Blocking 2 ball autons

[Greg Needel]

I think that we are all excited to see the 2 ball autonomous modes play out at the championship, but I want to look at the next stage in evolution of how to prevent these.

Given the assumption that both alliances have auton shooters, but one alliance has a robot who can (with some accuracy) do a 2 ball autonomous. It would seem reasonable to try and block this second ball. Not only is it 10 pts but it is also the tower strength implication of starting at 8 vs 7.

So now the question is how to do it.

All of the 2 ball autons I have seen use the low bar, grab the farthest ball off the center line after dropping their preload. It seems to me that the best way to disrupt the 2 ball is to beat them to the ball. This can either be through intaking it yourself or by just knocking it out of the way. All of this sounds easy, but the robot orientation is strange because of the secret passage and you have the same restrictions of not being able to cross the center line.


What do you all think, is it possible and is it worth the risk?

[BenHildy]

I believe a viable strategy to block this is, as you said, simply prevent the first ball from being intaked. One could do this by, theoretically, having their intake disrupt the other team's or have a mechanism that flips out and kicks the ball out from underneath the intake before it enters the other robot. Perhaps a "simple" piston?

EDIT: Pistons are never simple

[evanperryg]

Originally Posted by Greg Needel

All of the 2 ball autons I have seen use the low bar, grab the farthest ball off the center line after dropping their preload. It seems to me that the best way to disrupt the 2 ball is to beat them to the ball. This can either be through intaking it yourself or by just knocking it out of the way. All of this sounds easy, but the robot orientation is strange because of the secret passage and you have the same restrictions of not being able to cross the center line.

I would like to introduce the "no twoball boogaloo:"
You start at the opposite side of the field from your low bar, facing towards the opposite wall. Then, drive down the center line knocking all the boulders out of position. Then, collect the last one, drive under your low bar and shoot a high goal. #einsteinstrats

[Eric Scheuing]

Originally Posted by evanperryg

You start at the opposite side of the field from your low bar, facing towards the opposite wall. Then, drive down the center line knocking all the boulders out of position. Then, collect the last one, drive under your low bar and shoot a high goal. #einsteinstrats

This is pretty much what I was envisioning when I saw the 2-ball auto go. You just have to be careful not to cross that center line!

[willpflem]

It seems to me that doing this, and therefore starting in front of the secret passage, would prevent you from running a profitable auto yourself (minimum of a cross). In my opinion any winning alliance will have an auto for each one of its alliance members. So the question to me boils down to, 'Is blocking their 10 points more profitable than gain 10 of your own?'

[BenHildy]

Originally Posted by Eric Scheuing

This is pretty much what I was envisioning when I saw the 2-ball auto go. You just have to be careful not to cross that center line!

Very much so. I've seen far too many penalties given to teams because of crossing the centerline in auto. It's sad, really. I sometimes feel imprisoned by the inability to cross that tape in auto. But yet again, it's still better than last year! This year we just have to get creative for defensive autos!

[Donut]

Have your 3rd robot start with a ball in its intake lined up directly with the boulder the 2 Ball opponent would grab. Reverse intake at high speed, hitting the ball on the center line and hopefully knocking it out of position enough that the 2 Ball robot fails to acquire either ball. Alternatively if the ball does not move far you have now placed two balls very close together and the autonomous 2 Ball robot runs the risk of possessing two balls simultaneously while trying to acquire the center ball. If this occurs the 2 Ball robot will incur both a G38 and G41 foul for crossing the defense with 2 boulders, at worst cancelling out the extra goal with the 10 point plus tower strength increase penalties (this assumes the robot somehow scores despite 2 balls in an intake not designed for it).

You run no risk of penalties for crossing the midline or contact with this strategy. You sacrifice scoring a ball yourself, but for a low goal or defensive third pick defending a 10 point goal is a net positive versus 5 or no points yourself.

[CTbiker105]

Possible? Yes. Worth the risk? Probably not. While 2-ball autos generally risk violating only the first portion of G13, "During AUTO, ROBOTS may not enter the volume above the MIDLINE," attempting to block a ball from being grabbed by a 2-ball bot would run the risk of drawing two fouls, as G13 goes on to state:

"If contact is made with an opponent ROBOT beyond the MIDLINE (either direct contact or transitive contact through a BOULDER), an additional FOUL is assessed and the opponent ROBOT is immediately awarded the CROSSING of the closest DEFENSE from the point of contact."

Unless your blocking strategy is extremely precise and consistent, you're most likely going to hurt your own alliance by potentially drawing up to 2 fouls.

That being said, as a team with a 2-ball auto, I am interested to see what strategies, if any, teams employ to prevent it or mitigate its effects.

[Bob Steele]

In order to block the 2 ball auto, a team would have to give up on their own 1 ball auto in my opinion. Either grabbing the ball or intentionally hitting it would constitute possession.

If the only purpose in doing this is stopping the 2 ball auto... it would be a net gain of 0.

If a team could do this and still score a ball then it could be a net gain. This would mean you drop your ball... move to hit a ball or pick it up and then use it.
If you could stop a 2 ball and then do a 2 ball it would be amazing.

Unfortunately the only 2 ball autos that have been consistently shown are low bar versions. (Please correct me if I am wrong) So stopping a low bar 2 ball would have to come from a position on the field that can't easily do the two ball.


I am sure that some teams are working on fantastic auto routines and I look forward to seeing them in St. Louis. I also think that doing an anti-two ball auto is something that won't really help your team very much and that trying to do your own two ball auto is a better use of time. (Or solidifying a perfect 1 ball auto....)

IMHO
Feel free to disagree ....

