Seismic monitoring system and method based on capacitive sensing and electrostatic driving technology

Abstract

The application provides a seismic monitoring system and method based on capacitive sensing and electrostatic driving technology, which comprises a base, an adjusting platform, a front-end electronic system, a protective shell, a sensitive device and an upper computer; the base is fixed on the ground; the protective shell is fixed on the base and covers the base; the adjusting platform is arranged on the upper part of the base; the sensitive device is arranged on the upper part of the adjusting platform and comprises a test mass and an electrode cage; the test mass is fixed on the protective shell through a metal filament, and the metal filament is connected with the front-end electronic system; the electrode cage is fixed on the adjusting platform and is internally provided with electrodes; the front-end electronic system is installed on the side wall of the protective shell, is connected with the upper computer through an upper computer interface and communicates with the upper computer, is connected with an external power supply through a power supply interface, and is connected with the electrodes and the metal filament through a circuit interface. Through high-precision and high-sensitivity position detection and real-time electrostatic driving control, the application realizes real-time measurement of ground vibration information.

Description

Technical Field

[0001] This invention relates to the field of ground motion monitoring technology, specifically to an earthquake monitoring system and method based on capacitive sensing and electrostatic drive technology. Background Technology

[0002] Seismographs are instruments used to detect and record seismic activity, widely applied in earthquake monitoring, geological exploration, and engineering geology. Traditional seismographs typically rely on mechanical or electromagnetic sensors, which have limitations in sensitivity, response speed, and anti-interference capabilities. In recent years, with the rapid development of microelectronics and sensing technologies, seismographs based on capacitive sensors have gradually gained attention. Capacitive sensors sense external vibrations by detecting changes in capacitance, offering advantages such as high sensitivity, low noise, and good linearity. Furthermore, capacitive sensors are simple in structure, small in size, and low in power consumption, making them suitable for integrated and miniaturized designs. In seismograph design, the introduction of electrostatic drive control technology further enhances system performance. Electrostatic drive control uses electrostatic force to precisely control and adjust the sensor, effectively improving the dynamic range and frequency response characteristics of the seismograph. This technology combines the advantages of capacitive sensors, enabling the seismograph to have higher accuracy and reliability when detecting small seismic fluctuations. This invention proposes a seismograph structural design based on capacitive sensing and electrostatic drive control, aiming to overcome the shortcomings of existing technologies and provide an earthquake monitoring solution with high sensitivity, high accuracy, and high reliability. By optimizing the sensor structure and control circuit design, this seismograph can achieve stable detection and analysis of seismic signals in complex environments. Summary of the Invention

[0003] To address the technical problems existing in the background art, the present invention proposes an earthquake monitoring system and method based on capacitive sensing and electrostatic driving technology. Its concept is reasonable, and through high-precision and high-sensitivity position detection and real-time electrostatic driving control, it realizes the real-time measurement of ground vibration information.

[0004] To solve the above-mentioned technical problems, the present invention provides an earthquake monitoring system based on capacitive sensing and electrostatic driving technology, which includes a base, an adjustment platform, a front-end electronic system, a protective shell, a sensing device, and a host computer.

[0005] The base is fixed to the ground; the protective shell is fixed to the base and covers the base.

[0006] The adjustment platform is located inside the protective shell and is matched to the upper part of the base;

[0007] The sensitive device is matched and disposed on the upper part of the adjustment platform, and includes a test mass and an electrode cage; the test mass is fixed to the protective shell by a metal wire, and the metal wire is connected to the front-end electronics system; the electrode cage is matched and fixed on the adjustment platform and electrodes are matched and disposed on its inner side;

[0008] The front-end electronics system is installed on the side wall of the protective housing. It communicates with the host computer through the host computer interface, is connected to an external power source through the power interface, and is connected to the electrodes and the metal wires through the circuit interface.

