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-   -   pic: 2" Mecanum (http://www.chiefdelphi.com/forums/showthread.php?t=154897)

itsjustmrb 07-02-2017 15:02

pic: 2" Mecanum
 

Max Boord 07-02-2017 15:13

Re: pic: 2" Mecanum
 
Have you guys tested these? I have always wanted to try 3d printing mecanum intake wheels but have not found a design/ filiment combination that I thought would hold up to robot to robot contact.

asid61 07-02-2017 15:15

Re: pic: 2" Mecanum
 
Very cool! I would love to see some durability tests on these just because the material around the rollers looks a bit thin, but for intake purposes they look very capable.

Clayton Summerall 07-02-2017 15:38

Re: pic: 2" Mecanum
 
Where did you buy the rollers? Would you mind sharing the CAD file?

Big-b 07-02-2017 16:14

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by Clayton Summerall (Post 1641704)
Where did you buy the rollers?

It looks like those are printed as well.

Cothron Theiss 07-02-2017 16:20

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by Big-b (Post 1641718)
It looks like those are printed as well.

They actually look injection molded to me, but I might be wrong.

All in all, the look great! I will say, I think you could add a little bit of a fillet to all those interior angles and see some substantial gains in durability. Also, will these wheels ever be outside of your bumpers?

s-neff 07-02-2017 16:53

Re: pic: 2" Mecanum
 
Awesome! What was the manufacturing process for the rollers? Mind sharing the material choice? It's awesome that it looks like you don't have to run a brass sheath on the inner surface.

Are the lock nuts really <1/4" across? I haven't been able to source anything less than 1/4" wide off McMaster, which has made packaging the fasteners difficult. Or do you just accept that the nuts break the plane of the wheel, since it's only an intake for a round game piece?

Clayton Summerall 07-02-2017 18:31

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by Big-b (Post 1641718)
It looks like those are printed as well.

Those look like rubber rollers...

Kevin Sevcik 07-02-2017 21:51

Re: pic: 2" Mecanum
 
If you're printing your own vectored intake wheels anyways, you should totally experiment with the roller angle to see what shoves the balls sideways the fastest. If I'm understanding Ether's mecanum kinematics paper and reasoning correctly (questionable propositions, both) then making the rollers more perpendicular should move the balls sideways faster. Maybe. Completely perpendicular or parallel both obviously fail, so maybe 45 is the fastest, but it just feels like something else should be.

Cothron Theiss 07-02-2017 22:08

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by Kevin Sevcik (Post 1641860)
If you're printing your own vectored intake wheels anyways, you should totally experiment with the roller angle to see what shoves the balls sideways the fastest. If I'm understanding Ether's mecanum kinematics paper and reasoning correctly (questionable propositions, both) then making the rollers more perpendicular should move the balls sideways faster. Maybe. Completely perpendicular or parallel both obviously fail, so maybe 45 is the fastest, but it just feels like something else should be.

Ooh, I like this idea. Do you know of anyone that's made custom mecanums for drive wheels that are anything other than 45°? You could do some really interesting drives that either have more or less power when strafing than usual. Course, they're still a waste of time. But that's beside the point.

itsjustmrb 09-02-2017 14:52

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by Max Boord (Post 1641689)
Have you guys tested these? I have always wanted to try 3d printing mecanum intake wheels but have not found a design/ filiment combination that I thought would hold up to robot to robot contact.

This is the first batch I have printed with the hex bore and they have held up pretty well. The intake is inside the robot this year, so I am an not too concerned.

itsjustmrb 09-02-2017 14:54

Re: pic: 2" Mecanum
 
Quote:

Originally Posted by s-neff (Post 1641736)
Awesome! What was the manufacturing process for the rollers? Mind sharing the material choice? It's awesome that it looks like you don't have to run a brass sheath on the inner surface.

Are the lock nuts really <1/4" across? I haven't been able to source anything less than 1/4" wide off McMaster, which has made packaging the fasteners difficult. Or do you just accept that the nuts break the plane of the wheel, since it's only an intake for a round game piece?

The axles are M3 40mm stainless steel with nylock nuts.


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