Los Angeles Regional Finals Match Defense
 

Hi CD, as I was watching the finals match at the LA Regional between 1197, 987, 5012 vs 294, 330, 1452, I noticed how significantly a defense bot can swing your match and in this case, decide the Regional Winner. 330s robot was flipped twice out of the three finals matches, causing 330 to lose many potential points in both matches, and perhaps being a reason that alliance lost both of those matches.

I was wondering how this might effect team strategy at future regionals, seeing that the refs were okay with harsh defense and didn't card the defending robot who was seemingly the reason for 330s tip. Thoughts?

PS I'm a first time poster, so please let me know if I'm practicing any ill advised posting methods.

Thanks!! :)

Re: Los Angeles Regional Finals Match Defense
 

I have not seen the matches in question so take all this with a huge grain of salt.

Usually a robot tipping because of collision with another robot is at least in part a result of an unusually high center of gravity on the robot that was tipped. If you are building a robot for a game where defense can be played, you should assume that defense will be played and design accordingly. At what point do we consider defense too vigorous or a robot to be poorly designed? I do not know. There is a little bit of blame on both sides of that I am sure.


Edit: you must mean 294 not 254

Re: Los Angeles Regional Finals Match Defense
 

I didn't actually watch the event, so I can't comment as to the topic until I watch some video, but did you perhaps mean "between 1197, 987, 5012 vs 294, 330, 1452" (bold edited)? 254 is currently competing at Central Valley, not Los Angeles.

Re: Los Angeles Regional Finals Match Defense
 

EDIT: GKrotkov beat me to it

Re: Los Angeles Regional Finals Match Defense
 

Yes sorry my mistake

Re: Los Angeles Regional Finals Match Defense
 

I was there and watched the matches in question. The teams involved could most likely answer this question better than I however in my opinion while 5012 was playing some aggressive defence, I wouldn't say that they were purposely aiming to tip 330. 330's robot is sort of top heavy when they have their arm/shooter up in shooting position which is why I think they were prone to tipping.

Just my 2¢.

Re: Los Angeles Regional Finals Match Defense
 

5012 has built a very impressive resume as being clutch in elims. I was at LA and these matches were incredibly fun to watch. 330 even managed to recover from one of the tips. I was shocked that they were still around and somehow dropped to the 23rd pick. bold prediction time: 5012 will be playing defense on Einstein.

Re: Los Angeles Regional Finals Match Defense
 

Very true, their robot was top heavy when the shooting mechanism was up

Re: Los Angeles Regional Finals Match Defense
 

It was definitely super exciting to watch, and it'll be exciting to see how 5012 performs at Champs

Re: Los Angeles Regional Finals Match Defense
 

Link to the first match of the finals: http://www.youtube.com/watch?v=IulNn2whPXw&t=54m2s

Tip #1: https://www.youtube.com/watch?v=IulNn2whPXw&t=55m55s

Tip #2: https://www.youtube.com/watch?v=IulNn2whPXw&t=1h31m55s

Tip #2 was pretty awesome because 330 was able to right themselves even though they were completely upside down.

Judging from all the matches during the regional, defense was a huge part in the winning alliance strategies. Pretty much every ranged shooter was struggling to make high goals when a defender robot collided with them during the shooting process. You can see this during the 3rd final's match when 1452 was easily harassing arguable two of the best shooters at the regional (before their robot lost connection :( ). 330's robot was unique because it braced itself against the bottom of the tower, making it nearly impossible to defend...

Until it tipped. From my memory, 330's robot only tipped 3 times during the regional, all cases during playoffs, and two in the finals. 330's robot center of mass was fairly high, especially when its shooter arm was fully extended. Combined with a nudge directly against it side, it isn't surprising that they fell over.

However, in one of the previous play off matches, a low center of mass robot was completely flipped upside down by a defender, and the defender's robot alliance was penalized with a dq for the match. When the same thing happened to 330 twice during the finals, myself and many others around me (even listen to the commentator) expected the game would be automatically awarded to 330's alliance by dq. The fact this was not the case brings up questions about the scope of defending. In a case of a tip, when is it considered a warning or dq? Hopefully other teams at the regional know more information regarding the subject.

So a few things to learn from the regional. Defending is very important, especially if the other alliance has a ranged shooter of any capability. Also, if possible, teams might want to consider creating a shooting algorithm where their robot is flesh against the bottom of the tower. Defense seemed pretty rough this year, so team should work on a case to deal with that.

Re: Los Angeles Regional Finals Match Defense
 

Disclaimer: LA stream was down during these matches, and I didn't see 5012 in action.

I have been thinking about this too, after seeing 3316 tipped during the playoffs in Israel. Without any "true" safe zones for teams to take advantage of, this sort of scenario is inevitable for tall robots. While it should not be the goal to tip your opponent on its back or side, defenders shouldn't have to show any less agression towards tall robots. Teams should design accordingly...

I am concerned about many of these tall robots and I expect to see a lot of rebuilds done before DCMP's/CMP.

Re: Los Angeles Regional Finals Match Defense
 

There is a VERY fine line between hitting a robot that produces a tip and continuously pushing a robot after it begins to tip.

5012 performed hit without intent to flip (as determined by the refs at that moment)
5089, as determined by the refs at that moment, intentionally pushed 3863, causing 3863 to flip in QF4-3 at Los Angeles. The red alliance got a red card for that match due to the flip.

Re: Los Angeles Regional Finals Match Defense
 

How does pinning apply to tipping? If a robot were to start a flip on a robot and cause an opposing robots wheels (or treads) to be off the ground it has prevented the robot from moving, wouldn't this meet the requirements of a pin? If so then it means that starting a flip is legal just finishing it isn't.
I dunno how I feel about that.

