Meaning
Algorithmic correction represents the primary method for neutralizing angular measurement discrepancies in precision positioning stages. In high-resolution stage systems, abbe error compensation corrects the displacement measurement offset caused by a non-zero distance between the reference line of the measurement instrument and the line of the actual displacement. The offset arises when angular deviations are present during motion.
This mathematical adjustment operates continuously within the motion controller by combining the measured angular change with the known offset distance.
Geometric Relationship
Angular motion in a multi-axis stage amplifies very small tilt angles into errors at the point of interest. When the feedback sensor cannot be co-axially aligned with the payload center, the offset creates a lever arm. This distance determines the magnitude of the displacement inaccuracy.
Controller Execution
Real-time correction utilizes feed-forward loops to dynamically calculate the adjustment values. The motion controller receives high-frequency angular data from secondary sensors. It then adds or subtracts the calculated product from the primary scale reading before executing the next servo step.
This low-latency loop ensures that the commanded position aligns with the actual tool point throughout the path travel.
System Validation
Metrology verification of the adjustment accuracy occurs during final stage characterization using an external interferometer. The calibration process involves collecting positional deviation data across multiple target points under different acceleration profiles. It establishes the limits of the geometric model by revealing residual errors.
The resulting compensation table is permanently written to the non-volatile memory of the controller.
