OCCRA
Go to Post The GDC made something easier??? Link or it didn't happen! - JesseK [more]
Home
Go Back   Chief Delphi > Technical > Robotics Education and Curriculum
CD-Events   CD-Media   CD-Spy   FRC-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 01-17-2010, 10:45 PM
caincteam2777 caincteam2777 is offline
Registered User
FRC #2777
 
Join Date: Jan 2010
Location: blackwell
Posts: 30
caincteam2777 has a spectacular aura aboutcaincteam2777 has a spectacular aura about
Calculating of traction/friction

is there a formula that can calculate the amount of traction/friction your robot has with a set number of wheels
  #2   Spotlight this post!  
Unread 01-17-2010, 10:48 PM
mathman05 mathman05 is offline
Registered User
None #1308
 
Join Date: Jan 2010
Location: Cleveland, OH
Posts: 10
mathman05 is an unknown quantity at this point
Re: Calculating of traction/friction

The number of wheels (the amount of surface area you have on the field) does not effect the amount of friction that you will have. It's a physics thing.

Different types of wheels will have different coefficients of friction on the playing field, though.
  #3   Spotlight this post!  
Unread 01-18-2010, 12:06 AM
caincteam2777 caincteam2777 is offline
Registered User
FRC #2777
 
Join Date: Jan 2010
Location: blackwell
Posts: 30
caincteam2777 has a spectacular aura aboutcaincteam2777 has a spectacular aura about
Re: Calculating of traction/friction

well the wheels have 1.3 coefficient of friction
  #4   Spotlight this post!  
Unread 01-18-2010, 12:20 AM
Vikesrock's Avatar
Vikesrock Vikesrock is offline
Team 2175 Founder
AKA: Kevin O'Connor
no team
Team Role: Engineer
 
Join Date: Mar 2006
Rookie Year: 2007
Location: Manchester, NH
Posts: 3,305
Vikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond repute
Send a message via AIM to Vikesrock Send a message via MSN to Vikesrock Send a message via Yahoo to Vikesrock
Re: Calculating of traction/friction

Force of Friction = Coefficient of Friction * Normal Force
Normal force = Mass * Acceleration due to gravity

If all of your wheels touching the ground have the same coefficient of friction the calculation can be performed once using the entire mass of your robot to find the normal force.

If some of your wheels have a different coefficient of friction the calculation becomes more difficult as the location of your center of gravity will determine how much normal force is applied by each wheel.
__________________


2007 Wisconsin Regional Highest Rookie Seed & Regional Finalists (Thanks 930 & 2039)
2008 MN Regional Semifinalists (Thanks 2472 & 1756)
2009 Northstar Regional Semifinalists (Thanks 171 & 525)
  #5   Spotlight this post!  
Unread 01-18-2010, 12:29 AM
caincteam2777 caincteam2777 is offline
Registered User
FRC #2777
 
Join Date: Jan 2010
Location: blackwell
Posts: 30
caincteam2777 has a spectacular aura aboutcaincteam2777 has a spectacular aura about
Re: Calculating of traction/friction

each has 1.3

formula?
  #6   Spotlight this post!  
Unread 01-18-2010, 12:33 AM
Vikesrock's Avatar
Vikesrock Vikesrock is offline
Team 2175 Founder
AKA: Kevin O'Connor
no team
Team Role: Engineer
 
Join Date: Mar 2006
Rookie Year: 2007
Location: Manchester, NH
Posts: 3,305
Vikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond reputeVikesrock has a reputation beyond repute
Send a message via AIM to Vikesrock Send a message via MSN to Vikesrock Send a message via Yahoo to Vikesrock
Re: Calculating of traction/friction

I just posted it.

Find the normal force by taking the mass of your robot and multiplying by the acceleration due to gravity (F=mA). Then multiply this number by the coefficient of friction to find the force of friction.

You should be able to find the conversion between lbs (weight) and (kg) for Earth and the acceleration due to gravity on Earth in m/s fairly easily. Those are the only things you need to perform the calculation.
__________________


2007 Wisconsin Regional Highest Rookie Seed & Regional Finalists (Thanks 930 & 2039)
2008 MN Regional Semifinalists (Thanks 2472 & 1756)
2009 Northstar Regional Semifinalists (Thanks 171 & 525)
  #7   Spotlight this post!  
Unread 01-18-2010, 12:37 AM
ubermeister's Avatar
ubermeister ubermeister is offline
Registered User
AKA: Eric VA
FRC #0449 (The Blair Robot Project)
Team Role: Leadership
 
