[YMTC]: [YMTC]: Bumper-to-Bumper Tipping

Well we had some controversy </Fallon> at the Finger Lakes Regional this past week. To keep discussion of “did the refs make the right call” to a minimum, I will not share what the official ruling on the field was.

We have one robot on the red alliance (let’s call them 3015) lining up in their opponent’s courtyard to take shots at the blue tower. Now 3015 prefers to not use vision when lining up their shots so they need to make sure they are at the right mark every time.

Blue knows this, and sends a defensive robot (let’s call them 2010) to play some defense against team 3015. After a some back and forth contact between the two teams, 3015 goes to line up for their shot while 2010 lines up to play defense. The two collide, bumper-to-bumper, in the middle of the blue courtyard where one of those robots ends up on their back.

If you’re a visual person: https://youtu.be/HGs0atRJm5Q?t=59s

One referee throws a penalty, one referee says the hit is clean. Did one of the robots go too far? Was there intentional aggression behind it? Or is this just an unfortunate incident?

What happened guys?! You make the call. ::rtm::

Looks like under a half second to me. That’s not enough time for most drivers to realize a flip was about to happen and back off. My vote is clean.

Clean hit here as well clearly both teams were driving into each other at the point of the tip, and neither driver had the reaction time to save the tip.

Looked clean to me too, not intentional.

We had the same problem during the playoffs at North Shore where our robot was being defended against, back and forth bumping etc trying to shoot. The other robot happened to be top heavy and tipped and we got a yellow card.

It was similar to this where were just driving forward and backed up, it was not intentional but we were penalized for it.

Clean hit for sure. Not even close.

What really seals the deal for me is the presence of two drawbridges on the field. This makes it very unlikely that the drivers could even clearly see the interaction happening in time to stop it.

If the driver did not back off, hit the underside of the robot, did extended pushing, etc etc it might be different, but particularly with the drawbridge in the way there’s nothing the drivers could have done to stop this.

228 was the offender in a very similar incident at RIDE this weekend, and it was a no-call. We didn’t even know there was a tip until 20 seconds later when someone opened the drawbridge and we saw the defender upside down.

Bumper zone contact is expected. Bumpers are variable in their distance from the floor by up to 3 inches, so it’s easy for a ‘natural’ wedge to form with the bumper apexes. There’s also probably a 50lb difference between those two robots. These are the facts, and both robots are 100% legal given the probable variables at play.

The subjectivity is how quickly the flip happens, and if either driver really had time to back off. Even my driver, with the best reflexes we’ve ever had on my team, would probably have not prevented that flip. Thus it falls to benefit of the doubt to both teams there. It happened too quickly for a foul to be called. Of course, this is IMO.

That is a fantastic point that a lot of people who aren’t down on the field don’t really understand. In fact, this video was the first time that I saw the incident happen. My vision, at the scoring table, was blocked due to, you guessed it, a drawbridge.

Clean hit.

Defender was aggressive and knew what they were doing. The reverse was like a second, and the arm wasn’t used in any way to lift or tip.


IMHO, neither.

G24 prohibits “strategies aimed at (the) destruction or inhibition”, so referees must judge whether the action is strategic, NOT whether the play was intentionally aggressive. I think the Head Referee in this case might have issued a red card because there is clearly “damaging contact with an opponent ROBOT on or inside the vertical extension of its FRAME PERIMETER” (red robot contacts bottom of blue robot after blue begins to fall backward); however, I think a red card would be incorrect, because the red robot’s action was clearly not part of a strategy aimed at destruction or inhibition.

The blue robot is tippy by design; i.e., playing defense with the arm raised shifts that robot’s CG up and to the rear – and their driver should know it. The Head Ref should have been able to recognize that, too.

Not only do I think the contact was clean (no foul on red), I also think red should have been awarded a G28 free scale because of contact by blue during the endgame (~2:16). Per Q869, “…, DISABLED or E-Stopped (or otherwise immobile) ROBOTS are not exempt from receiving violations.”

This was my exact thoughts as well, and a good example of why teams should try to get their robots as close to 120lbs as possible (while controlling for CoG), and mount bumpers as low as possible unless they have a good reason not to.

While intentional tipping is not allowed, teams should bear some responsibility to build a robot that resists tipping during normal robot-to-robot contact. In 2013 for example, I saw a team that had built a robot that was like 14" wide x 42" long x 50" tall, and it would tip CONSTANTLY, with just the slightest touch (and several times they even tipped themselves). The refs virtually (and correctly) never called penalties on teams that had caused them to tip though because it was clear the robot had not been built to handle normal gameplay, and almost no amount of force could be used when touching them that wouldn’t cause them to tip.

I agree with the majority on this one; this is definitely a clean hit.

I’m sorry, if a team builds a tippy robot and they go play defense, they are likely going to get flipped over. If they’re gonna have this rule, they should figure out a way to disregard tippy robots. Otherwise, what’s to stop someone from purposely getting the other team dqed so they lose the match?

Better angle and video quality here: http://youtu.be/nJYIjMDnbQ8

I concur - clean hit.
This is only my fifth season with FRC (fourth seriously so), but this seems to be the only year in this span in which bumpers have been placed so high on most of the robots. The game challenge this year resulted in robots with a high ground clearance and high bumpers, even though the average CoG was within or only slightly above the top of the bumpers. We’ve had alliance partners tent trying to help each other through defenses (esp category C), robots run themselves up against walls, flip themselves on batter dividers, and generally get turned every which way [strIke]but[/strIke] **including **loose. When two roboots meet in vertical bumper to vertical bumper contact and one robot winds up on its back, it’s not the other robot’s fault.

I really appreciate everyone’s perspective on this type of interaction which seems to be making an impact on a few teams this season.

Maybe as a community we can come up with solutions on how to make the determination of this type of penalty less subjective. Not sure if this means video review only on major red card penalties, implementing a rule that gives the offensive robot the benefit of the doubt (like in VEX), or maybe some other suggestion that someone in the community has to make the matches easier to call.

I think that the referees have one of the hardest jobs out there. They obviously understand the amount of effort and time that goes into building the robots and want to try to call each match the best they can. That being said, they are human and are going to make mistakes but we have to realize they are volunteering their time and really care about the program and what it stands for.

It is hard to see your team get knocked out of the competition when a call doesn’t go your way, and you should advocate for improvements to call making. But at the end of the day the refs are doing the best they can, and everyone should be aware of that.

I see no tipping foul as the ability to “back off” was not there thus I do not believe the tipping intent was there either. so my call as an observer of this scenario would be NO FOUL.

I think the way to think of tipping, is if the tipper had an opportunity to see the competitor tipping then backed off (no foul) also the tip happens with little to no reaction time then (no foul)

You likely get a FOUL when INTENT is there or the chance to back off was not heeded as a robot is tipping. (Foul and could be a RED CARD as well) or you had a specialized tipping extension etc.

In reality a lot of cheese caked bots end up top heavy so not surprised to see some defensive bots tip and that also creates opportunities for FREE SCALES it the tipped bot is touched in last 20 seconds on way to batter

The “tipping rule” specifically calls out “Strategies aimed at…”, and includes just about any “standard” method of disabling another robot.

The problem is that by saying “Strategies aimed at”, it forces the refs to judge intent. Generally, if it’s a single hit, the robot goes over, and the hitting robot was already scooting for the far side of the field, it’s not going to be obvious that there was intent. OTOH, if you’re pushing, the robot goes up, and you have a chance to back off but keep pushing, there’s at least a 50-50 chance that the refs rule the intent (and thus the strategy) was there and the head ref shows up in front of your player station with a card in hand.