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Item type:Publication, Access status: without files , Early model-based functional integration testing for aircraft systems architectures demonstrated on a hydrogen-powered propulsion unit(2025-10-25); ; ; ; Developing complex, hydrogen-powered aircraft and their on-board systems is challenging due to a vast design space, limited knowledge, and high uncertainties. Hence, the risk of undetected errors introduced during conceptual design increases. To address this, a method for early model-based functional integration testing as an integrated part of systems architecting is proposed. It includes simulation-based testing of functional behavior under nominal and off-nominal conditions based on executable architecture models, enabling the discovery of design errors and the down-selection of large design spaces. The method is demonstrated on a fuel cell-powered propulsion unit of a novel hydrogen-powered concept aircraft, showing its value for complex, novel systems in off-design conditions.Publicationtype: Conference Paper82 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Conceptual Design of IMA Platforms with Distributed A653-P4 Computing Modules for Next-Generation AircraftThe desire to further extend system functions on Integrated Modular Avionics (IMA) platforms necessitates advances in terms of module and network technology. The introduction of distributed computing concepts, such as passively cooled ARINC 653 Part 4 modules, is intended to enable fast local control loops for safety-critical systems on IMA, for which a central computing platform with an ARINC 664 backbone network would not meet timing requirements. Moreover, by mapping low-computing software applications close to their corresponding peripherals, a reduction of network load can be achieved. However, challenges persist during the conceptual design phase of IMA platforms, as peripheral localization and installation constraints induced by the aircraft geometry are difficult to consider due to high uncertainties. An approach that leverages parametric architecture design pattern within a model-based conceptual design framework is proposed. A use case study was conducted to identify conceptual variants of both state-of-the-Art Distributed IMA and next-generation architectures that feature distributed computing for a Virtual Research Aircraft (ViRAC). The study demonstrated that a fully model-based, formalised approach that integrates different disciplinary tools during early design iterations can lead to a reasonable platform draft in fewer design iterations.Publicationtype: Conference Paper61 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Evaluation metrics for systems architecting demonstrated on cooling system of hydrogen-powered concept aircraft(American Institute of Aeronautics and Astronautics (AIAA), 2024-01); ; ; Climate change presents a global challenge, with aviation significantly contributing to greenhouse gas emissions. To reduce the environmental impact of aviation, novel aircraft concepts incorporating renewable energy sources, such as green hydrogen, are being explored during the aircraft conceptual design phase. Low temperature proton exchange membrane fuel cells are currently being investigated as one possible technology for supplying power to the aircraft power train and on-board systems. However, the design of a cooling system for these fuel cells is challenging due to the small available temperature difference between fuel cell operation and ambient temperatures in hot day on-ground scenarios. Therefore, the development of novel cooling system architecture concepts is necessary. For this design problem, many conceivable architecture variants need to be investigated, resulting in a complex and large design space during systems architecting. To assist the engineer during systems architecting and to reduce the design space to promising architecture variants, the Systems Architecting Assistant (SArA) methodology is used. In this work, SArA is extended by a method for evaluating architecture performance based on the metrics complexity and risk, including a knowledge-based and a model-based approach. This helps engineers quantitatively compare system architecture alternatives, thereby simplifying the down-selection process. The developed metrics are applied to eight different cooling system architecture variants of a hydrogen-powered concept aircraft, enabling a rapid and partially automated approach for architecture evaluation. While the use of a combined knowledge-based and model-based approach proved beneficial, it became apparent that complexity and risk as high-level metrics provide limited insights and value in the decision-making process. To enhance the value of the evaluation method and to gain a deeper understanding of the architectures, a comprehensive investigation of the selected technologies becomes imperative.Publicationtype: Conference Paper44 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Seamless transitions from logical to physical avionics architecture models for preliminary aircraft system designThe transition of federated aviation electronics (avionics) systems to Integrated Modular Avionics (IMA) concepts leads to a higher integration of functions, which reduces the amount of equipment and therefore system mass. However, these benefits are accompanied by a strong increase in system complexity and more interdependencies. Moreover, further digitalization and automation of aircraft functions lead to a higher impact of avionics in terms of equipment number and energy consumption. One challenge arises from the fact that the IMA platform design starts in parallel to the design of other aircraft on-board systems, for which the platform shall provide resources like computing power. This leads to a high uncertainty during early design phases on the one hand and to a complex design process including many data and tool interfaces on the other hand. In order to meet these challenges, seamless model-based design approaches are being broadly investigated. For this purpose, standardized and automated interfaces between different design steps, tools, and stakeholders are needed. In this work, a formalized avionics architecture design process is proposed to support a seamless model-based tool chain from systems architecting to detailed system design. Methods to handle uncertainties, to provide standardized model interfaces, and to automate transitions between model abstraction levels are included. Overall, this reduces manual effort and the introduction of errors that would lead to high costs during system implementation.Publicationtype: Conference Presentation101 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Model-based