基于有向图的零件容差建模方法

Tolerance modeling approach to part based on directed graph

为了实现用计算机表示零件几何形状和尺寸变动的基准、变动方向和变动量的要求,提出了一种基于有向图的容差建模方法。该方法采用一个五元组来表示容差元:定义零件的参考坐标系和零件中与几何形状和尺寸相关的关键特征;采用图的有向边描述关键特征之间的容差关系;采用单位向量表示容差变动方向,实现容差元的有向图表示;基于图的和运算实现了对所有容差元模型求和,从而构建了零件容差模型。最后,给出了实例验证,并开发了与CATIA集成的容差建模功能模块。

In order to represent benchmark, fluctuation trend and fluctuation value of geometric shape ＆ dimension of component, a tolerance modeling approach based on directed graph was presented. A 5- tuple was used to represent recta-tolerance. The construction process of tolerance model was as following： firstly defining the reference frame and Key Features （KFs） related to geometric shape ＆ dimension, then describing tolerance relationship between KFs by directed arc of graph and a unit-vector was utilized to represent fluctuation trend of tolerance. All recta-tolerance models were set up based on directed graph. Then the tolerance model was constructed based on sum operation about graph for all recta-tolerance models. And a tolerance modeling system integrating with CATIA V5 was developed. Finally, the approach was validated by an example.