Good luck on the field

[BenHildy]

Originally Posted by Donut

Have your 3rd robot start with a ball in its intake lined up directly with the boulder the 2 Ball opponent would grab. Reverse intake at high speed, hitting the ball on the center line and hopefully knocking it out of position enough that the 2 Ball robot fails to acquire either ball. Alternatively if the ball does not move far you have now placed two balls very close together and the autonomous 2 Ball robot runs the risk of possessing two balls simultaneously while trying to acquire the center ball. If this occurs the 2 Ball robot will incur both a G38 and G41 foul for crossing the defense with 2 boulders, at worst cancelling out the extra goal with the 10 point plus tower strength increase penalties (this assumes the robot somehow scores despite 2 balls in an intake not designed for it).

You run no risk of penalties for crossing the midline or contact with this strategy. You sacrifice scoring a ball yourself, but for a low goal or defensive third pick defending a 10 point goal is a net positive versus 5 or no points yourself.

I like this! However you do run the risk of having the robot intake both balls and being charged for forcing a penalty on another team. Also, if the balls collide, the the robot, however unlikely, may still pick up the ball launched at their original target. However, both of these issues are quite minor and unlikely. This solution is innovative and certainly would be entertaining to witness! I hope we do!

[g_sawchuk]

I would confidently say that it is definitely beneficial to try and counter a 2-boulder autonomous with a "steal". The plausibility is definitely present. You need to intake a ball in the time it takes them to:

A. Deposit their pre-load.
B. Intake the ball.

Without a doubt, even with a slightly less efficient robot, you could beat them to the boulder.

Having now confirmed that the strategy is plausible, we want to look at the value of stealing the ball. Assuming that you plan on shooting your boulder too, and you take a boulder, we're looking at the following scores (under the assumption that no other members of the alliance do any scoring tasks).
We will call our robot, the "stealer", the BLUE alliance, and the two-boulder-autonomous robot the RED alliance.

BLUE: 30
RED: 30

Stealing their targeted boulder effectively accomplishes the following:

A. Evens the scores.
B. You get a boulder out of the neutral zone, forcing it onto their side, making the boulder more accessible, as opposed to being way at the other side of the field after they have scored them.

Now, let's assume that the BLUE alliance robot is now only capable of intaking, and will only steal the boulder, and not breach or score the boulder. We would now see the following scores appear.

BLUE: 0
RED: 20

The margin is now greater (20 points), but they have only been able to minimize the margin. The BLUE alliance has benefited themselves by:

A. Reducing the score margin by 10 points.
B. Reduced the number of strength that their castle has lost in autonomous.
C. Gaining possession of one of the neutral zone boulders, limiting how many "easy cycles" the other alliance can complete by grabbing the boulders from the neutral passage, typically shortening their cycles.

From this, we can evidently see that even the simplest ball steal is quite valuable, and, even if it isn't a game-changer, it can still minimize the score margin.

[JesseK]

Originally Posted by evanperryg

I would like to introduce the "no twoball boogaloo:"
You start at the opposite side of the field from your low bar, facing towards the opposite wall. Then, drive down the center line knocking all the boulders out of position. Then, collect the last one, drive under your low bar and shoot a high goal. #einsteinstrats

Interesting idea for auton, but consider what it does to teleop.

There is no way to push a ball out of the way in auton without pushing it towards the outer works that the opponents are consistently crossing. This means that in teleop, if those balls are near those outer works they are effectively the opposing alliance's balls. At that point, for you to retrieve them you run the risk of contacting the opponent when they're in the outer works.

This is why defense bots at high levels need a great intake - they need to steal the balls from the midzone first so they don't plow them the wrong direction as they move across for defense.

[jspatz1]

Originally Posted by Donut

Have your 3rd robot start with a ball in its intake lined up directly with the boulder the 2 Ball opponent would grab. Reverse intake at high speed, hitting the ball on the center line and hopefully knocking it out of position enough that the 2 Ball robot fails to acquire either ball..

"G13 During AUTO, ROBOTS may not enter the volume above the MIDLINE.
Violation: FOUL. If contact is made with an opponent ROBOT beyond the MIDLINE (either direct
contact or transitive contact through a BOULDER), an additional FOUL is assessed and the
opponent ROBOT is immediately awarded the CROSSING of the closest DEFENSE from the point
of contact."

[Abhishek R]

Well, it's possible that you start with no ball, grab the ball the two-baller intends to take, then score that ball by crossing over the nearest defense and shooting. The risk you run in that case is "are you fast enough to grab the ball before the other team does?" Because if you don't get the ball, you won't score any balls in auto.

Furthermore, the teams most likely capable of this are probably doing their own two-ball or a one-ball over a tougher defense than the low bar, so their priorities may be elsewhere.

IMO the risk and comparative resources of the alliance necessary to pull this off will not make it worthwhile and we'll see more teams just focus on having all three of their robots drive over the defenses and score a ball. That doesn't mean it won't happen at all, I just don't see it being as big of a focal point as the can races last year.

[cjl2625]

Originally Posted by jspatz1

"G13 During AUTO, ROBOTS may not enter the volume above the MIDLINE.
Violation: FOUL. If contact is made with an opponent ROBOT beyond the MIDLINE (either direct
contact or transitive contact through a BOULDER), an additional FOUL is assessed and the
opponent ROBOT is immediately awarded the CROSSING of the closest DEFENSE from the point
of contact."

Is it still a foul if neither of the robots enter the volume of the midline? It looks to me that this rule states you get a double foul if you make transitive contact and are violating G13 by crossing the midline.

If I'm wrong, then I guess the foul would apply to whoever reaches the boulder second. In that case, the defending robot just needs to be confident that they're faster.

Edit: Actually, I might be misunderstanding what "transitive contact" means... I figured it means that if two robots are contacting the same ball, then they are effectively contacting each other