[0009] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes: an electrode cage comprising an electrode cage shell; the electrode cage shell being matched and fixed to the upper part of the adjustment platform, and being made of metal material with external insulation treatment; the electrode being matched and fixed inside the electrode cage shell and being insulated from the electrode cage shell.

[0010] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes: the electrode cage further comprising a limiting block; the limiting block is matched and fixed inside the outer shell of the electrode cage and is made of insulating material, which is used to limit the initial position of the test mass and prevent the test mass from touching the electrode during the control process, thus preventing a short circuit; the height of the limiting block is designed to be more than 1.5 times the height of the electrode.

[0011] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes an electrode cage shell with through holes to facilitate connection between the electrodes and the front-end electronics system.

[0012] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes: a front-end electronics system further comprising a circuit board matched and disposed inside the protective housing; the circuit board comprising a sensing system, a control system, and a data acquisition system; the sensing system employing a capacitive sensing structure for detecting the position of the test mass within the electrode cage; the control system for controlling the test mass to be positioned at the center of the electrode cage, employing a PID control method with a preload voltage, applying the same preload voltage to each electrode to be controlled, and applying opposite control voltages to opposite electrodes, utilizing the difference in electrostatic force to control the test mass; and the data acquisition system for acquiring signals from the sensing system and the control system.

[0013] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes a front-end electronics system that further includes a circuit protection shell. The circuit protection shell covers the outside of the circuit board and is fixed to the inner wall of the protective shell to protect the circuit board.

[0014] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes: a host computer connected to the data acquisition system via a host computer interface; the host computer is equipped with a data processing system, which is used to save the acquired data and convert the acquired signals into ground vibration levels.

[0015] The earthquake monitoring system based on capacitive sensing and electrostatic drive technology includes an adjustment platform for adjusting the initial positional relationship between the test mass and the electrode cage, which can achieve precise adjustment in six degrees of freedom, namely translation along three axes and rotation around three axes in a spatial rectangular coordinate system.

[0016] An earthquake monitoring method based on capacitive sensing and electrostatic actuation technology, based on the aforementioned earthquake monitoring system based on capacitive sensing and electrostatic actuation technology, specifically includes the following steps:

[0017] 1) Start the seismograph system, perform detection and calibration, detect the current position of the test mass through the sensor system, and if the deviation is too large, adjust the adjustment platform to control the test mass to be close to the center position of the electrode cage shell.

[0018] 2) Due to the change in relative position between the electrode cage shell and the test mass caused by ground vibration, the control system controls the test mass to be located at the center of the electrode cage shell. When the sensor system collects data and the data fluctuates slightly around the equilibrium position, the control voltage value applied to the electrode is collected by the data acquisition system.

[0019] 3) In the data processing system, the control voltage value obtained in step 2) above is processed to further determine the translational acceleration and rotational angular acceleration of the ground vibration.

[0020] The earthquake monitoring method based on capacitive sensing and electrostatic actuation technology, wherein the method for solving the translational acceleration and rotational angular acceleration of ground vibration is as follows:

[0021] Let the detection voltages of the two channels along the X-axis of the spatial rectangular coordinate system be V. X1 V X2 The detection voltages of the two electrodes along the Y-axis in the spatial rectangular coordinate system are V respectively. Y1 V Y2 The translational acceleration of the ground vibration is then expressed as:

[0022]

[0023] The rotational angular acceleration is expressed as:

[0024]

[0025] Where, ε rε is the relative permittivity, ε0 ​​is the permittivity in vacuum, A is the area of ​​a single electrode, and V is the relative permittivity. r denoted as DC bias voltage applied to the electrode, m as mass of the test mass, d0 as nominal gap of the sensitive structure, l as distance from the center point of the test mass to the center point of the electrode on the plane, and J as moment of inertia of the test mass.

