Chief Delphi - How do we launch this thing? 2014

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- - How do we launch this thing? 2014 (http://www.chiefdelphi.com/forums/showthread.php?t=124040)

Re: How do we launch this thing? 2014

Jim has posted some really good suggestions here... this is, largely, a solved problem. Many teams found a way to launch balls in 2008 that were similar to these ones, but larger and heavier.

Dig back in the forums and videos and team websites if you weren't around FRC in '08.

And watch the BuildBlitz and Robot In Three Days (and a snowstorm) for ideas.

It isn't a question of how, so much as how to do it most efficiently!

Jason

Google: FRC 2008 launcher or maybe FRC Overdrive Launcher and check out the old videos and websites.

Re: How do we launch this thing? 2014

Quote:

Originally Posted by MMahoney (Post 1322010)

I built a quick prototype pneumatic launcher today and was disappointed by how weak it shot. We did a variety of tests at different angles (~10 degrees, 45 degrees, and ~75-80 degrees) and found that the ball flew about 6-7 feet at highest. Barely enough to clear the truss.

One issue with a pneumatic cylinder launcher is the peak piston velocity being restricted by the rate at which air ahead of the piston can exit the cylinder.

Ideally, the space in front of the piston disk seal would be a vacuum, and offer no resistance. This could be accomplished by sealing both ports of the cylinder with the piston extended.

Then by mechanically pulling the piston back into the cylinder so as to build up pressure on one end and partial vacuum on the other piston exit end, you can make it into a "gas spring"
Releasing the hold on the compressed piston would fire it at a higher speed than when there is air ahead of the piston.

This may not be legal though. There are many safety issues. Too much piston retraction could build up pressure in the cylinder exceeding its limits.
Also, piston can overshoot inside cylinder and impact the head at the exit end, damaging it.

-Dick Ledford

Re: How do we launch this thing? 2014

Quote:

Originally Posted by TucoSalamanc (Post 1321978)

Too bad full-field tosses are illegal, because this thing is beastly.

Can you reference a rule that says this?

Re: How do we launch this thing? 2014

Quote:

Originally Posted by Johnson.2937 (Post 1323184)

Can you reference a rule that says this?

Per the scoring section of the manual:

Quote:

A BALL is considered SCORED in an ALLIANCE’S GOAL if

a ROBOT causes one (1) of their ALLIANCE’S BALLS to cross completely through the opening(s) of one (1) of their ALLIANCE’S GOALS without intervening human contact,
the ALLIANCE ROBOT last in contact with the BALL was entirely between the TRUSS and their ALLIANCE’S HIGH GOALS, and
the BALL is not in contact with any ROBOT from that ALLIANCE.

Emphasis mine

Re: How do we launch this thing? 2014

There may be a way to get pistons to work. You guys have only thought about if pistons applied force directly. What if the pistons pulled the ball instead of pushed it? Just a thought:rolleyes:

Re: How do we launch this thing? 2014

I am very interested in seeing this video, could you please link it for us?