基于点云数据的复杂型面数字化检测技术研究

Research on digital measurement technology based on point cloud data of complex surfaces

针对设计制造流程中复杂型面检测难的问题,建立了由数据获取、点云与计算机辅助设计模型匹配及偏差分析组成的数字化测量系统。采用格雷码加相移技术的三维非接触式光学测量技术,获取了待测零件的表面数据。为满足光学三角法要求,在测量机构中采用了定制光栅,提出了具有小扰动的改进最邻近点迭代算法进行点云与计算机辅助设计模型的准确匹配。在偏差分析中采用多分辨率层次分析法对测量点云与计算机辅助设计模型进行比较,为设计人员及时提供了精度分析数据,使设计制造检测成为一个反馈系统。以某型号轿车车灯配光镜为例,验证了该系统的可行性。

To deal with inspection difficulty in complex surfaces in product design and manufacture process, the digital measurement system consistied of data acquirement, Computer Aided Design(CAD) model and deviation analysis was proposed. It adopted gray code and phase shift technology to get point clouds of complex surfaces and used a custom-built grating to meet the demand of optical triangulation. Because point clouds and CAD model were in different coordinate system, the registration was needed. Improved Iterative Closet Point(ICP )method was proposed with translation matrix little variety to register the point cloud to CAD model. Owing to large point numbers of point clouds, it was not necessary to use all points for deviation analysis. A multi-resolution hierarchy analysis to deviation was presented. The result of deviation analysis could be referred by designers and was made as feedback to the system of design, manufacturing and measurement. The system was applied by a car lamp cover part. Application results suggested feasibility of the system.