Team Update #1

FIRST General Forum
#36

I’ve explored the descoring topic a bit on my own, and I haven’t really found a really good way even before this prohibition…though remember, marketing major.

No intelligent team will go through an event without at least an attempt at a dumb run-the-heck-away-from-here routine. I don’t know whether we’ll see much robot-on-robot scoring in autonomous, but I could picture a fun round of jockeying for position–imagine a couple of robots double-teaming an opponent back into the corner, near-ideal conditions to let the human players pick a few off. (Or the same idea could bolster a partner’s attempt to score a few balls autonomously.)

I fully expect things to remain quite interesting.

#37

Um. No. They specifically ruled out Chapparell style sucking devices.

#38

Um, no, they didn’t. Jim, who may be on the GDC but is not the rulebook, stated that they are illegal because they damage the floor. I honestly don’t see where he’s coming from-perhaps skirts too low might scratch the floor, or something. But if you don’t damage the floor, there is nothing illegal about those systems.

#39

I think you mean Bill.

Incidentally, the GDC is the Supreme Court of FRC right now. (They are also the Legislature and the executive branch.) So if one of them says something about a rule, you might want to listen up. If Bill posts something, I’m willing to bet that it’s also the opinion of the rest of the GDC.

#40

Man, the fact that you have to stay within the vertical projection of the bumpers really inhibits the ability to create an effective dumper… you have to get the balls going about 4 inches from the dumping mechanism in order for them to actually land in the trailer. I actually had a really long discussion with a mentor about using a rotating hatch, similar to the mail deposits where you pull down on the handle insert the letter and gravity causes the letter to fall into the box when closed again, but in reverse. The idea was that when retracted, contact would indeed stay in the bumper zone, but it would extend beyond that for just a second to unload balls, and now that idea’s moot. </rant>.

#41

I’ve about decided that it will be illegal, because if used effectively, it would lift the thin, slick stuff from the floor. I’ll be following this pretty closely, though.

#42

Just to clear my mind… The robot can still pick up balls as long as the ball picker remains inside the starting configuation.

#43

Pulling a 1 PSI vacuum over a 20"x20" section will produce 400LBS of force pulling on all surfaces (Ideal gas laws). As such, while your robot may see a 400 LB gain in nominal downward force, you will also create a 400LB nominal upward force on the flooring which is only 0.090" thick plastic. This, most likely, will cause the floor to bow or even break.

We, too, were considering pulling a vacuum below the robot to increase our traction. We decided to wait on this strategy until we knew whether or not the floor could take such abuse … apparently it cannot :frowning:

#44

Maybe, I hadn’t really thought of that. I’m not really sure how the Glasliner is placed on the carpet-I can’t imagine they just drop it on and leave it at that, because it would take far less than a fan to dislodge it then. Does anyone know how they’re going to make the playing surface?

#45

I don’t know yet. I’ve heard that they don’t know either. Next up for the GDC field guys: How on earth do we attach the Regolith?

I’m sure something will come out and (hopefully) be released to teams eventually.

#46

Industrial Velcro has worked well in the past for anchoring stuff to the carpet. The anchor on the Rack n Roll rack, for example, was simply a steel plate with Velcro on the bottom that engaged with the carpet. McMaster sells a velcro “hook” side that can withstand 3psi in pull-apart pressure and 23psi in shear.

#47

so they have disallowed suction, what about a blower with an intake from the sides? a blower out the top with intake on the sides, rather than the bottom. I think you could still get a decent amount of downward force just from upward airflow (though I haven’t done any math to back this up, just an idea)

#48

I’m glad my team’s current design is not affected by these clarifications, but I do think this is a little restrictive. I’m glad for the goal tending rulings (because covering goals with plates would have led every finals to a 0-0 four match tie) but preventing any extension beyond the bumper zone forces teams to either dump or shoot balls to score (of course, this is probably the intent of the rule).

And don’t think defense is dead because of Update #1. If I don’t see AT LEAST one pinball style disruption robot I will be severely disappointed in teams this year. Being fast and unpredictable is almost as effective as sticking a sheet of cardboard over a goal (and a heck of alot more exciting for those of us that don’t watch the paint-drying channel).

#49

At the Kickoff here in washington the guy Kevin Ross (who is incharge of Firstwa) said that the drawings that he recieved which came from first did not mention how the material was secured)

#50

If your coefficient of friction is .05, you would get 1/20 of your
down force from the upward directed blower turned into traction
at the wheels. Is there a better direction for the blower, if it
is allowed?

Eugene

#51

The floor material is not exactly thin, flexible, or breakable. It’s about 35 lbs. per 4x8 sheet (the competitions will use 50’x8" rolls, very heavy), and definitely would not lift with any amount of suction on a 28x38 robot. I think their rule clarification was specifically targeted at the potential traction benefit, and not associated with any sort of potential damage to the floor.

To think that avoiding floor damage would make your robot legal is probably incredibly optimistic - trust me–nothing will damage this floor…

#52

I found the material spec’d to be thin flexible and breakable, while the sheets are heavy the material is not that robust, as we’ve already had a corner break off that got hit sideways from a drifting bot. This material would also not take kindly to roll form as it would most likely fracture.

just my experience with this FRP

plus suction is commonly used in industry to manipulate large sheets of material.
I envision if it was allowed a team with enough development could produce significant downforce.

also Bill says dont do this

3) Don’t spend time attempting to develop a vacuum car system like Jim Hall’s sucker Chaparral car. Even a slight suction over the base of the robot will damage the field surface and you don’t want to do that (See the 2009 FIRST Robotics Competition Manual

straight from bills blog

#53

Fair response, except that I’m unclear how a corner could be caught if the field is taped/adhered sufficiently. I transported by hand a full field worth of this material for the Wisconsin kickoff field demo, and I was shocked at how thick and heavy this stuff is. If the only part of the robot contacting the surface is the the “slick” wheels, as the rules dictate, It’s unclear how we could possibly damage the field, unless your vacuum was able to pull free any tape holding the pieces together…

#54

the pieces were just laying on the floor, i was just using that as a reference to overall durability.

If the sheets are simply attached at the edges i can see a vacuum capable of pulling up the middle and flexing the sheet, it all really depends on how FIRST decides to do the final assembly.

#55

Perhaps we saw different materials… With the stuff I worked with at the WI kickoff, I’m not sure 2000 lb would lift the middle of a 4’x8’ sheet…

Maybe someone can comment on the “officially specified” material and how heavy/light/thick/thin/flexible/brittle it is??