Join Date: Jan 2008
Rookie Year: 2007
Location: Silver Spring
Posts: 48
ubermeister is a jewel in the roughubermeister is a jewel in the roughubermeister is a jewel in the roughubermeister is a jewel in the rough
Re: Calculating of traction/friction

The formula for force of friction is sum(mu*F_n), where mu is the coefficient of friction for each wheel (i hear 1.3 for the FIRST sticky wheels) and F_n is the normal force (weight) on each wheel. Surface area (i.e. number of wheels) does not come into play. If all your wheels are identical, mu=1.3, and your robot weighs 150 lbs, the force of friction is 195 lbs. This means you can accelerate at up to 195 pounds force / 150 pounds mass = 41 ft/sec^2 before your wheels start to slip.
__________________


  #8   Spotlight this post!  
Unread 01-20-2010, 06:59 PM
jmanela's Avatar
jmanela jmanela is offline
+1 is BIGGER than -1
AKA: Joshua Manela
FRC #2586 (Fondy Fire)
Team Role: College Student
 
Join Date: Aug 2008
Rookie Year: 2009
Location: Michigan
Posts: 314
jmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to behold
Re: Calculating of traction/friction

The coeficient of friction for the KOP wheels are located in section 10 of the game manual. 10.2.4.

Quote:
10.2.4 The Drive Train
Wheels - The wheels supplied in the 2010 KOP are a combination of slick and sticky treads. The slick
tread material is Celcon M90, and has the following coefficients of friction on white, rippled fiberglass
plastic sheet
Inline, static: 0.06
Inline, dynamic: 0.05
Transverse, static: 0.14
Transverse, dynamic: 0.10
__________________
||2009|| Entrepeneurship Award, QF - Traverse City | Rookie All Star, QF - Detroit | Highest Rookie Seed, Rookie All Star, QF - Michigan State Championship | Finalist - MARC ||2010|| Engineering Inspiration, Website Award, SF- Kettering | Judges Award, Website Award, SF - Detroit | Website Award, Winner, Michigan State Champ //Thank you 469 and 1918!! | Finalist - MARC ||2011|| Engineering Inspiration, Website - Kettering | Entrepreneurship, Website, Finalist - Waterford | Website - MSC

Last edited by jmanela : 01-20-2010 at 07:03 PM.
  #9   Spotlight this post!  
Unread 01-20-2010, 08:35 PM
kramarczyk's Avatar
kramarczyk kramarczyk is offline
is getting his kicks.
AKA: Mark Kramarczyk
FRC #3096 (Highlanders)
Team Role: Mentor
 
Join Date: Mar 2006
Rookie Year: 2006
Location: Sterling Heights, MI
Posts: 602
kramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond reputekramarczyk has a reputation beyond repute
Re: Calculating of traction/friction

The numbers in the manual are bogus since we are playing on carpet instead of
Quote:
white, rippled fiberglass plastic sheet
Additionally, we have two different wheels in the kit and that is only a spec for one... which coincidentally is the exact data from last year.

From the AndyMark site I find that the sticky wheels are listed at 1.0 and the slick wheels at 0.2.

I'd go with those numbers. Expect this to be covered in a future update.
__________________
Mark

Brick walls are for other people. - Randy Pausch
  #10   Spotlight this post!  
Unread 01-21-2010, 09:33 PM
jmanela's Avatar
jmanela jmanela is offline
+1 is BIGGER than -1
AKA: Joshua Manela
FRC #2586 (Fondy Fire)
Team Role: College Student
 
Join Date: Aug 2008
Rookie Year: 2009
Location: Michigan
Posts: 314
jmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to beholdjmanela is a splendid one to behold
Re: Calculating of traction/friction

thanks, i didn't see that.
__________________
||2009|| Entrepeneurship Award, QF - Traverse City | Rookie All Star, QF - Detroit | Highest Rookie Seed, Rookie All Star, QF - Michigan State Championship | Finalist - MARC ||2010|| Engineering Inspiration, Website Award, SF- Kettering | Judges Award, Website Award, SF - Detroit | Website Award, Winner, Michigan State Champ //Thank you 469 and 1918!! | Finalist - MARC ||2011|| Engineering Inspiration, Website - Kettering | Entrepreneurship, Website, Finalist - Waterford | Website - MSC
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Calculating relays. VEN Electrical 3 04-24-2007 10:23 PM
calculating distance sur2124 Programming 10 03-15-2006 06:36 PM
Calculating Wheel Size phrontist Technical Discussion 15 09-07-2004 06:55 PM
Friction, traction, torque - oh my... Gui Cavalcanti Technical Discussion 30 08-13-2002 06:01 PM


All times are GMT -5. The time now is 06:47 PM.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi