FMI for Co-Simulation of Embedded Control Software

Abstract

Increased complexity of cyber-physical systems withinthe maritime industry demands closer cooperation be-tween engineering disciplines. The functional mockupinterface (FMI) is an initiative aiding cross-discipline in-teraction by providing, a widely accepted, standard formodel exchange and co-simulation. The standard is sup-ported by a number of modelling tools. However, to im-plement it on an existing platform requires adaptation.This paper investigates how to adapt the software of anembedded control system to comply with the FMI forco-simulation standard. In particular, we suggest a wayof advancing the clock of a real time operating system(RTOS), by overwriting the idle thread and waiting fora signal to start execution until return to idle. This ap-proach ensures a deterministic and temporal executionof the simulation across multiple nodes. As proof ofconcept, a co-simulation is conducted, showing that thecontrol system of an SCR (selective catalyst reduction)emission reduction system can be packed in a functionalmockup unit (FMU) and co-simulated with a physicalmodel, built in Ptolemy II. Results show that FMI can beused for co-simulation of an embedded SCR control soft-ware and for control software development. FMI for Co-Simulation of Embedded Control Software.