雷达罩产品外型的反演算法

REVERSE ALGORITHM FOR OUTER CONTOUR OF AIRCRAFT RADOME

宽频带雷达罩设计经常从气动外型通过电性能设计得到蜂窝夹层厚度为变厚度的雷达罩的内型。加工后雷达罩成型阳模往往与产品的内型相比产生偏差,从而导致电厚度的不准确。从有偏差的阳模外型出发,通过雷达罩内型面点处的法线、位置角度及相关点附近的厚度函数,形成将内型面点处的法线转换成外型面对应点处的法线的转换矩阵,通过反演循环逐步逼近外表面的数据点。随着循环的进行,转换矩阵的数值及相应点的坐标数值将逐步稳定,当相邻两次矩阵及坐标值变化满足精度时,则循环终止。利用循环终止时的外型面点的坐标、法线及变厚度蜂窝的厚度公式,便可得到夹层结构雷达罩的内外层蜂窝外型面。这样,在模具有偏差时,也能得到符合电厚度要求的雷达罩结构。

The design of broadband radomes often starts from aerodynamic contour to make electrical perform- ance calculation that ends with obtaining of an optimized radome structure with a changing honeycomb layer thick- ness on basis of three dimensional surfaces. The male mold used to manufacture radome often has tolerances that lead to inaccuracy of the electrical thickness for the radome wall structure. This paper, by using reverse iteration al- gorithm, obtains accurate outer contour by using point coordinates and its normal vector of the finished male mold, angle positions of points and thickness formulation of radome. As reverse iteration goes on, point coordinates on out- er surface of radome as well as the transformation matrix that changes inner real normal vector to normal vector of outer surface converges. When accuracies are achieved, reverse iteration ends. Using obtained outer surface coordi- nates forme d its normal vector as well as the thickness formulation, the outer surface of the two layers of honeycomb can be With this method, precise electrical performances can be achieved even when the shaping mold has discrep- ancies and tolerancies.