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June 12, 2001Jeong-Su Han

An Autonomous Vehiclefor People with Motor

Disailitiesby G. Bourhis, O.Horn, O.Habert and A. Pruski

Paper !e"iew

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$%ecti"es

()o provide an aid to *obi+ity for disab+ed peop+e #ho di-cu+t of i*possib+e to drive a conventiona+ #hee+chai(ot to *ake the robot as autono*ous as possib+e but t

fu++ advanta/e of the user0s abi+ities#ithout burdenin/#ith too *uch #ork+oad.

$%ecti"es

respirator VoiceJo&stic'

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VAHM !oot

irst prototype of the VAH robot

(be/an in 13(!obuter *obi+e base(A #hee+chair seat(P4 $35 co*puter(a be+t of u+trasonic sensors(*an(*achine interface 6/raphic screen7

4urrent prototype of the VAH robot

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#ontrol mo(e

(the *achine is on+y used to trans*it and adapt data fr the user and the *obi+ity task.

Manual Mo(e

(the *achine has co*p+ete contro+ of the syste*,once a /oa+ is se+ected.

Automatic Mo(e

(contro+ is divided bet#een the user and the *achine.(sharin/ de/rees of +iberty.

e./.7 the user8 choose #ay to /o, the *achine8 obstac+e avoidance

Semiautonomous Mo(e

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Software

Architecture

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Perception control

(?oca+i=ation(%tatic +oca+i=ation vs. 'yna*ic +oca+i=ation

(ree space detection(!e+ative+y +ar/e area 6 a radius of 2 * around the robot7 #i+

considered as an obstac+e in free space detection.

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(based on the #hee+chair0s behavior.(Behavior is dened by the orientation of a strai/ht +ine /oin/ thro the fra*e0s ori/in.()he direction is eDua+ to the avera/e of the behaviors #ei/hte

by *easured va+ue0s inverse.

a"igation control

$stacle a"oi(ance

=

=

=m

i

m

i

d

idist

idist

i

1

1

)(

1

)(

)(

8 the nu*ber of sensors8 the robot0s behavior associated to sensor i8 the distance *easured by sensor i8 the an/+e of the strai/ht +ine

m)(i

d

)(idist

()he re+ative+y +ar/e area 6a radius of 2 * around the robot7 #i++ b considered as an obstac+e.

ree space search

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()he user te++s the robot #hich direction to proceed in usin/ a desi syste* or a joystick.()he #hee+chair #i++ *ove a+on/ this direction.

a"igation control

Direction following

(ollowing the straight line parallel to a wall.()he eDuation of the strai/ht +ineis co*puted fro* the data sent b the three u+trasonic sensors+ocated on the side of the #hee+chairthe #a++ that is to be fo++o#ed.

(:f the #a++ is too c+ose or is not strai/ht, ostacle a"oi(ance alg

is used.

/all following

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()he environ*enta+ *ode+ is fed into the *achine prior to any p+a(2(' space, 2&5 by 2&5 ce++s.

1. )he si=e and position of the obstac+es have been introduced usi

a /raphic editor, the environ*enta+ *ode+ is obtained.2. )he current position point and the /oa+ to reach are kno#n, path p+annin/ for a punctua+ robot in an area coverin/ the 1.& ti #idth of the #hee+chair is co*puted.". )he trajectory is turned into a seDuence of arcs or circ+es to tak

account the fact that the *obi+e isnonho+ono*ic.

$. )he robot *oves in accordance #ith thenavi/ation a+/orith*.

( not opti*a+ so+ution,processin/ ti*e is under 1s.

a"igation control

Path planning

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#ommunication

control (an(*achine interface is essentia+ toensure the e-ciency of technica+ aids.(A #ide ran/e of sensors is used

for po#ered #hee+chair.(hand( and chin(contro++ed joysticks,

*echanica+ s#itches, breath sensors, speech reco/nition. s#itches or ana+o/ sensors.

(a single-switch case8 an icon or an ar of the screen is used for scannin/ over severa+ possib+e choices, then va+idatin

(analog sensors case8 the disab+ed pe can contro+ a proportiona+ sensor by *ovin/ a virtua+ joystick disp+ayed o the screen.

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Discussion

()he second prototype of the VAH robot as described.()he choice of the auto*ation +eve+ usua++y depends on para*eters that are easi+y apprehended8

( sin/+e(s#itch or proportiona+ *an(*achine interface( *ode+ed or non(*ode+ed environ*ent.

( this contro+ se+ection is current+y +eft up to the user.

()he user is +eft #ith on+y t#o contro+s8( choosin/ the direction.

( stoppin/ the #hee+chair.

Discussion