pic: Duodec-Drive (Octocanum)

[dougwilliams]

Originally Posted by AdamHeard

We ripped Aren off and did this too.

3928's design from 2013 is so $@#$@#$@#$@# simple, that it honestly baffles me why anyone would do any variant of butterfly or octonum that isn't a copy of it.

With Andymark's new 4" mecanums, and 4" wide tube, an octonum variant is easy w/ his design.

It's so darn simple.

Does anyone have a picture or link to this approach?

[Madison]

Originally Posted by dougwilliams

Does anyone have a picture or link to this approach?

http://www.teamneutrino.org/seasons/...bot/butterfly/

[Nate Laverdure]

Originally Posted by Madison

http://www.teamneutrino.org/seasons/...bot/butterfly/

Doesn't show the cylinder mounting concept that Aren was talking about.

[AdamHeard]

Originally Posted by Nate Laverdure

Doesn't show the cylinder mounting concept that Aren was talking about.

In absence of finding a picture, that entire module sits inside a 3" wide tube. A 1-1/16" bore cylinder is face mounted to the top of this tube, and pushes down on the standoff above the traction wheel. there is sliding contact, and that is a nonissue.

EDIT: chassis posted here. Holes near ends on top face are where pancake cylinder mounts.

[Aren_Hill]

Uploaded it since it apparently didn't exist on CD.

The piston shown is a 1-1/16" bore pancake piston from Automation direct, 1" stroke. It pushes directly down on a 3/8" steel standoff between the two sideplates of the module, and is not connected in any other way.

The module was spring return default to traction mode by a spring (not shown) attached to the small tab you can see behind the omni.
Pop the spring off and pull a single bolt and you could pull the module out.

Any questions about it just let me know.

-Aren

[bstew]

The CAD for the module has been available for download on http://www.teamneutrino.org/seasons/...bot/butterfly/. You can see how the module works pretty well from it.

[Ryan_Todd]

Originally Posted by Aren_Hill

The piston shown is a 1-1/16" bore pancake piston from Automation direct, 1" stroke. It pushes directly down on a 3/8" steel standoff between the two sideplates of the module, and is not connected in any other way.

The module was spring return default to traction mode by a spring (not shown) attached to the small tab you can see behind the omni.
Pop the spring off and pull a single bolt and you could pull the module out.

Mind blown.

I had only ever viewed butterfly & octocanum drives as a curiosity, but now I'll have to reconsider!

[Ari423]

Originally Posted by Aren_Hill

The piston shown is a 1-1/16" bore pancake piston from Automation direct, 1" stroke. It pushes directly down on a 3/8" steel standoff between the two sideplates of the module, and is not connected in any other way.

The module was spring return default to traction mode by a spring (not shown) attached to the small tab you can see behind the omni.
Pop the spring off and pull a single bolt and you could pull the module out.

Any questions about it just let me know.

-Aren

That is an amazing design! We might be stealing this for next year

[ParkerF]

I would recommend pivoting on the traction wheel unless you have some serious side support. (See Aren's image where the module is snug between the channel.) We had a lot of problems on the 2010 148 drive with this. Your traction wheels will stay put, but the modules will flex sideways under sideloads. We used chains and had issues with them coming off. May not be such a big deal with belts, though.

[Aren_Hill]

Originally Posted by ParkerF

I would recommend pivoting on the traction wheel unless you have some serious side support. (See Aren's image where the module is snug between the channel.) We had a lot of problems on the 2010 148 drive with this. Your traction wheels will stay put, but the modules will flex sideways under sideloads. We used chains and had issues with them coming off. May not be such a big deal with belts, though.

To elaborate on this, the sideplates of this module were .125" thick steel plate, and there were also two pieces of adhesive backed HDPE between the module side plates and the inside tube faces to send the forces straight into the 3x3 tube.

The main reason I chose to pivot on the omni wheel was to keep the CIM hard mounted, rather than swinging with the module (single stage of gearing to the omni wheel).

-Aren