View Full Version : Defensive Strategies
wizardofoz
05-01-2009, 09:22
As long as you stay within the limits on dimensions, is there anything to keep the robot from reaching into the goal to get balls out?
I was thinking of a conveyor system with hooks that would reach into the goal.
Given the 10" tongue on the trailer, and the requirement that the trailer hitch be on your outer edge, that means you have to build your robot in <28" so you can have 10" of reach on some manipulator. Realistically, your drivebase has to be quite short, and given the size of the controls etc, that wont be easy, never mind that such a manipulator would throw your CG way out to lunch.
The way I see it, no, theres nothing stopping you, aside from the logistics of doing it and staying inside the 28x38x60 box.
If there are more balls in the trailer, less can be put in. If you remove balls, you have to balance that with the possibility that you can now have more points scored against you.
I would personally say that the fact that a "moon rock" is put in at the beginning is a great advantage for the end of the match when there is less room for a "super cell".
Edit: Removed my misinterpretation of <G07> descored balls not being counted.
The best defensive strategy I've seen thus far is a goaltending bot that prevents the balls from being scored at all.
Keep in mind that Balls removed from your trailer still count against you, and if there are more balls in the trailer, less can be put in. If you remove balls, you have to balance that with the possibility that you can now have more points scored against you.
I would personally say that the fact that a "moon rock" is put in at the beginning is a great advantage for the end of the match when there is less room for a "super cell".
please quote the rule where this came from?
Tetraman
05-01-2009, 10:01
The best defense is constant motion
pfreivald
05-01-2009, 10:02
The best defensive strategy I've seen thus far is a goaltending bot that prevents the balls from being scored at all.
I'd be interested to know how this might work, given that we are unable to extend out past the 28"x38"60" boundary this year... How can you tend a goal if you can't extend above or over it?
Patrick
Tetraman
05-01-2009, 10:05
please quote the rule where this came from?
It's not written in the rule book...but it is assumed though different rules.
<G07> B. If a TRAILER tips over, the points SCORED for that TRAILER at the time it was tipped will be preserved for the remainder of the MATCH.
I'm with IndySam, please quote such a rule. I have read the manual many times and seen no such indication that descoring by any means other than tipping is invalid.
There have been CAD drawings on another thread showing a bot with a very short drivebase that COULD cover ~50% of the trailer, IF a U shaped robot is allowed to have its trailer hitch on the inside of the U (unlikely). Possibly you could add a big CIM driven fan, to help blow balls away from the remaining 50% of the goal, but I think this strategy will be effectively outlawed anyway.
EDIT: <G07> makes no mention of descoring not counting, only that tipping your own, or an alliance partners trailer (or even the other alliances, really) will not descore the balls already in it. I imagine this is because the GDC expects there will be some accidental trailer tipping, via high speed collisions due to the low mu.
BigWhiteYeti
05-01-2009, 10:13
If at the end of the game you really needed to prevent opponent scoring, just do some donuts on the slippery floor. A spinning robot is going to be almost impossible to score on.
I'd be interested to know how this might work, given that we are unable to extend out past the 28"x38"60" boundary this year... How can you tend a goal if you can't extend above or over it?
Patrick
Who says you have to get outside the footprint to extend over it?
Stephen Kowski
05-01-2009, 10:22
It's not written in the rule book...but it is assumed though different rules.
<G07> B. If a TRAILER tips over, the points SCORED for that TRAILER at the time it was tipped will be preserved for the remainder of the MATCH.
....and if you don't tip it over and just remove balls?
By the same token, whats to stop you from building a <28x38x60 robot, and building a descoring mech on it and descore from your alliance partners trailers?
I'm with IndySam, please quote such a rule. I have read the manual many times and seen no such indication that descoring by any means other than tipping is invalid.
Same here. The real question is whether this would be considered illegal "outside the bumper zone contact". That's where I see the GDC most likely to rule it out, particularly using <G32> parts E and F.
On the other hand:
The ARENA includes all elements of the game infrastructure that are required to play Lunacy: the CRATER, the ALLIANCE BASES, the OUTPOSTS, the FUELING STATIONS, the PAYLOAD TRAILERS...
Arena Interaction –ROBOTS may push or react against any elements of the ARENA, provided there is no damage or disruption of the ARENA elements. With the exception of a ROBOT towing a TRAILER, ROBOTS may not grab, grasp, grapple, or attach to any ARENA structure.
IMO, <G29> doesn't say anything about this. You're not grabbing, grasping, or grappling the TRAILER (an ARENA element), you're reaching into it, which is not mentioned, and therefore just fine.
