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-   -   do the racks move? (http://www.chiefdelphi.com/forums/showthread.php?t=51145)

groves 07-01-2007 14:57

do the racks move?
 
yesterday people I spoke with agreed that the rack seemed mobile or at least able to spin. a've been reading and have not seen much information on this. the drawings don't seam to have casters.

Travis Hoffman 07-01-2007 14:58

Re: do the racks move?
 
http://www.chiefdelphi.com/media/photos/26156?

petek 07-01-2007 15:41

Re: do the racks move?
 
Quote:

Originally Posted by groves (Post 550059)
yesterday people I spoke with agreed that the rack seemed mobile or at least able to spin. a've been reading and have not seen much information on this. the drawings don't seam to have casters.

I presume you're asking "does the whole rack assembly move?" and <G07> says that it can and will be moved, but I haven't found any information on how it is moved; I'm guessing it just slides on the carpet. For non-moveable field elements, FIRST usually attaches to the carpet with velcro on the underside (e.g. Triple Play goals), but that wouldn't work in this case since the Rack gets repositioned at the start of each match. If there isn't some way of attaching it to the carpet we can expect that it will get moved by robot contact during the competition, too.

Wayne C. 07-01-2007 16:18

Re: do the racks move?
 
the rack just slides around on the carpet and is held in a rough position by the chains attached to the fixed central plate. As I understand it, they will give the rack a slight twist each time to reposition the prongs. That means the width of the side alleys will also be variable to some extent

The whole thing is quite heavy. I dont know if it is legal to grab it and keep it spinning (but we thought of that).

The spokes are somewhat rigid in place but if you jar them they will rock around.

jgannon 07-01-2007 16:48

Re: do the racks move?
 
Quote:

Originally Posted by Wayne C. (Post 550132)
As I understand it, they will give the rack a slight twist each time to reposition the prongs.

They do more than that... <G07> tells us that the rack will also be translated up to three feet from the center of the field before the beginning of the match.

paradoxal 07-01-2007 17:09

Re: do the racks move?
 
Quote:

Originally Posted by Wayne C. (Post 550132)
the rack just slides around on the carpet and is held in a rough position by the chains attached to the fixed central plate. As I understand it, they will give the rack a slight twist each time to reposition the prongs. That means the width of the side alleys will also be variable to some extent

The whole thing is quite heavy. I dont know if it is legal to grab it and keep it spinning (but we thought of that).

The spokes are somewhat rigid in place but if you jar them they will rock around.

G33, it is illegal to attach to any field structure, so no grabbing. and "robots may push or react against any element of the field, provided there is no damage or disruption of the field elements" so no, you cant purposefully move it

Cody Carey 07-01-2007 17:19

Re: do the racks move?
 
Quote:

Originally Posted by paradoxal (Post 550168)
G33, it is illegal to attach to any field structure, so no grabbing. and "robots may push or react against any element of the field, provided there is no damage or disruption of the field elements" so no, you cant purposefully move it


It depends on the definition of "Disruption", and since it is not in the manual, this will need to be clarified. "Disruption" could simply mean that you can't knock the rack on its side. I am assuming that there will be robots moving the rack on the field.

AV_guy007 07-01-2007 17:28

Re: do the racks move?
 
after being at kickoff and trying to move the rack we determined it would be almost impossible for a robot to move it any significant amount.

KDawg 07-01-2007 17:40

Re: do the racks move?
 
When the refs 'move' the rack in the middle at the beginning of the match, does the whole structure move or do just the legs take a spin?

I guess what I'm trying to ask is that can the whole structure be moved?

Thanks

Cody Carey 07-01-2007 17:41

Re: do the racks move?
 
Yes, they can move it up to three feet in any direction at the beginning of the match.

Greg Marra 07-01-2007 17:43

Re: do the racks move?
 
The rack is able to move, but it weighs a lot and is very difficult to budge. Don't plan on your robot being able to move it at all.

If you want to see video of people trying to move it, check out The Blue Alliance's Kickoff Coverage, where we show just how hard it is to do anything to move the rack.

Cody Carey 07-01-2007 18:02

Re: do the racks move?
 
Quote:

Originally Posted by Greg Marra (Post 550207)
The rack is able to move, but it weighs a lot and is very difficult to budge. Don't plan on your robot being able to move it at all.

