Abstract: A coordinate control method was proposed for wheeled welding robot with rotational arc as sensor to track brokenline welding seam.Self-turning fuzzy controllerwas designed to complete coordinately controlling of cross-slider and wheels, and exactly welding seam tracking was realized by use of the controller.To make the robot's moving direction parallel to the welding seam direction, Sugerno fuzzy logic system was used as a filter to process the robot's orientation errors, which makes the robot move along when tracking lined section of welding seam and turn quickly when tracking covered section of welding seam.The experimental results show that the presented method is valid to track 60°broken-line welding seam and Z shape welding seam.