Pneumatic Restrictions & Improvments

[lynca]

In 2014 we saw a large upswing of people using pneumatic for their launching mechanism. This created quite a discussion on rules and legal restrictions for pneumatics.

If you are the GDC , How would you improve the pneumatics rules next year ?

For example.

Why are we limiting CV , tubing and port size ? (CD thread )

Why do we limit low-pressure to 60 psi compared to 70 or 80 psi ?

Are there any devices that could improve the pneumatic experience for most teams ?

[magnets]

Originally Posted by lynca

In 2014 we saw a large upswing of people using pneumatic for their launching mechanism. This created quite a discussion on rules and legal restrictions for pneumatics.

If you are the GDC , How would you improve the pneumatics rules next year ?

For example.

Why are we limiting CV , tubing and port size ? (CD thread )

Why do we limit low-pressure to 60 psi compared to 70 or 80 psi ?

Are there any devices that could improve the pneumatic experience for most teams ?

First of all, pneumatics restrictions were lessened by a lot this year. The CV of the valve restriction was removed.

The reason the GDC limits CV is for safety. If we had unlimited CV, and someone were to put their head against a medium to large size pneumatic cylinder, and it is accidentally actuated, the person would die.

[sanddrag]

Quick exhaust valves. PLEASE

[headlight]

Originally Posted by sanddrag

Quick exhaust valves. PLEASE

Quick exhaust valves can be approximated by using a 2 port solenoid valve at the cylinder and controlling it through software to provide an additional dump path. It would be way easier if we could just use quick exhaust fittings.

I would like to be able to use mufflers. Please. It is a small purely aesthetic change but high flow vent caps on the solenoid manifolds ensure that nothing gets inside. And a high flow muffler on the manual pressure release vent plug just helps keep sound down and makes sure there isn't a blast of air blowing stuff around whenever you dump pressure.

If would be nice if the pneumatic rules were just slightly more clarified and consistent. Things like ball valves, can they be used or not? or can they only be used as the main pressure dump?

There is also an entire world of pneumatic logic that hasn't been particularly capitalized on.

[nuclearnerd]

Originally Posted by sanddrag

Quick exhaust valves. PLEASE

Seconded.

Look, I get that there need to be restrictions on the pneumatic power available, but think about it this way: When the game requires your robot to through 4lb balls 10 feet in the air, you're going to need a certain amount of power. That power can be either delivered through a sketchy assembly of springs and a latch mechanism that was likely never meant to work under load
*or*
it can be delivered with commercial-off-the-shelf tubes, valves and cylinders that are engineered for the application, can be reliably assembled without machining resources, and have published specifications to govern their use.

Honestly, pneumatics are the safest way to deploy a given amount of power IMHO.

[Oblarg]

Originally Posted by nuclearnerd

Seconded.

Look, I get that there need to be restrictions on the pneumatic power available, but think about it this way: When the game requires your robot to through 4lb balls 10 feet in the air, you're going to need a certain amount of power. That power can be either delivered through a sketchy assembly of springs and a latch mechanism that was likely never meant to work under load
*or*
it can be delivered with commercial-off-the-shelf tubes, valves and cylinders that are engineered for the application, can be reliably assembled without machining resources, and have published specifications to govern their use.

Honestly, pneumatics are the safest way to deploy a given amount of power IMHO.

It's worth noting that allowing quick exhaust valves doesn't really increase the amount of available power, since it's legal to simply leave one of the orifices on a two-stroke cylinder open to the atmosphere. I imagine the motivation for not allowing them is something else (thought I have no idea what that may be).

[AdamHeard]

Originally Posted by Oblarg

It's worth noting that allowing quick exhaust valves doesn't really increase the amount of available power, since it's legal to simply leave one of the orifices on a two-stroke cylinder open to the atmosphere. I imagine the motivation for not allowing them is something else (thought I have no idea what that may be).

Was this unique to this year?

A 2011 Einstein team ran quick exhaust valves (968).

[Mk.32]

Originally Posted by AdamHeard

Was this unique to this year?