[0026] By adopting the above technical solution, the present invention has the following beneficial effects:

[0027] This invention is logically conceived, combining capacitive sensing and electrostatic drive control technologies. Through high-precision, high-sensitivity position detection and real-time electrostatic drive control, it achieves real-time measurement of ground vibration information. Compared to the connected measurement structure of traditional mechanical seismic monitoring instruments, this invention, through capacitive sensing—a non-contact measurement method—reduces the risk of performance degradation due to wear, aging, or other physical damage. Furthermore, the high-precision displacement sensing via capacitance enables a wider dynamic response range, allowing for the capture of minute vibrations. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the assembly of the sensitive device in this invention;

[0031] Figure 3 This is a flowchart illustrating the usage of the present invention.

[0032] Note:

[0033] 01-Base, 02-Adjustment platform, 03-Front-end electronics system, 031-Host computer interface, 032-Circuit board, 033-Circuit interface, 034-Power interface, 035-Circuit protective shell, 04-Coaxial cable, 05-Protective shell, 06-Metal wire, 07-Sensitive device, 071-Test quality, 072-Limit block, 073-Electrode, 074-Electrode cage shell, 08-Host computer. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] The present invention will be further explained below with reference to specific embodiments.

[0036] To address the limitations of traditional mechanical or electromagnetic seismographs in terms of sensitivity, response speed, and anti-interference capabilities, this study combines capacitive sensing and electrostatic drive control technologies. Through high-precision, high-sensitivity position detection and real-time electrostatic drive control, real-time measurement of ground vibration information is achieved.

[0037] like Figure 1 As shown, this embodiment provides an earthquake monitoring system based on capacitive sensing and electrostatic driving technology, including a base 01, an adjustment platform 02, a front-end electronics system 03, a coaxial cable 04, a protective shell 05, a metal filament 06, a sensing device 07, and a host computer 08.

[0038] The base 01 is fixed to the ground with screws.

[0039] The protective housing 05 serves to insulate and shield against interference, and it is fixed to the base 01 and covers the base 01.

[0040] The adjustment platform 02 is located inside the protective housing 05 and is matched to the upper center of the base 01. It can achieve precise adjustment in six degrees of freedom, namely, fine adjustment of translation along three axes and rotation around three axes in a spatial rectangular coordinate system. In this embodiment, the adjustment platform 02 can achieve adjustment of six degrees of freedom: translation along the X, Y, and Z axes and rotation around the X, Y, and Z axes. The main function of the adjustment platform 02 is to adjust the initial positional relationship between the test mass 071 of the sensing device 07 and the electrode cage, ensuring that the test mass 071 is as close as possible to the center of the electrode 073 of the sensing device 07.

[0041] The sensitive device 07 is positioned at the center of the upper part of the adjustment platform 02, and includes a test mass 071 and an electrode cage. The electrode cage includes a limiting block 072, an electrode 073, and an electrode cage housing 074. The electrode cage housing 074 is made of metal and has an external insulating treatment, and is fixed to the adjustment platform 02 with screws. A through hole is opened in the center of the electrode cage housing 074 for connecting the electrode 073 to the front-end electronics system 03. The electrode 073 is fixed inside the electrode cage housing 074 and is insulated from it. The electrode 073 is a cuboid structure made of metal. The test mass 071 is designed as a metal cube structure, which is fixed to the top center of the protective housing 05 by a flexible metal wire 06. The metal wire 06 is connected to the circuit interface 033 in the front-end electronics system 03 to provide excitation to the detection circuit. The limiting block 072 is made of insulating material and designed as a cube. It is fixed inside the electrode cage shell 074 to limit the initial position of the test mass 071. The height of the limiting block 072 must be greater than the height of the electrode 073. Simultaneously, it prevents the test mass 071 from touching the electrode 073 during control, thus preventing a short circuit. To better achieve the limiting effect, in this embodiment, the limiting blocks 072 are installed at the center of the two electrodes 073 on each plane, for a total of six blocks. The height of the limiting blocks 072 is designed to be at least 1.5 times the height of the electrode 073 (2 times in this embodiment). To facilitate connection with the front-end electronics system 03, a connecting structure is attached to the electrode 073, passing through the through-hole of the electrode cage shell 074 to maintain electrical connection with the electrode 073, and an interface is led out to connect to the front-end electronics system 03 via a coaxial cable 04. When ground vibration occurs, due to the effect of the metal filament 06, the relative positional relationship between the test mass 071 and the electrode 073 will change. With the help of the sensitive structure, the conversion of seismic signals into displacement signals can be realized.