EDIT: also, the game pieces themselves are not considered ARENA elements, and therefore grabbing, grasping, or grappling those is just fine.
I really don't see a way to stop the other team from scoring on you. You could be able to put a lid on your trailer if you still fit in the dimensions but that is all your robot would really be able to do. I really think the best defense is going to be a good offense. Controlling the balls and making sure that you make them in the other alliances trailer before they make them in yours.
BigWhiteYeti
05-01-2009, 13:30
What if you just backed yourself into a corner of the arena and used your robot to block your goal? That could be useful end-game to prevent being supercelled by the other alliance.
What if you just backed yourself into a corner of the arena and used your robot to block your goal? That could be useful end-game to prevent being supercelled by the other alliance.
not a bad idea but there is no real corner.
What if you just backed yourself into a corner of the arena and used your robot to block your goal? That could be useful end-game to prevent being supercelled by the other alliance.
Depends on how good the human players were. 1073 won a playoff match in 2004 when the human player threw a playground ball into the goal from clear across the field at the last second.
But I agree, this is not a bad endgame strategy if you have no other defensive options (i.e. no lid, etc).
e: you do have to keep in mind that there is a red payload specialist on the side of the field and vice versa...there is no location for the robot to be that is more than 20 feet away from a human player...
Travis Hoffman
05-01-2009, 14:37
Just like 2006, having an alliance smart enough to know when NOT to chuck balls onto the field, missing their targets and providing the opposition more "ammo" in a fruitless, aggravating display of dumb is one of the better defensive strategies you can employ. Yeah, it might look cool to the crowd, but strategically, it's lame.
Deny the opposing alliance as much scoring "ammo" as you can. Conserve your ammo until the opportune time to unload it for maximum gain, or there's so little time left, the opposing alliance cannot "steal" it.
IMO, <G29> doesn't say anything about this. You're not grabbing, grasping, or grappling the TRAILER (an ARENA element), you're reaching into it, which is not mentioned, and therefore just fine.But as soon as you start restricting its motion from the inside, I'd call that some form of attaching to.
Realistically, I think this will end up in Q&A very quickly. I would expect that the answer would be something to the effect of "As long as no rules on contact outside the bumper zone are violated, it's fine."
Which then means that all one robot has to do to get you in trouble is tangle you up. If it's done enough, you have to modify your design.
You could be able to put a lid on your trailer if you still fit in the dimensions but that is all your robot would really be able to do.
What makes you say that?
Nawaid Ladak
05-01-2009, 16:51
Keep in mind that Balls removed from your trailer still count against you, and if there are more balls in the trailer, less can be put in. If you remove balls, you have to balance that with the possibility that you can now have more points scored against you.
I would personally say that the fact that a "moon rock" is put in at the beginning is a great advantage for the end of the match when there is less room for a "super cell".
as of now, and i hope moving forward, that is inncorrect information, unless you can show a rule that spicificly states this situation
It's not written in the rule book...but it is assumed though different rules.
<G07> B. If a TRAILER tips over, the points SCORED for that TRAILER at the time it was tipped will be preserved for the remainder of the MATCH.
your comparing apples to oranges. totally different situations.
Bigflip2073
05-01-2009, 23:58
I was thinking about this for a while
how about using air cannons to deflect cells?
How much would it take to actually have an effecton an incoming cell?
Most likely there wouldnt be enough pressure and volume for there to have an effect on an orbitball.
however i dont think it has been tried
as of now, and i hope moving forward, that is inncorrect information, unless you can show a rule that spicificly states this situation
your comparing apples to oranges. totally different situations.
Apologies for the incorrect information, however if you are allowed to descore, then, I would assume descoring from allies is also allowed. If from yourself, then why not your teammates? This would a low a single robot on you team to be designated a "descorer" perhaps with a conveyor-hook settup to simply go up to allies and remove balls through the grates of their trailers. This seems to be against the spirit of the competition, leading to my previous point.
I still believe that it is not a good idea however, as I mentioned before, one moon rock in at the beginning means less room for a super cell to be tossed in during the last 20 seconds.
darkChozo
06-01-2009, 00:51
SCORED: A GAME PIECE is SCORED when it is fully supported by the TRAILER or other GAME PIECES that have been SCORED.
Technically speaking, from this definition, you could make it so it was impossible to score without getting a cell stuck on one of the outer bars by placing some sort of blocking mechanism at the bottom of your trailer. Because any cells going into the trailer are going to hit the bottom, placing something there will mean that they are supported partially by the robot, and thus are not scored. In turn, any cells stacked on top of them wouldn't be counted, as they are being supported by something other than the trailer and scored cells.
That being said, the GDC seems to be severely limiting what the robot can do outside of its boundaries, and it seems to me that any plausible method of descoring or blocking will probably be made pretty explicitly illegal when the Q&A. It would make sense, considering that most of the ways of blocking and descoring would be reasonably quick and easy, and would mean that a trailer is essential closed to scoring, thus providing an immense advantage and a more boring game.
That being said, the GDC seems to be severely limiting what the robot can do outside of its boundaries, and it seems to me that any plausible method of descoring or blocking will probably be made pretty explicitly illegal when the Q&A. It would make sense, considering that most of the ways of blocking and descoring would be reasonably quick and easy, and would mean that a trailer is essential closed to scoring, thus providing an immense advantage and a more boring game.
I'm not the most familiar person on the board with the rules, but if you can manage to touch only the balls, then I would think you can descore an ally's trailer. It seems logistically impossible/impractical to descore yourself, though I suppose if all your robot did was descore, you could sit in one place and constantly pick out moon rocks, while asking for the occasional push from an ally. I.E. Your robot was simply a 10'' block with an arm reaching to your trailer, no propulsion and nothing but the descoring device. I don't recall there being a rule saying you need to have the ability to move, and in some ways, cutting a alliance's scoring potential down to 2/3rds could be a significant advantage.
I don't recall there being a rule saying you need to have the ability to move, and in some ways, cutting a alliance's scoring potential down to 2/3rds could be a significant advantage.Definition of a robot includes a mobility system. This is the first year for such a requirement. (Seciton 8.2) Also, if you can't move (or won't), there is an opposing Payload Specialist right behind you.
Definition of a robot includes a mobility system. This is the first year for such a requirement. (Seciton 8.2) Also, if you can't move (or won't), there is an opposing Payload Specialist right behind you.
Do you know if there is a speed requirement? If not, then I'm sure it would be possible for a rig letting you move around slowly without taking up much room, and the point of having a self-descorer would be to counteract the effect of that Payload Specialist, if I can make an arm that takes out my balls every second, I would think that I can take more balls out of my trailer, than any but the most spot on accurate payload specialist can put in my trailer. Also, they would be focused on me, meaning that the other team has effectively one Specialist for both of my Ally's. I'm not going to advocate this strategy however, just thinking that it is feasible, if you don't mind being a spoil sport.
Do you know if there is a speed requirement? If not, then I'm sure it would be possible for a rig letting you move around slowly without taking up much room, and the point of having a self-descorer would be to counteract the effect of that Payload Specialist, if I can make an arm that takes out my balls every second, I would think that I can take more balls out of my trailer, than any but the most spot on accurate payload specialist can put in my trailer. Also, they would be focused on me, meaning that the other team has effectively one Specialist for both of my Ally's. I'm not going to advocate this strategy however, just thinking that it is feasible, if you don't mind being a spoil sport.I didn't see a requirement for a given speed, or a requirement that it work (though I'm sure your partners will thank you for not being a relatively sitting duck).
Well that IS an interesting strategy. There IS precedent for an FRC bot to lack a mobility system (see 2007, and the sitting ramp-bot, sorry dont recall a team number but there WAS a pic on CD)
You might even be able to build a hopper with simple shooter that your descorer dumps the balls into to be able to use them.
IF you could make your descoring mech VERY functional, it might work.
pfreivald
06-01-2009, 10:07
Maybe I'm just not that creative, but I don't see how it is possible to extend any kind of cap over the trailer, even half way.
A. You can't extend outside your footprint.
B. The Trailer can't be tipped.
C. The Trailer has to be attached on the outside (convex or flat) of your robot, with a 10" tongue, in a way that the tongue will not touch your bumber while driving...
I suppose that a very short robot might be able to extend backwards to some degree, but a 10" tongue + half the length of the trailer actually seems to be *impossible* to me.
Am I missing something really key here?
Patrick
Kevin Sevcik
06-01-2009, 10:56
But as soon as you start restricting its motion from the inside, I'd call that some form of attaching to.
Realistically, I think this will end up in Q&A very quickly. I would expect that the answer would be something to the effect of "As long as no rules on contact outside the bumper zone are violated, it's fine."
Which then means that all one robot has to do to get you in trouble is tangle you up. If it's done enough, you have to modify your design.
Firstly, vaguely restricting the motion of an object isn't "attaching" to it. Apply that definition to robots, and pinning a robot would suddenly count as attaching to it. It's more on the lines of entanglement, which is judged case-by-case, and you have to actually end up caught up with the trailer.
