Calculation of Torque and RPM

If you are comfortable with basic mathematics and wish to know the torque and rpm you require for your motor then this section is for you [or you can calculate it from the ‘motor calculator’ which will be uploaded soon]

Calculation of torque:

Let’s calculate the torque you require for your bOt to move. Consider the example given below of a bOt for understanding.

  • No of wheels = 3 with differential drive
  • No of motors = 2

The bOt is front wheel driven and has a rear castor wheel.

  • Coefficient of friction = 0.6 and radius of wheel = 3cm
  • Weight of bot (W=mg= 20N) (f= friction, N= normal)

Kinematic Modelling

When the bOt is accelerating in the forward direction, the friction acts in the forward direction on the front wheels (the friction is the force that drives the bot, just like you can’t move without friction) and on the rear castor wheel the friction acts in opposite direction (see figure above). Assuming that we have an impending motion i.e. the torque is just sufficient to start the bOt. Following are the equations of motion:-

N1+ 2*N2= W

f2x* r – τ= 0

Since there is an impending motion hence f2x= µN.

For a motor the impending torque should be able to overcome the static friction torque. After this, the torque required for rotating the wheels of bOt reduces and the rpm of motor will increase, hence the speed of bOt.

N= W/3 (considering that weight is equally distributed)

µ*W/3*r- τ=0

0.6*(20/3)*0.03- τ=0

τ= 0.12N-m or 1.2kg-cm

It has been assumed that the tyres can provide maximum grip or the traction force. To understand this concept consider the following example. Suppose your car is moving on mud, it will be very difficult for you to control the car due to slippage due to insufficient grip. From kinematic analysis it is seen that the maximum traction force is equal to the frictional force.

It is advisable to buy a 'high torque' motor as it can carry more load, move on higher slope and also if you have a rough track (that has wet mud, gravels, etc). Although this is a simplified model yet approximate values of torque (close to actual values) can be calculated.

Calculating the rpm of motor:

What should be want the maximum speed of your bOt to be? Do you know beyond a certain speed you won’t be able to control your bOt. Let’s calculate this speed.

Consider an example of an arena where the track is designed as shown in the above figure. Suppose the maximum speed of your bOt is 0.5 m/s and it transverses through the straight track of length 2 metre, the time taken is approximately around 4-6 seconds. It is believed that this is an optimum speed for the bOt.

Speed of bot= rpm of motor* radius (while moving forward)

0.5(m/s) = ω * 0.03(m)

ω= 17 (rad/s) = 17 * 60 /2π (rpm) = 160 (rpm)

Still rpm upto 300 is comfortable or rather controllable. If you feel that the rpm of your bOt is difficult to handle then you should choose a lower voltage rating.

Speed of bOt = (speed of left wheel + speed of right wheel)/2

When moving forward: -

speed of left wheel = speed of right wheel

Now while taking the turn of radius 20cm (see figure above) you will obviously switch off one motor.

Here the speed of right wheel = 0m/s

Therefore, speed of bOt = speed of left wheel

=> speed of bOt = 0.5(m/s)/2

This means that you will approximately take 1.2s to take the turn. You can do a similar analysis of your own bOt with different specifications.

Tags:

