26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Advanced Controls for the TorPeDO's Seismic Isolation Chain

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral AIP | General Relativity and Gravitation (ASGRG) Afternoon Tea and Poster Session 2

Speaker

Lane Scheel (Australian National University)

Description

The Torsion Pendulum Dual Oscillator (TorPeDO) experiment [1] aims to directly detect Newtonian noise, a fundamental limit to the low-frequency sensitivity of future terrestrial gravitational-wave detectors. TorPeDO employs a four-stage seismic isolation chain comprising an inverted pendulum, a vertical geometric anti-spring (GAS) filter, an intermediate mass, and a penultimate mass from which the transducer is suspended [2]. Achieving thermal-noise-limited sensitivity requires many orders of magnitude of seismic isolation. Active control of the soft plant dynamics supresses ground motion across the 10mHz-10Hz frequency band of interest.

Moving beyond single-input single-output (SISO) servo controllers, we present a multi-input multi-output (MIMO) state-space controller which simultaneously utilizes all sensors and actuators on the inverted pendulum. This controller is synthesized with the intent of minimizing the transfer of ground motion into the differential yaw of the TorPeDO transducer. We also present the latest status of an expanded controller incorporating sensors and actuators on every stage of the suspension chain.

[1] Chua et al, Appl. Phys. Lett. 122, 201102 (2023)
[2] P.W.F. Forsyth, PhD Thesis, ANU (2022)