= Angular Sensing and Control (Oct, 2022) =

<<TableOfContents()>>

== WFS ports ==

=== REFL (17, 45 MHz) ===
 * Optical layout
  * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9238
  * Same as O3GK
 * PZT1, PZT2, and REFL_WFS picomotors are available to center the beam on REFL_WFS1 and REFL_WFS2
 * Phasing is done by Kenta


=== POP (17, 45 MHz) ===
 * Optical layout
  * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9623
  * POP WFSs were newly installed after O3GK
 * POP-S and POP-P cameras are available
 * Phasing is done by Kenta

=== AS (17, 28 MHz) ===
 * Optical layout
  * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9817
  * Mostly same as O3GK
 * PZT1, PZT2, and AS_WFS picomotors are available to center the beam on AS_WFS1 and AS_WFS2
 * AS and OMC_TRANS CCDs are available
 * OMC_REFL CCD hasn't been connected
 * Phasing is done by Kenta in June

== DC QPD ports ==


=== TMSX ===
 * There is only QPD2 ({{{K1:TMS-X_IR_QPDA2_{PIT,YAW} }}}) on the TMSX in-air path. At a random Gouy phase position.
 * The beam was sent to the QPD2 when the X-arm is locked, but the X-arm alignment may have changed since then.
 * TMSX in-air table power budget
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22310
 * The in-air beam is extremely astigmatic
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22221
 * There are strong PIT-YAW coupling depending on the position of the beam
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22228
  * Matteo-san's previous measurement did not show a strong coupling. It seems to depend on the position of the DC QPDs.
   * https://klog.icrr.u-tokyo.ac.jp/osl/?r=20263
  * Is the TMSX in-air beam clipped in the TMS in-vac?
   * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22762


=== TMSY ===
 * TMSY QPD1 and 2 are placed on the TMSY in-air table, with 90 degrees separated in Gouy phase
 * QPD1 is used to the beam position control feeding back to the BS ({{{K1:ASC-DOF1_{P,Y} }}})
 * Beam profile
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22479
 * No PIT-YAW coupling 
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22575

=== POP Forward ===
 * There are two DC QPDs on POP Forward, used for the initial alignment
  * {{{K1:ASC-POP_FORWARD_QPDA1_DC_{PIT,YAW} }}}
  * They can be found on sitemap > ASC overview > All DC QPDs

== DC PDs ==
 * There are POP_P and POP_S DC PDs on POP.
  *  {{{K1:LSC-POP_S{P}POL_DC}}}
  * Can anyone add them on an MEDM screen somewhere?

== WFS Commissioning ==


=== WFS DC centering ===
==== General ====
 * Beam spots on the quadrant diodes must be centered (DC centering)
 * If the beam is off from the WFSs, use the picomotors first because the PZT ranges are not large
 * {{{K1:ASC-DC{5,6,7}_{P,Y} }}} are to be used for the WFS DC centering loops
==== REFL ====
 * Open the REFL shutter first for REFL WFS 
 * {{{K1:ASC-DC5_{P,Y} }}} are used for the DC centering controls
  * FM filters:
   * Gains: null (gain of 0) and Gain(UGF40)
   * LPF: p1 (pole at 1 Hz)
   * Integrator: p0:z1 (pole at 0 Hz, zero at 1 Hz) - turn this on after the LPF
==== POP ====
 * DC control loop not implemented yet
==== AS ====
 * DC control loop not implemented yet


=== Single Y arm ===
 * Sensing matrix
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22578
 * Input matrix
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22602
 * Output matrix
  * {{{K1:ASC-DSOFT_{P,Y} }}} to IY
  * {{{K1:ASC-DHARD_{P,Y} }}} to EY
 * Loops closed
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22671
 * Loops or noise haven't been characterized
 * No offsets were necessary on the sensors


=== Single X arm ===


=== PRMI ===


=== PRFPMI ===

=== DRFPMI ===

= Next Steps =
== Infrastructure ==
 * Guardian implementation
  * DC centering loops on REFL, POP, and AS
  * Single Y, X arms, and PRMI guardstates for initial alignment
 * Add trigger for the main ASC switch ({{{K1:ASC-WFS_GAIN}}}) similarly to the IMC switch ({{{K1:IMC-WFS_GAIN}}})
== Simulation ==
 * Compare the measured sensing matrices against the simulation
  * Koyama-kun's simulation GUI tool is available on the workstations
   * sitemap > Commissioning Top > finesse GUI
== Integration ==
 * Implement single-Y, single-X, and PRMI controls for the initial alignment
  * If the alignment is too off, first ADS then WFS control?
 * PRFPMI/DRFPMI angular controls
 * Noise budget

= Known issues =
 * TMSX PIT-YAW coupling
  * The beam is slightly not centered in yaw on the second lens on the in-air table. Adjusting the beam position on the lens might fix the problem.