【摘要】 针对空间相机二维指向机构中碳化硅(SiC)平面反射镜的轻量化与刚度提升需求，提出了一种基于半封闭背板结构的创新设计方案。通过构建背部半封闭拓扑构型并用其替代传统开放结构，结合工艺孔尺寸调控实现了刚度提升。建立了指向镜的有限元模型，并将三种设计方案进行了对比。仿真结果表明，方案2在保证面形精度指标的前提下，质量由12.8 kg降至10.7 kg (降幅为16.4%),一阶固有频率由730 Hz提高到1528 Hz (增幅为109%),刚度质量比提高1.5倍，性能指标显著优于传统开放结构(方案1)和大孔径方案(方案3)。优化后的指向镜通过了正弦振动试验，面形精度的均方根(Root Mean Square, RMS)值提高了一倍，由0.073λ提升至0.036λ(λ=632.8 nm)。本研究提出的半封闭背板设计突破了传统轻量化结构的刚度局限，为其他空间反射镜设计提供了新方法。更多还原

【Abstract】 Aiming at the requirements of lightweight and stiffness improvement of silicon carbide(SiC) plane mirror in the two-dimensional pointing mechanism of space camera, an innovative design scheme based on semi-closed backplate structure was proposed. By constructing a semi-closed topological configuration on the back and replacing the traditional open structure with it, the stiffness was improved by combining the control of the process hole size. The finite element model of the pointing mirror was established, and three design schemes were compared. The simulation results show that, under the premise of ensuring the surface shape accuracy index, the mass of scheme 2 was reduced from 12.8 kg to 10.7 kg(a decrease of 16.4%), the first-order natural frequency was increased from 730 Hz to 1528 Hz(an increase of 109%), and the stiffness-to-mass ratio was increased by 1.5 times. The performance index was significantly better than that of the traditional open structure(scheme 1) and the large aperture scheme(scheme 3). The optimized pointing mirror passed the sinusoidal vibration test, and the root mean square(RMS) value of the surface shape accuracy was doubled from 0.073λ to 0.036λ(λ=632.8 nm). The semi-closed backplane design proposed in this study breaks through the stiffness limitations of traditional lightweight structures and provides a new approach for the design of other space mirrors.更多还原