Piston throw control [Archive]

Mr. Ivey

10-02-2004, 19:22

I was just wondering if any team had tried to control the amount of throw in a piston, like stoppint it 1/4, 1/2, or 3/4 of the way through it's stroke. I believe it is possible, just like in a hydrolic system on a piece of heavy machinery, but I am having some troubles actually making it happen. If anyone has any ideas I would love to hear them.
Ivey

Rickertsen2

10-02-2004, 19:25

I was just wondering if any team had tried to control the amount of throw in a piston, like stoppint it 1/4, 1/2, or 3/4 of the way through it's stroke. I believe it is possible, just like in a hydrolic system on a piece of heavy machinery, but I am having some troubles actually making it happen. If anyone has any ideas I would love to hear them.
Ivey
This is common in industry, only with a different type of valve. There is a giamongous thread o nthis topic. I'm sure you can find it.

Rob Colatutto

10-02-2004, 19:25

http://www.chiefdelphi.com/forums/showthread.php?t=23934&highlight=pneumatics
This thread has much on the subject and yes it is possible with our parts. 263 has done it on 01 and 03.

ngreen

10-02-2004, 19:48

And 1108 did it in 2003 with our arms. I lay out how to put the system together several times in that thread and there is much discussion on issues involved with it.

Rhs953

10-02-2004, 20:51

Its practically impossible to do. Its either all or nothing.

______________________________
I didn't break it!

ngreen

10-02-2004, 21:08

Its practically impossible to do. Its either all or nothing.

Read posted thread. It is possible. I've done it. It works well.

edit: Sorry, that might be harsh. By routing the exhaust of a double solenoid you can do more things like controlling the throw of the piston. By switching between atmosphere and a stop on a single solenoid you control the piston. I've put diagrams and pictures up in the other thread. Look there for the details.

KenWittlief

10-02-2004, 22:05

Its practically impossible to do. Its either all or nothing.

______________________________
I didn't break it!

the impossible - thats what engineers do every day, turn the impossible into something we end up taking for granted :^)

alexrobotics

13-02-2004, 14:09

Our team is trying to do something similar with an arm and it must be fairly acute b/c we are trying to use the pneumatics to position the multiplier ball.
I have looked through the other thread and I was wondering if anyone has some great up close pictures that make a multi-position arm without a lot of programming.

ngreen

13-02-2004, 14:17

The minimal amount of programming is a on/off switch for the single solenoid and a extended/retracted switch for the double solenoid. You can do this manually for practice. Choose the direction you want extend/retract and then turn on the single to move and turn off to stop where you want. Slow movements down by using the needle valves on the cyclinder and closing them all the way and then slightly opening them.

sirbleedsalot

13-02-2004, 22:39

If you want it to stop in the same place all the time just take a piece of pipe and cut it to the right length and then slide it onto the shaft

Mr. Ivey

17-02-2004, 15:23

Or I could just buy the SMC "off the shelf" three stage solenoid...
ivey

pras870

17-02-2004, 15:53

Actually, if you follow the flow chart, you cannot use any off the shelf solenoids.

Electronics (yes) -> Is the part a motor, solenoid, pump, or other actuator? (yes) -> No, it may not be used.