【作者】 阳光辉；

【导师】 李绪友；

【作者基本信息】 哈尔滨工程大学 ， 导航、制导与控制， 2010， 硕士

【摘要】 在爆轰冲击波测试、高速碰撞、火箭推进等工程应用领域中,光纤测速作为一种时间和空间分辨率较高的非接触测量手段被广泛应用。与传统激光测速相比,全光纤测速系统以其可靠性好、调试方便、利于多点测速等优点成为测速领域的研究重点。在干涉测量中,对系统进行模型分析以及如何提高系统输出信号质量和有效地细分条纹一直是研究重点,而且,系统的后端数据处理也非常关键。本文针对几个关键部分进行研究,主要内容如下:首先,阐述了国内外测速系统的发展,对发展过程中典型的测速系统进行了原理分析和描述,给出了传统测速与光纤测速的区别;基于光学多普勒效应和混频原理,对全光纤多普勒测速系统的原理进行了分析,推导了差拍多普勒系统的测速公式,分析了条纹采集数目对测速误差的影响。其次,对全光纤测速系统的光路系统进行光学建模,建立了系统各个光学器件的琼斯矩阵,为测速系统的光路研究提供了理论研究基础。基于理论化的光学模型,推导了正弦振动下的系统理论输出,并分析推导了光器件误差对系统的影响。再次,研究了测速系统中关键器件光源和耦合器对系统测速的影响。先对系统中光源参数对系统性能的影响进行了分析,推导了谱宽影响干涉输出的条纹对比度公式,给出了光源在不同测试条件下的实验测试曲线。而后分析了耦合器分光比对系统信号调制度的影响,推导了基于麦克斯韦方程的模耦合理论并测试了利用熔融拉锥制法制作的耦合器,给出了系统实验曲线。最后,针对差拍系统输出的信号特点,给出了信号的变化规律及系统条纹常数的修正及检测方法,利用皮秒激光器进行了实验。针对系统的高速测速时的条纹丢失现象,分析了几种系统条纹丢失的补偿方法。针对低速测量场合,提出了一种三角波调制的条纹细分的方法,对调制过程进行了详细分析,并给出了基于FPGA的细分电路的原理设计和FPGA片内时序控制模块部分的仿真曲线。更多还原

【Abstract】 As a high time and space resolution and non-contact measurement method laser velocity measurement system is used widely in the project field of explosive detonation shockwave test, weaponry design, high velocity impact, rocket propulsion. Traditional laser velocity measurement system is difficult to progress further because of defect such as complex structure, debugging difficulty, and so on. Compared with traditional system, all fiber velocity measurement system becomes the trend owns to its advantage of compact structure, high stability, debugging difficulty. The performance of fiber source and coupler are very important to the system, also the data processing could not be neglect if want to improve the system. The content of this dissertation is as follows:Firstly, it describes the history of velocity measurement system home and abroad, the principle of system, and the difference between traditional system and all fiber system. All fiber system is detailed based on Doppler Effect and frequency mixing theory, the velocity expression is derived, and the effect of fringe number on velocity is also described.Secondly, the demand of use of fiber source in different application is analyzed based on the parameters of fiber source. The effect of parameters such as spectrum width, mean wavelength and the stability of output power of fiber source on system performance are also analyzed. The curves of output signal of the system and its fringe constant with the variation of spectrum width are given. And then the experimental testing curves are derived in different conditions.Additionally, it conducts the study of influence of coupler on velocity measurement, the mode coupling theory based on Maxwell equations is described, and the effect of coupling ratio on output interfere fringe contrast is analyzed. Coupler is affected by other external factors in the course of fabrication; it is adjusted to fabricated using fused biconical taper. The experimental testing curves of fabricated coupler are given. Finally, the correction factor of fringe constant and measurement method are conducted as to dispersion and impact characteristic of optical devices. It analyzes the phenomenon of fringe loss in detail and gives the ways to compensate it based on the characteristic of output signal of the system. The improved system is described as to the defects of single-ended detect and the corresponding data processing is given. In order to enhance the performance one method for fringe subdivision and the electrical circuit design are given.更多还原