Recognition of Weld Line and Automatic Weld Line Tracking by Welding Robot with Visual and Arc Voltage Sensing System

In automatic welding of thin steel plates, it is difficult to detect weld line by visual sensor, because the weld line is finer and the surface tends to reflect images of arcs and surrounding apparatus. Moreover, it is important to keep the optimum arc length in welding of thin plates. Therefore, a basic welding arc robot system with a visual sensor and an arc voltage sensor controlled by personal computers was constructed, and effects of lighting methods on detection of the weld line and the effectiveness of these control systems were experimentally investigated. As the result, it was made clear that reflection lighting method is more useful than the other conventional lighting methods for the recognition of the weld line and control systems constructed are effective for automatic welding of thin steel plates.