High-precision pendulous accelerometer

• US 10,309,984 B2
• Filed: 06/28/2018
• Issued: 06/04/2019
• Est. Priority Date: 02/25/2016
• Status: Active Grant

• Current Assignee: institute of geology and geophysics, chinese academy of sciences (Chinese Academy of Sciences)
• Original Assignee: institute of geology and geophysics, chinese academy of sciences (Chinese Academy of Sciences)
• Inventors: Xue, Xu
• Primary Examiner(s): Kwok, Helen C
• Application Number:
  US16/022,331
• Publication Number:
  US 20180306835A1
• Time in Patent Office: 341 Days
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/13 by measuring the force required to restore a proofmass subjected to inertial forces to a null position
• CPC Class Codes: G01P 15/131 with electrostatic counterbalancing means
• CPC Class Codes: G01P 15/132 with electromagnetic counterbalancing means

Abstract

Provided is a quartz pendulous accelerometer including a quartz meter configured to sense an acceleration signal, convert the acceleration signal into an inertia torque, and convert the inertia torque into a quartz meter output signal; a readout apparatus configured to convert the meter output signal into an input signal recognizable by a pulse generating apparatus; and a pulse generating apparatus configured to perform control algorithm conversion, oversampling and digital quantization on the input signal to obtain a quantized current pulse, which is converted into an electromagnetic pulse torque for balancing the inertia torque.

Claims

1. A quartz pendulous accelerometer, comprising:

a quartz meter, which is configured to sense an acceleration signal, and convert the acceleration signal into an inertia torque and convert the inertia torque into a meter output signal;

a capacitance-to-voltage (C-V) readout circuit, which is configured to convert the meter output signal into an input signal recognizable by a pulse generating apparatus; and

the pulse generating apparatus, which is configured to perform control algorithm conversion, oversampling and digital quantization on the input signal to obtain a quantized current pulse,

wherein the quantized current pulse is an oversampled modulated signal comprising information about a magnitude and a polarity of a feedback force and is converted into an electromagnetic pulse torque for balancing the inertia torque.

2. The quartz pendulous accelerometer according to claim 1, wherein the pulse generating apparatus comprises a control algorithm unit, an oversampling unit, and a digital quantization unit.

3. The quartz pendulous accelerometer according to claim 2, wherein the oversampling unit is configured to perform oversampling on the input signal recognizable by the pulse generating apparatus;

the control algorithm unit is configured to convert the oversampled input signal into a control signal, the input signal being a voltage signal; and

the digital quantization unit is configured to quantize the control signal into an output bit stream signal.

4. The quartz pendulous accelerometer according to claim 2, wherein the control algorithm unit is configured to perform control algorithm conversion to convert the input signal recognizable by the pulse generating apparatus into a control signal;

the oversampling unit is configured to perform oversampling on the control signal; and

the digital quantization unit is configured to perform digital quantization to quantize the oversampled control signal into an output bit stream signal.

5. The quartz pendulous accelerometer according to claim 1, wherein the quartz pendulous accelerometer further comprises an electromagnetic torque pulse control unit.

6. The quartz pendulous accelerometer according to claim 5, wherein the electromagnetic torque pulse control unit comprises a timing control unit and a constant-current source unit.

7. The quartz pendulous accelerometer according to claim 6, wherein the electromagnetic torque pulse control unit receives the quantized current pulse, and the timing control unit determines a direction and a magnitude of the acceleration signal by switching a conduction direction and a number of conduction periods of the constant-current source unit, and performs feedback control on an electromagnetic torquer of the quartz meter for balancing the inertia torque.

8. The quartz pendulous accelerometer according to claim 1, wherein the quantized current pulse is a bit stream signal.

9. The quartz pendulous accelerometer according to claim 1, wherein the meter output signal is a capacitance signal, and the C-V readout circuit converts the capacitance signal into a voltage signal recognizable by the pulse generating apparatus.

10. The quartz pendulous accelerometer according to claim 3, wherein the control algorithm unit comprises a compensation unit, which performs phase compensation on a closed-loop circuit of the quartz pendulous accelerometer.

11. The quartz pendulous accelerometer according to claim 1, wherein the quartz meter mainly comprises a quartz pendulum, a torquer yoke, a torquer coil and a magnet;

and

wherein the quartz pendulum and end faces of the torquer yoke make up differential capacitors, an upper gold-plated face and a lower gold-plated face of the quartz pendulum act as movable polar plates of the differential capacitors, and the torquer yoke acts as stationary polar plates of the differential capacitors.

12. The quartz pendulous accelerometer according to claim 1, wherein the quartz pendulous accelerometer further comprises a filtering and decimating unit, which is configured to perform down-sampling and filtering on the quantized current pulse to output a digital quantity signal.

13. A closed-loop control method for a quartz pendulous accelerometer, the method comprising:

providing a quartz meter, which is configured to sense an acceleration signal, and convert the acceleration signal into an inertia torque and convert the inertia torque into a meter output signal;

converting, using a capacitance-to-voltage (C-V) readout circuit, the meter output signal into an input signal recognizable by a pulse generating apparatus and inputting the input signal to the pulse generating apparatus; and

performing control algorithm conversion, oversampling and digital quantization on the input signal to obtain a quantized current pulse,

wherein the quantized current pulse is an oversampled modulated signal comprising information about a magnitude and a polarity of a feedback force and is converted into an electromagnetic pulse torque for balancing the inertia torque.

14. The closed-loop control method for a quartz pendulous accelerometer according to claim 13, wherein the pulse generating apparatus sequentially performs oversampling, control algorithm conversion, and digital quantization on the input signal to output the quantized current pulse.

15. The closed-loop control method for a quartz pendulous accelerometer according to claim 13, wherein the pulse generating apparatus sequentially performs control algorithm conversion, oversampling, and digital quantization on the input signal to output the quantized current pulse.

16. The closed-loop control method for a quartz pendulous accelerometer according to claim 14, further comprising:

providing an oversampling unit, which is configured to perform oversampling on the input signal;

providing a control algorithm unit, which is configured to convert the oversampled input signal into a control signal; and

providing a digital quantization unit, which is configured to quantize the control signal into an output bit stream.

17. The closed-loop control method for a quartz pendulous accelerometer according to claim 15, further comprising:

providing a control algorithm unit, which is configured to convert the input signal into a control signal;

providing an oversampling unit, which is configured to convert the control signal into an oversampled control signal; and

providing a digital quantization unit, which is configured to quantize the oversampled control signal into an output bit stream.

18. The closed-loop control method for a quartz pendulous accelerometer according to claim 13,

wherein the meter output signal is a capacitance signal, and the input signal recognizable by the pulse generating apparatus is a voltage signal;

and

the capacitance signal is converted into a voltage signal recognizable by the pulse generating apparatus using the C-V readout circuit.

19. The closed-loop control method for a quartz pendulous accelerometer according to claim 13, the method further comprising:

providing an electromagnetic torque pulse control unit, which comprises a timing control unit and a constant-current source unit;

wherein the electromagnetic torque pulse control unit receives the quantized current pulse, and

wherein the timing control unit determines a direction and a magnitude of the acceleration signal by switching a conduction direction and a number of conduction times of the constant-current source unit by timing control, and performs feedback control on an electromagnetic torquer of the quartz meter for balancing the inertia torque.

20. The closed-loop control method for a quartz pendulous accelerometer according to claim 16, further comprising:

providing a compensation unit, which is configured to perform phase compensation on a closed-loop circuit of the quartz pendulous accelerometer.

21. The closed-loop control method for a quartz pendulous accelerometer according to claim 13, wherein the quantized current pulse is a bit stream signal.