Repeatable Simulation for Highly Automated Driving Development and Testing

The development and testing of automated driving functions in the real world is costly and time-consuming. For this reason, software for automated driving is at first developed and tested in a virtual environment. The provision of the virtual environment requires the coupling of several simulation tools and models. The result is a co-simulation with a feedback loop from the automated driving function to the virtual environment, that does not necessarily exhibit deterministic behavior. However, determinism is a desirable property for developers to be able to analyze the automated driving function and for testers to be able to implement test automation. This paper identifies sources of non-determinism in co-simulation setups for automated driving and proposes a master-less coupling approach that allows repeatable executions. The results are demonstrated using an exemplary driving scenario and compared to a traditional coupling method that uses physical clock synchronization. The presented approach adds some overhead to the simulation modeling and execution, but ensures repeatable simulation results in any case.