A 2011 Einstein team ran quick exhaust valves (968).

I believe it was a Q/A:

https://frc-qa.usfirst.org/Question/...-per-rule-77-f

And the tread this year concerning it: http://www.chiefdelphi.com/forums/sh...d.php?t=124806

[sanddrag]

Originally Posted by Oblarg

It's worth noting that allowing quick exhaust valves doesn't really increase the amount of available power, since it's legal to simply leave one of the orifices on a two-stroke cylinder open to the atmosphere.

And this is why they should be legal. The only conceivable safety concern I can come up with relating to their use is you can move fast in two directions instead of just one with an open port Anyhow, to the OP, great thread.

[nuclearnerd]

Originally Posted by sanddrag

And this is why they should be legal. The only conceivable safety concern I can come up with relating to their use is you can move fast in two directions instead of just one with an open port Anyhow, to the OP, great thread.

Agreed. Without quick exhaust valves, you're forced to either halve the flowrate by running exhaust air back to the valve, or introduce some other mechanism to retract the cylinder - a complicated waste of weight.

I maintain that rules that discourage the use of pneumatics actually reduce safety. I would trust a factory-tested solenoid valve over a gerry-rigged latch holding back hundreds of pounds of spring force.

[Mk.32]

Originally Posted by magnets

First of all, pneumatics restrictions were lessened by a lot this year. The CV of the valve restriction was removed.

The reason the GDC limits CV is for safety. If we had unlimited CV, and someone were to put their head against a medium to large size pneumatic cylinder, and it is accidentally actuated, the person would die.

Even with our current systems that could happen, 2in bore cylinder with 60PSI behind it is a lot of force. Also some spring punchers were just insane in amount of stored energy.

Basically the hose (1/4) and the 1/8 NPT rule limits the "power available".

Personally I want to be able to use a 3000PSI CF paintball tank/regulator so I never have to charge air at a competition but I don't think that's happening anytime soon.

[chrisfl]

We had a pneumatic catapult. I found a way to actuate a 2in bore, 10in stroke at the speed of a 3/4 in bore, 4in stroke. So, staying within the regulations, we had the strength of a 2in bore with the speed of a small, 3/4in bore.

[apples000]

Originally Posted by magnets

First of all, pneumatics restrictions were lessened by a lot this year. The CV of the valve restriction was removed.

The reason the GDC limits CV is for safety. If we had unlimited CV, and someone were to put their head against a medium to large size pneumatic cylinder, and it is accidentally actuated, the person would die.

Very true.

This year, we were playing around with a pneumatic launcher, and we wanted to try it with shop air. Strangely, no air was coming from the valve, and after closing all the other valves in the room (it shuts off the compressor if it detects a leak) so I went to go to the maintenance room to check on the big compressor. It turns out the room's dump valve had a faulty contact, and when I opened up the electrical panel, the valve opened, pressurizing the cylinder very, very quickly. The cylinder and its bracket went flying across the table, both fittings were torn/snapped off. It left a sizeable dent in the sheet steel counter, and chipped off part of our CNC's safety shield!

[DampRobot]

Let us charge with offboard air compressors, even if we have one onboard.

If it's made legal for everyone, it's no longer a competitive advantage, and there are ways to let it happen safely. I'd argue it's much safer to go into the match with a cool compressor than a hot one which can melt tubing or drag on battery voltage.

[Mk.32]

Originally Posted by DampRobot

Let us charge with offboard air compressors, even if we have one onboard.

If it's made legal for everyone, it's no longer a competitive advantage, and there are ways to let it happen safely. I'd argue it's much safer to go into the match with a cool compressor than a hot one which can melt tubing or drag on battery voltage.

As a robot 2014 inspector, this can be legal. You just have to power it from the robot. With either an 2nd spike or just unplugging the off board temporary. I know 987 actually had two off board compressors they switch between to make sure they never over heated.

Now I understand you probably mean just plugged in a off board into a battery, or using a shop air compressor. But safety concerns I would guess, have first to ban them and we have no power over that. Again rules many change in 2015, but doubt they would change this one.