A temperature drift resistant, high-sensitivity micro-vibration sensor and its measurement circuit

Abstract

This invention discloses a high-sensitivity micro-vibration sensor with resistance to temperature drift and its measurement circuit, including a vibration sensing module and a measurement circuit module. The signal output from the vibration sensing module is conditioned by the measurement circuit module and then enters the data acquisition device. By adopting a two-stage piezoelectric dual-crystal design for the sensor, the sensor's measurement sensitivity can be improved by connecting two piezoelectric dual-crystals in series with the same central mass, thereby increasing the sensitive area of ​​the piezoelectric material and improving the sensor's measurement sensitivity, thus resolving the contradiction between high sensitivity and high-frequency measurement performance. By adopting the piezoelectric dual-crystal design and the precise differential amplification design of the piezoelectric dual-crystal output signal in the measurement circuit, the influence of the temperature effect of the piezoelectric material on the sensor's low-frequency measurement performance can be avoided. Through the micro-vibration sensor and measurement circuit design provided by this invention, high-precision measurement of minute vibrations over a wide frequency range can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, specifically relating to a high-sensitivity micro-vibration sensor with resistance to temperature drift and its measurement circuit. Background Technology

[0002] Piezoelectric vibration sensors work by utilizing the piezoelectric effect of piezoelectric ceramics or quartz crystals to convert vibration acceleration into an electrical signal for measurement. They are characterized by small size, good dynamic response characteristics, and strong anti-interference capabilities, and are widely used in vibration measurement and control systems. The ever-increasing demands for vibration measurement and control in precision equipment place higher demands on sensor technical specifications, requiring sensors to have lower measurement frequencies and higher measurement sensitivity.

[0003] The low-frequency measurement performance of piezoelectric vibration sensors is mainly affected by the temperature effect of the piezoelectric material. This temperature effect induces low-frequency drift in the sensor's measurement signal, causing low-frequency measurement distortion. Currently, a common approach is to filter the low-frequency signal using a high-pass filter module in the subsequent signal conditioning circuit. However, this method also filters out useful low-frequency vibration signals, limiting the sensor's low-frequency measurement bandwidth. Alternatively, adding a compensation unit to the sensor for active compensation to eliminate the effect of temperature drift is also an option; however, the introduction of active compensation control significantly increases the sensor's cost and implementation complexity. Furthermore, for a piezoelectric vibration sensor made of a given piezoelectric material, its sensitivity increases with increasing central mass. However, the central mass is limited by the sensor's size and mass, and increasing the central mass lowers the sensor's natural frequency, thus affecting the sensor's high-frequency measurement performance. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a temperature-drift-resistant, high-sensitivity micro-vibration sensor and its measurement circuit, including a vibration sensing module and a measurement circuit module. The signal output from the vibration sensing module is conditioned by the measurement circuit module before entering the data acquisition device. By employing a two-stage piezoelectric dual-crystal design, the sensor's measurement sensitivity can be improved by connecting two piezoelectric dual-crystals in series with the same central mass, thereby increasing the sensitive area of ​​the piezoelectric material and resolving the contradiction between high sensitivity and high-frequency measurement performance. Through the piezoelectric dual-crystal design and the precise differential amplification design of the piezoelectric dual-crystal output signal in the measurement circuit, the influence of piezoelectric material temperature effects on the sensor's low-frequency measurement performance can be avoided, while simultaneously enabling precise amplification of the sensor's weak measurement signal for subsequent acquisition. Through the micro-vibration sensor and measurement circuit design provided by this invention, high-precision measurement of minute vibrations over a wide frequency range is ultimately achieved.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows:

[0006] A temperature-drift-resistant, high-sensitivity micro-vibration sensor and its measurement circuit are disclosed, comprising a vibration sensing module and a measurement circuit module; the signal output by the vibration sensing module is conditioned by the measurement circuit module and then enters a data acquisition device.

