pic: 820's finished product

[JKnox]

We are using a holomonic drive with 3 omniwheels. If you're wondering how it works then I can tell you...
The wheels are equidistant from the center of the chassis and are each respectively perpendicular to three lines at 120 degrees. Simply put, each omniwheel is parallel to one of the small side plates on the chassis.
If we want to move in a straight line, since the omniwheels have very little lateral friction, movement is simple vector addition.

\ + / = | ( \ and / being 2 omniwheels and | being the direction)

For instance, if we want to move forwards or backwards in a straight line, the two omniwheels located under the support beams of the arm move at the same rate. If we want to move sideways the vector addition becomes quite a bit trickier as you can imagine. The programming is entirely based on the calculated rates that each of the motors should spin at, but I'm not a programmer so I don't know those details.

As for actual controls for the robot...
We have one joystick for sideways and forward/back movement and when we hold the top button we spin based on the direction and force that we apply to the joystick (left or right).