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Unread 01-20-2007, 09:35 PM
flamefixed flamefixed is offline
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Bottoming out on ramps?

Apparently ramps are going to be very common this year. With this said, what are your ideas on how to prevent your alliance robot from catching their chassis on the corner of the ramp (the transition from sloping ramp to platform parallel to the ground). Our robot may have a simple middle wheel on each side raised sightly above the drive wheels which will work on any degree ramp (as long as the front wheel can get to it). Though, not all teams may incorporate something to get similar results. I was thinking a roller at the transition, but this isnt as simple as one can say. So your ideas??

Thanks....
Steve
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Unread 01-20-2007, 09:37 PM
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Re: Bottoming out on ramps?

ours is going to be high enough off the ground to make it up a ramp. As long as it is not extremely steep, i am not sure of the exact degree.
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Unread 01-20-2007, 09:41 PM
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Re: Bottoming out on ramps?

16 degrees, give a take a degree.
I've just been reading how some are designing with a mere 2-3 inch ground clearance with a max climb angle of 14 or so.
Just want to make the bot is as universally adaptable and acceptable for everyones needs, 'cause you never really know what your going to get until your there.
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Unread 01-20-2007, 09:43 PM
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Re: Bottoming out on ramps?

We designed for a 30 degree ramp.
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Unread 01-20-2007, 09:45 PM
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Re: Bottoming out on ramps?

Isn't that going to be very difficult for teams with compromised traction such as teams with omni wheels or swerve drives?
It shouldn't be a problem for teams with six wheel tank drives or tracks.
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Unread 01-20-2007, 09:54 PM
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Re: Bottoming out on ramps?

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
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Unread 01-20-2007, 10:09 PM
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Re: Bottoming out on ramps?

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!).
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Unread 01-20-2007, 10:19 PM
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Re: Bottoming out on ramps?

Quote:
Originally Posted by flamefixed View Post
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.
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Unread 01-20-2007, 10:22 PM
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Re: Bottoming out on ramps?

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.
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Unread 01-21-2007, 09:22 AM
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Re: Bottoming out on ramps?

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.
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Unread 01-21-2007, 09:25 AM
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Re: Bottoming out on ramps?

we did a quick angle calculation last night, 11.5 degrees, but that is caused by some interesting geometry considerations in our tenative design.
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Unread 01-21-2007, 09:45 AM
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Re: Bottoming out on ramps?

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
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Unread 01-21-2007, 10:46 AM
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Re: Bottoming out on ramps?

This reply is for rockahawk. If you were here, you would know that we have a1 1/2 clearance to the frame and the ramp is 17.13 deg. Whick is not less than 17. Knucklehead.
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Unread 01-21-2007, 11:18 AM
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Re: Bottoming out on ramps?

Our ramp(s) wont have a "peak" or transition to go over....think about that!
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Unread 01-21-2007, 12:45 PM
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Re: Bottoming out on ramps?

Quote:
Originally Posted by PVCMike View Post
Our ramp(s) wont have a "peak" or transition to go over....think about that!
That's what I was thinking...
Why not use a curved ramp? A transitional ramp with an intermediate slope between the ramp and platform? Both would reduce the corner and make the transition easier.
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