基于液压支撑的大口径主镜稳像技术

Position control technology of large aperture mirror based on hydraulic support

望远镜的俯仰运动会使主镜相对镜室的位置发生改变,进而影响望远镜的稳定成像。为了校正主镜位置变化,本文提出了利用液压支撑对主镜相对镜室位置进行实时控制,实现对主镜稳像的方法。利用实验室现有的1.23mSiC主镜为监测目标搭建了测试系统,设计了基于6个位移传感器的位置监测系统。在未启用和启用液压稳像技术两种状态下,测试了主镜位置变化,并对主镜位置进行解算,试验结果表明液压支撑技术有确实的稳像效果。当镜室转动40°时,未稳像的主镜其X向平移变化为150μm,绕X轴转角为2.5"。采用液压稳像后,X向平移变化减小为3μm而绕X轴转角减小为0.4"。测试结果表明,基于液压支撑的主镜稳像技术可以实现对主镜位置的实时检测和控制。

The pitching rotation of a telescope will cause the relative displacement between a primary mirror and its cell,and the displacement will influence on the stabilizing image of a telescope.To correct the relative displacement of the primary mirror,a method for stabilizing images of the primary mirror was proposed based on a hydraulic support to control the displacement between primary mirror and cell.A 1.23 mSiC mirror in our lab was used to complete the online measuring experiment and a mirror position measuring system with 6 Line Variable Differential Transformer（LVDT）was established.Under two cases with or without mage stabilizing technologies based on hydraulic support,the displacement between mirror and cell was measured,and the 5 freedom of mirror was computed by using the measured data from sensors.Experimental results indicate that the proposed technology based on hydraulic support has excellent stabilizing image ability.Under the case without the image stabilization technology,the mirror displacement of Z direction is about 150μm and the angle around X axis is 2.5″when the rotation angle of mirror is 40°.However,the X displacement has reduced to 3μm and the angle reduced to 0.4″when this technology is conducted.It concludes that the stabilizing image technology based on hydraulic support can implement the determination and control of primary mirror position in real time.