Research and Development of Control Technology of Large Segmented Mirrors

在京都大学天文学系，3.8米望远镜项目目前正在进行中，该项目使用建造下一代超大型望远镜所需的技术。在本研究项目中，作为本望远镜项目的一部分，我们进行了以下研究。镜面支承系统的设计与研制我们进行了机械零件的试制，使镜面支承具有相同的承载能力。支撑系统在放置在镜子后面狭窄空间的望远镜的任何仰角下都不会产生任何扭矩。我们在试制过程中发现了一些问题，如间隙和接头的安装精度。用于调整反射镜支承系统的驱动器系统的研制我们改进并进行了驱动器系统的试制，使上述镜片支承系统的调整精度达到~10 nm。改进后的执行器可以放置在桁架结构…节点的正下方此外，即使在小负载条件下，也可以通过连接在由谐波齿轮驱动的执行器轴上的加压弹簧来稳定地工作。用于精密位置测量的非接触式传感器的测试继续进行了用于分段镜间相对位置测量的非接触式电感传感器的稳定性测试。我们发现，测量值对电缆的弯曲和面板的静力都很敏感。传感器的新驱动电路读出噪声小，但在长期稳定性测试中有一定的不稳定性。我们将研究具有稳定性和低读出噪声的驱动电路。分段镜之间相位差测量的基本技术的发展我们设计了一种相位差测量系统，该系统在望远镜焦点上使用扩展激光，在分段镜之间安装多个半反射镜。通过实验室光学测试，证实了该方法的基本原理。下一步是演示利用可调谐激光器的波长切换能力来调整镜面位置的最快程序。较少

In the department of astronomy of Kyoto University, the 3.8m telescope project is now in progress using the technology required to construct the next-generation extremely large telescope. In this research project, we conducted the following studies as a part of this telescope project.1. Designing and development of the mirror support systemWe carried out the trial manufacture of a mechanical part to support the segmented mirror with the same bearing power. The support system does not yield any torque under any elevation angle of the telescope, placed in the narrow space behind the mirror. We found a few problem such as backlash and the mounting accuracy of a joint from this trial manufacture.2. Development of actuator system to adjust the mirror support systemWe improved and also carried out the trial manufacture of the actuator system, which adjust the above mirror support system with an accuracy of 〜10nm. The improved actuator can be placed just below the nodes of the truss structure … More , and is stably-operated even under a small load condition by the pressurized spring attached to the actuator axis driven with a harmonic-gear.3. Test of the noncontact sensor for the accurate position measurementThe stability test of the noncontact inductance sensor for the relative position measurement among the segmented mirrors was continued. We found that the measured value is quite sensitive to bending the cables and also to the static of the facing plate. The new driving circuit of the sensor shows a small readout noise, but somewhat unstable in the long-term stability test. We will investigate the driving circuit having stability and low readout noise.4. Development of basic technologies to measure the phase differences between the segmented mirrorsWe designed the phase-difference measurement system using a spreading laser on the telescope focus and many half mirrors attached between the segmented mirrors. The basic principle was confirmed by the optical test in the laboratory. The next step is the demonstration of the fastest procedure to adjust the mirror position using the wavelength switching capability of the tunable laser. Less