Inbounding or Hoarding Balls

[Joe Johnson]

Paul,
3 balancing is worth 20pts*.

My read is that that is about right.

The task is hard but not TOO hard. The points are high but not TOO high.

What is it going to take to get 3 robots on that 88" bridge"

Assume robots fill the given space, with bumpers robots are roughly 44" by 34" give or take.

If enough teams go wide (34" up the bridge), then you have 6" hanging out over each side... ...seems doable.

BUT BUT BUT you say, that isn't how balancing works.

AND AND AND... ...of course you are right.

For those who didn't see or don't recall with a few notable excepts (cough cough 71, 308 and I think 1 or 2 others) the way to balance on the bridge was to:

1. Get on the bridge (with goals in that case but it is the same idea),
2. Slowly move up the bridge.
3. Once the bridge (there was an automotive gyro in the kit that year some used, others just had drivers with skills) begins to tilt, move back X inches (3 or 6 I can't recall).
4. The bridge continued up, rocked and stopped. Balanced

IMHO this does NOT need to be a coordinated effort. One robot can do the moving, all that is needed is to move the total bridge CG.

Let's say that we need 18 inches of travel to cover the high end of my memory.

Where do we get 18 inches?

It is hard but not impossible.

If we move the end robots out 9" each that would put them at 15" hanging over the edge. Again, this is hard but hardly impossible. Even if the robots do nothing to make themselves asymmetric so that their weight is exactly at their center, the robot centers are 2" from the edge.

And that give 18" for the balancing robot to move in the middle

So... ...this is hard but not impossible.

And unlike the hanging year where it took a ton of coordinated effort to make it safe and practical get these added points, I think this is essentially the same skill that successful teams will need to balance a Box of Rocks** on the Coopertition Bridge so the work is already half done.

For what it is worth.

Joe J.

*maybe more maybe less but let's assume that FIRST intended to make that 3rd robot worth A LOT so that teams would find it worth trying but not SO MUCH that the game was won automatically with that extra robot. It seems to me that they have done that. I talk with one group of 10+ year veteran and they tell me, it is a ghost, don't chase it. I talk with another and they tell me FIRST has made a game that is nothing but 3 robot balancing. They can't both be right.

** If Mike Bastoni didn't coin this phrase he certainly made it his own. FYI, Bastoni's back in the FIRST Game! Welcome back Plymouth North! FIRST Team #23. Hall of Famers if there ever were ones...

[Daniel_LaFleur]

Originally Posted by Joe Johnson

IMHO this does NOT need to be a coordinated effort. One robot can do the moving, all that is needed is to move the total bridge CG.

While I agree that only 1 robot need do the balancing, It is a coordinated effort to know WHICH robot needs to do it, and where the other 2 position themselves to make it easier.

Also, the teams are going to have to trust one another, because if it's done wrong a robot can fall from 2' (and probably not land on its wheels)

[Joe Johnson]

Originally Posted by Daniel_LaFleur

While I agree that only 1 robot need do the balancing, It is a coordinated effort to know WHICH robot needs to do it, and where the other 2 position themselves to make it easier.

Also, the teams are going to have to trust one another, because if it's done wrong a robot can fall from 2' (and probably not land on its wheels)

3 robot balancing is an after lunch on Saturday activity. The practice fields are going to be very popular. If I were running an event, I would randomly assign time slots to the alliances.

As to which robot, I could be wrong but it seems to me that it has to be the middle robot doing the movement to balance. If for no other reason than I would not want to be the robot hanging off the edge that is backing up.

But... ...there are many ways to skin a cat.

The alliance capt names the tune and the other teams strike up the band.

Joe J.

[Joe Ross]

Originally Posted by Joe Johnson

3 robot balancing is an after lunch on Saturday activity. The practice fields are going to be very popular. If I were running an event, I would randomly assign time slots to the alliances.

At least some events start to tear down the practice fields immediately after picking on Saturday. I remember trying to practice lifting with our alliance partners in 2007 as they were trying to take the field down.

