[Alan Anderson]

The X axis is, as you probably could guess, Axis 1(x). The Y axis is similarly obvious as Axis 2(y). I don't know what third axis you are looking for.

However, the Holonomic drive vi doesn't want Joystick axis inputs. It wants a magnitude (0 to 1), a direction in degrees (0 to 360), and a turn rate (-1 to 1). You can do the Cartesian to polar conversion math yourself, or you can use the "Re/Im to r/theta" complex number vi to turn X and Y axis numbers into a magnitude and direction in radians, then scale the direction appropriately.

An upcoming update to the WPI libraries is supposed to include a version of Holonomic drive that does take Joystick axis inputs more directly.