KAGRA Logbook

VIS (PR3)

takafumi.ushiba - 7:36 Tuesday 17 March 2020 (13614)

Actuator balancing

Since PR3 actuator balancing doesn't look done yet, I did it.

*****Method*****
I injected 500 counts sin signal at 0.3 Hz on each COILOUTF EXC on TM stage(H1, H2, H3, and H4) and measured the TF from EXC to TM_OPLEV_TILT_YAW_OUT_DQ at excitation frequency.
After that, I calculated the ratio between TFs of H, H2, H3, and H4.
I modified the COILOUTF gain to mitigate the difference of TFs.
I normalized the gain by the largest gain so that the maximum gain is 1.
After this modification, I injected 500 counts sin signal at 0.5 Hz fron TM_TEST_L, TM_TEST_P, and T_TEST_Y.

*****Result*****
Gain ratio; H1:H2:H3:H4 = 0.846:-1:0.628:-0.6
Attachment 1 is TF measurement result and spectra after the gain modification.
Attachment 2 is the latest COILOUTF filter of PR3-TM stage.

Note: XML file is stored at /users/Comissioning/data/VIS/PR3/TM_actuator_DIAG_20200317.xml

Images attached to this report

Comments to this report:

takafumi.ushiba - 8:30 Tuesday 17 March 2020 (13615)

I noticed PR suspension's OpLev is quite large coupling compaired with Type-A's OpLev.
So, I changed the signals used for the balancing from OPLEV_TILT_YAW to OPLEV_YAW_DIAG.

The result will be posted soon.

takafumi.ushiba - 13:10 Tuesday 17 March 2020 (13621)

I did actuator balancing of PR3 TM actuator.
The method is sam but signal used for the balancing is different (This time I used TM_OPLEV_YAW_DIAG_DQ).

*****Result*****

H1:H2:H3:H4 = 0.812:-1:0.796:-0.821
Attachment shows COILOUTF and spectra after this work.

Note: file is om /users/Comissioning/data/VIS/PR3/TM_actuator_DIAG_new_20200317.xml

Images attached to this comment