动量轮诱导的卫星地面微振动特性研究以及在轨仿真分析

Study on Micro-vibration of Satellite Induced by Momentum Wheels and On-orbit Simulation Analysis

目的探索整星微振动传递特性及其影响因素,为降低或控制微振动对卫星相机成像质量的影响提供手段。方法利用某卫星结构,在卫星固支与悬吊两种边界状态下,开展不同动量轮转动组合状态的地面微振动环境试验。根据试验数据,分析从振动源到相机的传递比、卫星固支与悬吊的差异、卫星结构与转动部件分别对振动谱的贡献。利用卫星有限元模型,通过修改地面模型、添加组件等方式使其符合在轨状态,从而开展在轨微振动仿真分析。结果得到了动量轮各工作状态下的星上微振动加速度环境数据。根据数据分析结果,卫星边界固支与悬吊都附加了低频的振动,而星上微振动在动量轮转动频率外更包含了卫星结构的耦合振动。从振动源到相机的微振动传递都具有衰减特性,传递比为0.03~0.475。微振动仿真分析给出了相机微振动转角和影响。结论相机的微振动主要取决于最大扰动的动量轮。从振动源到相机的微振动传递中,传递界面的阻尼对微振传递比影响较大,其次为距离的影响。根据此卫星微振动传递特性提出了的微振动抑制手段有效降低了相机处的微振动大小。在轨状态仿真结果显示太阳翼低频振动耦合引起相机约0.1像素的振动。

Objective To study the micro-vibration transfer characteristics and influencing factors so as to provide means to reduce and control the influence of micro-vibration on the imaging quality of satellite camera. Methods Taking advantage of satellite structure, the micro-vibration environment tests were carried out with different rotating combinations of momentum wheels under the fixed boundary and the suspended boundary conditions. Based on the experimental data, the contributions of the transfer ratios from the wheels to the camera, the differences between fixed boundary and suspended boundary, satellite structure and momentum components on vibration spectrum were analyzed. The satellite finite element model was made to conform to the on-orbit status by modifying the ground model and adding the panel so as to conduct on-orbit micro-vibration simulations. Results The on-board micro-vibration acceleration data were obtained under each working status of the momentum wheels. Based on the obtained acceleration data, the fixed boundary and the suspended boundary conditions were both added with the low frequency vibrations, and the on-board micro-vibration included the coupled vibration besides the rotating frequency of the momentum wheels. The micro-vibration transmissions were all in decay with ratios of 0.03-0.475. The micro-vibration simulation analysis provided the camera micro-vibration angle and the influence. Conclusion The micro-vibration of camera mainly depended on the momentum wheel with the highest disturbance. The transfer of micro-vibration from the vibration source to the camera was mainly affected by the interface damping, secondly by the distance. The proposed vibration reduction method based on this transfer characteristic effectively reduced the micro-vibration amplitude of the camera. The on-orbit micro-vibration simulation analysis showed a 0.1 pixel vibration of the camera caused by coupled low frequency vibration of solar wing.