Slaving and disabling actuators with voice-coil adaptive mirrors

TL;DR

This paper presents algorithms for re-computing control matrices in voice-coil adaptive mirrors, enabling actuator disabling or slaving without recalibration, demonstrated on large telescope adaptive mirrors.

Contribution

It introduces novel algorithms for matrix re-computation in voice-coil adaptive mirrors that eliminate the need for recalibration when actuators are disabled or slaved.

Findings

Algorithms successfully applied to LBT and VLT adaptive secondary mirrors.

Enables flexible actuator control without recalibration.

Applicable to multiple large telescope adaptive mirror systems.

Abstract

Adaptive mirrors based on voice-coil technology have force actuators with an internal metrology to close a local loop for controlling its shape in position. When actuators are requested to be disabled or slaved, control matrices have to be re-computed. The report describes the algorithms to re-compute the relevant matrixes for controlling of the mirror without the need of recalibration. This is related in particular to MMT, LBT, Magellan, VLT, ELT and GMT adaptive mirrors that use the voice-coil technology. The technique is successfully used in practice with LBT and VLT-UT4 adaptive secondary mirror units.