pic: Rookie Testing Platform

[Alan Anderson]

Originally Posted by ubermeister

You can't turn under power with X on the bottom. All the force that would be turning the robot is redirected by the rollers into an X pattern rather than an O pattern. So the robot is really pushing inwards on itself when it tries to turn, rather than pushing itself around.

If your mecanum wheels are placed in a rectangle rather than a perfect square, you actually can manage to turn if they're installed with the wrong orientation. The vectors won't all cancel completely unless all the roller axes intersect at a single point.

They still cancel to a large extent, and it still doesn't turn very well.

The proper configuration has the rollers angled so that each of the wheels could move freely in a direction toward or away from the center of the robot without the wheel itself turning.