Analysis on an uncalibrated image-based visual servoing for 6 DOF industrial welding robots

It is of quite great significance to research on automatic operation for industrial welding robots. This paper presents an uncalibrated control scheme for guiding 6 DOF welding robot to track a target via image-based visual servoing. Recently this method has been a novel trend for automation application of the welding robot and raises great interests among researchers. This closed-loop control law is based on the feedback of visual features from eye-in-hand camera. It can be applied in controlling the industrial robot to track weld seam or to guide the robot somewhere without knowing correct robot kinematic model or camera calibration. In the paper, Lyapunov method is employed to analyze the necessary and sufficient conditions for asymptotic stability and robustness of this control scheme. This proposed scheme is verified to ensure the convergence of image-features to desired reference image. Finally the image-based visual servoing simulation for 6 DOF robot is presented, which testifies the steady-state tracking behaviour and good performance.