aLIGO LHO Logbook

H1 SUS (CAL, DetChar, ISC)

jeffrey.kissel@LIGO.ORG - posted 16:31, Tuesday 09 June 2015 - last comment - 13:49, Tuesday 16 June 2015(19018)

Dynamical Model of the QUAD Tagged Before Update for Future Reference

J. Kissel

In preparation for updating LHO's local copy of the QUAD model to receive all of Brett's new goodness (see LHO aLOGs 18987 and 18809), I've tagged the current SUS model that has been used for recent calibration studies for ER7. The tagged model lives here:
/ligo/svncommon/SusSVN/sus/trunk/Common/SusModelTags/Matlab/quadmodelproduction-rev7508_ssmake4pv2eMB5f_fiber-rev3601_fiber-rev7392_released-2015-06-09.mat.

Details:
--------
The tag was created using the following script:
/ligo/svncommon/SusSVN/sus/trunk/Common/MatlabTools/tagsusdynamicalmodel.m rev7650

The parameter set used,
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Production/quadopt_fiber.m rev3602
are the parameters that have been originally fit to match H1 SUS ETMY's M0-to-M0 (TOP to TOP) transfer functions, but used generically for all quads. It does *not* however include the "correct" frequencies of the violin modes as measured from H1 SUS ETMY (this is half the reason for the update).

The filters for local damping loops wrapped around the dynamical model were grabbed directly from the following foton filter file
/opt/rtcds/lho/h1/chans/filter_archive/h1susetmy/H1SUSETMY_1116978122.txt,
HOWEVER, *which* filter module was used and the damping loop *gains* (i.e. the EPICs settings) were hard-coded to a value that Brett captured a few months ago:
loading M0_DAMP_L with module #s: 1 2 3 5 10.
loading M0_DAMP_T with module #s: 1 2 5 10.
loading M0_DAMP_V with module #s: 1 2 5 10.
loading M0_DAMP_R with module #s: 1 2 5 10.
loading M0_DAMP_P with module #s: 1 3 5 6 10.
loading M0_DAMP_Y with module #s: 1 2 3 5 6 10.
with a gain of -1.17. This is different from the current typical gain of -1.0 (except for pitch which is -3.0), so all DOFs are slightly over damped, except pitch which is under damped.

Comments related to this report

brett.shapiro@LIGO.ORG - 16:50, Tuesday 09 June 2015 (19035)

Link

Jeff, you should also tag

makequad_with_modal_fibers.m (same directory)

This is the function that the generate script calls to add violin modes. It has also changed (a couple of times in the past couple weeks).

Just to clarify, because I don't think I said in any other log, the quadopt_fiber.m parameter file is unchanged in all these updqates. Any custom changes for particular suspensions are meant to be applied to new parameter files now on the SVN:

h1etmy.m, h1etmx.m, h1itmy.m, h1itmx.m, l1etmy.m, etc.

Currently all these custom quad parameter files are direct copies from quadopt_fiber.m. They are intended to be updated with measurements at some point. h1etmy.m differs only in that the measured violin modes from H1ETMY are included (first 8 modes).

Incidentally, quadopt_fiber.m was created by fitting it to H1ETMY data (as a representative case). Not just M0 to M0 TF data, but the single, double, and triple hang resonances were used too. Also, the measured mass values of the 4 stages are included. Therefore, h1etmy.m may be considered 'complete' in that it is already customized for H1ETMY, simply because quadopt_fiber.m was. The other files are just place holders for the other suspensions currently.

Previously, in log 18809 the violin modes for H1ETMY were hardcoded in the generate scripts. Now that we have customized parameter files, the violin modes have been moved into those.
So, unless you call the generate script with a custom parameter file, you will simply get the modeled modes.

jeffrey.kissel@LIGO.ORG - 13:49, Tuesday 16 June 2015 (19172)CAL

Link

This purpose of these tags is to document the QUAD model that was used in the DARM calibration models circa ER7 (see LHO aLOG 18769). I have *not* yet updated the local copy of the repository to absorb all of Brett's recent work on improving the model (in fact, I really *want* to start using those improvements, which is why I need to make sure the calibration model for ER7 does not depend on the new-ness, and uses these tagged versions). So, yes, eventually, after I svn up the local LHO copy of the quad model directory, I will make new, additional, tagged version of the model, but for now the focus is preserving what we had *before* these upgrades that Brett mentions in his comment.

This being said, the ability to add violin modes to the model (albiet with in-accurate frequencies), has been around for a while. As such, I did use the first 25 violin modes modeled with viscous damping in the DARM calibration model. HOWEVER, the above mentioned tagging function did not include the violin modes (i.e. it didn't give generate_QUAD_Model_Production enough inputs) because that script pre-dates the addition of violin modes, and I forgot.

So in the same place as described in my above aLOG, I've
(1) changed the name of the above mentioned 2015-06-09 tag to reflect that it is with NO violin mode damping (which may still be useful to people):
/ligo/svncommon/SusSVN/sus/trunk/Common/SusModelTags/Matlab/
quadmodelproduction-rev7508_ssmake4pv2eMB5f_fiber-rev3601_fiber-rev7392_NOviolinmodes_released-2015-06-09.mat, 
and
(2) tagged a new version of the model WITH violin modes:
/ligo/svncommon/SusSVN/sus/trunk/Common/SusModelTags/Matlab/
quadmodelproduction-rev7508_ssmake4pv2eMB5f_fiber-rev3601_fiber-rev7392_WITHviolinmodes_released-2015-06-16.mat

Again -- BOTH OF THESE TAGS STILL HAVE INCORRECT LOCAL DAMPING LOOP GAINS, as mentioned above.