Re: Los Angeles Regional Finals Match Defense
 

I think you have a point there. So you can hold them in the air for a couple of seconds then back off.

Re: Los Angeles Regional Finals Match Defense
 

I don't know if it's just me, but it looked like 5012 helped 330 get into a better position to right themselves after they tipped in F3. If that's true, I'd say that was pretty classy of 5012.

Re: Los Angeles Regional Finals Match Defense
 

We (team 2443) played a similar defensive game in our eliminations finals run in San Diego. Funny thing, we initially only played defense because our intake arm broke in QF causing us to not be able to shoot (the reason we got picked). We played the opposite spectrum of the game, defense, great in my opinion, letting us beat alliances we previously thought were unbeatable like 3255's second seed alliance. Our defense mightve been the reason we made it so far and we even took a decisive game in the finals, but in the 3rd match we got penalized for pinning (arguable, but totally the refs judgement). The match was totally even in scores except for foul points and loss by 5 pts.

We found defense to be really hard to play against since vision is already a problem, driving around more defenses which if you don't have an experienced driver brings a second challenge. Probably if we didn't play defense, the finals wouldn't have been as in our favor. I feel if robots only have one definite shooting position they may be more vulnerable to defense. It matters where but a robot could block and force ill advised shots. Then again, you can't not have a shooting position because you can just get pushed around. The perfect shooter will have multiple comfortable shooting positions where they can be flexible and accurate.

Happy for TorBots' alliance for pulling it off in the finals. Unfortunately we couldn't watch it because the stream was down.

Re: Los Angeles Regional Finals Match Defense
 

This is quite a hornets nest. I have always felt that high speed ramming/tipping is not a defensive strategy but a strategy to disable/damage.

Consider a robot traveling the length of the field at full speed to hit (supposedly to defend) an opposing alliance member. Is this good defense or is it trying to cause damage? I am not saying that aggressive defense should be penalized, you can be aggressive without damage. This is way it is such a hard rule to enforce, was there intent?

Think about the events you've attended. When a robot crossing a defense carrying a boulder pushed another boulder through as well did the referees pause to think "Was that intentional? Was the driver able to see that there was a boulder in his path?" No. They assess a penalty and move on.

The referees have enough to do already without having to make this determination.

One last thought, Remember Gracious Professionalism. Act like your grandmother is watching and think about how you would feel if it was your robot was put out of commission.

Re: Los Angeles Regional Finals Match Defense
 

On the flip side this punishes teams that scout out drive bases and drives in disruptive and not destructive ways.
If someone makes the call to full speed clip another robot in an attempt to spin them out to someone who doesn't know whats going on it just looks like a missed full speed tbone. To the driver it was a perfectly executed pit maneuver. Intent is truly a weird thing.

Re: Los Angeles Regional Finals Match Defense
 

Touching the outerworks is the safe zone that we we designed for specifically (as well as the extended shooter to remove the possibility of getting blocked in that spot). In the 2 QFs we got 25 penalty points in that spot (and still made the shots). The refs at CVR were good about calling that foul.

Re: Los Angeles Regional Finals Match Defense
 

Bummer of a situation, both tips looks worty of red cards based on historical precedent (or at least the second one). Not saying the tips look intentional, but I've seen similar ones called before.

330 has been on the wrong end of this call (or no call) twice now.

http://www.thebluealliance.com/match/2007cmp_sf2m1

Re: Los Angeles Regional Finals Match Defense
 

Purposely damaging/tipping another's robot is unacceptable and against the rules. That being said, defense and ramming is part of the game. Build your robot robustly
Distance traveled is (should not be) the deciding factor. Penalties are (and should be) situational. A full field charge can be far less damaging the, say, a 'little push' on a robot that is almost tipped on the polycarbonate barriers.
Intent is not part of those rules, but is part of the 'vigorous robot-to-robot interaction' rules.
I'll say this again. Gracious professionalism should be used to measure your own actions, not someone else's. If my robot was 'put out of commission' by a legal hit (even a full field charge) I'd look at my design to see how I can make it more robust.

BTW, I have had my robot 'put out of commission' that way. ;)

Re: Los Angeles Regional Finals Match Defense
 

Unfortunately, it was a bit worse than that :(.

Here's a play-by-play using this video of what I'm pretty sure happened:

• 1:30:55 - We collide with an opposing robot, which takes our bumper off and drags it to the rock wall.
• 1:31:10 - Opposing robot drives back over rock wall, dragging our bumper with it into view.
• 1:31:38 - Refs notice the bumper and emergency stop our robot
• 1:31:47 - Volunteer wearing black at the top right side of the video tells us what happened.

I (the driver) didn't even notice the bumper until the volunteer told me about it. Here's a photo of our bumper attachment point afterwards (it was an 8" bumper so we only used one bracket, a mistake we won't repeat). As you can see, one wood screw was sheared off and the other ripped straight out of the wooden backing. Use more screws people!

Anyway, just wanted to post this somewhere because not many people know what happened and how important bumpers are!

Re: Los Angeles Regional Finals Match Defense
 

In regards to cards for aggressive play... A team at North Shore was given a yellow card in their first match of playoffs for an aggressive hit while attempting to score a boulder in the enemy courtyard on an opposing robot playing defense. The two robots pushed head on into each other until the defense bot was lifted up so that only its rear wheels and rear bumper were touching the ground. The offense bot backed away before the 5 second mark that would cause a pin. It was fully within the right of the referees to call what they deemed excessive aggression, but this scenario was at least worth mentioning. Seems to be just one more thing referees are inconsistent on between events.

One more thing worth noting is that the entire situation was not visible to the offense robot's drive team, considering there was a sally port in defense position 2 blocking all view of what was happening.