[FTC]: Defense robots and competition

[team F.T.C 4240]

Hello I was wondering, why are there a ton of defense robots and not very many offence robots, why would teams try to stop other robots that are doing what the game is intended for? Also if you spend all of you time defending that means you are not scoring any points meaning hardly any chance of winning and hardly any ranking points. So that presents one more challenge for offence robots, to make the robot robust and most-likely geared down a bit, but I would like to hear your comments about the matter.

Thanks
~Derrick

[Chris is me]

If it's easier to prevent a point from being scored than it is to score it, it's good strategy, as a point denied is equal to a point earned. However, if you score 1 less point than your opponent got through you, then it's a losing strategy.

If it is dominant enough to be what's won multiple events, then it's obviously not, though. Maybe teams discovered that blocking robots, then securing the end game bonus would win more reliably than trying to sort out the batons? If so, more power to them.

[Andrew Schuetze]

From a design side of things, lack of time or limited fabrication abilities means that an elaborate scoring mechanism is often times not achievable while a simple drive-base with quickness and agility is almost always achievable. Just plain getting in the way may be all that some teams in certian circumstances is all that they can achieve and so defense is their only real option.

Not saying that I promote this line of reasoning.

[Andrew Remmers]

I personally have seen the majority of the matches played, from the competitions I have gone to have alot of defensive strategy especially in automode surprisingly. Faster robots would play defense by driving and disrupting the trailer positions causing the teams auto to miss the 5 preloads. Our robot specifically is a "defensive bot" as one would call it but we geared down so our autonomous mode would be very accurate not for playing defense. But the pushing power has come through for us in many occasions in the past and in this season. However future iterations of our robot will have a 1:1 ratio or something very close to 1:1 for reasons of a slightly faster robot and still an accurate autonomous.

[JesseK]

Competitive games are won by point differentials, not by point potentials.

For robots that can do 1 simple thing very well, this game is perfect for defense. This game already takes 1/3 of the field away and forces offensive scoring to go into the opponent's zone to be effective, so it's as if the GDC wanted high amounts of interaction with this game.

For the team I coached, the simple thing [will be] dumping batons in autonomous and [was] traversing the field in autonomous. It's an easy 20-25 points, and the kids were very glad to play heavy defense for the rest of the match after autonomous. The field is so cluttered that the only time we pinned another robot was when the comms cut out and the robot moved forward on its own. Simply being somewhere on the field has been good enough defense to shut down a baton offense in this game (so far anyways).

Once (if) the kids fix their drive train implementation before the next qualifier, pushing both opponent teams off of the bridge (pre-endgame) shouldn't be impossible either. The tactic probably wouldn't work at the Championships, but for qualifiers where alliances balance at the 1:00 mark, it's perfect.

Offense itself is fairly cornered into 2 or 3 good designs with this game. Even the mediocre designs last year (HotShot) could score decent points in the low goal. This year, at most the mediocre designs will score 5 batons for 5-10 points.

I advise that you get more power to your drive train and figure out how to get more traction. Then implement a good autonomous. There are ways to get better traction; if any team at the Championships last year paid attention to both fields, they would know what those ways are. Good Luck!

[Chris is me]

I feel it's worth noting that a defensive robot only needs to "gear down" its drivetrain to the point where the traction wheels slip on the foam when pushing against a wall. A lot of teams especially in non-FRC competitions gear down thinking more torque always means "more pushing power", but once you're limited by traction, you might as well stop since you'll be able to drive faster.

[team F.T.C 4240]

All good advice but i think there is a middle ground between them as in having a robust robot that can play defense or just to get the defense bots out of your way and having something that can score and not just wait until the end game.
Also think of you ranking points and the judges because my bet is that the judges wont conceder defense robots for the inspire award or anything that includes GP.

