- 學位論文
波長調制外差散斑干涉術應用於角度量測之研究
Wavelength-modulated heterodyne speckle interferometry for angular displacement measurement
摘要
本研究開發一套「波長調制外差散斑干涉術」，可用以進行精密滾轉角度量測。利用雷射二極體之波長可隨外加電流調制的特性，用以產生外差光源，可克服傳統利用旋轉波片、電光調制器及聲光調制器等商用外差光源調制元件所產生之缺點。該波長調制外差散斑干涉術搭配自行開發的相位調解程式，可擷取因待測物旋轉時所引入的角位移變化資訊，藉由弧長與轉動角度間的數學關係式，回推待測物之角位移量。本系統光學原理簡單、易於架設、成本低及待測物表面不需經過特別處理等優點，可克服其他滾轉量測系統的缺點，是一套極具開發價值的滾轉量測系統。 本系統之理論解析度可達1.08 ?deg，考慮環境雜訊、機械振盪等因素，經實驗證明本套系統可量測之最小解析度為0.00048°，靈敏度為0.081°/?deg，系統最大可量測之速度極限為0.29°/s，可量測之最大相對滾轉角度保守估計為0.08°，其原因主要受限於干涉訊號對比度消長的問題。 本論文除了針對可能造成量測系統的誤差進行討論外，也提供可能影響干涉訊號對比度之參數進行測定實驗結果，以期待未來能夠建構出適當的物理模型解釋干涉訊號對比度消長之現象以解決因其現象所造成量測範圍受限之缺憾。
並列摘要
This study presents a simple method to measure angular displacements by wavelength-modulated heterodyne speckle interferometer. We modulated the wavelength of laser diode by injection current to replace commercial component to produce heterodyne light source. In addition, the speckle interferometer has compact optical arrangement and reduction of the cost. And we designed an algorithm to calculate the phase variation which results from the object movement. The theoretical predication shows that the resolution is about 1.08 micro-deg. However, the experimental results verified that the minimum resolution is 0.00048° with considering the ambient perturbation and mechanical vibration. Then, the sensitivity can achieve 0.009°/micro-deg and the maximum velocity of measurement limited down to 0.29°/s. Unfortunately, the measurement range was confined because the interference contrast will disappear and grow up repeatedly when the object moves. The system is quite a potential in domain of rolling measurement if the issue before we mentioned was being solved.