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View Full Version : Bumpers w/pneumatic cylinders


Andrew Lawrence
11-28-2011, 10:16 PM
I've had this idea of placing pneumatic cylinders behind our bumpers (see below) for a few possible applications:

1. Shock absorbers: Add a bit of air to small cylinders, small enough to make only a small difference in bumper width from the robot, and use them as shock absorbers for collisions.

2. To use as a "defensive push": Basically, add the cylinders to the the bumpers, and when someone gets a little too close for comfort, we just launch out our bumpers. This could also be used to redirect another robot, or to assist in a pin.

What do you think? Is it legal?

11133

Duke461
11-28-2011, 10:20 PM
Someone will probably get a more technical definition soon, but im too lazy :rolleyes: .
The first thing you need to remember is that bumper rules change from year to year, so you can't rule out anything yet.
However, using the 2011 rules, I would say illegal, because there would in a sense be "gaps" in you robot. see here. (http://forums.usfirst.org/showthread.php?t=17471)
Hope this helps,
-duke

EDIT: This (http://www.usfirst.org/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2011_Assets/2011_FRC_Inspection_Checklist_RevD.pdf) should help a lot:

Andrew Lawrence
11-28-2011, 10:21 PM
Someone will probably get a more technical definition soon, but im too lazy :rolleyes: .
The first thing you need to remember is that bumper rules change from year to year, so you can't rule out anything yet.
However, using the 2011 rules, I would say illegal, because there would in a sense be "gaps" in you robot. see here. (http://forums.usfirst.org/showthread.php?t=17471)
Hope this helps,
-duke

And if you make it so the bumpers go over the gap length?

Duke461
11-28-2011, 10:24 PM
And if you make it so the bumpers go over the gap length?

Im not sure what you mean here, sorry.

EricH
11-28-2011, 10:26 PM
In past years, you'd be moving the bumpers off of the frame perimeter, or expanding the frame perimeter. This would result in gaps in the bumpers' coverage of the frame perimeter, or a violation of mounting rules.

In other words, if the rules don't change on mounting, you're going to be in trouble with the perimeter coverage rules. This is some of what Duke was getting at--<R07-A> in the 2011 rules.

Andrew Lawrence
11-28-2011, 10:27 PM
Im not sure what you mean here, sorry.

Me neither, but it's probably possible. I can think of a few ways, but they would be way too advanced. There are other, simpler ways, but I don't know. Just thinking, that's all. :p

Duke461
11-28-2011, 10:29 PM
Me neither, but it's probably possible. I can think of a few ways, but they would be way too advanced. There are other, simpler ways, but I don't know. Just thinking, that's all. :p

Yeah i definitely like the concept.
Maybe you could do what the dragonfly robot (http://www.chiefdelphi.com/forums/showthread.php?p=1071023) did, and then on top of that, those appendages could shoot out with pneumatics. That would be awesome.

Andrew Lawrence
11-28-2011, 10:36 PM
Yeah i definitely like the concept.
Maybe you could do what the dragonfly robot (http://www.chiefdelphi.com/forums/showthread.php?p=1071023) did, and then on top of that, those appendages could shoot out with pneumatics. That would be awesome.

I like that, but the goal is to avoid hitting opponents above the bumper line. That's why I had the bumpers move, for more bumper on bumper action, and less robot on other robot killing second robot and disqualifying first robot action, if you know what I mean.

Duke461
11-28-2011, 10:39 PM
I like that, but the goal is to avoid hitting opponents above the bumper line. That's why I had the bumpers move, for more bumper on bumper action, and less robot on other robot killing second robot and disqualifying first robot action, if you know what I mean.

They wouldn't hit above the bumper line. The bumpers, as 3553 did, would be on the ground flush with the real bumpers. Youd simply need some kind of linear slide on the appendages, and the pneumatics would shoot it straight out into the opponents bumper.

Andrew Lawrence
11-28-2011, 10:41 PM
They wouldn't hit above the bumper line. The bumpers, as 3553 did, would be on the ground flush with the real bumpers. Youd simply need some kind of linear slide on the appendages, and the pneumatics would shoot it straight out into the opponents bumper.

I see. I like that! Thanks! :D

EricH
11-28-2011, 10:52 PM
I would be VERY cautious with using a drop-down active bumper system. If someone tips over while it's active next to them, you're probably going to get warned, possibly carded and penalized. Also, bear in mind the expansion rules, and that you're putting extra weight in there that could probably be better spent elsewhere.

Just some things to keep in mind.

You *might* be able to pull your first option off within the rules, but the "rigid mounting" might get you, at least last year it would have.

Andrew Lawrence
11-28-2011, 10:57 PM
I probably should have said this at first, but unless the game next year and manuel give us a distinct advantage, I doubt I'll ever be using it. I just had the idea, and wanted CD's input. From what I'm hearing, the 1st option may be viable, so I'll test that on my own time.

Thanks everyone! :D

EricH
11-28-2011, 11:16 PM
I probably should have said this at first, but unless the game next year and manuel give us a distinct advantage, I doubt I'll ever be using it. I just had the idea, and wanted CD's input. From what I'm hearing, the 1st option may be viable, so I'll test that on my own time.

Thanks everyone! :D"Viable" is rather loosely used here, IMO. Under last year's rules, specifically <R07-K>, you'd also need to have the frame perimeter movable to have movable bumpers; that could make life rather "entertaining" with other stuff that needed to attach in that area. You'd also want to pay attention to the pneumatics rules.

