應用布拉格光纖光柵感測器於加工系統之溫升、變形與動態特性之精密量測與遠端監控

Applying Fiber Bragg Grating Sensors to Precision Measuring Temperature, Deformation and Dynamic Characteristics of Machining Systems with Remote Monitoring

凃哲維(Che-Wei Tu)

指導教授 ： 馬劍清

國立臺灣大學/工學院/機械工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201902025

摘要

布拉格光纖光柵（Fiber Bragg Grating, FBG）是一種能夠同時對溫度、變形以及振動等物理量同時進行量測的新興感測器。其形態為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；另一特點為以光訊號進行傳遞，不受環境電磁訊號干擾；而訊號只在纖核內傳遞，使感測器有防水與耐高熱的能力。最重要的是全部資訊皆在一條光纖中，使得在實際應用上可以減少許多的軟硬體成本。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，因此對先進感測器的研究更是特別重要。
本文在硬體端方面則提出解析方式將其物理特性解耦合來達成溫升與振動的同時量測，此外與熱電偶、位移計等相關感測器的量測進行比較，確認光纖感測器的可靠度與準確性，軟體端方面則以Matlab程式語言開發其量測系統，接著串聯商用的聯網系統，達成智慧機械與工業4.0的目標。
本文的在實驗部分則著重應用於工業上相關問題的量測，總共分成三大部分：第一部份為加工馬達系統各部位的溫升、應變、熱膨脹係數以及振動位移等物理量，並實際模擬零件損壞，比較馬達在異常訊號下的量測差異；且將此系統應用至電動自行車馬達驅動模組之量測。第二部分先探討光纖原始波長飄移在單純受力與受熱的影響，並推廣至兩者耦合後的殘留波長飄移。而待測物則著重於加工的工件，包含在磨削、焊接與銑削不同加工方式下的加工工件之溫升、應變，並透過雙光纖法解耦合力與熱應變，最後討論材料在加工後的殘留應變。在第三部分則充分發揮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；實際將光纖埋入衝床的衝模內部，解析其衝擊訊號與衝子的連結，並以即時交互相關量測系統解析訊號間的相關係數，建構出數個判別衝子損壞的特徵。

關鍵字

布拉格光纖光柵 ； 感測器 ； 工業量測 ； 工具機 ； 馬達 ； 加工工件 ； 殘留應變 ； 衝模損壞特徵 ； 智慧機械

並列摘要

Fiber Bragg grating (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. Besides, the goal to measure multiple points could be achieved by using multiple grating embedded in one single FBG. Another feature of FBG is that its central wavelength signal is transmitted as an optical signal so it will not be affected by environmental electromagnetic signals. We also can use it in some harsh environment, like machining, because of its ability to resist corrosion and high temperature. The most important part of the FBG sensor is that all of the information included in the one single FBG so it can reduce costs of hardware and software. 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 advanced sensors is particularly important.
In this paper, the simultaneous measurement of temperature and vibration has been achieved by decomposing physical features of FBG on the hardware side. Moreover, the measurement results of FBG compared with other commercial sensors such as thermocouples and displacement meters to validate the reliability and accuracy of FBG sensors. Furthermore, the real-time measurement system developed in Matlab programming language on the software side, and then connecting data with a commercial intelligent system to realize the goal of the Internet of things (IoT) and industry 4.0.
The experimental part of this paper focuses on practical industrial problems, it is divided into three parts. First, measuring the temperature, thermal strain, coefficient of linear thermal expansion and vibrations of the various parts of the machining system such as bearing house and motor. Besides, the bearing with man-made defect is installed in this system to verify the superior measurement capability of FBG toward the system exception, and finally applying the FBG system to the measurement of commercial electric bicycle’s motor. Second, discussing the effect of wavelength drift of the FBG when the FBG has endured the force and heat and then extending the result to residual wavelength drift when they’re coupling together on the real machining situation. According to these principles, we could measure the temperature, force strain, thermal strain and residual strain on the workpiece during machining process such as grinding, welding and milling by utilizing dual FBG method. Furthermore, we also compared the value of residual strain with different machining process quantitatively. Third, utilizing the characteristics of the sensor, like light transmission and lightweight, actually embedded the FBG inside the die of the punching machine, and analyzing the connection between the impact signal and quality of die to build several damaged features of punch. Also, we construct the real-time cross-correlation measurement system to determine the punch is damaged or not with correlation coefficient and applying this system to the punching process practically.

並列關鍵字

Fiber Bragg Grating ； sensor ； industrial measurement ； machine tool ； motor ； workpiece ； residual strain ； damaged features of die ； intelligent machine

參考文獻

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