I was doing some traction tests with a stationary robot (measuring the pull of the robot at different drive speeds). I noticed about halfway through that there was a smell of urine with a hint of burning plastic. Upon closer inspection, I found the regalith to be wearing away, leaving small piles of dust. It had by no means worn flat, but the fact that the floor wears away before the wheels worries me for two reasons:
Regalith is a fiberglass composite. That effectively means it leaves fiberglass dust when it wears away. I handle fiberglass almost as carefully as I handle asbestos (that is, not at all, whenever possible).
At the arena, the robots all start in approximately the same position. If a majority of the robots start by spinning out as fast as possible to gain the most traction, these starting positions will soon have small piles of dust there, affecting both the air quality and the traction (or lack thereof).
I was finding that, as I sped up the drivetrain, the traction oscillated between 10lbs and an increasingly higher pull (20lbs when I stopped). I hypothesize that if the floor did not wear, then the traction would have remained at a little less than 10lbs, however, I have neither the funds nor approval for continued destructive testing.
That’s interesting. I’m sure FIRST must have tested this before. Maybe they add something that doesn’t affect the coefficient of friction but reserves the playing field’s condition
Greatest traction is achieved when starting out by applying torque to the point just before wheel slip (Dynamic vs. Static Friction). If you are burning out at start, you are not going anywhere if the surface is intact. I suspect your traction increase may be due to the material the rogolith is adhered to is being worn through. It may have a higher CoF than the surface film. FIRST may have to clean these areas between matches, and may even have to replace sheets in these areas if it truly is a problem. It will be something to watch for while we are testing, and report to FIRST as a potential problem. Everyone should take note, and Thanks or the observation. :ahh:
These spots will be very hard to replace individually because the official playing fields are made of three 8 X 50 foot rolls of this material and not individual sheets that we are using.
this could be a problem… I am not as worried about the damage to the field as much as I am worried about the potential of fiberglass dust to be in the air around the fields…
I would not think it would be very much…but it does not take much.
Hey, we just did our first test woth the robot today, we put some weight on to make about 120 lbs, and we found dust on the wheels. I think the wheels were picking up the dust created by the floor. And we also found that the dust that stuck to the wheels, and greatly decreased the traction.
Dust from wear is probably the biggest reason to not allow
vacuum effect robots, as these would suck the dust from the
floor and pump it into the air. It may be a good idea for the
field to be equipped with a HEPA vacuum, or some other dust
collector, to clean the plastic surface when needed.
You are not alone with your concerns and results. We experienced that same thing the first time we tested the robot. We immediately stopped when we started to smell the burning plastic.
Houston we have a problem.
To make matters worst, I’m fearful of using our hallways or gym. Any sharp turning or spinning and the robot leaves marks in the wax finish. I can not afford to make enemies with the custodial staff. :ahh:
We went out and sacrificed another $150 in FRP in an attempt spread out the damage and safety risk :mad:
Anyone have any idea what to do with this material after the season?
Are you sure the powder isn’t coming off the wheels? We did a weighted test this weekend in our gym and noticed that for the one drive we did with weight on the bot, it left big white streaks across the tan/brown gym floor. When we wiped the streak, we were left with very fine white powder, leaving us to conclude it was the wheels, and not the gym floor, that was the source.
The only markings left on our Regolith after testing (particularly the sideways push)](http://www.youtube.com/watch?v=1em_E3L0_M0) were black marks. The black marks won’t come off and I believe are the wear of the field. I noticed the wheels themselves had some scratches them, and had a fine powder of something on them. I cleaned them before I investigated it.
Really, just get a “team-owned” mop. If practice sessions leave any marks on the floor, clean them up yourselves and don’t leave them behind for the janitorial staff. You will make friends with them, they will appreciate it, and everything should be cool. The staff at our school have been wonderful. We got them involved many years ago with what we were doing. We let them drive the robot around and promised to always clean up our messes before they would ever have to. Ever since then, they have been very accommodating of us.
…and it helps to feed them anytime your team hosts a pasta dinner for a fund raiser like we do. Or leave them the left over donuts…like THAT is ever gonna happen!!
where did you get this information? On the field at the kickoff these sheets were exactly the same 4X8 sheets we can buy…they were held together with what looked like a white masking tape.
The gel would wear for a while before you get down to the fiberglass. Probably the texture is mostly or all gel, and the backing is fiberglass. You could carefully sand a corner of the sheet and find out quickly. It can’t be any worse than working on a Corvette! (ugh)
Greatest traction is achieved when starting out by applying torque to the point just before wheel slip (Dynamic vs. Static Friction). If you are burning out at start, you are not going anywhere if the surface is intact. I suspect your traction increase may be due to the material the rogolith is adhered to is being worn through. It may have a higher CoF than the surface film. FIRST may have to clean these areas between matches, and may even have to replace sheets in these areas if it truly is a problem. It will be something to watch for while we are testing, and report to FIRST as a potential problem. Everyone should take note, and Thanks or the observation. :ahh:
