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  #16   Spotlight this post!  
Unread 01-02-2017, 23:29
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Re: Defensive Robots/Strategies?

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Originally Posted by Alex Cormier View Post
I am very excited to see how D will play out this year. Can't wait.
After your resounding success with defense last year, will you be going all out defense this year? If so, care to share ideas about defense?
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Unread 02-02-2017, 12:21
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Re: Defensive Robots/Strategies?

Remember that this field is mirrored rather than rotationally-symmetric. This means that the pinch points your defensive bot exploits also force your partners to go even further to place their gears. Sure, we could start getting into "but we'd go here, and you'd go there, but what if this and that.....". Yet there still remains a fundamental issue with playing zone defense that has no easy answer.

Just be sure your bot can deal with 120-150lbs of another robot crashing into you because you decided to get in their way while their robot was in 'ludicrous mode' .
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Unread 02-02-2017, 15:00
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Re: Defensive Robots/Strategies?

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Originally Posted by SMR Vault View Post
There are 2 core defensive strategies (from a general design standpoint) to consider based on the 2 volume constraints:
G11.There’s a 5-count on pins. ROBOTS may not pin an opponent’s ROBOT for more than five (5)
seconds. A ROBOT will be considered pinned until the ROBOTS have separated by at least six
(6) feet. The pinning ROBOT(s) must then wait for at least three (3) seconds before attempting to
pin the same ROBOT again. Pinning is transitory through other objects. If the pinned ROBOT
chases the pinning ROBOT upon retreat, the pinning ROBOT will not be penalized, and the pin
will be considered complete.
A question around pinning vs contact. G11 defines pinning this way:

"There is no FIRST® Robotics Competition specific definition of pin, so a general definition applies; “to prevent or stop something from moving.” As a result, contact is not required for pinning to occur. For example, a ROBOT parked right behind an opponent that is between dividers could be considered pinning because the dividers and the parked ROBOT prevent the opponent from moving."

So would contacting a robot for a period of longer that a 5 count be allowed assuming both robots were moving? Such as in the case of continued bumping or pushing?
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Unread 02-02-2017, 15:13
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Re: Defensive Robots/Strategies?

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Originally Posted by bmammen View Post
[size="3"]So would contacting a robot for a period of longer that a 5 count be allowed assuming both robots were moving? Such as in the case of continued bumping or pushing?
First off, this is a hypothetical situation, therefore is dependent on the situation and the referees during the match.

But imagine this scenario: Robot A is moving towards some point on the field to score points. Robot B wants to play defense on them, and so Robot B drives headlong into Robot A to prevent them from scoring. Both robots are in an open area, pushing head to head and neither are moving for over 5 seconds. This is typically not considered a pin. While neither robot is moving, Robot A could, at any time, throw it in reverse and try an alternate route. Robot B is preventing Robot A from getting to their destination via the most direct path. They are not preventing them from moving at all.

Now imagine this: Robot A has just scored, has one end against a wall or some other obstacle, and wants to drive back tot he other end of the field to reload whatever scoring piece. Robot B wants to play defense. Robot B does this by driving headlong into Robot A, driving it into the wall. Neither robot is moving for over 5 seconds. This would typically be considered a pin. Robot B is preventing Robot A from moving whatsoever and would be in violation of G11.

While that doesn't directly answer your question, you should be able to draw the correct conclusion form that.
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Last edited by Cothron Theiss : 02-02-2017 at 20:14.
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Unread 02-02-2017, 19:14
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Re: Defensive Robots/Strategies?

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Originally Posted by scott.smith View Post
After your resounding success with defense last year, will you be going all out defense this year? If so, care to share ideas about defense?
We'll see... we are in the process of making a teaser video of this years progress so far. Stay tuned.
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Unread 02-02-2017, 19:50
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Re: Defensive Robots/Strategies?

Our team saw the defensive strategy in this game as being similar to Aerial Assist. Both had fairly open fields, and pinning for longer than usual was allowed. What worked very well for us was going across the field at full speed on a 6-CIM drive and hitting opposing robots, then shoving them. It is unclear as to whether this is allowed this year, but a hit to a corner would definitely throw off a team's aim. A hit while placing a gear on the peg could also interfere, as could blocking chokepoints. What I'm trying to say is that we think that harassing opposing robots is better than constantly trying to defend. One idea we also had, which is of questionable legality, is to ram the opposing alliance's airship while a pilot is lifting a gear. If this is allowed, and depending on the construction of the airships, this could cause a pilot to drop a gear.
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Unread 02-02-2017, 20:12
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Re: Defensive Robots/Strategies?

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Originally Posted by qscgy View Post
One idea we also had, which is of questionable legality, is to ram the opposing alliance's airship while a pilot is lifting a gear. If this is allowed, and depending on the construction of the airships, this could cause a pilot to drop a gear.
Disregarding the legality aspect of this strategy, I just don't think that this would be reasonable given the fact that FIRST wouldn't put a major permanent structure on the field without it being extremely secure and well built. It would have to be built specifically to withstand the impact of a robot. It would seem to me that if a robot would be able to shake the entirety of the airship with sufficient force to distract a human player that the airship is not robustly built enough.

I think that this really isn't the best possible defensive strategy. Your better bet would be to go after the robot while its trying to place the gear. Even if their gear just drops into a slot that the drivers pick up from, which is by far the simplest option that there is, then you can still hamper the teams ability to proper place the gear on the peg.
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Unread 02-02-2017, 20:51
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Re: Defensive Robots/Strategies?

This kind of thread is among my favorite. So much good information, point and counter-point, and I most often defer to the teams with the most experience in planning and executing this aspect of the game.

