= Ideas for VIS improvement/upgrade =
== Control ==
 * Inertial control for Type-B
 * Hierarchical control of Type-A
 * Organize tools for commissioners (auto-measurement, safe.snap, etc...)
 * Noise budgeting
 * Feedforward using seismometers
 * Auto health checking system
 * Measurement-based suspension modeling with system identification
 * Optimized feedback based on a cost function
 * Situation-sensitive filter adaptation with peripheral environmental monitors
 * Robust mode for surfing earthquakes without lock loss

== Safety ==
 * Status monitor
 * Better watchdog

== Mechanical Repair ==
 * ETMY GAS filters
 * ETMX F2 GAS
 * ITMX and ITMY F0 GAS
 * ITMY BF Yaw pico
 * BS F0 Yaw stepper
 * PRM IM magnet polarization
 * PR2 TM magnet polarization.
 * Repair of SRM Bottom Filter.
 * Addition of BS Top Filter yaw motor.
 * Replacement of Top Filter thrust bearing.
 * Replacement of ferromagnetic connectors in BS, SR3 and SRM. (So far we don't have a plan to take out SR2 ot of the tank.)
 * Fishing rod repair:
  * SR3 SF: it does not move (klog 8658).
  * SR3 BF: it does not allows us to move the keystone to zero (klog 8658).
  * BS SF: it does not allow us to move the keystone to zero (klog 8645).
  * BS F0: it does not allow us to move the keystone to zero (klog 8645).

== Electrical Repair ==
 * Signal generator cards for LVDT drivers.
 * Renovate unfixed Dsub connections around IP. (Type-A, EY only, [[https://www.dropbox.com/s/iatmy863o6cq7js/Renovate%20EY%20In-vacuum%20cabling.pdf?dl=0|memo]] )
 * (EY) One PTFE cable should be swapped.

== Mechanical Upgrade ==
 * OSTM suspension
 * Jigs for removing the payload part of Type-B/Bp without disassembling everything
 * Rotate the cryopayload of Type A for easy access of the mirror (cleaning, repair, etc)
 * Optical Lever Covers
 * ACCs for inertial damping.
 * New design of GAS filters considering 40kg TM ([[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10148|Memo]]).
 * Add limit swich on vertical fishing rod.[[attachment:FR BF unit_idea.pdf]]
 * For Tyep-A, add a damping system for the 2nd-yaw-mode, where BF is at the node.

== Electrical Upgrade ==
 * Connect the Release-sensor's signal to the digital system. (Type-A, If necessary.)
 * PR3 traverser in-vac cabling

 * [Type-A] add another oplev at MN-stage in order to degenerate P and R coupling.