Best Wheel Grip?

[archiver]

Posted by Eric Reed at 1/9/2001 11:07 PM EST


Coach on team #481, NASA Ames / De Anza High School, from De Anza High School and It could be you!.



We are looking for ideas to modify the wheelchair wheels or create new wheels. We want the most grip possible. Any suggestions?

Thanks,

Eric.

[archiver]

Posted by Ryan at 1/9/2001 11:42 PM EST


Student on team #30, Fury, from High Technology High School and CelWave.


In Reply to: Best Wheel Grip?
Posted by Eric Reed on 1/9/2001 11:07 PM EST:



: We are looking for ideas to modify the wheelchair wheels or create new wheels. We want the most grip possible. Any suggestions?

: Thanks,

: Eric.

Last year at the nationals we really weren't getting a good grip either. We got desperate and used a soldering iron to engrave divots spaced evenly along the wheels. We wer surprised because this gretaly enhanced the traction.
-Rc

[archiver]

Posted by Ken Leung at 1/9/2001 11:42 PM EST


Student on team #192, Gunn Robotics Team, from Henry M. Gunn Senior High School.


In Reply to: Best Wheel Grip?
Posted by Eric Reed on 1/9/2001 11:07 PM EST:



One possible method is to find good belt material with great traction and wrap it around, lathe the wheel flat so the belt will fit on it well, and use a combination of screws and glue to secure it on the wheel.

[archiver]

Posted by Bill Beatty at 1/10/2001 10:22 AM EST


Other on team #71, Team Hammond, from Team Hammond.


In Reply to: Belt material
Posted by Ken Leung on 1/9/2001 11:42 PM EST:



If I am reading the rules right, using a belt material on the wheels this year is a violation unless the material comes from Small Parts or a timming belt from the additional material list. Or am I missing something?

[archiver]

Posted by Nate Smith at 1/11/2001 12:42 PM EST


Other on team #66, GM Powertrain/Willow Run HS, from Eastern Michigan University and GM Powertrain.


In Reply to: Belt Material A NO-NO?
Posted by Bill Beatty on 1/10/2001 10:22 AM EST:



: If I am reading the rules right, using a belt material on the wheels this year is a violation unless the material comes from Small Parts or a timming belt from the additional material list. Or am I missing something?

Based on Q/A17, I'd have to say that you're right...unless it's a belt you can get from SPI, you're limited to 20 ft of timing belt...of course, as I heard Eric say at the end of kickoff while talking to somebody, there's no limit on how WIDE that timing belt can be...who knows what people will be able to find? =)

Nate

[archiver]

Posted by Raul at 1/11/2001 1:28 PM EST


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.


In Reply to: Belt Material A NO-NO?
Posted by Bill Beatty on 1/10/2001 10:22 AM EST:



So, does anyone know a source for a sticky timing belt?

Raul

: If I am reading the rules right, using a belt material on the wheels this year is a violation unless the material comes from Small Parts or a timming belt from the additional material list. Or am I missing something?

[archiver]

Posted by Andy Baker at 1/11/2001 2:33 PM EST


Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.


In Reply to: Source for Sticky Timing Belt?
Posted by Raul on 1/11/2001 1:28 PM EST:



My "belts" folder has these options:

1. Optibelt makes polyurethane belts... they call their optibelt-ZRM a "supergrip" model: 630-628-8400

2. Mectrol makes urethane belts... check out www.mectrol.com.

3. Fenner Drives (of Fenner Manheim) makes belts... but they may be more into the custom area... www.fennerdrives.com

4. Voss makes belts, but they are mostly custom... 847-673-8900.

Your bud,
Andy B.

[archiver]

Posted by Raul at 1/11/2001 3:50 PM EST


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.


In Reply to: "Sticky" belt vendors
Posted by Andy Baker on 1/11/2001 2:33 PM EST:



Thanks Andy.

Are these timing belts or just regular belts? The rules say they must be timing belts with ridges that dig into grooves on a timing pulley.

Raul


: My "belts" folder has these options:

: 1. Optibelt makes polyurethane belts... they call their optibelt-ZRM a "supergrip" model: 630-628-8400

: 2. Mectrol makes urethane belts... check out www.mectrol.com.

: 3. Fenner Drives (of Fenner Manheim) makes belts... but they may be more into the custom area... www.fennerdrives.com

: 4. Voss makes belts, but they are mostly custom... 847-673-8900.

