Abstract
Co-simulation is integral to the model-based systems engineering process for cyber-physical systems (CPS). Co-simulation bridges the gap between engineering disciplines and organiza- tions, enabling engineers to assemble opaque heterogeneous models into a single simulation that captures the entire system. Specifically, co-simulation provides a means to simulate the behav- ior of a system composed of subsystems developed in different formalisms and tools to foster collaboration between specialized organizations.
Interoperability between different models and tools is achieved by encapsulating the sub- systems in a standardized interface, such as the Functional Mock-up Interface (FMI) standard. The FMI standard allows a co-simulation framework to combine the subsystems, packaged as Functional Mock-up Units (FMUs), into a single simulation by orchestrating the simultaneous execution of the FMUs according to an orchestration algorithm. The orchestration algorithm outlines how stimuli are exchanged between the subsystems to coordinate their simulation and represent the behavior of the composed system.
Unfortunately, the FMI standard provides minimal guidance on how a collection of FMUs should be simulated. As a result, the accuracy and reliability of a co-simulation result is limited, and practitioners are sometimes forced to rely on heuristics and trial and error to achieve accurate simulation results.
This thesis seeks ways to improve FMI-based co-simulation. Specifically, this thesis presents a multi-faceted approach that includes semantic studies of the FMI standard, formal modeling of co-simulation algorithms, and the development of open-source tools for synthesizing and verifying orchestration algorithms for FMI-based co-simulation. Finally, the project includes the develop- ment of an open source co-simulation framework that integrates the developed tools to enable co-simulation practitioners with different needs and levels of expertise to perform FMI-based co-simulations.
Interoperability between different models and tools is achieved by encapsulating the sub- systems in a standardized interface, such as the Functional Mock-up Interface (FMI) standard. The FMI standard allows a co-simulation framework to combine the subsystems, packaged as Functional Mock-up Units (FMUs), into a single simulation by orchestrating the simultaneous execution of the FMUs according to an orchestration algorithm. The orchestration algorithm outlines how stimuli are exchanged between the subsystems to coordinate their simulation and represent the behavior of the composed system.
Unfortunately, the FMI standard provides minimal guidance on how a collection of FMUs should be simulated. As a result, the accuracy and reliability of a co-simulation result is limited, and practitioners are sometimes forced to rely on heuristics and trial and error to achieve accurate simulation results.
This thesis seeks ways to improve FMI-based co-simulation. Specifically, this thesis presents a multi-faceted approach that includes semantic studies of the FMI standard, formal modeling of co-simulation algorithms, and the development of open-source tools for synthesizing and verifying orchestration algorithms for FMI-based co-simulation. Finally, the project includes the develop- ment of an open source co-simulation framework that integrates the developed tools to enable co-simulation practitioners with different needs and levels of expertise to perform FMI-based co-simulations.
| Original language | English |
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| Publisher | |
| Publication status | Published - Oct 2023 |