[0007] The vibration sensing module includes a piezoelectric bicrystalline wafer P1, a piezoelectric bicrystalline wafer P2, a central mass block, a shell, an upper top plate, a lower top plate, and a base;

[0008] The piezoelectric bicrystalline wafers P1 and P2 and the central mass block are installed inside the housing; the piezoelectric bicrystalline wafer P1 is connected to the upper surface of the central mass block, and the piezoelectric bicrystalline wafer P2 is connected to the lower surface of the central mass block; the upper and lower ends of the housing are fixedly connected to the upper and lower top plates, respectively; the vibration sensing module is connected to the object being measured through the base.

[0009] The piezoelectric bicrystalline wafers P1 and P2 have the same specifications;

[0010] Both the piezoelectric bicrystalline wafer P1 and the piezoelectric bicrystalline wafer P2 are composed of three parts: an upper piezoelectric sheet, a lower piezoelectric sheet, and a middle metal sheet. The upper piezoelectric sheet is the upper electrode, the lower piezoelectric sheet is the lower electrode, and the middle metal sheet is the common electrode. They are led out from the wire outlet hole on the outer shell through cables.

[0011] The measurement circuit module includes a DC blocking circuit A, a DC blocking circuit B, a differential amplifier S1, a differential amplifier S2, an adder circuit, and a low-pass filter circuit.

[0012] The DC blocking circuit A and DC blocking circuit B are symmetrically arranged, each including two capacitors C1 and two resistors R1 of the same specifications arranged symmetrically; the differential amplifier S1 and differential amplifier S2 are symmetrically arranged; the adder circuit includes two resistors R2 and R3 of the same specifications arranged symmetrically, a precision voltage operational amplifier M and a resistor R4; the filter circuit includes a resistor R5 and a capacitor C2.

[0013] In the vibration sensing module, piezoelectric bicrystalline wafers P1 and P2 respectively generate two positive and negative voltage signals representing vibration information, which are then fed into DC blocking circuit A and DC blocking circuit B respectively via cables.

[0014] One end of each of the two capacitors C1 in the DC blocking circuit A is connected to the positive and negative signal interfaces of the piezoelectric bicrystalline silicon P1, and the other end of each capacitor C1 is connected to the differential positive and negative input terminals of the differential amplifier S1, respectively; one end of each of the two resistors R1 is connected to the differential positive and negative input terminals of the differential amplifier S1, and the other end is grounded.

[0015] One end of the two capacitors C1 in the DC blocking circuit B is connected to the positive and negative signal interfaces of the piezoelectric bicrystalline silicon P2, respectively. The other end of the two capacitors C1 is connected to the differential positive and negative input terminals of the differential amplifier S2, respectively. One end of the two resistors R1 is connected to the differential positive and negative input terminals of the differential amplifier S2, respectively, and the other end is grounded.

[0016] The output terminals of differential amplifier S1 and differential amplifier S2 are respectively connected to the left ends of resistors R2 and R3. The right end of resistor R2 is connected to the negative input terminal of precision voltage operational amplifier M. The right end of resistor R3 is connected to the right end of resistor R2. The positive input terminal of precision voltage operational amplifier M is grounded. The two ends of resistor R4 are respectively connected between the right end of resistor R2 and the output terminal of precision voltage operational amplifier M.

[0017] The two ends of the resistor R5 are respectively connected to the output of the precision voltage operational amplifier M and the output of the measurement circuit module; one end of the capacitor C2 is connected to the right end of the resistor R5, and the other end is grounded.

[0018] Preferably, the differential amplifier S1 and the differential amplifier S2 are of the same specifications.

[0019] Preferably, resistors R2, R3, and R4 have the same specifications.

[0020] Preferably, mounting bosses are provided on the upper and lower positions of the inner wall of the housing, and the piezoelectric bicrystalline wafers P1 and P2 are respectively placed on the mounting bosses on the upper and lower positions of the inner wall of the housing.

[0021] Preferably, the piezoelectric bicrystalline wafers P1 and P2 are connected and fixed to the upper and lower surfaces of the central mass block by bolts.

