基于近场声全息的车辆噪声源识别

发布时间：2018-11-12 21:16

【摘要】：为解决近场声全息(NAH)声场测量时,测量噪声降低近场声全息重建精度、影响声场重建的实现的问题,本文通过对基于近场声全息噪声源识别方法的理论研究,提出一种基于NAH的噪声源识别方法,旨在准确识别和定位车辆噪声源。本文的主要内容主要有以下几个部分:第一部分首先说明论文研究的目的和意义,接着在基础理论部分对波动方程、赫姆霍兹-基尔霍夫积分定理的声辐射理论、瑞利积分等公式对连续NAH及NAH离散化公式进行推导;最后对NAH进行仿真分析,探讨全息测量孔径、重建距离、采样间隔等不同重建参数对声场重建结果的影响。第二部分论文基于传递函数法,提出一种基于传递函数估计的NAH技术。首先引入一种合理的传递函数估计,结合参考传声器信号来求解全息面复声压,再根据声场重建公式进行NAH声场重建。对该方法与传统NAH的噪声源识别效果进行试验对比来验证该方法的可行性及有效性,为后文该方法在车辆噪声源识别中的应用作了铺垫。第三部分对熵及奇异值分解的基本理论和性质进行研究,采用双测量面方式进行声场的测量,提出基于奇异值能量熵的双测量面NAH声源识别。并给出具体仿真方案设计流程,最后在存在测量噪声的情况下,对基于奇异值能量熵的双测量面NAH声源识别进行方法的仿真验证。第四部分对基于传递函数估计及奇异值能量熵的双测量面NAH试验系统进行设计,以某拖拉机前端为研究对象,进行双测量面近场声场测量试验,利用前面所述的声源识别算法进行噪声源识别的试验研究及分析,给出试验结果、结论;对比分析本文所用方法与传统方法实验结果,进一步对本文所用方法的优越性和可靠性进行验证。
[Abstract]:In order to solve the problem that the measurement noise reduces the accuracy of the near-field acoustic holography reconstruction and affects the realization of the acoustic field reconstruction in the near field acoustic holography (NAH) acoustic field measurement, this paper studies the theory of the recognition method based on the near-field acoustic holographic noise source. A noise source recognition method based on NAH is proposed to accurately identify and locate vehicle noise sources. The main contents of this paper are as follows: in the first part, the purpose and significance of the research are explained, and then the sound radiation theory of the wave equation, Hem Holtzhoff integral theorem, is discussed in the basic theory. The continuous NAH and NAH discretization formulas are deduced by Rayleigh integral and other formulas. Finally, the effects of different reconstruction parameters, such as holographic measurement aperture, reconstruction distance and sampling interval, on the results of acoustic field reconstruction are discussed by simulation and analysis of NAH. In the second part, based on transfer function method, a NAH technique based on transfer function estimation is proposed. First, a reasonable transfer function estimation is introduced to solve the complex sound pressure of holographic plane with reference microphone signal, and then the NAH sound field reconstruction is carried out according to the sound field reconstruction formula. The comparison between the method and the traditional NAH method is carried out to verify the feasibility and effectiveness of the method, which lays the groundwork for the application of this method in vehicle noise source identification. In the third part, the basic theory and properties of entropy and singular value decomposition are studied, the sound field is measured by double measurement plane, and the NAH acoustic source recognition based on singular value energy entropy is proposed. The design flow of the simulation scheme is given. Finally, the method of NAH acoustic source recognition based on singular value energy entropy is verified in the presence of measurement noise. In the fourth part, a dual measurement plane NAH test system based on transfer function estimation and singular value energy entropy is designed. Taking the front end of a tractor as a research object, the near field acoustic field measurement test of two measuring surfaces is carried out. The experimental research and analysis of the noise source recognition are carried out by using the sound source recognition algorithm mentioned above, and the experimental results and conclusions are given. The advantages and reliability of the methods used in this paper are verified by comparing the experimental results of the methods used in this paper with those of the traditional methods.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U467.493

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