The FMI++ library: A high-level utility package for FMI for model exchange

Abstract

The success and the advantages of model-based design approaches for complex cyber-physical systems have led to the development of the FMI (Functional Mock-Up Interface), an open interface specification that allows to share dynamic system models between different simulation environments. The FMI specification intentionally provides only the most essential and fundamental functionalities in the form of a C interface. On the one hand, this increases flexibility in use and portability to virtually any platform (even embedded control systems). On the other hand, such a low-level approach implies several prerequisites a simulation tool has to fulfil in order to be able to utilize such an FMI component, for instance the availability of adequate numerical integrators. The FMI++ library presented here addresses this problem for models according to the FMI for Model Exchange by providing high-level functionalities, especially suitable for but not limited to discrete event simulation tools. The capabilities of this approach are illustrated with the help of several applications, where the FMI++ library has been successfully deployed. This approach intends to bridge the gap between the basic FMI specifications and the typical requirements of simulation tools that do not primarily focus on continuous time-based simulation. In other words, this enables such models to be used as de-facto stand-alone co-simulation components.