[0022] Preferably, the upper and lower piezoelectric sheets of the piezoelectric bicrystalline wafer are of the same specifications.

[0023] Preferably, the upper and lower top plates are designed with external threads, the outer shell is designed with internal threads, and the upper and lower top plates are connected to the outer shell by threads; the outer surfaces of the upper and lower top plates are designed with mounting grooves, and are rotated and installed by tooling.

[0024] Preferably, the upper top plate cooperates with the upper mounting boss on the inner wall of the outer shell to clamp and fix the edge of the piezoelectric bicrystalline wafer P1, and the lower top plate cooperates with the lower mounting boss on the inner wall of the outer shell to clamp and fix the edge of the piezoelectric bicrystalline wafer P2.

[0025] Preferably, the piezoelectric element is made of low-capacitance quartz material.

[0026] The beneficial effects of this invention are as follows:

[0027] (1) The present invention adopts a two-stage piezoelectric dual-crystal design, which can improve the measurement sensitivity of the sensor under the same size and mass. The sensitivity is increased by four times compared with the single-stage, single-crystal design, while ensuring the high-frequency measurement performance of the sensor.

[0028] (2) The present invention can effectively avoid the influence of the temperature effect of piezoelectric material on the low-frequency measurement accuracy of sensor by differential processing of the positive and negative signals of the upper and lower piezoelectric plates of the piezoelectric bicrystalline wafer.

[0029] (3) In the measurement circuit of the present invention, the constant deviation of the output signal of the piezoelectric bicrystalline wafer is isolated by the DC blocking circuit and then precisely amplified, which can improve the effective measurement amplitude of the sensor and realize high-precision measurement of the sensor’s tiny signals. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the micro-vibration sensor structure of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure and output signal of the piezoelectric bicrystalline wafer of the present invention;

[0032] Figure 3 This is a schematic diagram of the measurement circuit of the micro-vibration sensor of the present invention.

[0033] Reference numerals: 1: Piezoelectric bicrystalline wafer P1, 2: Piezoelectric bicrystalline wafer P2, 3: Central mass block, 4: Outer shell, 5: Upper top plate, 6: Lower top plate, 1-1: Upper piezoelectric sheet, 1-2: Upper piezoelectric sheet, 1-3: Middle metal sheet, a: Upper electrode of piezoelectric bicrystalline wafer, b: Lower electrode of piezoelectric bicrystalline wafer, c: Common electrode of piezoelectric bicrystalline wafer. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0035] The purpose of this invention is to provide a high-sensitivity micro-vibration sensor with temperature drift suppression and a matching measurement circuit. By employing a two-stage piezoelectric dual-crystal design, the sensor's measurement sensitivity can be improved by connecting two piezoelectric dual-crystals in series with the same central mass, thereby increasing the sensitive area of ​​the piezoelectric material and resolving the contradiction between high sensitivity and high-frequency measurement performance. Furthermore, by using the piezoelectric dual-crystal design and a precise differential amplification design for the piezoelectric dual-crystal output signal in the measurement circuit, the influence of piezoelectric material temperature effects on the sensor's low-frequency measurement performance can be avoided, while simultaneously enabling precise amplification of the sensor's weak measurement signal for subsequent acquisition. Through the micro-vibration sensor and measurement circuit design provided by this invention, high-precision measurement of minute vibrations over a wide frequency range is ultimately achieved.

[0036] To achieve the above objectives, the present invention provides the following technical solution:

[0037] A high-sensitivity micro-vibration sensor with resistance to temperature drift and its measurement circuit include a vibration sensing module and a measurement circuit module. The signal output by the vibration sensing module is conditioned by the measurement circuit module and then enters other data acquisition devices.

