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Entry  Mon Mar 8 12:01:02 2021, Paco, Anchal, Summary, training, Investigate how-to XARM locking 
    Reply  Mon Mar 8 12:40:35 2021, gautam, Summary, training, Investigate how-to XARM locking 
    Reply  Mon Mar 8 19:22:56 2021, rana, Summary, SUS, IMC suspension characterization 
       Reply  Thu Mar 11 08:13:24 2021, Paco, Anchal, Update, SUS, IMC First Free Swing Test failed due to typo, restarting now 
          Reply  Tue Mar 16 19:13:09 2021, Paco, Anchal, Update, SUS, First success in Input Matric Diagonalization IMC_InputMatrixDiagonalization.pdfInMatCalcScripts.zip
             Reply  Wed Mar 17 11:57:54 2021, Paco, Anchal, Update, SUS, Tested New Input Matrix for MC1 20210317_MC1_InMATtest.pdfMC1_Input_Matrix_Test.tar.gz
                Reply  Wed Mar 17 16:30:46 2021, Anchal, Update, SUS, Normalized Input Matrices plotted better than SURF students IMC_InputMatrixDiagonalization.pdfNewAndOldMatrices.zip
                   Reply  Thu Mar 18 09:18:49 2021, Paco, Anchal, Update, SUS, Testing of new input matrices with new data MC_Optics_Kicked_Time_Series_1.pdfTEST_Input_Matrix_Diagonalization.pdf
                      Reply  Thu Mar 18 12:46:53 2021, rana, Update, SUS, Testing of new input matrices with new data 
                         Reply  Fri Mar 19 10:49:44 2021, Paco, Anchal, Update, SUS, Trying coil actuation balance 
                            Reply  Mon Mar 22 11:57:21 2021, Paco, Anchal, Update, SUS, Trying coil actuation balance 210322_MC1_ASCY.pdfNewandOldMatrices.tar.gz
                               Reply  Mon Mar 22 15:10:00 2021, rana, Update, SUS, Trying coil actuation balance 
                                  Reply  Mon Mar 22 19:07:50 2021, Paco, Anchal, Update, SUS, Trying coil actuation balance 8x
                                     Reply  Tue Mar 23 09:16:42 2021, Paco, Anchal, Update, Computers, Power cycled C1PSL; restored C1PSL MCWFS1and2PITYAW.pdfMCWFS1and2PITYAW_Zoomed.pdf
                                        Reply  Wed Mar 24 09:23:49 2021, Paco, Update, SUS, MC3 new Input Matrix 
                                           Reply  Thu Mar 25 11:46:31 2021, Paco, Anchal, Update, SUS, MC2 Coil Balancing updates CoilActuationBalancing.ipynb.tar.gzMC2_CoilBalancePITnorm_excSamePIT.pdfMC2_CoilBalanceYAWnorm_excSameYAW.pdf20210325_IMC_CoilBalance.tar.gz
                                              Reply  Thu Mar 25 15:31:24 2021, gautam, Update, IOO, WFS servos 
                                              Reply  Fri Mar 26 11:54:37 2021, Paco, Anchal, Update, SUS, MC2 Coil Balancing updates 
                                                 Reply  Mon Mar 29 10:44:51 2021, Paco, Anchal, Update, SUS, MC2 Coil Balancing updates MC2OutMatCrossCouple_Old-to-It3.pdf20210329_MC2_CrossCoupleTest.tar.gz
                                                    Reply  Mon Mar 29 17:11:54 2021, gautam, Update, SUS, MC2 Coil Balancing updates 
                                                       Reply  Mon Mar 29 17:34:52 2021, rana, Update, SUS, MC2 Coil Balancing updates 
                                                          Reply  Wed Mar 31 22:58:32 2021, Anchal, Paco, Update, SUS, MC2 Coil Balancing Test 
                                                             Reply  Thu Apr 1 13:56:49 2021, Anchal, Paco, Update, SUS, MC2 Coil Balancing Test Results SDistanceFromIdentity.pdfSmatIterations.pdfTestingExcitationAlongYAW.pdf
                                                                Reply  Thu Apr 1 18:01:06 2021, Anchal, Paco, Update, SUS, MC2 Coil Balancing Test Results Success?? SDistanceFromIdentity.pdfSmatIterations.pdfMC2CoilCrossCoupling_opt.png
                                                                   Reply  Thu Apr 1 18:48:45 2021, gautam, Update, SUS, MC2 Coil Balancing Test Results Success?? 
                                                                      Reply  Thu Apr 1 21:13:54 2021, Anchal, Update, SUS, Matrix results, new measurement set to trigger 
                                                                         Reply  Fri Apr 2 14:51:20 2021, Anchal, Update, SUS, Bug found, need to redo the balancing 
                                                                            Reply  Tue Apr 6 18:46:36 2021, Anchal, Paco, Update, SUS, Updates on recent efforts FirstMeasurementPlots.pdf
                                                                               Reply  Wed Apr 7 17:38:51 2021, Anchal, Update, SUS, Trying to uncouple only PIT and YAW first SDistanceFromIdentity.pdfSmatIterations.pdfTimeSeriesPlots.pdfCSDPlots.pdfSmatrixPlots.pdf
