拉格朗日內插法於穩態氫氣感測之應用

Application of Lagrange Interpolation on steady-state hydrogen sensing measurement

張沛乘(Pei-Cheng Zhang)

指導教授 ： 林坤緯

朝陽科技大學/資訊學院/資訊工程系/碩士(2012年)

摘要

本文分別提出基於微機電技術（MEMS）之氫氣感測系統與以FPGA 氫氣運算系統補足氫氣量測時缺少的感測值。本研究之氫氣感測系統結合標準CMOS 技術製作三個氣體感測器以及其輸出電路。藉由Switch 電路選擇不同的輸入感測器訊號，可用以選擇不同之感測器。感測元件結合放大器，可將感測訊號放大，以利量測與分析。FPGA 系統利用演算法彌補感測器測試時缺少之數據。
本研究以多項式內插法補足量測上缺乏的氫氣濃度相對應的感應電流值，本研究中使用三種不同的內插法，分別為線性內插法、牛頓均差內插法以及拉格朗日內插法模擬並和實驗值比較，由模擬得知拉格朗日內插法所模擬的資料最接近實驗量測值，因此我們以拉格朗日內插法，在FPGA 上實現即時氫氣感測系統。此外，運算出每一個內插點只需要30ns。綜合以上所述，本研究之氫氣感測系統具有：以較少數據建模、低運算複雜度、運算所需時間較短等優點。
本研究使用TSMC 35μm 製程製作出微感測器電路，再透過後製程塗佈感測材料做出氫氣微感測器，為了將感測器缺少之數據補齊，使用多項式內插法補齊數據，模擬氫氣濃度之精確度達1ppm，，相當適合運用於即時氫氣偵測。

關鍵字

拉格朗日內插法 ； Verilog ； 低運算複雜度 ； 氫氣感測系統

並列摘要

The purpose of this study is to fabricate hydrogen sensing system based on MEMS technology and to simulate the hydrogen sensing characteristics, for completing the lack data. The hydrogen sensing system included three hydrogen sensors and its output circuit, which were produced in standard COMS technology. The different gas sensing signals were output by the selection circuit. The sensing device with amplifier can enlarge the hydrogen signal, which was helpful measurement and analysis. The studied algorithm can compensate the lack measuring data. Finally, the gas sensing system were realized on FPGA.
In this studied, the polynomial interpolation methods were used to complete the lack data which were not measured during introduction hydrogen gas. Three different interpolation methods, including linear interpolation, Newton divided-different and Lagrange interpolation were used to compare with experimental data. From the simulated results, we find Lagrange interpolation method is the best way in data error. Hence, we realized the real-time hydrogen sensing system by adopting Lagrange interpolation method on FPGA. Furthermore, the requited computing time is to find out each hydrogen sensing data is only 30ns. The advantage of the studied hydrogen sensing system include modeling with less data, low computing complexity and short required computing time.
The micro sensing circuit was fabricated by TSMC 35um CMOS technology. After a clean process, gas sensing area were formed by depositing Pd metal. In order to complete the lack sensing data, the Lagrange interpolation method was used. The accuracy of simulated data that can reach 1ppm of hydrogen sensing system is suitable for the real-time hydrogen gas detecting.

並列關鍵字

Low computational complexity ； Verilog ； Lagrange interpolation ； hydrogen sensing system

參考文獻

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