Flow control?

[Bruceb]

that much I understood. What I dont understand is
#4 Use low side storage tanks as close to the solenoid as possible.

Can you explain that?

[Mr V]

Originally Posted by Bruceb

that much I understood. What I dont understand is
#4 Use low side storage tanks as close to the solenoid as possible.

Can you explain that?

The regulator and hose in proportion to its length create restrictions. So if you've got a low pressure storage tank then you eliminate the regulator's restrictions and if you place it close to the valve as possible and the valve as close as possible to the cylinder you minimize the restriction caused by the hose.

[cmrnpizzo14]

One thing that you can do to help the extension speed of the piston is have 2 cylinders and some form of latch. The large cylinder you will punch the ball with is set up so that the latch will prevent it from extending until the smaller cylinder releases the latch. This way you can run air through the solenoid into the large cylinder to "pre-pressurize" it then release the latch. With the air already in the cylinder and not having to flow through the solenoid it should extend faster because it is not limited by the flow through the solenoid.

[hrench]

In 2008 team 1108 used large pneumatic cylinders to catapult the ball by holding the catapult frame down with hard-drive (neodyniem) magnets. The pressure built in the cylinders to about 50 psi before the magnets were overcome, then the whole thing gives at once.

you could also do this by 'vacuuming' the ball down as a latch or even put a car-door-type latch on the catapult. When the cylinders are pressurized you open it.

But I think the magnet thing is easiest.

[JamesCH95]

In addition to the many other good suggestions in this thread: use as many cylinders as you reasonably can. Many small cylinders can be driven by many solenoid valves, increasing flow.

For random mechanism A you could use a single 1.5in cylinder or four 0.75in cylinders, both generate the same total force. Assuming all else is equal (i.e. factors IndySam brought up) the 0.75in cylinders will actuate about 4x faster because they will flow through 4 valves instead of just 1 on the 1.5in cylinder.

If using multiple cylinders it would be optimal to have numerous connections to your storage tanks, multiple norgren regulators, and the shortest possible tubing lengths. However, this might not be necessary.

In 2008 my team shot the 40in exercise ball with a two-stage direct-acting pneumatic launcher. Each stage had four 10-12in stroke 3/4 bore air cylinders. Each cylinder had its own solenoid valve.

[MartyG33]

What types of tubing can we use? Can we use copper piping for our entire system if we want?

Also how do I post a new thread?

[Racer26]

There is a rule that dictates what tubing we can use. You should look it up.

[MartyG33]

Originally Posted by Racer26

There is a rule that dictates what tubing we can use. You should look it up.

The rule says functionally the same with the inside diameter set. But does that include copper? It is functionally the same, but it does not act the same.

[EricH]

Originally Posted by MartyG33

The rule says functionally the same with the inside diameter set. But does that include copper? It is functionally the same, but it does not act the same.

The way to read the FRC rules is as follows:

If it is not specifically banned or otherwise disallowed, it is permitted.

Now, the pneumatics rules specifically state that anything that is not specifically permitted is prohibited. Copper tubing, however, would probably fall under the pneumatic tubing (though note: it should be sold as pneumatic tubing if you want to make life a little easier at inspection).


That said, CD is not the Q&A. I suggest asking the Q&A.

[MartyG33]

Originally Posted by EricH

The way to read the FRC rules is as follows:

If it is not specifically banned or otherwise disallowed, it is permitted.

Now, the pneumatics rules specifically state that anything that is not specifically permitted is prohibited. Copper tubing, however, would probably fall under the pneumatic tubing (though note: it should be sold as pneumatic tubing if you want to make life a little easier at inspection).


That said, CD is not the Q&A. I suggest asking the Q&A.

I am brand new to this Chief Delphi stuff. How do I ask the Q&A? (this is our team's second year and I am the new rule master)

[EricH]

Originally Posted by MartyG33

I am brand new to this Chief Delphi stuff. How do I ask the Q&A? (this is our team's second year and I am the new rule master)

http://www.usfirst.org/sites/default...m_User_Q-A.pdf (Linked from http://www.usfirst.org/roboticsprogr...c/game-q-and-a )

Q&A is located at https://frc-qa.usfirst.org/Questions.php.

Short version: Whoever has the TIMS access has the password to the account.

[cgmv123]

Originally Posted by MartyG33

I am brand new to this Chief Delphi stuff. How do I ask the Q&A? (this is our team's second year and I am the new rule master)

Your Main or Alternate Contact has the User ID and password to login to frc-qa.usfirst.org in TIMS.

Don't post questions on multiple threads, it can be confusing.