Here's a quick summary of the Estimator installation from this week (Edgard, Oli, Jeff K, Brian L)
slides with basic info: T2500082
FRS ticket 32526
Installation alogs
Infrastructure installed on HAM2/PR3 and HAM5/SR3, style updates to model, MEDM linked to sitemap - alog 83906
Tools installed in Estimator folder in the SUS SVN alog 83922
We updated the OSEM 10:0.4 calibration filters, but only on SR3 and PR3. alog 83913
Damping filters installed - alog 83926
Tested the fader switch - alog 83982
Designed and installed a blend for SR3 Yaw (DBL_notch in the first filter bank) - alog 84004
Created a new OSEM calibration script - alog 84005
(Edgard is thinking about a general version of this using Python, that is still TBD)
Fitting is well underway, but isn't done yet.
We made much more progress than we expected - thanks Oli and Jeff for all the help. It's not quite ready to go, we need to install the TF fits for the model.
We might have actually been able to test, except the temperature changes from the pumpdown were causing the SR3 optic to move, and the TFs were not very stable. Edgard is working on a log to document this. We have good fits for SR3 yaw taken Friday morning, and we might just try these remotely with Oli's help. We do plan to get a clean set of TFs in a few days when things have stabilized.
-- notes for next steps, thanks to Sheila for this --
We plan to leave the SR3 overall yaw damping gain at -0.5. This means we'll set the 'light damping' to -0.1 and the gain in the estimator to -0.4. Edgard used -0.1 for the fitting, but he notes that the Q's are pretty high so we may need to revisit this.
SR3 oplev channels are : H1:SUS-SR3_M3_OPLEV_{PIT,YAW}_OUT_DQ
Some interesting alogs about the impact of changes to SR damping: alog 72106 and 72130
Elenna's PR3 coherence plots: alog 65495
I've attached a quick spectrum of SR3 yaw and pitch on M3 as seen by the optical lever. It's odd - the yaw looks very lightly damped - but the IFO was in observe. You can not see real motion above the 3.4 ish Hz yaw mode (it should be falling faster that 1/f^6). You might be seeing real motion between the peaks though - and we can use that (peaks at 1, 2.3, 3.4).
(environment was pretty quiet - BLRMS - EQ is 40-100 nm/sec, microseism is 200-400 nm/sec, wind speed below 1 m/s, anthropogenic is 20-30 nm/sec. It's 3 pm Saturday afternoon, local time. )
I've added 2 more plots. The first is to check that the Y damping is on, and it seems to be. This is a spectrum of the Y osem signal. Ignoring seismic input (which is completely fair), the signal here should just be yaw_osem_noise * (1/1-G) (the minus sign assumes you get all the loop gain signs directly from the control). You can see dips at the resonances, so the loop is on, and has some gain, but not much at the 1 Hz mode, more at 3.4 ish Hz. I've also added my yaw noise reference from G2002065 - you can see here that the noise is a bit larger than my estimate above 1 Hz.
LDVW shows that the gain on the M1_DAMP_Y control was already turned down to -0.5 at this time.
Here is a comparison of the spectra of three channels that can be used to monitor the performance of the estimator. We compare the motion when the M0 Yaw damping loop gain is at -0.5, versus when it is at the -0.1 (which is what we are aiming for with the estimator). The equivalent estimator plots should look somewhere in between the purple and blue curves in the images attached.
- The first one is the OPLEV on SR3. If the estimator works, we should be able to see a difference on the mode Qs. The oplev should see that we are able to damp (or control) the modes to the same level as the -0.5 damping.
- The second one is the M1 OSEM spectrum. The closed loop spectrum dips at the resonances of the plant at -0.5 gain (because of the sensitivity function), so we should be able to see that the sensitivity (as seen by the OSEM) is different, but the OPLEV sees good control of the modes.
- The third one is the total drive on M1. We should see that the total drive around the resonances is similar to the drive we get with the -0.5 gain, but the total drive should decrease rapidly above 3 or so Hz. We will need a faster channel than the one shown in the last attachment.
The plan is to make a full list of channels to monitor in conversation with Oli and Jeff, then run a pilot test with the fits from 84041 later in the week.