A stateful robotic weldment geometry measuring system

Nowadays, automated robot welding of components with low tolerances in series production is state-of-the-art. However, turning to small batch production particularly of parts with high tolerances, steel construction is just at the beginning of building economically efficient automated solutions. An analysis of small batch production revealed a fast detection of position and orientation of weldments as a key factor to a fully automated solution. While seam tracking for controlling the weld torch during the process is well established, geometry recognition of weldments is still to be solved satisfactorily. This article presents the development of a solution for state dependent error correction in geometry recognition for welding robots. Building on the basis of empirical studies on laser sensor behaviour, a robot controller add-on was programmed to be able to correct systematic errors occurring when using a sensor beyond current requirements of most vendors.