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The landscape of tools available for model-based development of Cyber-Physical Systems (CPSs) is vast, encompassing numerous specialized tools designed to support models at the component-level. In reality, the different parts of the system represented by these component-level models are often physically tightly coupled and interdependent, and the models themselves are subject to change and evolve over time. However, due to the lack of interoperability between tools it is often challenging to integrate component-level models into larger system simulations and to support model evolution across the entire product lifecycle. In order to streamline the system development process and allow for seamless integration of models and a variety of development tools, a comprehensive integrated model-based development environment is required. To address these challenges, this thesis contributes a model-based tool integration approach and an ontology-driven automated traceability method that utilizes a standardized integration convention, language-neutral model transformation technology, and co-simulation technique to integrate several tools for CPSs development as well as to automatically establish and maintain traceability between heterogeneous artifacts created throughout the product development lifecycle. The applicability, validity, and usefulness of these approaches and the developed prototypes are demonstrated through industrial-relevant use case examples. In particular, the main contributions presented in this thesis are summarized as follows: Design, development, and validation of an ontology-driven approach for multidisciplinary collaborative modeling and traceability support throughout the development process for CPSs; Design, development, and validation of a general approach for modeling a composite model containing several tool-specific simulation component-level models which can be integrated, connected, and simulated using the Transmission Line Modeling (TLM) co-simu, Funding agencies: The research presented in this thesis has been supported by Vinnova in the ITEA2 MODRIO, OPENCPS, and EMPHYSIS projects, by EU in the H2020 INTO-CPS project and, by the CleanSky Joint Undertaking project PyModSimA (JTI-CS-2013-2- SGO-02-064). Support from the Swedish Government has also been received from the ELLIIT project, and the Swedish Strategic Research Foundation (SSF) in the Proviking EDOP project. The Open Source Modelica Consortium supports the continuous development of the OpenModelica framework.

In the field of model-based design of Cyber-Physical Systems (CPS), seamless traceability of the process, from requirements to models to simulation results, is becoming increasingly important. It can be used to support several activities such as variant handling, impact analysis, component reuse, software maintenance and evolution, verification, and validation. Despite the fact that the relevance of traceability in the model-based design of CPSs is well known, current tools that support traceability management are inadequate in practice. The lack of comprehensive whole-lifecycle systems engineering support in a single tool is one of the main causes of such ineffective traceability management, where traceability relationships between artifacts are still manually generated and maintained. This paper aims at presenting an approach and a prototype for automatically generating and maintaining the appropriate traceability links between heterogeneous artifacts ranging from requirement models, through design models, down to simulation and verification results throughout the product life cycle in model-based design of CPSs. A use case study is presented to validate and illustrate the proposed method and prototype., Funding Agencies|Swedish Government; European Union in the H2020 INTO-CPS project; Vinnova in the ITEA OPENCPSVinnova; EMBRACE project; Open Source Modelica Consortium

OpenModelica is a unique large-scale integrated open-source Modelica- and FMI-based modeling, simulation, optimization, model-based analysis and development environment. Moreover, the OpenModelica environment provides a number of facilities such as debugging; optimization; visualization and 3D animation; web-based model editing and simulation; scripting from Modelica, Python, Julia, and Matlab; efficient simulation and co-simulation of FMI-based models; compilation for embedded systems; Modelica-UML integration; requirement verification; and generation of parallel code for multi-core architectures. The environment is based on the equation-based object-oriented Modelica language and currently uses the MetaModelica extended version of Modelica for its model compiler implementation. This overview paper gives an up-to-date description of the capabilities of the system, short overviews of used open source symbolic and numeric algorithms with pointers to published literature, tool integration aspects, some lessons learned, and the main vision behind its development., Funding agencies: Vinnova in the ITEA OPENPROD projectVinnova; Vinnova in the ITEA MODRIO projectVinnova; Vinnova in the ITEA OPENCPS projectVinnova; Vinnova in the ITEA EMPHYSIS projectVinnova; Vinnova in the ITEA EMBRACE projectVinnova; Vinnova RTISIM projectVinnova; Vin

A common situation in industry is that a system model (here a composite model) is composed of several sub-models which may have been developed using different tools. FMI is one important technology for exporting/importing models between tools and/or connecting them via co-simulation. TLM based modeling and co-simulation is another important technique for modeling, connecting, and simulation of especially mechanical systems, which is simple, numerically stable, and efficient. A number of tool-specific simulation models, such as Modelica models, SimuLink models, Adams models, BEAST models, etc., have successfully been connected and simulated using TLM based co-simulation. However, previously there was no general open source tool for creation, graphic editing, and simulation of composite models connected via FMI or TLM based co-simulation. In this paper we present a graphical composite model editor based on OpenModelica which is integrated with the OpenModelica and the SKF TLM co-simulation frameworks to support both FMI and TLM based composite model editing and simulation. The editor supports creating, viewing and editing a composite model both in textual and graphical representation. The system supports simulation of composite models consisting of sub-models created using different tools.

The Modelica and FMI tool ecosystem is growing each year with new tools and methods becoming available. The open Modelica standard promises portability but it is important to ensure that a certain model behaves the same in different Modelica tools or in a different version of the same tool. It is also very important (for model evolution) to check that a new version of the same model produces comparable results. Finally, it is desirable to verify that a model exported in FMU form from a Modelica tool gives exactly the same results as the original model. This paper presents a framework for automatic regression testing as part of PySimulator which provides an efficient and concise way of testing if a model or a range of models behaves in the same way in several tools or versions of a tool by checking that the results produced are essentially identical. The FMI standard has been adopted by many tool vendors and is growing in popularity each year. This paper proposes a concept for building and simulating a system made from connected FMUs generated by different tools. The FMUs for Co-Simulation can be connected together using a GUI. The system model built graphically in this way can be saved for later use or simulated directly inside PySimulator. Active development is going on to support simulation of connected FMUs for Model Exchange.