This year however has two very striking differences, and only one mentioned here so far. The fact that this years field is mirrored, meaning that instead of counter current flow, most team's modeled and practiced cycle times will likely mostly occupy the same space, leading to offense basically having a built in defense - or the stronger bully wins. This also means that defensive skirmishes have to be well designed and executed or you are interfering with the cycle time of both you and your opposing alliance. Couple that with more than one skirmish and you could shut down the whole field, especially in elims with 4 total gear runners.

The second difference is the possibility for hundreds of game pieces littering the field. Not all robot-robot interaction is going to be the classical, and by now predictable, bumper-to-bumper, my drive train is better than your drive train pushing around...there's going to be balls (and maybe gears) stuck between bots in what may be a completely untested fashion. Remember the old trick, now outlawed, of putting solid noodles on bottom and hollow on top in order to jack up an opponents bot to get the upper hand. I predict many robots will be getting jacked up on fuel, and I'm not talking about Red Bull.

This years game is sure to be a crowd pleaser, and I further predict as the competition weeks progress, when offensive strategies progress so too will defensive strategies and we may not see the steep curve in high scores that we did last, especially considering the diminishing returns of gear running.
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Unread 02-02-2017, 23:03
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Re: Defensive Robots/Strategies?

What about a team who builds a very small drivetrain then just defends shots.
Ex. A team chooses the 36x40x24 volume and builds a 29x18x24 chassis. They can now extend approx 15 inch from their frame. They could extend a 15 inch shield or sorts to hover over top the opponent shooter. Like team 1405's robot in stronghold.
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Unread 02-02-2017, 23:51
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Re: Defensive Robots/Strategies?

Quote:
Originally Posted by ns3517 View Post
What about a team who builds a very small drivetrain then just defends shots.
Ex. A team chooses the 36x40x24 volume and builds a 29x18x24 chassis. They can now extend approx 15 inch from their frame. They could extend a 15 inch shield or sorts to hover over top the opponent shooter. Like team 1405's robot in stronghold.
My team (who also cheesecake a blocker of our own last year) considered this idea early on in the season. We didn't go with it since we thought that we would be far better off with a larger drivebase which would help us in pushing matches. IMO the most effective defense this year will be ramming, pushing, pinning, and misaligning opponents with your drivetrain, thanks to the lack of safe zones (and the huge point value discrepancy between gears and fuel). I believe that teams who want to play defense should invest far more into their drivetrain than a blocker.
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Unread 03-02-2017, 09:40
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Re: Defensive Robots/Strategies?

Quote:
Originally Posted by ns3517 View Post
What about a team who builds a very small drivetrain then just defends shots.
Ex. A team chooses the 36x40x24 volume and builds a 29x18x24 chassis. They can now extend approx 15 inch from their frame. They could extend a 15 inch shield or sorts to hover over top the opponent shooter. Like team 1405's robot in stronghold.
So long as the robot being blocked has an exterior surface at the maximum height (24") this would not work because you cannot rotate your blocker up above 24" to get it above their shooter.
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Unread 03-02-2017, 09:49
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Re: Defensive Robots/Strategies?

One thing that might happen is robots is fuel getting stuck in gear mechanisms, specifically passive ones, incapacitating them for that match. In theory, intentionally doing so is almost definitely illegal via G08.

"Don’t tear others down to lift yourself up. Strategies aimed at the destruction or inhibition of ROBOTS via attachment, damage, tipping, entanglements, or deliberately putting a GEAR on an opponent’s ROBOT are not allowed."

Violation: FOUL and YELLOW CARD. If harm or incapacitation occurs as a result of the strategy, RED CARD.

There are some hypothetical scenarios where this could be a problem however. If robot A pushes robot B into a hopper, causing one of the 50 balls to get stuck in, and incapacitate one of the mechanisms on robot B, what happens? How do you judge intent of an otherwise acceptable defensive action? The strategies "aimed at" wording makes it seem like intent would need to be present to draw a foul, but wouldn't it therefore be a result of strategy and always draw a red card? Obviously it is the head refs discretion, but is there any direction you think these rulings would normally go?
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Unread 03-02-2017, 10:26
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Re: Defensive Robots/Strategies?

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Originally Posted by SpaceBiz View Post
One thing that might happen is robots is fuel getting stuck in gear mechanisms, specifically passive ones, incapacitating them for that match. In theory, intentionally doing so is almost definitely illegal via G08.

"Don’t tear others down to lift yourself up. Strategies aimed at the destruction or inhibition of ROBOTS via attachment, damage, tipping, entanglements, or deliberately putting a GEAR on an opponent’s ROBOT are not allowed."

Violation: FOUL and YELLOW CARD. If harm or incapacitation occurs as a result of the strategy, RED CARD.

There are some hypothetical scenarios where this could be a problem however. If robot A pushes robot B into a hopper, causing one of the 50 balls to get stuck in, and incapacitate one of the mechanisms on robot B, what happens? How do you judge intent of an otherwise acceptable defensive action? The strategies "aimed at" wording makes it seem like intent would need to be present to draw a foul, but wouldn't it therefore be a result of strategy and always draw a red card? Obviously it is the head refs discretion, but is there any direction you think these rulings would normally go?
Balls getting stuck will absolutely be a problem for most teams, especially the errant ball that pops up when plowing into them near the feeder station. It was among the reasons I forced our feeder team to pivot last night and re-evaluate most decisions and assumptions about the feeder last night. In the end our tests showed that our mechanism could be crazy-simple and still deal with this exact problem.
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