[JesseK]

All good advice but i think there is a middle ground between them as in having a robust robot that can play defense or just to get the defense bots out of your way and having something that can score and not just wait until the end game.
Also think of you ranking points and the judges because my bet is that the judges wont conceder defense robots for the inspire award or anything that includes GP.

Be careful in your assumptions about what the judges will or will not award based upon defensive robots and how "unGP" those robots are in your opinion. Additionally, RP's may be low, but the QP's often times make the RP's not matter if you're undefeated.

Indeed, there is a middle ground; it's why we lost the qualifier ;).

[JohnFogarty]

This is something i'm noticing in a lot of videos and quite frankly I'm quite annoyed with it. Designing a robot with a quick way of scoring and getting around the field, more complex isn't always better. Remembering things from last year I swear we had the most basic robot robot out there and it got the job done to the extent we got picked for the world winning alliance. The object is is following the KISS method. but I will say this 4WD will be very useful if you get stuck in a pushing battle with another team.

[team F.T.C 4240]

Be careful in your assumptions about what the judges will or will not award based upon defensive robots and how "unGP" those robots are in your opinion. Additionally, RP's may be low, but the QP's often times make the RP's not matter if you're undefeated.

Indeed, there is a middle ground; it's why we lost the qualifier ;).

When I typed my last message I was in a hurry and I don't think having a middle ground is why you lost, and you cant blame it all on the robot because everyone that has gone to a competition knows that there are alot of things that can and most likely will go wrong or something didn't work right or there could have been a lot of good robots but just because you lost doesn't mean that the middle ground is a bad choice because if you have an Only offence robot then you can get blocked easy = hardly any points and a Only defense robot might block good robots but wont score at all = NO points so how ever you look at it you cant JUST have a offence robot or JUST a defense robot and win (unless you have a good partner) there needs to be a middle ground and you need to have a good robust robot that can score well, and having good drivers really helps, that is what I consider the middle ground and you can't blame it if you lose.

[gblake]

... what the game is intended for ...
~DerrickHey Derrick - It looks like you started an interesting discussion that is headed in the right directions.

However, in your original post, I think you made a mistake. Your comment about "what the game is intended for" makes me want to swat something with a rolled up newspaper and shout "Bad mathematician".

Once the rules are published, the game is what it the rules say it is. No amount of opinions will change that one whit. The rules (and I mean the real rules, not the introductory material) determine the scores, and the scores determine the QP and RP.

In discussions that don't stray off into outrageously exotic scenarios, there is little to nothing else that enters into the situation.

If you want to put some sort of extra constraints on your ability to succeed, no one can stop you; but if/when you do that, you begin playing some personal variation of the FTC game, and not the real one. When/if that happens, teams who are playing the real game will have an advantage over yours.

Cooperate like crazy off the field, compete like crazy on the field.

An enthusiastic, helpful and effective team; carrying out a thoughtful and successful defensive strategy; should be able to make a perfectly fine impression on well trained judges and on the other competitors.

Blake

[Joachim]

Your comment [ ] makes me want to [ ] shout "Bad mathematician".

. . . . Once the rules are published, the game is what it the rules say it is. No amount of opinions will change that one whit. . . .

Blake

This is certainly the ideal. But actual competitions vary.

There is a real (meaning non-imaginary) bias, at some events at least, that favors playing offense and disfavors playing defense. At such events "Gracious Professionalism" sometimes tends to be thought of as a rule for how robots interact (even those on opposite alliances), not just for people.

Although the game ideally is only what the rules say it is, in reality it is played and judged in a larger political, social, and economic environment that sometimes disfavors defense. I suppose this is not unrelated to trends in kids' sports, like soccer without scorekeeping with trophies for all. I think teams with enough experience in FTC--and team members with experience competing in other youth-centered competitions--tend take this into account, and they are only being realistic to do so.

You don't need a large number of opinions to make a difference--one or two held by the head ref or by the FTC local affiliate partner is enough. Though they may all have good intentions, they're not all good mathematicians.

