本文選題：振動(dòng)信號(hào) + 特征提取　； 參考：《合肥工業(yè)大學(xué)》2014年碩士論文

【摘要】：在數(shù)控機(jī)床電主軸測(cè)試系統(tǒng)中,需要從采集的振動(dòng)信號(hào)中提取動(dòng)不平衡量對(duì)不平衡的電主軸進(jìn)行質(zhì)量補(bǔ)償。通過(guò)測(cè)振傳感器采集得到的動(dòng)不平衡振動(dòng)信號(hào)往往受到噪聲嚴(yán)重的污染,特別是當(dāng)不平衡量很小時(shí),振動(dòng)信號(hào)的信噪比差,會(huì)導(dǎo)致動(dòng)平衡的測(cè)試精度及穩(wěn)定性降低。因此針對(duì)微弱周期振動(dòng)信號(hào)進(jìn)行消噪處理是從強(qiáng)噪聲干擾的振動(dòng)信號(hào)中提取特征信號(hào)的有效手段。本文分析了由轉(zhuǎn)子不平衡引起的振動(dòng)信號(hào)的特征,構(gòu)造了振動(dòng)信號(hào)的數(shù)學(xué)模型。文中研究了第二代小波變換和第二代小波包的頻率混疊問(wèn)題,詳細(xì)闡述了無(wú)頻率混疊現(xiàn)象的自適應(yīng)冗余第二代小波的構(gòu)造方法。針對(duì)該方法中存在的傳統(tǒng)閾值函數(shù)造成小波系數(shù)不連續(xù)或恒定偏差的問(wèn)題,引入雙變量改進(jìn)閾值函數(shù),提出了一種改進(jìn)的基于自適應(yīng)冗余第二代小波的振動(dòng)信號(hào)消噪方法,并結(jié)合互相關(guān)分析對(duì)仿真信號(hào)進(jìn)行消噪,提取動(dòng)不平衡信號(hào)特征值,驗(yàn)證了雙變量改進(jìn)閾值函數(shù)給消噪效果帶來(lái)的改進(jìn)。針對(duì)第二代小波包存在的頻率混疊問(wèn)題,提出了改進(jìn)的第二代小波包算法：置零小波包分解中近似系數(shù)不滿足采樣定理的頻率成分和細(xì)節(jié)系數(shù)中混入的相鄰子帶的頻率成分同時(shí)移頻細(xì)節(jié)系數(shù)中剩下的頻率成分,并恢復(fù)移頻小波包重構(gòu)過(guò)程中的細(xì)節(jié)系數(shù)。通過(guò)仿真實(shí)驗(yàn)對(duì)比分析,驗(yàn)證了改進(jìn)的第二代小波包算法能很好的保留原信號(hào)的特征并且有效的去除噪聲,有助于普羅尼算法更加準(zhǔn)確的提取動(dòng)不平衡信號(hào)的頻率和相位。
[Abstract]:In the electrical spindle test system of numerical control machine tools, the quality compensation of the unbalanced electric spindle should be extracted from the vibration signal from the vibration signal. The dynamic unbalance vibration signal obtained by the vibration sensor is often polluted seriously by the noise, especially when the unequal measurement is very small, the signal to noise ratio of the vibration signal is poor and will guide the vibration signal. The precision and stability of the dynamic balance are reduced. Therefore, the noise elimination for the weak periodic vibration signal is an effective means to extract the characteristic signals from the vibration signals with strong noise interference. This paper analyzes the characteristics of the vibration signals caused by the rotor unbalance, and constructs a mathematical model of the vibration signal. In this paper, the second generation of the vibration signals is studied. The frequency aliasing problem of the wavelet transform and the second Dai Xiaobo packet is discussed in detail. The construction method of adaptive redundancy second Dai Xiaobo is described in detail. In view of the problem that the traditional threshold function in this method causes the discontinuous or constant deviation of the wavelet coefficients, the two variable quantity is introduced to improve the threshold function, and an improved basis is proposed. In the adaptive redundancy second Dai Xiaobo vibration signal denoising method, combining the cross correlation analysis to denoise the simulation signal and extract the characteristic value of the dynamic unbalanced signal, the improvement of the bivariate improved threshold function is verified. The improved second Dai Xiaobo is proposed for the frequency aliasing problem in the second Dai Xiaobo packet. Packet algorithm: the approximate coefficients in the zero wavelet packet decomposition are not satisfied with the frequency components of the frequency components of the adjacent subbands mixed with the sampling theorem and the frequency components of the frequency shift detail coefficient at the same time, and the detail coefficients of the frequency shift wavelet packet reconstruction are restored. The improved second is verified by the comparison and analysis of the imitation true experiment. The Dai Xiaobo packet algorithm can preserve the characteristics of the original signal well and effectively remove the noise. It can help the prop algorithm to extract the frequency and phase of the dynamic unbalanced signal more accurately.

【學(xué)位授予單位】：合肥工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN911.7;TG659

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