Accumulated Lead Error (Positioning Accuracy)

The positioning accuracy depends on errors in six degree of freedom. In a case of a linear positioning stage, the positioning accuracy is influenced by angular error (pitch, yaw, and roll), straightness (vertical and horizontal), and the lead error. Here is defined the positioning error is came from the lead error of screw as one of main reason and it is accumulated when the linear stage moves unidirectional within the full stroke. That's why it is called as "Accumulated Lead Error (ALE)." It is difference between a real output and ideal / calculated input. When the linear stage makes positioning in each position by each commanded values, there is an error between them. It is measured and calculated like following; (Actual displacement) – (Commanded displacement value). The maximum deviation within the full stroke is defined as the ALE.


Accumulated Lead Error