高精度硬支承动平衡机通用测量系统的研究与实现

发布时间：2018-03-09 03:08

本文选题：动平衡机测量系统　切入点：不平衡信号提取　出处：《上海大学》2014年博士论文　论文类型：学位论文

【摘要】：不平衡信号提取的精度和效率是影响动平衡机测量系统精度和效率的主要因素，确定不平衡信号和转子校正面上等效不平衡量之间关系的系统标定的准确性也是影响动平衡测量精度的关键因素之一。本文从提高硬支承动平衡机通用测量系统的精度和效率出发，在论述动平衡测量系统原理和误差分析的基础上，分别对近频干扰和转速波动环境下不平衡信号的高效、高精度提取方法以及永久标定法开展了深入研究。主要研究内容和特色贡献包括：（1）根据硬支承平衡机测量原理，给出了通用动平衡测量系统的组成，分析了硬支承平衡机测量系统的几种误差来源，重点讨论了近频干扰和转速波动对动平衡测量精度和效率的影响。（2）针对低速平衡系统的信噪比差、易产生近频干扰导致的不平衡提取精度和效率不高等问题，通过仿真分析了近频干扰时快速傅立叶变换（FFT）法和相关法两种传统不平衡信号提取方法的性能，结果表明这两种方法都需要较长的数据样本才能保证一定的不平衡信号提取精度，且对近频干扰信号的相位、频率等参数变化敏感。为克服传统法的不足，提出一种基于谐波小波和Prony算法的不平衡信号提取方法，并分别进行了仿真和现场实验分析。结果表明，即便有多个近频干扰信号时，该方法只需采用较短数据样本序列便能准确提取出不平衡信号的幅值和相位，且提取精度对干扰信号的相位、频率等参数的变化不敏感，具有较高精度和鲁棒性。（3）对于转速波动的转子系统，振动信号具有明显的非平稳性，如用平稳信号分析法提取不平衡信号会带来较大误差。由此本文提出非平稳转速下两种不平衡信号提取方法：一是基于等相位重采样的不平衡信号提取方法，即根据瞬时频率对等时采样的振动信号进行等相位重采样，可以改善传统快速傅立叶变换（FFT）法的相位提取精度；二是基于经验模态分解（EMD）和最小二乘法（LSA）的不平衡信号提取方法，即根据瞬时频率构造不平衡信号，再从EMD滤波后的振动数据中截取样本数据，由LSA识别出不平衡信号的幅值和相位。仿真和实验结果表明，当转速波动时，两种方法都可以明显改变不平衡信号提取的精度和稳定性，当信噪比较小时，基于EMD和LSA的不平衡信号提取方法的性能更好，适合于工程应用。（4）永久标定法是硬支承动平衡机通用测量系统中常用方法，具有简单、实用等特点。本文详细分析了硬支承平衡机永久标定法的原理误差，采用数字仿真的方法给出了原理误差与转子质量和频比之间的关系。针对传统永久标定法忽略惯性力和阻尼带来的测量误差，提出一种基于Thiele连分式插值法的永久标定改进方法，实现了宽转速范围内的较高的测量精度。（5）研制了具有自主知识产权的高精度动平衡机通用测量系统。硬件系统由模拟信号处理板、数据采集卡和工业单板机组成，软件系统采用WindowsXP环境下的C++Builder编制，界面友好，具有很强的扩展功能。系统的最小可达剩余不平衡量优于0.1gmm/kg，一次不平衡减少率优于95%，能满足大部分旋转机械动平衡试验的要求，具有很强的通用性。
[Abstract]:Don't balance the precision and efficiency of signal extraction are the main factors influencing the dynamic balance machine measurement system accuracy and efficiency, determine the unbalanced relationship between the signal and the accuracy of the calibration system of rotor unbalance on the equivalent positive school is the key factors affecting the measurement accuracy of a dynamic balance. This paper improve the efficiency and accuracy of hard bearing balancing general measurement system based on dynamic balance principle and error analysis of measurement system based on of near frequency interference and speed fluctuation under unbalanced signal, high precision, extraction methods and permanent calibration method is researched. The main research contents and contributions include the characteristics:
(1) according to the measuring principle of hard support balancing machine, the composition of universal dynamic balance measurement system is presented. Several error sources of the measurement system of hard bearing balancing machine are analyzed. The influence of near frequency interference and speed fluctuation on the accuracy and efficiency of dynamic balance measurement is mainly discussed.
(2) poor signal-to-noise ratio for a low speed balancing system, easy to produce near frequency interference unbalance extraction accuracy and efficiency is not high, through the simulation analysis of nearly frequency interference fast Fu Liye transform (FFT) method and the correlation method of two kinds of traditional extraction methods of unbalanced signal, the results show that the data sample can these two methods will require a longer guarantee certain unbalanced signal extraction accuracy, and the phase of near frequency interference signal, frequency and other parameters sensitive. In order to overcome the deficiency of the traditional method, this paper presents an approach to extract unbalance signal and harmonic wavelet based on Prony algorithm, and analyzes the simulation and field the experimental results, even if there are multiple near frequency interference signal, the method only needs to use short data sequence can accurately extract unbalance signal amplitude and phase, and the extraction accuracy of interference signal phase The changes of the bit, frequency and other parameters are not sensitive, and have high accuracy and robustness.
(3) for rotor speed fluctuation, vibration signals are clearly non-stationary, such as non-stationary signal analysis method to extract unbalance signal will bring great errors. This paper puts forward two kinds of non-stationary unbalanced signal extraction methods: one is based on the unbalanced signal extraction method of phase re sampling. According to the sampling of vibration signals of instantaneous frequency equal phase resampling, can improve the traditional fast Fu Liye transform (FFT) method, the phase extraction accuracy; the two is based on empirical mode decomposition (EMD) and least squares (LSA) method to extract unbalance signal, according to the instantaneous frequency of structural unbalance signal, and then from the vibration data of the EMD filtered interception of sample data by LSA identify the amplitude and phase unbalance signal. Simulation and experimental results show that when the speed fluctuation, the two methods can significantly change the unfair The precision and stability of the signal extraction, when the signal to noise is relatively small, the performance of the unbalanced signal extraction method based on EMD and LSA is better. It is suitable for engineering applications.
(4) permanent calibration method is widely used, hard bearing balancing machine universal measurement system has the advantages of simple, practical and so on. This paper analyzes the principle error of hard bearing balancing machine permanent calibration method, using the method of digital simulation is presented and the principle error of rotor mass and frequency ratio between the traditional measurement error. Permanent calibration method ignores inertia and damping caused by the proposed Thiele continuedfraction interpolation method based on improved permanent calibration, the measurement accuracy of a wide speed range high.
(5) developed with independent intellectual property rights of the high precision dynamic balancing machine general measuring system. The hardware system consists of analog signal processing board, data acquisition card and industrial microcomputer, software system using WindowsXP under the environment of C++Builder software, friendly interface, strong expanding function. The minimum achievable residual unbalance system the amount is less than 0.1gmm/kg, an unbalance reduction rate is less than 95%, can satisfy the majority of rotating machinery dynamic balance test, has a strong versatility.

【学位授予单位】：上海大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TP274;TH877

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