Turning With Mecanum Wheels

[technik3k]

This is more accurate diagram, because it clearly indicates “Top View” and force vectors are drawn for the case of turning:

@technik3k

and another one for the robot turning clockwise:

Depending on the amount of friction you have in all your bearings you could easily need 1.5 times more motors just to keep up with the simple non-holonomic “tank” drive. (It is actually tricky because extra friction in the rollers themselves favors forward-backward movement vs. sideways movement).

There is more information in the linked topic, but TLDR is that Mecanum wheels will exert large forces inline with axles onto the wheel bearings. If you don’t have well lubricated teflon washers between wheels and bearings, then you are going to have a bumpy ride with a lot of power losses due to friction.

Also, Mecanum wheels only make sense for heavier robots, because of the way they convert robot weight into forward traction. Only use them if your gameplay calls for a slow heavy robot that needs to move sideways without much turning.