英文文獻(xiàn)及翻譯一種精確測量傾斜角度的光學(xué)傳感器畢業(yè)論文(編輯修改稿)
2024-07-22 14:43 本頁面
【文章內(nèi)容簡介】 incident direction is perpendicularly to the reflection plane。 （6）Where andrepresent the diffraction index of the two medias. The closer the two reflection indexes the less light reflected. When equals to there is no reflection occurring at this surface.While building the sensor one of the most important requirements is to make sure that the centers of all optical ponents are positioned on the same line, . the optical axis. Due to mechanical tolerance and the precise requirements of the sensor head, a fine tune on the alignment of the optical head is necessary to make sure the sensor can work well. The method begins with aligning the laser to enable the laser beam parallel to the base plate that all the optical ponents will be mounted on. Subsequently install the beam splitter. The direction of laser beam will be change by a right angle and incident to the liquid oil box. Adjust the beam splitter until the laser beam incident to the liquid oil box perpendicular. Install beam expander to convert the parallel beam into a spherical laser beam. Align the beam expander axis with the system optical axis. The reflected wave fronts ing from glass surface and oil surface will go through beam splitter and change its direction at right angle by mirror to enter camera. The alignment of camera makes ensure the laser beam to be imaged at the center of the imaging plane. That is, the imaging axis is normal to the imaging plane. Furthermore, the method needs to further align the liquid oil box with the three screws 10 mounted in the oil box to ensure tilt angle within the measurement range. A pattern with circular fringes will appear. Adjust the screw 10 until the center of the fringe pattern positioned in the center of image sensor as illustrated in Figure 4A.Fig. 3 Schematic diagram of oil boxFigure 3 shows the details of liquid oil box. The first surface is formed by airglass, called airglass surface。 the reflection ratio is about 3% since the refraction index of air is 1 and the glass we used is around . The second surface is formed by glassoil, called glassoil surface. There is almost no reflection in this surface since we choose proper oil with the close refraction index with the glass. The third surface is constructed by the oil and air. So the reflection ratio is about the same as the first surface. The two reflected wave fronts by the first glassair surface and the third oilair surface will meet together and interference each other to form a pattern with circular interference fringes as illustrated in Figure 4. When the glass surface is parallel with oil surface the center will be positioned in the optical axis (Fig. 4A). The position of center of the circular fringes will shift when the tilt angle varies (Fig. 4B).Fig. 4A Interference fringe patterns (center position, non tilted)Fig. 4B Interference fringe patterns (side position, tilted angle)IV. CALIBRATIONIt is vital for calibration of the sensor to ensure an accurate and reliable measurement. A proper calibration makes sure that the center of the circular fringes is positioned in the center portion of the image sensor when the sensor is placed horizontally. The purposes of the calibration are not only
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