光子都卜勒干涉儀與時域光學反射式相位量測儀 之高速碎片量測與智慧工廠監測

Optical Fiber Interferometer and Phase Optical Time-Domain Reflectometer for Ultra-high Speed Fragment Detection & Smart Factory Monitoring

李鑫(Hsin Lee)

指導教授 ： 李世光 ； 吳文中

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201903981

摘要

光學檢測的發展，日新月異，各種特殊的量測應用也逐步地出現在各個應用領域。在多種光學量測系統中，經常運用干涉原理來進行系統架構，本論文的研究過程中，運用干涉原理開發出兩種應用領域有極大差異的高性能系統。第一種系統的開發乃是基於複合材料的應用範圍在今日航空器中日漸廣泛，所以一種可以量測超高速衝擊碎片的飛行路徑和速度的需求益發重要。第二種應用乃是基於今日隨著工業4.0的科技發展，智慧工廠逐漸成為各大科技的前進趨勢，不論是製程上的優化或是設備儀器的維修與照顧，工廠裡的監測系統也變得越來越重要。基於前述應用情境，因此本研究之目的乃著眼於開發碎片量測與智慧工廠監測等兩個光學系統。
本論文之碎片量測系統目標為量測碎片待測物之飛行過程，探討碎片待測物經過瞬間高電壓產生脈衝爆炸事件過程之影響，並模擬待測物結構在爆炸事件之訊號與驗證。結合光纖通訊技術與光子都卜勒干涉儀量測待測物反射回光與參考光在時序上之拍頻干涉訊號，其拍頻訊號經由連續小波轉換進行時頻分析事件在時序上所發生的頻率定位，接著以影像處理描繪出碎片待測物之速度歷程並加以積分繪製碎片飛行歷程。本實驗之系統可成功量測到1000 m/s以上之速度，並且可見量測碎片之最終速度與設置電壓呈現相對關係。
工廠監測系統以時域光學反射式相位量測儀(Phase Optical Time-Domain Reflectometer, φ-OTDR)作為實驗基礎架構，本實驗使用線性調頻(Linear Frequency Modulation, LFM)脈衝作為輸入光纖檢測區之訊號，搭配匹配濾波提升空間解析度、信號訊雜比，並且使用相位解調方法在實驗中取得相位，本系統所使用100 ns脈衝寬度，頻率掃描範圍為150 MHz，經由實驗量測出空間解析度為0.5967公尺，以100 z和2 Vpp電壓驅動圓柱體壓電致動器，成功量測最小到應變0.361 nm/m ，驗證驅動電壓與對應光纖軸向應變呈現正相關性，並且成功量測100 Hz和500 Hz頻率變化模擬儀器損壞造成自然頻率偏移。

關鍵字

光學感測器 ； 光子都卜勒干涉儀 ； 高速衝擊檢測 ； 時域光學反射式相位量測儀 ； 智慧工廠監測 ； 分佈式振動感測

並列摘要

The development of optical inspection techniques is rapidly improving, and those specific measuring methods are gradually applying in various fields. In a variety of optical measuring systems, interferometry is often used to carry out the system architecture. In this thesis, two high-performance systems with extremely different application fields were developed by using interferometry as their fundamental principle. The first system is developed to handle the need associated with the wide spread utilization of composite materials in aircraft nowadays, the technique to measure the flight path/time of ultra-high speed fragment is urgent need. The second application is targeted towards the applications of Industry 4.0. Smart factories are gradually becoming the major technology trend. Whether it is process optimization or equipment maintenance, the monitoring system in the factory is becoming ever more important. Based on the aforementioned application scenarios, the purpose of this study is to develop two optical systems for ultra-high speed fragment measurement and smart factory monitoring.
The goal of the ultra-high speed fragment measurement system of this thesis is to measure the flying process of the fragment. I discussed the influence between the explosion triggered by transient high voltage and measured the signal, and simulated the relation between the structure of explode object and measured the signal to verify the system. This optical measurement method combines the fiber-optic communication technology with photonic Doppler velocimetry to measure the beat signals generated by the temporal interference of sample beam and reference beam. These beat signals were analyzed by continuous wavelet transform, one kind of time-frequency analysis, to locate the frequency occurring in time series. Then I used image processing technology to plot the velocity profile of the object, and integrated it to get flying position profile. The system can successfully measure speeds above 1,000 m/s, and it can be seen that the terminal velocity of the measured fragments is related to the setting voltage.
The factory monitoring system uses phase optical time-domain reflectometer (φ-OTDR) as the experimental infrastructure. In this experiment, linear frequency modulation (LFM) pulse was used as the signal input into fiber under test (FUT). With the match filter, spatial resolution and signal-to-noise ratio were enhanced. The phase demodulation method was used to obtain the phase information in the experiment. In this system, laser pulse width is 100 ns, frequency sweep range is 150 MHz, and spatial resolution is 0.5967 m. The measured cylinder piezoelectric actuator was driven at 100 Hz with various voltage, 2 Vpp, successfully measuring a minimum strain of 0.361 nm/m. The driving voltage was verified that positively correlated with the corresponding fiber axial strain, and the frequency shifts due to assumed instrument damage at 100 Hz and 500 Hz were successfully measured.

並列關鍵字

Optical sensor ； PDV ； High-speed impact testing ； Smart factory monitoring ； Distributed vibration sensing

參考文獻

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