Development of post impact control verification method in motion platform simulator and evaluation of post impact braking Transportforum 2013

1. Development of post impact control verification
method in motion platform simulator and
evaluation of post impact braking ,
Mathias Lidberg, Chalmers
(=stand‐in presenter for Bengt Jacobson, Chalmers, bengt.jacobson@chalmers.se, +46 31 772 1383)
Modified 2013‐01‐09 09:52 Jacobson, Post Impact Control verification methods in simulator slide 1

2. The problem, motivating the work is …
… that injuries and damages appear in secondary events in multiple event accidents.
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3. Threats in post (1st) impact motion
stand still VRUs
side objects outside road
outside road
side‐lane
side‐lane rear‐ meeting vehicles
coming vehicles
roll‐over
driver cannot
regain control
own‐lane rear‐ subject vehicle own‐lane
coming vehicles impacted here vehicles
Modified 2013‐01‐09 09:52 Jacobson, Post Impact Control verification methods in simulator slide 4

4. This presentation…
…summarizes two MSc theses done within a research project “Post Impact
Stability Control”, in which Volvo Cars and Chalmers addresses the problem
PISC research project
2nd MSc thesis:
1st MSc thesis:
Result: Develop verification
What
Simulator method using Result:
equipment?
simulator! Method
Verification
of PISC
function
PISC
function
Develop a PISC function
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5. The problem to verify a PIC function, p1(2)
Main verification task:
“(Benefit – Drawback) > Required Number”
• Quantified “Required Number”
• Benefit (and Risk) is relative to a reference vehicle in
same situation.
• Measures to quantify the Benefit (and Risk), see later
slide.
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6. The problem to verify a PIC function, p2(2)
Problem space dimensions to cover:
• Vehicle states (x, y, , , , , ) before 1st impact
• Different 1st impact impulse magnitude, hit point at subject
vehicle and impulse direction
• Subject vehicle damages in 1st impact:
• HW (actuators, sensors, wheels)
• SW (deactivation of functions due to plausibility)
• Road and traffic surroundings
• Road friction/roughness
• Road edges, obstacles outside road
• Other road users
• Driver behaviour:
• during 1st impact (pedals, steering wheel, airbag, …)
• after 1st impact (pedals, steering wheel, including “driver‐over‐ride”)
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7. 1st MSc thesis
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8. Result of 1 st MSc thesis
Research project
will use simulator
for verification
11
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9. Different equipment alternatives
Evaluated:
• Precision Immobilization Technique (PIT) maneuvers
• Built‐in actuators
• Kick plate
• Driving simulator
• (+ some more, see MSc thesis report)
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10. ■ PIT manoeuvre
Evaluation, p1(4) ■ Built‐in actuator
■ Simulator SIM4
■ Kick plate
17
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11. Result of 1 st MSc thesis
Research project
will use simulator
for verification
20
Modified 2013‐01‐09 09:52 Jacobson, Post Impact Control verification methods in simulator slide 20

12. 2nd MSc thesis
21
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13. Result of 2 nd MSc thesis
• PIB function as reference for more advanced PIC
• 1st impacts (impulse, position, direction) relevant
from accident databases.
• Triggering of 1st impact in repeatable traffic
situations
• Set up with unprepared, prepared and passive
drivers
• (Evaluation of PIB function (out of scope for this presentation))
22
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14. 2 Simulators used
Chalmers
“preparation
simulator”
VTI advanced simulator (SIM4)
24
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15. Proposed benefit measures
• Measures:
1. Longitudinal distance: distance the car travels parallel to road after the impact
until stand‐still.
2. Lateral distance: lateral distance the car travels perpendicular to the road after
the impact until stand‐still.
3. Perpendicular lane crossing speed: speed, perpendicular to the road, at which
the car leaves the road after the impact.
4. Absolute lane crossing speed: absolute speed at which the car leaves the road
after the impact.
5. Maximum yaw angle: maximum yaw angle the car has after the impact.
4
subject vehicle
3 stand‐still here
subject vehicle
impacted here
2 5
1
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16. PIB definition
Overall purpose:
Decelerate and stop the car when the driver is not able to
do so. The steering is not actuated.
Triggering:
After a collision which induces a speed change higher than a certain threshold
(approx. triggering level for irreversible restraints), the PIB function is triggered and
decelerates the car to zero speed state and holds it stationary.
Actuation:
PIB brakes the car and forbids the driver to accelerate. For side and rear collisions:
≈4xABS.
Driver override:
PIB will be overridden by driver pressing hard on the acceleration pedal, without
pressing the brake pedal.
Within MSc thesis: Evaluated
Planned use in research project: Reference for PISC
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17. 4 different “1st impacts” proposed
• Selected as relevant from accident
database (GIDAS), meaning:
• frequent,
• detectable 1st impact and
• actuate‐able / controllable
1) 11 kN, 80 km/h
• Each specified by:
• impulse ( = force * time duration),
• hit point position and
• direction
Modified 2013‐01‐09 09:52 Jacobson, Post Impact Control verification methods in simulator slide 28

18. Proposed “Set ups”
3 different set‐ups were proposed and used.
• The overall purpose for all: to compare with and without the PIC function.
• 1st impact triggered on certain combination of vehicle states, e.g. when
vx>80 km/h AND within left lane.
The 3 different set‐ups were:
• Unprepared drivers
• Understand the driver response
• Order of with and without can influence driver’s response (“with, without, with” proposed)
• Prepared drivers (driver asked to keep on road and stop vehicle a.s.a.p.)
• Seen as one extreme of driver behaviour
• Passive drivers (feet released from pedals, hands released from steering
wheel (can be done in pure simulation!))
• Seen as “the other” extreme of driver behaviour
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19. Example of “Unprepared driver test”
With =
Impact case 1
Without =
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20. Longitudinal and Lateral displacement
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21. Comparisons between “prep‐simulator”
and advanced simulator
prep‐simulator=
advanced simulator=
• Same “pattern”, but different levels.
• Maybe a tendency that vehicle less controllable in “prep‐simulator”.
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22. Result of 2 nd MSc thesis
• PIB function as reference for more advanced PIC
• 1st impacts (impulse, position, direction) relevant
from accident databases.
• Triggering of 1st impact in repeatable traffic
situations
• Set up with unprepared, prepared and passive
drivers
• (Evaluation of PIB function (out of scope for this presentation))
37
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23. Next steps within Research Project
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24. Next steps (spring/summer 2013):
• Code 1‐2 PISC functions:
• Advanced PISC controller (using “Quasi‐Linear Optimal
Control”).
• A simpler PISC, “on‐top of ESC” or “on top of PIB”.
• Concepts are developed, but integration with ABS & ESC
& Steering Assistance controllers needs to be done.
• Carry out clinics with those and compare PISC functions
with a reference vehicle (with PIB). Use methods developed
in 2ns MSc thesis.
• (Dissertation planned October 2013 (PhD candidate Derong Yang))
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25. Thanks to:
• Chalmers MSc thesis
• KTH MSc thesis
• SAFER
• VCC
• VTI
Thank you for your attention!
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