Development of Chassis Software with Virtual Prototypes

 Co-Simulation of CarMaker with Synopsys virtual ECU

The challenges in the development of a new electric vehicle at AUDI demand more “virtual development” to reduce the number of prototype vehicles and to improve the collaboration within AUDI and with Tier-1 suppliers. Furthermore, the new E/E-architecture requires a higher level of accuracy at an early stage in the development process of software functions. To meet these requirements, a new SIL simulation environment using IPG CarMaker was developed at AUDI.

It consists of a co-simulation of the Carmaker vehicle model with Synopsys (former QTronic) Silver vECU tool. The modeling process is synchronized with the vehicle milestones to create synergies between SIL and HIL testing by using the same models in various use cases.

The modular concept of the vehicle model allows using the IPG standard models for fast-running simulations (with normal accuracy) while custom plug-ins or fmu models provided by suppliers are integrated for highly detailed analysis of special topics. While the vehicle model in CarMaker holds all the hardware models, the software models (vECU) along with a rest bus model are simulated in Synopsys Silver. The focus of this architecture is to have as few signals on the co-simulation interface as possible to increase simulation performance.

To prove the validity of the vehicle model, the parametrization process and the modeling of the plug-ins were validated with extensive vehicle measurements. In several iteration loops the scope was moved from single components to systems and finally to the entire vehicle. Consequently, the requirements known from international ISO norms are met by the vehicle model, enabling it to be a “virtual twin” for chassis software development.

To further increase the modularity of different simulation environments, the OpenXWD architecture is used to integrate validated powertrain models for fuel consumption. This way, CarMaker can be used for use cases other than vehicle dynamics simulation.

This tool chain is currently used in various use cases at AUDI from SW development, functional safety testing, pre-calibration, and SW testing. One of the main benefits of the simulation environment is that it is not confined to specialized simulation departments but can easily be used by engineers with little previous simulation experience on “normal” desktop PCs. Another advantage is the connectivity to existing MCD tools like Vector Canape, which enables the re-use of existing layouts etc., and well-kown standards such as A2L or DCM files.

The tool chain IPG CarMaker and Synopsys Silver have proven to be easy-to-use tools, enabling AUDI to strengthen the “virtual development” of chassis software functions.