We tried two sets of filters on the output matrix POS column in MC2. Both versions failed. Following are some details.

How test was done:

• PSL shutter was closed and autolocker was switch off.
• Turned off damping on POS, PIT, and YAW using C1:SUS-MC2_SUSPOS_SW2, C1:SUS-MC2_SUSPIT_SW2, and C1:SUS-MC2_SUSYAW_SW2.
• Reference data was taken with no excitation to get relative increase at excitation.
• Channels C1:SUS-MC2_SUSPIT_IN1, C1:SUS-MC2_SUSPOS_IN1, and C1:SUS-MC2_SUSYAW_IN1.
• Frist we sent an excitation through LOCKIN1 at 0.11 Hz and 500 counts amplitude.
• LOCKIN column in MC2 output matrix was kept identical to POS column, so all ones.
• This formed our reference data set when no filters were used. Attachment 1.
• Note that the peak at 0.03 Hz is due to LOCKIN2 that was left switched on due to autolocker.
• Then the calculated filters were loaded using foton. Procedure:
  • Right click on filter bank med. Got to Execute-> Foton.
  • Go to File and uncheck 'Read Only'.
  • Find the filter module name in Module drop down.
  • Select an empty module section in Sections.
  • Write a name for the filter. We used DCcoupF2A and DCcouF2A2 for the two version respectively.
  • Paste the zpk foton format in Command.
  • Check with Bode plot if these are correct filters. Then click on Save. It will take about 30s to become responsive again.
  • GO back to filter bank medm screen and click on 'Load Coefficients'. This should start displaying your new filter module.
  • To switch on the module, click on the button below its name.
• Once fitlers were loaded, we realized we can not use the LOCKIn to excite anymore as it comes as separate excitation.
• So we used awggui to excite C1:SUS-MC2_LSCEXC at 0.11 Hz and 500 counts.
• Then we retook the data and checked if the peaks are visible on PIT and YAW channels and how high they are.

Filer version 1

• This was calculated by starting from ideal output matrix elements as they are currently loaded. All 1's for POS and so on.
• The calculations were done in scripts/SUS/OutMatCalc/coilBalanceDC.py.
• This file uses a state space model of the suspension and calculated the cross-coupling. Then the cross coupling is inverted and applied to the current output matrix elements to get correction DC gains.
• These corrected DC gains are then used to create the filters as described in last post.
• Attachment 2 shows the filter transfer functions and Attachment 3 shows the test results. Failed :(.
• There was practivally no change in cross coupling that we can see.

Filter version 2:

• In this version we used the output matrix optimized at high frequencies earlier (16009).
• While testing this version, we also uploaded this optimised output amtrix at high frequency.
• In this test, we realized the LOCKIN2 was on and switched it off manually. All excitations were done through awggui.
• Attachment 4 shows the filter transfer functions and Attachment 5 shows the test results. Failed :(.
• There was again practivally no change in cross coupling that we can see.

Forgot to upload new MC2 input matrix:

• In hindsight, we should have uploaded our diagonalized suspension input matrix in MC2.
• Without it, there was cross-coupling the in the sensor data to begin with.
• But this can only be part of the reason why all our filters failed miserably.
• Because the output matrix was not diagonalized earlier but it was not so bad. Onyl a fresh test can tell if it was the culprit.