非接触式指向反射镜激光动态测试方法研究

	非接触式指向反射镜激光动态测试方法研究
	王洋
学位类型	博士
导师	颜昌翔
	2014-07
学位授予单位	中国科学院大学
学位专业	光学工程
摘要	指向反射镜作为超光谱成像仪的关键部件，主要用于光路转折、对地物的运动补偿等。指向反射镜的位置误差和角速度误差直接影响超光谱成像仪的成像质量，因此指向反射镜的实时动态测试非常重要。目前用于检测指向反射镜角速度的方法为编码器直接联接测量法，该方法对指向反射镜本身的转动特性有耦合影响，所以需要采用非接触式的检测方法。指向反射镜运动特性的检测需要通过高精度的角度测量实现。非接触式角度测量方法主要为光学测角法，目前已有的光学测角法测角范围多数仅有几十秒~几分，无法同时满足指向反射镜测角范围和测角精度的要求，不能直接用于指向反射镜的实时动态检测。经纬仪是工程中广泛应用的角度测量设备，主要用于指向反射镜的静态角度测量，也无法实现大范围内的实时的动态检测。根据工程项目对指向反射镜的检测系统提出的要求，研制了一套非接触式指向反射镜激光动态测试系统。检测系统将被检测指向反射镜的转动转化为激光光斑在线阵CCD上的移动，根据激光光斑的移动计算指向反射镜的角速度。系统主要由一字线激光器、滤光片、阵列平面反射镜、线阵CCD、图像采集子系统以及计算机等组成，特殊设计的阵列反射镜通过一片线阵CCD复用保证系统在增大测角范围的同时不降低测角精度。本文首先介绍系统的相关指标、基本工作原理及构成；而后利用齐次坐标变换法建立了系统的数学模型，数学模型中引入了各元件的加工、装调误差量，通过蒙特卡罗法进行了系统的误差分析，结果表明要实现检测系统要求的精度，对各元件的加工、装调精度要求很高。为了降低对加工装调精度的要求，提出了利用经纬仪标定指向反射镜的角位置，利用三次多项式拟合计算被检测指向反射镜的角位置和CCD上激光光斑所在的位置关系曲线，测量指向反射镜的转角范围内任意角位置，根据CCD的帧频可计算指向反射镜的角速度，误差分析结果表明此种方法适用于本检测系统。研制了系统的原理样机，搭建了指向反射镜激光动态测试系统的实验平台，完成了相关检测实验。对影响静、动态测量精度的因素进行了详细的分析，对实验数据进行分析，给出了最终的检测结果：系统静态测角精度为3″，角速度检测精度优于±7%，满足预期指标要求。由于本文是针对实际工程应用的检测系统，在原理样机及实验结果基础之上进行了系统实用化设计，包括系统的光机设计、电子学设计及相关工装。对于检测系统的相关指标进行了详细的分析，提出了进一步进行指标优化的可能性。针对目前的大范围低转速检测在其他方面的需求，可将本检测系统应用于其他检测场合，本文最后给出了两种应用扩展的例子。
其他摘要	The scanning mirror is a key component on the hyperspectral imager, which is mainly used for optical transition and motion compensation. The angular errors and position errors of the scanning mirror have an effect on the image quality of the hyperspectral imager, so the dynamic test of the scanning mirror is very important to improve to the image quality of the hyperspectral imager. The encoder is often used to measure the angular velocity of the scanning mirror, and the contact measurement method would produce a certain angle measurement error, so it is important to raise a non-contact method for the scanning mirror measurement. In order to measure the dynamic movement of the scanning mirror in a quite large angular range, the dynamic continuous angular measurement with high accuracy must be realized firstly. And then the angular velocity of the scanning mirror can be analyzed according to the results of the angular measurements. Optical angular measurement methods are used widely among all the non-contact angular measurement methods. Most optical anglular measurement methods can not satisfy the requirements on the measurement range and accuracy at the same time. The measurement ranges of most optical methods are only a few seconds to several minutes, and they can not be applied to the dynamic angle measurement of the scanning mirror. The theodolite is widely used in angular measurement, but the theodolite can not realize real-time dynamic measurement. A non-contact laser dynamic measurement system for the scanning mirror is proposed in this dissertation according to the project requirements. The variation angle of the scanning mirror can be obtained according to the shifting of the laser facular on the linear CCD, and then the angular velocity can be calculated. A line laser, attenuator, array mirrors, linear CCD, image acquisition and computer subsystems are included in the system. A large angle measurement range is divided into five small angle ranges by the array mirrors, and the rotation angle can be measured by reusing a linear CCD to ensure the measurement accuracy. Firstly, the working principle and the basic structure are introduced in the dissertation.The mathematical model of the system is established with the homogeneous coordinate transformation method, which contains the errors of processing and alignment. According to the Monte Carlo method, the error distribution schemes of the system are performed through the absolute position error analysis and relative position error analysis .The results show that the error distribution schemes based on the relative position error analysis method can greatly reduce the requirements of the processing and alignment. Finally, the cubic polynomial fitting method is applied for the measurement. The function about the position of laser facular and the angular displacement can be calculated based on the cubic polynomial fitting. The angular displacement can be measurement by the theodolite and the position of laser facular is come from the computer. Compared to traditional angle measurement instruments, the system realizes non-contact dynamic angular measurement in wide measurement range. Each component in the measurement system is selected according to the relevant parameters, and the experimental platform is proposed.Before the experiments, the factors which have an effect on the measurement accuracy are analyzed. The final experimental results show that the rotation angle could be measured within 11°. The sensitivity and accuracy of angle measurement was 2.5″ and 3″. The accuracy of velocity measurement is better than ±7%. The measurement system is applied in the practical project, and some practical designs are gived based on the prototype and experimental results including optomechanical design, electronics design and related alignment design. The measurement system can be applied in other occasions, and two examples of the application are performed finally in the dissertation.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41481
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	王洋. 非接触式指向反射镜激光动态测试方法研究[D]. 中国科学院大学,2014.

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