Development and experimental investigation of a high-precision capacitive displacement transducer of the inertial sensor for TianQin

Wang, Chengrui; Bai, Yanzheng; Hu, Ming; Li, Duo; Li, Ke; Ouyang, Chaoli; Qu, Shaobo; Xiao, Chunyu; Yang, Xiaotian; Zhou, Annan; Zhou, Zebing

doi:10.1088/1361-6382/acf8a8

Cited by 6 publications

(3 citation statements)

References 23 publications

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“…After the phase alignment system computes the V X and V Y components of the demodulation output, the phase difference can be computed according to Equation (13). The main method to implement arctan computation on FPGA is the CORDIC algorithm.…”

Section: Cordic Modulementioning

confidence: 99%

“…Synchronous demodulators can be categorized into two types based on their circuit structure. The first type is the analog structure [11,12], as detailed in references [6,7,13], which employs a switched structure to achieve the demodulation function. This structure can achieve a reduction in 1/ f noise, thereby enhancing the performance of capacitive sensors.…”

Section: Introductionmentioning

confidence: 99%

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Research and Implementation of a Demodulation Switch Signal Phase Alignment System in Dynamic Environments

Xue,

Yu,

Sui

et al. 2023

Sensors

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In the space gravitational wave detection mission, inertial sensors play the role of providing an inertial reference for the laser interferometric measurement system. Among them, the capacitance sensor serves as the core key technology of the inertial sensor, used to measure the relative position of the test mass (TM) in the electrode cage. The capacitance sensor utilizes synchronous demodulation technology to extract signals from the AC induction signal. When the phase of the demodulation switch signal is aligned, the synchronous demodulator can most effectively filter out noise, thus directly influencing the performance of the capacitance sensor. However, since the TM is in a suspended state, the information read by the capacitance sensor is dynamic, which increases the difficulty of demodulation phase alignment. In light of this, a method is proposed for achieving the phase alignment of the demodulation switch signal in a dynamic environment. This is accomplished by adjusting the phase of the demodulation switch signal, and subsequently computing the phase difference between the AC induction signal and the demodulation switch signal. At the same time, a measurement and evaluation method for phase deviation is also proposed. Ultimately, an automatic phase alignment system for the demodulation switch signal in dynamic environments is successfully implemented on an FPGA platform, and tests are conducted on a hexapod PI console platform to simulate dynamic environments. The experimental results demonstrate that the system accurately achieves phase alignment in the static environment, with a phase deviation of 0.1394 rad. In the simulated dynamic environment, the phase deviation is 0.1395 rad.

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Section: Cordic Modulementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Research and Implementation of a Demodulation Switch Signal Phase Alignment System in Dynamic Environments

Xue,

Yu,

Sui

et al. 2023

Sensors

View full text Add to dashboard Cite

show abstract

“…He proposed a method for achieving phase alignment [ 16 ]. Chengrui Wang implemented a capacitive sensing scheme based on a transformer bridge and synchronous demodulation, enhancing the functionality of the phase-locked loop (PLL) amplifier circuit and reducing the low-frequency 1/f noise [ 17 ]. Ke Li conducted an analysis on the differential capacitive displacement sensor, focusing on how the stability of the carrier signal and the phase difference and fluctuations between the demodulation signals can restrict the modulation–demodulation process and reduce capacitive sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Research on High-Precision Resonant Capacitance Bridge Based on Multiple Transformers

Liu,

Chen,

Wang

et al. 2024

Sensors

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The Taiji program is dedicated to the detection of middle and low-frequency gravitational waves, targeting the 0.1 mHz to 1 Hz frequency band. The project requires an acceleration residual sensitivity of 3 × 10−15 ms−2/Hz1/2, which necessitates a capacitance sensing resolution of 1 aF/Hz1/2 for the capacitive sensing system within the specified frequency range. The noise level of the resonant bridge significantly influences the resolution. Addressing the challenges in enhancing transformer performance parameters in existing resonant capacitance bridges and the constraints on improving the characteristics of resonant capacitance bridges, this study introduces a novel approach to reduce bridge thermal noise without optimizing existing parameters. The simulation results demonstrate that this scheme can reduce the noise to 0.7 times the original level and further reduce bridge thermal noise when other parameters affecting noise are optimized. This not only mitigates the demands for other performance parameters but also increases the range of maximum acceptable resonant frequency deviations and reduces its sensitivity to such variations. Experimental validation confirms that the proposed scheme effectively reduces noise by 0.7 times and improves the resolution of capacitance sensing to 0.6 aF/Hz1/2, thereby advancing the Taiji program gravitational wave detection capabilities.

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Amplitude stability research and experimental investigation of the actuation circuit of the inertial sensor for space gravitational wave detection

Zhang,

Yu,

Lin

et al. 2024

Class. Quantum Grav.

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The primary measure of scientific performance for inertial sensors used in space gravitational wave detection is the residual acceleration noise of the test mass (TM). This residual noise arises from both the internal circuit and the external environment. The actuation circuit, a crucial component of the internal circuit, significantly affects the TM’s residual acceleration noise through its amplitude stability, thereby impacting the scientific performance of the inertial sensor. In this study, we designed the actuation circuit for an inertial sensor, developed a mathematical model to describe its amplitude stability, and experimentally verified the model's accuracy. Experimental results demonstrate that the current design enables the actuation circuit to achieve an amplitude stability of 3.6 ppm/Hz1/2 at 1 mHz, thereby offering theoretical support for achieving a higher amplitude stability in the millihertz frequency band.

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Development and experimental investigation of a high-precision capacitive displacement transducer of the inertial sensor for TianQin

Cited by 6 publications

References 23 publications

Research and Implementation of a Demodulation Switch Signal Phase Alignment System in Dynamic Environments

Research and Implementation of a Demodulation Switch Signal Phase Alignment System in Dynamic Environments

Research on High-Precision Resonant Capacitance Bridge Based on Multiple Transformers

Amplitude stability research and experimental investigation of the actuation circuit of the inertial sensor for space gravitational wave detection

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