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-   -   Wheel Wear (http://www.chiefdelphi.com/forums/showthread.php?t=71647)

Andrew Y. 08-01-2009 22:56

Wheel Wear
 
ok so we are all going to test our bots. Some of us dont have the field surface and we may be practicing on our shop floor. soo heres my questions

how do yall think first will deal with worn wheels due to testing?

CDH Jeff 08-01-2009 23:02

Re: Wheel Wear
 
In the rules it says <R06>"The surface tread of the ROVER WHEELS may not be modified except
through normal wear-and-tear."

Geshamakina 08-01-2009 23:06

Re: Wheel Wear
 
The main question is...how are they going to be able to tell wether it was through "normal" wear-and-tear??? some bots may wear out their wheels more or not at all, and we all want any added friction. How are they going to be able to tell if it was done on purpose or not??? honesty is needed here.
:p

Iceman1330 08-01-2009 23:12

Re: Wheel Wear
 
I'll also direct you at <R06>

"The intent of this rule is that the ROVER WHEELS be used in as close to their “out of the box” condition as possible, to provide the intended low-friction dynamic performance during the game"

Anyone hoping to wear their wheels before the competition as an advantage for traction needs to give themselves an ethics check. FIRST rules, as we all know, are about intent, not lawyering.

In your case, it might be unavoidable wear and you might not have the budget to replace the wheels. However, if you know wheel wear is going to be an issue, pick up some more if you can to comply with the intent of the rule.

Andrew Y. 08-01-2009 23:17

Re: Wheel Wear
 
haha gotcha... man i need to change my train of thought. in FSAE racing, its allabout bending and pushing to rules to get MAX performance lol:yikes:


hmm, we only have our shop space to run. Now its not as rough as sidewalk concrete but its not the smoothest surface ever. And i know ALOT of teams that only have a parking lot to run...:ahh:

Prontopwnage 09-01-2009 17:58

Re: Wheel Wear
 
lolz you could wear your wheels down so its really rough and you would gain a bit of traction but not much...:eek:

But this really a techicality... so if you do this you can get skrewed over by the judges... and have to switch wheels, so... idk

Hanna2325 09-01-2009 18:58

Re: Wheel Wear
 
I'm sure what ever u guys are doing will be considered "normal" but if ur planning on some intense driving practices u probably could order more wheels just to be safe.

Otaku 09-01-2009 19:39

Re: Wheel Wear
 
If you guys want a good surface to test on, I suggest some clean tile flooring that is in most schools inside. We had a sample of off-brand regolith and compared it to our tile flooring and got similar numbers.

I see no reason why a school wouldn't have tile somewhere.

If it's an issue of "there's other people there", just wait until after they've left and then go use the room. Just make sure to leave it in the same condition you used it in -- wouldn't want to get in some trouble because you messed it all up. :yikes:

JesseK 09-01-2009 19:46

Re: Wheel Wear
 
If you are trying to wear your wheels for more traction at a competition: good luck! You will more than likely wear one more than the others, which means one of the wheels probably will not touch the surface. On top of that, it's fairly difficult on this field to keep all four wheels with the same amount of traction if you modify them. (A mu difference of 0.01 with these wheels is a +- 20% amount of traction...)

So, 'normal wear and tear' from your shop -- I wouldn't worry about too much. I'd imagine that the GDC expects that everyone will want to practice ahead of time and that not everyone has an ideal field to do so.

Mike Wittman 09-01-2009 19:55

Re: Wheel Wear
 
Quote:

Originally Posted by Prontopwnage (Post 796956)
lolz you could wear your wheels down so its really rough and you would gain a bit of traction but not much...:eek:

But this really a techicality... so if you do this you can get skrewed over by the judges... and have to switch wheels, so... idk


I have to take issue with your "Skrewed over" comment. The judges and refs are there to uphold the rules not Skrew people over. As a matter of fact I find them to be very helpful to teams that don't satisfy the rules.

Clayton Rogers 09-01-2009 20:01

Re: Wheel Wear
 
Quote:

Originally Posted by Otaku (Post 797065)
If you guys want a good surface to test on, I suggest some clean tile flooring that is in most schools inside. We had a sample of off-brand regolith and compared it to our tile flooring and got similar numbers.

I see no reason why a school wouldn't have tile somewhere.

If it's an issue of "there's other people there", just wait until after they've left and then go use the room. Just make sure to leave it in the same condition you used it in -- wouldn't want to get in some trouble because you messed it all up. :yikes:

We tested on the school floors and got .25 co-efficient of friction and also tested on the actual surface and got .07. So we concluded that the school floor were several times stickier than the actual surface, but still very slippery and probably still good for practice. Also note that our school floors were not very clean and had some dust/dirt.

Kyle Love 09-01-2009 20:01

Re: Wheel Wear
 
This will more then likely come down to the head inspector (in many cases) at the regionals/Champs. "Normal wear" in my book, is light scratching of the tread area, that would resemble a razor slit. There should be very few side to side "slits" and a fairly constant diameter slit. These slits will be hard to be done without testing, because as some have found out, the slits tend to be spuratic and very inconsistent on the tread of the wheels. In a nutshell, I believe the only issues that inspectors will have, is with team who have altered their wheels, gracious professionalism will need to be used by teams to make sure that they do not alter their wheels to appear "more used" then normal.

JesseK 09-01-2009 20:10

Re: Wheel Wear
 
Quote:

Originally Posted by sejeff (Post 797087)
Mike is right, the judges will do everything in their power to help you get approved and out on the playing floor, that's why I love them.

I completely agree. They know that you've put 6 weeks of blood, sweat, and <sometimes> tears into the thing...so not being able to play at all is definitely not what they want. Between all of the available resources, you will somehow find a compromise and be able to play so long as you agree to their terms...which are always in my experience within what the GDC puts out.

1885's own example:
In Atlanta '08, on Friday a ref (who was also an inspector on Thursday) noticed an angle connection on our radio modem serial port. We put our controller 1.5" from the rear of the robot. No big deal we thought, since we could put an angle on the radio modem connector and connect the radio while staying within the dimensions. Little did we notice that the connections themselves were not allowed to be modified in ANY way, which the ref pointed out to us with the rulebook. We made it through 2 regional competition inspections and Atlanta inspections without a single word to us, so our plea to the head ref in Atlanta was for us to keep the angle connector on. His compromise in return was that we were not allowed to dispute a match in which our robot stopped responding due to communication issues, as was his interpretation of the intent of the rule. We were allowed to compete if we agreed, which we did. Believe me, we're triple checking our compliance with the specifics this year!

907eyci 09-01-2009 22:38

Re: Wheel Wear
 
well for testing we had a good idea of a hockey areana.. but we are kinda in Canada so they ant soo hard to find up here.

CraigHickman 09-01-2009 22:42

Re: Wheel Wear
 
I have a serious problem with some of the logic presented in this thread. A true FIRST student would hear that the wheels gain traction as they wear, and rather than thinking pushing the rules to the max, they'd see that this REALLY means. Folks, design your robots to allow easy swapping of wheels. If FIRST sets a max amount of wear, you don't want to have to take your entire robot apart to change out a few wheels.


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