Control of the KAGRA Cryogenic Vibration Isolation System Koki Okutomi Sokendai / NAOJ / KAGRA VIS subgroup R. Takahashi, H. Ishizaki, S. Sato, A. Shoda, T. Sekiguchi, Y. Fujii, T. Miyamoto, T. Ushiba, N. Hirata, K. Hayama, T. Akutsu, Y. Aso, R. Flaminio, R. DeSalvo GWADW 2017, Hamilton Island

Contents KAGRA cryogenic suspension: Type-A SAS Modal damping control of Type-A SAS Cryogenic and underground issues GWADW 2017, Hamilton Island

Seismic Attenuation Systems Type-A Seismic Attenuation Systems in KAGRA Type-B Type-Bp GWADW 2017, Hamilton Island

Type-A SAS Suspension for arm cavity mirrors Tower (room temperature) ETMY ITMY 13.5 m ITMX ETMX Suspension for arm cavity mirrors Tower (room temperature) Cryogenic payload GWADW 2017, Hamilton Island

Type-A SAS Suspension for arm cavity mirrors Tower (room temperature) ETMY ITMY 13.5 m ITMX ETMX Suspension for arm cavity mirrors Tower (room temperature) Cryogenic payload GWADW 2017, Hamilton Island

Features of Type-A SAS Inverted pendulum legs Parallel chain (Ground) Parallel chain Geometric Anti-Spring (GAS) filters Platform Mario-nette MRM IM TM RM IRM Cryogenic payload GWADW 2017, Hamilton Island

Observable DoFs (Tower) LVDT Accelerometer Filter 0 F0 Long., Trans., Yaw GAS relative Vertical F0-F1 F1-F2 F2-F3 F3-BF BF-PF Filter 1 LVDT Filter 2 Filter 3 Bottom Filter (BF) LVDT BF 6DoFs * From ground or mass relative Vertical Yaw Roll Longitudinal Transverse Next page Pitch GWADW 2017, Hamilton Island

Observable DoFs (Payload) Platform Optical lever PF Roll, Pitch, Yaw Optical lever Photo-sensor Marionette - MRM MN Roll, Pitch, Yaw MN-MRM 6DoFs IM - IRM IM-IRM 6DoFs Photo-sensor TM - RM Optical lever TM Pitch, Yaw * From ground or mass relative GWADW 2017, Hamilton Island

Controllable DoFs Coil-magnet actuator (all) Filter 0 Filter 1 F0 Long., Trans., Yaw GAS relative Vertical F0-F1 F1-F2 F2-F3 F3-BF BF-PF Filter 1 Filter 2 Coil-magnet actuator (all) Filter 3 Bottom Filter BF 6DoFs Platform MN-MRM 6DoFs MN - MRM IM-IRM 6DoFs IM - IRM TM - RM TM-RM Long., Pitch, Yaw GWADW 2017, Hamilton Island

F7 LVDT in Adv. Virgo → re-designed for KAGRA BF LVDT F7 LVDT in Adv. Virgo → re-designed for KAGRA GWADW 2017, Hamilton Island

Configuration of BF LVDT Vertical x3 Horizontal x3 GWADW 2017, Hamilton Island

Eigenmodes in Type-A ︙ Totally 75 eigenmodes #1: Y whole chain 0th 0.067Hz 0.067Hz #1: Y whole chain 0th #2: Y whole chain 1st #3: T whole chain 0th 　 IP translation #4: L whole chain 0th 　 IP translation #5: Y whole chain 2nd #6: Y whole chain 3rd ︙ Totally 75 eigenmodes #1 #2 #3 #4 #5 #6 GWADW 2017, Hamilton Island

Horizontal Actuators Sensors Servo IP LVDT (Only tower part) GAS Coil-magnet IP LVDT Horizontal (Only tower part) Coil-magnet GAS Coil-magnet BF LVDT Servo Servo GWADW 2017, Hamilton Island

Open-loop TF (F0 Longitudinal) 1st pendulum 0.454 Hz IP horizontal 0.067 Hz 0th pendulum 0.207 Hz GWADW 2017, Hamilton Island

Open-loop TF (BF Yaw) 0.018 Hz 0.088 Hz 0.120 Hz Whole chain 0th Whole chain 2nd 0.088 Hz Whole chain 3nd 0.120 Hz GWADW 2017, Hamilton Island

