Particle swarming of sensor correction filters
Reducing the impact of seismic activity on the motion of suspended optics is essential for the operation of ground-based gravitational wave detectors. During periods of increased seismic activity, low-frequency ground translation and tilt cause the Advanced LIGO observatories to lose 'lock', reducing their duty cycles. This paper applies modern global-optimisation algorithms to aid in the design of the 'sensor correction' filter, used in the control of the active platforms. It is shown that a particle swarm algorithm that minimises a cost-function approximating the differential root mean squared velocity between platforms can produce control filters that perform better across most frequencies in the control bandwidth than those currently installed. These tests were conducted using training data from the LIGO Hanford Observatory seismic instruments and simulations of the Horizontal Access Module Internal Seismic Isolation platforms. These results show that new methods of producing control filters are ready for use at LIGO. The filters were implemented at LIGO's Hanford Observatory, and use the resulting data to refine the cost function.
© 2020 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 30 June 2020. Revised 7 August 2020. Accepted 27 August 2020. Published 21 September 2020. We would like to thank Brett Shapiro and Brian Lantz for their many useful suggestions and comments. Furthermore, discussions with Will Farr gave an insightful approach to building filters.
Submitted - 2006.15080.pdf
Published - Carter_2020_Class._Quantum_Grav._37_205009.pdf