[0042] like Figure 2 This is a schematic diagram of the assembly of the sensing device 07 in this embodiment. The electrode 073 is processed into a metal cuboid structure. The electrode 073 is closely attached to the interior of the six surfaces of the electrode cage shell 074, with two electrodes 073 attached to each surface, for a total of twelve electrodes 073. The electrodes 073 are symmetrically distributed on opposite surfaces of the electrode cage shell 074. The distribution of the electrodes 073 in this embodiment is as follows: Figure 2As shown, four electrodes 073 are distributed along each axis. Each pair of opposing electrodes 073 forms a pathway. Electrodes 073 are distinguished by their positive and negative orientations; the electrode 073 in the positive direction of the coordinate axis is designated as the positive electrode, and the electrode 073 in the negative direction is designated as the negative electrode. In the horizontal direction, electrodes 073 are distributed left-right on one pair of planes and up-down on another pair of planes. The axis of the left-right distribution plane is denoted as the X-axis, and the axis of the up-down distribution plane is denoted as the Y-axis. In the vertical direction, two pairs of electrodes 073 are distributed parallel to the Y-axis, and the vertical direction is denoted as the Z-axis. Of the twelve electrodes, the two pairs of electrodes 073 along the X-axis are used to detect the translation of the test mass 071 along the X-axis and its rotation around the Z-axis; the two pairs of electrodes 073 along the Y-axis are used to detect the translation of the test mass 071 along the Y-axis and its rotation around the X-axis; and the two pairs of electrodes 073 along the Z-axis are used to detect the translation of the test mass 071 along the Z-axis and its rotation around the Y-axis. For example, there are two paths distributed along the X-axis, denoted as X1 and X2. The two electrodes 073 in the positive direction of the X-axis are denoted as X1+ and X2+, and the two electrodes 073 in the negative direction of the X-axis are denoted as X1- and X2-. The electrodes 073 are electrically insulated from the electrode cage shell 074.

[0043] The front-end electronics system 03 is mounted on the side wall of the protective housing 05, and includes a host computer interface 031, a circuit board 032, a circuit interface 033, a power interface 034, and a circuit protective housing 035. The host computer interface 031 is located on the outer side wall of the protective housing 05 and connected to a host computer 08 for communication. The circuit board 032 is located on the inner side wall of the protective housing 05 and includes a sensing system, a control system, and a data acquisition system. The sensing system uses a capacitive sensing structure to detect the position of the test mass 071 within the electrode cage. The control system controls the test mass 071 to be centered within the electrode cage. This control system uses a PID control method with a preload voltage, applying the same preload voltage to each electrode 073 and opposite control voltages to opposite electrodes, utilizing the difference in electrostatic force to control the test mass 071. The data acquisition system is used to acquire signals from the sensing system and the control system. The circuit interface 033 is mounted on the outside of the circuit protective housing 035 and is mainly used for electrical connection with the sensing device 07. There are thirteen in total. Twelve of the circuit interfaces 033 are connected to the electrodes 073 of the sensing device 07 via coaxial cables 04, and one circuit interface 033 is connected to a thin metal wire 06 to provide an excitation signal. The power interface 034 is used to connect a power supply to power the system. The circuit protective housing 035 covers the outside of the circuit board 032 and is fixed to the inner wall of the protective housing 05 to protect the circuit board 032.

[0044] The host computer 08 is equipped with a data processing system, which mainly includes a data storage module and a data processing module. The host computer 08 is connected to the data acquisition system of the circuit board 032 of the front-end electronics system 03 through the host computer interface 031 (using a USB interface) to store the acquired data and realize the conversion of the acquired signal into the ground vibration level.

