Numerical solution of the inverse kinematics and trajectory planning for an all-position welding robot

Abstract

Versatile welding robots designed for the field welding of box-type steel structures have the problems of low DOF (degree of freedom) and DOF coupling. A numerical solution method was developed for the inverse kinematics of the robot based on the layouts of actual welding processes to solve difficulties encountered in analytic methods. The numerical solution leads to a trajectory planning method based on the recursive algorithm to adjust the position and posture of the welding torch to realize smooth adjustments and transitions of the welding torch during welding of the right-angle turning point of the box-type steel structures. This approach provides trajectory planning for the all-position welding of box-type steel in an automatic algorithm that is applicable to different sizes of box-type steel structures. 摘要 针对所设计的新型箱型钢结构现场全位置焊接机器人存在欠自由度和自由度耦合等问题, 导出了一种基于实际焊接工艺需求的机器人逆运动学数值解法, 解决了采用传统解析法求解机器人逆运动学问题时存在的困难。在数值解的基础上, 进一步提出了一种基于递推算法的机器人运动轨迹规划和焊枪空间位姿调整方法, 实现了机器人在焊接箱型钢结构直角转角过程中的焊枪空间位姿的平滑过渡和调整。该方法不仅实现了箱型钢全位置焊接的轨迹规划功能, 有利于计算机自动求解, 而且可有效适应不同型号尺寸的箱型钢结构。