1 / 22

Vibration Isolation Group

This presentation discusses the Vibration Isolation Group's work on payload design, prototype testing, and system modeling. The group includes researchers from various institutions and focuses on improving the vibration isolation system for the LCGT project. The presentation covers topics such as the configuration types, sensor and actuator technologies, point mass and rigid body modeling, and simulations using software tools like SimMechanics and Octopus.

schechter
Download Presentation

Vibration Isolation Group

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vibration Isolation Group R. Takahashi (ICRR) Chief T. Uchiyama (ICRR) Payload design H. Ishizaki (NAOJ) Prototype test R. DeSalvo (Caltech) SAS design A. Takamori (ERI) SAS design E. Majorana (INFN)* Payload modeling T. Sekiguchi (ICRR) System modeling LCGT A-review of VIS (29 Nov., 2010) * unofficial member

  2. R&D Payload and GASF prototype in NAOJ 2011 TAMA-SAS in TAMA 2005-2009 One-leg IP in Kamioka 2009-2010

  3. Disposition of vibration isolation system

  4. Vacuum chamber A) φ2m × (2.5m + 2.45m cryostat) B) φ2m × 4.3m C) φ2m × 3m Vibration Isolation System A) IP + GASF (3→4 stage) + Payload (cryogenic) B) IP + GASF (2 stage) + Payload (room temp.) C) STACK + Double-pendulum Configuration

  5. Configuration

  6. Type-A (old) Support structure of SAS tower is too weak.

  7. Type-B

  8. Type-C

  9. Sensor and actuator ACC: accelerometer, LVDT: linear variable differential transformer PS: position sensor, OL: optical lever, MC: magnet-coil, STEP: stepping motor, PICO: picomotor For cryogenic Stepping motor: tested in Rome, 4.8K ok! Position sensor: shadow sensor → fiber sensor Actuator: design taking account of eddy current problem

  10. Point Mass Modelby R. Takahashi Type-A (old) • Equation of motion of 8 material points model • 8ｘ8 stiffness matrix • Refer parameters of TAMA-SAS • Calculated by MATLAB

  11. Type-A (new) • Equation of motion of 9 material points model • 10ｘ10 stiffness matrix • 2-layer structure • Calculated by MATLAB Filter3 + CB

  12. Type-B • Equation of motion of 7 material points model • 7ｘ7 stiffness matrix • 10kg LIGO mirror • Calculated by MATLAB

  13. Type-C • Equation of motion of 6 material points model • 6ｘ6 stiffness matrix • Model for Stack is simplified • Calculated by MATLAB

  14. Displacement of test mass • The horizontal isolation >3Hz is due to a heat link of 0.03Hz. • The vertical isolation is better than the horizontal isolation around 1Hz because of 4 stage GAS filters. • Since the final stage (TM) is suspended by 4 sapphire fibers of φ1.8mm, the vertical resonant frequency is about 100Hz. • Heat links of 0.03Hz with 1% coupling from vertical mode satisfy demands at 10Hz.

  15. Displacement of each system • The isolation of Type-B is better than the isolation of Type-A with heat links >4Hz. • When the part of IP-GASF of Type-B is fixed (iLCGT), the isolation of Type-A is worse than the isolation of Type-C with stack >20Hz.

  16. RMS Integration 0.01-4Hz (Integration 0.1-4Hz) Type-A,B vs. C 0.1 → 2 [mm] x20 0.1 → 2 [mm/s] x20

  17. Rigid Body Modelby T. Sekiguchi SimMechanics (The MathWorksTM) Based on multi body dynamics • If geometric/topological parameters are determined, equations of motion/transfer functions are obtained almost automatically. • Direct integration into the Simulink environment. • How it is calculated is in a black box.

  18. Test Simulation (2D SUS) The parameters (mass, wire length, etc) may be changed easily. Geometric asymmetry may be taken into account. (Now Constructing) Triple pendulum suspension system with y, yaw and roll suppressed. Calculated transfer functions (X-X, X-Pitch, X-Z) without geometric asymmetry

  19. Rigid Body Modelby E. Majorana Octopus Octopus is a non-official Virgo tool. The modeling will be used for AdV, but it is not the only model that can be used. It provides (once completed): I) Point-by-point 6x6 matrixes of Force/displacement TFs or displacement ratios. II) Designing tool: several configurations or parameter tuning, within a given configuration can be explored. III) Some add-ons as fitting a dataset of experimental TF and extracting a fit which can be used to extract actual mechanical parameters (…).

  20. Example of outputs of Octopus X Y Z Tx Ty Tz Fx Fy Fz Ftx Fty Ftz This presentation/practical cases. - Often it is useful to show longitudinal/pitch and transversal/yaw sub-matrixes - In the case of LCGT, the Vertical might be more crucial and should be included.

  21. Schedule

  22. Procedure of installation for ITM/ETM • Set IP/GASF （Tower） • Connection of Dummy mass (200kg+100kg) • Embed accelerometers (geophones) • Wiring • Release Tower • Control test(diagonization) 2 month for 2 sets • Fix Tower • Dismount Dummy mass (100kg) • Connection of Payload • Wiring • Release Payload • Control test 1 month for 2 sets • Release Tower / Fix Dummy mass (200kg)

More Related