An inverted pendulum preisolator stage for the VIRGO suspension system

Losurdo, G.; Bernardini, M. G.; Braccini, S.; Bradaschia, C.; Casciano, C.; Dattilo, V.; Salvo, R. De; Virgilio, A. Di; Frasconi, F.; Gaddi, A.; Gennai, A.; Giazotto, A.; Pan, H.; Paoletti, F.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Taddei, R.; Zhang, Z.; Cella, G.; Cuoco, E.; D’Ambrosio, E.; Fidecaro, F.; Gaggero, Stefano; Penna, P. La; Mancini, Stefano; Poggiani, R.; Viceré, A.; Mazzoni, M.; Stanga, R.; Holloway, L.; Winterflood, John

doi:10.1063/1.1149783

Cited by 83 publications

(32 citation statements)

References 13 publications

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“…In this frequency range, the seismic noise limits the detector sensitivity. One of the most efficient Seismic Attenuation System (SAS) for gravitational waves interferometers is a chain of pendula suspended from a very low-frequency stage called Inverted Pendulum [6]. Each optical component of the interferometer is supported by means of this particular suspension system.…”

Section: The Seismic Attenuation Systemmentioning

confidence: 99%

Model independent numerical procedure for the diagonalization of a Multiple Input Multiple Output dynamic system

Persichetti

Chiummo

Acernese

et al. 2010

2010 17th IEEE-NPSS Real Time Conference

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Seismic noise limits Earth based gravitational wave interferometric detectors at low frequencies. The detection threshold can be lowered down to a few Hz using a seismic attenuation system based on Inverted Pendulum (IP) which sustains interferometer optical components by means of a pendula chain. The IP, acting as a mechanical low pass filter, is able to filter out seismic noise and at the same time it provides a quasi-inertial stage where the suspension point of the pendula chain lies. The IP is a three degrees of freedom system, it has two translational and one rotational modes. Therefore, to fully determinate its position, three independent sensors are mounted at the periphery of the IP top table. For the same reason, three independent actuators are used to move the IP. The geometrical position of the sensors is different from actuator positions, in addition, both of them are not connected to the normal modes of the IP. Each sensor will be sensitive in all the three IP normal modes and each actuator will generate movements which are a mix of the three modes. To take advantage of controlling a SISO (Single Input Single Output) system instead of a MIMO (Multiple Input Multiple Output) system, a diagonalization of the actuation and detection system is needed. An original and model independent experimental procedure for determining the system dynamic, giving an effective diagonalization has been developed and tested.

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Section: The Seismic Attenuation Systemmentioning

confidence: 99%

Model independent numerical procedure for the diagonalization of a Multiple Input Multiple Output dynamic system

Persichetti

Chiummo

Acernese

et al. 2010

2010 17th IEEE-NPSS Real Time Conference

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show abstract

“…To simplify the control strategy the sensors outputs and the actuators currents are digitally recombined to obtain independent SISO (single in-single out) systems (fig. 2): the system is described in the normal modes coordinates (for a description of the diagonalization procedure see [5,6]). Each normal mode is associated to a so called virtual sensor (sensitive to that mode and "blind" to the others) and to a virtual actuator (acting on one mode only, leaving the others undisturbed).…”

Section: The Control Strategymentioning

confidence: 99%

Inertial control of the VIRGO superattenuator

Losurdo¹,

Groups²

2000

AIP Conference Proceedings

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Abstract. The VIRGO superattenuator (SA) is effective in depressing the seismic noise below the thermal noise level above 4 Hz. On the other hand, the residual mirror motion associated to the SA normal modes can saturate the dynamics of the interferometer locking system. This motion is reduced implementing a wideband (DC-5 Hz) multidimensional control (the so called inertial damping) which makes use of both accelerometers and position sensors and of a DSP system. Feedback forces are exerted by coil-magnet actuators on the top of the inverted pendulum. The inertial damping is successful in reducing the mirror motion within the requirements. The results are presented. I INTRODUCTIONThe test mass suspension of the VIRGO detector, the superattenuator (SA) [1], has been designed in order to suppress the seismic noise below the thermal noise level above 4 Hz. The expected residual motion of the mirror is ∼ 10 −18 m √ Hz @4 Hz. At lower frequencies, the residual motion of the mirror is much larger (∼ 0.1 mm RMS), due to the normal modes of the SA (the resonant frequencies of the system are in the range 0.04-2 Hz).To lock the VIRGO interferometer the RMS motion of the suspended mirrors must not exceed 10 −12 m (to avoid the saturation of the read-out electronics). VIRGO locking strategy is based on a hierarchical control: feedback forces can be exerted on 3 points of the SA (inverted pendulum (IP) [2], marionetta and mirror). The control on the 3 points is operated in different ranges of frequency and amplitude. The maximum mirror displacement that can be controlled from the marionetta without injecting noise in the detection band is ∼ 10 µm. Therefore, a damping of the SA normal modes is required for a correct operation of the locking system. An active control of the SA normal modes, using sensors and actuators on 1)

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“…A different approach in terms of pre-isolation has been taken by other groups adopting a 'soft' design [32][33][34]. Primarily based on very low resonant frequencies, these are achieved with different damping solutions based on anti-spring designs and electromagnetic coupling, complemented with low bandwidth feedback control loops.…”

Section: Vibration Isolationmentioning

confidence: 99%

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors

Barriga¹,

Blair²,

Coward³

et al. 2010

Class. Quantum Grav.

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This paper describes the proposed AIGO detector for the worldwide array of interferometric gravitational wave detectors. The first part of the paper summarizes the benefits that AIGO provides to the worldwide array of detectors. The second part gives a technical description of the detector, which will follow closely the Advanced LIGO design. Possible technical variations in the design are discussed.

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An inverted pendulum preisolator stage for the VIRGO suspension system

Cited by 83 publications

References 13 publications

Model independent numerical procedure for the diagonalization of a Multiple Input Multiple Output dynamic system

Model independent numerical procedure for the diagonalization of a Multiple Input Multiple Output dynamic system

Inertial control of the VIRGO superattenuator

AIGO: a southern hemisphere detector for the worldwide array of ground-based interferometric gravitational wave detectors

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