Universal arc welding robot teaching method regarding cylinder intersection welding seam

The invention relates to a universal arc welding robot teaching method regarding a cylinder intersection welding seam. The method is suitable for four kinds of cylinder intersection welding seams, namely central vertical crossing, central inclined crossing, eccentric vertical crossing and eccentric inclined crossing. The method is characterized in that a pose transformation matrix of a workpiece coordinate system relative to a robot-based coordinate system is established and calibration of a cylinder intersection welding seam workpiece coordinate system is realized by operating a robot to teach four characteristic points on a cylinder intersection welding seam workpiece on line; a cylinder intersection discrete point coordinate and a corresponding welding gun pose under the robot-based coordinate system are generated through the corresponding interpolation algorithm, so that generation of a cylinder intersection welding seam track and welding gun pose fitting are realized. The method has the following advantages: the arc welding robot only needs to teach four characteristic points in a cylinder intersection welding seam welding task; the teaching efficiency is high, the track interpolation accuracy is high and the adaptability is strong; and the working efficiency and the welding quality of the arc welding robot for welding the cylinder intersection can be greatly improved.