为了解决传统抖动分析方法在TMT（Thirty Meter Telescope，三十米望远镜)三镜轴承上的局限性，提出了利用Gabor变换作为抖动性质及信号特性的评价方法。介绍了多加速度计的位置分布及连接方式，详细说明了加速度计在俯仰轴及方位轴上抖动信号的测试过程。在抖动信号数据处理中比较了时间序列法和周期图法的不足，提出了Gabor变换的新方法，Gabor变换可以截取任意时间段上的频谱信息的性质，在时-频域上分析信号的特征，使抖动分析更加真实可靠。最终在某2m级望远镜轴承上做了抖动测量实验，从实验结果可以看到2s内的频率特性曲线，接近0Hz的低频扰动比较敏感，50Hz噪声扰动一直存在，470Hz的高频信号时续时断。当轴承顺时针转动时，1s时有很明显的噪声信号；轴承反向转动时，1.5s~2s时噪声信号突出，降噪后低频噪声依然存在，但高阶频率被激励，保证了信号的真实性. Gabor变换的信号处理方法对于今后大型光电望远镜轴承抖动检测的研究具有一定借鉴意义。
Abstract
In order to overcome the limitation of the traditional jitter measurement analysis method for TMT (thirty-meter-telescope) tertiary mirror bearing, a mathematical method for the analysis of jitter properties called Gabor transformation was proposed. The location distribution and connection type of muti-accelerometers were introduced, and the measurement process of jitter signals at pitching axis and azimuth axis with accelerometers was fully illustrated. In jitter signal processing, the disadvantages of the time series analysis method and those of the periodogram method were compared. The new method called Gabor transformation was introduced, Gabor transformation could intercept the property of frequency spectrum information at any time interval, the characteristics of a signal was analyzed in time-frequency domain, it made the jitter analysis more real and reliable. At last, the jitter measurement test was performed on a 2m-long telescope, the frequency properties curve within 2s showed that the excitations with lower frequencies close to 0Hz are more sensitive, the noise excitation with 50 Hz always exists, and the high frequency signal with 470 Hz is on and off; when the bearing rotates clockwise, there is an obvious noise signal within 1s; when the bearing rotates counterclockwise, noise signals is significant within 1.5s-2s; lower frequency noise signals still exist after denoising, and higher frequency ones are excited, the realness of the signal is guaranteed. Gabor transformation provided a reference for the future bearing jitter detection of large photo-electric telescopes.
关键词
三十米望远镜 /
大型轴承 /
抖动测量 /
加速度计 /
Gabor变换
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Key words
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thirty-meter-telescope；large bearing；jitter testing；accelerometer；Gabor transformation
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参考文献
[1] Ford V, Carter C, Delrez C,et al .Jitter Studies for the Secondary and Tertiary Mirror Systems on the Thirty Meter Telescope [J]. Proc. SPIE 9151, 2014, 9151.
[2] 殷广东. 大口径望远镜轴系的抖动测量[D].北京：中国科学院大学, 2013.
YIN Guang-dong. Jitter measurement of large aperture telescope shafting[D]. Beijing: University of the Chinese Academy of Sciences, 2013.
[3] Sobek R D. Mitigating wind induced telescope jitter [J]. SPIE, 2005, 5810:1-10.
[4] Glaese R M, Michael S. Vibration Mitigation for Wind-Induced jitter for the Giant Magellan Telescope [J]. Proc. SPIE, 2012, 8444.
[5] Skidmore W, Travouillon T, Riddle R,et al. Experiments at the W.M. Keck Observatory to support the Thirty Meter Telescope Design Work [J]. SPIE, 2010, 7733(6):54-58.
[6] 赵宏超，张景旭，杨 飞. TMT三镜系统tilt轴轴承方案研究[J]. 红外与激光工程，2015,44(1): 122-126
ZHAO Hong-chao, Zhang Jing-xu, Yang Fei. TMT M3 system tilt axis bearing method[J]. Infrared and Laser Engineering, 2015,44(1):122-126
[7] 孙 航, 张海波, 曹立华, 等. 大口径光电探测设备主镜晃动的误差补偿[J]. 光学精密工程, 2014, 22(1): 85-91.
SUN Hang, ZHANG Hai-bo, CAO Li-hua,et al. Error compensation for primary mirror shaking of large aperture optical detection equipment[J]. Optics and Precision Engineering, 2014, 22(1): 85-91.
[8] 杨 飞，刘国军，赵宏超，张景旭. 30m望远镜三镜系统刚度分配与分析[J].光学精密工程，2016,24(1):152-159.
YANG Fei, LIU Guo-jun, ZHAO Hong-chao, ZHANG Jing-xu. Stiffness allocation and analysis of TMT M3S[J]. Optics and Precision Engineering, 2016, 24(1): 152-159.
[9] 安其昌，张景旭，杨 飞, 等. 大口径望远镜风载分析综述[J]. 机电工程，2015,32(12):1649-1652.
AN Qi-chang; ZHANG Jing-xu; YANG Fei. Overview of wind load analysis of large telescope [J]. Journal of Mechanical＆Electrical Engineering. 2015,32(12): 1649-1652.
[10] 杨晓霞，孟浩然，阴玉梅，等. 利用加速度计的大型光电望远镜抖动测量方法[J]. 电子测量与仪器学报, 2013,27(9):823-830.
YANG Xiao-xia, MENG Hao-ran, YIN Yu-mei. Jitter measurement for large opto-electronic telescope using accelerometers[J]. Jouranal of Electronic Measurement And Instrument, 2013,27(9): 823-830.
[11] 安其昌，张景旭，杨 飞. 基于加速度信号的 TMT 三镜镜面 jitter 测量[J]. 红外与激光工程, 2015.44(10):2970-2974.
AN Qi-chang, ZHANG Jing-xu, YANG Fei. TMT tertiary mirror jitter measurement with acceleration signal [J]. Infrared and Laser Engineering, 2015.44(10): 2970-2974.
[12] 李 立，徐燕申，孙容照. 加速度计安装方式对振动测量的影响[J]. 机械设计, 1989(1):31-34.
LI Li, XU Yan-shen, SUN Rong-zhao. The influence of accelerometer installation method for the vibration measurement [J]. Mechanical Design, 1989(1):31-34.
[13] Mayo J. Mechanical jitter Measurement Results for Large Ground-Based Telescopes [J]. SPIE, 2004, 5495:98-103.
[14] 丁 科，黄永梅，马佳光，等. 抑制光束抖动的快速反射镜复合控制[J]. 光学精密工程，2011,9(19): 1991-1997.
DING Ke, HUANG Yong-mei, MA Jia-guang. Composite control of fast-steering-mirror for beam jitter [J].Optics and Precision Engineering, 2011, 9(19):1991-1997.
[15] 卢振坤，杨 萃，王金炜. 基于Gabor变换的超声回波信号时频估计[J]. 电子与信息学报，2013,35(3)：653-657.
LU Zhen-kun, YANG Cui, WANG Jin-wei. Gabor Transform Based Time-frequency Estimation of Ultrasonic Echo Signal [J]. Journal of Electronics & Information Technology, 2013, 35(3)：653-657.
[16]朱俊青，沙 巍，陈长征，等. 大口径空间相机像质的微振动频率响应计算[J]. 光学精密工程
2016,24(5):1118-1127.
ZHU Jun-qing, SHA Wei, CHEN Chanzheng,et al. Frequency response of imaging quality by micro-vibration for large-aperture space-borne telescope. Optics and Precision Engineering, 2016, 24(5):1118-1127.
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