Developmental Study on Control of Large Telescope System

大型望远镜系统控制的发展研究

• 批准号: 61840002
• 负责人: YAMASHITA Yasumasa
• 金额: $ 8.32万
• 依托单位: Uiniveresity of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61840002/
• 关键词: Large Astronomical Telescopes; Reflecting Telescopes; Meniscus Mirrors; Actuators; 鏡面制御; 軽量化主鏡; 能動支持

The use of thin meniscus mirror of 20-cm thickness is scheduled for the 7.5-m projectg. Such a thin mirror is easily deformed by a self weight.d It is, therefore, intended to control the supporting fprce of the mirror and to control the mirror surface by the use of actuators. Deflection calculations of the mirror due to the self wight were carried out by the finite element method. It was found that about 390 support points are needed and the accuracy of the supporting force must be as high as 1x10^<-4> for the meximum load of 50-kg. It was concluded that the actuator consisting of a ball-screw and a spring is the most reliable device. The ball-srew is rotated by a motor and pushes the spring transforming the vertical motion to a force. The force is measured by a load-cell. The difference of force signal from the calculated value is fed back to the motor to cancel the difference. The test actuator was constructd and tested extensively. Modifying the load cell and several mechanical parts, the error in the axial support force was made as small as (+-) 5 g (max), which was eauivalent to the accuracy of the tuning-fork type load cell itself. Thus, it is concluded that this design of actuator can be used for controling the mirror surface.

7.5米的项目计划使用20厘米厚的薄弯月镜。如此薄的镜子很容易因自重而变形。因此，旨在通过使用致动器来控制镜子的支撑力并控制镜面。采用有限元法对镜子因自重引起的偏转进行了计算。结果发现，对于50公斤的最大负载，需要大约390个支撑点，并且支撑力的精度必须高达1x10 ^ -4 。结论是由滚珠丝杠和弹簧组成的执行器是最可靠的装置。滚珠丝杠由电机驱动旋转并推动弹簧，将垂直运动转化为力。力由称重传感器测量。力信号与计算值的差异被反馈到电机以消除差异。测试执行器经过广泛构建和测试。修改称重传感器和几个机械部件，使轴向支撑力的误差小至（±）5 g（最大），与音叉式称重传感器本身的精度相当。因此，得出的结论是，这种致动器的设计可用于控制镜面。

项目成果

山下 泰正: 東京天文台報. 21. 14-32 (1987)

山下康正：东京天文台报告 21. 14-32 (1987)

Y. Ymashita: "Preliminary Study on Decentring Errors and Optical Alignment of Reflecting Telescopes (Correction of Decentring Coma and Residual Astigmatism)" Tokyo Astronomical Observatory Report. 21. 14-32 (1987)

Y. Ymashita：“反射望远镜偏心误差和光学对准的初步研究（偏心慧差和残余像散的校正）”东京天文台报告。