Ball Launchers? Ideas?

[Anupam Goli]

Originally Posted by burnzkid

We're looking into programming the Kinect to help control an aim-able barrel, depending on distance from the hoop and which hoop we're aiming for.

Quite a noble task! My team is thinking of staying away from Kinect, I'm not entirely comfortable, and I think that for autonomous, there is no better controller than a vision and ultrasonic sensor with a processor on board. We'll see about our main robot design.

[the man]

Originally Posted by Starke

Check out 1771 on FRC Designs Gripper page (See Link Below). This arm used a suction system to grab the ball and then used a device to launch the ball.

http://frc-designs.com/html/grippers.html

Matt

That's sweet. But I want the boots on a kicker / launcher of some kind.

[akoscielski3]

Originally Posted by Tubatroopa

I was actually thinking of a similar system to this. There is no reload time on the shooter so shots can be fired quite quickly.

Careful about saying that there is no reload time. In 2006 our shooter would have to get back up to speed after shooting only a couple balls. You lose a lot of energy when you shoot a ball.

[nighterfighter]

Originally Posted by akoscielski3

Careful about saying that there is no reload time. In 2006 our shooter would have to get back up to speed after shooting only a couple balls. You lose a lot of energy when you shoot a ball.

This is true, but at the most you are only going to be shooting 3 balls at a time.

Unless you have a really well coordinated alliance partner to line them infront of you, then push them into your intake as you shoot...

[the man]

What powered your shooter a CIM?

[robostangs548]

I have it everyone, I just need to figure out how to get my hands on this! http://www.youtube.com/watch?v=aFl-9W8x-uI

[Apeace]

Our team was starting to think about a pnuematic piston that shot-puts the ball through a barrel at the target.

Any suggestions?

[Sean Raia]

I would stray away from that idea. Pneumatics (in my experience) are much better for power than for speed. Maybe use your pneumatics to load a spring?

[the man]

Use smaller diameter cylinders they travel faster. We used them in breakaway with success. The important part was speed not necessarily mass behind the strike. KE = 1/2MV^2 I guess.

[PayneTrain]

Originally Posted by seg9585

As a 2006 FRC participant (Aim High) who built a robot using the pitching machine launcher design, I have a few comments about it:

First off, calibrating the wheels ended up being a little more annoying than expected. Even though we used encoders to measure and even out the speed between each wheel, we found the release angle was still inconsistent -- the balls needed to be squeezed by the wheels a bit to get the traction needed to accelerate the ball, and the balls would end up flinging a bit to the right or left depending on which wheel made contact with the ball first and how the ball re-expanded.
For Aim High this wasn't a big deal because the target was relatively large, but with baskets this year we need a lot more precision.

Also, the ball originally came out without spin, so the balls flew like a knuckleball, making scoring unpredictable. We changed the speed of one wheel to add spin, but then had to apply a directional bias since the spin did induce lift on one side of the ball (still better than a knuckleball)!

Lastly, we had to run those large softball wheels with CIM motors to get them spinning fast enough, but when they were on all match it quickly drained our battery. In later matches we had to turn off the spinner during collection periods just to save power, then wait for the wheels to spin up to speed again.

I did see effective single-wheel launchers against a static surface that took out a lot of the multi-wheel variable issues we had, and they seemed to work well.

Maybe I'm just a little slow in the head after the flow of information today, but why didn't you set up the robot so you could have identical gears underneath the wheels that would allow them to turn at the same rate?

[the man]

I think our ball launcher should have the wheels spinning around 80mph. But that's a rough estimate we'll see what actually happens.

[Sean Raia]

Can you clarify that? Rotational speed typically isnt measured in mph.

[Marc S.]

Originally Posted by the man

I think our ball launcher should have the wheels spinning around 80mph. But that's a rough estimate we'll see what actually happens.

What is 80 mph converted to rpm? Or are you planing on shooting your wheels at a speed of 80mph.

[the man]

Well I estimated what the cim speed would be because I have no idea. I converted it in to mph to make it more easily recognized. But Yeah I have absolutely no idea how fast a cim would actually be spinning but. I took the diameter of the wheel in ft, .5, multiplied it by pi. multiplied it by rpm which I just put in 4500 because I have no idea. Oh yeah the Cim motor would be directly connected to the shaft through the wheels. Then I divided by 60 to give me ft per second. and converted it to mph.

Does any one have any rough ideas as to how fast a cim motor would be spinning under a load of a 6in wheel that is free spinning?

[davidthefat]

This looks cool: http://www.chiefdelphi.com/media/photos/33185