Abstract: Teaching the orientations of a welding torch tends to occupy a great deal of time when arc welding robot welds spatial welding seam with lap joint. Therefore, a simple and convenient method of teaching is proposed. To teach the orientations of welding torch, the idea that the geometric constraints of the torch are used to automatically calculate the orientations of a torch is adopted. The position teaching is performed with arbitrary welding torch orientations. The torch orientations during welding are calculated according to the tangential vector of seam and the angles of torch required by welding process. For 3D curve seam, the simple teaching of torch orientations is needed only at the time when the local welding plane is not perpendicular to the Oyz plane of the robot base frame. And this kind of teaching can just be done by adjusting the robot’s angle of rotation around one axis. This method can dramatically cut down the time and the difficulty of teaching, and enhance the accuracy of the orientation teaching. The key techniques, such as the description of the orientations of a welding torch, the calculation of the welding orientation angles and the adjustmemt of the orientations of a welding torch, are presented. The test results on a curve seam with lap joint show the feasibility of this method.

Key words: Arc welding robot, Orientations of welding torch, Simple and convenient method of teaching, Welding orientation angle