为降低对地观测小卫星单机安装点加速度响应均方根值, 提出了一种使加速度响应均方根值最小化的微小卫星主承力结构拓扑优化方法。首先对整星方案进行了有限元分析, 分析显示整星Z向某些单机安装点的随机振动加速度响应均方根值过大。对系统进行了灵敏度分析, 确定了卫星主承力结构底板是影响随机振动加速度响应均方根值大小的关键因素。以卫星单机安装点的加速度响应均方根值为目标函数, 以体积作为优化的约束条件, 应用连续体结构拓扑优化思想对卫星有限元模型进行拓扑优化设计, 得到了一种单机安装点加速度响应均方根值满足指标要求的卫星主承力结构。最后, 通过有限元分析与振动试验, 证明了本文所设计的小卫星主承力结构力学性能参数均满足设计要求, 其中整星的星敏感器、蓄电池、电源控制器等关键器件安装点的加速度响应均方根值相比优化前分别降低了23 3%、10 6%、11.3%, 得到的结果验证了本文优化方法的有效性。

To decrease the single installation point acceleration response RMS(Root Mean Square) of a micro-satellite for earth observation, this paper presents a topology optimization method for satellite primary load bearing structure to minimize the acceleration response RMS. Firstly, the design scheme of the entire satellite is analyzed by finite element simulation. The results suggest that the acceleration response RMSs of some component installation points are too large and failed to meet the design requirements. By sensitivity analysis, it points out that the backplane is a key element for the acceleration response RMS of Gaussian random vibration. By adopting the method of topology optimization for a continuous body, the satellite model is optimized and a new model that fully meets the design requirements is obtained by taking the acceleration response RMS as an objective function and the volume as a restrict condition. Finally, both the finite element simulation and Gaussian random vibration are performed. It indicates that the parameters of new satellite primary load bearing structure meet design requirements, and among them, the acceleration response RMSs of some key component installation points like star sensors, storage battery and source controllers have reduced at least 23.3%, 10.6%, 11.3%, respectively. These results verify the feasibility and effectiveness of the proposed optimized topology.