飞机结构件槽腔内面间最短距离计算算法

Algorithm for calculating the shortest distance between the inner surfaces of the pocket of an aircraft structure

在飞机结构件数控加工自动编程系统的开发过程中,由于零件的特征层面的工艺性缺陷,特别是槽腔内面间的最短距离过小,容易导致零件加工复杂、成本过高甚至无法加工。目前针对该模型问题主要采用人工检查的方式,不仅效率低且易出错。针对具有复杂形状,并且包含开闭角、内陷等复杂特征的飞机结构件槽腔,其侧壁面间最短距离无法直接获取的问题,提出飞机结构件槽腔内面间最短距离计算算法。首先给出槽腔以及与距离相关的术语定义,接着在特征几何参数提取的基础上,将侧壁面间最短距离计算转化为线线间最短距离计算,并根据槽特征的几何特性提出线线距离有效性判断准则以简化计算,求得槽特征内侧壁面间最短距离。最后,以某飞机结构件模型为例,验证了该算法的可行性和有效性。

In the development process of the automatic programming system for computer numerical control(CNC)machining of aircraft structural parts,the process defects of the part feature,especially the shortest distance between the inner surfaces of the pockets being too small,was likely to complicate the processing of parts,incur high cost,or even render the processing impossible.At present,this model problem was mainly inspected manually,which was inefficient and error-prone.For the pockets of aircraft structural parts with complex shapes and such complex features as open and closed angles and indentations,it was difficult to determine the shortest distance between side walls.Based on the extraction of feature geometric parameters,the calculation of the shortest distance between side walls was converted to the computation of the shortest distance between lines.The validity rules of the distance calculation between lines were presented to simplify the calculation according to geometric features of the pocket’s characteristics,and the shortest distance between inner wall surfaces of pocket features was obtained.Finally,an aircraft structure model is taken as an example to verify the feasibility and effectiveness of the algorithm.