Low Bar

Not sure how this thread about the Low Bar got sidetracked into a discussion about 2-ball auton, but here is my question:

How many teams have actually practiced going under the Low Bar WITH the cloth barrier in place? If you have, how would you say that it affects your ability to successfully cross the defense?

Also - it may have been stated elsewhere, but please note that the Team drawings of the field specify black iron pipe as the weight for the curtain, while the actual field will have an aluminum pipe - quite a difference in weight!

Crossing defenses is not a problem with a good low bot and a HG shooter is definitely doable. The biggest “obstacles” are having to go further to touch the bar and scale (in endgame) also bumper placement. Everything else is doable. In fact its all doable and stay under 14.15" except during endgame.

It really boils down to can you design bumpers and a mechanism to scale. If teams are playing defense with a taller bot then you may be at a disadvantage however how many teams will play defense first off and secondly have a tall bot doing that sole task? I feel this will be a rare situation.

On the plus side limbo/low bot gives you pretty much automatic destruction of one defense or 25% of way to BREACH. Also it is likely lighter meaning less scaling (winching weight) issues.

I see a well designed low bot as a better choice than a well designed high bot for the sole reason it can cross a defense the High bot cannot ever in every match. All other things balance out. So well designed LB > well designed HB with all else being equal IMO

The only thing High Bot brings is defense possibility and possibly easier engineering solutions (crossing, goals and scaling) and bumper placement IMO and it seems other teams opinion according to the poll.

I think we will see more low/limbo bots than high bots this year from both less experienced and moderate to top end teams. Look at FRC champions lots of low bots through history they are prevalent.

I agree with most of the assessments above… However, I do see being short enough to go under the low bar as being a very important aspect of this game.

  • A robot hoping to advance out of District/Regionals has to be able to score points, even when allied with inept partners. There are two primary ways to do this: damaging defenses and scoring boulders.

  • If a bot is designed to primarily damage defenses, being low is almost mandatory - Being short allows to you easily damage one of the defenses with no manipulators required (or even a fancy drive train).

  • If a bot is designed primarily to score boulders, its design must consider from where it will acquire the boulders to score. The most reliable source will be its own secret passage - to which the most efficient path is under the low bar.

Though, being low isn’t “mandatory” - its not like all three robots on an alliance will likely be able to share the path under the low bar to the secret passage particularly well, being low doesn’t prevent other options (such as going through a different defense to attain boulders in the neutral zone; picking up missed shots in one of the courtyards or sneaking into the opponents secret passage to swipe a loose boulder)…

Yes, we have s short robot.

We are design for 14" did you see any issues with anything below that height when crossing in either direction?

The results of this poll are terrifying.

We built for 15 7/8", and we were just scraping; 15 1/2" probably would’ve done it for that robot. Your mileage may vary based on wheel placement and angle of attack. (I drove the robot for the reveal video, and I had better luck coming in at a slight angle than straight on.)

When I see this pole I get the feeling that plenty of teams have come to the relatively same conclusion and that is that the consistency of the low bar out weighs many other considerations when it comes to design. What I believe is that most teams say that “we’ll go under the low bar and then will just try to drive over some of the other obstacles and that will be enough for us.”

What I don’t think that many people have realized is that this will in fact not be enough in terms of a productive and winning robot. The robot will need to do something else. And making the decisions to go under the low bar limits your options in terms of other implements. A good robot, wanting to under the low bar, will need to be either able to shoot into the high goal or climb the tower in order to have any kind of value in eliminations.

Maybe. Or maybe the low bar robot will be able to get a lot of ranking points, by ensuring that the alliance will breach and capture, using the quickest and most reliable methods. Then they’ll be the ones picking the alliance for eliminations.

It will be fun to watch what happens

Thought 1: It’s a poll on ChiefDelphi, so it’s a small sample of a small sample.
Thought 2: It’s a poll on ChiefDelphi at the end of week 3, so it’s a small sample of a small sample whose sample could shrink even further by ship date. (I know 2815 planned to cross the center divider in 2012…right until about Thursday afternoon at Peachtree when we determined there was a frame member about 3/16" too low that we missed when designing.)

