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METHODS FOR AUTOMATING MODEL VALIDATION: STEADY-STATE IDENTIFICATION APPLIED ON GRIPEN FIGHTER ENVIRONMENTAL CONTROL SYSTEM MEASUREMENTS
Saab Aeronautics, Linköping, Sweden.ORCID iD: 0000-0002-5773-3518
Saab Aeronautics, Linköping, Sweden.ORCID iD: 0000-0002-3120-1361
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.ORCID iD: 0000-0002-2315-0680
2016 (English)In: Proceedings of the 30th congress of the International Council  of the Aeronautical Sciences, International Council of the Aeronautical Sciences , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Model Validation and Verification (V&V) has historically often been considered a final step in the model development process. However, to justify model-based design decisions throughout the entire system development process, a methodology for continuous model V&V is essential. That is, model V&V activities should be fast and easy to reiterate as new information becomes available. Using a high fidelity simulation model of the Environmental Control System (ECS) in the Saab Gripen fighter aircraft as a guiding example, this paper further extends to an existing semiautomatic framework for model steady-state validation developed during ECS model validation efforts. Generic methods for identification of steady-state operation are a prerequisite for steady-state validation of industry grade physics based models against insitu measurements. Four different established methods for steady-state identification are investigated and compared: steady-state conditions on the standard deviation estimated from in-situ measurements, conditions on the variation coefficient, t-test on the slope of a simple regression line, and comparison of differently estimated variances. The methods’ applicability, on ECS measurements in particular, is evaluated utilizing steady-state identification needs defined during Gripen ECS model validation activities.

Model Validation and Verification (V&V) has historically often been considered a final step in the model development process. However, to justify model-based design decisions throughout the entire system development process, a methodology for continuous model V&V is essential. That is, model V&V activities should be fast and easy to reiterate as new information becomes available.

Using a high fidelity simulation model of the Environmental Control System (ECS) in the Saab Gripen fighter aircraft as a guiding example, this paper further extends to an existing semi-automatic framework for model steady-state validation developed during ECS model validation efforts. Generic methods for identification of steady-state operation are a prerequisite for steady-state validation of industry grade physics based models against in-situ measurements. Four different established methods for steady-state identification are investigated and compared: steady-state conditions on the standard deviation estimated from in-situ measurements, conditions on the variation coefficient, t-test on the slope of a simple regression line, and comparison of differently estimated variances. The methods’ applicability, on ECS measurements in particular, is evaluated utilizing steady-state identification needs defined during Gripen ECS model validation activities.

Place, publisher, year, edition, pages
International Council of the Aeronautical Sciences , 2016.
Keywords [en]
Gripen, Steady-state identification, Automating model validation, Historical data validation
National Category
Aerospace Engineering
Identifiers
URN: urn:nbn:se:liu:diva-142397Scopus ID: 2-s2.0-85013638563ISBN: 978-3-932182-85-3 (print)OAI: oai:DiVA.org:liu-142397DiVA, id: diva2:1153446
Conference
The 30th congress of the The International Council of the Aeronautical Sciences
Projects
OpenCPSAvailable from: 2017-10-30 Created: 2017-10-30 Last updated: 2023-01-19
In thesis
1. On Standardized Model Integration: Automated Validation in Aircraft System Simulation
Open this publication in new window or tab >>On Standardized Model Integration: Automated Validation in Aircraft System Simulation
2019 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Designing modern aircraft is not an easy task. Today, it is not enough to optimize aircraft sub-systems at a sub-system level. Instead, a holistic approach is taken whereby the constituent sub-systems need to be designed for the best joint performance. The State-of-the-Art (SotA) in simulating and exchanging simulation models is moving forward at a fast pace. As such, the feasible use of simulation models has increased and additional benefits can be exploited, such as analysing coupled sub-systems in simulators. Furthermore, if aircraft sub-system simulation models are to be utilized to their fullest extent, opensource tooling and the use of open standards, interoperability between domain specific modeling tools, alongside robust and automated processes for model Verification and Validation (V&V) are required.