                                                                                  Reply  Thu Apr 8 17:04:43 2021, Anchal, Paco, Update, SUS, First Successful Coil Balancing SDistanceFromIdentity.pdfSmatIterations.pdfSmatrixPlots.pdf
                                                                                     Reply  Fri Apr 9 13:13:00 2021, Anchal, Paco, Update, SUS, Faster coil balancing SmatIterations.pdfMC2AllOutmat.txt
                                                                                        Reply  Fri Apr 9 17:41:12 2021, rana, Update, SUS, Faster coil balancing 
                                                                                           Reply  Mon Apr 12 10:07:35 2021, Anchal, Update, SUS, What's F2A?? 
                                                                                              Reply  Tue Apr 13 09:51:22 2021, rana, Update, SUS, What's F2A?? 
                                                                                                 Reply  Wed Apr 14 17:53:38 2021, Anchal, Update, SUS, Plan for calculating filter banks for output matrix aka F2A aka F2P MC2propF2A_UL.pdf
                                                                                                    Reply  Thu Apr 15 11:41:43 2021, Anchal, Update, SUS, Proposed filters for output matrix aka F2A aka F2P MC2propPOSfb.pdf
                                                                                                       Reply  Fri Apr 16 11:36:36 2021, Anchal, Paco, Update, SUS, Tested proposed filters for POS colum in MC2 output matrix 20210416_MC2DCcoilBalancingNoFilters.pdfuncFilters.pdf20210416_MC2DCcoilBalancingWithFilters.pdfuncFilters_v2.pdf20210416_MC2DCcoilBalancingWithFilters_v2.pdf
                                                                                                          Reply  Fri Apr 16 15:47:58 2021, rana, Update, SUS, Tested proposed filters for POS colum in MC2 output matrix 
                                                                                                             Reply  Mon Apr 19 12:18:19 2021, Anchal, Paco, Update, SUS, Tested proposed filters for POS colum in MC2 output matrix CrossCoupleTestForEgToCtFilters.pdfuncFilters.pdfuncFilters_v2.pdf
                                                                                                                Reply  Tue Apr 20 10:52:49 2021, Anchal, Paco, Update, SUS, AC gain coil output balancing for IMC POS2PYuncoupled.pdfPIT2PYuncoupled.pdfMC1YAWexc.pdfMC1PITexc.pdf
                                                                                                                   Reply  Tue Apr 20 18:19:30 2021, Anchal, Update, SUS, MC2 coil balanced at DC MC2_DC_Coil_Balanced_St.pngIMC_F2A_Params_MC2.pdfUploadedPOS_F2A_Filters.pdf
                                                                                                                      Reply  Wed Apr 21 11:38:27 2021, Anchal, Paco, Update, SUS, MC2 Damping Gains Optimized MC2_DampGainStepTestWithNewGains.pngMC2_DampGainStepTestWithOldGains.png
                                                                                                                         Reply  Wed Apr 21 15:50:01 2021, Anchal, Paco, Update, SUS, MC2 Suspension Optimization summary 
                                                                                                                            Reply  Wed Apr 21 18:49:29 2021, rana, Update, SUS, MC2 Suspension Optimization summary 
                                                                                                                               Reply  Thu Apr 22 08:50:21 2021, Anchal, Update, SUS, MC2 Suspension Optimization summary 
                                                                                                                            Reply  Mon Apr 26 18:55:39 2021, Anchal, Paco, Update, SUS, MC2 F2A Filters Tested f2a.pdfIMC_F2A_Params_MC2.pdfMC2_F2A_FilterChar_POS2Ang.pdf
                                                                                                                               Reply  Tue Apr 27 10:05:28 2021, Anchal, Paco, Update, SUS, MC1 and MC3 F2A Filters Tested IMC_F2A_Params_MC1.pdfMC1_POStoAng_CrossCoupling.pdfIMC_F2A_Params_MC3.pdfMC3_POStoAng_CrossCoupling.pdf
                                                                                                                                  Reply  Wed Apr 28 10:56:10 2021, Anchal, Paco, Update, SUS, IMC Filters diagnosed 7x
