Hybrid simulation using implicit solver coupling with HLA and FMI

Hybrid systems such as Cyber Physical System (CPS) are becoming increasingly popular, mainly due to the involvement of information technology in different aspects of life. For analysis and verification of hybrid system models, simulation is used extensively. As parts of a common hybrid system may belong to different domains of study, it is sometimes beneficial to use specialized simulation packages (SPs) for each domain. In this case, parts of a system are simulated in different SPs. The idea may seem simple, but coupling more than one simulation component presents challenges related to numerical stability. The presented article suggests an implicit solver coupling technique enhanced to facilitate simulation of hybrid models using multiple simulation components. The technique is developed using two of the most popular simulation interoperability standards, namely, the High Level Architecture and the Functional Mock-up Interface. By using these standards, the developed algorithm will be useful for a large number of practitioners and researchers. The developed algorithm is described using a generic distributed computation model, which makes it reproducible even without using the standards. For the verification of results, the algorithm is tested on two case studies. The results are compared to a monolithic simulator and the proximity of results initiates the validity of the developed algorithm.