Current Work on Hydraulics for LIGO 1 and Advanced LIGO

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Current Work on Hydraulics for LIGO 1 and
Advanced LIGO
JILA, LLO, LSU, MIT, Stanford
Rich Abbott, Graham Allen, Daniel DeBra, Joe
Giaime, Giles Hammond, Marcel Hammond, Corwin
Hardham, Jonathan How, Wensheng Hua, Brian Lantz,
Ken Mason, Rich Mittleman, Jamie Nichol, Joshua
Phinney, Gerry Stapfer
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Functional Description of the System
10-7 m rms (0.1Hz), 10-8 m rms (1Hz), 4
10-10 m/vHz
10-7 m rms (0.1Hz), 10-11 m rms (1Hz), 2
10-13 m/vHz (10 Hz)
10-14 m rms differential, 10-19 m/vHz (10 Hz)
10-6 m rms above 0.1Hz 10-8 m rms above 1Hz,
4 10-10 m/vHz at 10 Hz
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View of the LIGO vacuum tanks
BSC
HAM
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Motivation for an External Stage

• Isolation
• From the micro-seismic peak to 10 Hz
• Alignment
• Seasonal Temperature Changes
• Control Reallocation
• Reduce control effort / noise from inner stages
• High Impedance Support
• Inner stages react against stiff, damped
  foundation

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Performance Requirements

• Range of Motion
• Mechanical Adjustment 5 mm.
• Active Control /- 1 mm.
• Response
• Initial Response 1 mm. in 10 sec.
• Bandwidth .1 - 10 Hz.
• Resolution and Noise
• Reduce the ground motion by 10 from 0.1 to 3 Hz

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Differential Bellows for Quiet Actuator

• 1) Pump
• 2) Differential Flapper Valve
• 3) Bellows Supply
• 4) Differential Bellows
• 5) Actuation Plate

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The Quiet Hydraulic Actuator
Displacement Sensor
Bellows
Servo Valve
Actuation Plate
Current Design Implemented On LIGO Pier
Current Design
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Conditioning a Pressure Source
Active and Passive Suppression of Pressure
Fluctuations
Accumulator
Compensator
Pressure Sensor
Pump
Servo Valve
Reservoir
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Pressure Noise at the Actuator
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The Test Platform at Stanford
Vertical Actuator
Displacement Sensor
Seismometer (Geotech S-13)
Seismometer (Streckeisen STS-2)
800 lb Test Mass
Vertical Actuator
Horizontal Actuator
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Sensor Correction
Compensator
zm - zg


zg
External Alignment Input
STS2 Filter
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Vertical Isolation
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Horizontal Isolation
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New Pumping Stand

• Build new system withimproved low freq range,
  and capacity to drive 8 actuators.
• Allow Stanford and LASTI to order identical
  stations (easier debugging).

Reservoir
Motor and pump
Granite block(isolation)
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New Pump Station is Progressing
Motor controller
Filter
Accumulator
Pressure sensor
Motor
Bypass valve
Pump
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Candidate Actuators
Mechanical Noise
Displacement
Hysteresis
Stiffness
Stiction
Velocity
Force

• Hydraulic

High
Med
Low
Med
Low
Low
Low
Ball Screw
High
High
Low
High
High
High
Low
Linear Motor
High
High
High
Low
Low
Low
Low
Piezo orMagnetostriction
Low
High
High
Low
Low
High
High
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Equations of Motion
Mass
Volumes
Flow
Valve