[gblake]

Though they may all have good intentions, they're not all good mathematicians.And that is a good reason to encourage the OP to 1) carry a newspaper to the competitions, and 2) argue against such misunderstandings instead of tolerating them or advocating that they are the "correct" interpretations.

I think you and I are in synch.

Blake

[normalmutant]

This game will favor good baton-scoring robots. Even if they can't score in teleop, they should be able score enough batons in end game to counter a defensive robot's balance score.

[team F.T.C 4240]

At the Maryland competition we had a defense robot on our alliance and the head ref yelled at us, telling us that.
"This is not the intent of the game, if you want to brake another robot there are competitions for that BUT this is not one of them, try scoring for once instead of preventing it".
So yes every competition has refs with other views of how the game should work but in our case the guy was 100% against defense robots that don't score so that was my experience from the Maryland competition.

[Andrew Remmers]

At the Maryland competition we had a defense robot on our alliance and the head ref yelled at us, telling us that.
"This is not the intent of the game, if you want to brake another robot there are competitions for that BUT this is not one of them, try scoring for once instead of preventing it".
So yes every competition has refs with other views of how the game should work but in our case the guy was 100% against defense robots that don't score so that was my experience from the Maryland competition.

I don't think that its the refs decision on weather a defensive robot strategy is the "intent" of the game. That certainly was not very professional of him. You could have probably talked to the FTA or the person running the competition.

I know as a volunteer refs have tended to be clueless this year for where I have volunteered at. They either didn't know the rules, refs didn't see extreme rule breaking and didn't penalize teams for it (our team lost in semi finals because of this), and the list goes on and on. But thats not the point, sometimes you just have to politely talk to the right person and get whatever situation is the problem worked out, I know from a personal experience volunteering that some refs don't even know how to score the game and missed something like 45 points that one alliance scored... I talked to the head ref and this mistake was fixed, It didn't change the outcome of the match but it certainly effected scouting information.

So weather your defensive or offensive, If a ref yells at you they really shouldn't be, YOU decided to build your robot the way you did for a certain reason. From a personal standpoint our teams robot once was pushing all the robots and some carts across the field in a defensive strategy and no one thought it was a "bad" thing as far as I know.


My $.02

Andrew

[Chris is me]

At the Maryland competition we had a defense robot on our alliance and the head ref yelled at us, telling us that.
"This is not the intent of the game, if you want to brake another robot there are competitions for that BUT this is not one of them, try scoring for once instead of preventing it".

If the robot was not clearly damaging the other (ie trying to tip it, trying to rip off an arm), that sounds like something completely uncalled for. There's no rule saying the refs should punish teams for playing legal defense, and being yelled at for a perfectly legal strategy is just wrong.

I'd pass it off as a new volunteer or something, but you said it was the Head Ref...

[team F.T.C 4240]

He was "yelling" most likely because it was loud and wanted to make shore we herd, but I think the reason he said it was because our alliance partner was ramming the other robots the whole time and not letting them score at all and was trying to make so they couldn't balance wile we scored, it wasn't all there flat though, there scoring mechanism broke or something so we asked them to play defense (but not that hard because we wanted ranking points) but the head ref knew what he was talking about and was knowledgeable about the game and you could tell because he made some really good calls. The Maryland refs where alot better this year.

[normalmutant]

I think the reason he said it was because our alliance partner was ramming the other robots the whole time and not letting them score at all and was trying to make so they couldn't balance wile we scored, it wasn't all there flat though, there scoring mechanism broke or something so we asked them to play defense (but not that hard because we wanted ranking points)...

Oh, okay. In that case, they still are allowed to play defense, but if you guys were winning by a lot, then it'd be more polite to give them a little chance.
Btw, for those teams out there who don't know this (I'm sure most of you guys do): ramming is not a good idea. You can hurt their robot, but you're more likely to hurt your own robot. It's best to just push.

