共查询到19条相似文献,搜索用时 118 毫秒
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循环统计量方法在滚动轴承故障诊断中的应用 总被引:7,自引:0,他引:7
为了处理滚动轴承故障振动信号中的调制现象,利用循环统计理论,分析了二阶统计量循环自相关函数和循环谱密度的特性。基于故障调幅信号模型推导出循环自相关函数的解调原理,指出调幅信号各成分在循环谱密度中的分布频段,提出在循环频率域中提取调幅信号的调制源的方法。该原理和方法通过仿真信号进行验证,应用于滚动轴承的内、外圈及滚动体的故障诊断,有效地提取出故障特征频率。 相似文献
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滚动轴承微弱故障信号往往包含在二阶循环平稳信号中,但容易受到噪声干扰。对循环平稳信号进行基于短时傅里叶变换的循环周期谱分析可以提高周期故障的识别能力,但其结果受到窗函数大小的影响且对于微弱故障的诊断效果不佳,提出最优小波尺度循环谱进行滚动轴承的早期故障诊断。首先利用连续小波变换对信号进行处理获得小波系数;接着采用相关峭度方法选择最优的分析尺度;然后沿着时间轴对该尺度范围内的小波系数进行循环谱分析;最后对最优尺度下的循环谱平均进行特征提取。与循环周期谱的分析结果进行对比,验证了该方法在早期故障特征提取方面的有效性。 相似文献
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基于循环平稳分析理论,对滚动轴承部分故障振动信号提出了一种新的模型——二重调幅信号模型。在对二重调幅信号理论进行研究的基础上,采用循环频率扫描分析二重调幅信号的调制源及其载波的分布规律。对仿真信号应用循环自相关函数分析,验证此方法的正确性。并应用该方法对滚动轴承故障进行分析,实践证明此方法能够有效地分离出滚动轴承对应的故障特征频率。 相似文献
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根据滚动轴承振动信号的性质,提出了一种基于小波包系数、峭度最大值原则及包络谱分析的滚动轴承故障自动诊断方法.首先,用小波包将信号分解到不同的频段上,再对不同频段的小波包系数计算其峭度值;然后,根据峭度值最大原则,自动确定由轴承缺陷所引起的共振频率所在的频带;最后,对该频带的小波包系数进行包络谱分析,以确定故障频率.此方法能够提高滚动轴承故障诊断的可靠性和便捷性. 相似文献
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为了对旋转机械中滚动轴承的运行状态进行故障监测和诊断,提出了一种基于EMD和Hilbert包络谱的滚动轴承故障诊断新方法.通过在滚动轴承实验台上提取振动信号,用EMD对数据进行分解得振动信号的固有模态函数分量(IMF分量),然后对IMF作Hilbert包络并进行谱分析.结果表明,该方法能够准确地识别和诊断出滚动轴承的运行状态和故障类型,非常适合滚动轴承故障精确诊断,具有很高的工程实用价值. 相似文献
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《机械传动》2016,(6):144-148
为了对旋转机械中滚动轴承的运行状态进行故障监测和诊断,提出了一种基于边带相关算法和Hilbert包络谱的滚动轴承故障诊断新方法。通过对滚动轴承产生振动的模型进行分析,可以将振动信号看成为多个调制信号的叠加,而边带相关算法可以在频谱图基础上找出调制性最强的频率区间,然后进行带通滤波得到此频率区间内的时域信号,最后对其进行Hilbert包络并进行谱分析,最终能得到调制信号中调制频率的大小。利用滚动轴承实验取得的振动信号进行分析验证,可以在滚动轴承具有外圈、内圈、滚动体缺陷的情况下的振动信号找出调制频率,有效地提取故障特征。结果表明该方法能够准确地识别和诊断出滚动轴承的故障部位和类型。 相似文献
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针对低转速齿轮箱齿轮故障特征频率低、故障特征频率易被背景噪声淹没,使其难以准确提取的问题,提出了基于参数优化的变分模态分解(parameter optimization variational mode decomposition,简称POVMD)和循环自相关函数(cyclic autocorrelation function,简称CAF)结合的故障诊断方法。首先,通过POVMD对原始信号进行分解,选用余弦相似度度量选取敏感的本征模态函数(intrinsic mode function,简称IMF);其次,计算其循环自相关函数谱,获得包含调制特征的循环自相关函数谱切片;最后,使用Teager能量算子(Teager energy operator,简称TEO)算法对切片解调,提取故障特征频率。同时将本方法与相关方法进行了对比分析,特征频率提取效果更加显著,仿真信号和实验数据分析验证了该方法的有效性和可靠性。 相似文献
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讨论循环平稳信号的循环自相关函数特性,指出循环自相关函数不为零的循环频率对应着信号的周期成分。基于调幅和调频信号模型推导出循环域解调方法,通过扫描循环频率域使调制源(故障)信息解调在循环域的低频段和高频段。利用高频段无调制源交叉项的特点,对滚动轴承故障进行诊断,有效地提取出外圈、内圈和滚动体的故障特征。 相似文献
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Note: multiplexed multiple-tau auto- and cross-correlators on a single field programmable gate array
Mocsár G Kreith B Buchholz J Krieger JW Langowski J Vámosi G 《The Review of scientific instruments》2012,83(4):046101
We introduce a new multiple-tau hardware correlator design for computing fluorescence correlation functions (CFs) in real time. Use of hardware resources is minimized by scheduling the computation of different segments of the CFs on a single correlator block. Simultaneous calculation of two multiple-tau autocorrelation (ACFs) and two cross-correlation functions (CCFs) is implemented in LabVIEW on a National Instruments field programmable gate array (FPGA) card with a minimal sampling time of 400 ns. Raw data are stored with a time resolution of 50 ns. The design can be easily adapted to other FPGA cards and extended to more inputs. 相似文献
