How To Deal With a Defensive Robot

VEX Robotics Competition Discussion VRC > In The Zone (17/18)
#1

Hey all,

There’s been some discussion about defense being too strong in VEX In The Zone, but I couldn’t disagree more. Before, I only had hypothetical strategies in order to deal with defense, but after our tournament yesterday, I’m glad to say that all of those strategies, and more, can allow a coordinated alliance, or simply a robot with a strong and fast drive, to make a dedicated defensive robot impractical.

As for coordination, this section of this match is a great example.

Also, make sure to use the starting bar for your own protection. For a defensive robot, it is basically suicide to ram into a robot that is near the starting bar. You have to assume they are or will be touching it soon.

As for having a fast/strong drive, this section of our first qualification match is a great example.

Notice how I run around them and am fast enough and have enough acceleration in order to get around the stationary goal and a pileup of objects before they can react. Moving these objects away probably would have been worthwhile, though. I did not intend to push them over the starting bar, but if that happens, it’s a pretty clear case of trying to get through, not trying to cause a DQ. Therefore, we would not have been DQ’d for that. And we would have scored that mobile goal immediately, had it not gotten st uck weirdly. (We did score it later.)

Note that this is not to hate on this particular defensive robot. They did a quick build in order to have something to work with, and they did very well considering. But, it’s not viable in the long term, and I don’t think they ever claimed it was. Moreover, as the season progresses, the proportion of points that come from mobile goals will diminish compared to cones. Therefore, losing a robot to defend the zones will be even less practical, even without great coordination.

Our drive is 8 motors 2.4:1 on 4-inch wheels, by the way.

#2

There was a lot of defensive play by a number of robots yesterday. Very fun to watch. It will be interesting to see how defensive strategies develop more as the season progresses.

#3

Not saying that pure defense will be viable in the long term either, but don’t you think the red robot without the mogo stack in the first clip was pinning for pretty clearly more than 5 sec?

#4

What we did against 2 defense/Mogo only robots is us and our alliance partners both grabbed a mogo in auton, you should be able to beat the defense robots to the first 2 mogos if they have blocking autons. We scored them only with our preloads on, we grabbed the next 2 as fast as possible. At that moment we had 34 pts, not including auton and bonuses, and they had 50, all we needed to do was stack 8 net cones to match their score because the cones still count when they are on mogo in your robot. This was fairly easy to do and we won by a large margin. If you are an internal robot defense is not some magical strategy that breaks the game. Its just annoying and requires a different approach to the match. Also, if they want to play defense on you while you have a stack let them, if it tips they are gonna get DQ’d and every cone you add makes it more likely for the stack to fall over.

#5

What @Zach929Y doesn’t realize is that my defense bot optimized is too OP for the world to see. (I might revive it one day)

#6

I’m not sure about that. We played some defense yesterday, too. Unless you can grab the mobile goal in two seconds flat, you are still somewhat susceptible to blocking autonomous routines. That being said, we did use our right to place last as red in the Finals in order to have 2114Z’s autonomous, which goes for mobile goals, not be interfered with by the blocking robot. Our stationary goal autonomous is pretty hard to prevent, though.

#7

I suspect a lot depends on what the local refs are willing to allow and from what part of the game manual they are interested in quoting. I think some refs are interpreting rules to greatly reduce aggressive defensive action on the field and to somewhat reduce fist fights in the stands. I’ve always been worried that things could get very ugly with this game.

#8

They should have the actual student participants ref matches. Good teams know the rules inside and out.

#9

A year or two ago there was a fight after how the state comp went

#10

I am pretty sure about that, if you have a competitive internal you will be fast enough. You have to travel less distance and you have no cones in the way. Unless you have a crazy fast chassis, which is not optimal because the loss of torque to push, you should always beat the team to the mobile goal.

