Simulation-based design of a handover function

Authors

L.-C. Schudi, M. Hermann – IPG Automotive GmbH

Summary

Partially automated driving (AD) functions require human intervention at certain points in time. Here, control and thus responsibility is handed over from the system to the driver. This represents a weakness of AD functions of a certain level caused by factors such as a lack of situational awareness by the driver. If the driver does not comply with a handover request, the AD function must perform a maneuver to minimize the risk. Due to the inclusion of the driver in the handover request, an extensive testing effort is necessary to validate such systems. To test these functions as soon as possible in the development process simulation is used throughout the complete process with differing test focus in the development stages.

To enable integrated testing and validation, including the analyses of safety, usability and comfort of the functions, suitable test procedures exist for all development phases: model-in-the-loop (MIL), software-in-the-loop (SIL), hardware-in-the-loop (HIL), driver-in-the-loop (DIL) and vehicle-in-the-loop (VIL). MIL, SIL and HIL have in common that the system under test is integrated into a virtual vehicle either as a software model or as a real component and tested in simulation and that no real driver is in the loop yet. DIL enables the real driver to control a simulated vehicle in the simulated environment himself using a driving simulator. They can help to significantly reduce the gap between HIL and conventional test drives and to gain important insights into system characteristics and vehicle behavior at a much earlier time. Using VIL, the physical sensor signals of a real vehicle are replaced by simulated ones to emulate a virtual environment for the vehicle and the driver can experience the function in a real vehicle on a proving ground, thus adding the interaction with the designated human-machine interface (HMI).

This paper describes how each of these methods offers different advantages com-pared to the real driving test. Especially DIL and VIL testing enable a subjective feel of the expected driving experience. Simulation thus enables to safely test and optimize the behavior of handover functions, even at early stages of the development process.