Automatic compensation of workpiece positioning tolerances for precise laser welding

Precise laser welding plays a fundamental role in the production of high-tech goods, particularly in precision engineering. In this working field, precise adjustment and compensation of positioning tolerances of the parts to be welded with respect to the laser beam is of paramount importance. This procedure mostly requires tedious and error-prone manual adjustment, which additionally results in a sharp increase in production costs. We therefore developed a system which automates and thus accelerates this procedure significantly. To this end, the welding machine is equipped with a camera to acquire high resolution images of the parts to be welded. In addition, a software framework is developed which enables precise automatic position detection of these parts and adjusts the position of the welding contour correspondingly. As a result, the machine is rapidly prepared for welding, and it is much more flexible in adapting to unknown parts.This paper describes the entire concept of extending a conventional welding machine with means for image acquisition and position estimation. In addition to this description, the algorithms, the results of an evaluation of position estimation, and a final welding result are presented.

Approaches for high-speed melt pool detection in laser welding applications

In this paper several approaches for the detection of the melt pool circle (i.e. its position and radius) in laser welding applications are described. Instead of indirectly examining the evolution of the melt pool via the radiation of plasma that is generated during the welding process, we use a direct view onto the melt pool that is possible in a narrow wavelength band with a coaxial aligned high speed CMOS imaging sensor. Since visual inspection is often a bottleneck in mass production, we focus on high speed approaches that enable real-time monitoring of the melt pool parameters

Sign Segmentation with Changepoint-Modulated Pseudo-Labelling

International audienceThe objective of this work is to find temporal boundaries between signs in continuous sign language. Motivated by the paucity of annotation available for this task, we propose a simple yet effective algorithm to improve segmentation performance on unlabelled signing footage from a domain of interest. We make the following contributions: (1) We motivate and introduce the task of source-free domain adaptation for sign language segmentation, in which labelled source data is available for an initial training phase, but is not available during adaptation. (2) We propose the Changepoint-Modulated Pseudo-Labelling (CMPL) algorithm to leverage cues from abrupt changes in motion-sensitive feature space to improve pseudo-labelling quality for adaptation. (3) We showcase the effectiveness of our approach for category-agnostic sign segmentation, transferring from the BSLCORPUS to the BSL-1K and RWTH-PHOENIX-Weather 2014 datasets, where we outperform the prior state of the art

Künstliche Intelligenz und Digitaler Zwilling in der Produktion – Forschung zu Leitanwendungen und dem Transfer in die Industrie

Der Einsatz von Methoden der künstlichen Intelligenz (KI) in der automatisierten Produktion ist aktuell noch immer sehr herausfordernd. Angepasste Lösungen der KI lassen sich zu wenig auf andere Anwendungsfälle übertragen, die Einrichtung und Bedienung der KI-Ansätze erfordert tiefes fachliches Knowhow und deren Ergebnisse sind durch Menschen oft schwer und nicht vollständig nachvollziehbar. Zudem liegen Datenschätze zum Teil in Unternehmen vor, es fehlt aber an Werkzeugen, diese auszuwerten. In einem von der Carl-Zeiss-Stiftung geförderten interdisziplinären Projekt wird diesen Problemstellungen forschungsmäßig begegnet und Lösungsmöglichkeiten anhand industrieller Leitanwendungen aufgezeigt. Neben den Leitanwendungen und der zugesagten industriellen Kooperation wird das „Center for industrial AI“ als dauerhafte Struktur an der Hochschule Heilbronn eingerichtet, um den Ergebnistransfer nachhaltig zu sichern