I think your list omits some ways teams can get into consideration at most events*, but I do agree on the core point: low bar alone doesn’t hang your banner. What it takes to do so will depend on what the top teams at your event didn’t do–because they’ll need that in order to achieve the breach and capture points.

(Consider: A captured tower is worth at least 56 points in playoffs, before autonomous or high goals or scales. Really at least 66, since someone had to get balls across the defenses to do this. Viewed in isolation, a breach is 60 before autonomous. I figure you’ll be able to win quite a few with a two-digit score from Week 0.5 until probably Week 2. After that, the phrase will be “breach and capture.”)

*Championship? MSC? IRI? Those are not most events. Start scaling and hitting high goals.

I would think this… However, it sounds like a LOT of folks are building short robots designed to cycle under the low bar and score boulders in one of the goals… If there are not very many robots that can effectively traverse some of the other defenses, one of those could find itself at the top of the rankings as it will always be in preliminary matches with robots that compliment (instead of duplicate) its abilities…

I think low bots fall into all categories and many who build them will be able to do all the defenses and still score goals and even scale . I is seemingly the easiest way to build a scoring kit bot for rookies, I’m pretty sure a majority of older team low bots will be very capable beyond the low bar given.

Remember all low bots can open the doors from behind too. So low gives you ability to destroy 1 and aid others on another defense every match.

In the end the poll results show an unwillingness to give up on a guaranteed scoring play and assisting on another at the bare minimum. High only helps in defense abilities due to height. But limbo bot may transform to high.


Why are folks assuming a robot that can limbo cannot cross other defenses as well? I understand, a little, why a low-rider may have trouble opening doors, lowering bridges or raising the portcullis but why would a low-rider have trouble with the other defenses? The low bar is not so low that it impacts wheel size choices. drive train choices etc.

yup, we seem to be able to get over them with kit wheels on a slightly modified kit chassis.

Why? We have room for a nice size electronics board, mounted near the top of the robot…easy access, etc. It took our electronics team about an hour to mount the parts and do the preliminary wiring.

Our robot can fit under the Low Bar and, in theory, should be able to cross every defense by itself, so it’s not impossible. However, this trade off my cause severe issues if we try to scale the tower as we’ll have to develop something to grab the rung, which may prevent us from going under the Low Bar after it’s added, which is also why we’re considering it to be removable.

If you do go under the Low Bar, it’s going to make doing other objectives harder, but not impossible.

I agree (being low actually makes many of these easier). But many people are justifying their choice to do the low bar by saying “you don’t even have to do anything special to the drivetrain!” Either you haven’t done anything special to your drive, in which case you’re going to have a hard time with the other defenses, or you have, in which case the point is moot, you’ve taken the time/effort to cross other defenses anyways.


I would assume for many reasons in my earlier post. There are going to be a lot of teams that will fail to meet their potential in other aspects of the game in pursuit of the low bar, and as a result, won’t be able to gain enough from doing the low bar for it to be worth the design tradeoffs.

This was not our experience, and I know of many teams sharing in our pain. There are factors that don’t apply to all teams (in our case, significant amounts of space dedicated to boulder pathways, and being unable to afford to do the whole robot on Talon SRXs). I’ve seen worse, but there will be a lot of cramped boards this year.

I’m not Karthik, but from my experience in FIRST:

  1. Teams often have trouble doing basic game piece manipulation. Throw in the low bar, and you’ll have teams be even worse because now they add in the design constraint of going under the low bar.

  2. Doing the low bar means you’ll likely have to compromise on some other game objectives.

I’ve just seen it as a design challenge so far: how do we fit all the stuff into a compact package? It’s been challenging for our team but the process has been positive and productive. Having a low height constraint has the side benefit of preventing other problems (high COG). Hm.