以减轻重量为目标的索网桁架式可展开太空天线结构的优化设计

Optimal design of cable-truss deployable spaceborne antennas for structure weight reduction

针对索网桁架式可展开天线的结构特点和性能要求,对其结构初始设计进行了优化研究。选取天线的桁架单元壁厚和索单元半径为设计变量,并对不同类型的设计变量进行了合理的归并,继而以结构重量为优化目标,以表面精度和基频为约束条件,建立了优化设计数学模型。考虑到索网结构有限元分析给计算带来的非线性和复杂性,使用序列二次规划法对模型求解,并给出了相关动力特性的敏度分析。通过算例分析可知,采用上述优化计算方法可以在保证天线工作性能的前提下有效地降低结构的重量,同时由优化迭代过程中约束函数值的变化情况可知,在一定范围内减小桁架单元壁厚和增大索单元半径,可以有效地提高天线表面精度和改善结构动力性能。

In order to meet the requirements of the performance of space cable-truss deployable antennas, the initial antenna structure design was optimized according to their structural characteristics. In the optimization, the wall thickness of truss and the radius of cable were chosen as the design variables, and they were merged properly to simplify the calculation. Then the optimal mathematical model was established with the minimum structural weight being the optimization goal and the surface accuracy and natural frequency being the constrains. In consideration of the difficulty in solving such a complex model due to the geometric nonlinearity in calculation, a sequential quadratic programming method was used, and the sensitivity analysis of frequency was given at the same time. The optimal result shows the validity and effectiveness of the proposed method and model. Moreover, it is clear from the iterative process that the antenna performance can be improved by reducing the radius of cable and increasing the wall thickness of truss properly.