【作者】 姚欣；

【导师】 贺顺忠；

【作者基本信息】 天津大学 ， 光学工程， 2004， 硕士

【摘要】 随着现代工程技术的飞跃发展，特别是航空、航天、机械制造等技术的发展，需要对振动进行高精度测量。尤其是在地球物理勘探中，地震勘探已成为一种最有效、应用最广的勘探方法，广泛用于石油矿藏、煤炭、地热、工程地质、水文地质等的勘探。因此对振动信号的采集和处理、系统辩识、振动和噪声控制等方面的研究变得尤为重要。通过对多种振动测量方法的比较，考虑到激光多普勒效应具有精度高、动态响应快、测量范围大、非接触性测量、抗电磁干扰、对横向振动干扰不敏感等优点，因此本论文选取激光多普勒方法进行振动检测。本论文是国家自然科学基金项目“激光多普勒效应检测地震波的方法和理论研究”研究工作的一部分，考虑到本课题应用的范围，作者主要研究振动频率为2Hz～10Hz范围内的多普勒振动检测技术。主要完成了以下工作：完成多普勒效应测振技术的理论分析研究，设计了差动式激光多普勒光路，采用声光调制器，提高信号的信噪比，使光路的抗干扰能力增强。根据散斑理论，分析了光学结构参数与多普勒信号强度的关系。根据高斯光束理论，针对振动检测的特点，优化了激光多普勒差动光路各项参数，使之具有更高的分辨力和信噪比。研究用锁相放大电路来接收微弱信号，采用NI的数据采集卡进行数据的实时采集。完成了整个系统的调试、数据的记录，并对实验数据进行分析。最采用软件编程的方法得到振动幅度和频率参数。更多还原

【Abstract】 With the rapid development of modern engineering and technology, especially in the area of aviation, spaceflight and machine produce, it’s necessary to make high accuracy vibration measurement. Especially, in the domain of physical geography probe, seism probe has become the most effective and widely used method, which can be used in probing petroleum mineral resources, coal, terrestrial heat, engineering geology and hydrological geology. Therefore, it’s important to acquire and process vibration signals, differentiate and analyze the system, control the vibration and noise. After comparing many vibration detecting methods, considering that the Laser Doppler method has many advantages such as high accuracy, rapid dynamic response, large measuring range, non-contact, resisting electron-magnetic interference, avoiding landscape orientation interference, it is selected to detect vibration in this paper.The works of this paper is one part of the project “research on method and theory of Laser Doppler effect detecting seism wave”. Based on the applied domain of the project, the measurement of signal with vibration frequency range from 2Hz to 10Hz has been studied. The following results are achived:1. Theory of the measurement of vibration using Laser Doppler effect are researched and differential Laser Doppler optical system are designed. Especially, acousto-optic modulator is used in this system, which can improve the signals’ SNR and anti-jamming ability of the optical system.2. According to speckle principle, Relation between intensities of laser Doppler signals and structure parameters of optical system is analysed. Based on Gauss beam theory and characteristic of vibration detecting, the parameters of the optical system are optimized, which has improved the system’s resolution and SNR.3. Lock-in amplifier is researched to detect weak signals, and NI’s DAQ card are used to acquire data. The adjustment of the whole system, acquisition of data and analysis of experiment data are completed. In the end, the software method is applied to get amplitude and frequency parameters of vibration.更多还原