Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Inertial Measurement Unit based Human Action Recognition for Soft-Robotic Exoskeleton
    ( 2021)
    Kuschan, Jan
    ;
    Burgdorff, Moritz
    ;
    Filaretov, Hristo
    ;
    Krüger, Jörg
    Absence from work caused by overloading the musculoskeletal system lowers the life quality of the worker and gains unnecessary costs for both the employer and the health system. Exoskeletons can present a solution. Typically, such systems struggle with stiffness and discomfort and primarily a lack of battery lifetime. Soft-robotic exoskeletons offer a possibility to overcome these problems by increasing the system flexibility, not limiting the supported DoF and being actuator and joint together. Since soft-robotic exoskeletons can be designed only using power when supporting the wearer, it is possible to increase the battery lifetime by only acting on those actions for which the wearer needs support. Dealing with controls for soft-robotic exoskeleton one major difficulty is to find a compromise between saving energy and supporting the wearer. Having an action-depending control can reduce the supported actions to cover only relevant ones and increase the lifetime of the battery. The system conditions are to detect the user actions in real-time and distinguish between actions which require support and those which do not. We contribute an analysis and modification of human action recognition(HAR) benchmark algorithms from activities of the daily living, transferred them onto industrial use cases containing short and mid-term action and reduce the models to be compatible using embedded computers for real-time recognition on soft exoskeletons. We identified the most common challenges for inertial measurement units based HAR and compare the best-performing algorithms using a newly recorded data set overhead car assembly for industrial relevance. As a benchmark data set we focused on the "Opportunity" data set. By introducing orientation estimation, we were able to increase the F1 scores by up to 0.04. With an overall F1 score without a Null-class of up to 0.883, we were able to lay the foundation to use HAR for action dependent force support.
  • Publication
    Resilienz im strategischen Management produzierender Unternehmen. Konzeptpapier
    (Fraunhofer IPT, 2021)
    Schuh, Günther
    ;
    Patzwald, Marc
    ;
    Krebs, Leonie
    ;
    Dumitrescu, Roman
    ;
    Rasor, Rik
    ;
    Sihn, Wilfried
    ;
    Steinwender, Arko
    ;
    Sala, Alessandro
    ;
    Kohl, Holger
    ;
    Knothe, Thomas
    ;
    Singer, Katrin
    ;
    Hecklau, Fabian
    Während Resilienz in anderen Managementdisziplinen, wie etwa im Bereich der Lieferketten, bereits seit längerer Zeit Einzug gehalten hat, existieren für das strategische Management von produzierenden Unternehmen kaum systematische Untersuchungen zu dessen Integration. Im Rahmen des Konzeptpapiers werden dem Leser daher konzeptionelle Ansatzpunkte aufgezeigt, wie Resilienz als neue normative Zielgröße in exemplarischen Teilstrategien des Strategiesystems produzierender Unternehmen Berücksichtigung findet (bspw. der Unternehmens-, Technologie- und Innovations-, Engineering- sowie Produktionsstrategie).
  • Publication
    Modularized and Reconfigurable Machine Tool Frames based on Polyhedral Building Blocks
    (Fraunhofer Verlag, 2021)
    Peukert, Bernd Walter
    The versatility of modern manufacturing is ever-increasing. Reconfigurable manufacturing systems are one proposed solution to offer concurrent flexibility and productivity and enable manufacturing systems to adapt to rapidly changing requirements. However, modern machine tools do not fully comply with the requirements of the reconfigurability paradigm. One reason lies in the limited changeability of the machine tool frame itself, as machine tool frames are usually designed as platforms with a limited set of predefined configurations. This thesis presents a mechatronic building block system for the modularization of machine tool frames. The building block system consists of passive, smart, and active building blocks. Following a bottom-up approach, the research starts with the idea of tessellating the machine tool frame with a suitable polyhedral geometry. A novel methodology is used to grade several geometries and leads to the selection of the hexagonal prism as the basic building block geometry. The investigations proceed with the design and experimental investigation of the individual building blocks and concludes with the configuration and realization of a modular and reconfigurable three-axis milling machine tool.
  • Publication
    Validierung von Methoden zur Vermeidung von Liquid Metal Embrittlement an realitätsnahen Prinzipbauteilen (IGF 21483 BG / P 1488)
    ( 2021)
    Meyerdierks, Martin
    ;
    Schreiber, Vincent
    ;
    Böhne, Christoph
    ;
    Seitz, Georg
    ;
    Jüttner, Sven
    ;
    Meschut, Gerson
    ;
    Rethmeier, Michael
    Ziel des Forschungsprojekts ist es, eine Korrelation zwischen Gleeble-Heißzug-Prüfverfahren und Widerstandspunktschweiß-basierten Prüfverfahren herzustellen. Es soll die Effektivität von Methoden zu Vermeidung von Liquid Metal Embrittlement an realitätsnahen Prinzipbauteilen bewertet werden. Weiterhin soll Kenntnis über Auswirkungen von LME Rissen auf das Tragverhalten von realitätsnahen Prinzipbauteilen gewonnen werden.
