LAMOST光纤定位控制系统的优化研究

发布时间：2018-06-08 05:13

本文选题：LAMOST + 光纤定位单元　；参考：《中国科学技术大学》2015年硕士论文

【摘要】：LAMOST(大天区面积多目标光纤光谱天文望远镜)是一架我国科学家自主创新设计和研制的世界上光谱获取率最高的反射施密特望远镜。作为LAMOST关键性技术之一的并行可控的光纤定位技术也被应用到BigBOSS国际项目中,这对我国来说既是机遇又是挑战。为了提高光纤定位单元的走位精度,完善摄像机测量标定系统,本文以提高精度为核心,分析标定过程中涉及到定位精度的各个环节,根据实际情况作出相应的改进。主要完成的任务如下： 1.对多项式摄像机标定模型在光纤定位单元标定中的应用做了深入研究。详细的介绍了标定模型中参数的选择问题以及对应参数取点多少才能达到标定精度要求和取点方式等,通过走点实验得出,随着光点数目的适量的增加,标定精度也越来越高,要根据实际情况选择采用20参数还是30参数进行标定。对比2KCCD和4KCCD摄像机在采用相同的处理方式下对标定精度的影响大小。 2.采用30参数对标定靶光点进行多项式拟合研究多幅图片的最佳处理方式。通过7种处理方式对摄像机拍摄的多幅图片数据进行处理对比发现,预处理时把连续拍摄的10幅图片得到数据平均值一组数据进行计算可以得到较小的误差值,提高了标定效率和标定精度。 3.在传统模型S曲线的基础上对步进电机加减速曲线进行了优化和设计,提出了单个三次方程的S曲线的方法对步进电机的升降速度进行控制,该方法计算量小,方程式简单。在被控对象的约束条件不同时,只需灵活设置初始参数(启动频率、稳定频率、加速时间)便可获得相应曲线,等脉冲间隔方式对曲线离散,并使用牛顿迭代法精确求出频率大小。经反复试验得到一个最优结果,最终求得的频率组可使得步进电机工作时产生的过冲量大、稳定性差、噪音大等现象得到抑制。 4.模拟了高密度子节点通讯时Zigbee的通讯性能。通讯问题的产生不仅与所写的通讯程序有关,与Zigbee的规范问题也相关,随着Zigbee的持续发展和市场需求的增长以及对通讯程序编写的规范化使问题得到了改善。
[Abstract]:LAMOST (large Sky area Multitarget Optical Fiber Spectral Telescope) is a reflective Schmitt telescope which is designed and developed by Chinese scientists and has the highest spectral acquisition rate in the world. As one of the key technologies of LAMOST, the parallel and controllable optical fiber positioning technology is also applied to Bigboss international project, which is both an opportunity and a challenge for our country. In order to improve the positioning accuracy of the optical fiber positioning unit and improve the camera measurement and calibration system, this paper analyzes all aspects of the positioning accuracy involved in the calibration process, and makes corresponding improvements according to the actual situation. The main tasks are as follows: 1. The application of polynomial camera calibration model in optical fiber positioning unit calibration is studied. This paper introduces in detail the selection of parameters in calibration model and how many points of corresponding parameters can reach the calibration accuracy and how many points can reach the calibration accuracy. Through the walking point experiment, it is concluded that with the increase of the number of light points, the calibration accuracy becomes higher and higher. Choose 20 parameters or 30 parameters to calibrate according to the actual situation. The effect of 2 K CCD and 4 K CCD camera on calibration accuracy is compared in the same processing mode. 2. 2. The optimal processing method of multiple images was studied by polynomial fitting of the calibration targets with 30 parameters. By comparing and analyzing the image data taken by the camera in 7 kinds of processing methods, it is found that the average value of a group of data can be obtained by calculating the average data set of 10 pictures taken continuously during the preprocessing, and the error value can be obtained. The calibration efficiency and precision are improved. 3. Based on the traditional model S curve, the acceleration and deceleration curve of step motor is optimized and designed, and the method of S curve of single cubic equation is proposed to control the speed of step motor. The calculation of this method is small and the equation is simple. When the constraint conditions of the controlled object are different, the corresponding curves can be obtained by setting the initial parameters (starting frequency, stable frequency, acceleration time) flexibly, and the curves are discretized in equal pulse intervals. And the Newton iteration method is used to calculate the frequency accurately. After repeated experiments, an optimal result is obtained, and the frequency group obtained finally can restrain the phenomena of excessive impulse, poor stability and high noise produced by the stepping motor in operation. 4. The communication performance of Zigbee during high density sub-node communication is simulated. The problem of communication is not only related to the written communication program, but also to the specification of Zigbee. With the continuous development of Zigbee and the growth of market demand, the problem is improved with the standardization of communication program.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH751;TP273

【相似文献】