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Network data-transfer times in distributed simulation environments can be reduced by performing data analysis at the remote source, if the analytical technique does not require the entire set of data at once. This novel multi-tau autocorrelation algorithm allows time-domain data records to be processed in discrete, distributed segments and combined at a later point in time. The new approach agrees with autocorrelation results performed by concatenating the discrete segments before correlation, but it operates with significantly shortened processing times. The multi-tau algorithm also benefits from reduced memory requirements since it does not require access to the entire data record at once, and from improved scalability since the multi-tau algorithm has order O(N), while fast Fourier transform autocorrelation algorithms have order O(N log N). This distributed algorithm has particular utility in simulations of fluorescence correlation spectroscopy or photon correlation spectroscopy. 相似文献
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An FPGA-based acoustic time-delay meter with the post-detection correlation processing of pseudo-noise signals is proposed. The measurement method is based on the real-time computation of the mutual correlation function between the reference signal that follows the modulation law and the received signal. The experimental results obtained using a prototype of the developed system are presented. The results validated the viability of the developed software and hardware solutions as applied to acoustic-, radio-, and hydroacoustic-location systems. 相似文献
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通过信号仿真,研究了二阶循环平稳分析的解调性能,并总结出循环自相关与谱相关切片函数的一般规律,分析了故障电动机轴承振动信号的循环平稳特性。试验中,模拟并采集工况中带有强噪声的内圈故障电动机轴承的振动信号,提出用小波消噪与特殊频率处谱相关切片结合的分析方法,进行特征提取,分析过程中发现,这种方法能有效实现轴承快速诊断,避免三维函数分析信息冗余、计算量庞大的缺点,同时也排除了瞬时转速与额定转速偏差引起的干扰。 相似文献
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A.C Rao 《Mechanism and Machine Theory》1983,18(5):335-338
Exact solutions are not usually available for nonlinear vibration problems. Approximate solutions, graphical and analytical, reported so far are tedious. This paper deals with a simple method replacing the nonlinear term by an equivalent linear term obtained using the concept of force or energy correlation. Autocorrelation of a function ensures complete equality and similarity while correlation between two functions can be taken as a measure of similarity between them. Autocorrelation of the strain energy of the nonlinear spring and the correlation between the strain energies of the actual and equivalent linear springs can be expressed as functions of displacement. By squaring and summing of the difference between the autocorrelation for one quarter cycle an objective function is formulated, minimisation of which gives the optimum value of the equivalent spring constant. The concept can be extended to problems with nonlinear damping. Enery correlation gives accurate results. Three example problems are included to cover hard and soft springs and coulomb friction. 相似文献
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谱相关特性在机械信号特征提取中的应用研究 总被引:1,自引:0,他引:1
将机械振动信号视为循环平稳信号,用循环统计方法进行处理。探讨了循环平稳信号的遍历性及其统计量的时间平均估计方法,着重研究了二阶循环统计量的谱相关特性,指出利用谱相关特性的频率选择性和噪声抑制性可以消除信号中的加性或乘性随机噪声以及非同频成分的干扰,有效地提取出信号特征频率。通过对滚动轴承、注浆泵等旋转和往复机械的振动信号分析表明,谱相关特性在机械信号特征提取方面具有很好的应用价值。 相似文献