Best way to estimate the best defense bot

[goldenglove002]

It's probably not the best method, but I had our scouts watching for collisions between robots. Give a point for a collision won, take a point away for a collision lost. Find the ratio between the two.

While this has it's imperfections, it gave us a pretty good idea of which robots had the ability to play valuable enough defense and which would just get pushed out of the way.

It's not easy to quantify defense and this year it's really just best to figure out who has a defensive strategy, then watch to see if they are actually any good at it. IMO, picking a robot to play defense in elims over one that can score is a bad strategy unless it is clearly a strong defender (strong enough where you don't need numbers to realize it can play defense).

[arbym]

We view defense from an offensive slow down of the opposing alliance. We log all defense events that happen (blocking movement, nudging while shooting, etc.) and correlate back to the offensive team. We then display those statistics as shooting percentage and shooting percentage while defended. We also look at the cycle time from pickup to shoot, to pickup and compare defended vs. undefended. Because we logged the event who was defending we can show who caused the offense to decrease. All ties back to our real-time scouting effort.

[themccannman]

Originally Posted by arbym

We view defense from an offensive slow down of the opposing alliance. We log all defense events that happen (blocking movement, nudging while shooting, etc.) and correlate back to the offensive team. We then display those statistics as shooting percentage and shooting percentage while defended. We also look at the cycle time from pickup to shoot, to pickup and compare defended vs. undefended. Because we logged the event who was defending we can show who caused the offense to decrease. All ties back to our real-time scouting effort.

If you have the resources to do this, it is a great method for tracking defensive capabilities of robots. The only problem is that it only tells you how well robots that play defense do, not how well they could play defense if you asked them to. Some of the best defensive robots are the ones who never play defense until elims.

[Tom Line]

We've found that generally speaking, scouting for a 'good' defensive team is a factor of a couple things.

Obviously, the first thing you require is a good drive train.

Next in our experience is how well that team has worked with us. We get a chance to be with most teams in the qualification matches, and we know most other teams from previous experience. How receptive their drive-coach and drive team is, and how well they can carry out a plan, is immensely important to us.

This year, modifying any robot to block is fairly easy while keeping a low cg. That plus a smart drive team and coach, plus a nice 10 point hang will get you on just about every defensive pick-list out there.

[bduddy]

Originally Posted by fox46

However, in recent years FIRST has been steadily reducing the attractiveness of defensive strategies. In this year's game, a good defense doesn't score you any points.

I'm not really sure what you mean by this - in most FIRST games, and indeed most games, period, a good defense doesn't score you any or many points. Good defense keeps the score low, hopefully to an extent where your remaining robots can win the game. And I agree that in the last couple years FIRST has reduced the attractiveness of defense, through not only protected zones but also the ranking system, but lately, and especially this year, this is not the case; having lower scores only hurts you in tiebreakers, and because the first tiebreaker is autonomous (unaffected by defense), it's unlikely to matter at all. Yes, there are still plenty of protected areas, but a good defensive robot has more potential than ever before to rank highly.

[Justin Shelley]

Our robot played defense these year at STL regional because our climber broke and we couldn't feed we never scored a single point in teleop and were ranked 28th, but even still we were the second pick in the whole regional!!! We thought that it might even be the first time a robot that has never scored a teleop point was picked so high. Anyways here's some videos of our robot defending with our 6wd pneumatic, 2 cim, toughbox drivetrain

1) http://www.thebluealliance.com/match/2013mosl_qm75
the full court shooter usally put up around 120pts, they were second seeded team. Also their shooter would shatter lexan at 80% power so we had to have something beffier to defend them with. and yes i did commit a foul by running across field after them heat of the moment thing and the only foul we got the whole regional

2) http://www.thebluealliance.com/match/2013mosl_qf3m2
we are robot that starts on left for red alliance

3) http://www.thebluealliance.com/match/2013mosl_qm81
we are robot that starts on left of blue alliance

Rate me please?

[2789_DrT]

I'm one of the scouting mentors for FRC 2789 and I've been recently brainstorming new ways to analyze our data to pull out the effects of defense so our team can illustrate what we do best. We currently have a system that's good at gathering quantitative data to rate offensive bots and qualitative data to help our drive team play effective defense. We don't have a system in place that can use quantitative data to rate defensive teams because we're looking for our counterparts this year and we primarily playing defense.

It's been a big headache to find methods that work because so many variables impact individual and alliance scoring and because defender bots can play different roles that impact these stats. Depending on the match dynamics, a defender may be expected to play zone defense, man-to-man defense, to set picks for other shooters, or various combos of the above.

I'm so glad that there are teams going to Champs that have systems that are sophisticated enough to take this problem seriously so I can stop worrying about this and trust that you will find us.

