Ways of using compressed air to shoot the ball

[mechanical_robot]

Before I start this is not supposed to be a serious thread more of a fun thread, but hey who know you might be able to implement a air cannon to shoot the ball.


So what are some ways you could get a shooter that uses compressed air to shoot the ball into the goal.
Here is the restrictions

• Cannot damage the ball too badly
• Must be safe for all humans
• Must be safe for the robot shooting the ball
• Must be safe for robots surrounding the robot shooting the ball

Little fun challenge to work out also the shooter would have to fit on the robot itself. and be able to reload. So what are your guys ideas on this?

[dtengineering]

Here's one way... http://www.youtube.com/watch?v=f5jyd7H4JW0

Hopefully Youtube will offer up the related videos... we were inspired in our design by 1726. (Still grateful for that, guys, even six years later.) If not, this thread might have more information http://www.chiefdelphi.com/forums/sh...ht=1726+launch

Okay, I know you mean "use compressed air like a potato gun", but while there are ways to do that, I don't think many of them are FRC legal, and those that are legal might not be particularly practical. But you CAN launch a much larger, heavier ball using compressed air.

Jason

[JamesCH95]

See my team's history section, 2008, for our track ball launcher: http://www.frcteam95.org/wp/history/

A close-up of the two-stage piston launcher:



If memory serves it was capable of launching the track ball 10-12 feet in the air. The trick is using many small pistons (and thus many solenoids) so that air flow into your launching mechanism is legally maximized.

Just cite your source please

[nickcvet89]

You can do similar to what paintball guns do. Most paintball guns either operate on a spool or poppet valve. I posted a link below of an animation of a spool valve. Essentially there is a bolt that is actuated by air. The bolt in a cylinder is similar to a piston but instead the bolt is a hollow tube that has hole through it and a flange at the back to seal the cylinder. At the back of the cylinder is a pin with an oring on it that rides in and out of the hole of the bolt. When compressed air is introduced into the rear, the bolt moves forward til the oring completely exits the bolt, letting air pass through the bolt. The function of this is two fold. The bolt moves forward initially for a short distance to accelerate the ball. This initial acceleration is key because if the ball was to be propelled only by air from the rest, the pressure in the compressed air would have to be incredibly high to propel the ball. Once the initial acceleration is generated, the air accelerates the ball further once the bolt clears the rear oring. Since the initial acceleration is generated by the bolt, very little air is necessary to propel it further. This is why most new paintball guns operated at pressures between 65-120psi depending on how fast you want the ball to travel. An increase in pressure, increases speed and vice versa. This could be theoretically done for a competition like this if FIRST ever allowed to have multiple compressors or a single large capacity compressor, with a large storage tank or multiple small ones to generate enough volume. The pressure restrictions would not have to be changed all that much. Also most paintball guns employ the same solenoids we use to toggle between shooting and reloading.

http://www.zdspb.com/media/tech/anim...p_g4_stock.gif

[JamesCH95]

Originally Posted by nickcvet89

You can do similar to what paintball guns do. Most paintball guns either operate on a spool or poppet valve. I posted a link below of an animation of a spool valve. Essentially there is a bolt that is actuated by air. The bolt in a cylinder is similar to a piston but instead the bolt is a hollow tube that has hole through it and a flange at the back to seal the cylinder. At the back of the cylinder is a pin with an oring on it that rides in and out of the hole of the bolt. When compressed air is introduced into the rear, the bolt moves forward til the oring completely exits the bolt, letting air pass through the bolt. The function of this is two fold. The bolt moves forward initially for a short distance to accelerate the ball. This initial acceleration is key because if the ball was to be propelled only by air from the rest, the pressure in the compressed air would have to be incredibly high to propel the ball. Once the initial acceleration is generated, the air accelerates the ball further once the bolt clears the rear oring. Since the initial acceleration is generated by the bolt, very little air is necessary to propel it further. This is why most new paintball guns operated at pressures between 65-120psi depending on how fast you want the ball to travel. An increase in pressure, increases speed and vice versa. This could be theoretically done for a competition like this if FIRST ever allowed to have multiple compressors or a single large capacity compressor, with a large storage tank or multiple small ones to generate enough volume. The pressure restrictions would not have to be changed all that much. Also most paintball guns employ the same solenoids we use to toggle between shooting and reloading.

http://www.zdspb.com/media/tech/anim...p_g4_stock.gif

Do you think that your suggestion is legal per R77?

[nickcvet89]

Since I don't have the rules handy, probably not, but as I stated the rules would have to be tweaked in order to allow something like this. To generate the amount of volume needed to shoot a ball of this size would be huge. You would have to add a lot of the clippard air tanks to your robot. Additionally, the legal compressor specs for most years, makes multiple shots unrealistic because the spec doesn't allow for very high CFM leading to slow fill times.