【作者】 王冬生；

【导师】 王玉田；

【作者基本信息】 燕山大学 ， 仪器科学与技术， 2013， 博士

【摘要】 流量测量在当今工业生产中有着重要的作用，基于光纤系统的流量测量方法已成为其研究的主要方向。当光在光纤中传输时，光的特性如强度、相位、频率等会受到被测量的调制，利用适当的光检测方法可以把调制量转换成电信号。光纤光栅传感器是一种能测量多种参数的传感器，其中心波长漂移量可用于检测流量，具有结构简单、测量精确、量程宽等诸多优点，正逐渐成为流量测量的主要方式之一。光纤布拉格光栅(FBG)传感器以其优异的抗电磁干扰、抗腐蚀、灵敏度高、小巧等特点，被广泛应用于工程监测。论文将光纤光栅传感理论与流量测量相结合，设计了一种新型的流量测量装置。通过对光纤光栅传感器原理，流量传感器原理分析和研究，设计了一套比较完备的光纤光栅流量传感系统，其设计包括光源选择、光电探测器设计、解调装置、信号分离滤波电路、前置放大电路、信号处理电路。在分析光纤布拉格光栅传感原理及信号解调原理的基础上研究设计了一种圆形靶结合粘贴光纤布拉格光栅(FBG)悬臂梁式流量检测装置；研究了传感光栅中心反射波长的变化量与参考光栅中心反射波长变化量的关系式；建立了基于圆形靶流量测量系统的数学模型；提出了基于步进电机调控的等强度悬臂梁光纤布拉格光栅传感信号解调方案；步进电机将电脉冲信号转变为角位移或线位移，在非超载的情况下，电机的转速、停止的位置只取决于脉冲信号的频率和脉冲数，而不受负载变化的影响，并编写了步进电机及单片机的运行程序；该系统具有结构简单，精度较高，成本低等特点；提出了小波变换用于信号的处理、多尺度平滑去噪的思想以及线性模板与多尺度平滑去噪相结合的方法，用于流量信号的消噪，效果明显；设计了一种基于悬臂梁调谐和匹配光栅解调技术的光纤布拉格光栅传感信号解调方法；设计了基于匹配FBG可调滤波检测法的分布式测量系统，大大改善了系统的使用成本、复杂度及信噪比，并根据以上原理设计了系统的各个部分；匹配光纤布拉格光栅可调滤波检测法可以按照自身要求，在需要测量的点装配传感光栅，而只需要制作与其中心反射波长等性质相同的匹配参考光栅，形成测量阵列，匹配参考光栅的波长漂移就可以反映传感光栅的变化；通过对几种常见的流量测量方法进行比较实验测试，由实验数据误差分析可以得出相关结论，验证该设计方案的可行性和精度。更多还原

【Abstract】 Flow measurement plays an important role in modern industrial production. Flowmeasurement methods based on optical fiber system have become the main direction ofthe research. Optical properties such as intensity, phase, and frequency and so on arecontrolled by the measurement when the light transmits in the optical fiber, andappropriate optical detecting methods can convert it into electrical signals. Fiber gratingsensors can measure many parameters, such as flow measurement which develops on thechange of center wavelength, and it has many advantages such as simple structure,accurate measurement, wide measuring range and many other advantages, which isgradually becoming the main mode of flow measurement. Fiber Bragg Grating(FBG)sensor is widely used in engineering monitoring of optical fiber sensing with its excellentresistance to electromagnetic interference, corrosion resistance, high sensitivity, compactand other characteristics.In this paper, we combine the principle of FBG sensor with flow measurementprinciple, and design a kind of new flow measuring device. We design a set of relativelycomplete fiber grating flow sensing system based on the principle of fiber grating sensorand flow sensor’s analysis and research, including light selection, photoelectric detector,demodulation device, signal filtering circuit, preamplifier circuit, and signal processingcircuit.On the basis of analyzing and researching the principle and demodulation techniquefor FBG, a flow measuring device of the circular target binding Fiber Bragg Grating withthe cantilever is designed. The relation between the wavelength shift of sensing FBG andthe wavelength shift of reference FBG is studied and the mathematical model based on acircular target flow measurement system is established.Stepping motor transforms the electricity pulse signal into angle-displacement orline-displacement, in the non-overload situation, the electrical machinery’s rotationalspeed and the stopping position is only decided by the pulse signal’s frequency and thepulse number, and is not influenced by the variation of load. Then it has the preparation of the running program of the stepping motor and single-chip microcomputer. This systemhas the characteristics of simply structure, high precision and low cost. The denoisingmethod of wavelet transform for signal processing, multiscale smoothing and thecombination of the linear template and multiscale smoothing denoising have obviouseffect on flow signal denoising.A scheme of demodulation technique for FBG based on the cantilever controlled bythe stepping motor is proposed, and the demodulation technique based on a pair ofmatching FBG is designed. Distributed measurement system with matching FBG filteringhas greatly improved the cost, complexity and signal-to-noise ratio of the system. Everypart of the system is designed based on the above. Matching FBG filtering detectingmethod can install sensing FBG on the measuring points according to their ownrequirements, and we only need to make the matching reference FBG with the same centerreflective wavelength to it. From the measurement array, wavelength change of matchingreference FBG can reflect the sensing FBG. Several common methods of flowmeasurement are compared by experimental tests, while, experimental data error analysiscan be concluded to verify the feasibility and precision of the design.更多还原