Dipl.-Phys.

König, Niels

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  • Publication
    A concept for a large-scale non-contact strain measurement system using nanostructures
    ( 2024-06-24)
    Ulm, Andreas
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    König, Niels orcid-logo
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    Schmitt, Robert
    The monitoring of mechanical strain is essential in developing new materials, designing mechanical components and structural health monitoring. In applications where contactless measurement is required, a novel method is needed to allow for absolute and long-term measurements. We discuss a measuring principle based on diffractive nanostructures featuring these advantages. For the measurement, periodic nanostructures are applied to a component, illuminated with a defined light source and the resulting color impression is monitored. The relationship between the stretched geometry of the nanostructure and diffraction spectra allows to quantify the component’s strain. We present a guide-line for the design of industrial applicable and sensitivity-optimized nanostructures and discuss the advantages in different application scenarios.
  • Publication
    Empirical study on 5G NR Adjacent Channel Coexistence
    ( 2023)
    Caro, Jordi Biosca
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    Ansari, Junaid
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    Sayyed, Ahmed Raza
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    Bruin, Peter de
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    Sachs, Joachim
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    König, Niels orcid-logo
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    Schmitt, Robert
    5G New Radio (NR) non-public network deployments for industrial and enterprise applications are becoming highly popular in locally licensed and/or operator spectrum. The interference from coexisting networks on adjacent channels (in same or adjacent spectrum bands) could potentially deteriorate the performance characteristics in certain deployment scenarios. Appropriate interference mitigation is thus required to achieve the desired performance levels. In this paper, we present our detailed empirical results on the performance impact of coexisting 5G NR networks operating on adjacent channels. Our experimental study conducted on an industrial shopfloor reports the impact on the downlink and uplink latency and throughput when using the same and different Time Division Duplexing patterns for coexisting networks. Our empirical evaluation includes realistic user equipment deployment locations and traffic load conditions. We also present our results on different mitigation techniques to counter the adjacent channel interference effects.
  • Publication
    Automated Manufacturing of Microtissue Based Osteochondral Implants: The »JOINTPROMISE« Platform
    ( 2022)
    Krieger, Judith
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    Nießing, Bastian
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    König, Niels orcid-logo
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    Luyten, Frank P.
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    Papantoniou, Ioannis
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    Schmitt, Robert H.
    Over 300 million cases of osteoarthritis were reported in 2017, stating one of the most prevalent chronic joint diseases worldwide characterized predominantly by long-term progressive cartilage and subchondral bone degeneration. Conventional therapy approaches utilize pharmacotherapy mostly for pain relief and at end stage disease treated by whole joint replacement surgery to retrieve some mobility and function. Novel Regenerative Medicine (RM) strategies employing Tissue Engineered implants could enable cure, more than care, of such life-constraining disabilities to meet the rising demand for medical interventions due to an ageing world population. Engineering joint tissue implants for the regeneration of the cartilage-bone unit of the joints remains a challenge due to the complex structural organization and functionality of native joint tissue. The use of microtissue/spheroid platforms has enabled differentiation and maturation of cartilage intermediates and gives hope for the engineering of efficient large-scale implants for osteochondral regeneration. However, there is still lack of enabling technologies for scaling of these approaches and robust manufacturing with end-to-end automation of such advanced therapeutic medicinal products (ATMPs). To allow sufficient scaling, overcome risks of contamination as well as inconsistent product quality in manual production procedures, the automated, GMP-compliant manufacturing platform »JointPromise« is developed. By establishing a robust, large-scale manufacturing process, a reliable microtissue-based product for the treatment of deep osteochondral defects can be generated with suitable productivity. The platform concept is based on the translation of Standard Operating Procedures (SOPs) for microtissue production, harvest and condensation into a sequence of automated process steps. Derived process design criteria and technical specifications result in device requirements for an automated production process. After initiating the conceptualizing stage of the platform design by creating a 2D layout according to the material flow of the translated SOPs, the final arrangement of devices was optimized in the overall 3D CAD model. The resulting production platform model combines all required devices for cell cultivation, microtissue harvest and ATMP production in an overall layout consisting of pipetting units, an incubator, centrifuge, bioprinter and housing for a defined hygienic environment. Following the SOPs, about 28,000 microtissue spheroids can be produced within 21 days of culture out of 1 mL cell suspension per tissue culture plate. To reach the required productivity of around 100 tissue culture plates per implant, the production platform will need to process around 70 L of liquids during seeding and harvest processes and 5 L per cell media change to produce around 2.8M microtissue spheroids in 21 days. The build-up of the »JointPromise« platform is followed by the implementation of the control software COPE (Control Operate Plan Execute, Fraunhofer IPT, Aachen, Germany) for process controlling and monitoring during cell seeding, cultivation and harvest.
