毫秒级角位移绝对测量的光电信号扫描机理及细分误差实时修正研究

High precision, high resolution and strong spatial adaptability is an important development direction of angular displacement measurement.As the measuring demand continues to improve, the extraction quality and subdivision error of Moire fringe photoelectric signal has become the major constraint of dynamic measurement of millisecond angular displacement.Research on scanning extraction method and real-time subdivision error correction of high quality Moire fringe signal has important significance for the development of angular displacement measurement.Optics, mechanics and electronics analysis methods are integrated in the project. The coding design of encoder grating code disk, imaging scan of multiple windows, the mechanical alignment between light emitting element and light receiving element and real-time correction of electrical signal dynamic subdivision error is analysed. The extraction error of Moire fringe signal is researched deeply.Analysis and experiment methods are combined in the project. The impact of various factors on the photoelectric signal extraction quality is researched. The scanning principle of high quality Moire fringe signal is researched systematically.The correction limitations of each discrete subdivision error source are broken through. The unified correction model of dynamic subdivision error is established and the subdivision error is corrected in real-time. The reliability of angular displacement measurement is improved. The project will provide a solid theoretical foundation and technical support for the measurement of millisecond angular displacement.

高精度、高分辨力、强空间适应性是角位移测量发展的重要方向，随着测量需求的不断提高，莫尔条纹光电信号的提取质量及其细分误差已成为毫秒级角位移动态测量实现的主要制约因素。研究高质量莫尔条纹信号的扫描提取方法及其细分误差的实时修正对角度测量领域的发展具有重要意义。本课题利用光、机、电集成化分析手段，通过对编码器光栅码盘的编码设计、多窗口的成像扫描、发光/接收元件间的机械对位、电信号动态细分误差的实时修正等方面分析，对莫尔条纹信号的提取误差进行深入细化研究；利用分析与实验相结合的方式，研究各个影响因素与光电信号提取质量间的误差关系，对高质量莫尔条纹信号的扫描机理进行全面系统的综合分析研究；在此基础上，突破现有光电信号各离散细分误差源的修正局限性，建立动态细分误差的统一修正模型并实现实时修正，提高角度测量的可靠性，为进一步实现我国毫秒级角位移的精密测量提供坚实的理论基础和技术保障。

高精度、高分辨力、强空间适应性是角位移测量发展的重要方向，为了实现毫秒级分辨力光栅式角位移的测量，本课题首先从光学角度对光栅的设计、制作形成和空间滤波方法进行实验研究，建立了基于发散角、光源宽度的光电成像扫描模型，并验证了参数对光电信号质量的影响，又从自适应光学成像角度，利用CCD探测器代替传统光电二极管探测器，从光学波前角度建立了基于线性相位分集技术的编码器光学系统快速校正方法；然后，建立了基于高分辨力数字电位计+DSP+CPLD的莫尔条纹误差分析信号的演示验证系统；同时，提出了基于热敏电阻的光栅条纹信号幅度偏差实时修正方法；最后基于多倍角理论，提出了基于FPGA的光电位移信号高倍频细分方法并建立了细分系统。结果表明：以正弦波信号为输出模型的光电编码器，光源参数对正弦性和正交性有直接影响，在实验过程中编码器精度相差达到30%，信号稳定性好，而空间滤波成像处理可以减少光栅中高次谐波的含量，明显改善光栅信号的质量；-20℃~ +40℃温度范围内的精码信号补偿效果良好；采用本细分方案设置四倍频设计实验，该系统可以快速将频率增加到原来频率的4倍。这为进一步实现我国角位移精密测量提供了更为坚实的理论基础和技术保障。