[0038] The vibration sensing module includes a piezoelectric bicrystalline wafer P1, a piezoelectric bicrystalline wafer P2, a central mass block, a housing, an upper top plate, a lower top plate, and a base. The piezoelectric bicrystalline wafers P1 and P2 and the central mass block are installed inside the housing. Mounting bosses are respectively provided on the upper and lower positions of the inner wall of the housing. The piezoelectric bicrystalline wafers P1 and P2 are placed on the upper and lower mounting bosses of the inner wall of the housing, respectively. P1 is connected to the upper surface of the central mass block, and P2 is connected to the lower surface of the central mass block. The two ends of the housing are fixed to the upper and lower top plates, respectively.

[0039] The piezoelectric bicrystalline wafers P1 and P2 are connected and fixed to the upper and lower surfaces of the central mass block by bolts.

[0040] The piezoelectric bicrystalline wafers P1 and P2 have the same specifications;

[0041] The piezoelectric bicrystalline wafers P1 and P2 are each composed of three parts: an upper piezoelectric sheet, a lower piezoelectric sheet, and a middle metal sheet. The upper piezoelectric sheet is the upper electrode, the lower piezoelectric sheet is the lower electrode, and the middle metal sheet is the common electrode. They are led out from the wire outlet hole on the outer shell through cables.

[0042] The upper and lower piezoelectric sheets of the piezoelectric bicrystalline wafer are of the same specifications;

[0043] The upper and lower top plates are designed with external threads, and the outer shell is designed with internal threads. The upper and lower top plates are connected to the outer shell by threads. The outer surfaces of the upper and lower top plates are designed with mounting grooves for rotational installation using tooling.

[0044] The upper top plate cooperates with the upper mounting boss on the inner wall of the outer shell to clamp and fix the edge of the piezoelectric bicrystalline wafer P1, and the lower top plate cooperates with the lower mounting boss on the inner wall of the outer shell to clamp and fix the edge of the piezoelectric bicrystalline wafer P2.

[0045] The measurement circuit module includes DC blocking circuits (A and B), differential amplifiers (S1 and S2), an adder circuit, and a low-pass filter circuit, all integrated on the same circuit board and connected sequentially. DC blocking circuits A and B are symmetrically arranged, each including two capacitors C1 and two resistors R1 of the same specifications, also symmetrically arranged. The differential amplifiers S1 and S2 are symmetrically arranged. The adder circuit includes two resistors R2 and R3 of the same specifications, a precision voltage operational amplifier M, and a resistor R4. The filter circuit includes a resistor R5 and a capacitor C2.

[0046] Due to external influences, the piezoelectric bicrystalline wafers P1 and P2 in the vibration sensing module generate two positive and negative voltage signals representing vibration information, which are then transmitted to the DC blocking circuit A and DC blocking circuit B via cables, respectively.

[0047] In DC blocking circuit A, one end of each of the two capacitors C1 is connected to the positive and negative signal interfaces of the piezoelectric bicrystalline silicon P1, and the other end is connected to the differential positive and negative input terminals of the differential amplifier S1. One end of each of the two resistors R1 is connected between the capacitors C1 and the differential positive and negative input terminals of the differential amplifier S1, and the other end is grounded. In DC blocking circuit B, one end of each of the two capacitors C1 is connected to the positive and negative signal interfaces of the piezoelectric bicrystalline silicon P2, and the other end is connected to the differential positive and negative input terminals of the differential amplifier S2. One end of each of the two resistors R1 is connected between the capacitors C1 and the differential positive and negative input terminals of the differential amplifier S2, and the other end is grounded.

[0048] The output terminals of the differential amplifier S1 and differential amplifier S2 are respectively connected to the left ends of resistors R2 and R3 in the adder circuit. The right end of resistor R2 is connected to the negative input terminal of the precision voltage operational amplifier M, and the right end of resistor R3 is connected to the right end of resistor R2. The positive input terminal of the precision voltage operational amplifier M is grounded. The two ends of resistor R4 are respectively connected between the right end of resistor R2 and the output terminal of the precision voltage operational amplifier M.

