Team Update #1

FIRST General Forum
#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??

#56

The change to <R18> is the one that irked me…

“The Trailer Hitch must be located on the BUMPER PERIMETER of the ROBOT structure…”

Our Design Team was looking at mounting the Hitch further in the base of the robot, pulling the trailer tight against the rear bumpers of the robot, making the trailer a little more controllable (if you can really say that with this game). Now, THAT’S out the window!

Well, as long as the GDC gets rid of <G14> and they don’t limit our creativity anything further, I can at least get them to stop being annoyed at the whole thing…me too, for that matter.

#57

When I walked on the field in NH at kickoff, you could feel it move. The is a disconnect between the frp and what ever is below it. This is with a lot of people standing on it.

#58

My thoughts exactly. It looks like they want everyone to be a shooter. Given the difficulties with that in 2006, and the more random squishy nature of the Orbit balls, I was hoping to see some very effective dumper designs. It would be hard enough to work within the 28x38 restrictions; you’d have to make your base slightly smaller so you could have a 4-6" chute that extended over your robot’s and the trailer’s bumpers.

I’m not upset at no-goaltending and no-descoring rules, as it would have been difficult to do within the 28x38 footprint anyway.

I’m not a mentor, so I’m not on the list. This Update came out on a Tuesday; last year the schedule was Tuesdays and Fridays. Were teams informed to look for Updates on this schedule this year?

#59

Team Update #1

1- You will build team #??? robot from 2006
no other updates this year
:ahh:

#60

I’d like to see a specific statement in Q and A or a team update that “suck down” is specifically illegal before we completely abandon the idea, but based on Bill’s statement, I suspect that clarification will come.

#61

I heard a rumor that they will hold down the surface with double sided carpet tape underneath and fiberglass tape at all of the seams and edges. We are using 4 x 8 sheets and have 3/4 of a field put together. We are only using the fiberglass tape and the field doesn’t move. The tape is clear with fibers going the long way and sideways like a grid. I found it in the paint department at Home Depot. The double sided tape is in the flooring / carpet department at Home Depot.

We have driven about 6 hours on the floor and it is holding up just fine. All of the forces this year are much, much lower than in previous years.

#62

I think its a little far to call it unprofessional. You have a set number of game designers that have been designing a game for so many months. When that set of people look at something for so long of course you are going to miss something.

Then when you release this game to 10,000+ critics. The game is going to be picked apart and strategy and robot ideas are going to come up that they did not even think of.

I think FIRST does a great job with their updates and trying to keep the game fair. Granted I do like having a defensive robot makes the game exciting. Thats why 2003 game stack attack was one of my favorites. that last 30 seconds of the game, all hell broke loose trying to get your robot on the ramp to get the extra 50 points.