Improving coaxial measurements in laser welding by correcting distortions of a laser focus lens with a wide field of view

Abstract

A compact, lightweight, and multifunctional head for robotic laser welding applications has been equipped with a camera to provide a real time image stream of the work piece for seam teaching, tracking, and inspection purposes [D. Iakovou, R. G. K. M. Aarts, and J. Meijer, “Integrated sensors for robotic laser welding,” in Proceedings of the Third International WLT Conference on Lasers in Manufacturing, Munich, Germany (AT-Fachverlag GmBH, Stuttgart, 2005), pp. 121–126; D. Iakovou, R. G. K. M. Aarts, and J. Meijer “Sensor integration for robotic laser welding processes,” (paper No. 2301), in Proceedings of the International Congress on Applications of Lasers and Electro-Optics (ICALEO), Miami, 2005 (unpublished)]. The camera uses part of the laser focusing optics. Research has been done to identify and correct for positioning errors introduced by the optical system. A robust camera and lens calibration method has been developed. Calibration and seam detection experiments have been performed and the results were used for seam tracking.

Sensor development and integration for robotized laser welding

“…A description of the camera and lens calibration procedure is presented in the following paragraphs. Parts of the optical calibration section have been published in the Journal of Laser Applications (Entzinger et al (2007)). …”