Positional Accuracy:
The maximum error between the expected position and the position
actually achieved by the motion of the system.
Positional Repeatability:
Tolerance within which a positioner returns to an exact
location.
Straight Line and Flatness Accuracy:
This is the amount of deviation from the ideal straight line of
travel. Straight line accuracy is the deviation in the horizontal plane, while
flatness is the deviation in the vertical plane