基于形态学细化法的弯管中线提取及研磨位姿计算研究

Research on extraction of bend pipe midline and calculation of grinding pose based on morphological refinement method

针对弯管内表面磁粒研磨工艺中手动采点产生的随机误差大、研磨间隙无法保证以及位姿不准确等问题,文中利用图像处理方法设计并实现了弯管中线的快速获取及坐标转换,从而完成研磨装置运动位姿计算。首先,对弯管磁粒研磨基本原理进行了分析,根据研磨过程中单颗磨粒受力状态得出弯管研磨过程中的基本工艺要求;其次,利用工业相机获取弯管图像,通过形态学细化及m邻接点分支去除方法得到弯管的轮廓中线;最后将中线像素点转换到工件坐标系下并进行函数化,结合弯管磁粒研磨工艺计算出研磨位姿,通过机械手离线编程软件对研磨位姿进行运动检查。利用形态学细化法对其结果进行m邻接点分支去除,可以较好地得到光滑的单像素弯管廓形中线;弯管中线的函数化有利于研磨位姿计算,可提高研磨过程的一致性和可控性。

In view of the large random error,unguaranteed grinding gap and inaccurate pose caused by manual point picking in the process of magnetic particle grinding of the inner surface of the bend pipe,the rapid acquisition of the bend pipe midline and the coordinate transformation are designed and realized by the image processing method,so as to complete the motion pose calculation of the grinding device.The basic principle of magnetic particle grinding is analyzed.The basic technological requirements of the bend pipe grinding process are obtained according to the strained state of a single abrasive particle in the grinding process.The bend pipe image is obtained by an industrial camera.The midline of the bend contour is obtained by morphological refinement and m⁃adjacency branch removal.The midline pixel points are converted to the workpiece coordinate system and functionalized,and then the grinding pose is calculated in combination with the magnetic particle grinding technology.The off⁃line programming software of manipulator is used to check the grinding position and pose.The morphological refinement method is used to remove the branches of m⁃adjacency points from the results,and the smooth midline of single pixel bend pipe profile can be obtained.The functionalization of the midline of the bend pipe is beneficial to the calculation of grinding pose,which can improve the consistency and controllability of grinding process.