8 CIM Modular Octocanum

[brennanvhoek]

We made an octocanum drive train this off season.

Each module contains 1 CIM and 1 mini CIM. The traction wheel is a 4 in by 2 in wide vex traction wheel geared 11:1. The mecanum wheel is a 6 in vex and is geared 7:1. Both axles are live, the mecanum is directly driven and the traction wheel is driven by a belt with a 1.57:1 reduction. Each module weighs aprox. 10lbs. and can be swapped by removing only 5 bolts.

We had it driving this last weekend at Bunny Bots but I unfortunately didn't get any good video. I will try to get some from a team member and post it here later.


https://drive.google.com/file/d/0B6o...it?usp=sharing

https://drive.google.com/file/d/0B6o...it?usp=sharing

https://drive.google.com/file/d/0B6o...it?usp=sharing

Thanks for looking. We would appreciate any feedback.

[Answer42]

Those modules look beautiful, great work. Now that vex has released their 4 inch mechanum wheels I'm sure you could shrink them down quite a bit if you wanted. My only recommendation would be to consider swapping the traction wheels to the outside instead of inside positions. Since traction wheels are what you would most likely use during defense and pushing matches, it's advantageous to have them form the widest drive base possible. This will make your robot much harder to push when you have your traction wheels down. 148 used a similar setup this year with Omni wheels and they were very difficult to play defense on.

[Oblarg]

Looks great!

Your pneumatic cylinder placement is very similar to what 4464 has been working with for our offseason butterfly drive; we were rather uncertain about it, so it's encouraging to see someone else do the same thing.

Any particular reason for having both axles live? I'd think making the axle used as the frame mount dead might give you a nontrivial reduction in friction.