【作者】 杨健；

【导师】 金湘亮；

【作者基本信息】 湖南师范大学 ， 电子与通信工程（专业学位）， 2021， 硕士

【摘要】 在工业生产、军事和医疗等领域都需要对温度参量进行实时的在线监测,尤其是军事和医疗领域对温度检测的精度提出了更高的要求。但是传统有源温度传感器(热电偶)在上述恶劣领域中容易受其他军用设备的电信号和外界环境中强电磁场的干扰,其测温精度和稳定性无法保证。因此,对外界绝缘的高精度荧光型光纤温度传感器的研究显得十分必要。本文首先对比分析了三种光纤荧光测温系统的原理和优势,最终选定荧光寿命型光纤温度传感器为研究重点。然后对系统硬件电路、软件与数据处理算法等关键技术展开深入研究与设计,实现了荧光型光纤温度传感器的原理样机。本论文主要工作内容如下:1.为保证荧光信号的完整性和一致性,本论文对发光二极管(Light-Emitting Diode,简称LED)的驱动电路和荧光信号的放大电路两个模块进行深入研究与设计。LED驱动电路基于脉宽调制技术和负反馈技术,实现光源的周期性调制和荧光信号强度的间接调控。该负反馈方案能够减少荧光强度的波动对系统测温精度的影响。为保证放大电路工作在线性区,通过负反馈技术对放大电路的静态工作电压进行矫正。该负反馈方案能够避免荧光信号产生截止失真或者饱和失真。2.荧光寿命计算的准确性取决于采样间隔和数据处理算法。本论文采用模拟数字转换器(Analog-to-Digital Converter,简称ADC)的定时器触发功能,同时配置直接存储器访问(Direct Memory Access,简称DMA)进行采样数据的传输,从而保证采样间隔的固定。在数据处理算法中,本论文实现了一种新型的加权线性最小二乘拟合算法。该算法无需设置初始猜测值。通过实验验证,该算法相比于优化前的加权线性最小二乘拟合算法的精度提高了约65.5%,并且数据处理算法的响应时间减少了约36.5%。3.基于荧光寿命与温度的相关性原理,本论文对系统的电路、软件和数据处理算法进行设计,实现了荧光型光纤温度传感器的原理样机。测试数据表明荧光寿命与温度具有良好的线性度。在25℃-100℃的温度范围内,该系统的最佳测温精度约为±0.1℃。更多还原

【Abstract】 In industrial production,military,medical and other fields,real-time online monitoring of temperature parameters is needed.In particular,the fields of military and medical have higher requirements for the accuracy of temperature detection.However,traditional active temperature sensors(thermocouples)are susceptible to interference from the electrical signals of other military equipment and strong electromagnetic fields in the external environment in the above-mentioned harsh areas,and the temperature measurement accuracy and stability cannot be guaranteed.Therefore,it is necessary to study the high-precision fluorescent optical fiber temperature sensor with complete insulation.Firstly,this paper compares and analyzes the principle and advantages of three optical fiber fluorescence temperature measurement systems,and finally the fluorescence lifetime optical fiber temperature sensor is selected as the research focus.Then,the key technologies such as hardware circuit,software and data processing algorithm of the system are deeply studied and designed,and the principle prototype of fluorescent optical fiber temperature sensor is realized.The main contents of this paper are as follows:1.In order to ensure the integrity and consistency of the fluorescence signal,the driving circuit of the light-emitting diode(LED)and the amplification circuit of the fluorescence signal are studied and designed in this paper.The LED drive circuit is based on pulse width modulation and negative feedback,which realizes the periodic modulation of the light source and the indirect regulation of the intensity of the fluorescent signal.The negative feedback scheme can reduce the influence of the fluctuation of the fluorescence intensity on the temperature measurement accuracy of the system.In order to ensure that the amplifier circuit works in the linear region,the static working voltage of the amplifier circuit is corrected by negative feedback technology.The negative feedback scheme can avoid cut-off distortion or saturation distortion of the fluorescent signal.2.The calculation accuracy of fluorescence lifetime depends on sampling interval and data processing algorithm.In this paper,a timer is used to trigger Analog-to-Digital Converter(ADC)sampling,and Direct Memory Access(DMA)is configured to transmit the sampling data,so that the sampling interval is equal.In the data processing algorithm,a new weighted linear least squares fitting algorithm is implemented in this paper.The algorithm does not need to set the initial guess value.Experimental results show that the accuracy of the algorithm is improved by about 65.5%compared with the weighted linear least squares fitting algorithm without improvement,and the response time of the data processing algorithm is reduced by about 36.5%.3.Based on the principle of correlation between fluorescence lifetime and temperature,the circuit,software and data processing algorithm of the system are designed,and the principle prototype of fluorescence fiber temperature sensor is realized.The test data shows that the fluorescence lifetime has a good linearity with temperature.In the temperature range of25℃ to 100℃,the best temperature measurement accuracy of the system is about ±0.1℃.更多还原