[EricH]

Originally Posted by Andy Baker

Maybe I am looking at this the wrong way, but shouldn't the wheels be swapped from front to back? Looking at the top view of the robot, I believe the mecanum roller positioning should look like this:

\........../
\........../
\........../
............
............
............
/..........\
/..........\
/..........\

Andy: It depends on the exact application. Mecanums work in either the X configuration or the O configuration. If you have an X on the top, you have an O on the bottom. The bottom side matters the most, naturally.

For the purposes of this discussion, X and O refer to the shape of ground contact. X looks like Andy's picture above; O looks like the following:

/.............\
/.............\
/.............\
...............
...............
...............
\............./
\............./
\............./

Their current configuration is an X pattern on the ground. This provides slightly easier turning. An O pattern would be just as valid, but is slightly (just slightly) worse at turning due to roller angles.

Either pattern works with the same programming, and it's fairly easy to try both. Just swap the wheels front-to-back or side-to-side. Or, in the case of this robot, flip the whole thing over.