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-   -   Bouncing turns (http://www.chiefdelphi.com/forums/showthread.php?t=25797)

blindguyinanorg 22-02-2004 23:37

Re: Bouncing turns
 
Quote:

Originally Posted by Elgin Clock
Somoene actually suggested using a wax type substance like armor-all on the tires? Would that work, or be legal?

yes, anything to reduce the friction

there is another post about this(by me) but it ended up in the pnuematics section sence i said pnuematic wheels HA!

http://www.chiefdelphi.com/forums/sh...ad.php?t=25061

ChrisH 23-02-2004 11:35

Re: Bouncing turns
 
The Schmoebots had this problem as well. They solved it by simply removing the tires on one end and running on the rims. There's a little bit of slip from the different diameters, but it doesn't seem to cause any problems.

Random Dude 23-02-2004 11:35

Re: Bouncing turns
 
Quote:

Originally Posted by Elgin Clock
Somoene actually suggested using a wax type substance like armor-all on the tires? Would that work, or be legal?


Hmm. Well, I would think wax could be a bad idea, since it could(would?) rub off easily onto the carpet, something which FIRST would not like.

However, what does work, is wrapping some sort of material around the tires...

Collin Fultz 23-02-2004 11:57

Re: Bouncing turns
 
we had this exact same problem last year. the cause was too much top weight and too much traction. we looked like we were convulsing while turning. we could never figure out how to stop it and just kind of lived with it. on the bright side...we never lost a pushing match. good luck!

Peter Matteson 23-02-2004 14:03

Re: Bouncing turns
 
My team, 177, has perrenially had this issue we finally broke down and made omniwheels for the rear. Our experience shows that having lower friction in the rear wheels increases manueverabilty while retaining control compared to the fronts. Most teams who saw our bot at the UTC scrimmage can attest to it's speed and manueverabilty with these wheels. We were also never at a loss for traction.

Eric Bareiss 23-02-2004 14:16

Re: Bouncing turns
 
Quote:

Originally Posted by Elgin Clock
Somoene actually suggested using a wax type substance like armor-all on the tires? Would that work, or be legal?

No you can not do this, once again a case of "if you don't know don't answer"

<R15> Lubricants may be used only to reduce friction within the robot. Lubricants shall not be allowed to contaminate the playing field surfaces, balls, or other robots.

You can use anything that will stay on your wheels, tape, paint, glue. But nothing that will rub off and contaminate the field.

Greg Perkins 23-02-2004 14:24

Re: Bouncing turns
 
Quote:

Originally Posted by ChrisH
The Schmoebots had this problem as well. They solved it by simply removing the tires on one end and running on the rims. There's a little bit of slip from the different diameters, but it doesn't seem to cause any problems.


or make a wheel outa lexan or delrin ;)

Ruffryders1273 25-02-2004 15:46

Re: Bouncing turns
 
Quote:

Originally Posted by Jones571
This was a problem at the UTC scrimmage 716 was bouncing out of control they didn't have the problem as bad after taking most of the air pressure out of there tires.
We did have this problem but after our first match we deflated our tires to the recommended 35psi(instead of 50psi), we still get some bounce but only in low gear.

Kevin Karan 25-02-2004 16:07

Re: Bouncing turns
 
wax wont rub off. Though you would loose so much traction that you probably wouldnt be able to climb to the bar anymore.

gnormhurst 27-02-2004 17:51

Re: Bouncing turns
 
I assume everyone is talking about 4-wheel-based bots. I guess if you were surprised that it wouldn't turn well, the lesson is to think carefully before committing to a major design decision.

Our bot has only two wheels, midship, and plastic skids on the corners. It turns nicely in any radius we choose and turns on a dime.

And it can't climb the steps at all. Engineering is the art of making tradeoffs. We'll go for the bar from the side.

Has anyone built a bot with a rear-end differential and steered wheels like a car?

ngreen 27-02-2004 18:05

Re: Bouncing turns
 
Quote:

Originally Posted by Eric Bareiss
No you can not do this, once again a case of "if you don't know don't answer"

<R15> Lubricants may be used only to reduce friction within the robot. Lubricants shall not be allowed to contaminate the playing field surfaces, balls, or other robots.

You can use anything that will stay on your wheels, tape, paint, glue. But nothing that will rub off and contaminate the field.

Be nicer than that. You can use anything that will not rub off on the field. Armor-all when used right won't damage the playing field while making your tires a little slicker. I wouldn't reccomend it though. However tape may not be used. The only tape that is allowed is electrical tape as an electrical insulators. I don't want to be offensive about this but it is not good to post about someone else not knowing the answer and having incorrect statements in your own comments.

jparkteach 27-02-2004 19:53

Re: Bouncing turns
 
It has been posted elsewhere but our team came up with it early on during the design stage once we realized that we might have some problems turning. Zip-ties on either the front or the rear wheels. On all four wheels is overkill, you may want to put them on the wheels farthest from the center of gravity of your robot in order to keep as much traction as possible.

sanddrag 27-02-2004 19:53

Re: Bouncing turns
 
Tried armor-all like tire shine. It doesn't really help.

Team311 27-02-2004 20:04

Re: Bouncing turns
 
we added a caster that helps us turn. it lifts the front two wheels off the ground andit turns much better

DougHogg 27-02-2004 22:51

Re: Bouncing turns
 
We have struggled with this problem since we started 2 years ago.

Last year, we put zip ties, 1 every half inch or so, on the wheels at the lightest end which helped a lot.

This year, thanks to an idea that we got from Team 254 and Team 60 (which I understand originally came from Team 25), the problem is history.

The solution: 6 wheel drive with the middle wheels 3/16's of a inch lower than the other wheels. We turn on a dime and still have 6 wheel drive using chains. Basically our robot is rocking on the middle two wheels. We had to actually reduce the turning rate to make it more controllable.


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