If you want to see video of people trying to move it, check out The Blue Alliance's Kickoff Coverage, where we show just how hard it is to do anything to move the rack.

Could two, or maybe all three robots move it if they were pushing at the same time?

paradoxal 07-01-2007 18:10

Re: do the racks move?
 
Quote:

Originally Posted by Cody C (Post 550229)
Could two, or maybe all three robots move it if they were pushing at the same time?

then that would take away from the time you have to score,and besides, its best to have it in the middle, half of your ringers on behind you, and half are on the opponents side of the field

Cody Carey 07-01-2007 19:03

Re: do the racks move?
 
Quote:

Originally Posted by paradoxal (Post 550237)
then that would take away from the time you have to score,and besides, its best to have it in the middle, half of your ringers on behind you, and half are on the opponents side of the field

It would decrease the amount of time to get back from running across the field to grab ringers, and increase the amount of time for the opposing alliance to run across as well, since it would presumably be quicker to pick up from the opposing side than the human player, this would be an advantage.

Greg Marra 07-01-2007 19:22

Re: do the racks move?
 
Quote:

Originally Posted by Cody C (Post 550286)
It would decrease the amount of time to get back from running across the field to grab ringers, and increase the amount of time for the opposing alliance to run across as well, since it would presumably be quicker to pick up from the opposing side than the human player, this would be an advantage.

The Rack is physically chained to the floor. You won't be able to move it more than three feet from the center of the field.

Tom Bottiglieri 07-01-2007 19:25

Re: do the racks move?
 
Quote:

Originally Posted by Greg Marra (Post 550315)
The Rack is physically chained to the floor. You won't be able to move it more than three feet from the center of the field.

One foot translation in any direction.

sciencenerd 07-01-2007 19:42

Re: do the racks move?
 
Quote:

Originally Posted by Tom Bottiglieri (Post 550318)
One foot translation in any direction.

Quote:

Originally Posted by 2007 FRC manual
<G07> Center RACK position - After all six ROBOTS are in their starting positions and the DRIVERS, COACHES and HUMAN PLAYERS are in the ALLIANCE ZONE, the RACK will be moved (translated and/or rotated) to an arbitrary position so that the center of the RACK is within a 3 foot radius of the playing field center but the exact location and orientation of the RACK is unpredictable.

(bolding added)

It sounds like a 3' radius in this rule - although from this picture linked to above, it seems that, practically speaking, 1' may be closer to the mark.

Jack Jones 07-01-2007 20:08

Re: do the racks move?
 
Question:

How many refs does it take to move a Rack?

Answer:

Get out of a Rack, NOW!

;)

swamp_child 07-01-2007 20:16

Re: do the racks move?
 
supposedly there is a rule preventing a robot from moving the rack

KDawg 07-01-2007 20:21

Re: do the racks move?
 
Thanks guys.

Yea, I dont think a team would want to move the whole structure any which way, and I cant think of a reason why they would want to anyways.

Alan Anderson 07-01-2007 22:37

Re: do the racks move?
 
Quote:

Originally Posted by KDawg (Post 550414)
Yea, I dont think a team would want to move the whole structure any which way, and I cant think of a reason why they would want to anyways.

I can think of one: spin it around so the "other" side is facing your alliance station. That way you can see better to fill any empty spider legs with your ringers more easily.

However, the rack is very heavy -- several hundred pounds -- and I really don't think it's going to move during a game.

WeldedHarlequin 08-01-2007 21:00

Re: do the racks move?
 
Remember, the plywood Racks that were at the kickoffs were really heavy, but the same structure made out of aluminum tubes won't be as heavy.
But I agree, I really can't see how it would be feasible to move or rotate the Rack in the middle of a match.

Plus, that wouldn't really be in the spirit of FIRST, now would it... ;)

AV_guy007 08-01-2007 21:08

Re: do the racks move?
 
Quote:

Originally Posted by WeldedHarlequin (Post 551620)
Remember, the plywood Racks that were at the kickoffs were really heavy, but the same structure made out of aluminum tubes won't be as heavy.

while them may not be as heavy trust me it was heavy :eek:

Moose 08-01-2007 21:51

Re: do the racks move?
 
I have heard the rack is on a "lazy susan" and it will be given a spin after robots are placed in their starting positions making camera systems essential in finding it.

ahecht 08-01-2007 21:57

Re: do the racks move?
 
