Low Bar

[Billfred]

Originally Posted by staplemonx

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

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.)

[New Lightning]

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.

[MrForbes]

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

[MrJohnston]

Originally Posted by MrForbes

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

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....

[Boltman]

Originally Posted by MrJohnston

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.

[Billfred]

Originally Posted by Karthik

The results of this poll are terrifying.

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.)

Originally Posted by New Lightning

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.

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.

[Joe Johnson]

Originally Posted by Billfred

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.)

The shape that you need to be able to get under to limbo is surprisingly complicated. If you are not using CAD or some sort of to scale drawings, you are going to be one of those teams I discussed above, that THOUGHT they would go under the bar but don't in the end.

First of all you have to ask if you need to go under the bar in FWD and REV and from which side. The envelope changes significantly if you face your robot toward the opponent's tower or toward your own because (thanks FIRST) the bar is not in the middle of the outer works.

A lot depends on your wheel base and wheel diameters and such but (SPOILERS) there is a V out in front of (and behind of) your robot that is not even close to 14 inches from the "ground plane" (i.e. the plane that your robot drives on if it were a flat floor). I don't have the CAD pulled up but I think for our particular chassis parameters, the base of the V shaped "keep out zones" comes close to the top of our bumper.

SO... really if you have some boulder collector device you plan on folding out in front of your robot while it's doing the limbo, you really really really need to be sure that you can limbo in the real world not just in your minds.

Word to the wise.

Dr. Joe J.

P.S. Getting your boulder mechanism hooked on the limbo bar counts as a Tortuga. I'm just saying...

[Billfred]

Originally Posted by Joe Johnson

The shape that you need to be able to get under to limbo is surprisingly complicated. If you are not using CAD or some sort of to scale drawings, you are going to be one of those teams I discussed above, that THOUGHT they would go under the bar but don't in the end.

...blah blah blah...

Dr. Joe, unsurprisingly, speaks the truth. That measurement was right for us, but it may well not be for you. Plan accordingly!

[Jared Russell]

Originally Posted by Joe Johnson

The shape that you need to be able to get under to limbo is surprisingly complicated...[snip]

Moreover, a robot that has been designed to fit under the low bar as a rigid swept volume may find that things work a bit differently at 10+ feet per second...and especially with bouncy wheels...

[s_forbes]

Originally Posted by Jared Russell

Moreover, a robot that has been designed to fit under the low bar as a rigid swept volume may find that things work a bit differently at 10+ feet per second...and especially with bouncy wheels...

We reconfigured the kit chassis to use pneumatic wheels and did lots of testing with it over the defenses with uneven terrain. Here it is crossing just an empty platform at roughly full speed with nothing in the way. We unintentionally flipped that drivetrain upside down just once, but it wasn't when going over the rock wall or moat... it was when we went full speed over an empty platform and tried to slow down at the end.

Crossing defenses is very dynamic, CAD doesn't really show whether a design will work or not. Adding pneumatic wheels just makes things even more unpredictable. We weren't at all happy with that 6wd pneumatic setup, we're doing something else.

[Monochron]

Originally Posted by s_forbes

Crossing defenses is very dynamic, CAD doesn't really show whether a design will work or not. Adding pneumatic wheels just makes things even more unpredictable. We weren't at all happy with that 6wd pneumatic setup, we're doing something else.

What about it were you unhappy with?

[Rangel(kf7fdb)]

Originally Posted by Monochron

What about it were you unhappy with?

For reasons explained in the video. For one, you have a severe loss of control and precision going over the defenses when the drivetrain is doing nosedives across the defenses. It also wasn't that great at going over slowly. In short we weren't satisfied with going over defenses if we couldn't do it in a fast AND controlled manner so we opted not to go with a modified kitbot. Even if it meant sacrificing build time that could have went towards something else like the shooter. It seemed/still seems worth it since the drivetrain is literally half the game this year.

[staplemonx]

Originally Posted by Billfred

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.)

Thanks, Did you scrape in both directions or just one direction?

[dradel]

Perhaps using phone to post and spell check is helping out lol

[IronicDeadBird]

Planning yes but I see some weird things happening when we run the simulation.