[0049] In the low-pass filter circuit, the two ends of resistor R5 are respectively connected to the output terminal of the precision voltage operational amplifier M and the output terminal of the measurement circuit module. In the low-pass filter circuit, one end of capacitor C2 is connected to the right end of resistor R5, and the other end is grounded.

[0050] The differential amplifier S1 and differential amplifier S2 are of the same specifications.

[0051] The resistors R2, R3, and R4 are of the same specifications.

[0052] Example:

[0053] like Figure 1As shown, a high-sensitivity micro-vibration sensor with resistance to temperature drift includes a piezoelectric bicrystalline wafer 1, a piezoelectric bicrystalline wafer 2, a central mass block 3, a housing 4, an upper top plate 5, and a lower top plate 6. The piezoelectric bicrystalline wafer 1, the piezoelectric bicrystalline wafer 2, and the central mass block 3 are installed inside the housing 4 and sealed by the upper top plate 5 and the lower top plate 6.

[0054] like Figure 2 As shown, the piezoelectric bicrystalline wafer 1 and the piezoelectric bicrystalline wafer 2 are respectively composed of an upper piezoelectric sheet 1-1, a lower piezoelectric sheet 1-2, and an intermediate metal sheet 1-3. The upper piezoelectric sheet 1-1 is the upper electrode a, the lower piezoelectric sheet 1-2 is the lower electrode b, and the intermediate metal sheet 1-3 is the common electrode c.

[0055] The piezoelectric bicrystalline wafers 1 and 2 are designed with central holes at their center positions; the upper and lower parts of the inner wall of the outer shell 4 are respectively provided with mounting bosses, internal threads and wire outlet holes; the upper and lower surfaces of the central mass block 3 are provided with threaded holes at their center positions; the upper top plate 5 and lower top plate 6 are respectively designed with external threads at their edges; the outer surfaces of the upper top plate 5 and lower top plate 6 are respectively designed with mounting grooves at their center positions.

[0056] The piezoelectric bicrystalline wafer 1 is placed on the mounting boss on the upper part of the inner wall of the outer shell 4, and the piezoelectric bicrystalline wafer 1 and the central mass block 3 are bolted together through the central hole of the piezoelectric bicrystalline wafer 1 and the threaded hole on the upper surface of the central mass block 3; the piezoelectric bicrystalline wafer 2 is placed on the mounting boss on the lower part of the inner wall of the outer shell 4, and the piezoelectric bicrystalline wafer 2 and the central mass block 3 are bolted together through the central hole of the piezoelectric bicrystalline wafer 2 and the threaded hole on the lower surface of the central mass block 3.

[0057] The upper top plate 5 is connected to the outer shell 4 by internal and external threads. The upper top plate 5 cooperates with the upper mounting boss on the inner wall of the outer shell 4 to clamp and fix the edge of the piezoelectric bicrystalline wafer 1. The lower top plate 6 is connected to the outer shell 4 by internal and external threads. The lower top plate 6 cooperates with the lower mounting boss on the inner wall of the outer shell 4 to clamp and fix the edge of the piezoelectric bicrystalline wafer 2.

[0058] The upper top plate 5 and the lower top plate 6 can be rotated through the mounting groove and are installed in conjunction with the outer shell 4.

[0059] The output signals of the piezoelectric bicrystalline wafer 1 and piezoelectric bicrystalline wafer 2 are respectively led out from the wire outlet hole on the outer casing 4 through cables;

[0060] In this embodiment, piezoelectric bicrystalline wafer 1 and piezoelectric bicrystalline wafer 2 have the same specifications, and the upper piezoelectric sheet 1-1 and the lower piezoelectric sheet 1-2 have the same specifications. The piezoelectric sheets are made of low-capacitance quartz material.