                                                                                                                                     Reply  Wed Apr 28 17:09:11 2021, Anchal, Update, SUS, Tuned Suspension Parameters uploaded for long term behavior monitoring 
                                                                                                                                     Reply  Thu Apr 29 10:52:56 2021, Anchal, Update, SUS, IMC Trans QPD and WFS loops step response test PIT_OFFSET_ON_MC2.pngYAW_STEP_ON_MC2_complete.png
                                                                                                                                        Reply  Thu Apr 29 18:53:33 2021, Anchal, Update, SUS, IMC Suspension Damping Gains Test MC1_SUSDampGainTest.pdfMC2_SUSDampGainTest.pdfMC3_SUSDampGainTest.pdf
                                                                                                                                           Reply  Mon May 3 16:24:14 2021, Anchal, Update, SUS, IMC Suspension Damping Gains Test Repeated with IMC unlocked MC1_SusDampGainTest.pdfMC2_SusDampGainTest.pdfMC3_SusDampGainTest.pdf
                                                                                                                                              Reply  Wed May 5 09:04:47 2021, Anchal, Update, SUS, New IMC Suspension Damping Gains uploaded for long term testing 
                                                                                                                                                 Reply  Wed May 12 11:45:13 2021, Anchal, Paco, Summary, SUS, New IMC Settings are miserable MC_F_Comparison.pdfMC_TRANS_QPD_Comparison.pdfIMC_REFL_DC_Comparison.pdf
                                                                                                                                                    Reply  Wed Jun 2 09:43:30 2021, Anchal, Paco, Summary, SUS, IMC Settings characterization seismicX.pdfseismicXtoMC_F_TFest.pdfseismicXtoMC_TRANS_PIT_TFest.pdfseismicXtoMC_TRANS_YAW_TFest.pdf
                                                                                                                                                       Reply  Wed Jun 2 16:20:59 2021, Anchal, Paco, Summary, SUS, IMC Suspension gains reverted to old values 
                                                                                                                                                 Reply  Sat May 15 14:54:24 2021, gautam, Update, SUS, IMC settings reverted MC2coilOut.png
                                                                                                                                                    Reply  Thu May 20 10:35:57 2021, Anchal, Update, SUS, IMC settings reverted 
                                                                                                                         Reply  Thu Apr 22 12:17:23 2021, Anchal, Paco, Update, SUS, MC1 and MC3 Suspension Optimization Summary 
                                                                                                                            Reply  Thu Apr 22 14:22:39 2021, gautam, Update, SUS, Settings restored MCdamping.png
                                                                                                                               Reply  Thu Apr 22 15:36:54 2021, Anchal, Update, SUS, Settings restored 
                                                                                                                                  Reply  Thu Apr 22 17:04:17 2021, gautam, Update, SUS, Settings restored 
                                                                                        Reply  Sat Apr 10 10:07:47 2021, rana, Update, SUS, Faster coil balancing 
                                                                         Reply  Fri Apr 2 15:22:54 2021, gautam, Update, SUS, Matrix results, new measurement set to trigger 
                                           Reply  Sun Mar 28 14:16:25 2021, Anchal, Summary, SUS, MC3 new Input Matrix not providing stable loop MC3_Input_Matrix_Diagonalization.pdf
                                              Reply  Mon Mar 29 17:07:17 2021, gautam, Summary, SUS, MC3 new Input Matrix not providing stable loop 
                      Reply  Thu Mar 18 13:12:39 2021, gautam, Update, Computer Scripts / Programs, Omnigraffle vs draw.io 
Message ID: 16049     Entry time: Mon Apr 19 12:18:19 2021     In reply to: 16043     Reply to this: 16054
Author: Anchal, Paco 
Type: Update 
Category: SUS 
Subject: Tested proposed filters for POS colum in MC2 output matrix 

