Use Case: Integrating Functional Mock-up Units for HIL Simulation

This use case example demonstrates how functional mock-up units (FMUs) from different vendors can be integrated to make one real-time-capable application for hardware-in-the-loop (HIL) simulation. This was performed jointly with Dassault Systèmes and ITI.

The Use Case

The demo system consists of an electronic stability program (ESP) ECU connected to a dSPACE SCALEXIO HIL system with dSPACE ControlDesk and MotionDesk for controlling and visualizing the simulation run, and dSPACE ConfigurationDesk for integrating the models into one application.
The objective was to replace some parts of the virtual vehicle simulation model in an existing ESP ECU HIL testing system with new ones developed according to a physical modeling (acausal) approach. 
The vehicle dynamics and environment model were modeled with dSPACE Automotive Simulation Models. The original engine and drivetrain model were replaced by real-time-capable C code FMUs based on the Functional Mock-up Interface for Co-Simulation 2.0, Release Candidate 1. The sample time of all the integrated model parts is 1 ms. 

The Workflow

The screenshot is an example of the interface of the drivetrain FMU provided by ITI. Model port blocks are used to create the ports representing the FMU interface in the Simulink model. This interface can be analyzed and connected via ConfigurationDesk.

ConfigurationDesk is the graphical configuration and implementation software for SCALEXIO hardware. The two FMUs are imported into ConfigurationDesk and integrated with the existing simulation model. This is done by connecting the FMU interfaces with the model port blocks created in Simulink to make one real-time-capable application. This overall simulation model is then downloaded onto the SCALEXIO HIL simulator. In this case model communication with Simulink is used to integrate the FMUs into the existing simulation model. Alternatively, an FMU could also be connected directly to I/O functions or to other FMUs, as well as to V-ECUs, in ConfigurationDesk.

ControlDesk is used to start and control the simulation run. The photorealistic experiment layouts give an impression of what the car dashboard will look like. 

All model variables and parameters, such as the yaw rate, brake pressure and velocity, are displayed and plotted in real time during the simulation run to give you constantly up-to-date information about what is happening.
This demo system tests the functionalites of an ESP ECU. The same simulation scenario – a car braking on a slippery road – is performed twice for comparison: once with the ESP ECU turned off and once with it turned on.

MotionDesk visualizes the simulation run so that you can see how the car is behaving. In the first simulation run with the ESP ECU turned off, the car starts to skid during braking and spins round.

With the ESP ECU turned on, the braking maneuver brings the car to a controlled stop.

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