Low bumper question

I’ve read in a few places it is easy to drive onto a power cell ball and get it stuck under the robot. With the midfield boundary bumps, we’ve decided (so far) to go with 8" pneumatic wheels to reduce negative effects to the robot from repeated impacts. Using those wheels on the kitbot elevate the chassis higher than with the stock 6" traction wheels.

My question: The bumper zone is floor to [floor + 7.5"]. Bumpers are roughly 5" tall… a tad more. Let’s say the bottom of the chassis is ~2.5" above the floor instead of the usual ~1.5". I can’t find a rule that prevents the bumpers from being between 1" and 6" off the floor, even if that means there is ~0.5" between the top of the bumper and the top of the chassis (so some chassis is exposed above the bumper). Any problems with doing that? Thanks.

So long as your FRAME PERIMETER is within the BUMPER ZONE in your STARTING CONFIGURATION, you’re okay.

Remember that the bumpers must attach to the FRAME PERIMETER with “a rigid fastening system” (R24G) and the “BUMPER wood is properly supported to minimize the likelihood of breakage on impact. Flexible ROBOT elements, such as think plastic do not accomplish this intent and are not considered “structure/frame”.” (R26 Blue Box)

Judging from your obvious awareness of the rules around bumpers, you’ve probably already factored those considerations into your thinking… and so long as no part of the robot above the bumpers exceeds the frame perimeter established where you are connecting to the bumpers, and you are able to get solid mounting for the bumpers, I see no problems with what you propose.


And oft-overlooked fact, you have +/- .5" on the height of the bumper backing, so you could just increase the height to look nice on the frame. We’ve had some fun messing with that over the past few years.

Also remember you’re lifting your frame for the explicit purpose of getting easily over the midfield, make sure you don’t make it harder again because your bumpers are in the way. With your bumpers only 1" alone the floor,
and the midfield bump being 1" thers the possibility you will get your bumpers caught. Make sure you do testing. (As always :wink:)

One way to think of this: The frame perimeter is a some what a theoretical construct. By definition it is in the bumper zone (0-7.5 in). Anything above 7.5" is by definition not the frame perimeter. In starting configuration, the frame that is over 7.5" can be on but not over the frame perimeter.

Thanks all

The pneumatic wheels are mainly to soften impacts rather than elevate (though that’s a side effect), but yes we’ll test. It seems to me as long as the bottom of the bumper is slightly >1” when the front or back is tilted down (due to drop center), we should be safe.

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