[0061] When the sensor is subjected to vibration, due to inertia, the central mass block 3 will generate an inertial force proportional to the vibration it experiences, acting on the piezoelectric bicrystalline wafers 1 and 2, thus causing a change in charge. Furthermore, temperature changes will also cause changes in the charge of the piezoelectric wafers, leading to changes in the output voltage. According to the sensor design, the electrode output voltages of the upper piezoelectric wafer 1-1 and the lower piezoelectric wafer 1-2 in piezoelectric bicrystalline wafer 1, and the upper piezoelectric wafer 1-1 and the lower piezoelectric wafer 1-2 in piezoelectric bicrystalline wafer 2, can be expressed as follows:

[0062]

[0063] Among them, Q v and Q T These represent the changes in charge caused by sensor vibration and temperature changes, respectively, with C being the piezoelectric capacitance.

[0064] like Figure 3 As shown, the measurement circuit of the temperature drift resistant and high-sensitivity micro-vibration sensor consists of four parts: DC blocking module I, differential amplification module II, addition module III, and low-pass filter module IV.

[0065] The DC blocking module I includes DC blocking circuit A and DC blocking circuit B, which contain four capacitors C1 and resistors R1 of the same specifications; the differential amplifier module II includes differential amplifier S1 and differential amplifier S2; the adder module III includes resistors R2, R3, and R4 and a precision voltage operational amplifier M; the low-pass filter module IV includes a resistor R5 and a capacitor C2.

[0066] In the DC blocking module I, one end of each of the four capacitors C1 is connected to the signal interfaces of the upper electrode a and lower electrode b of the piezoelectric bicrystalline wafer 1 and the piezoelectric bicrystalline wafer 2, respectively, and the other end is connected to the differential positive and negative input terminals of the differential amplifier S1, respectively. One end of each of the four resistors R1 is connected between the four capacitors C1 and the differential positive and negative input terminals of the differential amplifier S1, and the other end is grounded.

[0067] The DC blocking module I uses an RC filter circuit composed of capacitor C1 and resistor R1 to filter out the DC bias signal in the piezoelectric output voltage. The filter cutoff frequency affects the lower limit measurement frequency of the sensor. By selecting appropriate values ​​for C1 and R1, the low-frequency measurement performance of the sensor can be guaranteed while achieving DC blocking. The filter cutoff frequency of DC blocking module I is f. low =12πR1C1.

[0068] In the differential amplifier module II, differential amplifier S1 outputs voltage V to the piezoelectric bicrystalline wafer 1. 1a and V 1b Differential amplification is performed; the differential amplifier S2, a piezoelectric bicrystalline chip 2, outputs a voltage V.2a and V 2b Differential processing and amplification are performed. Differential processing can remove temperature-induced charge Q. T This reduces the impact of the sensor's voltage sensitivity; simultaneously, a constant differential amplifier gain can be set to amplify the small voltage signal output by the piezoelectric element. The output voltages of differential amplifiers S1 and S2 can be expressed as follows:

[0069] V1=k(V 1a -V 1b )=2kQ v C, V2=k(V 2a -V 2b )=2kQ v C (2)

[0070] Where k is the constant amplification gain of differential amplifier S1 and differential amplifier S2.

[0071] The differential amplifier S1 and differential amplifier S2 are of the same specifications.

[0072] In the addition module III, the left ends of resistors R2 and R3 are connected to the output terminals of differential amplifiers S1 and S2, respectively. The right end of resistor R2 is connected to the negative input terminal of precision voltage operational amplifier M, and the right end of resistor R3 is connected to the right end of resistor R2. The positive input terminal of precision voltage operational amplifier M is grounded. The two ends of resistor R4 are connected between the right end of resistor R2 and the output terminal of precision voltage operational amplifier M, respectively.

[0073] The adder module III adds voltages V1 and V2, thereby improving the sensor's voltage sensitivity. The output voltage of the adder module is:

[0074] V3 = V1 + V2 = 4kQ v C (3)

[0075] In the low-pass filter module IV, the two ends of resistor R5 are connected to the output terminal of precision voltage operational amplifier M and the output terminal of measurement circuit, respectively. One end of capacitor C2 is connected to the right end of resistor R5, and the other end is grounded.

