Modia - Equation Based Modeling and Domain Specific Algorithms

Elmqvist, Hilding; Otter, Martin; Neumayr, Andrea; Hippmann, Gerhard

doi:10.3384/ecp2118173

Cited by 8 publications

(16 citation statements)

References 13 publications

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“…This robot has a 5 DoF arm and was manufactured in the years 2010-2016. Elmqvist et al (2021) model the drive trains and controllers of the robot in Modia, and the 3D mechanics with Modia3D.…”

Section: Segmented Simulation and Collision Handlingmentioning

confidence: 99%

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Variable Structure System Simulation via Predefined Acausal Components

Neumayr,

Otter

2023

Linköping Electronic Conference Proceedings

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This article outlines a new approach of the experimental open-source modeling and simulation system Modia to simulate systems where the number of variables and equations can be changed after compilation and also during simulation, without having to re-generate and rec-ompile the code. Details are given for heat transfer in an insulated rod, where the discretisation of the rod is completely hidden from the symbolic engine. It is discussed how this approach could also be used in a future version of Modelica and/or FMI. Furthermore, this feature is also used in various variants to speed up collision handling in 3D mechanical systems. For example, by rigidly fixing an object after it has been gripped, with or without calculating the elastic response, and thereby dynamically changing the number of degrees of freedom.

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Section: Segmented Simulation and Collision Handlingmentioning

confidence: 99%

“…Modia (Elmqvist et al 2021) is an experimental, open source modeling and simulation system to develop new approaches to overcome the limitations of declarative, equation-based modeling languages such as Modelica (Modelica Association 2023). Modia is implemented with the powerful Julia programming language (Bezanson et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Variable Structure System Simulation via Predefined Acausal Components

Neumayr,

Otter

2023

Linköping Electronic Conference Proceedings

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“…The treatment below is focused on providing the information in a way that it can be used by models described with the Modelica language [4], FMI [1][2][3], SSP [25], Modia [26] or similar modeling approaches. Furthermore, not only physical/measured quantities are considered, but the same description form is also used to define requirements or specifications.…”

Section: Uncertaintymentioning

confidence: 99%

Towards Modelica Models with Credibility Information

Otter

Reiner²,

Tobolar³

et al. 2022

Electronics

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Modeling and simulation is increasingly used in the design process for a wide span of applications. Rising demands and the complexity of modern products also increase the need for models and tools capable to cover areas such as virtual testing, design-space exploration or digital twins, and to provide measures of the quality of the models and the achieved results. The latter is also called credible simulation process. In an article at the International Modelica Conference 2021, we summarized the state of the art and best practice from the viewpoint of a Modelica language user, based on the experience gained in projects in which Modelica models were utilized in the design process. Furthermore, missing features and gaps in the used processes were identified. In this article, new proposals are presented to improve the quality of Modelica models, in particular by adding traceability, uncertainty, and calibration information of the parameters in a standardized way to Modelica models. Furthermore, the new open-source Modelica library Credibility is discussed together with examples to support the implementation of credible Modelica models.

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“…In other words, the translation process from an acausal description based on equations to a causal representation acceptable for a solver is similar to that of a typical Modelica Compiler. Modia.jl [2,26] is another framework that extends the Julia language with capabilities for acausal modeling. Syntactically, it is closer to Modelica when compared to the language defined by MTK.…”

Section: Equation-based Modeling In Juliamentioning

confidence: 99%

A Modular, Extensible, and Modelica-Standard-Compliant OpenModelica Compiler Framework in Julia Supporting Structural Variability

2022

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Nowadays, industrial products are getting increasingly complex, and time-to-market is significantly shorter. Modeling and simulation tools for cyber-physical systems need to keep up with the increased complexity. This paper presents OpenModelica.jl, a modular and extensible Modelica compiler framework in Julia targeting ModelingToolkit.jl and supporting Variable Structured Systems. We extended the Modelica language with three new operators to support continuous-time mode-switching and reconfiguration via recompilation at runtime. Therefore, our compiler supports the Modelica language and variable structure systems via the aforementioned extensions. To our knowledge, there are no other Modelica tools available that support both standard Modelica and variable structure systems. We evaluated our framework using a standardized benchmark suite, in terms of simulation, compilation and recompilation performance. The results concerning compilation and simulation time performance were compared with the results of running the existing OpenModelica compiler with the same set of models. A custom benchmark was devised to estimate the cost in terms of recompilation when simulating variable structure systems. The performance experiments showed that OpenModelica.jl is currently about four times slower in terms of compilation time when compiling a transmission line model with tens of thousands of equations and variables. The difference in simulation performance between the two compilers was negligable. Furthermore, the impact of recompilation during the simulation was usually small compared with the simulation time for long simulations. The results are promising for a prototype, and we outline approaches to further improve both compilation and simulation performance as future research.

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Modia - Equation Based Modeling and Domain Specific Algorithms

Cited by 8 publications

References 13 publications

Variable Structure System Simulation via Predefined Acausal Components

Variable Structure System Simulation via Predefined Acausal Components

Towards Modelica Models with Credibility Information

A Modular, Extensible, and Modelica-Standard-Compliant OpenModelica Compiler Framework in Julia Supporting Structural Variability

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