mecanum vs. omni

[JesseK]

Originally Posted by dtengineering

We built a mecanum this year... during the six week build period with only a VEX omnidrive holonomic as a practice chassis.

...

You will end up devoting time and resources to the drive that could otherwise go to programming, actuators, and practicing. That said, when you see your team finally get the drive figured out and go drifting past a defender and slam home a tube... or when your grade 12's get to explain the vector mechanics of the mecanum to an experienced adult engineer who has "never seen a wheel like that before"... that is something you won't get from a tank drive.

Jason

This man gets it. It's not about the robots.

I think the point he makes is that even if it sacrifices time and competition success, you have to get your hands dirty or you'll never know for sure.

It is my personal opinion based on what I've seen that mechanum's are better due to traction -- and traction has alot to do with how well your bot drives.

To reduce weight on the mechanum wheel's, you could make custom wheels such as 357's Jester Drive.

Another technical piece that I'd like to know is what kind of power transfer systems do you put on each drive wheel? In Atlanta I saw robots with straight 1:1 drives, 1:5 ratios (or similar) and there was one team that had the 3-speed drill transmissions attached to each mechanum motor, and the Jester Drive CAD shows something like 1:3 connected to 1:3 again.

Also, generally I've seen large-diameter mechanum wheels (are the AM's 6"?), but what is gained or sacrificed in the power and control realm by going to smaller wheels?