平面桁架构建的定日镜面形支撑结构优化及实验

针对反射面成型的复杂影响因素，提出平面桁架构建的定日镜面形支撑结构优化技术路线. 利用模拟仿真、数值计算和优化算法等方法，解析20 m²定日镜面形定义技术路线的4个组成环节：面形规格及宽高比、上弦杆的截面矩、平面桁架组间距的最优值、机加工中工艺控制要点的量化. 试制小型定日镜进行实验，分析光斑形状和能流密度分布特性，并与理想球面形光斑比较，两者的拟合优度大于0.98. 实验结果表明，当反射镜宽高比取1.2，上弦杆截面矩取40 000 mm⁴，桁架组间距取950 mm，上弦杆和斜杆的开孔公差小于0.9 mm时，反射面形的质量提升. 研究从原理和实践上证明了该优化技术路线的可行性.

Optimization and experiment of heliostat surface shape bracing structure based on plane truss

A technical route of the optimization of heliostat surface bracing structure based on plane truss was proposed because of the complex influence factors of reflector forming. Four key points that included the surface width/height ratio of the 20 m² heliostat, the cross-section moment of the upper chord, the optimization of the space between the plane truss groups and the quantification of control points in machining stage was analyzed, by simulation, numerical calculation and optimization algorithm. Trial-manufacture and field experiment was conducted that the distribution characteristics of spot sharp and energy flux were the same as that of ideal spherical shape, and their goodness of fit was greater than 0.98. The experimental results showed that when the surface width/height ratios set to 1.2, the cross-section moment of the upper chord set to 40 000 mm⁴, the truss groups spacing set to 950 mm, the tolerance of upper chord and inclined rod was less than 0.9 mm, and the reflective surface quality was improved. The feasibility of optimization technique route was proved by the principle and practice.