多点支撑卸载的大口径天基空间相机兼容六足运动学支撑结构的重力卸载关键技术研究

According to the ground alignment and testing requirements for large aperture and high stability space-based cameras, A gravity compensation scheme that The Multi-point Support Unloading of Large-aperture space-based camera is compatible with the hexapod Kinematic mounts was proposed. The mathematical model of equivalent compliances and frequency of Hexapod support structure is established to complete the design of the hexapod kinematic mounts with certain attenuation rate and stiffness requirement. The optimal gravity compensation method for large-aperture space-based camera is determined to research on the gravity compensation methods based on the position closed-loop and the force closed-loop . Based on the research of establishing the equivalent stiffness model of space camera, the sensitivity analysis of gravity compensation point, the decoupling conditions of the axial compensation and radial compensation, and the optimization of the unloading force, a method of optimizing the position of gravity compensation point based on the sensitivity analysis is summarized.The prototype was developed to verify the correctness of the theoretical analysis and the finite element analysis.This project aims to propose a new gravity compensation scheme for the large-aperture space-based camera and an optimization method for gravity compensation point position, which can provide reference for the gravity compensation of other similar cameras.

针对大口径、高稳定性天基空间相机的地面装调及测试需求，提出了多点支撑卸载的大口径天基空间相机兼容六足运动学支撑结构的重力卸载方案。建立六足支撑结构的等效柔度及频率数学模型，完成特定衰减倍率及刚度需求的六足运动学支撑结构设计；开展基于位置闭环与力闭环的重力卸载方法研究，确定大口径天基空间相机的最优卸载方法；通过建立空间相机的等效刚度模型、卸载点灵敏度分析、轴向卸载和径向卸载的解耦及卸载力的优化等方面的研究，总结了一种基于灵敏度分析的重力卸载点位置优化方法；研制原理样机进行相关的试验，以验证理论分析、有限元的正确性。本项目旨在提出一种新的大口径空间相机的重力卸载方案及卸载点位置优化方法，为其他同类相机的重力卸载提供借鉴。

针对大口径、高稳定性空间相机的地面装调及测试需求，提出了多点支撑卸载的大口径天基空间相机兼容六足运动学支撑结构的重力卸载方案。详细分析了六足运动学支撑结构的组成、设计原则及自由度。根据万向柔性铰链的柔度公式，推导了柔性支杆在X、Y、Z轴方向等效柔度Cx、Cy 和 Cz 的解析式。建立了六足运动学支撑结构与空间相机的刚度数学模型。完成满足特定衰减倍率及刚度要求的六足运动学支撑结构设计，其最优设计参数r取值为12.5mm，并进行仿真验证，结果表明：解析式结果与理论结果基本一致，误差为5.3%。经基于力闭环与位置闭环的重力卸载方法对比分析，得到基于力闭环的卸载装置施加卸载力为最优卸载方法的结论。完成六足运动学支撑结构的受力分析及整机变形机理分析。确定轴向多点卸载和径向多点卸载的解耦条件。提出一种基于灵敏度分析的卸载力位置及大小的优化方法，得到在研光学载荷的最优卸载方案为14个轴向卸载力及6个径向卸载力。进行六足运动学支撑结构衰减倍率测试试验及大口径空间相机重力卸载试验，试验结果表明：（1）六足运动学支撑结构满足10倍衰减倍率的指标要求；（2）通过重力卸载，主、三镜模拟件绕Y轴的相对倾角变化由112.31"变化到-0.8"，基板改造件平面度PV值由0.841mm变化到0.035mm，证明了大口径空间相机重力卸载方案的可行性。本项目提出的大口径空间相机重力卸载方案及卸载力优化方法为其他同类相机的地面装调及测试提供借鉴。

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