Vertical Actuators Sensors Servo IP LVDT GAS LVDT BF LVDT Servo Coil-magnet IP LVDT Vertical Coil-magnet GAS LVDT Coil-magnet BF LVDT Servo Servo GWADW 2017, Hamilton Island

Open-loop TF (GAS F0 Vertical) Whole chain 0th 0.148 Hz … Whole chain 1st 0.413 Hz Whole chain 2nd 0.120 Hz GWADW 2017, Hamilton Island

Decay Time (IP + BF + GAS Damping) Damping Time [sec] Requirement (< 60 sec.) GWADW 2017, Hamilton Island

Next To-do Sensor blending on IP control LVDT displacement sensor + Accelerometer Seismic re-introduction from BF control EQ-stop mechanical eigenmode analysis Sensor/Actuator decoupling Damping strategy in cryogenic payload GWADW 2017, Hamilton Island

Cryogenic and Underground Issues GWADW 2017, Hamilton Island

Impact of Heat Link Seismic noise from HL Platform Mario-nette MRM IM TM RM IRM *Old design!! Seismic noise from HL Heat-link suspension (double pendulum) GWADW 2017, Hamilton Island

Wire Shrinkage ~ 1.5 mm ~ 0.1 mm ✔ Total wire shrinkage for each chain Platform Mario-nette MRM IM TM RM IRM Total wire shrinkage for each chain ~ 1.5 mm Relative shift ~ 0.1 mm ✔ * Rough estimation Maraging CuBe CuBe CuBe Sapphire CuBe GWADW 2017, Hamilton Island

Temperature Gradient Temperature sensor 300 K Bottom Filter Cryostat GWADW 2017, Hamilton Island

Seismic in Underground Microseismic @ 0.2 Hz [1x10-7 ~ 3x10-6 ] m/Hz1/2 GWADW 2017, Hamilton Island A. Shoda, Poster in GWADW 2016

Temperature in Underground PSL Center X-end Y-end A. Shoda, Poster in GWADW 2016 GAS thermal drift ➢ Δz / ΔT = 0.69 mm [mm/K] GWADW 2017, Hamilton Island

Practical Problem on Installation Not accessible Release Sensor (ON/OFF) JGW-D1605452 Dummy Payload GWADW 2017, Hamilton Island

How Is Type-A SAS Now? F1 is sitting on the 2nd floor chamber Klog 2737 F1 is sitting on the 2nd floor chamber GWADW 2017, Hamilton Island

Summary KAGRA Cryogenic suspension: Type-A SAS Under installation Damping control design for tower ✔ Tuning of the control along w/ noise estimation Cryogenic and underground issues Vibration analysis of the heat links Treatment of cooling effects on the suspension Implementation of underground monitors into control GWADW 2017, Hamilton Island

Backup Slides GWADW 2017, Hamilton Island

Stage Configuration Coordinate difinition Vertical Yaw Roll 13.5 m F3 Yaw Roll BF Longitudinal Transverse Pitch PF Cryogenic Payload MT MRM IM IRM TM RM GWADW 2017, Hamilton Island

Bottom Filter LVDT Sensor / Actuator (suspended stage) Sensor / Actuator Primary coil 10 kHz modul. Displacement sensor of the primary coil Local Oscillator Secondary coils Displacement signal (Ground-side) Mixer Low-pass GWADW 2017, Hamilton Island

Bottom Filter LVDT Sensor / Actuator Coil-magnet actuator (suspended stage) Sensor / Actuator Magnet Coil-magnet actuator Driving-frequency separation Sensor: 10 kHz (high) Actuator: < 10 Hz (Low) Secondary coils Coil Driver Actuation signal (Ground-side) GWADW 2017, Hamilton Island

Yend X Test Schedule end Apr. May Jun. Jul. Aug. Sep. Oct. Installation Test w/ DP In air, Room temp 5/16 – 6/11 Full hanging test & Cooling w/ sapphire dummy 6/12 – 9/14 VIS Installation Test w/ DP In vaccum, Room temp 8/1 – 10/15 GWADW 2017, Hamilton Island

KAGRA EYV Room

Vertical Chamber Opened

Future update System identification test Real-system modeling Implementation of Kalman filter Estimation of system parameters Feedback design optimization with machine learning LQ regulator + Machine learning → weight optimization Feedforward control with underground environmental monitors GWADW 2017, Hamilton Island