Device for Evaluating the Performance of High-Precision Accelerometers as Motion Sensors for an Active Vibration Isolation System

The high-precision electrostatic accelerometer is the key payload for satellite gravity measurement, so ground testing and verification of its performance is critical. Our group has previously developed a series of test benches that can be used to provide a ground test environment of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-9}$ </tex-math></inline-formula> m/s2/Hz<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> level. In this article, a novel performance evaluation device for high-precision accelerometers based on an active vibration isolation system (AVIS) is proposed. An electrostatic accelerometer with a theoretical noise level of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{-10}$ </tex-math></inline-formula> m/s2/Hz<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> is used as the motion sensor, and the active feedback control is carried out in combination with the four-wire pendulum. The system noise model is further analyzed in detail. The experimental results show that the vibration transmissibility of this system using acceleration sensing is better than that using velocity sensing, which verifies the effectiveness of the proposed method. The total residual noise level on the test bench measured by the seismometer is verified to be about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 10^{-9}$ </tex-math></inline-formula> m/s2/Hz<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> from 0.5 to 0.8 Hz, while the performance of the electrostatic accelerometer itself is evaluated to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$7\times 10^{-10}$ </tex-math></inline-formula> m/s2/Hz<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{1/2}$ </tex-math></inline-formula> from 0.3 to 0.6 Hz.