An Initial Point Alignment and Seam-Tracking System for Narrow Weld

Recently, laser vision sensors are widely applied in initial point alignment and seam tracking to improve the level of intelligent welding because of good characteristics. However, since the deformation of laser stripe is unobvious at the narrow weld with 0.2 mm width, these methods are not applicable for the narrow weld. Moreover, there are rare researches that could achieve initial point alignment and seam tracking of narrow weld simultaneously. Therefore, an initial point alignment and seam tracking system for narrow weld is proposed in this paper. At first, a laser vision sensor with extra light emitting diode light is used to obtain laser and weld seam image. Besides, the seam feature point is extracted and three-dimensional coordinates can be obtained with vision model. In addition, three controllers including decision controller, initial point alignment controller, and seam-tracking controller are proposed to achieve initial point alignment and seam tracking control in X- and Z-axis directions. Moreover, feature verification, Kalman filter, and output pulse verification are designed to improve the accuracy and stability of this system. Finally, many initial point alignment and seam-tracking experiments of narrow weld are conducted. Experimental results demonstrate that proposed system can well achieve initial point alignment and seam tracking of planar and curved surface narrow weld.