Automatic parallelization of multi-rate fmi-based co-simulation on multi-core

International audienceCo-simulation refers to simulating a complex system using several coupled numerical models. Engineersdefine the rate of data exchange between the models by setting communication steps. FMI is a standardizedinterface which easily allows coupling and co-simulation of numerical models. The RCOSIM approachallows the parallelization on multi-core processors of co-simulations using the FMI standard. In this paper,we tackle the limitations of this approach. First, we extend the co-simulation to multi-rate, i.e. with differentcommunication steps. We present graph transformation rules and an algorithm that allow the execution ofeach model at its respective rate while ensuring correct data exchange between models. Second, we presentan acyclic orientation heuristic for handling mutual exclusion constraints between operations that belong tothe same model due to the non-thread-safe implementation of FMI. We evaluate the obtained speedup on amulti-core processor and the effect on the accuracy of the numerical results

Scheduling Real-time HiL Co-simulation of Cyber-Physical Systems on Multi-core Architectures

International audienceWhen designing complex cyber-physical systems, engineers have to integrate numerical models from different modeling environments in order to simulate the whole system and estimate its global performances. Co-simulation refers to such joint simulation of heterogeneous models. If some parts of the system are physically available, it is possible to connect these parts to the co-simulation in a Hardware-in-the-Loop (HiL) approach. In this case, the simulation has to be performed in real-time where models execution consists in periodically reacting to the real (physically available) components and providing periodic output updates. This paper deals with the parallelization and scheduling of real-time Hardware-in-the-Loop co-simulation of numerical models on multi-core architectures. A method for defining real-time constraints that have to be met is proposed. Also, an ILP formulation as well as a heuristic are proposed to solve the problem of scheduling the co-simulation on a multi-core architecture while satisfying the previously defined real-time constraints. The proposed approach is evaluated for different sizes of co-simulations and multi-core processors