framework for data and knowledge-driven systems architecting demonstrated on a hydrogen-powered concept aircraftAircraft development is a protracted process over many years. Novel concept aircraft with new energy sources and disruptive systems technologies are investigated during the aircraft conceptual design phase with the goal to achieve sustainable aviation. Current development cycles need to be accelerated to reduce time to market and development costs of novel aircraft, while still handling complexity and uncertainty of systems technologies. Therefore, a holistic framework for knowledge-based systems architecting using a model-based systems engineering approach is presented. This framework has the purpose to conserve and provide knowledge, i.e., information, data, and experiences about existing systems architectures, to the engineer. The developed framework consists of a database concept, a method for model-based systems architecting, and an interface to the overall systems design software tool GeneSys. Based on evaluating different modeling languages and tools, MathWorks System Composer is selected as most suitable tool for knowledge-based systems architecting. The developed framework is then demonstrated by conserving and reusing formalized knowledge for the design of a novel hydrogen-powered concept aircraft. On-board systems architecture models are saved in a database and automatically recreated reducing development time. The complete graphical representation could not yet be stored in a formalized manner partly reducing the advantage of a clear representation of model-based systems architecting. However, this did not reduce automatic recreation and evaluation capabilities.Publicationtype: Conference Presentation42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Systems architecting assistant (SArA) : enabling a seamless process chain from requirements to overall systems designThe path towards climate neutral aviation necessitates the development of novel aircraft concepts with disruptive technological solutions on board. The integration of such innovative technology concepts, such as hydrogen-based propulsion, has major effects on the aircraft's overall systems architecture. These integration-related effects are investigated in the scope of technology concept studies for which suitable systems architecture variants need to be created and evaluated beforehand. The knowledge-based systems architecting methodology~\textit{SArA} is proposed to ensure a seamless process chain during aircraft conceptual design starting with the definition of top-level aircraft requirements and ending with the execution of technology concept studies on overall systems design level. Different approaches for analyzing a given design problem within~\textit{SArA} are discussed: a top-level requirements-based approach, a system-level-based approach considering the individual systems, and a complementary functions-based approach. Moreover, an exploration of the architectural design space is integrated, and architecture variants are created and evaluated by employing a knowledge-based approach.~\textit{SArA} is then applied by exploring the design space of the electric power supply system for a hydrogen-powered concept aircraft, considering four different architecture variants. To this end, central and distributed layouts as well as different voltage specifications are discussed. The four architectures variants are evaluated based on criteria like complexity and risk.Publicationtype: Conference Paper134 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A Model-Based Approach for Early and Continuous Validation of Avionics Platforms up to Virtual Products and Hybrid Platforms(2022-09); ; The trend of today's aviation shows a steadily increasing complexity of avionics systems and related functions. Emerging technologies, such as multi-core avionics, mixed-criticality systems on shared resources, and the adoption of artificial intelligence (AI) in the field of avionics, will accelerate this growth by introducing additional synergies and new constraints. However, this trend makes the complex and non-automated development process of avionics platforms more time-consuming and error-prone. To keep the increasing complexity within reasonable limits and to avoid major design iterations, new methods are needed to continuously validate the design and implementation choices. In this paper, we present a model-based concept for early and continuous validation of avionics platforms under development through all their phases - design, implementation, testing and ultimately, integration.Publicationtype: Conference Paper64 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Rover orientation estimation using sun sensors for lunar and planetary exploration(2018-10); ; ; For space exploration rovers, knowing the exact local orientation is difficult due to the absence of Global Position System. From the global information (landing site) and the rovers images, the operator can make a rough estimation of its current position. Although this approach requires an active operator at all times, it is a very simple way of obtaining a position estimation. While the rover is in motion, wheel slippage is considered as it can be a source of heading error and diverge away from the intended motion plan. This problem is approached by tuning the wheel rotation speed based on the slip condition from terrestrial testing by mimicking the target environment. This method would be sufficient if the rover is landing at a pre-explored region such as the Apollo mission site. However, the above practice does not work when the rover travels to a previously unexplored area, or the condition of the explored lunar surface has changed over time. This results with the pre-tuned parameters will not be optimal for those cases. Therefore, we need a robust system that can track the rover's absolute orientation regardless of terrain conditions. In this paper, we will present an approach using commercial off-the-shelf photodiodes as sun sensors. Arrays of diodes are added onto the rover; each installed on a different surface to measure all necessary directions. The calibration process is initially performed in a controlled environment with a single artificial sunlight emitter to measure the sensor's functionality. The test results are then compared with the outdoor condition to measure errors such as environmental noise from surface albedo. As a final validation process, a field test is conducted to show the rovers local orientation based on the sun heading. The rover's yaw estimation is during the turn maneuver operations, and the deviation is compared to the angle derived from the ground truth.Publicationtype: Conference Paper71