[rich2202]

Max points during autonomous mode: Unlimited

1) Each bot shoots their balls. Each inbounder then has 2 balls.
2) Get the 4 balls (2 off your bridge, and 2 off the center).
3) When those balls are shot, they have to be replaced by the inbounders, and you can keep shooting.

Also, it may be possible to get balls off the other team's bridge by touching only the ball. If you had a strong enough suction device, you could get balls father than 14 inches from the edge.

Hoarding

One hoarding strategy is to hoard the balls on your bridge. Once placed on your bridge, it is hard for the other team to get them without creating a foul. You could park a bot on the alley side of your bridge, and have it hold the bridge level.

I would argue that the placing of the ball on the bridge is controlling the ball, but once you let go, you are no longer controlling the ball. Thus, an unlimited number of balls could be on your bridge and not be considered controlled. To wit: The competition starts with 2 balls on your bridge, and no bot is considered to be controlling those balls.

I would also argue that controlling the bridge (keeping it from being tilted by the other team) is not controlling the balls.


Balancing strategy

1) design your bot (bot 1) so you can remove dead weight
2) prior to the match, remove enough weight to match the weight of another bot (bot 2).
3) Bot 1 goes on the bridge
4) Bot 2 immediately follows bot 1
5) Bot 3 immediately follows bot 2

Bots "inch" along. As soon as the bridge tips, you are balanced (within the tolerance).

I do not see another way to keep from flipping bot 3 off the bridge. You can't move bot 1 to the end until bot 3 is fully on. Thus, they all must inch along together.

By having Bot 1 and Bot 3 equal weight, you minimize the balancing problems. Ideally each bot has a center of gravity in the middle of the bot. Otherwise that may cause an imbalance that is hard to correct.

Having a high center of mass also causes balancing problems. As the center of mass will move as the bridge goes from tilted to flat. Thus maximizing the dead weight close to the bottom of the bot would be helpful.

[ThirteenOfTwo]

Originally Posted by rich2202

Hoarding

One hoarding strategy is to hoard the balls on your bridge. Once placed on your bridge, it is hard for the other team to get them without creating a foul. You could park a bot on the alley side of your bridge, and have it hold the bridge level.

I would argue that the placing of the ball on the bridge is controlling the ball, but once you let go, you are no longer controlling the ball. Thus, an unlimited number of balls could be on your bridge and not be considered controlled. To wit: The competition starts with 2 balls on your bridge, and no bot is considered to be controlling those balls.

I would also argue that controlling the bridge (keeping it from being tilted by the other team) is not controlling the balls.

If placing the balls in a location where the other team is penalized for attempting to retrieve them isn't "controlling the ball", it should be. Rule revision would be excellent here. Besides, if you got enough balls hoarded the other team would probably just eat the penalty and grab whatever's on your bridge. And I don't think getting a ball to stop nicely on the bridge will be very easy.

All of this hoarding discussion is great, but I think you guys are missing a rather fundamental point. Which is that hoarding balls is a bad idea.

Guys, your whole strategy is to lose on purpose. You are allowing your opponent to score while you deliberately refrain from scoring. In order to come out of that with a lead, you need to already have racked up ridiculous numbers of points, i.e. be better at scoring than them. If you are better at scoring than them, why are you not scoring?

There is literally no situation in which you can start hoarding and still be close enough to them to win by 3-robot-balancing (to their 2-robot-balancing) unless you are already winning. In which case you could keep it closer by continuing to score than by hoarding.

[GaryVoshol]

Originally Posted by rich2202

Max points during autonomous mode: Unlimited

1) Each bot shoots their balls. Each inbounder then has 2 balls.

Except they aren't allowed to touch them until Teleop starts. [G18]

[jm2713]

Boy, this thread sure has wondered far from the original topic of hoarding balls by Inbounders. But back to that topic:

People are apparently somehow assuming that
multiple players on each team may handle balls. Only one player, the
"inbounder" may handle balls. Pertinent rules:

[G04] Each FRC team provides up to four Players (a Coach, two Drivers
and an Inbounder).

