pic: AndyMark Mecanums

[EricH]

Originally Posted by bigboi146

I dont get them. Can you use them in an omni drive. they look awsome though.

See the explanations above. A "mecanum" drivetrain is set up like a four wheel drive with each wheel independently powered. You cannot have two wheels powered by the same motor/tranny. If you do, you will lose all sideways ability, and you may as well go with four wheel drive. There are three teams that I know about that have used this setup in competition. Note: If you tried to use them in a "standard" omni drive (Art's left-hand pic), you would go nowhere, or possibly spin out or fry a motor or something else equally bad. (Actually, mecanum drive is a subset of omni drive.)

[RogerR]

Originally Posted by EricH

See the explanations above. A "mecanum" drivetrain is set up like a four wheel drive with each wheel independently powered. You cannot have two wheels powered by the same motor/tranny. If you do, you will lose all sideways ability, and you may as well go with four wheel drive. There are three teams that I know about that have used this setup in competition. Note: If you tried to use them in a "standard" omni drive (Art's left-hand pic), you would go nowhere, or possibly spin out or fry a motor or something else equally bad. (Actually, mecanum drive is a subset of omni drive.)

actually, in a four wheel omni-drive, if you paired the wheels across from each other together and attached them to a motor, you'd be able to translate freely. unfortunately, this'd mean you would be unable to rotate. i believe you could achieve similar results by pairing the the diagonal wheels on a mecanum drive train together.

[EricH]

Originally Posted by RogerR

actually, in a four wheel omni-drive, if you paired the wheels across from each other together and attached them to a motor, you'd be able to translate freely. unfortunately, this'd mean you would be unable to rotate. i believe you could achieve similar results by pairing the the diagonal wheels on a mecanum drive train together.

Now that I think about it, yes you could, in theory. Again, you could not turn the robot. Also, it might be a bit difficult to link a wheel on the left front corner with the one on the right back corner...

[Simon Strauss]

Originally Posted by EricH

Now that I think about it, yes you could, in theory. Again, you could not turn the robot. Also, it might be a bit difficult to link a wheel on the left front corner with the one on the right back corner...

there are ways, such as elaborate rotating shafts or using tapered gears to angle them the needed degrees then run those together with chain and sprocket with a motor and tranny in the center, would be heavy though.

[EricH]

Originally Posted by nycpunk

there are ways, such as elaborate rotating shafts or using tapered gears to angle them the needed degrees then run those together with chain and sprocket with a motor and tranny in the center, would be heavy though.

And mecanums are heavy enough as it is. We can make some pretty light ones if we want to, but they still weigh at least as much as our six-wheel drive. (if you include trannies on both systems)

[Madison]

Hey Andy,

Is there any chance you could share some general dimensions for these wheels so that those of us who're considering ordering a set can start to work them into our plans? Unless I've missed it elsewhere, it'd be fantastic to know as little as overall diameter and thickness, but if you've got more than that, I'll take it.