临近空间望远镜次镜优化设计

根据临近空间球载望远镜高力热稳定性、高性能的要求,对其次镜组件进行优化设计。临近空间球载望远镜虽然没有火箭发射力学环境严苛,但是其独特的飞行过程受到温度变化、加速度等影响,同时由气球搭载升空,质量要求较为严格。相比于传统反射镜设计方法,采用实体优化和基结构优化相结合的方法,集成优化对镜体进行设计,引入综合评价因子优化次镜综合性能,最终次镜组件性能良好,说明优化方法有效。通过有限元仿真分析得次镜组件在重力和±3℃均匀温变工况下刚体位移小于3μm,面形精度优于λ/50,在0.02 mm装配误差下面形精度优于1 nm。次镜组件一阶频率为203.8 Hz,10 g加速度应力响应(35.4 MPa)远小于材料屈服应力。采用该方法优化可获得高力热稳定性、高性能的次镜组件。

Optimization design of secondary mirror for near space telescope

According to the requirements of high force-thermal stability and high performance of the near space ball-borne telescope, the design of the secondary mirror assembly was optimized. Although the near-space ball-borne telescope was not as harsh as the rocket launching mechanical environment, its unique flight process was affected by temperature changes and acceleration. At the same time, it had a strict quality requirement due to carry with balloon. Compared with the traditional mirror design method, the method of combining entity optimization and base structure optimization, integrated optimization was used to design the mirror, and introduced comprehensive evaluation factors to optimize the overall performance of the secondary mirror. The performance of the final secondary mirror assembly is good, indicating that the optimization method is effective. Through finite element simulation analysis, it is obtained that the secondary mirror assembly has a rigid body displacement of less than 3 μm, a surface accuracy better than λ/50 under the condition of gravity and temperature change of ±3 ℃. Under 0.02 mm assembly error, the shape accuracy is better than 1 nm. The first-order frequency of the secondary mirror assembly is 203.8 Hz. The 10 g acceleration stress response (35.4 MPa) is far less than the material yield stress. Using this method to optimize can obtain high force-thermal stability, high performance secondary mirror assembly.