[gblake]

At the Maryland competition we had a defense robot on our alliance and the head ref yelled at us, telling us that.
"This is not the intent of the game, if you want to brake another robot there are competitions for that BUT this is not one of them, try scoring for once instead of preventing it"....Depending on whether or not you were bashing into the other robot, or simply playing tight defense; I would encourage you to politely but firmly disagree with that ref, and to politely but firmly appeal to the head ref if you feel that the refs opinions/prejusdices result in any non-trivial disadvantages for your team.

I just read the post that says an ally was ramming an opponent - Ramming is not the same as pushing. - When I am ref'ing I definitely tell teams not to repeatedly back up and hit an opponent; and not to take aim from far away, and then charge into an opponent at high speed.

Some other games that involve physical contact (human-human) make pretty good analogies. If you are swatting basketballs out of the air and doing a legal amount of leaning on the opponent - That's legit. If you are fouling the opponent - that not legit.

Learning to advance persuasive arguments that correctly link facts to defend an assertion, can (should?) be one of the benefits of participating in STEM robotics competitions.

Blake

[Joachim]

When I am ref'ing I definitely tell teams not to repeatedly back up and hit an opponent; and not to take aim from far away, and then charge into an opponent at high speed. . . .

Some other games that involve physical contact (human-human) make pretty good analogies. . .

Learning to advance persuasive arguments that correctly link facts to defend an assertion, can (should?) be one of the benefits of participating in STEM robotics competitions.

Blake

The distinction between fouling and tough defense in basketball is notoriously subjective, but it might also be a very good analogy.

Repeatedly backing up and pushing (or "hitting") was the only effective defense played against the team I mentored last year. That was how the defending teams avoided being called for pinning--push (or "ram" if you want to call it that), back up a little then push (or "ram") again, as many as 6 or 7 times in 15-20 seconds, for example.

Unfortunately, our team also learned (from three seasons' experience) to do the same thing, did it twice in one match (with two pushes or "rams" in one set and three in another), and damaged another robot doing it. Result: the team was DQ'd for "excessive force", one hour after the match in question was over. There were no warnings or calls made during the match, nor immediately after when the damaged team complained.

I asked the head of all officials and judges, who gave us the DQ news, why the call was "excessive force" and not "intentional damage", since the second term was in the game manual, the first one not. (Presumably the "intent" of "intentional damage" must be judged by the referees on the field at the time, and not by a committee of all refs reviewing damage in the pits, as happened here.) At first he stood by his position that it was in the game manual, then shifted to say "excessive force" was in the referee manual. When I said "I don't think I've seen the referee manual" he said "you're not supposed to."

From a lowly team's point of view, the game is exactly what the head officials or the FTC affiliate partner of the competition say it is.

[Chris is me]

Unfortunately, our team also learned (from three seasons' experience) to do the same thing, did it twice in one match (with two pushes or "rams" in one set and three in another), and damaged another robot doing it. Result: the team was DQ'd for "excessive force", one hour after the match in question was over. There were no warnings or calls made during the match, nor immediately after when the damaged team complained.

I asked the head of all officials and judges, who gave us the DQ news, why the call was "excessive force" and not "intentional damage", since the second term was in the game manual, the first one not. (Presumably the "intent" of "intentional damage" must be judged by the referees on the field at the time, and not by a committee of all refs reviewing damage in the pits, as happened here.) At first he stood by his position that it was in the game manual, then shifted to say "excessive force" was in the referee manual. When I said "I don't think I've seen the referee manual" he said "you're not supposed to."

I don't have anything to say other than that's just ridiculous. A DQ an hour after a match, referencing a non-existent rule interpretation from a document teams can't read (and thus can't know whether or not they'll break said rule)?

Is this seriously the standard for FTC refereeing?

[Joachim]

Is this seriously the standard for FTC refereeing?



I don't think it's the standard at all, probably more of an aberration.

But it is an example of what has happened before.

