Linköping Electronic Conference Proceedings
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Diagnosing Newton’s Solver Convergence Failures in the Initialization of Modelica Models
Get PDFThe convergence failure of iterative Newton solvers duringthe initialization of Modelica models is a seriousshow-stopper, particularly for inexperienced users. Thispaper presents the implementation in the OpenModelica toolof methods presented by two of the authors in a previouspaper, to help diagnosing and resolving these convergencefailure by providing ranked lists of potentially criticalstart attributes that might need to be fixed in order tosuccessfully achieve convergence. The method also provideslibrary developers with useful information about criticalnonlinear equations, that could be replaced by equivalent,less nonlinear ones, or approximated by homotopy for morerobust initialization
Integration of Physical and AI Models Using Open and Interoperable Standards: A Model-Based Methodology for Autonomous Robot Development
Get PDFThe development of Cyber-Physical Systems, particularly inthe field of autonomous mobile robotics, often relies onproprietary environments, which limit flexibility andinteroperability. This paper proposes a modular andopen-source methodology that enables the modeling andsimulation of such systems using non-proprietary tools. Themethodology integrates Functional Mock-up Interfacestandard for model exchange, Open Neural Network Exchangestandard for Convolutional Neuronal Networks algorithmsintegration, ROS2 as robotic middleware, and Gazebo as thesimulation environment. To validate the approach, weapplied it in the development of a mobile robot thatnavigates autonomously by following traffic signals. Thisimplementation demonstrates that these open technologiescan be effectively combined, overcoming common integrationbarriers among proprietary tools. The proposed workflowprovides a practical alternative to proprietary solutionsand demonstrates the feasibility of integrating openstandards for the development of autonomous robotic systems
Modelica FMI based hybrid reinforcement learning enhanced trajectory planning for an ADR scenario for combined control of a satellite with a 7-axis robotic arm using Modelica/FMI
No full textThis work describes a novel hybrid reinforcement learningenhanced trajectory planning algorithm for an active debrisremoval scenario for combined control of a satellite with a7-axis robotic arm. A reinforcement learning algorithm iscombined with a correction algorithm and classicaltrajectory planning to handle the collision free approachof a chaser satellite to a target, and placing the gripperat the robots near the grasping point for use with acombined controller, which commands the satellite and itsrobotic arm simultaneously.The algorithm is verified using a complex simulationscenario study implemented in Modelica/FMI
Br(e)aking the Boundaries of Physical Simulation Models: Neural Functional Mock-up Units for Modeling the Automotive Braking System
Get PDFTesting real hardware and simulation models in combinationin a software- or hardware-in-the-loop set-up ischallenging. One of the key factors is the high demand foraccuracy in the simulation model. If classical modelingbased on physical principles is not sufficient to reach thedesired level of accuracy, hybrid modeling, the combinationof physical simulation models and machine learning can beapplied. In this publication, we train a hybrid model for acontrolled electric motor within the electro-hydraulicbraking system of a car under the conditions andrestrictions of a real engineering application in thefield. We apply state-of-the-art modeling patterns forthis, and further extend them with application specificmethodological optimizations. Finally, we investigate andshow the quantitative and qualitative advantages of theproposed approach for this specific application, resultingin a gain in accuracy by multiple factors
Automation Nation: Taming Complex V&V Workflows
Get PDFIn the realm of model verification, ensuringtraceability and repeatability is paramount forachieving Modeling & Simulation (M&S) credibilityand development efficiently. This paperexplores challenges and solutions for expressingcomplex model Verification & Validation (V&V)workflows that ensures readability while stillenables automation, parallelization and advancedcustomization of verification activities. This papercontributes a practical solution that is evaluatedthrough a detailed implementation within an in-house developed multi-purpose automation andVerification & Validation (V&V) framework
Development of a Multi-Physical Simulation Platform for Durability Prediction for Hyundai & Kia Electric Vehicles
Get PDFOne of the most popular ways of measuring signals for various components in vehicle on durability tracks will be Road Load Data Acquisition (RLDA) which gains load data through accelerated customer usages tests on either proving ground or field, using an instrumented vehicle. However, under the current circumstances, not only does a vehicle development cycle get shorter but also new mobility concepts keep being developed, a methodology is needed to cope with overall durability assessment in advance of a physical prototype being made for testing. In this study, this virtual testing methodology will be called Virtual RLDA. n this study, one of the most well-known electric vehicles in market is from Hyundai, with 2 in-wheel motors in rear which was chosen as the target vehicle. First, 6 major sub-systems such as vehicle controller, suspension, hydraulic brake, motor, battery and thermal management are modelled and validated separately, then they are integrated into one large vehicle model as a part of establishing the Virtual RLDA Platform which will be used for overall vehicle level durability development in early stage in Hyundai Kia Motor Company (HKMC)