  • Publication
    Meeting the requirements of industrial production with a versatile multi-sensor platform based on 5G communication
    ( 2020)
    Schmitt, Sarah S. orcid-logo
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    Mohanram, Praveen
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    Padovani, Roberto
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    König, Niels orcid-logo
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    Jung, Sven
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    Schmitt, Robert H.
    To face the requirements of current and future industry and to push the digitalization of factories, an international consortium in the project 5G-SMART develops a versatile multi-sensor platform communicating via 5G. To achieve an adaptable and flexible system, the embedded device is designed in a modular approach, consisting of a local processing core, integrable field sensors and a 5G modem. This paper covers the concept and design of the elaborated versatile multi-sensor platform and therewith presents a system that overcomes the limitations of current sensor systems and enables an interconnected real-time monitoring for production industry.
  • Publication
    Comparison of 5G enabled control loops for production
    ( 2020)
    Kehl, Pierre orcid-logo
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    Lange, Dirk D.
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    Konstantin Maurer, F.
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    Németh, Gábor
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    Overbeck, Daniel
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    Jung, Sven
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    König, Niels orcid-logo
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    Schmitt, Robert H.
    Concepts such as Industry 4.0 and Industrial Internet of Things aim for a digital transformation of manufacturing companies. One aspect that is to be transformed is the shop floor, where the interconnection of machines and sensor devices plays a major role. 5G positions itself to be a key technology to enable this transformation by providing reliable, low latency, and high bandwidth communication which is required by industrial use cases. However, so far it is still unclear which role 5G will play in industrial networks and how it can be integrated into existing factory ecosystems. Therefore, this paper presents three different data flow architectures that illustrate how 5G can be integrated into the production IT and how it can coexist with a factory cloud system. Furthermore, we describe a use case that reflects typical industrial communication requirements and will be used in the future to evaluate the different architectures. We conclude by presenting a validation p lan and an outlook on future work.
  • Publication
    OCT measurement of aspheric polymer lenses for adaptive assembly of micro optical imaging objectives
    ( 2020)
    Riediger, Max
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    Berger, Marvin
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    Hoeren, Maximilian
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    König, Niels orcid-logo
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    Zontar, Daniel
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    Brecher, Christian
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    Schmitt, R.
    Miniaturized optics are main components in many different areas ranging from smart devices over medical products to the area of automotive and mobility. Thus several million if not billions of small lenses are merged into objectives. The optical function of these objectives can only be guaranteed, if all optical surfaces not only meet the form tolerances of the optical design but also have the right position with respect to another. To ensure this, a measurement method has been developed, that is able to measure the surface form and the centration of both functional surfaces of single micro optical polymer lenses. The method bases on Optical Coherence Tomography (OCT) so that due to the tomographic measurement principle both functional surfaces can be captured in one measurement. Key challenge is the reconstruction of the geometric form of the functional surface facing away from the measurement head since it is distorted due to the refraction of light on the functional surface that faces towards the measurement head. The distortion needs to be corrected by means of backwards ray tracing. The OCT-based characterization of the single optical elements allows an adaptive assembly of micro optical imaging objectives by feeding back the individual shape of every single optical component to the assembly process. This information can be used for either selective assembly or the compensation of individual component tolerances by matching components whose form and centration errors cancel each other out in the overall system.
