- 學位論文
開發布拉格光纖光柵感測器量測系統於機械加工系統之溫升、變形與振動特性之分析
Developing Fiber Bragg Grating Sensor System for Precision Measuring Temperature, Deformation and Vibration Characteristics of Machining Systems
摘要
布拉格光纖光柵（Fiber Bragg Grating, FBG），主要利用光罩寫入法製作光柵結構以達到感測器的功用；可由光訊號與電訊號間的能量轉換來量測波傳訊號，並解析其頻域訊號，此外光纖光柵是一種可同時針對溫度、變形以及振動等物理量同時進行量測的新興感測器；其外觀為一徑細質輕的線性幾何形狀，因此能夠埋入結構物內部進行量測，亦能利用多光柵光纖來達成多點的同時監測；由於近幾年機器學習與工業4.0等技術興起，對於巨量資料的要求增加，因此對資料的整理、數據的分析和不同訊號整合之要求遽增，而光纖光柵感測器便扮演至關重要的角色。 本文使用的解析方式可將光纖量測之物理訊號解耦合以達到同時量測溫升與振動之目的，並將其應用於工業相關問題量測，內容主要可分為四大部分：第一部份為高速內藏式主軸各光柵段之溫升、應變、熱膨脹係數以及振動位移等物理量，以及比較內外部熱伸長量之差異與熱傳遞之方向，並將量測結果與實驗室自行開發的數位影像相關法相互驗證，確立光纖光柵感測器量測之正確性。第二部分則是探討高硬度材料的高速鋼在銑削加工方式下的溫升、應變與加工後的殘留應變，其中當光纖原始波長飄移同時受力與熱的影響時，可以透過雙光纖法解耦合力與熱應變。第三部分為發揮光纖光柵感測器光傳輸與徑細質輕的特性，取代以往電訊號感測器的不穩定性，實際將光纖埋入機械手臂內部的馬達外殼上，解析其在運轉過程中之溫升與振動量，並與熱電偶相互比較，驗證光纖光柵感測器量測之準確性。最後，第四部份則是長時間監測壓縮彈簧系統之變形量，且以交互相關量測系統解析訊號間的相關係數，用於判別彈簧避震器是否有損傷產生，以此降低成本並保障設備之安全。
並列摘要
The structure of fiber Bragg grating (FBG) is built on photomask to achieve the function as a sensor. The energy conversion between optical signals and electrical signals is used to measure wave propagation signals and analyze their frequency domain signals. Besides, FBG is an emerging sensor which can be used in the measurement of temperature, deformation, and vibration simultaneously. FBG based on its linear geometry with lightweight, it can be buried inside the structure for measurement. Moreover, the goal to measure multiple points could be achieved by using multiple grating embedded in one single FBG. To sum up, due to the rise of computer science and technology related to machine learning and industry 4.0, the demand for huge amounts of data has increased so the research on FBG is particularly important. In this thesis, the simultaneous measurement of temperature and vibration has been achieved by decomposing physical features of FBG. The experimental part of this thesis focuses on practical industrial problems, it is divided into four parts. First, measuring the temperature, thermal strain, coefficient of linear thermal expansion and vibrations of the various parts of the built-in high-speed spindle. The difference between internal and external thermal displacement and the direction of heat transfer is discussed. Besides, the validity of these measurements is verified via Digital Image Correlation (DIC) developed by the laboratory. Second, the temperature rising, variation of strain and residual strain of the workpiece which is made from high speed steel (ASP-60) under the milling process are discussed. Since the wavelength drift of the FBG is caused by both force and heat, the dual FBG method is chosen to decouple the force strain and the thermal strain. In the third part, the FBG is attached to the motor case which is inside the mechanical arm to analyze the temperature and the vibration characteristic. The accuracy of FBG sensor is verified by comparing the measurement result with the thermocouples. Finally, the FBG sensor is applied to the long-term monitoring of the deformation for spring system. Also, we construct the cross-correlation measurement system to determine the spring is damaged or not with correlation coefficient.