The filters were somewhat successful, how much we can see in attachment 1. The tip about difference between eigenmode basis and cartesian basis was the main thing that helped us take data properly. We still used OSEM data but rotated the output from POS, PIT, YAW to x, theta, phi (cartesian basis where x is also measured as angle projected by suspension length).


Eigenmode basis and Cartesian basis:

  • It is important to understand the difference between these two and what channels/sensors read what.
  • Eigenmode basis as the name suggests is the natural basis for the suspended pendulum.
    • It signifies the motion along three independent and orthogonal modes of motion: POS (longitudinal pendulum oscillation), PIT, and YAW.
    • The position of optic can be written in eigenmode basis as three numbers:
      • POS: Angle made by the center of mass of optic with verticle line from suspension point.
      • PIT: Angle made by the optic face with the suspension wires (this is important to note).
      • YAW: Angle made by optic surface with the nominal plane of suspension wires. (the yaw angle basically).
  • Cartesian basis is the lab reference frame.
    • Here we define three variables that can also represent an optic positioned and orientation:
      • x: Angle made by the center of mass of optic with verticle line from suspension point. (Same as POS)
      • \large \theta: Angle made by the optic surface with absolute verticle (z-axis) in lab frame.
      • \large \phi: Twist of the optic around the z-axis. Same as YAW angle above.
  • We want to apply the feedback gains and filters in eigenmode basis because they are a set of known independent modes. (RXA: NOOO!!!!!! read me elog entry on this topic)
  • Hence, the output from input matrix of suspensions comes out at POS, PIT and YAW in the eigenmode basis.
  • However, the sensors of optic positional, and orientation such at MC_F, wave front sensors and optical levers measure it in lab frame and thus in cartesian basis.
  • Essentially, the \large \theta measured by these sensors is different from the PIT calculated using the OSEM sensor data and is related by:
    • \large \theta = PIT - POS, where PIT and POS both are in radians as defined above.
  • When we optimized the cross-coupling in output matrix at high frequencies using the MC_F and WFS data, we actually optimized it In cartesian basis.
  • The three feedback filters from POS, PIT and YAW which carry data in the eigenmode basis need to be rotated into the cartesian basis in the output matrix before application to the coils.
  • The so-called F2A and A2L filters are essentially doing this rotation.
  • Above the resonant frequencies, the PIT and \large \theta become identical. Hence we want our filters to go to unity

The two filter sets:

