Our team would like to know if it would be against the rules to use a flat hose as an air bladder for our lifting mechanism.
Thanks.
It would be a pneumatic component. It would also not be one of the specifically allowed items in <R72>. Therefore, it would be illegal under <R71>.
What makes this considered to be a pneumatic component?
Pressurized air. At least, if you’re using it to hold air, or cause movement with air, it’s pneumatic.
Thank You.
Thanks Eric,
I’d like to ask a follow up question.
What if the hose and connectors were rated at 125 psi, and it was a COTS item, generally available to other teams.
Are there other characteristics that would make it illegal?
Given that it was COTS rated to 125 PSI, I’d look at the following Q&A:
http://forums.usfirst.org/showthread.php?t=13703
http://forums.usfirst.org/showthread.php?t=14242 << Especially this one…
If you can’t answer it that way, ask it to Q&A and see what they think.
Not sure either of those help me, or maybe it is my ability to read the rules, I don’t know. Could be the six week zombie syndrom 
Anyway, if the hose is considered a pneumatic cylinder, then why is it not permitted under <R72>D
In addition to the pneumatic cylinders provided in the KOP and the “free” pneumatic
cylinders available for order through the Free Pneumatic Components Order Form,
additional air cylinders or rotary actuators may be used. Cylinders may be of any
configuration, and may be of any size up to a maximum of 24-inch stroke and 2-inch
diameter.
If the hose is considered a storage cylinder then it is excluded under <R72>A:
One or two additional Clippard air storage tanks (Clippard Part Number AVT-32-16),
equivalent to those provided in the kit. This means that up to four, and no more, Clippard air
storage tanks can be used on the ROBOT.
I will submit to the GDC Q&A once I figure out if I can get the hose I need. Thanks for your input
The second one refers to a diaphragm, or flexible membrane, to convert air force into mechanical force. I think this the type of device that you’re asking about. The GDC has specifically pointed to that as not legal.
There was one–in fact, the first one in the pneumatics–about using inflatable items. However, it doesn’t cover inflatables that are inflated using the compressor’s air.
http://forums.usfirst.org/showthread.php?t=13703
You might reference it when you ask, something to the effect of, “Regarding [previous link], does the answer change if the inflatable item is COTS, pressure rated to at least 125 PSI, and inflated using the onboard FRC pneumatics system? If not, which rule does it violate?”
Richard,
The two Q&A answers do cover your question. The GDC’s response is related to devices that produce movement. The hose expansion produces movement by the introduction of air pressure. The only devices that may do that are defined in R72 as cylinders up to a specific size and rotary actuators.
The last paragraph of section 8.3 gives you a little statement from the GDC that might help.
“In addition, another intent of these rules is to have all energy sources and active actuation systems on the ROBOT (e.g. batteries, compressors, motors, servos, cylinders, and their controllers) drawn from a well-defined set of options. This is to ensure that all teams have access to the same actuation resources, and to ensure that the inspectors are able to accurately assess the legality of a given part.”
I see that the explanation of what we are intending to do is not clear.
We are thinking of putting a hook on the end of a flexible tube/hose that is deflated. We would inflate the hose with air from the accumulator(s) which would raise the hook to the point we could grab the bar. Then we would use a winch to lift the robot, probably deflating the tube once the hook is on the bar.
So there is no piston in the hose.
I’m still unclear whether the hose would be considered a cylinder or accumulator. It’s intended use is closer to that of a cylinder.
Based on Al’s last comment about the last para. of 8.3 it looks like the intent of the rules is to have a well-defined set of energy sources/actuation systems would probably exclude what we are thinking of doing, but…
…once we get specifics on the hose and fittings, I’ll submit the question to the GDC for a final ruling.
Someone wanted to do the same thing with PVC. GDC said no. http://forums.usfirst.org/showthread.php?t=14194
I don’t think PVC is rated at 125psi. The hose I am looking at is rated at 125psi by the manufacturer, including fittings. The hose could be custom made so no modifications need to be done.
Yeah, that’s a bit tricky to call. Q&A it; if it’s good for you, I’ll try to remember to grab a digital copy of the Q&A in case you guys forget to do so. You’ll be at Arizona, right?
Would coiling up a thin (like 1/16" or 3/32") strip of polycarbonate with the hook at the end and a servo/pneumatic release pin work?
We have tried other things, didn’t know you could get polycarb to coil like that. Certainly worth a look.
The students on both teams I am working with are pretty stubborn about trying to make the air filled hose work, but may have to go with an alternative as time is running out.
Eric,
2493 will be in San Diego, 3295 will be in LA. I will be in Phoenix but not the team.
Richard,
I would be interested in knowing some more about this hose. You can PM me with reference if you wish.
I’m not 100% sure the miracle hose exists yet. One of the team members is going to http://www.hose-man.com/sys-tmpl/colton/ to check it out today.
The site allows you to select characteristics of the hose. The on site visit should confirm what they can do for us, how flexible the hose will be, how much it will cost, if 60psi or less can make it stand erect, etc.
As soon as I get details, I will post it.
OK, generally a non-flex hose under pressure is not a desirable effect.
Here is the question as posted on the Q&A
We would like to use a discharge hose, inflated using the onboard FRC pneumatics system, to raise a hook and cable to grasp the tower for elevating our robot.
The hose would remain folded or coiled on the robot until it was inflated to lift the hook.
Once the hook is set on the tower, the hose would deflate and a winch system would be used to raise the robot.
We have found a supplier that will supply the hose at any length we want (probably 5-7 ft), less than 2" in diameter (it will be either 1.5 or 2 inches) with caps at either end of the hose, with one cap having a threaded hole that will fit the pneumatic connectors that come with the KOP and screw into the Bimba cylinders. The hose will be rated by the supplier at 150psi. It is a flexible vinyl type of hose. The supplier will build the hose to our specifications so no further modifications will be done other than to attach a hook to one end of the hose and a pneumatic fitting to the other end. The end with the pneumatic fitting will be securely mounted on the robot.
The web site for the supplier is The Hose-Man: http://www.hose-man.com/sys-tmpl/door/
We anticipate filling the hose with no more than 10psi, more likely we will be using 5psi, depending on the amount of weight we are lifting. A pressure regulator will be used to control the amount of pressure in the hose.
o We are not intending to use the hose as an air storage system (<R01>B)(<R72>A)
o We think this should be permitted based on <R27>D as an additional air cylinder. There is no piston, so the stroke is under 24 inches and the diameter will be 2 inches or less.
o The hose will be filled with the onboard FRC Pneumatic system so it does not fall into the category of this previous Q&A posting: http://forums.usfirst.org/showthread.php?t=13703Would this type of system be legal? If not, which rule would it violate?
Thank you for your time
Now to wait for the answer…