Bumper height v. height of "the bump"

FIRST General Forum
1

Assuming I read and understand everything correctly:

Robot bumpers ought to be 5" tall, and must sit between the bumper zone of 10" - 16" from the floor. So bumpers would ride at their lowest from 10" - 15" from the floor and their highest at 11" - 16" from the floor.

“The bump” starts it’s angle at the floor and tops/levels off at 12" from the floor.

So isn’t it the case that everyone’s bumpers will actually be higher than “the bump”? Significantly high on the top anyways? The robots in the demo video don’t seem to be designed this way, although I 100% understand that video is just to get the idea across… for reference.

Since the wheels cannot extend outside of the bumpers, this is creating a funny picture in my head of a robot trying to successfully climb over “the bump”… I always sucked at math, so I guess the angle of the actual “bump”, floor to top, is well designed to allow robots to climb it without having their bumpers get in the way. I dunno… I can’t wait to get a practice bump built so I can see this first-hand.

Does anyone know the angle of the “bump” sides, floor to top?

2

as far as i know the bumps are 3 feet wide at the bottom and 1 foot wide at the top so that would give them an angle of 45 degrees.

3

45 degree slope, with a 1/2" transition from the carpet to the start of the bump slope.

4

Remember, the bottom of the bump is as wide as the platform. I don’t remember all the numbers so I can’t give you an exact number, but the top of the bump is 12 in and te height is 12 in. You can find the angle easily with a little trig.

5

I guess I was a bit thrown off by the thing, visually. 45 degrees makes near-perfect sense.

With the wheels being larger and bumpers being higher, I imagine robots would have no trouble, on paper anyways, driving up a grade such as this.

6

I’m surprised no one pointed this out, but the whole first part of my original post was BS. The tunnel is 18" tall, it would seem, and the top of “the bump” is actually about 20" tall from the floor.

SO. The top of the “bump” should indeed be taller than the bumpers on any robot.

This sorta doesn’t make sense because shorter robots might not be able to see over the bumps in this case, correct?

7

You were right the first time - the top of the bump is 12" of the ground, with a 45 degree slope. The platform - the deck of the tower - is 20" off the ground.

You are right that most of the bumper will be higher than the bump. I used a 2D CAD sketch, with a bump and robot with bumpers, to analyze this issue - if you can also, that’d be great!

I discovered that if you build the bumpers at 10" (the lowest extreme) that you can use a tire size smaller than 16" to climb the bump. Surprisingly, tires larger than 16" will hit the bump with their bumpers first, rather than the tire. So, as long as you a tire smaller than 16", about as far forward as you can possibly design them, you should be perfectly fine getting up the incline of the ramp.

I do recommend doing this analysis yourself, if possible, because a robot with 4" tires - smaller than I think anyone would use - actually would need to have 10" of ground clearance to avoid “bottoming-out” on the crest of the bump.

If you have any questions, feel free to ask. Good luck to you and your team!

8

Here is a drawing I made of the bump… If your not careful a robot could put their bumper right on top of the other robots bumper and be lifted when going up the ramp.