Ball Launcher

[Joe_Widen]

What type of material do you suggest to cover the wheel when launching your balls softball style? We've tried a type of rubber/grip thing and it kinda chews up the balls pretty bad. Thanks in advance.

[Shu Song]

That might have to do with how tight the chute for the ball is. If the chute is too tight, the grip will mess up the balls more. Anything more slippery just won't shoot the ball as well.

[Arkorobotics]

smooth rounded metal or change the material of your wheel. And to agree with him ^ you should watch the distance between the wheels.

[Dan Petrovic]

We got a baseball pitching machine to look at today.

When you put the ball in the launcher, and you rotate the wheel by hand, it takes a good amount of force to get that ball through. When the ball reaches the end it pretty much pushes itself out.

You might want to squeeze that ball pretty hard.

[cleonavicius]

You might want to squeeze that ball pretty hard.

We're finding that squeezing it to roughly 5.5-6" between two solid surfaces works fairly well.

[Timmyd]

we found that the pithing machine will deform to about 50% of the balls diameter and that would deform one of the balls we are using

[atomikitten]

I think our softball pitcher wheel is plastic?

[Joe_Widen]

Thanks for the suggedtions, but what tyoe of matierial should we put on our wheels to give it more grip and eventually shooting power?

[Mark Pettit]

We sent the game ball through a 2 wheel volley ball launcher several times. It has a wide flat wheel that was squeezing the ball down less than 1" as it tossed it. It was really consistent in distance, spin, etc. with multiple throws aimed in the same spot. 'Nothing scientific so no real data for you here, but there are a couple of videos (http://faculty.brophyprep.org/robotics/AimHighPage.htm).

[cleonavicius]

I think our softball pitcher wheel is plastic?

No, we are using a 8" pneumatic rubber wheelchair wheel.

The other side is a sheet of acrylic.

[atomikitten]

all right Grumpy McGrumperson. I'll remember to fwd the info to Clingy McClingerson.

[coldabert]

Please keep all posts on topic. The authorities have been notified.

[Rick TYler]

Thanks for the suggedtions, but what tyoe of matierial should we put on our wheels to give it more grip and eventually shooting power?

Joe, I think you got your answer -- the surface matters a lot less than how much the ball is compressed. We've tested with several surfaces and as long as the wheel and and pressure plate are "sticky" enough so that the ball doesn't slide, it doesn't matter. We shredded ball surfaces on our first test machine. When we increased the compression from about 1/4-inch to a little over one inch, the ball damage disappeared and distances improved a lot.

If you want, get some 36-grit sanding belts and glue them around the rim of your wheel. It won't work any better, but it will have lots of friction. You need to be careful, though. If your ball launcher doesn't have enough pressure on the ball, the ball will slip and your high-friction wheels will shred the ball. This may cause your 'bot to be disqualified. Good luck.

[Joe_Widen]

Thanks for everyone's gracious responses, we ended up using the stock wheels and using the dremel to make it look cool and function well, also it gave us a little back spin which makes our ball's arc flatter.

[CraigHickman]

Our team took the large plastic wheels in the kit (the big black ones, dunno the name), and took an angle grinder to the outside to stop it from eating the balls. It works really well when coupled with our full turret and camera. We're happy to announce that we shoot the center goal quite well, even in autonomous.

[Rombus]

our team ended up using the same wheels we made when we first prototyped our shooter. They are aluminum with a kurnled face. We had an issue with balls getting chewed up by them being too close, so we spaced them out a bit and used some rubber bands. Problem was we kept loosing rubber bands!

In the final design, the rubber bands were replaced by o-rings in a groove we turned into the wheel. Now our shooter is damage free, but we do leave catwisker black marks on the balls if we use brand new orings.