G13, G44 and Pinching Rollers

In the finals on Archimedes, 201, 33, and 148 got a G44 carrying penalty both matches. Both times, 33 had a ball in possession, and if I remember correctly, was pushed up the bump by 233 or 254 so that the ball was no longer in contact with the playing field. Both times, they released the ball (by kicking or just letting go… I can’t remember) as soon as they realized they were “carrying”.

Now, rule G13 (Causing Penalties) states "The actions of an ALLIANCE shall not cause an opposing ALLIANCE to violate a rule and thus incur PENALTIES. Any rule violations committed by the affected ALLIANCE shall be excused, and no PENALTIES will be assigned. ", essentially that if a robot causes another robot to break a rule, no penalty will be assigned. So, the question is, **wouldn’t pushing a robot with a pinching roller in such a way that caused it to carry a ball be an example of causing “an opposing alliance to violate a rule”? **

(In case anyone’s wondering, this is one of many times the refs disappointed me. Please don’t argue; I can cite several more examples, and the reason I’m not is that they’re volunteers, and they give up lots of their spare time to help us out.)

Oh, and penalties were assigned both times.

In my opinion you’re right in this case. Although on a different note, I’d prefer we not dwell on the past seeing that competition season is officially over.

We had a qualification match against 148 in Archimedes. We pushed them onto the bump so that they were obviously “carrying” the ball. There was a penalty that match but it wasn’t because of that. Just wanted to share.

I’m obviously not an impartial source but I was field side directly in front of 33 when they got called for one of those carrying penalties. They were not being interacted with by another robot and were not against a bump. I saw the ref signal it and I saw the ball come up off the ground a bit. It wasn’t very blatant, it’s not like it was 2" off the ground-but you could see it come up.

That said, it wouldn’t surprise me if the same thing had occurred to us at some point as well and it got missed or was given a pass. Our roller system is designed so it’s nearly physically impossible for this to happen, but sometimes weird stuff occurs.

It seemed like for the most part the attitude of the referee crew on Archimedes was to let the teams play unless there was a very clear violation. Overall I thought it was the best reffing I had seen at any event I’ve been to this year, and maybe over the last two years.

If I read correctly, I think you’re correct. I’ve recorded videos of every elimination round 201 was in, so I’ll look those over sometime soon.

I thought the reffing was fantastic on Archimedes. I have no complaints about any of the calls in our run. We got beat in two very tough matches against an incredible alliance!

I don’t think so.

If your robot picks the ball up off the ground, it’s a penalty. Another robot pushing you up the ramp didn’t cause your rollers to keep a hold of the ball.

The reffing was indeed excellent during the elimination rounds. They did scare me after that first match of the eliminations when we thought we had lost. I was relieved when they corrected it.

I agree, the reason the penalty was called was because the defending robot did not directly cause the picking up of the ball. True the ball wouldn’t have been picked up if it weren’t for the defence, but the mechanism caused the ball to be lifted not so much the act of the other robot pushing.

I think each year, many robots are built for intended purposes, and when the opposing alliance forces you to into a situation like that, then it is not the fault of the robot.

There are arguments for both sides, and I think that the easiest way would’ve been to talk to the head ref right after the match and see what really happened.

  • Sunny

“Dwell on the past” has a negative connotation that doesn’t seem to reflect the tone of the original post.

Provided the discussion is civil, it is productive and useful to have such a dialog. Some good may come of it.


I see the use of pinching rollers this year as a high-risk, high-reward gamble for those that chose to employ them, and was sort of the elephant in the room all season. Some had the flexibility or verticle freedom to leave the ball in contact with the ground when the robot experienced small bumps or elevations. Some did not. If you chose to grip the ball, you were making a judgement that the benefits of doing so outweighed the risks of incurring penalties when your robot experienced motions that caused the ball to come out of contact with the carpet momentarily. For those that had no flexibility in their gripper, it was almost a given that at some moment in the match they would experience some motion that would cause them to technically carry the ball when bumped by another robot, when going over a small lip or bump (such as the lip in front of the bumps), when tilting slightly through their own movements, or when pushing a ball into a goal. The real question was whether the referees would catch these momentary lifts, or whether they would interpret them to be penalized lifts. In my opinion, incurring a penalty because another robot bumped you when you were gripping a ball is not the kind of situation that is being refered to in the “one robot cannot cause a penatly for another robot” rule. Significant contact between robots is expected and part of the game. If it was the nature of your gripper that such robot contact caused you to lift the ball, then that was a vulnerablility of your design and a risk you chose to take. In our case, we interpreted the carry rule as absolute, and chose to capture the ball against the carpet so that is was impossible to inadvertantly carry. But we recognize that a pinching roller was an effective and worthwhile tactic for those that did it well.

