Go to Post You must have a base on which to stand. Knowledge is the base that wisdom stands on. - Steve W [more]
Home
Go Back   Chief Delphi > FIRST > General Forum
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #16   Spotlight this post!  
Unread 03-01-2009, 17:32
brentwcc brentwcc is offline
Build Team/ Pit Crew
AKA: Brent von Massow
FRC #1503 (Spartonics)
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2006
Location: Niagara Falls, Ontario
Posts: 5
brentwcc is an unknown quantity at this point
Re: The Game Floor

From looking at the rules and the video we think its the "Glasliner FRP"
but the bumpy or "rippled" kind.
In 10.2.4.1 the rules say "The wheels supplied in the 2009 KOP are very different from previous years’ kit wheels. The tread material is Celcon M90, and has the following coefficients of friction on white, rippled fiberglass plastic sheet" then states the coefficents.

haven't found a dealer forsure yet but there are places in the states that sell it. dont no about prices yet. any one no where to buy?
__________________
Brent
Reply With Quote
  #17   Spotlight this post!  
Unread 03-01-2009, 17:34
brentwcc brentwcc is offline
Build Team/ Pit Crew
AKA: Brent von Massow
FRC #1503 (Spartonics)
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2006
Location: Niagara Falls, Ontario
Posts: 5
brentwcc is an unknown quantity at this point
Re: The Game Floor

we know** its "Glasliner FRP".
__________________
Brent
Reply With Quote
  #18   Spotlight this post!  
Unread 03-01-2009, 17:35
Qbranch Qbranch is offline
wow college goes fast.
AKA: Alex
FRC #1024 (Kil-A-Bytes)
Team Role: Alumni
 
Join Date: Apr 2006
Rookie Year: 2006
Location: Indianapolis
Posts: 1,174
Qbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond reputeQbranch has a reputation beyond repute
Re: The Game Floor

The floor material is a thin laminate pretty much exactly like the one you find on the walls of communal showers or in the kitchen or bathroom of a taco bell, the slightly bumpy white plastic stuff on the walls.

We found this stuff at our local Lowes (nice when your building materials are 1/2 mile from your shop) for about $28 per 4x8' sheet if I remember correctly.

-q
__________________
Electrical Engineer Illini
1024 | Programmer '06, '07, '08 | Driver '08
Reply With Quote
  #19   Spotlight this post!  
Unread 03-01-2009, 17:35
Leav's Avatar
Leav Leav is offline
Spud Gun Division
AKA: Leav Oz-Ari
FRC #3316 (D-Bug)
Team Role: Mentor
 
Join Date: Dec 2004
Rookie Year: 2005
Location: Technion, Haifa, Israel
Posts: 774
Leav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond reputeLeav has a reputation beyond repute
Send a message via ICQ to Leav Send a message via AIM to Leav Send a message via MSN to Leav
Re: The Game Floor

Classic model for friction does not depend on surface area.

maximum friction force F is given by the equation:

F=u*N

where u is the coefficient of friction between the two objects and N is the normal force between them.

in our case the net force that the floor is applying to the robot (the normal force) is the weight of the robot.

so:
F=u*W in our case.

so as you can classic friction does not depend on surface area.

if you were to model each wheel individually you would get a lower normal force (roughly the weight of the robot divided by the number of wheels) on each wheel so that N=W/n (W=total weight, n=number of wheels.)

so the force from each wheel would be F'=u*W/N

and we have n wheels so we get a total force of: F=F'*n=n*u*w/n=u*W

magic!

classic theory of friction breaks down in a lot of cases (for example spikes on a carpet), but should be very close to the reality in this year's game.

-Leav
__________________
"We choose to build robots this season and do the other things; Not because they are easy, but because they are hard."
-Paraphrasing JFK

Participated in FIRST as a student: 2005-2006 (But still learning every season!)
Mentor: 2008 - ? (Team 2630 2008-2011, and Team 3316 since 2013)
Engineer: 2011 - ? (B.Sc. and M.Sc. in Mech. Eng. from the Technion IIT)
FIRST Volunteer - 2007 - ? (MC, FTA, FIRST Aid etc.)
Reply With Quote
  #20   Spotlight this post!  
Unread 03-01-2009, 17:49
KarlSTA KarlSTA is offline
Registered User
FRC #2574
 
Join Date: Feb 2008
Rookie Year: 2007
Location: St. Anthony, Minnesota
Posts: 19
KarlSTA is an unknown quantity at this point
Re: The Game Floor

Also....will adding a lot of weight really help you stop and move easier. I mean yes you will get more force from friction but what about F=ma. You will need more force to slow yourself down as well so having more weight wouldn't really do you as much good would it???
Reply With Quote
  #21   Spotlight this post!  
Unread 03-01-2009, 17:58
dmlawrence dmlawrence is offline
MIT '14
FRC #1751 (Warriors)
Team Role: Alumni
 
Join Date: Jan 2007
Rookie Year: 2006
Location: Long Island
Posts: 63
dmlawrence is an unknown quantity at this point
Re: The Game Floor

According to the classical model, your acceleration will not depend on the weight of the robot.

a = F/m = umg/m = ug.