  • Publication
    Optical Coherence Tomography. Towards New Medical Applications
    ( 2018)
    König, Niels orcid-logo
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    Riediger, Max
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    Wilhelm, Dirk
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    Witte, Michael
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    Masamune, Ken
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    Schmitt, Robert
    The non-invasive imaging technology OCT (Optical Coherence Tomography) is based on low-coherence interferometry and can enable a three-dimensional representation of organic tissue with close to microscopy resolution. With penetration depths of several millimeters, resolutions of a few microns, real-time scanning rates, and miniaturization opportunities, imaging is a frequently sought-after clinical field. Clinical experts from various disciplines described concrete needs as part of the "Research Alliance OCT for Medicine" FOMed, which can be optimally addressed through the future use of OCT technology. Improved diagnoses, gentler therapies for the patient or the simultaneous acceleration of the surgical workflow are the expected benefits - the potential advantages and the applications in question show the great potential for using OCT in medicine.
  • Publication
    Design of a modular framework for the integration of machines and devices into service-oriented production networks
    ( 2017)
    Jung, Sven
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    Kulik, Michael
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    König, Niels orcid-logo
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    Schmitt, Robert
    In todays production systems flexibilisation and process data tracking becomes more and more important, in order to face the challenges coming with an individualised production and highly linked processes. The required digital interconnection of machines and systems is time-consuming and costly, due to the variety of different interfaces and protocols. Within this work, we present a framework for a flexible and less complex integration of machines and devices into production networks and systems. This helps to make existing machines Industry 4.0 ready and unify data interchange for more dynamic and linked production systems.
  • Publication
    Wissenschaft in der Produktionspraxis
    ( 2017)
    Schmitt, Robert
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    Brand, J.
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    König, Niels orcid-logo
    Die Produktionstechnik ist untrennbar mit der Wissenschaft gekoppelt. Denn einerseits werden die gewonnenen wissenschaftlichen Erkenntnisse in wirtschaftlich profitable Prozese und Produktionssysteme umgesetzt und andererseits profitiert die Wissenschaft von produktionstechnischen Ergebnissen als Ausgangsgrößen zur Erstellung von Erklärungsmodellen. Diese auf Reziprozität beruhende Beziehung wird vom Internet of Production befeuert und führt in letzter Konsequenz vom Experimentierfeld zur "World-as-Lab". Strukturelle Veränderungen und Auflösung der linearen Ursache-Wirkungsbeziehungen in einer zukünftig vernetzt organisierten Produktionsumgebung lassen eine paradigmatsiche Neuordnung erwarten. Diese erfordert über die Interdisziplinarität hinaus eine Erweiterung eines kausal-li nearen Optimierungsgedankens hin zur einer Entwicklung von multi-modalen Bewertungskriterien für pareto-optimale Lösungen unter produktionstechnischen Restriktionen. Offene Forschungsfragen liegen auf den Feldern der Erfassung, Strukturierung und Nutzung veredelter Daten, die Analyse vernetzer Systeme mit Parameteridentifikation, Black- and White-Box Modellierung und latenzarmer Simulation, die Auslegung komplexer Wertschöpfungsnetzwerke und die Beschreibung sozio-technischer Systeme mit menschlichen und technischen Akteuren und der automatisierten Unterstützung bei der Entscheidunsfindung.
  • Publication
    Monitoring of laser material processing using machine integrated low-coherence interferometry
    ( 2017)
    König, Niels orcid-logo
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    Kunze, Rouwen
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    Schmitt, Robert
    Laser material processing has become an indispensable tool in modern production. With the availability of high power pico- and femtosecond laser sources, laser material processing is advancing into applications, which demand for highest accuracies such as laser micro milling or laser drilling. In order to enable narrow tolerance windows, a closedloop monitoring of the geometrical properties of the processed work piece is essential for achieving a robust manufacturing process. Low coherence interferometry (LCI) is a high-precision measuring principle well-known from surface metrology. In recent years, we demonstrated successful integrations of LCI into several different laser material processing methods. Within this paper, we give an overview about the different machine integration strategies, that always aim at a complete and ideally telecentric integration of the measurement device into the existing beam path of the processing laser. Thus, highly accurate depth measurements within machine coordinates and a subsequent process control and quality assurance are possible. First products using this principle have already found its way to the market, which underlines the potential of this technology for the monitoring of laser material processing.