钣金件中匹配孔的半径差及轴线重合度自动检查

摘 要：针对汽车钣金件中匹配孔的半径差及轴线重合度人工检查效率低、易遗漏等问题， 提出了钣金件中匹配孔的半径差及轴线重合度自动检查方法。首先将获得的 B-Rep 三维模型以 面壳封闭的方法拓扑分解为面基本单元；其次根据圆柱面具有 2 条半圆弧线和 2 条直线的特征 对圆柱面进行筛选，并以其为基本单元对圆孔和槽孔进行提取；然后分别获取圆孔和槽孔的半 径及轴线，并利用点到点和点到线距离方法，根据孔匹配原理对匹配孔进行检查分析；最后对 半径差不满足要求和轴线不重合的孔对进行标注。借助 CATIA 的 CAA 开发平台对相关算法进 行了系统设计，并验证方法的可行性。实例检查结果表明，该方法能够高效、准确的对钣金件 中匹配孔的半径差及轴线重合度自动检查。

Automatic Inspection of the Radius Difference and Axis Coincidence of Matching Holes in Sheet Metal Parts

Abstract: Aiming at the problems of low precision and easy omission of the matching hole’s radius difference and the axis coincidence ratio in the automobile sheet metal parts, the automatic inspection method of the radius difference and the axis coincidence degree of the matching holes in the sheet metal parts is proposed. Firstly, the obtained B-Rep three-dimensional model is topologically decomposed into the basic unit of the face by the method of the closing shell. Secondly, according to the characteristics of two semicircular arc lines and two straight lines on the cylindrical surface, the cylindrical surface is screened, and the circular holes and slots are extracted by using the cylindrical surface. Then the radius and axis of the circular hole and the slot are obtained respectively, and the point-to-point and point-to-line distance method is used to check and analyze the matching hole according to the hole matching principle. Finally, the hole pairs whose radius difference does not meet the requirements and the axes do not coincide is marked. The system design of related algorithms is carried out by using CAA development platform of CATIA, and the feasibility of the method was verified. The example inspection results show that the method can automatically and accurately check the radius difference and the axis coincidence ratio of the matching holes in the sheet metal parts.