Non-sensitive axis feedback control of test mass in full-maglev vertical superconducting gravity instruments

TL;DR

This paper presents a novel non-sensitive axis feedback control method for a superconducting gravity instrument, effectively reducing test mass displacement and noise in the sensitive axis through specialized superconducting circuits and PID control.

Contribution

It introduces a new feedback control approach that decouples and detects multi-degree-of-freedom motions of the test mass in a superconducting gravity instrument.

Findings

Test mass displacement reduced by about one order of magnitude.

Noise level in the sensitive axis decreased.

Successful control of test mass in laboratory conditions.

Abstract

Non-sensitive axis feedback control is crucial for cross-coupling noise suppression in the application of full-maglev vertical superconducting gravity instruments. This paper introduces the non-sensitive axis feedback control of the test mass in a home-made full-maglev vertical superconducting accelerometer. In the feedback system, special superconducting circuits are designed to decouple and detect the multi-degrees-of-freedom motions of the test mass. Then the decoupled motion signals are dealt with by the PID controller and fed back to the side-wall coils to control the test mass. In our test, the test mass is controlled successfully and the displacement is reduced by about one order of magnitude in the laboratory. Accordingly, the noise level of the vertical superconducting accelerometer in the sensitive axis is also reduced.