【作者】 曹汇敏；

【导师】 陈幼平； 周祖德；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2007， 博士

【摘要】 光纤传感器以其抗电磁干扰、耐恶劣环境、远程测量、体积小等先天优势从众多传感器中脱颖而出,成为现代传感技术的主攻方向。作为光纤传感领域中的重要一族,光强反射式光纤传感器更具有结构紧凑、成本低廉、性能可靠、设计灵活等独特优点。本文以非接触式高精度微位移和氢气测量为突破口,在微小型光纤传感器的理论建模、光强补偿技术、微弱信号处理技术以及传感器样机研制和试验等方面进行了系统深入的研究。首先,根据位移和氢气的不同传感机理,建立了反射式光纤位移传感器和微镜式光纤氢气传感器的理论模型,仿真研究了传感器的理论特性,分析了各相关参量对传感器特性的影响规律,实验验证了理论模型的有效性。为改善光纤传感器在微位移和氢气测量中的精度、稳定性、线性范围、探头尺寸等,在分析了影响传感器性能的各种因素和典型光强补偿方法的基础上,提出了一种组合式光纤束位移传感器探头和一种耦合器分光型光纤氢气传感器探头,给出了基于理论模型的探头优化设计方法,实验验证了探头的补偿效果。为进一步提高光纤传感器的测量精度和线性范围,本文还研究了光强补偿算法。将神经网络应用于光纤传感器的光强补偿,提出了一种基于径向基函数神经网络的光强补偿方法。针对研发的新型探头,进行了神经网络补偿实验,结果表明,该方法同时实现了光纤传感器的高精度光强补偿和非线性校正。微弱光电信号处理是光纤传感器的重要组成部分。研究了相关检测理论和锁定放大技术,开发了光纤传感器的模拟信号处理系统和嵌入式数字信号处理系统,实现了性能稳定的光源调制驱动和接收信号的实时高精度解调。数字信号处理系统还具有可置换的光纤探头接口和网络接口,并实现了自诊断、自校正等智能功能。最后,基于上述研究结果,研制了光纤位移传感器和光纤氢气传感器样机,给出了相关制作工艺,进行了传感器的试验研究。试验结果表明,这两种样机均达到了设计要求的性能指标。更多还原

【Abstract】 Due to the advantages of immunity to electromagnetic interference, resistance to harsh environment, remote measurement, and small size, an optical fiber sensor outstands from others and becomes the main direction of advanced sensing technologies. As important one of optical fiber sensors, the intensity reflecting optical fiber sensor has more unique advantages of compact structure, low cost, good reliability and flexibility.In respect of non-contact high-precision micro-displacement measurement and hydrogen gas detection, several key problems of micro optical fiber sensors are studied systematically in this dissertation, which include theoretical modeling, intensity compensation, weak signal processing, as well as developing and testing of prototypes.Firstly, according to different sensing mechanisms in displacement and hydrogen measurement, the theoretical models of reflective optical fiber displacement sensor and micro-mirror optical fiber hydrogen sensor are built, respectively. Their theoretical characteristics are simulated, the influence rules of related parameters on which are analyzed and the validity of the built models are verified by experiment.After analyzing various factors influencing on performance of optical fiber sensors and typical intensity compensation methods, in order to improve their precision, stability, linear range and probe size, a combined optical fiber bundle displacement sensor probe and an optical fiber coupler hydrogen sensor probe are proposed. Their optimizing design methods based on theoretical models are presented. To illustrate compensation performance of the proposed probes, experiments are carried out.An intensity compensation algorithm is studied to increase the precision and linear range of optical fiber sensors further. Applying neural network to intensity compensation of optical fiber sensors, a method based on radial basis function network is proposed. Experiments using the proposed method show that intensity compensation and nonlinearity correction of optical fiber sensors are fulfilled simultaneously.Weak photoelectric signal processing is an important part of optical fiber sensor. Theories about correlation detection and lock-in amplifier are studied. An analog signal processing system and an embedded digital signal processing system for optical fiber sensors are developed, which modulate and drive the light source stably and realtime demodulate the receiving signals. The digital signal processing system has a replaceable optical fiber probe interface and a network interface, and some intelligent functions as self-diagnostics and self-correction.At last, based on the research above, the prototypes of an optical fiber displacement sensor and an optical fiber hydrogen sensor are developed. Corresponding fabricating technics are presented. Testing results show that they satisfied design requirements.更多还原