Pneumatic Muscle

[Superllama12]

Anyone else interested in the pneumatic muscle? I, personally, think that it is really cool, and we will definitely be using it on our robot!

[Bill_B]

I'm intrigued too. Trouble is there is not really enough pneumatic savvy on our team . . . yet!

[Nemisis]

Our team likes them but noticed that they aren't the way to go if your looking for the piston to have speed. Especially with the air pressure limit... however we have noticed that the availability of torque is amazing!

[Navid Shafa]

Originally Posted by Superllama12

I, personally, think that it is really cool,

I definitely agree. I like the smoothness of operation, but the difficulty to control and or program, along with complexity makes me lean more towards lifts and arms. The pegs are at set heights, and the advantage of indexed values makes the drive team's job a lot easier. "Push a button, activate lift and raise to set height, drive forward, score" It's always a tradeoff... I wish you luck!

[JohnHorton]

I'm also really interested in PAMs, but the control issues, and the availability, might make it hard for teams to use. That being said, I'd love to see a manipulator using these with the manual dexterity of a human hand.

[JesseK]

In reading the specs for the muscle, we determined that we weren't capable enough to fully ensure alignment during the 'muscle' retraction. Read that part carefully! We also didn't fully understand how to quantify it's force properties given that as it contracts, it gets gemetrically weaker. If we'd had it in the offseason to play with, maybe we would have considered it for the game.

[mageida]

We are actually thinking about this too. But wouldn't it get weaker as it goes because the pressure goes down?

[Al Skierkiewicz]

I was just wondering what part of the robot rules do you think makes these devices legal for the robot?

[sanddrag]

Originally Posted by Al Skierkiewicz

I was just wondering what part of the robot rules do you think makes these devices legal for the robot?

The Pneumatics section? Also, it would seem silly to offer such a device on FIRST Choice if it were not legal. Are we not allowed to use any COTS pneumatics parts so long as they meet the minimum specified ratings in the manual and remain unmodified? I'll admit, I did quickly skim through that section of the manual. Perhaps I shall revisit it.

[spiffyspleen]

By pneumatic muscle I assume people mean using a pneumatic piston to move the joint of an arm up or down. If this is against the rules then I will lose any respect I still have for FIRST.

[Jon Stratis]

spiffyspleen - That's not what they mean. Available from FIRST Choice this year is a "pneumatic muscle" - see page 9 here: http://files.andymark.com/2011FirstChoiceList.pdf

<R66> states:

In addition to the items included in the KOP, pneumatic system items specifically permitted on 2011 FRC ROBOTS include the following items. All included items must be “off the shelf” COTS pneumatic devices rated by their manufacturers for working pressure of at least 125psi and burst pressure of 250psi, and used in their original, unaltered condition (except as required for assembly with other components).
A. Pneumatic pressure vent plug valves functionally equivalent to those provided in the KOP,
B. Solenoid valves with a maximum ⅛” NPT port diameter, and a maximum Cv of 0.32 (if non-KOP valves are used, the team will be required to provide part documentation validating that the valves meet these constraints).
Solenoid valves that are rated for a maximum working pressure that is less than 125psi rating mandated above are permitted, however if employed, an additional pressure relief valve must be added to the low pressure side of the main regulator. The additional relief valve must be set to a lower pressure than the maximum pressure rating for the solenoid valve.
C. Additional 0.160” inside diameter pneumatic tubing functionally equivalent to that provided in the KOP, with the pressure rating clearly factory-printed on the exterior of the tubing,
D. Pressure transducers, pressure gauges, and connecting fittings,
E. Pressure regulators with a maximum bypass pressure of no more than 60psi,
F. For the purposes of the FRC, a device that creates a vacuum is not considered to be a pneumatic device and are not subject to the pneumatic rules (although they must still satisfy all other appropriate rules). These include, but are not limited to, venturi-type vacuum generators and off-the-shelf vacuum devices (as long as they are powered by provided or permitted motors).
G. For the purposes of the FRC, closed-loop COTS pneumatic (gas) shocks are not considered pneumatic devices, and are not subject to the pneumatic rules (although they must still satisfy all other appropriate rules).
H. For the purposes of the FRC, air-filled (pneumatic) wheels are not considered pneumatic devices, and are not subject to the pneumatic rules (although they must still satisfy all other appropriate rules)

As near as I can tell, the pneumatic muscle available from FIRST Choice is not specifically listed here. So, this begs the question... are items from FIRST Choice considered to be part of the KoP, or simply COTS items? I know there's a thread around here somewhere discussing that very question (mostly for the purposes of cost accounting), but can't seem to find it at the moment.

From Bill's Blog, http://frcdirector.blogspot.com/2010...st-choice.html, you would expect FIRST Choice to be considered part of the kit, as he states:

FIRST Choice is an online extension of the traditional KoP where teams can pick and choose the items they would like to add to their kits.

But from the game manual, the kit is defined as:

KIT OF PARTS (KOP) – the collection of items listed in the 2011 Kit of Parts Checklist provided on the FIRST website at http://www.usfirst.org/frc/competitionmanual.

And the parts from FIRST Choice are not listed in the checklist. This likely needs some clarification from the GDC before anyone really knows what to do with those items from FIRST Choice...

[MasonMM]

Originally Posted by Al Skierkiewicz

I was just wondering what part of the robot rules do you think makes these devices legal for the robot?

The pneumatic muscle is offered as a part of FIRST Choice on Andymark. FIRST Choice is an online extension of the Kit of Parts. Items included in the kit of parts are allowed on the robot.

<R66> In addition to the items included in the KOP, pneumatic system items specifically permitted
on 2011 FRC ROBOTS include the following items....

http://www.festo.com/cms/en-us_us/5030.htm

Pneumatic Muscle is a different type of actuator then the standard piston... Its worth looking into as a new option for short distance high force motion.

[Jon Stratis]

MasonMM - make sure you carefully read the definition of the Kit of Parts - it does NOT officially include FIRST Choice. As such, items obtained from FIRST choice must currently be considered standard COTS items, and thus accounted for in both individual rules (like this one) and for purposes of cost accounting. I would hope that will change to better reflect the Bill's Blog post on FIRST Choice, but that's a question for the GDC to answer, not any of us. Until then, we have to go with the letter of the rules as they stand now.

[Bill_B]

That FESTO link leads to an amazing device demonstration they call the air arm.
air arm Someone should contact the company and ask if they would bring this device to St. Louis. They have a lot of other projects listed at the same site. Worth your time to look at their films. Actually any of their projects would go over very well at Championships.

[JohnHorton]

Originally Posted by Bill_B

...
air arm Someone should contact the company and ask if they would bring this device to St. Louis. ...

Seconded. I'll be there this year, and I'd love to see that in action. Maybe we'll see something similar on a bot.