为满足机载摆扫式光谱仪在25 Hz扫描频率下工作的要求, 设计了具有三面反射镜的摆镜结构。首先, 计算镜面反射区域面积与旋转轴偏离量的关系, 通过比较摆镜布置不同数目反射镜时的性能, 设计了围绕旋转轴布置三面反射镜的摆镜结构形式, 通过600 r/min的转速即可完成每分钟1 800次的高频摆扫; 同时采用匀速摆扫的运动方式, 降低了摆镜的控制难度, 提高了系统的稳定性。然后, 采用拓扑优化、集成优化等方法对摆镜结构进行了优化, 摆镜最终质量为5.28 kg, 轻量化率达到58%。最后, 通过有限元仿真计算得到: 摆镜在机载平台600 r/min转速离心力与1 g重力的作用下, 面型精度RMS值优于λ/20, 基频达到1 199 Hz, 具有较高的力学稳定性, 满足机载摆扫式光谱仪的高扫描频率要求。

Aiming at fulfilling the requirement of 25 Hz high scanning frequency of the airborne whiskbroom scanning spectrometer, a swing mirror with three reflectors is designed. Firstly, by revealing the relationship between the reflection area and the deviation of the rotation axis and comparing performance of several swing mirrors with the different numbers of reflectors. The arrangement of three reflectors around the rotation axis of swing mirror was adopted. Thus rotating at a speed of 600 r/min the mirror was able to achieve 1 800 scans within a single minute. At the same time, the swing mirror used uniform rotation to reduce the difficulty in controlling and improve the stability of the sweep-scanning system. Through topology optimization and integrated optimization, the weight of the swing mirror was reduced to 5.28 kg and the lightweight ratio was 58%. Finally, calculated by the finite element simulation, the RMS of the reflector was better than λ/20 in 1 g gravity and centrifugal force at 600 r/min rotate speed environment and the fundamental frequency is 1 199 Hz. This verifies that the swing mirror is of high mechanical stability. It can satisfy the higher scanning frequency requirement of airborne whiskbroom scanning spectrometer.