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David55
03-20-2006, 05:23 PM
Just wondering if anyone has tried out the vex pneumatic kits and what they think about it...

I know it is very very expensive but it just looks too cool!

David


http://www.vexlabs.com/vex-robotics-pneumatic-parts.shtml

artdutra04
03-20-2006, 06:01 PM
Just wondering if anyone has tried out the vex pneumatic kits and what they think about it...

I know it is very very expensive but it just looks too cool!

DavidI've used the Vex pneumatics before, and I love them! :p Here is the robot that our group used them on:

http://www.chiefdelphi.com/media/photos/21991

And here is a better photo of the double-acting cylinder that we used:

http://www.team228.org/images/VEX/wpi-frontiers-vex-pneumatics.jpg

The pneumatics work really well for any sort of linear motion devices that have two positions only. Pneumatics are different from hydraulics; with pneumatics you cannot get intermediate positions with the pneumatics (you only get fully retracted/extended), while hydraulics can be stopped mid-stroke and hold their position. This is because the air is compressible while a liquid (as in the hydraulics fluid) is not.

As for some ideas that can use pneumatics - the sky is the limit. Arms, grabbers, claws, shifting transmissions, etc. and much more can all be used with the pneumatics. ;)

David55
03-21-2006, 02:49 AM
It seems that they are very good and can add a lot of complex features to your robot. But are they really worth the price? (230$ for two double acting cylinders)
Is there any simple and effective way of transferring a servo to linear motion?

artdutra04
03-21-2006, 07:55 AM
It seems that they are very good and can add a lot of complex features to your robot. But are they really worth the price? (230$ for two double acting cylinders)
Is there any simple and effective way of transferring a servo to linear motion?It all depends on what you want to accomplish with them. In many applications, it is possible for the rotational motion of a servo to be turned into linear motion. A prime example of this would be the pistons on a steam locomotive (http://www.burningwell.org/gallery2/main.php?g2_view=core.DownloadItem&g2_itemId=2857) or an internal combustion (http://www.siu.edu/~autoclub/images/engine1.jpg) engine. Ideas like this may work in some situations, but not in others. As with most things in life, there is no golden answer to which is better. Everything depends on what you want to accomplish how you design / build it. $230 may seem like a lot of money initially, but if you plan on using the pneumatics kit a lot, then it's a really good deal.

gabrielse
03-23-2006, 05:31 PM
I've used the Vex pneumatics before, and I love them! :p Here is the robot that our group used them on:

http://www.chiefdelphi.com/media/photos/21991

And here is a better photo of the double-acting cylinder that we used:

http://www.team228.org/images/VEX/wpi-frontiers-vex-pneumatics.jpg

The pneumatics work really well for any sort of linear motion devices that have two positions only. Pneumatics are different from hydraulics; with pneumatics you cannot get intermediate positions with the pneumatics (you only get fully retracted/extended), while hydraulics can be stopped mid-stroke and hold their position. This is because the air is compressible while a liquid (as in the hydraulics fluid) is not.

As for some ideas that can use pneumatics - the sky is the limit. Arms, grabbers, claws, shifting transmissions, etc. and much more can all be used with the pneumatics. ;)

We just bought the double action cylinder kit from Vex Labs. We want to program them in EasyC but we can't find any documentation. Please help.

artdutra04
03-23-2006, 11:56 PM
We just bought the double action cylinder kit from Vex Labs. We want to program them in EasyC but we can't find any documentation. Please help.Since the Vex Pneumatics are beta parts from VexLabs, there is no documentation included with EasyC on how to program the pneumtics. However, fear not - the pneumatics are easy to program. All you need to do is plug the solinoids into the Digital Output ports. (Not the motor ports!) In EasyC, use the SetDigitalOutput() block and to change the state of that digital output port. In the following code snippet from EasyC, the SetDigitalOutput will toggle the solinoid state to 0 and then 1 and then back to 0 every second. Whenever the solinoid changes state, the pneumatic cylinder will move to the other limit of its travel.
while ( 1 )
{
SetDigitalOutput ( 16 , 1 ) ;
Wait ( 1000 ) ;
SetDigitalOutput ( 16 , 0 ) ;
Wait ( 1000 ) ;
}

SamC
03-31-2006, 08:40 PM
couldn't you use the Pneumatics in the kit of parts from the FRC tourniment and before each use pump the cylenders with the compressor?

Donut
03-31-2006, 09:56 PM
couldn't you use the Pneumatics in the kit of parts from the FRC tourniment and before each use pump the cylenders with the compressor?

That depends, what power do those solenoids need? Most of those pneumatics are probably too big also.