[0045] like Figure 3 As shown, the earthquake monitoring method based on capacitive sensing and electrostatic actuation technology of the present invention specifically includes the following steps:

[0046] S100. Start the seismograph system, perform detection and calibration, detect the current position of test mass 071 through the sensor system, if the deviation is too large, adjust the adjustment platform 02 to control test mass 071 to approach the center position of electrode cage shell 074.

[0047] S200. Due to ground vibration, the relative position of the electrode cage shell 074 and the test mass 071 will change. The control system controls the test mass to be located at the center of the electrode cage shell 074. When the data collected by the sensing system fluctuates slightly around the equilibrium position, the control voltage values ​​of the X1, X2, Y1, and Y2 channels of the electrode 073 are collected by the data acquisition system.

[0048] S300. In the data processing system, the control data is processed to further determine the translational acceleration and rotational angular acceleration of the ground vibration. The specific solution method is as follows: Let the detection voltages of the two channels on the X-axis be V... X1 V X2 The detection voltages of the two electrodes on the Y-axis are V respectively. Y1 V Y2 The translational acceleration of ground vibration can then be expressed as:

[0049]

[0050] Rotational angular acceleration can be expressed as:

[0051]

[0052] Where, ε r ε is the relative permittivity, ε0 ​​is the permittivity in vacuum, A is the area of ​​a single electrode, and V is the relative permittivity. r d0 is the DC bias voltage applied to the electrode, m is the mass of the test mass, d0 is the nominal gap of the sensitive structure, l is the distance from the center point of the test mass to the center point of the electrode on the plane, and j is the moment of inertia of the test mass.

[0053] Because air is present within the system, during the electrostatic drive control of the test mass, the test mass experiences additional air damping while receiving electrostatic force, leading to certain errors in the test results. To adapt to high-precision application environments, another optimization of this invention involves replacing the protective shell with a high-strength vacuum protective cover. Before the test begins, a vacuum pump is used to evacuate the system and maintain a vacuum environment inside the structure, which can significantly reduce the impact of air damping.

[0054] This invention is well-conceived and achieves real-time measurement of ground vibration information through high-precision, high-sensitivity position detection and real-time electrostatic drive control.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An earthquake monitoring system based on capacitive sensing and electrostatic actuation technology, characterized in that: The earthquake monitoring system includes a base (01), an adjustment platform (02), a front-end electronics system (03), a protective shell (05), a sensing device (07), and a host computer (08); The base (01) is fixed to the ground; the protective shell (05) is fixed to the base (01) and covers the base (01); The adjustment platform (02) is located inside the protective shell (05) and is matched and disposed on the upper part of the base (01); The sensitive device (07) is matched and disposed on the upper part of the adjustment platform (02), and includes a test mass (071) and an electrode cage; the test mass (071) is fixed to the protective shell (05) by a metal wire (06), and the metal wire (06) is connected to the front-end electronics system (03); the electrode cage is matched and fixed on the adjustment platform (02) and an electrode (073) is matched and disposed on its inner side; The front-end electronics system (03) is matched and installed on the side wall of the protective shell (05). It is connected and communicates with the host computer (08) through the host computer interface (031), connected to an external power supply through the power interface (034), and connected to the electrode (073) and the metal wire (06) through the circuit interface (033). The front-end electronics system (03) also includes a circuit board (032) matched and disposed inside the protective housing (05); the circuit board (032) includes a sensing system, a control system and a data acquisition system; the sensing system adopts a capacitive sensing structure to detect the position of the test mass (071) in the electrode cage; the control system is used to control the test mass (071) to be in the center position of the electrode cage, and adopts a PID control method with preload voltage, applying the same preload voltage to each electrode (073) to be controlled, and applying opposite control voltages to the opposite electrodes (073), using the difference in electrostatic force to achieve the control of the test mass (071); the data acquisition system is used to realize the signal acquisition of the sensing system and the control system.

