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 If my counts are correct, during the official matches 141,077 points were scored, and a minimum of 28,746 frisbees were successfully shot into goals. All without a single decapitation, severed limb, or even one porpoise becoming accidentally entangled in the nets. - dlavery [more] |
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By: BotDesigner
New: 26-07-2016 19:53
Updated: 27-07-2016 16:45
Views: 1102 times
This is my first attempt at designing a WCD setup. Hopefully, there aren't any huge errors in the design.
Specs:
Weight, 32.74lb
Max Theoretical speed, 13 fps
Gear Reduction, 10.71:1
6" VexPro Mecanum wheels
Side rails, 1.5", 1/8" thick square aluminum tubing
Front Rails, 1"x1.5" 1/8" thick rectangular aluminum tubing
The design was inspired by 525's suitcase bot:
https://frcdesigns.com/2013/12/06/be...-suitcase-bot/
Discussion
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27-07-2016 00:42
asid61
Re: pic: Gears in Tube, Mecanum WCD
Nice! what made you go with the 6" mecanums over the 4"?
I like how you've used 1.5" wide tubing. It never gets any love. 
27-07-2016 00:56
snoman
Re: pic: Gears in Tube, Mecanum WCD
Very cool. Good job keep going . Andymark makes something like that as well.
http://www.andymark.com/product-p/am-0688.htm
27-07-2016 00:57
Chak
Re: pic: Gears in Tube, Mecanum WCD
I'm not sure if you can call if a WCD anymore, but nice work anyways.
You can "reverse" the position of the CIM and the wheel in the "gearbox", putting the CIM closer to the center and the mecanum wheel closer to the outside for more stability in the same size.
27-07-2016 08:59
Chris is me
Re: pic: Gears in Tube, Mecanum WCD
I know it's popular on CD these days, but I don't think the gearbox in tube setup here is good. You end up needing a wider tube than necessary to pull it off, adding weight across the entire span of the tube, but the tube is substantially weakened right where strength and rigidity is needed the most - at the wheels. Switching to a larger tube to avoid these big pockets just adds more weight to the setup.
You already are making something out of plate to mount the CIMs to the tube - if you really want as few parts as possible, just make one gearbox half out of plate and use the tube side as the other half of the gearbox. There are reasons not to do this (mainly design flexibility if you change your mind about gearing, admittedly not common) but it does reduce part count and would be similar to your current setup with less weight spent on a tube that's wider than you need.
27-07-2016 09:27
Billfred
Re: pic: Gears in Tube, Mecanum WCD
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Originally Posted by Chris is me
You already are making something out of plate to mount the CIMs to the tube - if you really want as few parts as possible, just make one gearbox half out of plate and use the tube side as the other half of the gearbox. There are reasons not to do this (mainly design flexibility if you change your mind about gearing, admittedly not common) but it does reduce part count and would be similar to your current setup with less weight spent on a tube that's wider than you need.
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So you could still burn in your hole placements without regrets, if you're smart about it.
27-07-2016 10:47
wilsonmw04
Re: pic: Gears in Tube, Mecanum WCD
How are the wheels attached to the output shaft? Would a canter levered design like this be ideal with the lateral loads a mecanum drive experience?
27-07-2016 10:49
ollien
Re: pic: Gears in Tube, Mecanum WCD
The mecanums should be in the tube. Follow the everything-in-tube trend 
Nice work!
27-07-2016 10:55
Chris is me
Re: pic: Gears in Tube, Mecanum WCD
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Originally Posted by wilsonmw04
How are the wheels attached to the output shaft? Would a canter levered design like this be ideal with the lateral loads a mecanum drive experience?
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The only thing to be careful of is, if you use a screw + washer to retain the wheel, make sure those stay tight, because more load is placed on them trying to unthread them.
27-07-2016 10:59
ollien
Re: pic: Gears in Tube, Mecanum WCD
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Originally Posted by Chris is me
Lots of teams ran cantilevered designs like this in 2015 without problems.
The only thing to be careful of is, if you use a screw + washer to retain the wheel, make sure those stay tight, because more load is placed on them trying to unthread them. |
27-07-2016 11:01
Chris is me
Re: pic: Gears in Tube, Mecanum WCD
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Originally Posted by ollien
What would you use other than a screw/washer? I've only heard of WCDs that use them.
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