I should add that I did write to Ken (Johnson) last season, in more detail than I gave here, not to appeal, but to give information in the hope that similar situations could be avoided in the future. His reply included a mention that the scenario our team experienced would be used (in some way not stated) as an example for training officials in the future.

[team F.T.C 4240]

[QUOTE=gblake;985926]Depending on whether or not you were bashing into the other robot, or simply playing tight defense; I would encourage you to politely but firmly disagree with that ref, and to politely but firmly appeal to the head ref if you feel that the refs opinions/prejusdices result in any non-trivial disadvantages for your team.

I just read the post that says an ally was ramming an opponent - Ramming is not the same as pushing. - When I am ref'ing I definitely tell teams not to repeatedly back up and hit an opponent; and not to take aim from far away, and then charge into an opponent at high speed.

Well you are right in the sense of not bashing into other robots at high speeds, but that is what our alliance was doing. We pushed the rolling goal to the other side and started to score and both apposing robots where trying to get batons out from the low and high dispensers. Our alliance partner was in the middle ramming one then the other making so they couldn't dispense so that is my guess why he (as in the head ref) said it, also he happened to be reffing our match so it wasn't like someone had to get him or anything. Also our partner showed up at the last minuet so we just said play defense so thats what they did and we really should have made it more clear what we meant by defense. I did agree with the ref then we had a rematch and it went well there on out.

[TRWSHSHLX]

There's a lot of ways to play defense in a match. Some are perfectly legal but some not so much. From last year's experience (Oregon's first qualifier is at the end of January so I haven't really see much actually matches this year), here are some things that might help to understand why teams play defense and whether it's legal or not:

Acceptable defense: (all from what I had witnessed in an actual match before and didn't get penalized)
1. Pushing
2. Pinning for 5 seconds and back away 18 in. (one carpet length would be perfect because it's definitely longer than 18 in, I am not sure if it's two feet or 18 in. but same principle apply)
3. Blocking (Blocking as in preventing one direction of movement of the oppose alliance's robot, not ALL direction)
Defense that will most likely get penalized:
1. excessive ramming (it's pretty obvious and that's the easiest way for judges to DQ you)
2. flipping oppose alliances' robot over (sometimes it's not intentional but the referees will most likely think so. So if a robot and your robot is pushing against each other and the opponent's robot is climbing up the front of your robot, you should back off because if they keep driving straight, the judges will probably think it's intentional)
3. Intentional Entanglement (Reaching / Grabbing other robots hands / parts etc...)
There are probably more things for both lists but that's all I remember for now.

Most teams play defense it's because it's simply easier. It takes way less effort to play defense than playing offense especially when you don't have an efficient scoring mechanism. However, I personally think that ramming and intentionally ramming and breaking other robots is extremely unGP because if the situation is reversed and your robot is the one that's being rammed into, it's not exactly a good feeling. However, good defense strategy should be encouraged to some extend because that's when the judges can differentiate how efficient the robot's drivetrain and scoring mechanisms are compare to other robots. In World's final last year, the Smoking Mirrors shoot all their preloads in merely few seconds (literaly... 2-3 secs) and I don't remember how many they actually made but that showed how efficient their robot was. And for the last 1 minute there was a lot of defense played by both sides but the alliance with better drivetrain and better scoring mechanism wins.

As for the referees, there's nothing you can really do about it after they make a call. So the best thing to do is ask the possible situations that might happen and ask them how they will call / interpret it before the match. Another way is to follow what other people do. If one team's robot played excessive defense and it was allowed then it's perfectly fine to replicate what they do because they didn't call it the first time. And the same principle applies for whatever judges DQed people for.

Defense should be avoided if possible, considering how efficient the scoring mechanism work. In qualifiers it's not a good thing because ranking points will be very low; however, in elimination rounds, the point differential is what matter after all.

Good luck to all the teams out there!
P.S. If I have time I will see if I can post Oregon's last year's state final and there were some excellent examples of defense and good referee calls.