Testing Large Scale System Simulation using Linear Implicit Equilibrium Dynamics
Get PDFThe concept of flattening where all model equations are collected in a single set is deeply hardwired into the Modelica language. While flattening enables effective symbolic manipulation such as the reduction of systems with a higher-index, it also imposes limitations. Two of these limitations are that the code generation for very large systems may not scale very well and that a statement on the regularity of the system often cannot be made before the flattening took place. Whereas it is difficult to overcome these limits in the general case, there is a subclass within Modelica models that is comparatively easy to precompile while still enabling the modeling of complex systems. This paper explores this path and presents first experiments on the scalability for larger systems
Enabling the Decarbonization of Regional Air Transport with Series Hybrid Electric Propulsion
Get PDFThe aviation industry faces significant environmental challenges, prompting the implementation of regulations to mitigate the adverse effect of carbon-based energy and associated emissions. While electrified flight is a promising pathway, limitations in specific energy density of batteries narrow down the application space to commuter and regional classes. Towards that direction, this work investigates the design and operation of a series hybrid electric 30-passenger regional aircraft. A multi-disciplinary framework is utilized, comprising modelling approaches for multi-point thermal engine design, physics-based electrical component sizing and performance, aircraft sizing, mission design, and environmental assessment. Distributed propulsion with up to three propellers per wing is evaluated for aerodynamic benefits. With optimal wing redesign, drag reduction benefits only reach 1\% for the selected aircraft class and flight velocities. Variable free power turbine speed operation is promising in reducing engine mass and improving performance of both thermal and electrical power systems. A combination of hybridization during take-off, climb and cruise defines the optimal design and operation guidelines for the hybrid concept. However, due to the increased mass of the battery and electrical power system, block fuel benefits only in the order of 5\% are reported, compared to a turboelectric aircraft. When compared with a conventional configuration of same entry-into-service year, the series concept is outperformed in the examined range of battery assumed technologies
Robust Priority Assignment applied to AFDX networks
No full textThe priority assignment of flows on an AFDX network impacts directly the end-to-end delay of all messages. This paper proposes the use of Robust Priority Assignment (RPA) in order to increase the additional interference that the most vulnerable virtual links of a AFDX network can support by decreasing their worst-case end-to-end delays through a better priority assignment. A comparison is performed with other stateof-the-art techniques used to assign priorities. The results shows that the use of RPA increases the network robustness in 307 in a sample configuration
A Review of Aircraft On-Board Systems: in the Context of Energy and Power Management
Get PDFOn-board systems in fighter aircraft are expected to deliver high performance under extreme and hostile operational conditions. As technology advances, system architectures are shifting from traditional federated configurations toward integrated and electrified designs characteristic of more electric aircraft. A range of architectural configurations, combining different powersources and consumers, can each fulfil the required system functionalities, offering distinct advantages and drawbacks. To tackle this problem, energy and power management offers a solution-independent, agnostic framework for assessing on-board system architectural decisions with respect to their impact on top-level aircraft requirements. Nonetheless, a clear understandingof the state-of-the-art and design sensitivities of these systems are needed in early stages of design. This study describes on-board system architectures and their associated trade-offs to quantify and compare architectural options available to system designers. It reviews on-board systems from both federated and more electric aircraft architectures, linking them to the aircraftlevel functions they fulfil and outlining key design trade-offs. The systems reviewed include flight control systems, hydraulic systems, fuel systems, electrical systems, pneumatic systems, environmental control systems, auxiliary power systems, emergency power systems, and landing gear systems. The review highlights that the interdependence and diversity of options of onboardsystems require robust integration frameworks that assess them collectively, rather than in isolation, to achieve a balanced architecture at the aircraft level.