Download - 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)
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The problem, motivating the work is …… that injuries and damages appear in secondary events in multiple event accidents.
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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
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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
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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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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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1st MSc thesis
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Result of 1st MSc thesis
11
Research project will use simulatorfor verification
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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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Evaluation, p1(4)
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■ PIT manoeuvre■ Built‐in actuator■ Simulator SIM4■ Kick plate
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Result of 1st MSc thesis
20
Research project will use simulatorfor verification
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2nd MSc thesis
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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))
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2 Simulators used
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Chalmers “preparation simulator”
VTI advanced simulator (SIM4)
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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.
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2
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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.
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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
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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.
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Example of “Unprepared driver test”
Impact case 1
With =
Without =
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Longitudinal and Lateral displacement
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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=
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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))
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Next steps within Research Project
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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))