Linköping Electronic Conference Proceedings
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Modelica driven development of the thermal management control system for a zero emission yacht
Full text linkThis paper describes the use of a Modelica system model tosupport the development of a heat management control systemfor a fossil-free sailing yacht.Due to tight project timelines, the control system wasdeveloped and tested virtually, avoiding delays associatedwith waiting for the physical system to become available.The system model covers key functions such as heat recoveryand heat dumping, enabling automated testing of variousoperational scenarios.This approach not only accelerates development but alsoreveals early insights into interactions between thecontrol logic and system dynamics.The model is designed to be seamlessly replaced by the realsystem once it is built.Future comparisons between simulated and real-worldperformance will guide refinements to improve modelaccuracy and support model-based tuning of the controlsystem
A low complexity physics-based aging model for lithium ion cells with solid electrolyte interphase and lithium plating side-reactions
Full text linkIn this paper, we extend our previously presented lithiumion battery model to include electrochemical agingdynamics, considering both calendaric and cyclic agingbehavior. Accordingly, the Equivalent Hydraulic Model (EHM)is augmented with side reactions for Solid ElectrolyteInterphase (SEI) growth and lithium plating. The model isvalidated against experimental results, showing a level ofagreement that allows us to evaluate the effect of variouscharging and cooling strategies under real-world dutycycles. A case study concerning a battery electricpassenger vehicle that operates under changing seasonalconditions illustrates the advantages of using such amodel. Results show that the vehicle thermal management andthe recharge strategy play a critical role in ensuring along and safe operational life. In particular, and inagreement with the existing literature, more frequentcharges that maintain a lower average state of charge,together with a lithium plating conscious thermalmanagement, significantly extend battery lifetime
Identification and Elimination of Instabilities During Simulation of Highly Stiff Vehicle Electrical Power System Models
Full text linkIn vehicle electrical power system simulations, reliablemodels are required, especially for critical use cases suchas inrush currents, short circuits, and load dumpscenarios. These switching scenarios involve rapid changesin resistance and result in stiff models due to the fastdynamics. Instabilities are observed immediately afterswitching, highlighting significant numerical challenges.In this study, we investigate the origins of theseinaccuracies and propose robust solutions through improvedelectrical models and advanced numerical integrationtechniques with optimized error tolerance settings. Thesuggested decoupling approach employs physical and signalfiltering techniques to replace the variable resistor usedto simulate the fuse switching process. The nominal valuestrategy involves establishing an appropriate baselinevalue. The methods discussed yield stable and accuratesimulations when implemented with appropriately adaptedmodel-specific parameterizations
Interdisciplinary human-in-the-loop simulation framework for evaluation of actuation system concepts
Full text link This paper presents the initial work of an international collaboration with the aim of connecting distributed test rigs for evaluation of new flight control actuation system technologies. The involved partners are companies, universities, and institutions from Sweden and Brazil. Three test rigs with different capabilities and scopes are available through the partners involvement in the project, that includes an industrial robot-based flight simulator, a test rig for digital hydraulic actuators, and a full-scale Iron Bird for energy management and flight control actuation system testing. Connecting the test rigs facilitates a larger test scope and the evaluation of several technologies than using only one test rig. A model-based approach is adopted surrounding a virtual flight simulator used for model integration to allow testing both actuator performance and HMI aspects. The test case is a fictive fighter aircraft. The virtual flight simulator includes the aircraft behaviour, aerodynamics, propulsion, and flight control system. The virtual flight simulator is implemented in the physical one, and two flight missions are defined and flown by trained pilots. The generated data set is used by the actuator test rigs for performance evaluation. In the final part the actuator models are validated using the test data and integrated in the physical flight simulator for evaluating the impact of the actuator characteristics on aircraft performance and handling. The paper outlines the framework and method and illustrates the first part of the distributed testing by integrating pilot generated flight data for actuator performance evaluation and comparison
Development of Control Contraction Metric based methods on non-conventional aircraft configuration
Full text linkControl Contraction Metrics (CCMs) can be described as a non-linear control technique based indifferential dynamics on the framework of differential geometry. This work presents preliminaryresults on applying CCMs to the control of a Blended Wing Body (BWB) aircraft configuration,in particular, regarding flight conditions involving high angle of attack and medium Reynoldsnumber regimes. These preliminary results show that in absence of conventional stabilityequilibrium points, proper CCMs may allow effective control on aircraft dynamics given theadequate operational conditions. These conditions and configuration are expected to be presentin new concepts of Remotely Piloted Aircraft Systems (RPAS), extending their applicationsfrom planetary exploration to support the development of new transportation concepts incommercial airliners. Methods described, data, and results, are expected to be of applicationfor EXperimental Aircraft for European Leadership in Aviation (EXAELIA) project, a HorizonEurope international effort to de-risk and develop new concepts of passsenger aircraft to faceaerospace industry challenges by 2050.This work has been funded by the European Union under GA No. 101191922. Viewsand opinions expressed are however those of the author only and do not necessarily reflect thoseof the European Union or the European Climate, Infrastructure and Environment ExecutiveAgency. Neither the European Union nor the granting authority can be held responsible forthem
Improving Decision-Making of Civilian and Military Pilots Under Pressure: An Artificial Intelligence-Based Approach Using Prospect Theory
