Check actuator coupling ratio at IP stage for Xarm suspensions

[YoshinoriFujii]

Background

• It was found that there was couplings from ITMX-IPT and ITMX-IPY motion to Xarm cavity signal,

Todo

• [X] measure mechanical TFs of:

  • [X] ETMX
  • [X] ITMX

• [ ] compare how the coupling ratio is same:

[YoshinoriFujii]

2019.9.29

Before:

• ETMX: /users/VIS/TypeA/general/LogNotes/20190929/ETMX/maechanical_coupling

• ITMX: /users/VIS/TypeA/general/LogNotes/20190929/ITMX/maechanical_coupling

  • see for the measurement files of this diagonalization work for ITMX: /users/VIS/TypeA/ITMX/actuator_diag/IP_LVDT/20190929/

symptom:

• In ITMX, LtoT coupling was relatively large at 0.1Hz, compared to that of ETMX.
• TtoL, Yto_the-others, it looked that there was not much (terrible) differences between ETMX and ITMX.

---

After:

• After working 2Hz diagonalization work,

• Comparison: before vs. after diag.

• It was found that there was not differences.

---

• [x] try 0.1Hz iagonalization

[YoshinoriFujii]

try 0.1Hz diagonalization

• see /users/VIS/TypeA/ITMX/actuator_diag/IP_LVDT/20190930/

• The result was:

  D =
  2.6897   -0.2661    0.7587
  -1.4823   -1.9867    0.5643
  -1.1332    2.2866    0.6682

  ---

• the mechanical (actuator coupling) was following:

• see /users/VISsvn/TypeAtower/ITMX/Measurements/20190930/after_0.1Hz_diag/

• IPLexc

• IPTexc

• IPYexc

---

• A bit improved? especially from Yaw?
• But not much improved from L and T.
• Also, Q in IPT2IPT looks relatively small?

[YoshinoriFujii]

see https://github.com/YoshinoriFujii/Weekly-task/issues/32 for Y-arm suspensions.

[YoshinoriFujii]

• [ ] Try make new actuator matrix using the coupling at 0.1Hz?