is used to reduce the noise. Secondly, the de-noised signal is decomposed by EMD, and the method of endpoint image continuation is improved to solve the problem of end-point effect in EMD, which is successfully applied to the diagnosis of complex faults. The power spectrum of the IMF component which is decomposed by EMD is solved and compared with the normal state and the single fault so that the system has two kinds of complex faults simultaneously. In view of the fault of rolling bearing, the initial diagnosis is carried out by impulse pulse method (SPM), and the fault of rolling bearing is determined, but the part of fault can not be determined by impulse pulse method, so we use MATLAB to program the frequency spectrum. From the spectrum diagram, the fault location of rolling bearing is diagnosed, and the two kinds of fault of compound fault are separated, and each kind of fault is determined separately, thus the fault diagnosis is realized. Finally, the inner ring fault is combined with rotor unbalance and rotor bending respectively, and then compared with only inner ring fault, the trend of each curve is observed, and the influence of complex other fault at high speed on the original fault is obvious. At low speed, there is little effect on the vibration amplitude of the inner ring fault, but the effect of the complex rotor unbalance is more obvious than that of the complex rotor unbalance and the rotor bending has little effect on the vibration amplitude of the inner ring fault. The same comparison is made between the outer ring fault and the rolling body fault, and the same conclusion is reached.
【学位授予单位】：内蒙古科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH165.3

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