mecanum wheel postioning

[Ether]

Originally Posted by EricH

Ether, you want to chime in here?

Theoretically, if the wheel pattern is not square then trackwidth and wheelbase lengths should enter into the inverse kinematic computation if you want the rotate command to correspond with actual engineering units:

FrontRight = FWD - STR - K*omega

FrontLeft  = FWD + STR + K*omega

RearLeft   = FWD - STR + K*omega

RearRight  = FWD + STR - K*omega

... where:

FrontRight,FrontLeft,RearLeft,RearRight are wheel tangential speeds, ft/sec

omega is CW rotation around center of area, rad/sec

FWD and STR are driver commands, ft/sec

K is (trackwidth + wheelbase)/2, ft

WPILib and LabVIEW don't support this, so you would have to scale your rotation before calling these methods.

If you don't scale the rotation, it won't cause wheel scrub. It just won't correspond to the rotation you expected.