[G31] Only Inbounders may contact Basketballs; each Inbounder may hold
a maximum of two Basketballs.
During Teleop, Inbounders must remove Basketballs from the Corral
immediately upon arrival. All
Basketballs in the Alliance Station must be held by Inbounders once
removed from the Corral.

[G32] During Teleop, Inbounders may enter Basketballs back onto the Court by:
a) passing though the Inbound Slots at any time;
b) throwing over the Inbound Station during the final 30 seconds of Teleop.

There isn't any room for interpretation. 1) only inbounders can handle
balls 2) Inbounders can hold 2 balls max 3) Inbounders must remove
balls from the corral immediately. #3 requires that the inbounder get
rid of any balls s/he is holding so they s/he can "immediately" remove
more balls from the corral. The only hoarding that can occur is if
there are no balls in the corral the inbounder may hang on to two
balls. There are only two innbounders in the game so the maximum
number of balls that can bo hoarded by inbounders is four.

Although as others have said, if the inbounder inbounds balls such that they remain in the alley and your alliance never retrieves them, they are essentially out of play.

[Siri]

Originally Posted by jm2713

There isn't any room for interpretation. 1) only inbounders can handle balls 2) Inbounders can hold 2 balls max 3) Inbounders must remove balls from the corral immediately. #3 requires that the inbounder get rid of any balls s/he is holding so they s/he can "immediately" remove more balls from the corral. The only hoarding that can occur is if there are no balls in the corral the inbounder may hang on to two balls. There are only two innbounders in the game so the maximum number of balls that can bo hoarded by inbounders is four.

Although as others have said, if the inbounder inbounds balls such that they remain in the alley and your alliance never retrieves them, they are essentially out of play.

1-3 are correct. The implication of 3 is incorrect. You can be holding one ball and still be able to pickup another, i.e. you do not need to get rid of "any balls you are holding" if you are capable of noticing when a robot is going to score in time to get rid of an equal number of balls. If one ball is entering, the "Corral" Inbounder may be holding 1 ball.

A good set of Inbounders will know when balls are coming. You do have decent lead time considering you know when shots are coming, and may shots, especially rebounds, we be a little slow getting into the corral. It's not easy, but it's entirely plausible to have the "Inbound Slot" Inbounder push balls out and and recieve "Corral" (and potentially "Middle") Inbounder's ball's just before new ones enters the Corral. Thus, good Alliances can essentially hoard up to 6 (though more safely 5). There will be Inbounders trained enough and alliances coordinated enough to do this.

Also, if there's no Alliance robot guarding the alley, Inbounded balls are completely in play to both Alliances.

[Racer26]

Am I the only one that doesnt see balancing 3 bots as that big of a deal?

Yes, they'll have to be smaller than max dimensions.

Most bots are within 5 lbs of one another in weight, and you're balancing on a 6" wide platform. The CG's should be close 'enough' to the middle that I think if you can drive the 3 bots on (by having 3-a-bot push 1-a-bot and 2-a-bot from behind), the balancing will take care of itself, as the weight distribution will by definition be /fairly/ close to equal. a 6" wide flat fulcrum is going to mean that your 'balanced' state will have a fairly big tolerance window.

[Daniel_LaFleur]

Originally Posted by rich2202

Max points during autonomous mode: Unlimited

1) Each bot shoots their balls. Each inbounder then has 2 balls.
2) Get the 4 balls (2 off your bridge, and 2 off the center).
3) When those balls are shot, they have to be replaced by the inbounders, and you can keep shooting.

Incorrect. Inbounders may not touch the balls during Hybrid

[G18]
During Hybrid, Players may not touch Basketballs.
Violation: Foul

.
.
.

Originally Posted by jm2713

[G04] Each FRC team provides up to four Players (a Coach, two Drivers
and an Inbounder).

1 inbounder per FRC TEAM
3 FRC Teams per ALLIANCE
2 balls per inbounder =
6 balls hoarded by inbounders of 1 alliance.

