pic: What happens when you get hit



After looking over our robot after champs this year we realized that we were hit harder than expected during our second to last match.

What’s with the “do not tighten?”

Was that area covered by bumpers, and if so, what happened to the bumpers?

Looks like it’s a cover for a sensor of some sort (lidar?). Don’t wanna squish those!

To maximize hopper space we put our turret on rails that it could be slid out on at the beginnning of the match to sit out over our bumpers, the geometry didn’t turn out exactly square, so one of the corners of the rails had to sit loose to allow side to side movement as the turret slides out.

Our bumpers were there, though that is were the two bumpers meet, could have been the reason that is the area we are seeing the deformation due to all of the load being centered to that point.

This is where that precision alignment tool comes in handy :wink:

Our team also encountered this same issue. The damage was severe enough that we had to put a welded steel bar and plate in the front of our robot to reinforce the frame.
Image of the damage: https://drive.google.com/open?id=0B07a4iJr7JrLbHRfZk92d3pQU00

We played defense quite a bit and got a huge dent in our front plate at some point. For us it was right next to our climber, where there are no bumpers.

obligatory grumbling from someone who was around before bumpers

Those hits just keep getting harder now that the padding has arrived. To paraphrase one of my (formerly) rugby-playing friends’ shirts:

“FRC is nice these days, but the bumpers dull the pain.”

We had a similar experience albeit in our first match of the season.

http://i.imgur.com/i7Po1Akm.jpg

Is that .0625’’ tubing on your main drive chassis?

We’ve found that using that is a bad idea, for basically that exact reason. Our main robot frame is usually .125’’.

Agreed.

I know you were talking about Isonine’s robot, but my robot is 1/8" wall tube or plate everywhere, or thicker.

+1

Do you feel that perhaps your weight savings measures down in that area could have been a bit too aggressive? I’m no mechanical designer, but that looks like quite a bit of material removal.

Also, we weld (or gusset and rivet, for our practice robot) vertical 1" square pieces of tubing to tie our upper frame to our lower frame. I do believe that helps in localizing damage from any one particular hit.

After a season where we were no stranger to bumper-to-bumper contact, I think the right front side of our frame was slightly dented in, but it has not caused any functional concerns.

Is the damage to 401 and 2619’s robots only from robot-to-robot contact or is some of it due to robot-to-gear carriage contact?

You should avoid using 0.125 in the superstructure unless it REALLY needs it. 1678 only uses the stuff in the drivetrain with very few exceptions. Try 0.090"(all our gussets) and 0.063" for your plate parts, we only use thicker if it’s part of a gearbox.

This is good for the internals of the robot. For things that support anything which goes outside of the robot on a regular basis, either deforming material or thicker aluminum is needed. Yet a good rule of thumb is that there shouldn’t be anything outside of the robot bumper and in the bumper zone on a regular basis unless it can take a beating.

Due to the jibber-jabber from 48, we spot-welded an “I beam” of dual 0.75" C-Channels down the length our thick wall intake arms. While the match against 48 was a bit dull, we did wind up with a huge blindsided hit from 610* with the intake out, and it survived with no bending. Next year we will try to keep it all inside the frame ::ouch:: .

*Both at near full speed, they were totally blind behind the airship and we didn’t see them cutting across. Whoops.

I thought you guys were using 1/16 for your front rails? Or is that more of a “yeah we probably won’t do it again” response?

Good advice. Although I was sad no one accepted my invitation to visit our exposed gear intake.

Due to the jibber-jabber from 48, we spot-welded an “I beam” of dual 0.75" C-Channels down the length our thick wall intake arms. While the match against 48 was a bit dull, we did wind up with a huge blindsided hit from 610* with the intake out, and it survived with no bending. Next year we will try to keep it all inside the frame ::ouch:: .

Was that “jibber-jabber” from us (i.e. me), or from gullible fraidy-cats drumming up ghosts of 2007? ::safety:: Regardless, I’m glad something we said caused you to reinforce an exposed mechanism. Perhaps that accidental hit from 610 would have caused more damage had it not been there.