Over the past decade, a tool-independent standard for model interoperability and exchange, the Functional Mock-Up Interface (FMI) has gained traction in the simulation software world. The FMI standard enables seamless interoperability for simulation software solutions. Using the standard, one can connect models from different software tools and create virtual system prototypes system that best suits a particular simulation or test intent.
When a software tool conforms to the FMI standard, users can import or export a Functional Mock-Up Unit (FMU) which is a model representation that conforms to the FMU standard. The underlying modelling detail is abstracted out in the FMU. It is simply a zip file with a XML representation of the model structure. This abstract representation of the model has several advantages. It primarily alleviates any proprietary concerns since the underlying modelling techniques and system information are not exposed. It also aids the model’s usage without any knowledge of the modelling software in which it was created.
Adams and its users have embraced the FMI standard, and it’s been leveraged for a wide variety of different applications such as Hardware in the loop (HIL) testing. The Adams model is ported to the HIL platform using the FMI standard. In Adams 2021, there is a significant enhancement to FMUs from Adams Car models. Previously, once a FMU was exported out, there was no way to change either the vehicle variant or the vehicle event that was packaged in the FMU. Only changes to the vehicle model parameters such as mass and hardpoint properties, property files, parameter and design variables were possible. Now in this release, Adams Car can also expose assembly variants and events as fixed model parameters, so that they can be changed by the consumer of the FMU, for example a user running models on a Real Time operating system installed on a HIL platform.
This is achieved by invoking an option to expose the variants and events in the Adams FMU and making them available for changes by the FMI master. The variants and events become available as design variables.
For example, changing the default from 1.0 to 2.0 instructs Adams Car to run the second event in the FMU.
This new functionality will allow users to package a set of variants and events with an Adams Car FMU and switch between them in online applications, such as on a HIL test bench, without having to regenerate the FMU.