... and I still say they will get a penalty as soon as the opponent scores another basket as an inbounder cannot inbound a ball and immediately retrive a ball from corral at the same time

[Siri]

The GDC at least started to answer this on the Q&A. I'm not sure I'm satisfied, but they seem to indicate it's not penalizable as long as you rectify the situation as quickly as possible?

Originally Posted by Q&A

Q. What is the definition of immediately? Suppose that 7 balls are scored in rapid succession. Each inbounder may hold 2 balls at a time, which means that the ball coral cannot be emptied immediately. So, how fast do the inbounders have to empty the coral to be considered "immediate"?
A. In that scenario, the Alliance would need to rectify the situation to be in compliance with all Game rules as quickly as safely possible.

Nothing yet about deliberately hoarding 6.

[nssheepster]

Um, I can't seem to find the number, but I belive there's a rule which just says, basically, that actions against the spirirt of first are a yellow card, or something close to that. So, hoarding may be possible, but I don't think it would be in the spirit of FIRST. Right?

[BrendanB]

Originally Posted by Joe Ross

At least some events start to tear down the practice fields immediately after picking on Saturday. I remember trying to practice lifting with our alliance partners in 2007 as they were trying to take the field down.

Not to mention if it is open you'll have 7 other alliances trying to get on that field as well. 10 minutes on the practice field for each alliance means one alliance won't be on that field if not two if you have an hour break (I have been to regionals where there was 20 minutes from selection to quarter final 1.

[BrendanB]

Originally Posted by Joe Johnson

Paul,
3 balancing is worth 20pts*.

My read is that that is about right.

The task is hard but not TOO hard. The points are high but not TOO high.

What is it going to take to get 3 robots on that 88" bridge"

Assume robots fill the given space, with bumpers robots are roughly 44" by 34" give or take.

If enough teams go wide (34" up the bridge), then you have 6" hanging out over each side... ...seems doable.

BUT BUT BUT you say, that isn't how balancing works.

AND AND AND... ...of course you are right.

For those who didn't see or don't recall with a few notable excepts (cough cough 71, 308 and I think 1 or 2 others) the way to balance on the bridge was to:

1. Get on the bridge (with goals in that case but it is the same idea),
2. Slowly move up the bridge.
3. Once the bridge (there was an automotive gyro in the kit that year some used, others just had drivers with skills) begins to tilt, move back X inches (3 or 6 I can't recall).
4. The bridge continued up, rocked and stopped. Balanced

IMHO this does NOT need to be a coordinated effort. One robot can do the moving, all that is needed is to move the total bridge CG.

Let's say that we need 18 inches of travel to cover the high end of my memory.

Where do we get 18 inches?

It is hard but not impossible.

If we move the end robots out 9" each that would put them at 15" hanging over the edge. Again, this is hard but hardly impossible. Even if the robots do nothing to make themselves asymmetric so that their weight is exactly at their center, the robot centers are 2" from the edge.

And that give 18" for the balancing robot to move in the middle

So... ...this is hard but not impossible.

And unlike the hanging year where it took a ton of coordinated effort to make it safe and practical get these added points, I think this is essentially the same skill that successful teams will need to balance a Box of Rocks** on the Coopertition Bridge so the work is already half done.

For what it is worth.

Joe J.

*maybe more maybe less but let's assume that FIRST intended to make that 3rd robot worth A LOT so that teams would find it worth trying but not SO MUCH that the game was won automatically with that extra robot. It seems to me that they have done that. I talk with one group of 10+ year veteran and they tell me, it is a ghost, don't chase it. I talk with another and they tell me FIRST has made a game that is nothing but 3 robot balancing. They can't both be right.

** If Mike Bastoni didn't coin this phrase he certainly made it his own. FYI, Bastoni's back in the FIRST Game! Welcome back Plymouth North! FIRST Team #23. Hall of Famers if there ever were ones...

Loved the detail analysis!

I agree with your statements from 2001 and the experience with the bridge; however, that is with one robot and two goals attached to that robot not three independent variables. If the middle robot does all the moving, they are having to push the other robots off the bridge to balance. I have a huge concern with a robot getting pushed part of the way off the bridge and can't make it back if it is pushed too far.