【作者】 黄震；

【导师】 刘彬；

【作者基本信息】 燕山大学 ， 光学工程， 2010， 博士

【摘要】 大尺寸测量技术是制造和安装高精度大型机械加工零部件的基础支撑技术之一,长期以来一直是困扰计量工作者的技术难题。本文在详细地分析和比较了现有各种测量原理和技术的前提下,就大尺寸光学测量方法进行了深入系统地研究。在脉冲激光测距原理的基础上,建立了单次多测量方法的数学模型和基于有源光环路结构的串行计数大尺寸测量系统。分析了系统色散引起的激光脉冲展宽,以及被测对象粗糙表面反射引起的脉冲展宽和衰减对大尺寸测量系统性能的限制,研究了解决方案。在有源光环路噪声分析的基础上,建立了大尺寸测量系统等效模型,并进行了仿真研究以优化系统结构。通过理论推导和实验验证相结合的方式分析了环路损耗等参数对系统性能的影响,最终确定了以有源光环路的自脉冲代替外部输入激光脉冲构建大尺寸测量系统,以保证测量精度。本系统在提高测量精度的同时,还保留了脉冲激光测距抗干扰能力强和便携的优势,可以降低大型机械加工零部件制造和安装成本,提高效率,具有广阔的应用前景。主要的研究内容有:首先,研究测量激光脉冲飞行时间新方法——单次多测量的数学模型。把激光脉冲飞行时间测量精度依赖于计数脉冲频率转换为更便于控制的时钟脉冲的相移。这样可以绕过电子瓶颈对时钟频率的限制,提高激光脉冲飞行时间测量精度,满足大尺寸测量对高精度的要求。其次,研究可实现性强的测量系统——串行计数系统。设计以掺铒光纤放大器为核心的有源光环路结构,实现大尺寸测量激光脉冲的循环复制,以确保与单次多测量原理保持一致。在有源光环路噪声分析的基础上建立系统等效模型,并通过该模型的仿真研究优化系统结构。然后,设计实验系统,研究光环路损耗、输入激光脉冲功率和光放大器泵浦功率等参数对大尺寸测量系统性能的影响,确定系统最佳工作条件。并通过实验研究比较外部输入激光脉冲方案和自脉冲方案的系统结构和性能差异,以进一步提高测量精度。最后,分析系统的误差种类和来源,根据系统结构特点运用差分测量算法,将系统测量和自校准、自误差补偿有机地结合在一起,使系统能够动态地误差补偿和校准,保证校准过程更方便;配合事件记录得到的冗余数据,共同补偿由于色散、光纤和逆反射器折射率及环境温度等因素引起的确定性和随机性误差,保证系统测量精度。更多还原

【Abstract】 Large-scale metrology is one of the basic supporting techniques for manufacturing and installing large-scale mechanical parts with high precision, and one technical challenge to metrologists. Deep and systematical research on optical methods of large-scale metrology is performed after analysis and comparison of present measuring principles and technologies. The mathematical model of the new method named multiple-flight-in-single-shot is established, which is based on the principle of pulsed laser ranging. And the serial counting system of large-scale metrology, based on the structure of an active optical loop, is under research. Performance limitations, from pulse broadening caused by dispersions and from pulse broadening and loss caused by rough surface reflections of objects, are analyzed and resolved. The equivalent model of the large-scale metrology system is created by analyzing noises of active optical loops, and simulated in order to optimize systematic structures. Performance influences of optical loop loss and other factors are profoundly analyzed theoretically and experimentally. And self-pulsation replaces the input pulse in order to improve accuracy further. Measurement precision is promoted, and the high noise immunity and portability of pulsed laser ranging are reserved. The producting and installing costs could be decreased and the efficiency increased with great application prospects. The main contents are discribed as follow:First, the new method’s mathematical model of multiple-flight-in-single-shot is established. The clock pulse frequency, which restricts the precision of the time-of-flight measuement, is converted into other physical quantities of the phase shifts. Precision could be promoted further by bypassing the electrical bottleneck of the clock frequency, and meet demand of the large-scale metrology for high accuracy.Second, the serial counting system is designed with high feasibility. Cyclic replication, of a laser pulse for large-scale metrology, is realized by the structure of the active optical loop with the core of an Er-doped fiber amplifier, in order to keep coincidence with the principle. The equivalent model is established by analyzing noises of the active optical loop. And structure optimizations are achieved through the model simulation.Then, experiment system is set up. Performance influences from optical loop loss, input pulse power and pumping power are profoundly analyzed in order to find best conditions for system. Comparison between two system schemes, of the input laser pulse and self-pulsations, is performed through experimental researchs in order to improve precision further.Last, the types and sources of errors are analyzed. Differential measurement algorithm is used according to the structural features, which endows the system with the functions of self-calibration and self errors correction. So, the system could be calibrated by itself easily and correct errors dynamically. Differential algorithm and redundant data obtaining by events recording, jointly correct deterministic and random errors caused by dispersions, refract index of optical fibers and retro-reflector, and surrounding temperature, and so on, to keep best performance.更多还原