曲率信息驱动的飞机蒙皮装配变形建模方法

Deformation modeling method of aircraft skin in assembly driven by curvature information

在飞机零组件装配过程中,蒙皮的变形严重影响产品的形面精度质量。面向蒙皮装配变形的监测需求,提出一种由曲线到曲面的建模方法,将多条粘有正交光纤光栅的形状记忆合金丝安装于蒙皮表面,通过实验标定方法实现光栅波长偏移量到合金丝曲线曲率的准确转换,再将曲率信息转化为曲线点的空间坐标信息,最后对每条曲线的坐标系进行配准,完成壁板蒙皮装配形状的建模。仿真和实验表明,提出的方法可以实现蒙皮在装配场景下的弯曲形态感知。实验以光学仪器C-Track的测量结果为基准,模型中蒙皮特征点对距离的绝对误差平均值和最大值分别为3.58 mm和8.67 mm,相对误差平均值和最大值分别为0.70%和1.94%。同时,还对曲线建模误差的变化规律进行了分析:数学论证和仿真结果均表明误差随曲率采样点间隔的变化呈现递增趋势且递增速度与曲线的挠率和曲率相关;并还指出误差随点位递推次序的变化并非一定呈现单增趋势,其与曲率的单调性等因素相关。

In the process of aircraft components assembly,the deformation of skin has vital influence on shape accuracy of product.Faced with the requirement of monitoring such deformation,an approach of surface modeling based on curve reconstruction was proposed.Attaching the shape memory alloy substrate with orthogonal fiber Bragg grating sensors to the skin and realizing the transition from curvature information to the positional information of the points on curves by calibration,the skin modeling could be completed.The results of simulation and experiment showed that the approach presented realized the perception of the skin’s bending form in the scene of assembly.Based on the measuring result of the C-Track,the mean and maximum absolute errors of the distances between pair of the feature points on model were 3.58mm and 8.67 mm respectively,while the mean and maximum relative errors were 0.70%and 1.94%respectively.In addition,the variation of the curve modeling error was analyzed.The mathematical proof and simulation results showed that the variation with interval of measuring points was ascending and the increasing rate was related to the curvature and torsion.Moreover,the variation with recursive order was not necessarily ascending,it had correlations with factors such as monotonicity of curvature.