Al's Annual Inspection Thread

[Siri]

Originally Posted by Al Skierkiewicz

Siri,
You can secure the surgical tubing to itself (after you have wrapped the tubing around a structural part of your robot) using ty-wraps as there is very little load on the ty-wrap when the tubing is in motion. You don't want to use them in place of hardware (as a tie bar or link) to secure one end to a stationary part of your robot. The dynamic loads could cause them to fail.

Thanks, Al. Understood; this is the way we use them.

[tag_groff]

Originally Posted by BBray_T1296

Spontaneous Deconstruction can plague any type of shooter. Elastic or electric or pneumatic

I prefer Rapid Unplanned Disassembly.

[wireties]

We just finished the Dallas Regional and the robot on robot contact was pretty rough. We are thinking of adding some strength in the bumpers. Can the CD community help us understand on the limits and intentions of R21? We know we need to query the GDC but I'm not sure how to phrase the query (yet).

So the angle to hold the cloth must be aluminum, correct? No steel? But we could use 7071 or 7075?

Can we interconnect the top and bottom angle pieces? We know many top tier teams do this. But is it contrary to the rules? I'm thinking a solid 5"x1"x<length> u-channel is problematic for an inspector. But perhaps if there are just some small finite number of inter-connections between the top and bottom angle that might be OK. So my last query is how much structure can there be between the top and bottom angles before it causes inspection problems.

TIA

[AllenGregoryIV]

Originally Posted by wireties

We just finished the Dallas Regional and the robot on robot contact was pretty rough. We are thinking of adding some strength in the bumpers. Can the CD community help us understand on the limits and intentions of R21? We know we need to query the GDC but I'm not sure how to phrase the query (yet).

So the angle to hold the cloth must be aluminum, correct? No steel? But we could use 7071 or 7075?

Can we interconnect the top and bottom angle pieces? We know many top tier teams do this. But is it contrary to the rules? I'm thinking a solid 5"x1"x<length> u-channel is problematic for an inspector. But perhaps if there are just some small finite number of inter-connections between the top and bottom angle that might be OK. So my last query is how much structure can there be between the top and bottom angles before it causes inspection problems.

TIA

Most of what you see behind the bumper is consider part of the mounting system for teams. Texas Torque and my team both used sheetmetal parts as part of our bumper assemblies this year that become part of the mounting system for the bumpers. Torque's are an entire c channel like you describe. We use a z- bend on our top rail and normal 1" angle on the bottom.

[Jon Stratis]

Originally Posted by wireties

We just finished the Dallas Regional and the robot on robot contact was pretty rough. We are thinking of adding some strength in the bumpers. Can the CD community help us understand on the limits and intentions of R21? We know we need to query the GDC but I'm not sure how to phrase the query (yet).

So the angle to hold the cloth must be aluminum, correct? No steel? But we could use 7071 or 7075?

Can we interconnect the top and bottom angle pieces? We know many top tier teams do this. But is it contrary to the rules? I'm thinking a solid 5"x1"x<length> u-channel is problematic for an inspector. But perhaps if there are just some small finite number of inter-connections between the top and bottom angle that might be OK. So my last query is how much structure can there be between the top and bottom angles before it causes inspection problems.

TIA

Per the rules, "structure" between the top and bottom angle isn't allowed. HOWEVER, you can do pretty much whatever you want in terms of mounting (within all other applicable rules). If your bumper mount included a 5"x1" U channel that covered the entire back of the bumper, I don't think I would have a problem with it, provided it met all the other rules (specifically weight, 1" limit on hard parts and backing requirements come to mind).

[Al Skierkiewicz]

Jon,
As I understand the description, this is a legal implementation. The angles are optional but the ruling has been that as long as the "hard parts" definition is not violated and the bumper system remains under 20 lbs., sheet metal is acceptable. I expect to see more of this type of design as the season progresses due to the intense contact inflicted in this game.

Teams, please remember...

3.2.6.2 G28
Deliberate or damaging contact with an opponent ROBOT on or inside its FRAME PERIMETER is not allowed.
Violation: TECHNICAL FOUL
High speed accidental collisions may occur during the MATCH and are expected.
ROBOTS extend elements outside of the FRAME PERIMETER at their own risk; no
penalties will be assigned for contact between two such extended elements.
A ROBOT with an element outside its FRAME PERIMETER may be penalized under this
rule if it appears they are using that element to purposefully contact another ROBOT
inside its FRAME PERIMETER. Regardless of intent, a ROBOT with an element outside
its FRAME PERIMETER that causes damage to another ROBOT inside of its FRAME
PERIMETER will be penalized.

[Al Skierkiewicz]

My previous post has triggered my reminder for today.
If your robot design has elements that extend outside the frame perimeter, (i.e. hammers, kickers, leg lamps, etc.) your inspector should remind you that you are responsible for that element coming in contact with or inside another robot Frame Perimeter. If you are using a hammer or kicker, you have to be careful as to when to deploy the mechanism. A robot standing behind your robot may be contacted in such a manner.
Anyone who has watched any match videos has seen that bumpers are taking a beating. Many teams are finding they are receiving a disable when their bumper(s) get torn off in the hard hits that come with this game. When your inspector points out to you that your bumpers may meet the intent of the bumper rules but will not likely survive the game, please take their advice. A few screws will not meet the "robust connection to the main structure/frame" in this game. Remember that "lift" test mentioned earlier? Even passing that test may not be enough to determine the survivability of your bumper system. My team has added additional structure behind the bumpers.

