Session 27 Bengt Jacobson

Modified 2013‐01‐09 09:52 Jacobson, Post Impact Control verification methods in simulator slide 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, [email protected], +46 31 772 1383)


The problem, motivating the work is …… that injuries and damages appear in secondary events in multiple event accidents.


Threats in post (1st) impact motion

stand stillside objectsoutside road

VRUs outside road

roll‐over

own‐lane vehicles

own‐lane rear‐coming vehicles

side‐lane rear‐coming vehicles

driver cannot regain control

side‐lane meeting vehicles

subject vehicle impacted here


PISC research project

This presentation…

1st MSc thesis:What

equipment?

2nd MSc thesis:Develop verification

method using simulator!

Verification of PISC function

Result: Simulator

PISC functionDevelop a PISC function

Result: Method

…summarizes two MSc theses done within a research project “Post Impact Stability Control”, in which Volvo Cars and Chalmers addresses the problem


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.


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”)


1st MSc thesis


Result of 1st MSc thesis

11

Research project will use simulatorfor verification


Different equipment alternatives

Evaluated:

• Precision Immobilization Technique (PIT) maneuvers• Built‐in actuators• Kick plate• Driving simulator

• (+ some more, see MSc thesis report)


Evaluation, p1(4)

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■ PIT manoeuvre■ Built‐in actuator■ Simulator SIM4■ Kick plate


Result of 1st MSc thesis

20

Research project will use simulatorfor verification


2nd MSc thesis


Result of 2nd MSc thesis

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• 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))


2 Simulators used

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Chalmers “preparation simulator”

VTI advanced simulator (SIM4)


Proposed benefit measures

subject vehicle impacted here

subject vehicle stand‐still here

• 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.

1

2

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5


PIB definition

Within MSc thesis: EvaluatedPlanned use in research project: Reference for PISC

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.


4 different “1st impacts” proposed

1) 11 kN, 80 km/h

• Selected as relevant from accident database (GIDAS), meaning:• frequent, • detectable 1st impact and • actuate‐able / controllable

• Each specified by:• impulse ( = force * time duration),• hit point position and • direction


Proposed “Set ups”

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

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.


Example of “Unprepared driver test”

Impact case 1

With =

Without =


Longitudinal and Lateral displacement


Comparisons between “prep‐simulator” and advanced simulator

• Same “pattern”, but different levels.• Maybe a tendency that vehicle less controllable in “prep‐simulator”.

prep‐simulator=advanced simulator=


Result of 2nd MSc thesis

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• 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))


Next steps within Research Project


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))


Thanks to:• Chalmers MSc thesis• KTH MSc thesis• SAFER• VCC• VTI

Thank you for your attention!

Session 27 Bengt Jacobson

Automotive

Transcript of Session 27 Bengt Jacobson