The financial and safety related risks associated with aircraft development and operation require well founded design and operational decisions. If those decisions are to be founded upon information provided by models and simulators, then the credibility of that information needs to be assessed and communicated. Today, the large number of sensors available in modern aircraft enable model validation and credibility assessment on a different scale than what has been possible up to this point. This thesis aims to identify and address challenges to allow for automated, independent, and objective methods of integrating sub-system models into simulators while assessing and conveying the constituent models aggregated credibility.

The results of the work include a proposed method for presenting the individual models’ aggregated credibility in a simulator. As the communicated credibility of simulators here relies on the credibility of each included model, the assembly procedure itself cannot introduce unknown discrepancies with respect to the System of Interest (SoI). Available methods for the accurate simulation of coupled models are therefore exploited and tailored to the applications of aircraft development under consideration. Finally, a framework for automated model validation is outlined, supporting on-line simulator credibility assessment according to the presented proposed method.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2019. p. 76
Series
Linköping Studies in Science and Technology. Licentiate Thesis, ISSN 0280-7971 ; 1866
National Category
Embedded Systems
Identifiers
urn:nbn:se:liu:diva-162810 (URN)10.3384/lic.diva-162810 (DOI)9789179299293 (ISBN)
Opponent
Supervisors
Projects
Model Validation – from Concept to ProductOpen Cyber-Physical System Model-Driven Certified Development (OpenCPS).
Funder
Vinnova
Note

Ytterligare forskningsfinansiär: Saab Aeronautics

Available from: 2019-12-20 Created: 2019-12-19 Last updated: 2020-01-16Bibliographically approved
2. On the Realization of Credible Simulations in Aircraft Development: Efficient and Independent Validation Enabled by Automation
Open this publication in new window or tab >>On the Realization of Credible Simulations in Aircraft Development: Efficient and Independent Validation Enabled by Automation
2023 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Designing modern aircraft is not an easy task. Today, it is not enough to optimize aircraft subsystems at a subsystem level. Instead, a holistic approach is necessary whereby the constituent subsystems need to be designed for the best joint performance. The State-of-the-Art (SotA) in simulating and ex-changing simulation models is moving forward at a fast pace. As such, the feasible use of simulation models has increased and additional benefits can be exploited, such as analyzing coupled subsystems in simulators. Furthermore, if aircraft subsystem simulation models are to be utilized to their fullest extent, open-source tooling and the use of open standards, interoperability between domain specific modeling tools, alongside efficient and automated processes for model Verification and Validation (V&V) and credibility assessment are required.

The financial and safety related risks associated with aircraft development and operation require well founded design and operational decisions. If those decisions are to be founded upon information provided by models and simulators, then the credibility of that information needs to be assessed and communicated. Today, the large number of sensors available in modern aircraft enable model validation and credibility assessment on a different scale than what has been possible up to this point. This thesis aims to identify and address challenges to allow for automated, independent, and objective methods of integrating subsystem models into simulators while assessing and conveying the constituent models aggregated credibility.

The results of the work include a proposed method for presenting the individual models’ aggregated credibility in a simulator. As the communicated credibility of simulators here relies on the credibility of each included model, the assembly procedure itself cannot introduce unknown discrepancies with respect to the System of Interest (SoI). Available methods for the management, distribution, and accurate simulation of coupled models are therefore exploited and tailored to the applications of aircraft development under consideration. Finally, a framework for automated model validation is outlined and established that supports both on-line and on-line simulator credibility assessment.   

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2023. p. 341
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 2279
Keywords
Aircraft Vehicle Systems, Credibility Assessment, FMI, Interoperability, Modelica, Modeling and Simulation, Model integration, SSP
National Category
Embedded Systems
Identifiers
urn:nbn:se:liu:diva-191132 (URN)10.3384/9789179295981 (DOI)9789179295974 (ISBN)9789179295981 (ISBN)
Public defence
2023-03-03, ACAS, A-building, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Note

Funding agencies: INNOVA and Saab Aeronautics

Available from: 2023-01-19 Created: 2023-01-19 Last updated: 2023-01-19Bibliographically approved

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Citation style
  • apa
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  • Other style
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More languages
Output format
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