【作者】 魏玉果；

【导师】 汤宝平；

【作者基本信息】 重庆大学 ， 机械电子工程， 2007， 硕士

【摘要】 阶次分析技术是旋转机械振动信号分析和故障诊断的重要技术之一,其特点是充分利用转速信息。旋转机械在升、降速阶段产生的振动信号是一基频随时间不断变化的非平稳信号,基于FFT的传统谱分析方法无法有效的提取和分析该阶段的特征信息,而阶次分析技术的出现很好的解决了这一问题。本课题主要围绕这一全新的旋转机械振动信号分析技术而展开。转速计算是阶次分析中的关键技术之一,本文提出并实现了基于一阶数字微分、单脉冲分段插值的转速计算方法。该方法通过对一阶数字微分计算得到的初始转速进行分段变点数插值,获得每个采样时刻的转速,建立起了转速值同振动幅值的对应关系,为后续的阶次分析打下了基础。阶次跟踪技术一直是阶次分析的研究重点,本文在比较和分析当前国内外各种阶次跟踪方法优缺点的基础上,结合求解的初始转速和圆周运动学方程,提出并实现了基于圆周运动学方程的自适应计算阶次跟踪技术。该技术根据转速变化的大小,自适应的选择不同的方法进行阶次重采样。在转速变化缓慢时,采用一次线性插值方法;在转速变化大时,采用匀角加速运动方程方法;在转速变化剧烈时,采用三次样条插值的方法来进行阶次跟踪。该方法在保证计算精度要求的同时,提高了计算的执行效率。对阶次重采样后的振动信号作FFT即可得到阶次谱。为了得到阶次谱中感兴趣阶次的时域波形,文章还实现了基于Gabor时频滤波技术的阶次分量提取。时频谱阵是分析非平稳振动信号的常用方法,但对于旋转机械而言,时频谱阵很难揭示出峰值同转速之间的关系。本文在分析短时傅立叶变换实现原理的基础上,结合计算得到的转速曲线,提出并实现了基于转速时刻加窗的傅立叶变换(FT)算法,为旋转机械转速谱阵计算提供了理论依据。在深入研究现有阶次分析技术的基础上,根据提出的新观点和新方法,研制和开发了面向旋转机械的阶次分析系统。该系统从运行界面、结果显示到各项算法功能的实现均是利用VC++从底层编程开发完成。现场测试实验分析结果表明本文所提出的阶次分析方法是正确的、有效的,所研发的阶次分析系统功能全面,具有明显的实用价值,为推动阶次分析技术在旋转机械非平稳振动中的应用打下了坚实的基础。更多还原

【Abstract】 Order analysis is one of the most important techniques of rotating machinery involving vibration signal processing and fault diagnosis. Its characteristic is fully using the information of rotating speed. The vibration signal of rotating machinery generated during the acceleration or deceleration phase is the non-stationary signal, which the fundamental frequency changes with the time. Traditional spectral analysis methods based on FFT can not effectively extract and analyze the characteristic information of this phase. However the emergence of order analysis can resolve the problem well. The technique will be studied in this paper.Rotating speed computation is one of the key technologies of order analysis. Computing method of rotating speed based on one digital differential, single pulse subsection interpolation is proposed and implemented in this paper. This method firstly calculates the initial speed with one order digital differential, then through subsection interpolation, gets the rotating speed of every sampling moment, establishs the relationship of speed and vibration amplitude, and lays the foundation for the follow-up order analysis.Order tracking technology is one of the most important areas of order analysis. Based on the comparison and analysis the advantages and disadvantages of current order tracking methods, and combining the initial speed and circular motion equation, the adaptive calculation order tracking technology based on the circular motion equation is proposed and implemented in the paper. This technology according to the change of rotating speed, adaptive selects different method to calculate order tracking. When the change of speed is slow, we adopt the linear interpolation method to calculate order tracking; when the change of speed is large, we use constant angular acceleration equation to calculate order tracking; when the change of speed is dramatic, we use cubic spline interpolation method to calculate order tracking. The method improves the operating efficiency while guaranteeing the requirements of accuracy. Then order spectrum can be obtained after the FFT of order re-sampled vibration signal. In order to obtaining the time-domain waveform of interested order from order spectrum, order component extraction. based on Gabor time-frequency filtering technology is implemented.Time-frequency analysis is one of the commonly used methods for analysis the non-stationary vibration signals. But for rotating machinery, time-frequency analysis is difficult to reveal the relation between amplitude and rotating speed. With deep research on the principle of Short-Time Fourier Transformation (STFT), combining the rotating speed calculated by subsection interpolation, the algorithm of rotating speed moment adding window Fourier Transform is proposed and implemented in the paper, which provides the theoretical basis for computing rotating speed spectral map of rotating machinery.After through research on the existing order analysis techniques, with new ideas, new methods and new approaches proposed in this paper, the order analyzer system for rotating machinery is developed. The system that includes interface, results display and all kinds of arithmetic function is developed through VC6.0. Experimental test results show that the method which is researched and proposed in the paper is correct and effective, and the value of the developed system is obvious. It lays firm basement for promoting extensive use of order analysis in rotating machinery non-stationary vibration.更多还原