Quote:

Originally Posted by swamp_child (Post 550402)
supposedly there is a rule preventing a robot from moving the rack

Instead of saying "supposedly there is a rule", which is just a way of saying "I think this is how is should be, but I don't know", how about citing the actual rule. People who imply they know more than they do can be very dangerous (I should know, one almost killed me last month).

Nawaid Ladak 08-01-2007 22:46

Re: do the racks move?
 
actuallly moving the rack is the ideal stratagey

if you were to say move it right in front of an alliance station, it would not only disrupt the END GAME for your opponans but block ff at least two colums of legs, now if you were to move this into a corner, it would eliminate four legs,

so in theory, if you have four rows covered with ringers, those can't, and probally wont be touched,

the best offense is a superb defense

EricH 08-01-2007 22:50

Re: do the racks move?
 
Quote:

Originally Posted by FreedomForce (Post 551741)
actuallly moving the rack is the ideal stratagey

if you were to say move it right in front of an alliance station, it would not only disrupt the END GAME for your opponans but block ff at least two colums of legs, now if you were to move this into a corner, it would eliminate four legs,

so in theory, if you have four rows covered with ringers, those can't, and probally wont be touched,

the best offense is a superb defense

Nice try. Did you read Section 6.2 The Rack yet? You can't move it more than 1 foot in any given direction. Also, you would have to have a drivetrain capable of moving 600 pounds at once (such as team 71's 2002 design, which is now illegal).

BigRed 08-01-2007 23:18

Re: do the racks move?
 
Not that it really matter to my team's strategy, but in section 6.2.2 "The Rack" it says the "The platform is frimly attached to the floor of the Playing Field. The slack in the chains connecting the structure to the platform permit the RACK to translate approximately One Foot"
while rule G07, as stated before, says that "the center of the RACK is within a 3 foot radius of the playing field center..."
So which one is it, or is there something I'm missing?

Wetzel 09-01-2007 02:12

Re: do the racks move?
 
Quote:

Originally Posted by Alan Anderson (Post 550649)
However, the rack is very heavy -- several hundred pounds -- and I really don't think it's going to move during a game.

The full rack weighs over 600 pounds. It will take several strong types to move it at the beginning of the match.

Wetzel
Please read the rules.

Psychoflood 09-01-2007 09:23

Re: do the racks move?
 
I'm confused about the apparent contradiction in the rules... in the rules it says that the rack can be moved approximately 1' in any direction, but it also says that at the beginning of the match the rack may be anywhere up to 3' away from the center of the field....

The picture seems to represent 1' as the more realistic distance..

KevinH 09-01-2007 12:03

Re: do the racks move?
 
I was told that the rack weighs ~400 lb, and that it could be moved if robots can figure out how to move/turn ~400 lbs of metal.

Elgin Clock 09-01-2007 12:22

Re: do the racks move?
 
Quote:

Originally Posted by Moose (Post 551665)
I have heard the rack is on a "lazy susan" and it will be given a spin after robots are placed in their starting positions making camera systems essential in finding it.

That is false, I thought that at first, but seeing the actual metal rack at the kickoff in NH it is not on any lazy susan type system.

It's more representative of a "Chain Chomp" from Super Mario Brothers:

http://content.answers.com/main/cont..._chompSMB3.PNG

Where the chain holding the "chomp" or in this case the Rack to the floor will only allow 1' of movement from the center of the post on the base:

http://www.chiefdelphi.com/media/photos/26156

BandChick 09-01-2007 12:26

Re: do the racks move?
 
400 lbs, vs. 600 lbs isn't really anything worth squabbling about. It's still going to be next to impossible to move.

And John, to answer your question, the rack itself can be repositioned at the start of every match within a 3' radius. The 1' movement is the distance each set of spider legs is capable of moving from the center of the platform. So, if you move the rack over 2' feet, the spider legs can still be moved up to 1' away from the center. If you don't move the rack at ALL, the spider legs can STILL be moved up to 1' away from the center.

Hope this helps!

carbuff 09-01-2007 12:54

Re: do the racks move?
 
at the beginning of the match they spin the rack so it is harder

Psychoflood 11-01-2007 14:03

Re: do the racks move?
 
ah okay i get it now, thanks a lot Sara!


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