Design and validation of a high-voltage levitation circuit for electrostatic accelerometers

High-precision electrostatic accelerometers have achieved remarkable success in satellite Earth gravity field recovery missions. Ultralow-noise inertial sensors play important roles in space gravitational wave detection missions such as the Laser Interferometer Space Antenna (LISA) mission, and key technologies have been verified in the LISA Pathfinder mission. Meanwhile, at Huazhong University of Science and Technology (HUST, China), a space accelerometer and inertial sensor based on capacitive sensors and the electrostatic control technique have also been studied and developed independently for more than 16 years. In this paper, we review the operational principle, application, and requirements of the electrostatic accelerometer and inertial sensor in different space missions. The development and progress of a space electrostatic accelerometer at HUST, including ground investigation and space verification are presented.

Section: Progress Of Electrostatic Accelerometer Development At Humentioning

confidence: 99%

Research and Development of Electrostatic Accelerometers for Space Science Missions at HUST

Bai

et al. 2017

“…It is clear that the noise floor has imposed heavy limitation on the MESA performance for this sensor use a 3C geophone. The measured noise of the MESA is mainly composed of thermo-mechanical noise, the position sensing noise, the digital controller noise, and the seismic noise in an Earth-bound test environment [ 23 ]. The thermo-mechanical noise (or Brownian noise) derives from the fact that the MEMS accelerometer consist of an electrostatically-suspended PM which is susceptible to the mechanical noise that results from molecular agitation.…”

Section: Experimental Performance Of the Mesamentioning

confidence: 99%

Self-Locking Avoidance and Stiffness Compensation of a Three-Axis Micromachined Electrostatically Suspended Accelerometer

Yin

Sun

Han

2016

A micromachined electrostatically-suspended accelerometer (MESA) is a kind of three-axis inertial sensor based on fully-contactless electrostatic suspension of the proof mass (PM). It has the potential to offer broad bandwidth, high sensitivity, wide dynamic range and, thus, would be perfectly suited for land seismic acquisition. Previous experiments showed that it is hard to lift up the PM successfully during initial levitation as the mass needs to be levitated simultaneously in all six degrees of freedom (DoFs). By analyzing the coupling electrostatic forces and torques between three lateral axes, it is found there exists a self-locking zone due to the cross-axis coupling effect. To minimize the cross-axis coupling and solve the initial levitation problem, this paper proposes an effective control scheme by delaying the operation of one lateral actuator. The experimental result demonstrates that the PM can be levitated up with six-DoF suspension operation at any initial position. We also propose a feed-forward compensation approach to minimize the negative stiffness effect inherent in electrostatic suspension. The experiment results demonstrate that a more broadband linear amplitude-frequency response and higher suspension stiffness can be achieved, which is crucial to maintain high vector fidelity for potential use as a three-component MEMS geophone. The preliminary performance tests of the three-axis linear accelerometer were conducted under normal atmospheric pressure and room temperature. The main results and noise analysis are presented. It is shown that vacuum packaging of the MEMS sensor is essential to extend the bandwidth and lower the noise floor, especially for low-noise seismic data acquisition.

“…This prototype has similar dimensions to the inner cylindrical accelerometer of the differential NEP instrument. However, very high voltage needs to be generated in order to counteract the 1 g Earth’s gravity along the y / z axes [ 28 ]. To lower the required suspension voltage, the injection electrode is moved from the inner cylinder to the outer one so as to provide larger radial suspension electrode areas.…”

Section: Development Status Of a Nep Instrument Prototypementioning

confidence: 99%

“…Evaluating the performance of electrostatic accelerometers on the ground is inevitably limited by Earth’s 1 g gravity. To meet the needs of the electrostatic levitation, a high voltage amplifier-based suspension scheme is suitable to test the engineering and flight models of accelerometers for space missions, even though the resolution of the accelerometers could not be directly verified at the designed level due to the seismic noise and the high-voltage coupling limits [ 28 ]. Figure 13 a illustrates the block diagram of the accelerometer electronics mainly consist of six capacitive position sensors, 16 high-voltage amplifiers and a 32-bit control-optimized digital signal processor (DSP), as well as the necessary ADCs and DACs.…”

Section: Development Status Of a Nep Instrument Prototypementioning

confidence: 99%

Design and Fabrication of a Differential Electrostatic Accelerometer for Space-Station Testing of the Equivalence Principle

Han

Liu

et al. 2016

The differential electrostatic space accelerometer is an equivalence principle (EP) experiment instrument proposed to operate onboard China’s space station in the 2020s. It is designed to compare the spin-spin interaction between two rotating extended bodies and the Earth to a precision of 10−12, which is five orders of magnitude better than terrestrial experiment results to date. To achieve the targeted test accuracy, the sensitive space accelerometer will use the very soft space environment provided by a quasi-drag-free floating capsule and long-time observation of the free-fall mass motion for integration of the measurements over 20 orbits. In this work, we describe the design and capability of the differential accelerometer to test weak space acceleration. Modeling and simulation results of the electrostatic suspension and electrostatic motor are presented based on attainable space microgravity condition. Noise evaluation shows that the electrostatic actuation and residual non-gravitational acceleration are two major noise sources. The evaluated differential acceleration noise is 1.01 × 10−9 m/s2/Hz1/2 at the NEP signal frequency of 0.182 mHz, by neglecting small acceleration disturbances. The preliminary work on development of the first instrument prototype is introduced for on-ground technological assessments. This development has already confirmed several crucial fabrication processes and measurement techniques and it will open the way to the construction of the final differential space accelerometer.