Pardon me for veering off the original topic, but I have a related question and comment.

The question: If a “red” robot was parked on top of the bump next to the “blue” home zone, would/should they be penalized if a red robot pushed them off the bump and into the blue zone, making them the 2nd red bot in the blue zone? Is that part of normal contact or is that forcing a penalty? (For example, if my alliance is playing against 469 at the MARC and we put a robot on the bump right next to them, would we get a red card if somebody pushed that bot off the bump?)

The comment: There has been a lot of discussion about robots that are inherently capable of violating rules which are difficult for the referees to judge (2010: 3" incursion, active mechanisms above the bumper, multiple ball possession, pinching roller; 2007/2008: envelope violations, etc.). In my opinion, unless a feature or capability is specifically forbidden by either the robot rules (inspector’s call) or game rules (referee’s call), teams have the right to risk penalty in exchange for enhanced capability - as long as there is a legitimate/legal use for that capability. However, I think these teams should expect that referees will rule against them in the case of a close call. (For example, a robot with a wide ball collector that is posessing one ball while it “herds” another with the same device does not deserve the benefit of the doubt.)

Absolutely right. Everyone has the right to push the envelope, that is what sometimes separates the good robots from the great. Any penalty-capable feature is a calculated risk. You can be sure there were many momentary lifts by pinch rollers this year that were not caught by referees. Judging how far you can push a rule is a design decision we face with almost every game. Just one aspect of predicting what the gameplay will really be like.

If that’s the case I apologize. I remembered a lot of jostling, and I remember the bumps being the cause of the ball-carrying, and I guess I inferred subconsciously that 33 got pushed up the ramp :rolleyes:

and when I said I was disappointed in some referees, I was referring to earlier competitions. There was an instance where our hook missed (during the finale), and ended up hanging 5 or so inches outside of our bumpers, and the refs called a penalty. Afterwards, we pointed out that robot is allowed to expand to the finale configuration (eg. go outside bumpers) during the finale, * the head referee * said that you could only get wider in the space above the robot O.o we then showed him the rule, and he waived the penalty. I would understand if it were in the earlier competitions, but I believe this was during the Michigan State Competition.

@ Wayne: If it was obvious, I would assume not. That said, I wouldn’t put someone who’s easily pushed around in that precarious position :wink:
And if you’re attempting to find a way to defeat 469, I would suggest looking into what 294 did… they were amazing. Somewhere in the thread below, the driver coach (I think) for 294 described their strategy.


I don’t advocate pushing the rules in hopes of slipping something past the referees. I just wouldn’t write off a good idea because it introduced he possibility of a penalty. Many pinching roller ball collectors didn’t compensate for irregularities in the floor and “carried” balls for brief periods. I think they deserved to get called for carrying whenever they did it, and the referees didn’t owe them the benefit of the doubt on a close call. Nevertheless, a functional ball collector that collects an occasional penalty is better than no ball collector at all. 469 may have gotten called for active mechanism above the bumper once or twice, but that doesn’t mean their ball deflector switch was a liability. 1918’s wide ball collector was physically capable possessing more than one ball at a time, but the ease of ball acquisition outweighed the risk of penalties and the occasional hassle of having to take evasive action.

My gut feel is that getting pushed in would be be considered forcing a penalty and not called. However, if the team that got pushed in did not try to immediately get out, it would then be a penalty. Getting pushed in isn’t an excuse for having 2 robots playing defense in the opponents home zone.

Yes this is exactly what I meant by a calculated risk/reward. We also had and extra-wide ball magnet that could easily possess more than one ball, but its extreme effectiveness in easy acquisition made it more than worth the risk. I don’t believe we ever recieved a multiple possession call, although I can’t claim for sure that it never inadvertently happened.