空间相机反射镜镜面面形处理

Surface figure treatment for mirrors of the space camera

镜面面形误差是空间相机反射镜的重要指标之一,对空间相机反射镜结构的设计及优化具有重要的指导意义。为分析空间相机反射镜在各种工况下的面形误差情况,以球面镜为例,对镜面面形误差的计算方法进行了研究。采用三种不同的球面拟合方法对变形后的反射镜镜面进行球面拟合,并计算得变形后反射镜镜面面形误差的RMS值和PV值。最后,通过计算实例对三种面形误差计算方法进行了比较,结果表明三种计算方法精度均满足空间相机反射镜镜面面形误差计算精度要求(优于1nm),综合考虑计算精度及效率,高斯-牛顿法为最佳计算方法。

Surface figure error is one of the most important indexes of the space camera s mirrors and a guiding index of the optimal design of the mirror＇s structure. In order to obtain the surface figure error of the mirrors in any load cases, surface figure treatment has been studied on with the spherical mirrors. First, three different methods for spherical fitting were carried out to fit a new spherical surface for deformed mirrors. Then, the RMS and PV were calculated for the deformed mirrors according to the newly fitted spherical surface. At last, the three methods were compared by an example, and the results indicate that the surface figure error precision in calculation （less than I nm） was satisfied with all the three methods, and the Gauss-Newton method was the best choice if precision and efficiency were comprehensively considered.