When different simulation units are coupled together there are different choices to take, in particular regarding the granularity of such a co-simulation. When prototyping systems, it is typically favourable to get an initial idea of how a collection of simulation units work together without spending too much time setting up the orchestration. However, the granularity of such a simulation may be far away from what is needed in relation to the purpose of the simulation. In order to enable more flexibility and control over the co-simulation it is necessary to be able to steer the orchestration in a more detailed manner. This paper presents an open source co-simulation orchestration engine based on the Functional Mockup Interface standard but with a Domain Specific Language (DSL) enabling detailed control between the individual simulation units. The same tool can thus be used right out of the box for low-granularity co-simulation, and for high-granularity simulation the DSL enable a significant flexibility.

In this work, we present the initial steps in the development of a digital twin of the agricultural autonomous vehicle, Robotti. A model of the vehicle dynamics is initially developed in the open-source multi-physics code, Chrono, and then wrapped as a Functional Mock-up Unit. We provide an overview of the envisioned digital twin system and a description of currently implemented features. The dynamic system of the vehicle chassis is characterised by the implementation of a revolute joint that ensures wheel–surface contact in uneven terrain. The vehicle dynamics model is applied for testing two scenarios describing the loads on the vehicle as a consequence of this mechanism. Finally, we give pointers to future work on modelling the Robotti and the establishment of a digital twin.