Integration Testing of Networked Driver Assistance Functions with Hardware-in-the-Loop for the New Passat CC
The new Passat CC is full of advanced technologies with its innovative driver assistance systems like the "Park Assist" (PLA), the active cruise control (ACC) with environment observance system "Front Assist" and the "Lane Assist" (HCA). The integration of the networked driver assistance functions in the full vehicle was systematically supported by the consistent use of the HIL simulation and a maneuver and event based test methodology.
Sven-Oliver Mueller, team leader for the division engine-HIL at VW, presents in his speech a HIL integration test bench which is used to test the driver assistance systems. In this test bench 18 powertrain ECUs are integrated. Thus it is possible to functionally study the driver assistance systems in interaction with engine, gearing, braking and steering ECUs. The systems communicate via the CAN bus and it is controlled that the interaction between the systems performs, corresponding to the specifications, without faults.
As driver assistance systems observe the environment with cameras and sensors, the coupling of the systems with the simulation's virtual environment represents a special challenge. The presented HIL system at VW unifies different solutions for the integration of the systems. Thus the ACC's servo loop is closed by the CAN bus, at the HCA a motor, which shows the online animations of the test scenarios, serves as an optical interface. On the contrary, the PLA control unit communicates via ultrasound with the model of the parking sensors. The test scenarios, composed of the dynamic elements of driver, vehicle, road and traffic, are exactly reconstructed with CarMaker. Hence it is possible to analyse the systems' interaction under realistic, and at the same time, reproducible application conditions.
The integration tests on the HIL test bench are a significant support of the release process at VW. The systems can be verified both time and cost efficiently without any risk to the human being and physical objects. As domain-wide functions grow, especially with the implementation of driver assistance systems, the goal is to unify the divisions drivetrain and comfort on one HIL test bench in the near future. Regarding the rapid enhancement of the driver assistance systems, the implementation of new technologies, like the sensor fusion and modern camera systems on the HIL test bench, will pose ever new challenges.
