Generic Crash Pulses Representing Future Accident Scenarios of Highly Automated Vehicles
Abstract:
Assessment of crashworthiness of autonomous vehicles (AVs) must be carried out
for future crash scenarios, as not all crashes will be avoidable. Representative
crash pulses for AVs are needed to evaluate conceptual design restraint systems
of those vehicles.
Within this study, generic crash pulses for crash scenarios expected to be
relevant for AVs were generated based on a set of vehicle-to-vehicle structure
simulations with current European sedan cars. These crash scenarios included one
Straight Crossing Path (SCP) and two Left Turn Across Path Opposite Direction
(LTAP OD) scenarios with varying initial velocities and weight ratios of the
crash opponents to obtain different crash configurations. Additionally,
full-width frontal simulations with 40 kph and 56 kph were included as a
reference. The acceleration signals obtained from the individual simulations
were approximated by Legendre polynomials. A prediction model was created for
each crash configuration based on a set of three to four pulses to provide a
generic crash pulse for each investigated crash configuration. The prediction
quality of the model was tested against simulations with freely available finite
element (FE) models.
A number of 20 or 60 basis functions of Legendre polynomials was needed to
approximate the obtained velocity or acceleration signals with a correlation of
at least 0.9. The obtained prediction model for each crash configuration was
able to provide good predictions for heading direction when simulations were
within the training data. Approximating velocities and differentiation to derive
acceleration turned out to be the better option than approximating the
acceleration directly. Eventually, five crash configurations were proposed for
future investigations. The derived generic crash pulses capture a range of
loading severities, directions, and stiffness of current heavy sedan cars. The
pulses can be used for sled simulations to evaluate restraint systems in
conceptual studies when no vehicle-specific crash pulses are available.