月基极紫外相机跟踪转台设计与刚度分析

Design and stiffness analysis of tracking platform for lunar EUV camera

为了满足登月的任务要求,需要对极紫外相机的刚度进行优化设计与深入分析。二维跟踪转台是影响整机力学特性的关键部件,对影响其刚度特性的U形支架、轴系、蜗轮蜗杆传动机构进行了优化设计。为了准确评估二维转台的力学特性,考虑轴系与蜗轮副的间隙,采用间隙元理论代替耦合点约束建模分析,其基频为31.1 Hz。对力学模拟样机的力学特征扫描试验表明EUVC的特征频率为28.8 Hz,二者非常接近,因此采用间隙接触单元建模更能真实的模拟二维转台。通过整机正弦和随机力学振动试验表明,在保证跟踪转台机构正常运转和尺寸、重量约束的前提下,各环节的刚度设计合理,极紫外相机及二维跟踪转台基频特性及抗力学特性满足嫦娥探月工程的任务要求。

In order to meet the requirements for extreme ultraviolet camera （ EUVC ） in lunar landing task, it is neces- sary to implement the optimum design and deep analysis for the stiffness of the Extreme Ultraviolet Camera. The two- axis tracking platform is the key component that influences the mechanical characteristics of the camera. The optimum design of the U-shape supporter, the shafting and the worm gearing mechanism that influence the stiffness of the cam- era is carried out. To accurately evaluate the mechanical characteristics of the tracking platform, finite element model is applied, which adopts the gap element theory to replace the coupling point restriction modeling analysis;and the calculated natural frequency is 31.1 Hz,which is close to the EUVC characteristic frequency of 28.8 Hz from the vi- bration test result. Therefore, the gap element modeling can truly describe the 2-axis tracking platform. The sine and random vibration tests show that the stiffness design of the elements is reasonable ; the natural frequency characteristic and mechanical characteristic of the EUVC and two-axis tracking platform meet the requirements of the project of Chang E engineering, and the constraints for the size, weight and normal operation of the tracking platform are also guaranteed.