However, because it's fun to geek out, here's what I'd do if I really had to find out who were the best defenders on the field with a small scout team. [ Full disclosure: a lot of what I'm going to say is informed by changes our team has implemented that have improved our defensive play from good to great - so if you do these things, you may just find us ]


YOLO WAY TO FIND GREAT DEFENDERS:

• send scouts into the pits and look for robots with low centers of gravity, chassis with at least 4 cims, and several optional blocking devices that can be added to or removed from the robot for different situations

• send scouts into the stands to take a peek at other scout systems. Look for teams that gather qualitative data that can give their drive teams the intel they need to play shut down defense. For example - my team's scouts gather things such as robots' favored movement patterns, favorites feeds, favorite shooting spots, the accuracy in those spots, etc.

Tell scouts match scouts to look for the following:

• drive teams that know what angles / pathways are good for efficient zone defense

• drive teams that have the skill set to play effective man-to-man defense

• drive teams that know the rules - these teams play aggressively within the rules and have drivers that head quickly to the question box whenever it's necessary to seek clarification on controversial calls

• drive teams that know how to set picks and know when to set picks and when to play defense

[Citrus Dad]

Originally Posted by 2789_B_Garcia

themccannman & MrJohnston, I'm the lead mentor and drive team coach for a defense-oriented team. If you have time, I'd be interested in your opinions on some match footage to tell me what you think about our team! I agree that OPR and DPR aren't helpful or accurate, and I've also used a more qualitative system for making defense strategy decisions.

Out of curiosity, why do you think the best defensive robots don't play defense during quals?

Our robot, Citrus Circuits, is a case in point. This year our shooter failed mid match several times. Each time we turned to play defense and completely shut down the opposing alliance. In two matches, we held off 2 other robots and didn't allow them to score more than 3 goals the rest of the match. Yet, we are usually the top scorer in our qualifying round alliances. (We get paired with high scorers in the elimination rounds.)

And it's not just defense, but also counter-defense that we look for. That was key when we selected 295 in Madera. They protected our FCS 840 who emptied the magazine several times. 295 wasn't playing much defense in qualifications, but showed excellent driving skills.

Send the video--it would be fun to look at!

[Louisiana Jones]

Originally Posted by dellagd

Im sprucing up our scouting system for our next event and would really like do work defense into it.

As of now, we have 6 scouts (+ a head scout but he/she does different things), and they all watch every match.

I have heard of DPR, and have a crude understanding that its basically the same calc as OPR but using the opponents score, but Ive heard this is inaccurate.

I could give each scout a slider of 1 - 5 in "How well does robot play defense", but this is purely objective.

How does your team do it? Is DPR actually useful?

I'm a newbie at scouting, but after working this year with a student to create a scouting system for our team to use, we have determined that OPR is the single best indicator of the offensive/defensive capability of a robot. OPR is misnamed. Everything we have tested indicates that it accounts for both the offensive and defensive contributions of a robot to a high degree of accuracy. While there are some weaknesses with OPR the advantages are that it is easy to calculate with available data that doesn't need to be scouted, and when combined with data from your scouts can give you a perfect idea of the offensive and defensive contributions of a robot. DPR is also misnamed and therefore seems inaccurate when used to describe how good a robot is defensively. DPR isn't simply a defense ranking, and if you try to use it that way will always seem inaccurate.

[EricH]

Originally Posted by Louisiana Jones

I'm a newbie at scouting, but after working this year with a student to create a scouting system for our team to use, we have determined that OPR is the single best indicator of the offensive/defensive capability of a robot.

For this year, it might be (I remain unconvinced of OPR as an indicator of the best robot, particularly when planning elimination strategy).

For next year, it might not be. There are some years where OPR works well, and other years where it's as bad as the W-L-T seeding system with too few matches (like 8!).

[SkittlesCharge]

To keep track of defensive bots this year, we used both pit scouting and match scouting. We rated the drive train's speed, pushing power (torque), and manueverability on a 1 to 5 scale. Then we also kept track of the number of times the robot pushed another robot, blocked another robot, pushed a robot while it was shooting, and blocked shots to see what kind of defense it played.

While we didn't get to pick partners at any regionals this year, but it seemed to work fairly well. Except for two easily fixable major problems (the 1 to 5 scale's default was 1, making many average robots look bad and in pushing matches back and forth it was hard to decide the number of pushes to award the robot), the system could tell us how good a robot was at blocking full court shooters, or if it tried to push robots frequently, but was just too slow to catch them, etc.

I wouldn't recommend using a system exactly like ours was this year, but hopefully an idea or two from it would be helpful to you.