How are you getting over the 4" bump?

[mega900997]

Hello,
So far, our team has been able to construct a mechanism to push the bridge down. We were planning on going over the bump as well, we have the mechanism in mind for it as well and we have the parts for it. What are your ideas on getting over the bump? And is it, or is it better to just stick with the bridge?

[Nick Lawrence]

Originally Posted by mega900997

Hello,
So far, our team has been able to construct a mechanism to push the bridge down. We were planning on going over the bump as well, but we don't know how to tackle it. What are your ideas?

I hate to burst your bubble, but I think this is a decision that should have been made weeks ago.

However, I think lots of teams are using pneumatic tires, or having wheel spacing geometry that lets them float over it.

-Nick

[wilhitern1]

We are using tank treads, but there are still some question marks that make us unsure that we will succeed.

[Jakal1391]

Three words. Eight-wheel-Drive!

[dellagd]

Pneumatic tires

[SteveGPage]

As mentioned above, if you haven't already built this into your design, you are probably not going to be able to do so this late into the design and build season.

My suggestion is to use what you have, instead of going over the center barrier, use your ability to cross the bridge instead. Make sure that works flawlessly, so you can cross from one side of the field to the other, as needed, plus have the ability to balance on the bridge at the end.

[mrlg220]

Pretty much, the chassis and bumpers should be high enough so the robot doesn't get completely stuck. Your wheels should be large enough in diameter as well (8" + is good)and/or you can add a skid plate or casters to lift up and push the front over. Your CG should be low to avoid tipping over while crossing.

[Aren Siekmeier]

Originally Posted by Jakal1391

Three words. Eight-wheel-Drive!

2 too few!

We have a mechanism that works for both. It pushes the bridge down, as well as our robot up when we cross the bump. And a little bit of linkage magic to minimize the work required by the robot (it just drives).

[Tom I]

My team opted for an arm of sorts (picture 2 arms connected so it's "one appendage" per the rules). This manipulator can lower the ramp, raise it for an alliance partner on the other side (or for an opponent for the final shared balance), and actually lift our front end to get our frame over the barrier, where the 6 wheel drive takes it. The arm has roller wheels (3" diam) to allow us to roll on the arm with it touching the ground. We also have a type of skid plate to prevent the bot from bottoming out on the barrier.

[legogeek24]

We're going with two pneumatic wheels and an angled chassis to launch over the bump. It's going to be super cool to watch and hopefully very effective!

[pyroslev]

Our frame's extruded aluminum (30x30 hand cut and welded). We toyed with a mechanized skid plate, treads, etc. In the end, one of the mentors and a student came up with the idea of putting angled braces on wither side of the front wheels.
Top view:
BBBBBBBRACE
Wheel
BBBBBBBRACE

Side view: (W=wheel)
Frame
WBrace
WBrace
WBrace
WBrace

The first wheel goes up, the skid braces hit and get you up then the rest of the 8 wheel drive takes over. Makes for a bumpy ride but in the end, it works. However you attach it, make sure they've got good welds/attachments and something like teflon on them to make things easier.

[Squillo]

Originally Posted by pyroslev

Our frame's extruded aluminum (30x30 hand cut and welded). We toyed with a mechanized skid plate, treads, etc. In the end, one of the mentors and a student came up with the idea of putting angled braces on wither side of the front wheels.
Top view:
BBBBBBBRACE
Wheel
BBBBBBBRACE

Yeah, that's what we did. At least I think it is - I couldn't figure out how to describe it, and you've at least made a stab at it. But we have the "braces" (VAGUELY like fenders; our plywood prototypes looked like fenders, but the final ones are just tubes of aluminum defining the outline of the 'fender') just on the outside of each wheel. They are made of tubular aluminum and the "braces" actually hit the bump before the wheel, lifting the (8" mecanum) wheel up a little so it can just slide over the bump. The chassis is high enough that it doesn't touch the bump in the middle. So we go over 2 wheels at a time (budump, budump). It works.

[Pun-isher]

We went with a higher riding drive this year, so a good amount of speed should do it.

Most teams will probably go with the pneumatic wheels from mcmaster, and maybe have a guide-rail system under their chassis. No need for moving parts when you have a moving bot

[Grim Tuesday]

Two words: Tank Treads.

[Squillo]

Originally Posted by Squillo

Yeah, that's what we did. At least I think it is - I couldn't figure out how to describe it, and you've at least made a stab at it. But we have the "braces" (VAGUELY like fenders; our plywood prototypes looked like fenders, but the final ones are just tubes of aluminum defining the outline of the 'fender') just on the outside of each wheel. They are made of tubular aluminum and the "braces" actually hit the bump before the wheel, lifting the (8" mecanum) wheel up a little so it can just slide over the bump. The chassis is high enough that it doesn't touch the bump in the middle. So we go over 2 wheels at a time (budump, budump). It works.

(emphasis added)

Update: I believe I spoke too soon. At this point, it does NOT work. At least, it does not work with our plywood 'bump'. It worked great when tested on our 'chassis-only' bot, but with the extra weight of the actual bot, no dice. We're still thinking it might work with the steel bump, but if not, no big deal, we can just zip over the bridge. And we're going to be so busy scooping up balls and scoring that it probably won't matter that much. We hope.