Calibration of force actuators on an adaptive secondary prototype

TL;DR

This paper details the calibration process of force actuators on an adaptive secondary mirror prototype for the Large Binocular Telescope, achieving high accuracy in force measurement with less than 1.5% error.

Contribution

It introduces calibration procedures for force actuators on a deformable mirror prototype, improving force measurement accuracy for adaptive optics applications.

Findings

Force actuator calibration errors are below 1.5%.

Calibration procedures effectively align driven and measured forces.

Enhanced precision supports adaptive optics corrections.

Abstract

In the context of the Large Binocular Telescope project, we present the results of force actuator calibrations performed on an adaptive secondary prototype called P45, a thin deformable glass with magnets glued onto its back. Electromagnetic actuators, controlled in a closed loop with a system of internal metrology based on capacitive sensors, continuously deform its shape to correct the distortions of the wavefront. Calibrations of the force actuators are needed because of the differences between driven forces and measured forces. We describe the calibration procedures and the results, obtained with errors of less than 1.5%.