#11

For us, we were planning on making a 6 motor drive because we started to notice a lot of teams immediately go to push our robot around or stay in our five point zone during our last competition as most of the time my team was the only one able to score cones and/or mobile goals during qualifications, and during the first competition there were a couple matches where a robot would stay in our five point zone a lot of the time. Hoping this helps shuts down the defense that could be used on us

#12

This is very true. Our team was low on time, so we threw together a mogo/defense bot. After a match where we played defense in their 5 pt zone, head ref said we’d be DQ’d if we did it again. I showed him rules, forum posts, etc showing that it was legal, yet he blew me off and said we couldn’t do it. He believed we weren’t even allowed to touch their 5 pt zone.

#13

That seems like it has less to do with misquoting rules and more to do with blatantly making up rules.

2114r did not appear (I wasn’t there, just looking at the video) to be trying to escape from that area, and thus would not be pinned by 127x. If they had been trying to escape, then it would likely have been a pin.

#14

What I’d do if there was a defensive robot would be to use defensive strategies on their partner.

#15

They literally took their fingers off the joysticks while yelling “pinning.” So there was no attempt to escape. There was a clear avenue of escape, but when they did move, they kept pushing back to prevent 2114Z from dropping the stack in.

#16

I used to think that defense was going to be a big problem in In the Zone, but I don’t think that they will be a huge issue going forward. First of all, in any decently competitive match, mobile goals make up less than half of the score of an alliance. In that case, a robot that defends against scoring mobile goals is pretty useless, given that it represents half the scoring potential of an alliance being used to reduce the opposing alliance’s scoring potential by half. Of course, this is not totally true, because most competitive teams in the world can score over 100 points alone, and the highest match score in the world is 145 (not 200) because mobile goals are so much easier to score. However, defensive robots are never 100% efficient, especially given that so many teams are electing to score mobile goals in autonomous.

Assuming that an alliance is able to score a single mobile goal (in the 20 point zone) before a defensive robot gets into position, that alliance’s score cannot be reduced by more than 40 points (10pt mogo x 3 +2 * highstack = 40 or 10pt mogo x 2 + 5 point mogo x1 + 3 * highstack = 40). That is slightly less than half an average alliance score in a competitive match However, it is to be considered that this is the best case for the defensive robot, that defensive robot will be unable to contribute to winning autonomous and or gaining high stacks that are included in this calculation, and that as @Aponthis showed above, it is relatively easy to circumvent defensive robots.

TlDR: cones make up more than half of points in competitive matches and defensive robots aren’t 100% effective; They are not at all beneficial.

#17

@sazrocks @Aponthis I wasn’t there either, but it did look like there was at least a good 1-2 seconds of 127X actively pushing them against the starting bar. Even if y’all may not have been pinning for the whole 8-10 seconds, a pin is only officially over when the robots are separated by one tile length. I get that G12 states that refs must err on the side of the offensive robot, but SG4 pretty clearly says that the “pinning” robot must move away, not the “pinned” one.

Anyways, grats on the tournament win, Aponthis. It seems like you all were able to put the 8 motor drive to great use.

#18

Not that it really matters, since it was far from match-affecting, but the pinning count does not occur or continue unless the robot is actively trying to get away. Which, they didn’t seem to be, to me. They were trying to stay in and keep defending, and had an avenue to strafe away pretty easily.

I thought that there was still the rule that an expanded defensive robot could be pinned, which was the case in Skyrise, then was not in NbN and Starstruck, because it wouldn’t be possible in either, but I was mistaken.

Yeah, it will be four or six motors after our next tournament, but an eight-motor drive is always really fun. And it made Skills easy, even if I was a shmuck. We probably would have gotten 100+ driver if our mobile goal intake wasn’t prone to drop mobile goals (we got 92), but again, I’m a shmuck. :wink:

#19

@Aponthis Is that a passive claw? How well does it work?

#20

Defensive bots are pointless to the max. You can literally do everything a defensive bot does with the drive of your offensive bot.