How Do Mecanum Wheels Work?

[SPARKY1688]

Hey guys, I wanted to know if anyone knew exactly how mecanum wheels work. How would the wheels have to be propelled in order to move side to side, foward and backwards, and still turn 360 degrees.
thanks,

Marko,1688

[zander_108]

Hey guys, I wanted to know if anyone knew exactly how mecanum wheels work. How would the wheels have to be propelled in order to move side to side, foward and backwards, and still turn 360 degrees.
thanks,

Marko,1688

lets say these numbers represent the wheels, the top being the front


1______2
________
________
________
________
3______4



to go forward or backwards rotate 1 and 3 opposite of 2 and 4.

to go side to side, have 1 and 2 rotate in opposite direction to 3 and 4

to rotate in place, all same direction.

[EricH]

lets say these numbers represent the wheels, the top being the front


1______2
________
________
________
________
3______4



to go forward or backwards rotate 1 and 3 opposite of 2 and 4.

to go side to side, have 1 and 2 rotate in opposite direction to 3 and 4

to rotate in place, all same direction.It's actually (using above diagram):
Forwards/backwards: all wheels same direction (as with tank steering)
Rotate in place: 1 and 3 one way, 2 and 4 the other.
Side to side: 1 and 4 one way, 2 and 3 the other.
We've done experiments with these, and this is how we did it.

[zander_108]

I meant with the type of mecanum where the wheels face out from the center, at the corners, where the axis of the wheels are perpendicular... sorry for the missunderstanding.

[EricH]

I meant with the type of mecanun where the wheels face out from the center, at the corners... sorry for the missunderstanding.That's actually better known as an omni drive.
For more information, this thread (http://www.chiefdelphi.com/forums/showthread.php?t=36079&highlight=mecanum) discusses one of the best mecanum drivetrains out there. The sides may be mirrored, which will not really affect directions (other than side to side)

[Lil' Lavery]

Through the angeled rollers, a Mecanum wheel diverts the force of the wheel into a different direction. The resultant force of the wheel depends on the angle of the rollers (which is typically 45deg).


For more detailed info, consult the following:
http://www.araa.asn.au/acra/acra2002/Papers/Diegel-Badve-Bright-Potgieter-Tlale.pdf
http://www.chiefdelphi.com/media/papers/1836

[zander_108]

That's actually better known as an omni drive.
For more information, this thread (http://www.chiefdelphi.com/forums/showthread.php?t=36079&highlight=mecanum) discusses one of the best mecanum drivetrains out there. The sides may be mirrored, which will not really affect directions (other than side to side)

I acctually meant somewhat like this robot (http://www.chiefdelphi.com/media/photos/25311)

[SPARKY1688]

Quick response thanks alot big help
marko

[Lil' Lavery]

I acctually meant somewhat like this robot (http://www.chiefdelphi.com/media/photos/25311)

That is a Holonomic drive. Holonomic platforms are not the same as Mecanum, although both allow for movement in all planar directions, rotation, and near-instant change of direction.

[COACHTJ1688]

Thanks for the info guys. We appreciate it.