2. The earthquake monitoring system based on capacitive sensing and electrostatic drive technology as described in claim 1, characterized in that: The electrode cage includes an electrode cage shell (074). The electrode cage shell (074) is fixed to the upper part of the adjustment platform (02), and it is made of metal material and has an external insulation treatment; The electrode (073) is fixed to the inside of the electrode cage shell (074) and is insulated from the electrode cage shell (074).

3. The earthquake monitoring system based on capacitive sensing and electrostatic drive technology as described in claim 2, characterized in that: The electrode cage also includes a limiting block (072); The limiting block (072) is matched and fixed inside the electrode cage shell (074) and is made of insulating material. It is used to limit the initial position of the test mass (071) and prevent the test mass (071) from touching the electrode (073) during the control process, thus preventing a short circuit. The height of the limiting block (072) is designed to be more than 1.5 times the height of the electrode (073).

4. The earthquake monitoring system based on capacitive sensing and electrostatic drive technology as described in claim 2, characterized in that: The electrode cage housing (074) has through holes for easy connection between the electrode (073) and the front-end electronics system (03).

5. The earthquake monitoring system based on capacitive sensing and electrostatic drive technology as described in claim 1, characterized in that: The front-end electronics system (03) also includes a circuit protection shell (035); the circuit protection shell (035) covers the outside of the circuit board (032) and is fixed to the inner wall of the protective shell (05) to protect the circuit board (032).

6. The earthquake monitoring system based on capacitive sensing and electrostatic actuation technology as described in claim 1, characterized in that: The host computer (08) is connected to the data acquisition system through the host computer interface (031); the host computer (08) is equipped with a data processing system, which is used to save the acquired data and realize the conversion of the acquired signal into the ground vibration level.

7. The earthquake monitoring system based on capacitive sensing and electrostatic actuation technology as described in claim 1, characterized in that: The adjustment platform (02) is used to adjust the initial position relationship between the test mass (071) and the electrode cage, and can achieve precise adjustment in six degrees of freedom, namely translation along three axes and rotation around three axes in a spatial rectangular coordinate system.

8. A seismic monitoring method based on capacitive sensing and electrostatic actuation technology, based on the seismic monitoring system based on capacitive sensing and electrostatic actuation technology according to any one of claims 1 to 7, characterized in that, Specifically, the following steps are included: 1) Start the seismograph system, perform detection and calibration, detect the current position of the test mass (071) through the sensor system, if the deviation is too large, control the test mass (071) to be close to the center position of the electrode cage shell (074) by adjusting the adjustment platform (02); 2) Due to ground vibration, the relative position of the electrode cage shell (074) and the test mass (071) will change. The test mass (071) is controlled by the control system to be located at the center of the electrode cage shell (074). When the data collected by the sensing system fluctuates slightly around the equilibrium position, the control voltage value applied to the electrode (073) is collected by the data acquisition system. 3) In the data processing system, the control voltage value obtained in step 2) above is processed to further determine the translational acceleration and rotational angular acceleration of the ground vibration.

9. The earthquake monitoring method based on capacitive sensing and electrostatic actuation technology as described in claim 8, characterized in that: The methods for solving the translational acceleration and rotational angular acceleration of the ground vibration are as follows: Let the detection voltages of the two channels along the X-axis of the spatial rectangular coordinate system be V. X1 V X2 The detection voltages of the two electrodes along the Y-axis in the spatial rectangular coordinate system are V respectively. Y1 V Y2 The translational acceleration of the ground vibration is then expressed as: ， The rotational angular acceleration is expressed as: ， in, The relative permittivity, The dielectric constant in vacuum. The area of ​​a single electrode. The DC bias voltage applied to the electrodes. For the quality of the test, The nominal gap of the sensitive structure, The distance from the center point of the test mass to the center point of the electrode on the plane. The moment of inertia of the test mass.

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