  • The filters are named Eg2Ctv1 and Eg2Ctv2 on the POS column of MC2 output matrix.
  • This is to signify that these filters convert the POS, PIT, and YAW basis data (eigenmode basis data) into the cartesian basis (x, theta, phi) in which the output matrix is already optimized at higher frequencies.
  • v1 filter used an ideal output matrix during the calculation of filter as described in 16042 (script at scripts/SUS/OutMatCalc/coilBalanceDC.py).
  • Attachment 2 shows these filter transfer functions.
  • v2 filter use the output matrix optimized to reduce cross-coupling amount cartesian basis modes (MC_F, WFS_PIT and WFS_YAW) in 16009.
  • Attachment 3 shows these filter transfer funcitons.
  • Because of this, the v2 filter is different among right and left coils as well. We do see in Attachment 1 that this version of filter helps in reducing POS->YAW coupling too.

Test procedure:

  • We uploaded both the diagonalized input matrix and the diagonalized output matrix as calculated earlier.
  • We measured channels C1:SUS-MC2_SUSPOS_IN1_DQ, C1:SUS-MC2_SUSPIT_IN1_DQ, and C1:SUS-MC2_SUSYAW_IN1_DQ throughout this test.
  • These channels give output in an eigenmode basis (POS, PIT, and YAW) and the rows of the input matrix have some arbitrary normalization.
  • We normalize these channels to have same input matrix normalization as would be for ideal matrix (2 in each row).
  • Then, assuming the UL_SENS, UR_SENS, LR_SENS, and LL_SENS channels that come at input of the input matrix are calibrated in units of um, we calculate the cartesian angles x, theta, phi. for this calculation, we used the distance between coils as 49.4 mm (got it from Koji) and length of suspension as 0.2489 m and offset of suspension points from COM, b = 0.9 mm.
  • Now that we have true measures of angles in cartesian basis, we can use them to understand the effect on cross coupling from the filters we used.
  • PSL shutter is closed and autolocker is disabled. During all data measurements, we switched of suspension damping loops. This would ensure that our low frequency excitation survives for measurement at the measurement channels.
  • We first took reference data with no excitation and no filters for getting a baseline on each channel (dotted curves in Attachment 1).
  • We then send excitation of 0.03 Hz with 500 counts amplitude at C1:SUS-MC2_LSC_EXC and switched on LSC output.
  • One set of data is taken with no filters active (dashed curve in attachment 1).
  • Then two sets of data are taken with the two filters. Each data set was of 500s in length.
  • Welch function is used to take the PSD of data with bin widht of  0.01Hz and 9 averages.

Results:

  • Filter v1 was the most successful in reducing \large x \rightarrow \theta coupling by factor of 17.5.
    • The reduction in \large x \rightarrow \phi coupling was less. By a factor of 1.4.
  • Filter v2 was worse but still did a reduction of \large x \rightarrow \theta coupling by factor of 7.8.
    • The reduction in \large x \rightarrow \phi coupling was better. By a factor of 3.3.

Next, filters in PIT columns too

  • We do have filters calculated for PIT as well.
  • Now that we know how to test these properly, we can test them tomorrow fairly quickly.
  • For the YAW column though, the filters would probably just undo the output matrix optimization as they are derived from ideal transfer function models and ideally there is no coupling between YAW and other DOFs. So maybe, we should skip putting these on.
Attachment 1: CrossCoupleTestForEgToCtFilters.pdf  24 kB  Uploaded Mon Apr 19 13:18:49 2021  | Hide | Hide all
CrossCoupleTestForEgToCtFilters.pdf
Attachment 2: uncFilters.pdf  31 kB  Uploaded Mon Apr 19 16:03:15 2021  | Hide | Hide all
uncFilters.pdf uncFilters.pdf uncFilters.pdf
Attachment 3: uncFilters_v2.pdf  39 kB  Uploaded Mon Apr 19 16:03:49 2021  | Hide | Hide all
uncFilters_v2.pdf uncFilters_v2.pdf uncFilters_v2.pdf
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