However, extra mass will aid you in collisions.
Reply With Quote
  #22   Spotlight this post!  
Unread 03-01-2009, 18:04
dtengineering's Avatar
dtengineering dtengineering is offline
Teaching Teachers to Teach Tech
AKA: Jason Brett
no team (British Columbia FRC teams)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Vancouver, BC
Posts: 1,833
dtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond reputedtengineering has a reputation beyond repute
Re: The Game Floor

Quote:
Originally Posted by dmlawrence View Post
According to the classical model, your acceleration will not depend on the weight of the robot.

a = F/m = umg/m = ug.

However, extra mass will aid you in collisions.
Don't forget that extra mass will also help you drag the trailer around. I would suggest that if your robot comes in underweight you'll do well to ballast it up to 120 pounds so that the ratio of weight on the undriven (trailer) to driven (robot) wheels is minimized.

Jason
Reply With Quote
  #23   Spotlight this post!  
Unread 03-01-2009, 18:12
writchie writchie is offline
Engineering Mentor
AKA: Wally Ritchie
FRC #2152 (Team Daytona)
Team Role: Coach
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Daytona Beach, Florida
Posts: 148
writchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond repute
Re: The Game Floor

Quote:
Originally Posted by smartkid View Post
I have to ask this, the rules state that we can buy and use additional official 2009 first wheels. I suggested that making a bot with multiple wheels (12 wheeled beast) would give us an edge however someone said that it would just redistribute the weight.

What I'm asking is (to someone who knows more physics) will more wheels (more surface area) give any real increase in traction? If so (or not) how is this calculated?

Thanks,
-Cody
Under normal circumstances, the "surface area" is irrelvant to traction. Friction is proportional to the
normal force (that is the force perpendicular to the surface, usually the weight supported by the wheel.
You can calculate friction from the dimensionless coefficient of friction multiplied by the Normal force on the
wheel. Do remember that forces (including friction) are vectors.

As in past years, a driven wheel cannot impose greater torque than that which occurs just before the wheel
breaks traction. The ability of a drive train to supply more torque than this is not very useful, although
it looks like the there is an 18 inch carpet border which will yield quite different characteristics and some
serious pushing may still be possible around the edges.

The main difference this year is that with a coeeficient of friction of approximately 0.06 rather than the
typical 1.0 - 1.2 or so, the peak torques on the FRP will be about 1/6th of those of past years.

Having 4 driven wheels will increase your pushing force (and acceleration) because all wheels will be able
to push (before any of them start of to slip). As in past years, 6 wheel drives will still be useful because
with a raised center wheel, you will always have two wheels slightly off the floor (or with very low normal
force) and the effective wheelbase will then be about half that of a 4 wheel drive without the center wheels.
This may be quite important with the required wheels. Note that (assuming the supplied information is correct)
the transverse coefficient of friction of the wheel/FRP interface is more than twice that of the inline
coefficient. Do not assume that it will be easier to skid steer on this surface. It may actually be much
harder. You will have to do the physics and the math and it might be best to get some input from your engineering
mentors on this.

I think that some of the interesting challenges of this year's game comes from deciding which "rules of
thumb" to throw away and which ones to keep.
Reply With Quote
  #24   Spotlight this post!  
Unread 03-01-2009, 18:12
smartkid's Avatar
smartkid smartkid is offline
Boom!
AKA: Cody Smith
FRC #1902 (Exploding Bacon)
Team Role: Mentor
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Florida
Posts: 81
smartkid has a spectacular aura aboutsmartkid has a spectacular aura about
Re: The Game Floor

Our team is known for being overweight (lots of 8020 == heavy), I doubt hitting 120 lbs will be a problem

To writchie: Thanks! That makes alot of sense but I suppose it doesn't change anything. It looks like FIRST wants to make sure that this will be a slippery game with luck involved.
__________________

Last edited by smartkid : 03-01-2009 at 18:17.
Reply With Quote
  #25   Spotlight this post!  
Unread 03-01-2009, 18:14
Travis Hoffman's Avatar Unsung FIRST Hero
Travis Hoffman Travis Hoffman is offline
O-H
FRC #0048 (Delphi E.L.I.T.E.)
Team Role: Engineer
 
Join Date: Sep 2001
Rookie Year: 2001
Location: Warren, Ohio USA
Posts: 4,047
Travis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond reputeTravis Hoffman has a reputation beyond repute
Re: The Game Floor

Quote:
Originally Posted by dtengineering View Post
Don't forget that extra mass will also help you drag the trailer around. I would suggest that if your robot comes in underweight you'll do well to ballast it up to 120 pounds so that the ratio of weight on the undriven (trailer) to driven (robot) wheels is minimized.

Jason
Speaking of the trailer, does anyone have any feedback on how easy it is to whip the trailer transversely? If the bot strafes sideways, how willingly does the trailer follow?

