大口径望远镜主镜位置控制系统设计

Design of Primary-Mirror Position Control System in Large Telescope

为了满足4 m大口径望远镜镜面成像对主镜位置的高精度需求,介绍了采用电机驱动浮动液压支撑方式的主镜位置控制系统设计方法。介绍了主镜位置控制系统的构成并建立了各结构的数学模型;基于线性扩张观测器和一阶动态滑模控制方法,设计了主镜位置控制器;对该控制系统进行了仿真验证。结果显示:在俯仰轴以1(°)·s-1的速度匀速运动的情况下,每个支撑区域的跟踪误差最大值小于0.5μm;在俯仰轴正弦引导情况下,跟踪误差最大值为1μm,明显优于传统的比例积分控制的13μm跟踪误差,满足4 m望远镜主镜位置控制系统的设计要求。该研究为大口径望远镜主镜位置控制系统设计提供了一定的参考。

A design method of a primary-mirror position control system based on motor-driven hydraulic support is proposed to meet the high precision requirements of the primary mirror position in mirror imaging of a 4 m large telescope.Firstly,the composition of the primary-mirror position control system is introduced,and the mathematical model of each structure is established.Furthermore,a primary-mirror position controller is designed based on the first-order dynamic sliding mode control and a linearly extended observer.Finally,the system is simulated.The results show that the maximum tracking error of each support area is less than 0.5μm when the tilt axis moves at a uniform speed of 1(°)·s-1.Besides,in the case of sinusoidal guidance of the tilt axis,the maximum tracking error is 1μm,which is better than the tracking error(13μm)of the traditional proportional-integral control.The results satisfy the design requirements of the proposed system in the 4 m large telescope,providing a reference for the design of a primary-mirror position control system in a large telescope.