星载三层赋形网状天线的机电集成设计及力热匹配机理研究

Large high-precision contoured beam mesh antennas are needed to support China's major strategic tasks such as manned spaceflight and earth observation. Mesh antennas belong to tensioned structures, but the ideal shaped reflectors designed from the electromagnetic performance are always concave-convex surfaces, which leads to that the concave-convex mesh reflector cannot be supported through the existing mesh antenna approaches. In addition, for the on-orbit antennas, the shape accuracy and electromagnetic performance of the antenna are easily affected by the thermal loads, but the current researches have not given an effective method to suppress the thermal deformation. To address these problems, first, based on the force balance characteristics of the mesh antenna, an innovative three-layer mesh antenna approach is proposed to support the concave-convex shaped mesh reflector. Second, the nonlinear relationship of the structural and electromagnetic performances is studied based on the integrated structural-electromagnetic analysis model. A multidisciplinary optimization model is also established to get the optimal shaped reflector and achieve the optimal comprehensive performance. Then, based on the mechanical-thermal matching mechanism of the cable-membrane-beam structure, a mathematical model of thermal insensitive design for mesh antennas is established to get the optimal structure parameters and achieve the precontrol of the on-orbit thermal deformation. Finally, experiments are carried out to revise and improve the proposed theoretical model and design method in this project, and provide theoretical guidance for the engineering application of the new generation contoured beam mesh antennas.

我国载人航天、对地观测等重大战略任务对大型高精度赋形波束网状天线提出了迫切需求。网状天线需要张拉成形，仅从电性能出发设计的理想赋形面通常为凹凸曲面，导致现有的二层网状天线结构无法支撑“凹凸”的赋形反射面；网状天线在轨应用时，空间热载荷会导致天线发生热变形，严重影响电性能，而现有研究尚未提出有效的热变形抑制方法。针对该问题，研究网状天线张拉结构的力平衡特性，提出新型三层赋形网状天线方案；建立网状天线的机电集成分析模型，揭示电性能与结构性能之间的非线性影响关系，构建赋形设计的多学科优化模型，获取赋形反射面形状和结构预张力参数，实现结构-电磁综合性能最优；揭示索-膜-梁组合张拉结构的力热匹配机理，建立网状天线热不敏感设计的数学模型，获取最优天线结构参数，实现在轨热变形的预控制，并研制实验验证系统，通过实验来修正和完善本项目提出的理论模型和设计方法，为新一代赋形网状天线的工程应用提供理论指导。

赋形网状可展开天线不仅具备抗干扰能力强、辐射能量利用率高的特点，而且其波束可准确覆盖指定的任何地图区域，具有巨大的军事和经济效益。赋形网状天线需要通过张拉成形，导致传统二层网状天线结构无法支撑“凹凸”的赋形网状反射面；网状天线在轨服役时，空间热载荷会导致网状反射面发生热变形，致使致电性能恶化，甚至导致航天任务失败。为解决该问题，本项目从网状天线的张拉平衡特性出发，提出了三层赋形网状天线新方案，实现了“凹凸”的赋形网状反射面的张拉平衡；建立了赋形网状天线的机电集成分析模型，揭示了天线电性能与结构预张力之间的数学关系；基于机电集成分析模型，构建了网状天线波束赋形设计的多学科优化模型，通过合理设计预张力参数，实现结构-电磁综合性能最优；并基于拓扑优化思想，提出了赋形网状反射面的最优拓扑构型设计方法，在满足电性能要求的条件下降低赋形网状天线的结构复杂度。在此基础上，建立了网状天线索-膜-梁结构的力热匹配模型，揭示了网状天线结构的力热匹配机理，并提出了网状天线的热不敏感设计方法，获取最优结构参数，预控制天线的在轨热变形。研究表明，基于机电集成的波束赋形设计方法可以实现赋形网状天线的结构-电磁综合性能最优，不仅满足了远场电性能指标，而且整体索网结构的张力均匀性较好，工程易实现；热不敏感设计方法可以获取最优天线结构参数，使得天线结构在热载荷作用下内力协调变化，天线结构的热变形幅值降低了一个数量级，在不增加天线系统复杂度和成本的条件下实现了天线在轨热变形的预控制。本研究建立了赋形网状天线机电集成设计和热变形预控制的理论基础，可为赋形网状天线的设计和工程应用提供理论参考与指导。