Bumper Update

Hello!
I’m wondering if any other teams are having trouble with the bumper update (eight inches on each side, etc.) I expected there to be more concern over this, or is everyone too busy?

Just so you’re aware… The rule has been in there since Kickoff (and, in past seasons with bumpers and identical wording, it’s been the same thing, and tripped up a lot of people). Diagrams are meant to aid in understanding of the rules. And… there are a lot of teams that have asked questions about it. So, yes, I think a lot of teams are having trouble. Mine isn’t–but that’s because we’re doing a full-perimeter bumper setup.

What questions and concerns do you have specifically?

The 8 inches on each side rule has been the same rule since 2012 (not including 2015). It was not a surprise that the rule was included. The bumper rules are very similar to what we had in 2012-2014 too, other then the bumper zone, which isn’t a huge change.

We’re trying to fit in an indent to our perimeter to allow the boulder to roll in, however both sides of the gap would need 8 in of bumper, which is a design we haven’t tried yet. And this extra 16 inches to the front would go over the 120 perimeter limit.

It’s doable–a 26" x 34" robot can have enough room for a boulder to roll in. (For some reason, many teams prefer slightly wider than that.) Unless you really have a long, narrow robot planned…

Now, that being said, there ARE other tricks you can try. Might be time to take a look at some of the 2012 intakes–I think 16, 67, and 330’s intakes from that year will provide some insight. It’s entirely possible to pick up a Boulder with a full bumper. Also, you could look at how wide your intake slot would be if you had your bumpers at maximum height–maybe there’s a couple of extra inches there.

We went back to another team’s successful design from 2012 to try a little experiment…

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we suspected that the rule would be enforced this way. Fortunately we figured this out early enough to design around it.

I’m sure plenty of teams are doing a through-bumper intake, including my own. How you adapt your perimeter and design depends on your strategic objectives and current plans to fulfill such objectives. If we could get specifics, we can better help.

If all else fails, find a way to do an over the bumper intake, like several of the robots in 2012.

Best to know this now than at the inspection table at the competition!

I’m curious about this comment. You do know that the bumpers are not included when you are measuring the frame perimeter?

We know that, however the bumper must be supported by eight inches on each side.

I think you’re confusing “length of metal in my robot’s frame” with Frame Perimeter.

And I REALLY hope I’m right, because that could catch you.

So, here’s my question to you: If you stretch a string around your robot right now, in the bumper zone, is it 120" or less? And, how wide is the gap currently? (And the side length, if you don’t mind.)

Also, one other suggestion: read the rules on “support” of bumpers again.

Okay, so the gap for the ball is 10-12 inches, right? And the rules state that there must be 8 inches on either side of the opening from the corner out, like figure 4-3, bottom left robot. So 10+8+8=26, which is a lot. And that would not work for our previous diagram for our robot.

Though we’re playing around with the idea of an arm/sucker combo with wheels to suck up the ball and the arm to aim.

Your math is correct. If you want to bring the ball in, through the bumpers, at the balls widest point then you need at least 26" (10"+8"+8") of frame perimeter on that side.

I didn’t ask for how it would affect you. I asked for the NOW dimension. Read: As your robot sits right now, in CAD or in “person”, is it <= 120"? And what exactly are you working with for dimensions? There may be ways to adjust to be able to use a gap.

BTW, 26" is actually a rather narrow robot, even under frame perimeter being the dimensional driver. Many teams will build more “square” robots.

Hm… I’d have to talk with the lead CADer…

It was 21" x 35".

Which, for the front to have the necessary width, we’d have to add 5 inches. 26 x 35 would = 122 (greater than 120), so if we take 2 inches from the back, we’d have 26 x 33 = 118 (which would fit).

And it’d be square…

However, trying to fit a 10" ball into a 10" hole would be practically impossible, so bump the hole up to 12", take 2 away from length, which would be 31 x 28 = 118. However, add 6 inches of bumper, and it wouldn’t fit into the batter near the tower, making the low goal/climbing practically impossible.

And that’s why we aren’t going in that direction. Sorry for the miscommunication.

Ah, that makes more sense.

I’d definitely go over-bumper in that case. 10" ball, 15" to work with-3.25" for bumper width, so there’s about an inch to play with on the far side of the ball. You could also leave a gap in the bumper to help center the ball going over. You’d have about 5" of gap available if you opted to use it, which could also make it possible for a full-height bumper to let the ball go under. (Haven’t measured a ball to check.)

Decisions, decisions… seems like some prototyping might be in order.

see the video link in my post above. you don’t need a gap to get a ball under the bumper, if the bumper is at the top of the BUMPER ZONE. that’s one of the very first things I wanted to test when I saw the game…

Yes, your math is correct (what did you mean by “square”). We are planning a 31 long x 28 wide (plus an 1/8 for sheathing for 118.5" perimeter). The longer wheel base has a shallower tilt angle as it goes over the defenses (less tippy) and as you noted has a better chance of getting on the batter.

Why do you think the 28" + 6" side wont fit against the tower on the batter? Is your 28" the width or length?

By square I mean rectangular.

31 wide 28 long, though we’re working now with more of a trapezoid shape, with angled sides. I’m not entirely sure why this design wouldn’t fit onto the batter. Maybe it’d get stuck on the large, angled surface?

double check the space between the dividers on the batter. I did not find a dimension, but they look to be 2’6" close to the tower - which will fit a 28" wide robot (assuming bumpers higher than divider) up against the tower, but not a 31". If you dont plan on scaling the tower, it may not matter.