Secondly, if the GDC restricts this by the contact outside the bumper zone rule, it simply makes it slightly more tricky. Remember that you're descoring on a trailer attached to one of your partners. They have a vested interest in not screwing you up. Also remember that a robot can not be forced into a penalty by an opposing robot. If an opponent is trying to stop you from descoring and this causes you to violate a rule, you shouldn't be penalized.
Maybe I'm just not that creative, but I don't see how it is possible to extend any kind of cap over the trailer, even half way.
A. You can't extend outside your footprint.
True!
B. The Trailer can't be tipped.
True!
C. The Trailer has to be attached on the outside (convex or flat) of your robot, with a 10" tongue, in a way that the tongue will not touch your bumber while driving...
True!
I suppose that a very short robot
Not necessarily!
might be able to extend backwards to some degree, but a 10" tongue + half the length of the trailer actually seems to be *impossible* to me.
Am I missing something really key here?
Yep! Here's an idea: try drawing the footprint within which you have to work (since that is your limitation), then include the portion of the trailer that you'd like to defend, then see if you can design a robot around what remains.
It's certainly possible. The only questions I have is;
1) Will FIRST allow a bot to goaltend in this way, and
2) Is incidental contact with the PVC bars of your own trailer (as in, not grappling or attaching to or climbing on, just occasionally touching or bouncing off with part of your robot) allowed?
I have to imagine #2 is going to be allowed, because there are going to be plenty of dumpers that engage in incidental contact when they pass balls into the opposing trailers. The real question is #1, because that's a conceptual question of how GDC wants this game to be played.
Also, where is everyone getting a 10" tongue from? Our mech team built one with a 14" trailer swearing it is correct from the drawings. Did they misread something?
Eaglepilot52
06-01-2009, 19:56
An idea my team had that was initially a joke (and still kinda is) was the idea of camoflage. What the concept is is that the robot is built to look exactly like the trailer. That way, the other teams would not know the trailer from the robot. But what would be needed to fool the other teams is having multiple trailer/robots. Having one, you would still be able to distinguish the robot from the trailer.
This could turn out to be a good idea, mabye not.
My team is still in the designing stage.
commodoredl
06-01-2009, 21:43
Actually that thought gives me an idea.
Looking through the manual, there are no rules against making your robot look like a field element.
I'm not thinking about the trailer though. I'm thinking about the foam cylinders on top marking alliances. Several teams, my own included, plan on using the camera to track and target other teams by their alliance indicators. Any teams who build their own dummy indicators would likely be able to fool most robots and mess with their targeting.
It would be very unGP to do something like this still. I will probably ask this in the Q&A because I wouldn't want to see teams doing something like this.
Daniel_LaFleur
06-01-2009, 22:14
Actually that thought gives me an idea.
Looking through the manual, there are no rules against making your robot look like a field element.
I'm not thinking about the trailer though. I'm thinking about the foam cylinders on top marking alliances. Several teams, my own included, plan on using the camera to track and target other teams by their alliance indicators. Any teams who build their own dummy indicators would likely be able to fool most robots and mess with their targeting.
It would be very unGP to do something like this still. I will probably ask this in the Q&A because I wouldn't want to see teams doing something like this.
I believe that <R2> makes that illegal
ROBOT parts shall not be made from hazardous materials, be unsafe, or cause an unsafe condition. Items specifically PROHIBITED from use on the ROBOT include:
A.
Shields, curtains, or any other devices or materials designed or used to obstruct or limit the vision of any PILOTS and/or COMMANDERS and/or interfere with their ability to safely control their ROBOT
B.
Speakers, sirens, air horns, or other audio devices that generate sound at a level sufficient to be a distraction or hindrance affecting the outcome of a MATCH
C.
Any devices or decorations specifically intended to jam or interfere with the remote sensing capabilities (including vision systems, acoustic range finders, sonars, infra-red proximity detectors, etc.) of another robot (i.e. changing ROBOT color to confuse opponent’s vision system)
D.
Lasers of any type
E.
Flammable gasses
F.
Any devices intended to produce flames or pyrotechnics
G.
Materials that off-gas noxious or toxic gasses
H.
Materials that produce hazardous inhalable particles
I.
Caustic chemicals
J.
Hydraulic fluids or hydraulic components
Teams should provide MSD Sheets for any materials they use that might be considered questionable during ROBOT inspection.
commodoredl
06-01-2009, 22:16
Ah, you definitely got me there. :o
Back to reading the manual!
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