Full text linkThe expansion of Artificial Intelligence (AI), especially Large Language Models (LLMs), into safety-critical fields such as aviation raises fundamental questions about alignment with human expertise under risk. This study presents a controlled comparison of decision-making behaviour across professional pilots, lay participants and a LLM, each exposed to six hypothetical scenarios of Prospect Theory dilemmas and operational emergencies. A structured questionnaire measured risk preference, ethical reasoning, and context sensitivity; group differences were analysed using standard statistical methods. Results show that, in loss- and gain-framed dilemmas, both humans and the LLM display cognitive biases consistent with Prospect Theory. However, this mimicry fails to generalise: in operational risk scenarios, pilots consistently select the safest response, reflecting internalised safety culture and rapid pattern recognition. Lay participants show intermediate, more variable behaviour. By contrast, the LLM persistently selects risk-seeking, utilitarian strategies in operational domains, irrespective of prompt or training. The ethical dilemma scenario exposes further divergence: while nearly all humans act according to a deontological duty of care, prioritising those under their protection, the LLM favours maximising outcomes even when this increases risk for all. These findings show that current LLMs, despite surface-level alignment in abstract tasks, lack the tacit, context-dependent, and ethical knowledge needed for trustworthy deployment in safety-critical domains. Effective AI integration requires multi-layered alignment, expert feedback, explicit ethical constraints, and ongoing validation against expert practice. These results underscore the need for domain-specific alignment before adopting AI in aviation and related fields
Modelica Supported Automated Design
Full text linkWe propose a component-based, automated, bottom-up method to system design, using models expressed in the Modelica language. This bottom-up approach is based on a meta-topology that is iteratively refined via optimization. Each topology link is described by a universal component that is defined in terms of atomic components (e.g., resistors, capacitors for the electrical domain) or more complex canonical components with a well-defined function (e.g., operational amplifier-based inverters). The activation of such links is done via discrete switches. To address the combinatorial explosion in the resulting mixed-integer optimization problems, we convert the discrete switches into continuous switches that are physically realizable and formulate a parameter optimization problem that learns the component and switch parameters. We encourage topology sparsity through an L1 regularization term applied to the continuous switch parameters. We improve the time complexity of the optimization problem by reconstructing intermediate design models when components become redundant and by simplifying topologies through collapsing components and removing disconnected ones. To demonstrate the efficacy of our approach, we apply it to the design of various electrical circuits
Proposal for A Context-oriented Modelica Contributing to Variable Structure Systems
Full text linkContext-aware systems are widespread in our daily lives, but modeling languages that address the notion of context are rare. Variable structure systems (VSS) allow for structural and behavioral changes in physical models at runtime (while the simulation is running) based on different situations. It is desirable to explicitly describe under which contextual situation a specific variant of the simulation model should be used and how to implement the switching between these variants at runtime. In this case, contexts could be used to control the variability of context-aware systems. Equation-based modeling languages are suitable for modeling complex multi-domain, multi-physical systems, and among them, Modelica is the state-of-the-art. Unfortunately, the capabilities for VSS in Modelica are strongly limited. As a result, several frameworks have been proposed to address this problem by supporting different VSS types. However, it remains unclear which framework contributes to which VSS type. Furthermore, approaches have been developed to support VSS, but none can explicitly describe contexts and their transitions. In this work, we first introduce VSS and its different types. Then, we provide an overview of which framework targets which VSS type. Finally, we propose a new language extension based on Modelica, ContextModelica, that provides semantics for the direct context definition, enabling the use of context to control and manage variability
Advancements in Building-to-Grid Interactions: Thermo-Electric Coupling Models of Motor-Driven Devices
Full text linkBuilding-to-grid (B2G) integration transforms buildings into active components of the electricity grid, enhancing dynamic energy management and optimizing usage to reduce operational costs and carbon emissions. However, existing modeling tools for building and power systems often overlook or oversimplify the interactions between power system dynamics and building dynamics. This paper introduces Modelica-based thermo-electric coupling models for motor-driven devices in buildings, such as pumps and heat pumps. The developed models assess transient oscillations and negative active power in these devices within B2G systems. We compare the proposed models with a base model from the Modelica Building Library that uses a radiator and heat pump to maintain room temperature. The simulation results demonstrate that the motor-driven models effectively capture transient oscillations in current and power when the systems are activated and deactivated. Additionally, the occurrence of negative power when systems turn off is a critical factor in enhancing B2G system stability and energy efficiency. These findings underscore the model’s ability to improve grid support, advancing energy management practices in B2G applications
A comparative study of conventional lime kilns and plasma calcination: Techno-economic assessment and decarbonization potential
Full text linkLime production is essential in the chemical recovery cycle of chemical pulping mills, typically relying on fuel combustion and thus contributing to greenhouse gas emissions. While Nordic pulp mills mainly use carbon-neutral biofuels, future biomass scarcity underscores the need for sustainable biomass management and alternative lime calcination methods. Electrification presents a promising solution, as CO₂ emissions depend on the carbon intensity of the electricity grid, which increasingly relies on renewable sources. Electrified solutions offer chemical pulp mills the opportunity to function as biorefineries and potentially produce higher-value biofuels in a constrained market. Plasma calcination provides benefits over conventional lime kilns, such as faster reaction times, reduced reactor volume, and lower shell losses. This work develops mathematical models for conventional kilns and plasma calcination to evaluate their techno-economic feasibility and decarbonization potential. A sensitivity analysis identifies influential parameters, and energetic requirements for both technologies under different fuel scenarios are assessed along with CO₂ emissions and economic factors. Results indicate that while plasma calcination’s current decarbonization potential depends on the electricity grid’s carbon intensity, future projections show its competitiveness over conventional kilns, with significantly lower CO₂ emissions across regions. The economic viability of plasma calcination is further influenced by projected carbon prices and process parameters, which impact its specific electricity consumption