Solving time-dependent coupled systems through FMI co-simulation and BPMN process orchestration

In this work we present a synergic integration of the Functional Mock-Up Interface (FMI) and Business Process Model and Notation (BPMN) standards aimed at managing coupled system simulations. The expressiveness of the BPMN diagrams enabled us to define the relationship between the involved systems and guarantees a one-to-one correspondence with an XML file which is the starting point for the automation and the Functional Mock-Up Unit (FMU) orchestration. For that purpose we describe a typical (although non-standard) master algorithm governing the time-dependent simulation of a coupled system. The dependency diagram and the execution algorithm rely on a very limited set of BPMN extension elements since the standard already offers a range of basic elements which facilitate the implementation of a specific execution environment for FMI co-simulation. This study explores the theoretical issues behind the FMI-BPMN integration and the practical implementation problems. The final result is the complete BPMN diagram for the master algorithm, fully interfaced with the FMI functions of the FMU execution blocks.