摘要
大口径大视场地平式望远镜长时间曝光时,主焦点探测器会由于地球自转产生像旋,即视场中除中心外其余星体均绕视场中心旋转,进而导致目标不能正确提取与观测。为消除图像旋转的影响,某大口径大视场望远镜的消旋跟踪精度需小于5″。本文根据星体像旋原理对主焦点探测器像旋的位置特性和速度特性进行系统分析及实验验证,提出采用双电机驱动消间隙消旋机构进行消旋,利用复合电流指令控制方法消间隙并进行控制。实验结果表明:像旋特性符合消旋公式,测量误差不超过2%。最终在低速15(″)/s及高速170(″)/s时消旋机构的跟踪精度小于1″,进行高变速切换即7.86°sin(2π×0.5t)时,控制精度仍然小于1″,采用双电机消间隙控制方法可有效提高系统的稳定性和精度。
Owing to the Earth’s rotation,image rotation always appears on the primary focus detector during the long exposure of Alt-Az telescopes with large aperture and wide field of view.This implies that except for the central point,other stars rotate around the center of the field of view;thus the target cannot be accurately identified and observed.To eliminate the image rotation,the de-rotator tracking error of a telescope with a large aperture and wide field of view should be less than 5″.The position and velocity of the image rotation of the primary-focus detector were analyzed and verified based on the star rotation principle.Subsequently,a dual-motor driving de-rotator system was designed,where the clearance of the mechanism was removed by the recombination current command.The experimental results indicate that the image rotation characteristics are consistent with the expression of image rotation,and the measurement error is less than 2%.The dual-motor diving de-rotator system can improve the stability and accuracy of the tracking system;thus the tracking accuracy of the de-rotator mechanism can be less than 1″both at a low velocity of 15(″)/s and at a high velocity of 170(″)/s.In addition,the tracking error remains less than 1 arcsec when the de-rotator operated at a variable and high velocity of 7.86°sin(2π×0.5 t).
作者
李玉霞
王帅
王建立
李洪文
曹玉岩
刘洋
LI Yu-xia;WANG Shuai;WANG Jian-li;LI Hong-wen;CAO Yu-yan;LIU Yang(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2021年第4期749-762,共14页
Optics and Precision Engineering
基金
国家自然科学基金资助项目(No.11803035,No.11973041)
天文联合基金资助项目(No.U2031126)。
关键词
望远镜
双电机消间隙
大口径大视场
消旋控制
地平式望远镜
telescope
dual motor anti-backlash
large caliber and field of view
de-rotator control
altazimuth telescope
