用于空间快速指向机构的轻量化反射镜研究

Research on Lightweight Mirrors for Space Fast Pointing Mechanisms

为了满足空间激光通信和激光雷达载荷中快速控制反射镜的使用需求,研制了一种轻量化SiC反射镜。首先,根据指向机构的使用工况和动力学响应要求,对反射镜结构的安装形式以及轻量化进行了优化设计;其次,通过有限元仿真分析,计算出反射镜的动态特性和安装使用中的面形变化,模拟出镀膜应力对反射镜面形的影响;最后,结合镀膜应力的产生机理和作用方式,在反射镜光学加工阶段预制面形补偿,解决了反射镜镀膜中面形退化问题。测试结果表明,反射镜在装配过程中的面形变化均方根(RMS)≤0.005λ(λ为波长,λ=632.8nm),反射镜安装后的最终面形变化RMS值为0.019λ,可以满足系统使用的指标要求。该反射镜的结构设计与分析流程以及镀膜加工方法可以应用到其他类似反射镜的设计与加工过程。

In order to meet the requirements of the fast steering mirror in space laser communication and Lidar payloads, a lightweight SiC mirror is developed. Firstly, according to the working conditions and dynamic response requirements of the pointing mechanism, the installation form and lightweight structure of the mirror are designed. Secondly, through the finite element simulation analysis, the dynamic characteristics of the mirror and the surface shape change in installation and operation are calculated, and the influence of coating stress on the reflection surface is simulated. Finally, combined with the generation mechanism and action mode of coating stress, the surface shape compensation is prefabricated in the optical processing stage, which solves the problem of surface shape degradation in the coating of the mirror. The test results show that the surface shape change root mean square(RMS) in the assembly process is less than 0.005λ, and the final surface shape change RMS after installation is 0.019λ, which can meet the system requirements. The structural design and analysis process of the mirror and the coating processing method can be applied to the design and processing of other similar mirrors.