【作者】 李智；

【导师】 曹鸿钧；

【作者基本信息】 西安电子科技大学 ， 机械制造及其自动化， 2014， 硕士

【摘要】 卡氏天线是精密的机电一体化系统，副面位置误差将直接影响天线的电性能，必须在设计时对其加以有效控制。副面位置误差受多种结构因素的影响，如构件尺寸、材料属性以及环境荷载等。在结构设计阶段，这些结构因素往往带有一定程度的不确定性。不确定因素会引起天线电性能的波动，降低设计方案的稳健性。为此，本文在国家自然科学基金支持下，着重研究了考虑副面位置误差的卡氏天线稳健优化设计问题，主要工作如下：1.基于几何光学法，总结并研究了考虑副面位置误差的卡氏天线电性能计算程序和方法。给出了考虑副面位置误差的机电综合仿真实现方案，在此基础上编写了相应的机电综合仿真程序。该程序通过读取有限元分析的变形信息，可计算天线的远场方向图、增益损失、指向误差、副瓣电平和波瓣宽度等电性能指标。对某8m天线进行了机电综合仿真，验证了程序的正确性。2.以背架和副面撑腿尺寸为设计变量，以增益损失为目标函数，以结构体积和电性能指标为约束函数，建立了考虑副面位置误差的卡氏天线结构优化设计模型，并对某8m天线进行了案例验证。3.基于稳健优化的敏感区域法，综合考虑卡氏天线的面板厚度以及杆件、反射面板材料的密度和弹性模量等参量的不确定性，建立了考虑副面位置误差的稳健优化模型。该模型是一个二级优化问题。为了简化求解过程，采用RBF响应面法建立了下层优化问题的替代模型。对某8m卡氏天线进行了稳健优化设计，有效减小了其电性能的波动程度。更多还原

【Abstract】 Cassegrain antenna is a kind of sophisticated mechatronic structure. Subreflectorposition errors of the antenna may greatly reduce it’s performances and must becontroled in the design stage. The position errors are affected by many structuralfactors,such as component sizes, material properties and loadings, most of which areuncertain to designers. These uncertain factors may produce adverse fluctuations on thefinal electromagnetic performances and must be considered quantitatively to improvethe robustness of a design scheme. In this paper, under the support of National NaturalScience Foundation of China, the robust design problem of Cassegrain antenna isinvestigated with consideration of the subreflector defocuses.The main works are asfollows:1. The existing theory and techanics for analyzing electromagnetic performancesbased on the geometric optics method for Cassegrain antennas with subreflectordisplacements are summarized and investigated. An integrated structral-electromagneticsimulation scheme is given and a correponding prototype program is composed. Thisprogram reads deformation information from finite element software, and calculatesradiation performances such as far field pattern, gain reduction, side lobe levels,pointing error and beam width etc.. An8-meter antenna is analysed by using theprogram as a demonstration.2. Considering subreflector deformations, an optimization model for Cassegrainanttenas is constructed. The objective is to minimize gain reduction while satisfyingcostrains such as structural volum, side lobe levels and pointing error. The componentsizes of backup structure and the subreflector supporting legs are taken as designvariables. The8-meter antenna is optimized with good results.3. Based on the sensitivity region method, a robust optimization model isconstructed considering uncertainties on parameters such as panel thinkness, materialdensities and elastic modulus. The model is a bilevel optimization problem. To solve itefficiently, the optimal objective values of the sub-level problem are interpolated by anRBF model. The whole solution process is simplified considerably. The robustoptimization results of the8-meter antenna show that the sensitivity of the radiationperformances with respect to uncertain parameters can be reduced effectively by theproposed model and method.更多还原