Control of the KAGRA Cryogenic Vibration Isolation System

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. De. Salvo GWADW 2017, Hamilton Island 1

Contents p KAGRA cryogenic suspension: Type-A SAS p Modal damping control of Type-A SAS p Cryogenic and underground issues GWADW 2017, Hamilton Island 2

Type-A Seismic Attenuation Systems in KAGRA Type-Bp GWADW 2017, Hamilton Island 3

Type-A SAS ETMY ITMY 13. 5 m ITMX ETMX Suspension for arm cavity mirrors • Tower (room temperature) • Cryogenic payload GWADW 2017, Hamilton Island 4

Type-A SAS ETMY ITMY 13. 5 m ITMX ETMX Suspension for arm cavity mirrors • Tower (room temperature) • Cryogenic payload GWADW 2017, Hamilton Island 5

Features of Type-A SAS Inverted pendulum legs (Ground) Parallel chain Platform Marionette MRM IM IRM Geometric Anti-Spring (GAS) filters Cryogenic payload TM RM GWADW 2017, Hamilton Island 6

Observable Do. Fs (Tower) Filter 0 Filter 1 Filter 2 Filter 3 Bottom Filter • • • F 0 Long. , Trans. , Yaw • LVDT • Accelerometer GAS relative Vertical F 0 -F 1 F 1 -F 2 F 2 -F 3 F 3 -BF BF-PF • LVDT • (BF) LVDT BF 6 Do. Fs * From ground or mass relative Vertical Yaw Roll GWADW 2017, Hamilton Island Ø Next page Longitudinal Pitch Transverse 7

Observable Do. Fs (Payload) Platform Marionette - MRM IM - IRM TM - RM PF Roll, Pitch, Yaw • Optical lever MN Roll, Pitch, Yaw MN-MRM 6 Do. Fs • Optical lever • Photo-sensor IM-IRM 6 Do. Fs • Photo-sensor TM Pitch, Yaw • Optical lever * From ground or mass relative GWADW 2017, Hamilton Island 8

Controllable Do. Fs Filter 0 Filter 1 Filter 2 Filter 3 Bottom Filter Platform MN - MRM IM - IRM TM - RM GWADW 2017, Hamilton Island F 0 Long. , Trans. , Yaw • • • GAS relative Vertical F 0 -F 1 F 1 -F 2 F 2 -F 3 F 3 -BF BF-PF Coil-magnet actuator (all) BF 6 Do. Fs MN-MRM 6 Do. Fs IM-IRM 6 Do. Fs TM-RM Long. , Pitch, Yaw 9

BF LVDT F 7 LVDT in Adv. Virgo → re-designed for KAGRA GWADW 2017, Hamilton Island 10

Configuration of BF LVDT Vertical x 3 GWADW 2017, Hamilton Island Horizontal x 3 11

Eigenmodes in Type-A 0. 067 Hz #1: Y whole chain 0 th #2: Y whole chain 1 st #3: T whole chain 0 th 　 IP translation #4: L whole chain 0 th 　 IP translation #5: Y whole chain 2 nd #6: Y whole chain 3 rd � #1 #2 GWADW 2017, Hamilton Island #3 #4 #5 #6 � Totally 75 eigenmodes 12

Actuators Sensors Coil-magnet IP LVDT Horizontal (Only tower part) Coil-magnet GAS Coil-magnet BF LVDT Servo GWADW 2017, Hamilton Island 13

Open-loop TF (F 0 Longitudinal) 1 st pendulum 0. 454 Hz IP horizontal 0. 067 Hz 0 th pendulum 0. 207 Hz GWADW 2017, Hamilton Island 14

Open-loop TF (BF Yaw) Whole chain 0 th 0. 018 Hz GWADW 2017, Hamilton Island Whole chain 2 nd 0. 088 Hz Whole chain 3 nd 0. 120 Hz 15

Actuators Sensors Coil-magnet IP LVDT Vertical Coil-magnet GAS LVDT Coil-magnet BF LVDT Servo GWADW 2017, Hamilton Island 16

Open-loop TF (GAS F 0 Vertical) Whole chain 0 th 0. 148 Hz GWADW 2017, Hamilton Island Whole chain 1 st 0. 413 Hz Whole chain 2 nd 0. 120 Hz … 17

Damping Time [sec] Decay Time (IP + BF + GAS Damping) GWADW 2017, Hamilton Island Requirement (< 60 sec. ) 18

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 19

Cryogenic and Underground Issues GWADW 2017, Hamilton Island 20

Impact of Heat Link Platform Marionette MRM *Old design!! IM IRM Seismic noise from HL TM RM GWADW 2017, Hamilton Island Ø Heat-link suspension (double pendulum) 21

Wire Shrinkage Platform Maraging Marionette Cu. Be IM Sapphire TM GWADW 2017, Hamilton Island • Total wire shrinkage for each chain Cu. Be MRM Cu. Be IRM Cu. Be ~ 1. 5 mm • Relative shift ~ 0. 1 mm ✔ * Rough estimation RM 22

Temperature Gradient 300 K Bottom Filter Temperature sensor Cryostat GWADW 2017, Hamilton Island 23

Seismic in Underground Microseismic @ 0. 2 Hz [1 x 10 -7 ~ 3 x 10 -6 ] m/Hz 1/2 GWADW 2017, Hamilton Island A. Shoda, Poster in GWADW 2016 24

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 25

Practical Problem on Installation Release Sensor (ON/OFF) Not accessible Dummy Payload GWADW 2017, Hamilton Island JGW-D 1605452 26

How Is Type-A SAS Now? Klog 2737 Ø F 1 is sitting on the 2 nd floor chamber GWADW 2017, Hamilton Island 27

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 28

Backup Slides GWADW 2017, Hamilton Island 29

Stage Configuration F 0 F 1 ØCoordinate difinition 13. 5 m F 2 Vertical F 3 BF Yaw Roll Longitudinal PF MT MRM IM IRM TM RM GWADW 2017, Hamilton Island Cryogenic Payload Pitch Transverse 30

Bottom Filter LVDT Bottom Filter (suspended stage) Sensor / Actuator 10 Primary coil zm k. H l. u od • Displacement sensor of the primary coil Local Oscillator Secondary coils Displacement signal (Ground-side) Mixer GWADW 2017, Hamilton Island Low-pass 31

Bottom Filter LVDT Bottom Filter (suspended stage) Sensor / Actuator Magnet • Coil-magnet actuator • Driving-frequency separation – Sensor: 10 k. Hz (high) – Actuator: < 10 Hz (Low) Secondary coils Coil Driver (Ground-side) GWADW 2017, Hamilton Island Actuation signal 32

Test Schedule Apr. May Installation Y end Test w/ DP In air, Room temp 5/16 – 6/11 VIS Installation X Jun. Jul. Aug. Sep. Oct. Full hanging test & Cooling w/ sapphire dummy 6/12 – 9/14 Test w/ DP In vaccum, Room temp 8/1 – 10/15 end GWADW 2017, Hamilton Island 33

KAGRA EYV Room 34

Vertical Chamber Opened 35

Future update • System identification test Ø Real-system modeling • Implementation of Kalman filter Ø Estimation of system parameters • Feedback design optimization with machine learning Ø LQ regulator + Machine learning → weight optimization • Feedforward control with underground environmental monitors GWADW 2017, Hamilton Island 36