基于点云的机器人激光焊接轨迹自动提取方法

Automatic Extraction Method of Welding Trajectory from Point Cloud for Robotic Laser Welding

为越过从点云到CAD模型的重构,实现自由摆放立板的自动焊接,提出一种基于测量点云的机器人激光焊接轨迹自动提取方法。利用均匀采样法对点云进行简化,利用统计滤波剔除点云测量背景噪声,并对点云进行整体倾斜校正;提出一种数据扫描策略以实现组合立板顶面与底面的快速分割;在Alpha Shape算法识别出的立板顶面边界点基础上,采用距离约束去改进RANSAC算法,快速拟合出组合立板顶面边界轮廓;通过对分段顶面边界的快速排序及拓扑关系的还原,获得组合立板的角点;在此基础上,完成机器人激光焊接轨迹的自动构造。实验结果表明:该方法无需重构点云的CAD模型就可直接从测量点云中提取焊接轨迹,从而有效保证自由摆放立板的自动焊接。

In order to avoid the complicated computer aided design(CAD)model construction from point cloud and realize the automatic welding of freely placed vertical plates,an automatic extraction method of welding trajectory from point cloud for robotic laser welding was proposed.The uniform sampling method was used to simplify the point cloud,the statistical filtering was applied to eliminate the measuring noise,and the overall tilt correction of the point cloud was performed at the same time.Then a data scanning strategy was established to realize the rapid segmentation of the top and bottom surfaces of the vertical plates.After that,based on the boundary points on the top surface identified by the Alpha Shape algorithm,distance constraints were used to improve the RANSAC algorithm to quickly fit the top boundary of the vertical plates.Subsequently,the key corners of combined vertical plates were identified through quick sorting and restoration of topological relationships of top boundary segments.On basis of these,the automatic extraction of welding trajectory for robotic laser welding was realized.The experimental results show that the proposed method can directly extract the welding trajectory from the point cloud without CAD model reconstruction,realizing automatic welding of freely placed vertical plates.