The Barrier Thread

[Grim Tuesday]

So lets talk about the barrier. The thing is a lot taller than you would think at first glance; 4". The 6" standard 6WD can't get over it, it would seem, though I would like to see someone do the math. Can the kitbot get over it?

Anyhow, how important do people think going over the barriers will be? And how do they plan to do so?

[Steven Donow]

Reaction while watching animation: "Pssh, it'll be easy, no different than going over the bump/ridge that divides tile and carpet(If that makes any sense)"

Reaction after : "So let's get to work on deciding our bridge-going over mechanism"

[the man]

A kit bot with 6in wheels could get over it if you had some spacers between the wheels and frame. This would raise the frame just high enough to let it get over. Not sure how bumpy it would be but it could work.

[mdiradoorian]

Actually you can get a 6" wheel over the barrier if you have the momentum and tread to do so.

[the man]

Well if you have all six wheels driven and a full weight robot I think it would be quite easy. maybe not very effective. Heck it might damage the wheels after repeated use.

[Duke461]

Originally Posted by mdiradoorian

Actually you can get a 6" wheel over the barrier if you have the momentum and tread to do so.

While I cannot give any proof on this, I can fairly certainly say you do not want to brute force over the hump; i feel you could have serious damage to your wheels. I saw teams break their wheels coming down from hard landings in breakaway.

[davidthefat]

Originally Posted by Duke461

While I cannot give any proof on this, I can fairly certainly say you do not want to brute force over the hump; i feel you could have serious damage to your wheels. I saw teams break their wheels coming down from hard landings in breakaway.

Yep, our 2010 robot broke one of her wheels.

[carrillo694]

Originally Posted by davidthefat

Yep, our 2010 robot broke one of her wheels.

Our team installed aluminum wheels at the front, which were able to sustain the weight of our full-weight robot coming down from the bump.

[VKP]

Our team is thinking of using four or six wheels, and using belts instead of chains. The belts will be backed on the bottom side by a flat panel, so that they can act as tank treads as they go over the barrier.

[Kusha]

I was thinking something like this: http://www.youtube.com/watch?v=Ktw6AZU2Wtk&t=0m36s whatever drive you'd like+ the threads in front that are shown in this video.

[arizonafoxx]

One thing I noticed is the bumper rules this year. If I read correctly the bumpers have to exist somewhere between 2" and 10" from the ground. It seems to me there is only one location for the bumpers if you are trying to cross the bump. The top of the bumpers would have to be at 10" and going down to 5" off the ground. This is the only way that the bumpers won't hit the bump first. As well your frame perimeter would need to clear the bump as well so your wheels are the first thing to hit the bump. The KOP frame assembled with 6" wheels and per the provided instructions will NOT cross the bump even with brute force since the first thing to hit the bump would be either A) the bumpers if the lowest part of the bumper is below 4" OR B) the frame would hit the bump which would be flat vertical metal hitting flat vertical metal. The provided 6" wheels with no extra elevation of the frame would only lift the frame 3" off the ground (actually a little less than that).

Rookie teams please investigate this fully before putting together the KOP frame. You will only create extra work if you don't think about this before hand.

[pfreivald]

Originally Posted by arizonafoxx

It seems to me there is only one location for the bumpers if you are trying to cross the bump.

This is only true in certain circumstances. It's not difficult to envision a situation where lower bumpers could be used, and yet the bump could still be traversed.

[Ninja_Bait]

Originally Posted by pfreivald

This is only true in certain circumstances. It's not difficult to envision a situation where lower bumpers could be used, and yet the bump could still be traversed.

Are you thinking of a mechanism that extends past the bumper perimeter, like a foot or a wheel or a wedge?

[Grim Tuesday]

Breakaway was a much higher drop, though.

EDIT: How would we do the math for this?

[slijin]

Originally Posted by Grim Tuesday

Breakaway was a much higher drop, though.

EDIT: How would we do the math for this?

I believe what you're looking for is shear stress analysis.

Originally Posted by lemiant

To everyone who thinks you can cross the bump unaided (that video shows what lifting the robot before the wheels hit can do) with 6" wheel, I'm fairly sure that is wrong.

If the side-profile of your robot is trapezoidal-esque - that is, you have powered wheels elevated above the ground - you'd be able to do so with 6" wheels.

I don't personally believe that people will break their wheels by anything, including driving into the rail (which is steel, as can be confirmed by the CAD) - if they do, it'll be because the wheels will have already experienced heavy damage - but I do expect to see wheels damaged by collisions and impacts. Plactions will crack very easily if you abuse them enough.