[philso]

Originally Posted by Jon Stratis

Per the rules, "structure" between the top and bottom angle isn't allowed.

Where does this appear in the rules? I have looked in the Game Manual, the Team Updates and the Q&A.

Originally Posted by Al Skierkiewicz

sheet metal is acceptable

We were using hinges at each corner to connect the various bumper sections together (front, sides, back) but they got pretty mangled due to repeated heavy impacts. Would it be acceptable replace the hinges with aluminum sheet formed into L-shaped corner brackets that extends 6-8 inches (or more) along each side/front/back? Multiple screws would be used to attach each bumper section to each corner bracket. The corner brackets would be sandwiched between the bumpers and the chassis. The bumpers would be attached to the chassis using aluminum angles screwed into the bumpers (and sheet metal brackets) and 1/4-20 bolts into the chassis. Some of our bumper sections are too short to have more than one point of attachment to the chassis. The corner brackets would transfer a lot of the forces to the neighboring bumper sections.

[Al Skierkiewicz]

philso,
I obviously cannot make an interpretation based on a description, that would be for your inspector to decide and of course for the Q&A to answer if it is something that hasn't been seen in the past. In general, bumpers using an angle to secure the corners has been allowed in the past. This is provided all other bumper rules are in compliance (the 1/4" gap rule and support in the corners for instance). As always, bumper construction is examined for weight, specifically for the maximum, and for any weight that should be correctly attributed to the robot weight.
Please remember that even if you have reversible bumper covers, the removal by one person in fifteen minute guideline still applies. We don't want you to miss a match because we need to accurately weigh your robot for some reason, only to find out it takes 30 minutes to get the bumpers off. I have seen one robot this season already that riveted their bumper system on to the robot frame thinking they would never have to remove them. That became very evident when the bumper fabric got ripped off in their second practice match.

[Bruceb]

we were at Superior a couple weeks ago and I can tell you that there were NO penalties called for inside the frame perimeter contact. We have a lot of damage on parts that are well inside the frame perimeter so build them strong folks!!!!

[pfreivald]

Originally Posted by Bruceb

we were at Superior a couple weeks ago and I can tell you that there were NO penalties called for inside the frame perimeter contact. We have a lot of damage on parts that are well inside the frame perimeter so build them strong folks!!!!

Yet at Tech Valley there were many many many!

[philso]

Originally Posted by Al Skierkiewicz

philso,
I obviously cannot make an interpretation based on a description, that would be for your inspector to decide and of course for the Q&A to answer if it is something that hasn't been seen in the past. In general, bumpers using an angle to secure the corners has been allowed in the past. This is provided all other bumper rules are in compliance (the 1/4" gap rule and support in the corners for instance). As always, bumper construction is examined for weight, specifically for the maximum, and for any weight that should be correctly attributed to the robot weight.
Please remember that even if you have reversible bumper covers, the removal by one person in fifteen minute guideline still applies. We don't want you to miss a match because we need to accurately weigh your robot for some reason, only to find out it takes 30 minutes to get the bumpers off. I have seen one robot this season already that riveted their bumper system on to the robot frame thinking they would never have to remove them. That became very evident when the bumper fabric got ripped off in their second practice match.

Thanks for your feedback, Al.

At this time, I have no photos to show since I am trying to do my homework in case it is decided to replace our current bumpers with ones that will hold up to the abuse better. We would not want to put the time and effort into building something that has no hope of passing inspection. I would like to use corner brackets that extend at least 6" from the corners to resist the twisting we are getting because the contact with the frame is made in the lower 1 1/2" of the bumper. We will be using our current scheme to install and remove the bumpers. It takes about 2 minutes to swap between the two.

My main concern is that the corner brackets I am proposing would essentially cover the whole inside vertical surface of the bumpers, extending from the bottom to the top (5" high) and all the way around. The bumpers would end up consisting of an 1/8' thick layer of aluminum on the inside, 3/4" plywood, then the pool noodles on the outside. There would not be any gap between the aluminum and the plywood. The cloth covering would be trapped between the aluminum and the plywood. It would be the 1/8" aluminum plate that would contact the frame instead of the plywood. Does this sound like something that would be accepted at inspection?

Thanks.

Phil

[Al Skierkiewicz]

Phil,
This was asked on the LRI telephone conference last night. It sounds like you are planning a legal implementation, again providing all bumper rules are met. I reminded LRIs that the 1" hard parts restriction still applies, so consider that as well. The 1" extends out from the Frame Perimeter, not the back of the bumper. So if your mod is affected by hardware or other protrusions on the frame, it may not pass inspection.

[philso]

Thanks again for your help, Al.

I studied the Game Manual, Team Updates and Q&A, several times before working this out and will be watching out for the items in your comments. I had not seen any teams putting sheet metal between the bumper wood and the frame so I wanted to make sure we weren't going to go down the wrong path.

Phil

[Al Skierkiewicz]

Phil,
Many teams have done this for many years. WildStang is trying the same idea this year.