: Your bud,
: Andy B.

[archiver]

Posted by Andy Baker at 1/11/2001 9:45 PM EST


Engineer on team #45, TechnoKats, from Kokomo High School and Delphi Automotive Systems.


In Reply to: Must be "Timing" Belt!
Posted by Raul on 1/11/2001 3:50 PM EST:



Raul,

These are all timing belts, I believe.

Andy

[archiver]

Posted by Justin Stiltner at 1/12/2001 1:06 AM EST


Student on team #388, Epsilon, from Grundy High School and NASA, American Electric Power, Town of Grundy.


In Reply to: yep, they're timing belts
Posted by Andy Baker on 1/11/2001 9:45 PM EST:



: Raul,

: These are all timing belts, I believe.

: Andy

you might want to look into the materal that is sold by small parts that some teams put on their wheels last year. This stuff is sticky and is really strong. I cant rember the page or name but I know SP does sell it.

Justin Stiltner
Team #388
Grundy VA,

[archiver]

Posted by Matt Leese at 1/9/2001 11:50 PM EST


Other on team #73 from Edison Technical HS and Alstom & Rochester Institute of Technology.


In Reply to: Best Wheel Grip?
Posted by Eric Reed on 1/9/2001 11:07 PM EST:



The best way to give yourself good traction doesn't have to do with what kind of wheels you have. Instead it's going to rest more on where the center of gravity of your robot is. Put it squarely on top of your drive wheels and you should be good. Trying to improve the traction on the wheels is usually solving the wrong problem.

Matt

[archiver]

Posted by Joe Johnson at 1/10/2001 5:59 AM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: Best Wheel Grip?
Posted by Eric Reed on 1/9/2001 11:07 PM EST:



Along with this question, I have another.

If a train weighing 130 pounds is headed up a 14 degree incline pulling two 75 pound cars, what is the mininum coefficient of friction (mu) that the train can have between its wheels and the tracks?

My answer: .53 assuming all wheel drive -- it is worse if only one set of wheels is driving.

Teams that plan on just driving up that sea-saw without much thought are in for a surprise!

Joe J.

[archiver]

Posted by Raul at 1/10/2001 8:01 AM EST


Engineer on team #111, Wildstang, from Rolling Meadows & Wheeling HS and Motorola.


In Reply to: Mu Master 2000
Posted by Joe Johnson on 1/10/2001 5:59 AM EST:



Here is a slightly tougher but relevent question. Where does the CG have to be to ensure that with that much friction, you will actually pull the cars and not do a wheelie. The better question is: what is the minimum ratio of the distance from the floor to the hitch vs. from the center of the back wheels to the CG? And of course the height of the CG also matters on a 14 deg incline.

Raul

: Along with this question, I have another.

: If a train weighing 130 pounds is headed up a 14 degree incline pulling two 75 pound cars, what is the mininum coefficient of friction (mu) that the train can have between its wheels and the tracks.


: My answer: .53 assuming all wheel drive -- it is worse if only one set of wheels is driving.

: Teams that plan on just driving up that sea-saw without much thought are in for a surprise!

: Joe J.

[archiver]

Posted by Dodd Stacy at 1/10/2001 8:46 AM EST


Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.


In Reply to: Re: Mu Master 2000 - follow-up question
Posted by Raul on 1/10/2001 8:01 AM EST:



All the right questions, now how about the assumptions? Since our train is 3' long (maybe 2 1/2') and each 75 lb car (goal) is 3' long (still waiting for drawing dimension clarification) and our 14 degree incline is only 8' long ....... So, who's hanging off the end? Which end? Are we pushing or pulling? Cars on one end, or one on each end? And by the way, where is the train when the system cg causes the bridge to tip the other way?

I think it's going to be a lot of fun watching the various ways that multiple robots, and other "vehicles," make it over the bridge together - or don't. It's probably a good idea to make sure the bots don't get hung up when two wheels drop off the step at the end of a still-raised bridge. Hmmm, maybe some of us should make "wrecker"/towbots to clear the bridge.

Dodd

: Here is a slightly tougher but relevent question. Where does the CG have to be to ensure that with that much friction, you will actually pull the cars and not do a wheelie. The better question is: what is the minimum ratio of the distance from the floor to the hitch vs. from the center of the back wheels to the CG? And of course the height of the CG also matters on a 14 deg incline.

