40m
QIL
Cryo_Lab
CTN
SUS_Lab
TCS_Lab
OMC_Lab
CRIME_Lab
FEA
ENG_Labs
OptContFac
Mariner
WBEEShop

40m Log 
Not logged in 


Message ID: 202
Entry time: Wed Dec 19 16:07:37 2007

Author: 
Andrey 
Type: 
Summary 
Category: 
Computer Scripts / Programs 
Subject: 
Results of overnight measurements Tue/Wed night (entry #198) 


As indicated in ELOG entry 198, I was making overnight measurements during last night from Tuesday to Wednesday.
I was changing the suspension damping gain in ETMX and ITMX in "position" degree of freedom between values of 1.00 and 4.50 with the step 0.25.
Results for RMS of peaks (A) at 0.8Hz, (B) at about 3.0Hz and (C) in the range from 0.6Hz to 3.7Hz ("RMS in a broad interval") are given below:
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}Q_{ETMX}) > first three graphs (attachments 1 3);
2) view from the side in the same sum and differenceaxes > next three graphs (attachments 46);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes > next three graphs (attachments 79)
Attachments 10 and 11 show ratios of accelerometer signals at different times of the night/morning.
A little discussion about these graphs:
1) The areas of minima and of rapid growth are the same for all the measurements during all three nights.
2) Tonight there was a strange spike for the values of Q_{ETMX}=2.5 and Q_{ITMX}=4.0. I interpret that as an error of experiment.
3) On all the plots from all three nights there is a wide area of minimum on the plots for RMS at 0.8Hz and for "RMS in the broad interval",
and the graph for "RMS at 3Hz" indicates a clearer minimum in a localized area for Q_{ITMX}=2+1, Q_{ETMX}=2+1. Note that this area 2+1
is included into the wide region of minimum for "RMS at 0.8Hz" and "RMS in a broad range".
Therefore, my guess at this stage is that we can choose the optimized value of suspension damping gains for both Q_{ITMX} and Q_{ETMX} somewhere
around 2+1. I would like to make another overnight measurement (tonight) in that narrowed region with a small step to have more certainty.
By the way, I realized that I was a little bit careless and at some plots Q_I stands for {Q_ITMX}, and Q_E stands for Q_{ETMX}.






















