Chief Delphi - Prototype Small Wheeled Shooter

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Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Robot Showcase (http://www.chiefdelphi.com/forums/forumdisplay.php?f=58)

- - Prototype Small Wheeled Shooter (http://www.chiefdelphi.com/forums/showthread.php?t=111360)

JVN	25-01-2013 12:11

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by Kevin Sevcik (Post 1221611)

To be more precise, there are two ball bearings on the output shaft and one (I think, don't have one in front of me) on the input side holding the input coupling. So the output shaft can definitely support some cantilevered loads.

Do remember that you're not going to be able to stick a mini-cim into this gearbox. You'll have to go with a BAG motor and a 3:1 ratio, which will endup somewhat slower than your mini-cim. So you might be better off figuring out how to make up a shaft coupling and support system for the mini-cim.

EDIT:Actually, a BaneBots RS550 motor into a 3:1 gearbox gets you a similar free speed to the mini-CIM with a bit more power. You might try that combo as a drop-in replacement for your mini-CIM.

If you're clever, with a custom mount plate and a trimmed down shaft, you can mount a MiniCIM to a VersaPlanetary gearbox.

-John

brianwech

25-01-2013 14:21

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by falconmaster (Post 1221334)

Thanks Team Spectrum!
We have one now
http://www.youtube.com/watch?v=zggvD...ature=youtu.be

I'd love to hear more regarding details of your shooter: motors, gear boxes, gear ratios, wheels, voltage to motors, distance between wheels, etc. Thanks.

AllenGregoryIV

25-01-2013 15:04

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by JVN (Post 1221654)

If you're clever, with a custom mount plate and a trimmed down shaft, you can mount a MiniCIM to a VersaPlanetary gearbox.

-John

I can't believe I didn't notice it was an 8mm hole until you said that.
I know what we're playing with next week. (Note: Not for our shooter)

Kevin Sevcik

25-01-2013 15:18

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by AllenGregoryIV (Post 1221745)

I can't believe I didn't notice it was an 8mm hole until you said that.
I know what we're playing with next week. (Note: Not for our shooter)

*blinks* So that's what that "notch" is in there for. Or so you'd hope. I wouldn't want to pin my hopes on that set screw in the CIM keyway.

Also, I have a feeling a mini-CIM would really push the limits on the load rating of the VersaPlanetary. And if you swapped a CIM in instead... Well that'd be extremely exciting.

JVN	25-01-2013 15:50

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by Kevin Sevcik (Post 1221753)

Also, I have a feeling a mini-CIM would really push the limits on the load rating of the VersaPlanetary. And if you swapped a CIM in instead... Well that'd be extremely exciting.

Depends entirely on the reduction, and output shaft configuration. Check out the loading tables at the end of this guide:
http://content.vexrobotics.com/vexpr...s_20130107.pdf

AllenGregoryIV

25-01-2013 16:32

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by JVN (Post 1221775)

Depends entirely on the reduction, and output shaft configuration. Check out the loading tables at the end of this guide:
http://content.vexrobotics.com/vexpr...s_20130107.pdf

I should have pictures up in the next hour or two. I have a student doing it right now.

AllenGregoryIV

25-01-2013 17:30

Re: Prototype Small Wheeled Shooter

Instructions are up on our blog

http://3847.blogspot.com/2013/01/ver...-mounting.html

This was a pretty simple conversion. We cut the shaft more than would most likely be recommended but that lets you directly mount it to the Versplanetary with out any adapter plate.

Alex Cormier

25-01-2013 17:35

Re: Prototype Small Wheeled Shooter

I don't recall but, do you have any video of shooting with the disc upside down?

AllenGregoryIV

25-01-2013 17:42

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by Alex Cormier (Post 1221841)

I don't recall but, do you have any video of shooting with the disc upside down?

Not from this prototype, it needs some sort of cap over the wheels to get long shots with upside down discs (think the C channel from robot in 3 days), otherwise we find that the discs rise up out of the wheels before they leave the shooter.

Kevin Sevcik

25-01-2013 17:43

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by JVN (Post 1221775)

Depends entirely on the reduction, and output shaft configuration. Check out the loading tables at the end of this guide:
http://content.vexrobotics.com/vexpr...s_20130107.pdf

I stand corrected. If you're willing to green light a 1/2" hex shaft 300:1 BAG Motor for simple loading, that's the equivalent of a 1/2" hex shaft 50:1 big CIM motor. Which at 90 ft-lbs stall and nothing to sneeze at.

Allen,
Are the black spacers for standing off an AM-9015 motor too small to stand off the CIM?

AllenGregoryIV

25-01-2013 17:46

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by Kevin Sevcik (Post 1221845)

Allen,
Are the black spacers for standing off an AM-9015 motor too small to stand off the CIM?

Didn't think about it but that does work. That will add back a 1/4in to the shaft.

falconmaster

25-01-2013 20:18

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by AllenGregoryIV (Post 1216340)

We just posted a blog entry about our current prototype shooter. It uses much smaller diameter wheels than many teams that we have seen post of CD. We're hoping this idea might inspire some teams that are struggling to package their large shooters.

Blog Entry with full specs on the shooter configuration.

Youtube Video

Hello guys, Nice job! We are experimenting with your setup and are having some degree of success. We have about 10 3/8 compression gap or 5/8 compression and we find the frisbee shoots straightest when the angle on the side ends with it being inline with the center of the last wheel. We do see that it goes straight , but if we make it a 1/4' longer it goes farther but not quite as straight. We also tried the gap between the two wheels at 1/4 " and with the centers 2" apart. It seems that the closer the wheels the farther it goes. We had the first wheel at 5K and the second wheel at 15k. Could you share your settings that worked best for you? Thanks. Again awesome job!

AllenGregoryIV

25-01-2013 20:31

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by falconmaster (Post 1221916)

We're nearly identical to that. BAG motors 1:1 and 1:3 wheels close together and the wall ending at the center of the fast wheel. Compression at about 1/2 inch. You have just verified our settings.

Ether

25-01-2013 20:44

Re: Prototype Small Wheeled Shooter

I'd like to hear from teams -- if there are any -- who been successful spinning the 2nd wheel approx 30% to 40% faster than the second wheel, instead of 3x as fast.

AllenGregoryIV

25-01-2013 21:17

Re: Prototype Small Wheeled Shooter

Quote:

Originally Posted by Ether (Post 1221924)

I'd like to hear from teams -- if there are any -- who been successful spinning the 2nd wheel approx 30% to 40% faster than the second wheel, instead of 3x as fast.

Do you have any reason to assume that is more optimal? We would like to know.

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