Question About Bumpers (R19, Specifically)

[bdaroz]

Originally Posted by mrnoble

... Sigh. Lose a year of bumper making and everyone's a rookie again.

That's ok, some of us rookies did a complete chassis redesign in week 4.

[mrnoble]

Originally Posted by bdaroz

That's ok, some of us rookies did a complete chassis redesign in week 4.

Some of us veterans did the same.

[m1tche11d]

Thanks for the quick replies, everybody! This will help clear some stuff up for our team.

[MrForbes]

I get the idea that the problem is that some folks have a different idea of what a "side" is. Or even what an "outside corner" is.

Until the GDC figures out a clear way to explain this, we're going to have trouble.

[Mark McLeod]

Watch the frame perimeter video that demonstrates how "sides" are defined: https://www.youtube.com/watch?v=VmSsky6-zc8

[Whippet]

Originally Posted by MrForbes

I get the idea that the problem is that some folks have a different idea of what a "side" is. Or even what an "outside corner" is.

Until the GDC figures out a clear way to explain this, we're going to have trouble.

I saw this suggested in another bumper thread somewhere, but I think it's worth repeating: an easy way to clarify this would be to rename "FRAME PERIMETER" to something more descriptive of what it actually is, like "CONVEX PERIMETER." That would help alleviate a lot of confusion regarding what constitutes a side of that perimeter.

[Richard Wallace]

Originally Posted by Whippet

CONVEX PERIMETER

I agree.

Al, will you take this suggestion up with the GDC?

[Cothron Theiss]

Thank you guys so much for this thread. We've always had normal, rectangular framed robots, so this is the first year we've ever needed to really understand the bumper rules. Aaaaand because of how we will have to change the bumpers, we're gonna have to redesign our intake and take the new one in to Competition. Oh well, least we're figuring this out now and not Thursday of the Regional.

[Sirdickey]

Originally Posted by bdaroz

That's ok, some of us rookies did a complete chassis redesign in week 4.

Some of us rookies ONLY had a chassis design by week 4.

[Captain_Kirch]

R:19 ROBOTS are required to use BUMPERS to protect all outside corners of the FRAME PERIMETER.
For adequate protection, at least 8 in. of BUMPER must be placed on each side of each outside corner (see Figure 4-3). If a side is shorter than 8 in., the entire side must be protected by BUMPER

R:19 answers the question in this thread, Why is this picture wrong. It also explains away the misconception "bumpers always have to be at least 8 inches."

The pictures is wrong because the corner isn't covered on BOTH SIDES. Plain and simple. The other bumper is flagged because it covers an interior corner, not an exterior corner and is "Not a bumper"

Do your bumpers extend at least 8 inches from each outside corner? Do they fully cover any side less than 8 inches? If the answers to these questions is yes, you don't have to worry about R19

[bjtheone]

Originally Posted by Captain_Kirch

R:19 answers the question in this thread, Why is this picture wrong. It also explains away the misconception "bumpers always have to be at least 8 inches."

The pictures is wrong because the corner isn't covered on BOTH SIDES. Plain and simple. The other bumper is flagged because it covers an interior corner, not an exterior corner and is "Not a bumper"

Do your bumpers extend at least 8 inches from each outside corner? Do they fully cover any side less than 8 inches? If the answers to these questions is yes, you don't have to worry about R19

As long as teams understand what constitutes a "side". R19 is defined in terms of outside corners but teams seem to struggle with this and focus on the "if a side is shorter than 8 inches..." part of the rule.

The biggest issue seems to be that a through the frame perimeter intake system on a robot does not create two short sides. It creates a design problem, in that you still have one long side (with a gap in it) and need to have 8" of bumper, extending inward from the outside corners, with the result that your side had better be 16" plus the width of your intake. Which is why over the bumper intakes are popular.

I do think that the pictures in Figure 4-3 do a good job of capturing this.