Bottoming out on ramps?

[flamefixed]

Exactly. It will be hard, but ive worked up a pretty much slip resistant design for the ramps, its just that transition which we are all pretty stumped on

[Scott358]

This is a very intersting point, especially as it relates to climbing 12" high ramps.

We're designing with 4" ground cleareance (in the center), which allows for a ramp as steep and high as last year (which happened to be 12" high). I forget the angle, but I believe it's a bit more than 30 degrees.

In the end, regardless of how you do it (ground clearance, skid pad, 6 wheel drive, etc...), you definately want to keep ramp climbing in mind (assuming you're not the ramp!).

[1768]

Originally Posted by Scott358

In the end, regardless of how you do it (ground clearance, skid pad, 6 wheel drive, etc...), you definately want to keep ramp climbing in mind (assuming you're not the ramp!).

Given the abundance of ramps, keep ramp climbing in mind even if you ARE the ramp. e expect to be on at least one team where the entire team is ramp-bots, so we are designing to climb a ramp and be a ramp low-clearance bots can climb.

[MrForbes]

Originally Posted by flamefixed

Exactly. It will be hard, but ive worked up a pretty much slip resistant design for the ramps, its just that transition which we are all pretty stumped on

There are some things you can do...the ramp can have a rounded or multi-angle transistion. Part of the platform could sit higher than 12", to make it easier to get on, and still keep the angled part of the ramp kind of short. Some commercially available motorcycle ramps are rounded near the top to ease the transition, see if you could copy the design.

[K.Porter]

We've designed a 4 wheel drive system which is very much centered at the front of the robot, with the back being supported by casters. That way, even if we do bottom out we will be able to drag ourselves up a ramp with the front wheel drive.

As for our ramp, we have allowed for a shallower angle than last year's playing field, and we hope to round the top corner.

[rocknthehawk]

Right now, our ramp is just under 17 degrees. Our 2005 bot had 2 inches of ground clearance and it seems to be able to climb it fine. We may change the design, so the angle will be closer to 13 or 14.

[MrForbes]

we did a quick angle calculation last night, 11.5 degrees, but that is caused by some interesting geometry considerations in our tenative design.

[T3_1565]

our robot is fairly low clearance, probably not enough you climb a ramp, but like perviously said we should be able to drag ourselves up with our front wheel drive, we are going to be lifting most of the time anyways, so maybe we wont have to

[Curt Henderson]

Originally Posted by K.Porter

We've designed a 4 wheel drive system which is very much centered at the front of the robot, with the back being supported by casters. That way, even if we do bottom out we will be able to drag ourselves up a ramp with the front wheel drive.

As for our ramp, we have allowed for a shallower angle than last year's playing field, and we hope to round the top corner.

If I understand your idea correctly, it should work if the center of gravity of your robot is balanced over your drive wheels to maintain contact with the top ramp surface. Otherwise you may find yourselves grounded on the ramp with your drive wheels in the air as the CG of your robots shifts to the back wheels when you go up the ramp.

Should this happen, you can always go up the ramp in reverse.

Good Luck!