Simultaneous calibration of a stereo vision system and a welding robot : an automated approach

For a vision guided industrial robot to be used in a production environment effectively and efficiently, it is important that such a system can be quickly and accurately calibrated. The work presented in this paper aims to develop a new method for calibrating a vision guided arc welding robot. This is achieved through automated calibration of the cameras and the optimised simultaneous calibration of a robot arm and robot mounted stereo vision system. The developed method can be implemented in practice and with minimum human intervention. The automatic calibration algorithm not only allows for a faster initial calibration, but also reduces the machine down-time for any subsequent calibrations after an accidental collision or if the camera fixture is relocated. Experimental results show that the proposed method can achieve the required accuracy for robotic arc welding applications.