: Raul

: : Along with this question, I have another.

: : If a train weighing 130 pounds is headed up a 14 degree incline pulling two 75 pound cars, what is the mininum coefficient of friction (mu) that the train can have between its wheels and the tracks.

:
: : My answer: .53 assuming all wheel drive -- it is worse if only one set of wheels is driving.

: : Teams that plan on just driving up that sea-saw without much thought are in for a surprise!

: : Joe J.

[archiver]

Posted by Eric Reed at 1/10/2001 1:43 PM EST


Coach on team #481, NASA Ames / De Anza High School, from De Anza High School and It could be you!.


In Reply to: Mu Master 2000
Posted by Joe Johnson on 1/10/2001 5:59 AM EST:



I think the angle of the ramp last year was 15 deg, right? There were certainly robots that could push other full weight robots up the ramp. So it seems that it should be practical to move the goals. Is 75 pounds really the weight of a goal?

: Along with this question, I have another.

: If a train weighing 130 pounds is headed up a 14 degree incline pulling two 75 pound cars, what is the mininum coefficient of friction (mu) that the train can have between its wheels and the tracks?

: My answer: .53 assuming all wheel drive -- it is worse if only one set of wheels is driving.

: Teams that plan on just driving up that sea-saw without much thought are in for a surprise!

: Joe J.

[archiver]

Posted by Joe Johnson at 1/10/2001 9:56 PM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: Re: Mu Master 2000
Posted by Eric Reed on 1/10/2001 1:43 PM EST:



Our goal weighs 60 lbs.

If I recall, each small ball weighs about 1lb each and
the big balls weigh about 5lbs each.

A goal with 10 smalls and 1 big will tip the scales at
about 75 lbs.

Good luck to us all.

Joe J.

[archiver]

Posted by Joe Johnson at 1/10/2001 10:52 PM EST


Engineer on team #47, Chief Delphi, from Pontiac Central High School and Delphi Automotive Systems.


In Reply to: 60lbs + 10X 5lbs + 10X 1lb
Posted by Joe Johnson on 1/10/2001 9:56 PM EST:



The 60lbs of the goal did not have the tow bars on yet
AND we did not use "official" casters -- our are
perhaps a little lighter, not sure.

Finally, we used a bathroom scale... ...not exactly
traceable to the National Bureau of Standards ;-)

Better than nothing but not as good as it could be.

Joe J.

[archiver]

Posted by Jim Meyer at 1/11/2001 7:46 AM EST


Engineer on team #67, HOT Team, from Huron Valley Schools and GM Milford Proving Ground.


In Reply to: Forgot that tow bars are not on yet...
Posted by Joe Johnson on 1/10/2001 10:52 PM EST:



Would anyone be kind enough to share the height of the CG of an empty goal?

Thanks in advance.

[archiver]

Posted by Elliot Johnson at 1/18/2001 2:17 PM EST


Student on team #218, HP Robotics Team, from Highland Park High School and Double-E Inc..


In Reply to: Forgot that tow bars are not on yet...
Posted by Joe Johnson on 1/10/2001 10:52 PM EST:



Our completed goal weighs 75 lbs without any balls on it.

Elliot Johnson
Team 218
Double-E Inc. & Highland Park Robotics

[archiver]

Posted by Scott Strickland at 1/10/2001 1:27 PM EST


Engineer on team #21, ComBBAT, from Astronaut & Titusville High School and Boeing/NASA.


In Reply to: Best Wheel Grip?
Posted by Eric Reed on 1/9/2001 11:07 PM EST:



We have used the small rubber bumpers from Small Parts. They are normally used for the feet of computers etc. Use the one with a washer. Cost is fairly low. (can't remember the p/n)

We rivet them to our wheels. Replace them as the wear.

Incredible Traction with the carpet.


: We are looking for ideas to modify the wheelchair wheels or create new wheels. We want the most grip possible. Any suggestions?

: Thanks,

: Eric.

[archiver]

Posted by Joe Ross at 1/11/2001 3:57 AM EST


Engineer on team #330, Beach Bot 2001, from Hope Chapel Academy and NASA/JPL and J&F Machine.


In Reply to: Rubber Baby Buggy Bumpers
Posted by Scott Strickland on 1/10/2001 1:27 PM EST:



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