Comments

Member since:
7 August 2017
Last activity:
10 weeks 14 hours

kanye west shoes


michael kors bags


ua shoes


ray ban erika


prada handbags


payless shoes online


official kate spade website


coach outlet online


pandora rings


pandoracharms


pandora rings uk


Coach Sunglasses Outlet


balenciaga outlet


Engagement Rings - Official


Nike Air Max 180


official michael kors


Ray Ban sunglasses


shoes sale


Nike Air Max


Air Max 180


burberry outlet


Dreamland Jewelry - Official


birkenstock sandals


birkenstock


Nike Air Max Couple


coach outlet online


prada outlet online


louis vuitton outlet online


Nike Air Jordan


gel kayano


official michael kors


michael kors outlet bags


Hugo Boss Store


payless shoes


Premier Jewelry - Official


ray ban outlet


Coach Handbags


pandora sale


coach watches


nike store


football jerseys


louis vuitton outlet online


coach outlet online sale


Add Your Link Free


backlink


louis vuitton us


michael kors


Nike Air Jordan Enfants


michael kors


Michael Kors Handbags Outlet Sale


kate spade outlet online


Green Cleaned


ugg boots


sunglasses


Nike Blazer Femmes


evbid


Wine


coach outlet


birkenstock outlet


Burberry Australia


payless near me


Chanel Outlet


north face sale


Nike Air Max


Prada Shoes - Official


michael kors outlet


ray ban wayfarer sunglasses


Oakley Sunglasses


puma sneakers outlet


payless shoes


nike free shoes


diesel watches


burberry outlet canada


prada sale


puma sneakers sale


louis vuitton outlet


Air Max 180 Homme


Jewelry Armoire - Official


coach handbags sale


Hermes Outlet


timberland shoes


Nike Air Max 2017


coachs outlet


louis vuitton outlet online


Nike Jordans


football jerseys


burberry outlet sale


Nike Free 3.0


michael kors outlet online


ray ban wayfarer


ray ban sunglasses


Rolex Watch


michael kors


michael kors


nike huarache shoes


ray ban sale


Adamson


pandora necklaces


kate spade italy


coach australia


pandora uk


pandora uk


swatch watch


michael kors watches


michael kors


rayban prescription sunglasses


Brighton Jewelry - Official


prada outlet online


Nike Air Force


michael kors outlet


fulam shoes


softball jerseys


Nike Air Max


balenciaga us


Air Max 1 Homme


michael kors


Watches


Air Jordan Enfant


chrome store canada


sunglasses store


coach outlet


michael kors outlet


Nike Free Run


mk outlet online


michael kors outlet


the beat


seiko watches


michael kors


Lifestyle


Air Max 90 Femme


hermes outlet


Nike Air Jordan enfants


hermes outlet


prada purses


kate spade outlet


nike jordan shoes


me adc8.7

Member since:
7 July 2017
Last activity:
6 weeks 20 hours

2017.7.7yangping

coach outlet

moncler

mbt shoes

cheap jerseys from china

christian louboutin shoes

coach outlet online

kate spade

michael kors outlet clearance

nike free run flyknit

marc jacobs bags

fit flops

coach factory outlet

kate spade handbags

kd 9 shoes

cheap oakley sunglasses

nike air max 90

chi flat iron

kate spade outlet

longchamp handbags

hermes bags

ralph lauren outlet

coach outlet

salomon shoes

burberry outlet store

coach outlet online

christian louboutin sale

michael kors outlet

polo outlet

coach outlet online

nike free flyknit

air max

nike store

louboutin uk

houston texans jerseys

coach outlet

coach factory outlet

coach factory outlet

louis vuitton outlet

air jordan retro

levis jeans

polo ralph lauren outlet online

oakley sunglasses

moncler outlet

mont blanc

adidas nmd

true religion outlet

fit flops

steph curry shoes

cheap jordans

ralph lauren pas cher

michael kors outlet clearance

fitflops sale clearance

cheap nike shoes

coach outlet store

pandora charms sale

coach outlet

mont blanc pens

cheap mlb jerseys

coach factory outlet

ralph lauren outlet online

michael kors outlet online

birkenstock pas cher

coach factory outlet online

cheap nfl jerseys wholesale

polo ralph lauren outlet online

toms shoes outlet

pandora charms sale clearance

air jordans

ed hardy

ed hardy clothing

pandora charms

mont blanc pens

adidas superstar

mulberry purse

nike shoes for men

nike air max outlet

nike store

true religion

hermes handbags

celine outlet

cheap ray ban sunglasses

oakley sunglasses

ralph lauren sale clearance

adidas yeezy

borse gucci

louis vuitton handbags outlet

fitflops

michael kors bags

true religion jeans

louis vuitton outlet

oakley sunglasses

christian louboutin sale

christian louboutin

doudoune moncler

michael kors outlet

michael kors outlet clearance

versace shoes

louis vuitton outlet online

coach outlet

mulberry handbags

columbia shoes

pandora jewelry outlet

red bottoms shoes

ralph lauren

yeezy boost 350

pandora outlet

birkenstock sandals

christian louboutin

coach outlet

nike air max

parker pens

longchamp bags

vans shoes

yeezy boost

ralph lauren sale clearance

birkenstocks

nike roshe run

hollister clothing store

adidas pas cher

dansko sandals

discount oakley sunglasses

oakley sunglasses

hermes handbags

adidas yeezy

adidas yeezy

polo ralph lauren

james harden shoes

ralph lauren uk

hermes birkin

pandora

coach outlet

mlb jerseys cheap

true religion outlet

longchamp uk

coach outlet store online clearances

fendi handbags

rolex replica

sac longchamp pas cher

michael kors outlet

coach outlet

dansko shoes

dansko outlet store

gucci outlet

nike air max

christian louboutin outlet

wholesale nike shoes

adidas shoes

coach bags

jordan shoes

kate spade outlet

sac longchamp

nike outlet

coach factory outlet

coach factory outlet

tory burch outlet

ray ban sunglasses

birkenstock shoes

ralph lauren uk

vans outlet store

nike shoes

oakley sunglasses

adidas nmd

ralph lauren outlet

coach outlet

michael kors outlet clearance

adidas yeezy

tory burch outlet

michael kors uk

birkenstock sandals

cheap jordans

birkenstocks

clarks outlet

christian louboutin outlet

salomon shoes outlet

rolex replica watches

new england patriots jerseys

ray ban sunglasses discount

ralph lauren uk

fred perry polo

yeezy boost 350 v2

cheap mont blanc

rolex watches

swarovski crystal

true religion jeans

sac michael kors

fitflops

birkenstock shoes

ralph lauren sale clearance

cheap nfl jerseys

coach outlet

jimmy choo

mbt shoes

michael kors handbags

michael kors outlet

coach factory outlet

coach factory outlet

oakley sunglasses outlet

adidas yeezy

ralph lauren outlet

sac longchamp pas cher

coach outlet

adidas shoes

adidas shoes

ralph lauren outlet

michael kors handbags

oakley sunglasses outlet

louboutin pas cher

pandora jewelry

hermes outlet

hermes handbags

polo ralph lauren outlet

gucci outlet

pandora outlet

coach outlet

fitflops

clarks outlet

coach outlet

michael kors

cheap jerseys

kevin durant shoes

valentino shoes outlet

kate spade outlet store

tods outlet

birkenstock sandals

nike shoes

burberry outlet canada

cheap jordan shoes

coach factory outlet

red bottoms

michael kors outlet online

jordan shoes

louboutin

toms shoes

adidas uk

golden state warriors jerseys

cheap jordans

mulberry outlet

pandora bijoux

adidas superstar

michael kors outlet

cheap oakley sunglasses

coach factory outlet

ralph lauren uk

ed hardy

pandora jewelry

pandora uk

coach outlet

coach factory outlet

fendi handbags

tory burch outlet store

adidas superstar shoes

adidas nmd

pandora bracelet

dolce and gabbana outlet

yeezy boost 350

longchamp handbags

yeezy boost

coach factory outlet

cheap nike air max

adidas outlet

ralph lauren

nike outlet online

adidas superstar

polo ralph lauren

polo ralph lauren

louboutin chaussures

coach outlet store

supra shoes

polo ralph lauren

adidas yeezy boost 350

nike free 5.0

giuseppe zanotti outlet

pandora charms

fake rolex

louis vuitton outlet store

michael kors handbags

air jordan uk

polo outlet

nike shoes outlet

michael kors canada

coach factory outlet

pandora jewelry

pandora charms uk

oakley sunglasses

coach outlet

adidas shoes

yeezy boost

cat shoes

dallas cowboys jerseys

clarks shoes

fred perry

sac longchamp pliage

nike outlet store

toms outlet

christian louboutin outlet

nike outlet

coach outlet

air max 95

nmd adidas

swarovski jewellery

jordans

mbt shoes

fitflops sale clearance

ralph lauren outlet

kate spade handbags

fitflops

michael kors canada

cheap jordans

nike air max

official coach factory outlet

longchamp bags

toms shoes outlet

moncler jackets

michael kors outlet

marc jacobs handbags

birkenstock sandals

nmd adidas

burberry sale

coach handbags

adidas shoes

pandora uk

mlb jerseys wholesale

michael kors outlet

ecco shoes

pandora jewelry

coach outlet

moncler outlet

michael kors handbags

celine outlet store

pandora jewelry

swarovski crystal

ultra boost

true religion jeans

coach factory outlet online

nmd shoes

nmd adidas

birkenstock outlet

polo ralph lauren

seattles eahawks jerseys

polo ralph lauren

coach outlet

mont blanc

cheap jordans

louboutin shoes

kate spade handbags

coach outlet store

cheap mlb jerseys

ray ban sunglasses

coach outlet store

oakley sunglasses

polo ralph lauren outlet online

adidas uk

longchamp uk

adidas outlet

fitflops shoes

nike air max 90

air max 2017

cheap ray bans

coach factory outlet

mulberry bags

salomon shoes

longchamp outlet store

cheap jordans

cheap mlb jerseys

nike air max

under armour shoes

valentino shoes

adidas shoes

ray ban sunglasses

coach outlet

nike outlet

michael kors outlet

hollister co

discount ray ban sunglasses

nike factory store

red bottoms

adidas yeezy boost

louis vuitton handbags

christian louboutin

rolex replica watches

michael kors uk

kate spade outlet

fitflops uk

burberry outlet

true religion outlet

pandora soldes

christian louboutin shoes

yeezy boost 350

louis vuitton outlet

parada handbags

burberry outlet

columbia outlet online

coach factory outlet

coach outlet store online

michael kors outlet

coach outlet

cveland cavaliers jerseys

polo ralph lauren outlet

yeezy 350 boost

louis vuitton outlet

pandora charms

ray ban sunglasses

christian louboutin

miami heat jerseys

ralph lauren sale clearance

fred perry

kate spade outlet

adidas shoes

rolex watches

adidas nmd

nike roshe

coach outlet

birkenstock sandals

valentino

rayban

dansko outlet

christian louboutin outlet

cheap nfl jerseys

clarks shoes

timberland boots

ralph lauren outlet

pandora charms

nike air max 90

replica watches

ralph lauren outlet online

cheap jordans

mulberry handbags

adidas trainers

red bottoms shoes

longchamp outlet

pandora outlet

pandora charms

ralph lauren clearance

oakley sunglasses

yeezy boost 350

cheap jordans free shipping

longchamp outlet

adidas superstar

michael kors outlet online

michael kors outlet clearance

michael kors handbags

burberry outlet online

mulberry uk

michael kors outlet

pandora charms

moncler jackets

kate spade handbags

michael kors outlet

toms shoes

michael kors uk

tods shoes

ysl handbags

coach outlet store

michael kors

coach outlet store

coach canada

giuseppe zanotti sneakers

coach outlet

nike air max pas cher

nike air max

adidas outlet

nike free run black

longchamp uk

denver broncos jerseys

cheap oakley sunglasses

michael kors handbags

adidas nmd

adidas outlet

pandora jewelry

yeezy boost

prada outlet

longchamp handbags

fitflops

fitflop sandals

coach outlet store

yeezy boost 350

nike store