Optimal control of the ARM alignment with digital compensation of the Sidles-Sigg radiation torque

Document #:

LIGO-T1800077-v4

Document type:

T - Technical notes

Abstract:

We apply the optimal control techniques (H-infinity and mu-syntheses) to align the aLIGO arm cavity. For the soft mode, it can be further combined with the digital subtraction of the Sidles-Sigg torque so only one set of filters is needed for different input power levels.

We show that our scheme can simultaneously improve the low-frequency rms motion and the high-frequency sensing noise. Moreover, the controller is robust under typical fluctuations in the arm power and/or sensing gain.

Files in Document:

• GWADW_18 (OptCtrl.pdf, file is not accessible)

Other Files:

• ASCnoise.pdf (file is not accessible)

Topics:

• Detector

Authors:

• Hang Yu
• Denis Martynov
• Lee McCuller

Associated with Events:

GWADW 2018 held from 12 May 2018 to 17 May 2018