How to improve power in piston shooter
 

We are currently using our pistons as an extra push for a pass as we are a inbound robot. Our pistons are not strong enough to shoot over the truss and i feel as though it would be a nice improvement to get working. Any help on how to get pistons to shoot higher and farther would be greatly appreciated.:)

Re: How to improve power in piston shooter
 

It would help if you would give specs on what you are currently using to launch the ball.:) :)

Re: How to improve power in piston shooter
 

1. Get the highest Cv flow valves you can get. KOP ones are about .25Cv, you can find others that are higher, we found some that were .8Cv, makes a big difference.
2. Mount solenoid valves with a double male nipple directly to the piston if you have the room. No using tubing is huge as well between solenoid and piston.
3. Next create a low pressure (60) reservior (tank) right before the solenoid with no elbow fittings and use the shortest length of tubing as possible. Length is bad, avoid length.

That should help:)

remember the solenoid (valve) openings must be 1/8" as per rules and must be able to operate at 120psi, Cv can be high as you can get....

Re: How to improve power in piston shooter
 

Make sure your operating pressure is set to 60 PSI. If you are only pushing one direction, try removing the fitting from the return end of the cylinder. That might let the air leave that section faster, potentially giving you a more powerful shot, provided the cylinder will gravity return to its original position.

Re: How to improve power in piston shooter
 

As stated, it would really depend on your current setup, but my team also went through trying to increase range w/ pneumatic and these the fixes that helped us:

1. Higher air-flow solenoids.
2. If you are using some sort of level arm, extend the arm.
3. Leaving the return side of the pistons open to vent to the air, and have the pistons return some other way (ex: surgical tubing, vacuum, ect.).
4. We had a separate air tank for each piston on our shooter, thus adding more air volume on the 60 psi side.
5. If possible, mount solenoids directly to each piston

Here are some ideas that either didn't help us or didn't apply in our situation, but may benefit you:

1. Adding more pistons.
2. Increasing piston bore.
3. Assisting the pistons (ex: surgical tubing, spring, ect)

Hope this helps,
-Nick

Re: How to improve power in piston shooter
 

Not quite right.

Per R77-D, if the solenoid valves are rated for less than 125 psi, an additional pressure relief valve must be added to the low pressure side of your system, and set to a pressure lower than the rating of the valve.

The interesting part of this is actually setting the valve. When we cranked up our low pressure side to 100 psi (the max of the regulator, but below the rating of our solenoids), we discovered a couple of marginal fittings.

-Karlis

Re: How to improve power in piston shooter
 

Increasing the diameter of your cylinders will most likely REDUCE the "power" of your shot, because it will slow the full activation of the cylinder (bigger cylinder - more to fill). If you need a certain amount of surface area to generate enough lift, then the fastest way to activate that would be increasing the number of cylinders - each with their own solenoid - and DECREASING the size of each cylinder, so they each fill quickly.

We used three .75" diameter by 12 stroke cylinders. The solenoids we are using are from McMaster Carr, and have about three times the flow rate as the standard KOP solenoids. Our shot can cross the truss and reach the human player from the center of the white line.

Two more things...(1) if you are using the cylinders in a direct pushing action, like us - we found that it was essential to have the ball resting on the plungers of the cylinders before the shot rather than have a space between the ends of the cylinders and the ball. Apparently the impact with the ball disrupted the action enough to dissipate some of the power transfer...so "push" don't "punch". and (2) don't try to fix multiple cylinder rods together into one plunger...it is nearly impossible to gang them together without introducing some friction on at least one of the rods, thus reducing power. We made a loose gathering gasket out of bicycle tube to keep the ends of the three cylinders together.

Re: How to improve power in piston shooter
 

As, if not more important than pneumatic design, is the kinematics. As much as possible, you what the line of action of the cylinder should be perpendicular to the axis of rotation.

Re: How to improve power in piston shooter
 

Not necessarily. The dynamics of these shooters is extremely complicated; quite a few designs rely on starting at a significant mechanical disadvantage to work properly.

Re: How to improve power in piston shooter
 

Doesn't change the importance of the kinematics, which is probably what I should said. Even so, the more efficient the kinematics, the less air you have to use to get energy into the ball.

Re: How to improve power in piston shooter
 

Depending on your setup, a potentially easy improvement is to add gas springs alongside the pneumatic cylinders to assist them on the way up.
I'm surprised that I haven't seen this done yet given how much it could add.
All of the force that the cylinder is using to launch is also being used to retract (not as strong on retract, but still packs a punch). Rather than having all of that go to waste, you can use it to store up energy in a gas spring. Something like these:
http://www.mcmaster.com/#gas-springs/=rc2sdb

You may also need to employ some of the tricks people have mentioned already about increasing the flow rate of your cylinder - otherwise the spring may just be slowed right down resulting in more than enough power, but not enough speed.


Best of luck!

Re: How to improve power in piston shooter
 

Nearly every pneumatic launcher I have seen doesn't plumb the retraction of the cylinder at all. Most of them rely on gravity for return. This allows the cylinders to fire much faster as they don't have to exhaust through tubing or a solenoid.

Re: How to improve power in piston shooter
 

here is the link http://www.princessauto.com/pal/en/P...nder/8188211.p to the specs on our pneumatic cylinder

Re: How to improve power in piston shooter
 

I think he wanted to see the whole launcher setup, not just the specs on the cylinder.

Do yo have a few pictures of your robot that would show us how it works?

Re: How to improve power in piston shooter
 

Thank you for the information do you have any recommendations of where we can get some?

Re: How to improve power in piston shooter
 

McMaster Carr item 6124K511 is a great one:
http://www.mcmaster.com/#catalog/120/1007/=rc4031

Re: How to improve power in piston shooter
 

This one has a CV of 1.0 with a 1/8 npt port, Which is 3 or 4 times larger than the SMC / Festo valves you can get from AndyMark or Vex. We haven't used them though, so don't consider this an endorsement:

http://www.mcmaster.com/#6425k11/=rc3uws

Re: How to improve power in piston shooter
 

FRC558 will endorse them, they are currently running well on our machine.

Re: How to improve power in piston shooter
 

Cool. Do you have the actual manufacturer and model number then? It would be nice to look up the original spec sheet.

Re: How to improve power in piston shooter
 

The brand is Norgren and they can be found on McMaster Carr

Re: How to improve power in piston shooter
 

Sure, they are made by Numatics Inc.The link should take you right to the product page.

Re: How to improve power in piston shooter
 

We use the Nitra AVS 3211-24d solenoids from Automation Direct.
http://www.automationdirect.com/adc/...)/AVS-3211-24D
These are 24v with a Cv of .78. We use these on 10" Bimba 1.5" bore cylinders and have been really happy with them.
Plus we used the product voucher from FIRST... Even if you do not use the voucher they are about 21.00 each.

Good luck

Aloha