  • Publication
    Requirements-driven Identification and Validation of Reusable System and Development Elements
    (Fraunhofer Verlag, 2021)
    Sünnetcioglu, Atakan
    The well-known benefits of reuse in product development are reduced necessary effort, shorter development cycles and increased product quality due to the more mature solutions that are integrated into new products. Although it sounds paradox, reusing existing solutions in new development projects is one of the possibilities to increase the innovation power of a company. By applying reuse in a systematic way where applicable, product development teams can create additional resources for more innovative aspects of new products. This book reveals a requirements-driven approach for the identification of reuse in development projects. In this approach, product developers compare requirements of ongoing and completed projects to identify related requirements, which are suitable for reuse since they can be fulfilled with same solutions. However, comparison of requirements specifications is an elaborate and time consuming task for product developers.
  • Publication
    Einsatzverhalten keramisch gebundener Gleitschleifkörper
    (Fraunhofer Verlag, 2021)
    Eulitz, Alexander
    Zu den kritischen Erfolgsfaktoren beim Gleitschleifen zählt insbesondere die Wahl eines geeigneten Schleifkörpers sowie passender Parameterwerte im Rahmen der Prozessauslegung. Obwohl die Anfänge der Gleitschleifbearbeitung vermutlich bis in das Altertum zurückreichen, basiert die Prozessauslegung nach wie vor vordergründig auf Erfahrungswissen der Anwender. Um eine wissensbasierte Prozessauslegung zu ermöglichen, werden in dieser Arbeit grundlegende Erkenntnisse zum Einsatzverhalten keramisch gebundener Gleitschleifkörper unterschiedlicher Form und Größe beschrieben. Weiterhin werden die Voraussetzungen für eine Übertragbarkeit auf industrielle Anwendungsfälle geschaffen.
  • Publication
    Selbstoptimierendes System zur aktiven Schwingungskompensation in Werkzeugmaschinen
    (Fraunhofer Verlag, 2021)
    Mewis, Jan
    Die Werkzeugmaschinenindustrie ist charakterisiert durch ständig steigende Anforderungen an Fertigungskosten und -qualität. Der dadurch zunehmenden Belastung der Werkzeugmaschinen muss durch geeignete Maßnahmen entgegengewirkt werden. Insbesondere das dynamische Verhalten hat einen hohen Anteil an der erreichbaren Produktivität und Fertigungsgenauigkeit. Die Hochgeschwindigkeitsbearbeitung erfordert eine Verringerung der Massen. Gleichzeitig ist jedoch auch eine Erhöhung der Dämpfung und der Steifigkeit gefordert. Im Rahmen dieser Arbeit wurde die Entwicklung eines aktiven, robusten, sowie sich selbst identifizierenden und optimierenden Systems zur Verbesserung des dynamischen Verhaltens von Werkzeugmaschinen durchgeführt und evaluiert. Die Modelle und Grundlagen hierfür sind systematisch erarbeitet, nachvollziehbar dargestellt und zielgerichtet miteinander verknüpft worden. Die Dämpfungswirkung konnte anhand eines aktiven Mehrgrößensystems mit signifikanten Interaktionen nachgewiesen werden, das seriell in den Kraftfluss eines Maschinengestells integriert wurde. Zusammen mit den entwickelten Methoden sind die Modelle auf beliebige linearisierbare aktive Mehrgrößensysteme anwendbar.
  • Publication
    Production environment of tomorrow (ProMo)
    ( 2021)
    Kuschan, Jan
    ;
    Müller, Vinzenz
    ;
    Monchinger, Stephan
    ;
    Heimann, Oliver
    ;
    Niebuhr, Carsten
    ;
    Kabha, Oday
    Small defects in the grain or major damage to a moulded part or tool can bring production to a standstill. SMEs in particular have neither the personnel nor the equipment to repair such damage on their own, so they send it to specialised contractors. The repair process is carried out manually, depending on the accuracy requirements, and is usually completed by a finishing process. This work requires qualified personnel and, at the same time, requires a lot of time in case of larger damages. In this paper we present a way to map the Maintenance, Repair and Operations (MRO) process chain in a partially automated manner. The symbiosis of individual technologies results in a significantly increased efficiency of the MRO process chain, which continues to focus on people and their process knowledge. While Directed Energy Deposition (DED) for the MRO of moulded parts is used widely, usually a high manual effort in measuring the component geometries and teaching of the machine tool paths is necessary. However, there are clear advantages compared to the manufacture of new parts or manual laser welding repair. At the same time, the resource and energy requirements can often be significantly reduced compared to new part production. ProMo focuses on automating the time-consuming machine programming by reducing the number of necessary work steps in CAD/CAM-based program creation. Based on a subsequent robot-guided scan, a digital actual 3D model is generated. Due to intelligent path planning algorithms, no manual programming of the robot is necessary and at the same time it is possible to detect components of different sizes, shapes and covers in this system with a minimum of effort. In addition, the operator passes on elementary information, such as the approach path of the milling head, to the subsequent processes by means of finger gestures and can thus significantly reduce tedious CAM programming steps. Now, the scanned component is transferred to a 3D-CAD model and a target/actual comparison is created for the damaged areas. Those are milled out in a defined manner and then restored using DED.