發(fā)布時(shí)間：2018-03-03 12:52

  本文選題：F-P濾波器　切入點(diǎn)：光纖光柵　出處：《南昌航空大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：光纖光柵傳感器較傳統(tǒng)的電學(xué)傳感器,具有抗電磁干擾能力強(qiáng)、耐腐蝕、精度高、結(jié)構(gòu)簡單且價(jià)格低廉等優(yōu)點(diǎn),在石油化工,航空航天,建筑結(jié)構(gòu)等領(lǐng)域具有廣泛應(yīng)用。光纖光柵傳感技術(shù)的關(guān)鍵是解調(diào)系統(tǒng),開發(fā)設(shè)計(jì)一套低成本、便攜式的解調(diào)系統(tǒng)對于拓展光纖光柵傳感技術(shù)的應(yīng)用范圍具有重要意義。本文首先從光纖光柵傳感器的理論研究出發(fā),在詳細(xì)分析比較了常見的五種光纖光柵解調(diào)方式的基礎(chǔ)上,選擇可調(diào)諧光纖法布里-珀羅(FFP)濾波器作為本系統(tǒng)的解調(diào)方法,并設(shè)計(jì)解調(diào)系統(tǒng)的總體方案。根據(jù)光纖光柵解調(diào)系統(tǒng)的總體設(shè)計(jì)方案,完成了光纖光柵解調(diào)系統(tǒng)的軟硬件開發(fā),具體內(nèi)容如下:在系統(tǒng)硬件設(shè)計(jì)上,選擇STM32F4芯片處理核心,設(shè)計(jì)并實(shí)現(xiàn)了可調(diào)諧FFP驅(qū)動(dòng)放大電路和SD卡硬件電路,解決了容性負(fù)載導(dǎo)致的驅(qū)動(dòng)波形失真問題。在系統(tǒng)軟件設(shè)計(jì)上,首先開發(fā)完成了SD卡的驅(qū)動(dòng)、DAC驅(qū)動(dòng)和ADC驅(qū)動(dòng),并針對各個(gè)模塊的驅(qū)動(dòng)利用上位機(jī)進(jìn)行調(diào)試,使模塊達(dá)到預(yù)期的狀態(tài)。然后完成了uC/OS-III嵌入式實(shí)時(shí)操作系統(tǒng)和Fatfs文件系統(tǒng)的移植工作,利用操作系統(tǒng)來管理系統(tǒng)的軟硬件資源。為了配合操作系統(tǒng)的使用,本文設(shè)計(jì)了一種簡單的內(nèi)存管理方式。在數(shù)據(jù)的存儲上,利用Fatfs文件系統(tǒng),實(shí)現(xiàn)了將LCD截圖以BMP格式和AD采樣值以TXT格式保存在SD卡中。最后,利用GUI圖形庫設(shè)計(jì)了圖形用戶界面,完成波形圖像數(shù)據(jù)顯示。為了獲取更高精度的光纖光柵反射譜信號,首次將并行數(shù)據(jù)采集方法應(yīng)用于光纖光柵譜的采集中,并完成了3個(gè)AD并行工作的軟硬件設(shè)計(jì),提高了光纖光柵反射譜的采集點(diǎn)數(shù),為高精度、高速率光譜擬合奠定了基礎(chǔ)。為了進(jìn)一步提高系統(tǒng)的測量精度,本文實(shí)現(xiàn)了嵌入式環(huán)境下的Levenberg Marquardt(LM)算法并用于光纖光柵反射譜的擬合,得到反射譜峰值的精確位置。同時(shí),利用應(yīng)力光柵對溫度光柵傳感器進(jìn)行定標(biāo),完成環(huán)境溫度到傳感光柵波長的變化。較傳統(tǒng)方案相比,本系統(tǒng)完全不依賴于PC,實(shí)現(xiàn)了數(shù)據(jù)采集存儲,光纖光柵反射譜波長的擬合定標(biāo)等。經(jīng)測試,利用本課題提出的高速數(shù)據(jù)采集方案和實(shí)現(xiàn)的LM擬合算法,解調(diào)系統(tǒng)解調(diào)的中心波長漂移小于15pm。結(jié)合溫度傳感光柵的敏感系數(shù)ξ=10.3 pm/ ℃,系統(tǒng)解調(diào)溫度分辨率小于1.5 ℃。
[Abstract]:Fiber Bragg grating (FBG) sensors have the advantages of strong resistance to electromagnetic interference, corrosion resistance, high precision, simple structure and low price. The key of fiber Bragg grating sensing technology is demodulation system, which develops and designs a set of low cost, Portable demodulation system is of great significance to expand the application of fiber Bragg grating sensor technology. Firstly, this paper starts with the theoretical research of fiber grating sensor. The tunable fiber Fabry-Perot FFP filter is selected as the demodulation method of this system, based on the detailed analysis and comparison of five common demodulation methods of fiber Bragg grating, and the tunable fiber Fabry-Perot FFP filter is selected as the demodulation method of the system. According to the overall design of the fiber grating demodulation system, the hardware and software development of the fiber grating demodulation system is completed. The specific contents are as follows: in the system hardware design, the STM32F4 chip processing core is selected. The tunable FFP driver amplifier circuit and SD card hardware circuit are designed and implemented to solve the problem of waveform distortion caused by capacitive load. In the system software design, the SD card driver driver and ADC driver are first developed. According to the driver of each module, the module is debugged by the host computer to make the module achieve the expected state. Then, the transplant of the uC/OS-III embedded real-time operating system and the Fatfs file system is completed. In order to cooperate with the use of the operating system, this paper designs a simple memory management method. In the data storage, the Fatfs file system is used. The LCD screenshots are saved in the SD card in BMP format and AD sampling value in TXT format. Finally, the graphical user interface is designed by using the GUI graphics library to display the waveform image data. The parallel data acquisition method is applied to the acquisition of fiber grating spectrum for the first time, and the hardware and software design of three AD parallel work is completed, which improves the collection points of fiber Bragg grating reflectance spectrum and is of high precision. In order to further improve the measurement accuracy of the system, the Levenberg Marquardt LM algorithm in embedded environment is implemented and used to fit the reflection spectrum of fiber Bragg gratings, and the exact position of the peak value of the reflection spectrum is obtained. The temperature grating sensor is calibrated by stress grating to change the temperature from the ambient temperature to the wavelength of the sensor grating. Compared with the traditional scheme, the system is completely independent of PC-dependent, and realizes the data acquisition and storage. The wavelength fitting calibration of fiber Bragg grating reflectance spectrum, etc. By testing, using the high speed data acquisition scheme and the LM fitting algorithm proposed in this paper, The center wavelength shift of demodulation system is less than 15pm.The sensitivity coefficient of temperature sensing grating is 10. 3 pm/ 鈩，

本文編號：1561116