Also, here's a site with some sample pricing - hopefully you can find it cheaper locally:

http://www.frpshop.com/liner-panels-c-3_4.html

Maybe we'll get blue and pretend it's a water game....
__________________

Travis Hoffman, Enginerd, FRC Team 48 Delphi E.L.I.T.E.
Encouraging Learning in Technology and Engineering - www.delphielite.com
NEOFRA - Northeast Ohio FIRST Robotics Alliance - www.neofra.com
NEOFRA / Delphi E.L.I.T.E. FLL Regional Partner

Last edited by Travis Hoffman : 03-01-2009 at 18:21.
Reply With Quote
  #26   Spotlight this post!  
Unread 03-01-2009, 18:18
maltz1881 maltz1881 is offline
Registered User
#1322
 
Join Date: Feb 2005
Location: Fenton, Michigan
Posts: 225
maltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant futuremaltz1881 has a brilliant future
Re: The Game Floor

We were told by another team that Home depot carries it for $13.00 a sheet. I hope this is true instead of that $28.00. It is really thin material used on bathroom walls so I don't see why it would be $28.00. We are planning on going tomorrow and buying 5 or 6 sheets.
Reply With Quote
  #27   Spotlight this post!  
Unread 03-01-2009, 18:26
Charlie_A Charlie_A is offline
Registered User
FRC #1721 (Tidal Force)
Team Role: Programmer
 
Join Date: Dec 2007
Rookie Year: 2002
Location: Concord, N.H.
Posts: 8
Charlie_A is an unknown quantity at this point
Re: The Game Floor

Can I have a definition of incline friction vs transverse friction, please. I thought I was paying attention pre-season, apperentally not.
Reply With Quote
  #28   Spotlight this post!  
Unread 03-01-2009, 18:31
DanDon's Avatar
DanDon DanDon is offline
ohhh MY god
AKA: Dan Hoizner
FRC #0375 (The Robotic Plague)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2004
Location: Staten Island, NY
Posts: 1,432
DanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond reputeDanDon has a reputation beyond repute
Send a message via ICQ to DanDon Send a message via AIM to DanDon Send a message via MSN to DanDon
Re: The Game Floor

Quote:
Originally Posted by Charlie_A View Post
Can I have a definition of incline friction vs transverse friction, please. I thought I was paying attention pre-season, apperentally not.
Inline friction is along the direction of the wheel's rotation (rolling friction), transverse friction is along the axis of rotation (sliding friction).
__________________
Reply With Quote
  #29   Spotlight this post!  
Unread 03-01-2009, 18:40
writchie writchie is offline
Engineering Mentor
AKA: Wally Ritchie
FRC #2152 (Team Daytona)
Team Role: Coach
 
Join Date: Dec 2007
Rookie Year: 2007
Location: Daytona Beach, Florida
Posts: 148
writchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond reputewritchie has a reputation beyond repute
Re: The Game Floor

Quote:
Originally Posted by smartkid View Post
Our team is known for being overweight (lots of 8020 == heavy), I doubt hitting 120 lbs will be a problem

To writchie: Thanks! That makes alot of sense but I suppose it doesn't change anything. It looks like FIRST wants to make sure that this will be a slippery game with luck involved.
Like the real world, luck is always an element. I suspect, however, that luck
will be more involved with miraculous "shots" in the last 20 seconds by human
players. Changing the physics of the game, IMHO, makes it more a matter of
engineering than luck. As always, expect to see some amazing bots.
Reply With Quote
  #30   Spotlight this post!  
Unread 03-01-2009, 21:54
Mike AA's Avatar
Mike AA Mike AA is offline
Programmer and Mentor
AKA: Mike Aalderink
FRC #3458 (Code Blue)
Team Role: Programmer
 
Join Date: Jan 2003
Rookie Year: 1999
Location: Holland, Mi
Posts: 698
Mike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to beholdMike AA is a splendid one to behold
Send a message via MSN to Mike AA
Re: The Game Floor

Quote:
Originally Posted by maltz1881 View Post
We were told by another team that Home depot carries it for $13.00 a sheet. I hope this is true instead of that $28.00. It is really thin material used on bathroom walls so I don't see why it would be $28.00. We are planning on going tomorrow and buying 5 or 6 sheets.
Chances are the one at H.D. is a thinner version with different surface which is why its less expensive.

Edit: The $28 4X8 panels are the .090 thickness, the $13 is most likely the .063 panels which are much thinner and more flexable.

-Mike AA

Last edited by Mike AA : 03-01-2009 at 22:04.
Reply With Quote
Reply


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
174 gets off the floor Tetraman Robot Showcase 9 25-02-2008 17:04
Are the goals bolted to the floor? Leav Rules/Strategy 1 11-01-2005 03:31
Robots Hanging from the Floor Todd Derbyshire Rules/Strategy 16 13-01-2004 14:10
Height of the box stack from the floor tenfour General Forum 4 07-01-2003 10:26
Conduit on the floor Kyle Fenton General Forum 2 06-01-2002 14:49


All times are GMT -5. The time now is 00:55.

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


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi