Abstract: Teaching and playback are usually used on welding robot to weld a part. To make sure the implementation of this mode, it is needed to locate the part using artificial sport welding in the front process, which could cause location error and make the actual track deviate from the teaching track. A welding track offline detection device using stripe type laser sensor was proposed for solving the problem. The laser sensor was mounted at the end of the robot. The robot moved along the weld trajectory before welding. The information of the weld track section was gotten and the feature points were extracted by the laser sensor. The weld trajectory was gained using NURBS curve fitting. Experimental results show that the algorithm is highly accurate and efficient, and can satisfy the requirement of robot's automatic searching track for real-time response.

Key words: non-uniform rational B-spline, curve filtering, curve fitting, laser detection sensor, weld seam measurement