Chief Delphi - pic: Custom Wheels

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- - pic: Custom Wheels (http://www.chiefdelphi.com/forums/showthread.php?t=73386)

Re: pic: Custom Wheels

how well do they grip the balls, thats one issue I've foreseen, is that your flywheels won't impart enough momentum on the balls in the time that they are in contact, do you plan to say wrap them in Velcro?

Re: pic: Custom Wheels

gum roughtop tread works really well, there are other materials also that can grip the balls well. Velcro affects the fabric on the balls, so it's probably not the way to go.

Re: pic: Custom Wheels

Quote:

Originally Posted by XXShadowXX (Post 812615)

They're never going to touch the balls.

We'll use wedge-top or neoprene rubber for traction on the roller surface.

Re: pic: Custom Wheels

Quote:

Originally Posted by Hachiban VIII (Post 812525)

You appear to have misunderstood me when I said "vast quantities of balls very quickly." Think 10 balls in a fraction of a second :D

We actually modeled our shooter using rotational momentum, and imagined that the balls being fired were "collisions" slowing the wheel down. Adding the flywheels greatly improved consistency. Recharge went from about 1 second down to like .2 seconds. Of course we'll have to see about my math :rolleyes:

They weigh 2.5 lbs. each. We know how much the final bot will weigh from CAD and this is a perfectly acceptable amount for us.

I'm curious about your set-up; are you using some sort of clutch system to link these to your 'shooter'? traditional wisdom says that by adding rotating mass, you increase spun-up time (I assume this is what you mean by 'recharge'), though I doubt that an orbit ball would significantly effect the RPMs of these beasts.

Ironically, one of my teams went the exact opposite direction, minimizing roller mass, and instead using the shooting motors themselves to give a high rate of fire.

Re: pic: Custom Wheels

Quote:

Originally Posted by RogerR (Post 812658)

...traditional wisdom says that by adding rotating mass, you increase spun-up time (I assume this is what you mean by 'recharge'), though I doubt that an orbit ball would significantly effect the RPMs of these beasts.

Yes that is correct.

Spin up time will be reduced, but less speed will be lost per shot, so it will be easier to maintain speed.

By constantly spinning the drum slowly we can ramp it up to firing power quickly whenever the need arises.

It is useful to reduce mass from the center of the rotating object, since this mass will not be spinning as fast as that on the edges. This is why we milled out the center. All the mass is on the periphery.

We actually built a very similar dual-ball shooter in '06 that suffered a great deal from recharge. Sitting on top of the ramp, it could only get the first two balls in before it lost speed. :(