A Precise Initial Weld Point Guiding Method of Micro-Gap Weld Based on Structured Light Vision Sensor

Initial weld point guiding is the premise of intelligentized welding process. At present, many initial weld point guiding methods based on structured light vision sensors and passive vision sensors have been presented. However, the methods based on structured light vision sensors are not suitable for micro-gap weld and the methods based on passive vision sensors have large guiding errors, which limits their application for micro-gap weld. Therefore, a precise initial weld point guiding method of micro-gap weld is proposed in this paper. This initial weld point guiding method consists of two parts. In the vision sensing part, a structured light vision sensor with a narrow-band optical filter and a LED light is designed to acquire clear image, including laser stripe and micro-gap weld seam. Then, the image processing method is designed to detect feature point and the 3-D coordinates of the feature point can be obtained based on an established vision model. In the control part, combining the 3-D coordinates of the feature point with the initial weld point guiding model, the 3-D coordinates of initial weld point can be determined. Then, the initial weld point guiding controller is adopted to make welding torch align with the initial weld point. Finally, many initial weld point guiding experiments are carried out. Experimental results show that the proposed method can achieve the initial weld point guiding of planar and curved surface micro-gap weld accurately, and the guiding accuracy is improved compared with previous methods, which can be applied in welding production.