Pneumatics off board recharge packs
 

We are looking to create an off robot pneumatics recharge pack for this season and have had a hard time finding some good examples to start with. Could CD folks post a few pics of pneumatics off robot recharge packs that they liked. Thanks!

Re: Pneumatics off board recharge packs
 

I think because most of us thought strapping a compressor and an air tank on the back of a human was a bad idea. That slight possibility of a 100PSI rupture causing injury was a primary factor.

You should be able to find that discussion.

Re: Pneumatics off board recharge packs
 

Before we go down this rabbit hole,

JJ, What exactly are you trying to accomplish with the project? When would this be used?

Re: Pneumatics off board recharge packs
 

Also, bear in mind that if you are using this pack--in whatever form--to charge your tanks before matches, the way the rules were for 2015, you won't be able to have an onboard compressor. I want to say someone even Q&A'd it.



(For practice is another story--but then you just have to consider safety and getting the air to the robot.)

Re: Pneumatics off board recharge packs
 

R68

Re: Pneumatics off board recharge packs
 

I'd also like to point out the 2015 R70:
Emphasis mine. While you could have a "pack" (read: self contained module) with the compressor, gauges, hoses and such that comprises a legal, off-robot compressor system, you may NOT have any air storage on that off-robot system.

Re: Pneumatics off board recharge packs
 

Over the weekend we saw FRC 346 had a great air recharge pack. It had all of the things it legally needed and was in a great configuration. Let's say is was 12"x8"x10" I did not take a photo and I should have. So I am looking for some more examples to show my kids so they can make one.

I have no idea if we are going to use it this season, but it looks like a great project for a few kids to take on.

Re: Pneumatics off board recharge packs
 

R74 and R75 of the 2015 rules have simple diagrams showing what should be in the off-board compressor unit. There aren't really enough components to need very much creativity to build it elegantly; just make sure that you can carry it without touching the (hot!) compressor. Some quick-disconnects for the wires (e.g. Andersons) are also in order.

Re: Pneumatics off board recharge packs
 

Not particularly FRC legal, but if you wanted a recharge pack. Probably need to add a regulator. Are if you want to barbecue...

Re: Pneumatics off board recharge packs
 

Will add some pics and spec's when I get to the shop, stay tuned.

Re: Pneumatics hand
 

We are looking to create an grabber pneumatics (hand for this season to school kids at near area to give them chance to play with it,.
any some good examples to start with. Thanks!

Re: Pneumatics off board recharge packs
 

OK a few photo's as you mentioned missing the opportunity to take some.
Attachment 19432

Attachment 19433 We can run off a spare battery, but during competition we are able to power off the robot battery.


Attachment 19434 Gives an appreciation for size.

In a re design we may add slots to the wood frame on the compressor side for improved cooling. Not that we've had an issue, more of a can't hurt improvement.

Re: Pneumatics off board recharge packs
 

You would not be able to use the pack pictured above for competition under either of these 2015 rules - no battery, no switch, and no air tanks can be off board. There may be some other nitnoids, but I stopped looking after these obvious ones.

Re: Pneumatics off board recharge packs
 

I am also very confused by the pictured recharge pack. Not only is it not legal (must be controlled and powered by robot), but having tanks onboard the pack makes no sense to me. I am going to assume that your goal is to fill the tanks on the robot and that you started with the tanks on the pack full before connecting it to the robot. The air stored on board the pack will spread equally through out the system and drop in overall pressure. Then you would have to leave it connected with the compressor running until not only the robot was full, but also the onboard tanks. I believe that it would take an equal amount of time as without tanks to fill the robot, therefore it is unnecessary to have the tanks.

Re: Pneumatics off board recharge packs
 

My guess would be, since it's not controlled by the robot (once again, <R69>), and thus not limited by the pressure switch, they fill those tanks beyond 120psi. They probably use that final pressure regulator to ensure a 120psi fill into their on-board storage.

Re: Pneumatics off board recharge packs
 

It looks like they could turn a valve and disconnect the tanks after the pressure has been equalized. We used a similar setup controlled by the robot in 2014.

Re: Pneumatics off board recharge packs
 

Having the tanks on the recharge pack makes it against r70 as pointed out in post 8. Hope that wasn't used during the season at a competition.

In the past, even when it wasn't against the rules we got a hassle for offboard storage. And having a valve to seperate the tanks from the system wasn't enough, trust wasn't very strong that day...

Re: Pneumatics off board recharge packs
 

If it's not going to be used for competition, why not just get an A/C compressor that will charge much faster? Here is a 150 psi 6 gallon A/C compressor for under $130, much less than the components used for the the module shown. As I figure it, 6 gal of 150 psi air expands to about 7-1/4 gal of 120 psi air, so you can charge five quarts of on-board tank (that's eight of the largest plastic tanks currently on the AndyMark site) to 120 psi from a full charge of the on-board tank, no more electricity needed.

Addendum: After working with the air cannon for several years, I've come to realize that an FRC battery is a very inefficient way of getting compressed air (especially in terms of time, but also of electricity). Unless you have rules that specify that the air must come from a compressor powered by the robot's battery, there are several much better ways! On top of that, the regulator to get from 120 psi to 60 psi is inherently no more than 50% efficient when the tanks are full. Pneumatics are an elegant solution when you want to project a defined force, so I would be willing to put up with inefficiencies. Other than that, I'd try to find a way to use a motor more directly.

Re: Pneumatics off board recharge packs
 

Pictures were asked for and provided.

If you can build a better mousetrap, do so.

All the "concern" is appreciated.

Re: Pneumatics off board recharge packs
 

True, but it is not illegal to use in your shop for refilling a robot during practice.

Re: Pneumatics off board recharge packs
 

Not illegal, but silly. An AC compressor makes much more sense.

Re: Pneumatics off board recharge packs
 

Unless of course you may want to go back to using the compressor on board a robot at some time. This unit is very portable, and with a simple modification, competition legal.

Re: Pneumatics off board recharge packs
 

What modification would that be? Almost all of this device would have to be redesigned to be competition legal (under 2015 rules). You'd have to both remove the air storage and change the electrical system to interface with the robot. At that point, you're basically starting over.

Re: Pneumatics off board recharge packs
 

Thanks for posting.

All, thanks for all of the comments. This was a way more useful question then we realized.

Re: Pneumatics off board recharge packs
 

I will just leave this here.

Re: Pneumatics off board recharge packs
 

Guys,
The dominant 2015 rule here is...
R69 The compressor (permitted per R68) may be located off-board, however the compressor must still be controlled and powered by the ROBOT.
The compressor may be mounted on the ROBOT, or it may be left off the ROBOT and used to pre-charge compressed air in storage tanks on the ROBOT. The intent of this rule is to permit teams to take advantage of the weight savings associated with keeping the compressor off-board. However, using the compressor off-board of the ROBOT does NOT permit non-compliance with any other applicable rules.

In the past the interpretation has changed from year to year. It has been sometimes allowed to have the pressure switch and regulator off board provided the stored air on the robot is at the 60 psi pressure. Any other parts of the pneumatic system must be on the robot and controlled by the robot. This includes the battery and storage tanks. While the team above may use this arrangement (see photos) for demos and post season events, it is likely to be ruled illegal at an FRC event. Sorry.