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Entry  Fri Jan 30 02:57:03 2015, Jenne, Update, Modern Control, First try with PRCL ASC Wiener filtering 9x
    Reply  Tue Mar 31 22:27:43 2015, Jenne, Update, Modern Control, Preliminary PRMI angular Wiener results PRMI_31Mar2015.pdf
       Reply  Sat Apr 4 17:54:03 2015, rana, Update, Modern Control, Preliminary PRMI angular Wiener results 
       Reply  Tue Apr 21 01:17:13 2015, Jenne, Update, Modern Control, T-240 self-noise propagated through stack and pendulum T240selfnoise.pngLimits.tar.gz
Message ID: 11186     Entry time: Tue Mar 31 22:27:43 2015     In reply to: 10959     Reply to this: 11202   11229
Author: Jenne 
Type: Update 
Category: Modern Control 
Subject: Preliminary PRMI angular Wiener results 

Before locking for the evening, I wanted to try again implementing the Wiener filters that I had designed back in Jaunary (elog 10959). 

The problem then was that the newer version of Quack that I was using was doing weird things to me (elog 10993).  But, tonight I used the old quack3andahalf that we used to use for Wiener-related things, and that worked (for up to order 20 filters).  Actually, the pitch z-axis Wiener filter, when I copy the command string into Foton, says "Error" in the alternate box (the lower one).  I also get this error message if I try to put in filters that were greater than order 20, and have been split into several filters.  I'm not sure what's wrong, so for tonight I'm leaving out the pitch z-axis seismometer feed forward, and only using 20th order filters for all the rest.

So, pitch has feed forward signals from the T-240's x and y axes, and yaw has feed forward signals from all 3 seismometer channels.

At first, I just had the calculated Wiener filters, and a 10Hz lowpass, but the POP beam spot on the camera was getting slowly pushed away from the starting location.  So, I added a 0.01Hz cheby1 highpass filter, and that seems to have fixed that problem.  I need to go back to the simulations though, and see if this is going to cause extra noise to be injected (because of incorrect phase in the feed forward signal) at very low frequencies.  All 5 Wiener filter banks have a gain of -1.

I'm getting a factor of 4-5ish between 2Hz and 3Hz in both pitch and yaw.  What's interesting is that despite no direct angular suppression (as measured by the QPD) at higher frequencies, both POP22 and POPDC see improvement over a much broader range of frequencies.  I'll have to think about how to predict this RIN coupling in my budgets.

The time series data for these filters was collected 2 months ago, on the 29th of January.  So, it's nice to see that they work now too (although we have already seen that length feed forward signals are good over a many-month period).   

In uncalibrated units (I need to calibrate the QPD to microrad, and should probably quote the PD signals in RIN), here is the plot.  Blue trace (taken first) was with the feed forward on. Red trace (taken immediately afterward) was with feed forward off. This data is all PRMI-only, locked on REFL165 using Koji's recipe from elog 11174, including changing REFL165 phase to -14deg (from the -110 I found it at) for the no-arms case.

PRMI_31Mar2015.pdf

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