Rethinking the Low bar

[GeeTwo]

Caveat: this is the eve of our first competition.

No way - I think we made all the right to-level choices. Things really came together tonight - we're driving and (manually) aiming with a camera now, and We have the driving (low bar, B, or D) if not aiming and shooting parts of auto working. We can make high goals more than half the time, with a fairly high arch, and low goals more consistently. The only real concern about making a solid run at the banner is the beating that the robots (and field) are taking this year, and building a tall robot would only have made those worse.

I'll try to remember to post a follow-up on Sunday.

[Boltman]

Originally Posted by GeeTwo

Caveat: this is the eve of our first competition.

No way - I think we made all the right to-level choices. Things really came together tonight - we're driving and (manually) aiming with a camera now, and We have the driving (low bar, B, or D) if not aiming and shooting parts of auto working. We can make high goals more than half the time, with a fairly high arch, and low goals more consistently. The only real concern about making a solid run at the banner is the beating that the robots (and field) are taking this year, and building a tall robot would only have made those worse.

I'll try to remember to post a follow-up on Sunday.

Go for breaches in every match.... get those 3 RP and keep practicing HG shots for eliminations. LG is A-Ok. Good Luck GeeTwo

[MetaEngineer]

Even as I am presented with ever more ways the electronic and pneumatic systems must shrink or move to accommodate additions to the bot, I still think it was the correct choice for us. As much as my grouching under time pressure would suggest otherwise, I have come to enjoy sharing an exercise in compact and rugged design with the students.

There are plenty of things I would love to change if I could rewind to kickoff, but all of those would simply be time, resource, and frustration savers for our design and not abandoning the low bar.

[Tom Line]

We'd keep it.

Like many lower numbered teams, we've had a lot of experience shooting balls. We took those lessons learned and incorporated them since day 1 and we were confident we could make it work.

It was a huge challenge for us to package everything. I hate some of the compromises we made in the wiring of this robot. We had no dedicated electronics area so everything ended up where it fit. That doesn't make for the cleanest layout.

We are still working on some of the trade offs. We have far too few pneumatic tanks and our compressor runs too much. At this point we have no more space, so we're going to live with that. That was the result of a late design decision after we had already calculated and committed to our tank capacity and mounting points - we were shocked to find the robot goes over the obstacles much easier with our arm in the up position (a higher center of gravity). Moving our large arm takes a lot of air.

We went with a near-sheet metal chassis (our first) to maximize space on the inside of the robot. That was a compromise that resulted in a chassis that is far more flexible than we expected. But as long as the welds hold we don't care .

It's resulted in the moving of our camera twice, our flashlight twice, and numerous rewiring jobs as we look for that extra inch of space.

We've gone from long cylinders to pancake cylinders on our AM PTO, and that's caused us a couple headaches re-engineering the connection points twice so that they don't unscrew themselves.

It's been fun!

[Boltman]

I think everyone should build a smaller bot at some point. We learned a lot in how to efficiently package multiple systems and electronics. It was definitely a learning experience and proved very effective going over obstacles without tipping . I am of the opinion a low bot can do anything as well as larger bots minus better defense. Most of the past world champion captains tended to be low to the ground bots. I think we may continue to go smaller and more compact in the future.

[Kevin Sevcik]

Originally Posted by themccannman

The only thing that determines when an object tips over is when it's COM passes outside of it's footprint projected in the direction of gravity (downward).

That's only true in the static case. It's possible to save a situation that would statically be a tip by accelerating or decelerating, which is the equivalent of pushing the CoM one way or another. You can also cause a tip in the same fashion. A heavier robot with more rotational inertia is going to tip less than a lighter one because your motors stay there same. I guarantee you I could build a chassis that flips due to its own wheel force, and fix it by adding weight without changing CoM.

[Legator91]

Yes. The low bar is one of the easiest ways to get through the defenses. By designing for it you also build a robot with a low CG. This then makes going over the other obsticles without tipping over much easier. Its worked well for us so far. It did take some extra time to design, but it was worth it.

[Trevor1523]

Right after we watched the reveal video on the 9th we went to 179's field to see what it looked like. When I saw the height of the low bar I looked at one of my team mates and said "There's no way we're fitting under that". I would probably still have the same reaction.

For me, the low bar is an obstacle that I personally knew most teams would design their robot for because "OOOOHHH WE GOTTA DO EVERTHIN'". So we decided not to. I think we would make that decision again. Even with our #tallbot we still had trouble packaging everything into what we built so kudos to all those low bar robots.

EDIT: I've been wanting to say this for a while and I feel like this is an appropriate place to say it:
The low bar is a defence, yes? Yes. So I looked at the problem as would we design our robot to just be able to damage one defence, say the Portcullis. That Portcullis design is essentially your constraint and you can't remove it, you can't work around it. It has to stay there. So we decided to not let 1 defence constrain us when there are 8 other ones that are available to take down. (I think that makes sense)

[MechEng83]

We would definitely take the low bar approach again. We looked at it from a strategy standpoint from district events through worlds. Add to that the design and engineering challenge of getting everything to fit in a tight package. It's a really good lesson in minimalist design. We opted to not have pneumatics this year to save space, and aren't regretting that decision at all.

We typically are crossing the other defenses in teleop, but we still wanted to be able to handle that one, as we might be paired with 2 robots who couldn't do the low bar. From our week 2 event, there were a few times we had to cross the low bar because an alliance partner wasn't able to complete it for one reason or another.

When we are in tower attack mode, it provides a quick path to go back and forth from the neutral zone and/or secret passage. We used it often (though not always) to make that trip.

Low bar isn't for everyone, but it provides a fun challenge.

[BotDesigner]

My team totally ditched the low-bar Saturday after bag and tag. We are using our withholding allowance to build a mechanism for Colorado that I believe should be able to change the way defense is played in this game.

[MaGiC_PiKaChU]

Originally Posted by BotDesigner

My team totally ditched the low-bar Saturday after bag and tag. We are using our withholding allowance to build a mechanism for Colorado that I believe should be able to change the way defense is played in this game.

let's see if you found what I found

[hardcopi]

We are a tall robot and to be honest I am still alright with that decision. Our biggest problem isn't the robot wanting to tip over it is that our drivers are afraid of breaking the robot so they keep stopping while going over defenses. This makes us "look" like we will tip. We are using the original AM wheels on our tracks and not so much as a crack (we made hubs to take the abuse).

[Monochron]

Without a doubt we would still plan to go under the low bar. We have had multiple matches this year where our ability to do the low bar directly added to our RPs earned in a match (in particular our solo breaching when we are the only robot on our alliance).

Self reliance is something I brought up in the old Low Bar threads and I am very happy to report that it was the right choice for us.

[Cothron Theiss]

If my team had the experience and the skill to make a fast, accurate high goal shooter, than we might have. However, we have a track record of building functional but not exceptional shooters, and this year, we just decided we didn't need to shoot high goals.
I am still happy with our decision as it forced us to embrace CAD more in our design process (something the rest of my team had been dragging their feet about) to get everything to fit under that 14" limit. Also, as long as the improvements to our intake we plan on implementing at the Regional work, we should be able to run low goal cycles very quickly, and crossing the Low Bar is critical to that strategy.

Oh, and we inadvertently built a robot that can climb stairs unassisted. That wouldn't have happened if we had gone tall.

[Ryan Dognaux]

We prioritized breaching and bouldering and that included the low bar. I wouldn't change a thing. Our robot is a breaching machine and could do 3 - 4 low goals a match at our first regional. The low bar allowed us to keep our center of gravity insanely low which made us able to zip over defenses with no worries of tipping.