Andrew Lawrence
11-28-2011, 11:19 PM
"Viable" is rather loosely used here, IMO. Under last year's rules, specifically <R07-K>, you'd also need to have the frame perimeter movable to have movable bumpers; that could make life rather "entertaining" with other stuff that needed to attach in that area. You'd also want to pay attention to the pneumatics rules.

Well, I do enjoy "entertaining"!

Peter Matteson
11-29-2011, 07:20 AM
From the 2011 FRC Manual
K. BUMPERS must attach to the FRAME PERIMETER of the ROBOT with a rigid fastening system to form a tight, robust connection to the main structure/frame (e.g. not attached with Velcro). The attachment system must be designed to withstand vigorous game play. All removable fasteners (e.g. bolts, locking pins, pip-pins, etc.) will be considered part of the BUMPERS.

A movable bumper in not rigidly mounted.

"Dragonfly" got around this rule because technically their additional drop down bumpers were non-functional decorations, not bumpers.

Peter Matteson
11-29-2011, 07:42 AM
I forgot to mention in the previous post 2 teams have made a system like this and used it for completely different reasons than you mentioned.

Wildstang used this design in 2006 to stabilize their wide body robot so it wouldn't tip when going up and down the ramp that year.

In 2007 Husky Brigade had a system like this so they could "point guard" and pass tubes to another robot across the floor.

It's important to note that bumpers were not mandatory back then and the rules for them didn't really start clamping down until 2008 when they were mandated to cover 2/3 of the frame perimeter.

Al Skierkiewicz
11-29-2011, 08:00 AM
Peter's reference to par K is right on. When Wildstang used this method in 2006 it was legal as the "frame perimeter" definition had not been written into the rules yet. Adding to the above...
<R14> When a ROBOT is in its STARTING CONFIGURATION, no part of the ROBOT shall extend outside the vertical projection of the FRAME PERIMETER (with the exception of minor protrusions such as bolt heads, fastener ends, rivets, etc).

Please be advised this is quoted from 2011 rules and may change for 2012.

JamesCH95
11-29-2011, 09:16 AM
In 1999 team 95 used a pneumatic bumper (aka "momentum transfer device") that worked VERY well in the days before bumpers. With pool noddle bumpers there isn't too much of an advantage to be had.

If you were going to use it to push opponents away... I can see two scenarios:

1) They have more grip than you, so you push yourself away from them.

2) You have more grip than them, so they couldn't push you around much in the first place.

A neat idea for sure, but I don't think it would be useful given the new bumper rules.

Andrew Schreiber
11-29-2011, 02:58 PM
"Dragonfly" got around this rule because technically their additional drop down bumpers were non-functional decorations, not bumpers.

They were not non-functional decorations. They were very functional parts of the robot and were treated the same way any other appendage that extended outside the bumper perimeter was.

Chris is me
11-29-2011, 03:22 PM
Articulated bumpers have been illegal for every year I've been in FRC. (2009 on) I wouldn't expect that to change.

They were not non-functional decorations. They were very functional parts of the robot and were treated the same way any other appendage that extended outside the bumper perimeter was.

Yup, those bumpers looked everything like BUMPERS but were there solely to reduce damage in contact outside the Bumper Zone. A non-BUMPER decoration?

AdamHeard
11-29-2011, 03:36 PM
In 1999 team 95 used a pneumatic bumper (aka "momentum transfer device") that worked VERY well in the days before bumpers. With pool noddle bumpers there isn't too much of an advantage to be had.

What does working very well mean?

JamesCH95
11-29-2011, 03:57 PM
What does working very well mean?

That year there was a puck on casters in the middle of the field, and our robot would run full-tilt into the puck with its bumper to knock it across the field.

The pneumatic bumper worked very well in that it inelastically transfered a good deal of momentum to the puck without damaging the robot or the puck.

It's been a long time (obviously) but I want to say the robot's top speed was 7-9ft/s, which was pretty quick back then. It was also a kiwi drive with all-aluminum machined wheels... but I digress.

Tristan Lall
11-29-2011, 04:10 PM
I sincerely hope that the re-worked robot rules will remove the need for questions like this surrounding bumpers.

All of the definitions (going back several years) that rely upon terms like "main structure" are inherently broken to varying degrees, because of the ambiguity of those terms. (What is "main"? The most important, the most massive, the first unit assembled, etc.? What if the entire frame containing the bumpers is articulated, but the bumpers themselves are not? And what's the point of reference for the articulation?) The bumpers should be defined in terms of functional specifications with wide tolerances, rather than requiring FIRST and its officials to invent definitions and interpretations that don't neatly apply to many potential robot designs.

Andrew Schreiber
11-29-2011, 04:14 PM
I sincerely hope that the re-worked robot rules will remove the need for questions like this surrounding bumpers.

All of the definitions (going back several years) that rely upon terms like "main structure" are inherently broken to varying degrees, because of the ambiguity of those terms. (What is "main"? The most important, the most massive, the first unit assembled, etc.? What if the entire frame containing the bumpers is articulated, but the bumpers themselves are not? And what's the point of reference for the articulation?) The bumpers should be defined in terms of functional specifications with wide tolerances, rather than requiring FIRST and its officials to invent definitions and interpretations that don't neatly apply to many potential robot designs.

Or worse yet, definitions which outlaw several potential robot designs that would have met the spirit of the rules but no longer are capable of meeting the letter. (Worse is when this happens after kickoff)