太空环境下考虑展开臂铰链间隙的大型网状天线电性能稳健性研究

For the influence of extreme space temperature, microgravity effect and joint clearances, a locked deployable arm of a large-scale mesh antenna still have a small range of motion, which will degrade the EM performance such as distribution of the antenna gain and beam pointing accuracy et.al, and even lead to failure of space missions. Since in the space environment, the clearance size is related to the environment temperature and the relative position of the shaft and sleeve of the joints is random, application of the existent clearance model is limited. Moreover, influence mechanism of the clearances on the antenna EM performance is still not clear and robustness study of the EM performance considering the clearance effect is a key problem to be solved. To address these problems, first, an inner-contact-beam model that considers the size and contact status of the clearance is proposed to model the clearance. Then nonlinear relationship between the clearance and the EM performance is obtained through the deformed reflector shape. Second, parameters that represent the clearance size and randomness of the contact status are proposed, and relationship of the EM performance and the parameters are established based on interval analysis. Base on which intervals of the far-field pattern can be calculated, and indexes can be obtained from the far-field pattern to predict the EM performance. Third, considering the influence of the space environment and the clearances, a robust optimization model for large-scale mesh antennas is presented and solved to obtain the design parameters that can improve the robustness of the on-orbit EM performance. Finally, experiments are carried out to correct and verify the presented theoretical models and design methods, and provide useful guidance and reference for engineering practices.

受太空极端温度、微重力环境及间隙的影响，大型网状天线展开臂关节锁定后依然具有小幅运动范围，致使天线增益分布和波束指向等电性能恶化，甚至导致航天任务失败。由于太空环境中，运动副间隙大小与温度相关，且其轴与轴套的相对位置具有随机性，现有间隙模型应用受限，且间隙对天线电性能的影响机理尚不明晰，考虑间隙的电性能稳健性问题亟待研究。为解决上述问题，首先，提出一种能表征间隙大小和接触状态的内接触梁单元模型进行间隙建模，并以反射面位形为媒介，研究间隙状态与电性能间的非线性关系。其次，提取表征间隙大小和随机性的参数，建立电性能与间隙参数间的区间关系模型，获得极端温度工况下远场方向图的变化区间，从中提取电性能指标以预测电性能。再次，建立考虑空间环境与间隙影响的电性能稳健设计数学模型并求解之，以获取提高天线电性能稳健性的设计参数。最后，通过实验修改和验证提出的理论模型和设计方法，为工程实践提供指导和参考依据。

受太空极端温度、微重力环境及间隙的影响，大型网状天线展开臂关节锁定后依然具有小幅运动范围，致使天线增益分布和波束指向等电性能恶化，甚至导致航天任务失败。为解决该问题，本项目研究了太空环境下间隙大小和随机性对星载大型网状可展开天线指向误差和增益的影响；建立了表征间隙大小和随机性的区间模型，开展天线远场方向图的区间分析研究，获取电性能指标的区间范围，预测天线电性能的恶化程度；开展了影响电性能的关键结构参数的研究，确定展开关节间隙、关节关键结构尺寸和展开臂预安装角等参数为设计变量，建立了电性能稳健优化模型，开展了考虑间隙影响的天线电性能稳健优化设计；通过两步走的实验测试方案，修改和验证了本研究提出的理论模型和设计方法。案例研究结果表明，本项目提出的理论和方法是可行且有效的，可以对间隙影响下的天线波束指向精度和增益变化区间进行有效预测，经稳健优化设计后天线的指向误差的稳健性提升幅度可达90%以上，且发现间隙对增益的影响幅度较小，而末端展开臂关节间隙对指向精度的影响最为剧烈，在生产过程中应着重控制其制造水平。本研究可为含间隙航天结构的设计与性能提升提供指导和参考依据。