Is it possible to shoot the ball with pneumatics?
 

My team has done some prototyping with some pneumatics to shoot the ball. We used a lever arm but it seem to never get as high as we would like so we have been trying to play with one v. two cylinders. Then I came up with the best way to wire the pneumatics to get the best performance. I haven't yet tested it out but I need help to see if it is even possible. I have attached a diagram for the system. One is the diagram for how its set up and the other is for the shooter. The red is the cylinders. Thanks!

Re: Is it possible to shoot the ball with pneumatics?
 

It appears to be possible.

http://www.youtube.com/watch?v=QRmHqCGYnwI

Re: Is it possible to shoot the ball with pneumatics?
 

Or this:

http://www.youtube.com/watch?v=YDuA0...ature=youtu.be

Re: Is it possible to shoot the ball with pneumatics?
 

That's a pretty impressive one. I wonder how they managed to get that much oomph out of a single cylinder (which looks like a rather small one, at that).

449 got our first-iteration prototype pneumatic shooter working (i.e. shooting through the goal from the ground) today, three days after deciding to try one. Not quite that slick, but very functional. It's not all that difficult; the geometry of the piston mount is the trick, look closely at some of the catapult designs teams have posted to get an idea of how to set one up.

You don't need any tricks with multiple solenoids or whatever to maximize airflow, by the way - we were getting the ball to the required height with a single solenoid feeding three cylinders.

Re: Is it possible to shoot the ball with pneumatics?
 

Yes, it's possible. Our prototype did it today and scored the high goal. It's lousy but would only need to be about twice as good for the actual competition.

We used a pretty big cylinder operating on a lever arm. This principal worked for us ok also in 2008.

Re: Is it possible to shoot the ball with pneumatics?
 

What kind of distance are you getting on the shots? Right under the goal, or full court truss pass?

Re: Is it possible to shoot the ball with pneumatics?
 

Not full-court truss pass, but we can score from a solid 5-10 feet away if we put it on the right trajectory. Our strategy doesn't involve a super-powered shooter, though.

Re: Is it possible to shoot the ball with pneumatics?
 

It is very possible! Makes for some great footage too.

842, 1212, and possibly 2403? I predict lots of pneumatic catapults at AZ this year.

Re: Is it possible to shoot the ball with pneumatics?
 

We're prototyping one too. We're hoping to get it running tomorrow.

Re: Is it possible to shoot the ball with pneumatics?
 

:yikes: :yikes: :yikes:

We've come up with a 3-stage piston assembly. It has the power to reach the high goal but questions have arisen about how to seat the ball for a optimal shot. This could answer both this and how to mount the mechanism. Thanks for the links

Re: Is it possible to shoot the ball with pneumatics?
 

Just be careful to comply with R89 A

Your pressure vent plug MUST be able to vent ALL stored air pressure. If the solenoid valve is closed and the vent plug is open, the pressure is not released. This will fail inspection.

Re: Is it possible to shoot the ball with pneumatics?
 

Go Pneumatic Catapults! Its working great for us!

Re: Is it possible to shoot the ball with pneumatics?
 

Prepressurize the piston, but have the stroke locked by a latch. That way, there will be a ton of energy built up, capable of extending the piston in very little time. We, team 1165, have also prototyped a pneumatic shooter, that basically catapults or flings the ball effectively.

When designing this system, make sure your latch is very well-made because there will be a ton of pressure in it, especially at 60PSI working pressure!

Also, beware of hands because this suddenly flings with a ton of force, which has the capability to de-hand you (if that is a word).

I'll try to inquire and post a video of this shooter as soon as we finish the changes to it!

Re: Is it possible to shoot the ball with pneumatics?
 

will this release all the air in the system? http://www.chiefdelphi.com/forums/at...0&d=1389572570

I think it does, I will double check in the morning.....

Re: Is it possible to shoot the ball with pneumatics?
 

You may not want to go with a locking system, see Don Rotollo's post...
There is another way, you do not need to use locking method, see diagram on the first post on this at top of page

Re: Is it possible to shoot the ball with pneumatics?
 

You don't have to. I'm just saying that that's what we did, it works, and is another possibility.

Oh yeah, the shooter has a decent footprint too!

Re: Is it possible to shoot the ball with pneumatics?
 

yup, you are right about that!

Re: Is it possible to shoot the ball with pneumatics?
 

I'm not seeing a valve to depressurize the system in that diagram.

However if you put the drain valve anywhere between the compressor and the solenoids it will drain the entire system as long as you don't add a check valve in there somewhere.

Re: Is it possible to shoot the ball with pneumatics?
 

Is it possible? Yes. A number of teams did this in 2008. I distinctly recall Blue Cheese, with their robot Blue Cheddar, at VCU:

http://www.youtube.com/watch?v=c1LK0JnMPFI
http://www.youtube.com/watch?v=KMZaZiNkDFI

There are probably other videos with better launch characteristics out there. Quite impressive. And that ball was 41" diameter, and 7 pounds. A real crowd pleaser!

As I recall, they did not latch the launcher. They did it all with improving the speed of the air flow into the pistons by reducing air drag. That, and they had four parallel pistons, about 1" diameter, maybe 8" long, pushing their shooter/sling. (I can't remember the precise dimensions for sure, but I did talk to them a bit during Saturday morning at VCU, observing and admiring their system.)

Ways to improve air speed into the pistons:

1) Having air reservoirs/tanks on the low side. A main source of air flow drag in pneumatics is the regulator. If the air is in working (low pressure) side tanks, that is no longer a source of drag for the air flow into the piston. Keep in mind that means that those tanks are only at 60 psi, so they don't store as much energy. You'll still need high side tanks.

2) Have a dedicated supply line for each piston. Tank to solenoid to piston intake.

3) Piston exhaust is open, with even the brass fitting removed. Be sure to use double acting pistons: single acting pistons have springs which will reduce your power/speed. With this setup, you'll have to have an alternative way to retract the shooter. Gravity may be sufficient. Pushing the ball onto the shooter may be sufficient to retract the shooter.

Latches are necessarily complicated mechanisms. More complexity means more potential failure points. If you don't need a latch, avoid using it.

Re: Is it possible to shoot the ball with pneumatics?
 

We got the ball to fly. Finally.

http://www.youtube.com/watch?v=akZQIIDi12I

and it does discharge all the air from the system when we open the release valve, as usual.

Re: Is it possible to shoot the ball with pneumatics?
 

I'd like to thank you for sharing your 2008 catapult geometry in an earlier thread - it's been very helpful in developing our prototype at 449. We're currently running ours off of just one solenoid, currently, and it's working reasonably well for close shots:



That was with two 1.125''-bore, 8''-stroke cylinders, for reference; it shoots a bit further when we hook up a third one. We're going to experiment with different/better pneumatic setups and different cylinders in the coming week, as well as different arm geometries.

Re: Is it possible to shoot the ball with pneumatics?
 

You're welcome!

After talking with a mentor on team 842, we are going to play with different solenoid valves, and pneumatic plumbing.

One thing we've learned over the years, you want it to shoot significantly farther than "just enough".