FFy

FxF

Fy

Fx

Up

per

Darb

y H

igh

Sch

oo

l In

ven

Team

Fin

alist

60

1 N

ort

h L

an

sd

ow

ne

Ave

nu

e

Dre

xe

l H

ill,

PA

19

026

Me

ca

nu

m W

he

el

Dri

ve

Me

ca

nu

m D

rive

Sys

tem

~ M

ulti D

ire

ctio

na

l D

rive

Syste

m

NO

T just

anoth

er

om

ni-

wheel.

A

LL

WH

EE

L D

RIV

E,

AL

L D

IRE

CT

ION

S,

AL

L T

HE

TIM

E.

Ste

erin

g is a

ccom

plis

he

d w

ith

ou

t p

ivo

tin

g a

ny w

he

el.

Ab

ility

to

sp

in a

bou

t in

it’s o

wn

fo

ot p

rin

t.

Ab

ility

to

Dri

ve

Sid

ew

ays

! D

rive

in

an

y d

ire

ctio

n o

r co

mb

ina

tion

of

dire

ctio

ns.

Un

ma

tch

ed

ma

ne

uve

rab

ility

. In

dep

end

en

t m

oto

r con

tro

ls t

o e

ach

wh

ee

l.

Dis

cre

te,

dire

ction

al con

tro

l th

ru a

sin

gle

jo

ystick in

terf

ace

. E

ffic

ien

t d

rive

tra

in m

axim

ize

s b

att

ery

life.

Ro

bu

st

relia

ble

con

str

uctio

n.

Typic

al

Sin

gle

-Hub

Sp

lit-R

olle

r

Mecan

um

Whe

el

Ve

cto

r A

na

lys

is o

f th

e

Me

ca

nu

m D

riv

e S

ys

tem

FFy

Fx

Ho

w T

he

Me

ca

nu

m

Wh

eel

Dri

ve S

yste

m

Wo

rks

The M

ecanum

wheel drive s

yste

m.

Ste

ering in a

Me-

canum

dri

ve s

yste

m is a

ccom

plished b

y v

ary

ing t

he

speed a

nd r

ota

tion o

f each w

heel in

dependently.

The

wheels

exert

a b

iased forc

e t

o t

he g

round d

ue t

o t

he

45° inclination o

f th

e r

oller

to t

he d

riven h

ub a

xle

.

The w

heels

are

arr

anged in o

pposin

g p

airs form

ing a

dia

mond p

att

ern

on t

he f

loor.

W

heel ro

tation induces a

dia

go-

nal fo

rce p

erp

endic

ula

r to

the r

oller

axis

. T

his

forc

e is b

roken d

ow

n into

Fx

and Fy c

om

ponents

. B

ecause t

he

wheels

are

arr

anged in o

pposin

g p

airs

adja

cent

wheels

can a

nd d

o c

ancel equal and o

pposite

forc

es.

See fig

ure

1,

the a

ction is t

o d

rive forw

ard

. A

ll

wheels

rota

te in t

he s

am

e d

irection.

The Fx forc

es

are

equalized a

nd c

ancel each o

ther

out.

The r

esul-

tant

motion is t

he u

n-

resolv

ed Fy forc

es a

nd

there

fore

forw

ard

mo-

tion.

In

fig

ure

2,

the

desired m

otion is a

sid

ew

ays m

ove.

The

adja

cent

wheels

on

each s

ide a

re d

riven in

opposite d

irections.

The Fy forc

es a

re

equalized a

nd c

an-

Fig

ure

1

cele

d.

The r

esultant

motion is a

late

ral or

sid

ew

ays t

ravel.

Spin

motions a

re

sim

ilar

to a

conven-

tional ta

nk s

teer

ro-

bot.

O

n o

ne s

ide

both

moto

rs a

re

driven forw

ard

while

oth

er

sid

es a

re d

riven

the o

pposite d

irec-

tion.

The a

dja

cent

wheels

cancel th

e Fx v

ecto

r com

ponents

and s

pin

is

accom

plished.

Oth

er

com

bin

ations o

f

these m

otions r

esult in

spin

s,

arc

s,

and a

ngula

r

movem

ents

.

Fig

ure

2

Sim

plifi

ed V

ecto

r Diagr

amm

ing

Dra

w the

prim

ary

forc

e ve

ctor

s

Take

eac

h of

the

for

ce v

ecto

rs a

nd

ADD the

m tog

ethe

r Hea

d to

Tail

Dra

w a

res

ulta

nt v

ecto

r to

illu

stra

te

the

dire

ction

and

mag

nitu

de o

f th

e re

sulta

nt F

ORCES.