Univ logo

Altruistic Decision Makerfor

Controlled Collision Mitigation

James E. TrollopeProfessor Keith J. Burnham

Control Theory and Applications Centre (CTAC)Coventry University

UKACC PhD Presentation Showcase

Univ logo

Linear (nearly!) relationship between maximum vehicle collision energy capacity and corresponding vehicle mass

Occupants within larger vehicle experience lower decelerations

European new car assessment programme (Euro NCAP)

Relationship due to greater deformation lengths of larger vehicles UKACC PhD Presentation Showcase Slide 2

Motivation for research

Vehicle mass (kg)500 1000 1500 2000

Max

imum

veh

icle

col

lisio

n en

ergy

cap

abilit

y (k

J)

50

100

150

200

Vehicle mass (kg)500 1000 1500 2000O

ccup

ant a

vera

ge d

ecel

erat

ion(

ms-2

)

170

180

190

200

210

220∆𝐸𝑚𝑎𝑥𝑎

𝑚𝑎≈∆𝐸𝑚𝑎𝑥𝑏

𝑚𝑏

e.g.

Vehicle mass (kg)500 1000 1500 2000Ma

ximum

vehic

le colli

sion e

nergy

capabi

lity (kJ

)

50

100

150

200

Vehicle mass (kg)500 1000 1500 2000Oc

cupa

nt a

vera

ge d

ecele

ratio

n(m

s-2)

170

180

190

200

210

220

Vehicle mass (kg)500 1000 1500 2000O

ccup

ant a

vera

ge d

ecel

erat

ion(

ms-2

)

170

180

190

200

210

220

Vehicle mass (kg)500 1000 1500 2000O

ccup

ant a

vera

ge d

ecel

erat

ion(

ms-2

)

170

180

190

200

210

220

Univ logo UKACC PhD Presentation Showcase Slide 3

Motivation for research Two colliding masses

Principle of Conservation of Energy and Momentum Distribution of collision energy based on vehicle mass ratio

∆ 𝑬𝒎𝒂𝒙𝒂=𝟒𝟓𝒌𝑱

= 228kJ𝒎𝒂=𝟓𝟎𝟎𝒌𝒈

35.76 (80 = 0 > 51 <

Issues with 4 : 1 ratio needs addressing

Univ logo

Active buckling control Controlled point of failure of

structure, denoted - altered using actively controlled materials

Altering apportions energy each vehicle absorbs

UKACC PhD Presentation Showcase Slide 4

Reversal of the problem

Altruistic approach Inspired by nature - ‘devotion

to the good of others’

Host Partner

Care of partner vehicle and

passengers – larger vehicle ‘cushions’ smaller

Univ logo UKACC PhD Presentation Showcase Slide 5

Controlled collision approach (International Patent Application No: PCT/GB2014/053442)

Dominant vehicle Partner vehicle Host (larger)

vehicle

Information transferred via V2V communication

Known, predicted and

estimated properties of

partner vehicle

Collision properties determined for host and partner vehicle

Known, predicted and

estimated properties of host vehicle

n-dimensional look-up table interpolated using fuzzy logic algorithm of host

vehicle

Altruistic decision maker algorithm of

host vehicleActive vehicle body structure algorithm of host vehicle

 

Active vehicle body structure algorithm of

partner vehicle  

Univ logo UKACC PhD Presentation Showcase Slide 6

Altruistic decision maker algorithm N-dimensional look-up table (NDLT)

NDLT contains pre-emptive values of desired collision energy corresponding to host and partner vehicle

Collision properties determined

Decision making

Algorithm 1

Reverse mass ratio

Decision making

Algorithm 2

Refinements

Decision making

Algorithm 3

Occupant properties considered

Step 1: NDLT initially interpolated using fuzzy

logic Step 2: NDLT refined interpolation using fuzzy

logic

Fuzzy logic used to interpolate between values and select/refine best estimate

Collision properties determined for active vehicle body structure

Univ logo

Hence, controlling eigenvalue alters energy absorbed by a vehicle

UKACC PhD Presentation Showcase Slide 7

Active vehicle body structure algorithm Developed of collision model

Finite element analysis (FEA) models used as benchmark

Tuneable piecewise linear model

Bilinear model fitting technique

Deformation (m)0 0.1 0.2 0.3 0.4 0.5

Forc

e (N

)

105

0

2

4

6

8Piecewise linear fitFEA original data Bilinear fit

Controlling structure failure point Modelled as lumped mass model

Formulation centres around generalised eigenvalue problem

Eigenvalue is proportional to buckling load

Partner (small) vehicle

Deformation (m)0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Fo

rce

(kN

)

0

100

200

300

400

500

600

Passive collisionAlgorithm 4.1Algorithm 4.2Algorithm 4.3

Host (large) vehicle

Univ logo

Trollope’s rule Ascertains just how much altruism could be anticipated for a

vehicle to give and/or receive

UKACC PhD Presentation Showcase Slide 8

Ethical considerations

Trollope’s altruistic index Provides a measure of how much the energy distribution ratio

can be safety adjusted Aggressivity/vulnerability index

Further useful measure is that of an aggressiveness/vulnerability index (AVI)

The above prompts the need for new crashworthiness testing methods