[0076] The low-pass filter module IV uses capacitor C2 and resistor R5 to form an RC filter circuit to filter out high-frequency noise signals in the sensor output voltage. The filter cutoff frequency affects the upper limit measurement frequency of the sensor. The filter cutoff frequency of the low-pass filter module IV is f. high =12πR5C2.

Claims

1. A temperature-drift-resistant high-sensitivity micro-vibration sensor and a measuring circuit thereof, characterized in that, It comprises a vibration sensing module and a measuring circuit module; the signal output by the vibration sensing module is input into a data acquisition device after being conditioned by the measuring circuit module; The vibration sensing module comprises a piezoelectric bimorph P1, a piezoelectric bimorph P2, a center mass, a shell, an upper top plate, a lower top plate and a base; The piezoelectric bimorph P1, the piezoelectric bimorph P2 and the center mass are installed in the shell; the piezoelectric bimorph P1 is connected with the upper surface of the center mass, and the piezoelectric bimorph P2 is connected with the lower surface of the center mass; the upper and lower ends of the shell are fixedly connected with the upper top plate and the lower top plate respectively; the vibration sensing module is connected with the measured object through the base; The piezoelectric bimorph P1 and the piezoelectric bimorph P2 are of the same specification; The piezoelectric bimorph P1 and the piezoelectric bimorph P2 each comprise an upper piezoelectric sheet, a lower piezoelectric sheet and a middle metal sheet; the upper piezoelectric sheet is an upper electrode, the lower piezoelectric sheet is a lower electrode, and the middle metal sheet is a common electrode, which are led out from the outlet holes on the shell through cables respectively; The measuring circuit module comprises a direct-current isolation circuit A, a direct-current isolation circuit B, a differential amplifier S1, a differential amplifier S2, an addition circuit and a low-pass filter circuit; The direct-current isolation circuit A and the direct-current isolation circuit B are symmetrically arranged and each comprises two symmetrically arranged capacitors C1 and two symmetrically arranged resistors R1 of the same specification; the differential amplifier S1 and the differential amplifier S2 are symmetrically arranged; the addition circuit comprises two symmetrically arranged resistors R2 and R3, a precision voltage operational amplifier M and a resistor R4 of the same specification; and the filter circuit comprises a resistor R5 and a capacitor C2; The piezoelectric bimorph P1 and the piezoelectric bimorph P2 in the vibration sensing module respectively generate two positive and negative voltage signals representing vibration information, which are respectively input into the direct-current isolation circuit A and the direct-current isolation circuit B through cables; One end of each of the two capacitors C1 of the direct-current isolation circuit A is connected with the positive and negative signal interfaces of the piezoelectric bimorph P1, and the other end of each of the two capacitors C1 is connected with the differential positive and negative input terminals of the differential amplifier S1; one end of each of the two resistors R1 is connected with the differential positive and negative input terminals of the differential amplifier S1, and the other end is grounded; One end of each of the two capacitors C1 of the direct-current isolation circuit B is connected with the positive and negative signal interfaces of the piezoelectric bimorph P2, and the other end of each of the two capacitors C1 is connected with the differential positive and negative input terminals of the differential amplifier S2; one end of each of the two resistors R1 is connected with the differential positive and negative input terminals of the differential amplifier S2, and the other end is grounded; The left end of the resistor R2 and the left end of the resistor R3 are respectively connected with the output terminals of the differential amplifier S1 and the differential amplifier S2; the right end of the resistor R2 is connected with the negative input terminal of the precision voltage operational amplifier M; the right end of the resistor R3 is connected with the right end of the resistor R2; the positive input terminal of the precision voltage operational amplifier M is grounded; and the two ends of the resistor R4 are respectively connected between the right end of the resistor R2 and the output terminal of the precision voltage operational amplifier M. The two ends of the resistor R5 are respectively connected with the output terminal of the precision voltage operational amplifier M and the output terminal of the measuring circuit module; one end of the capacitor C2 is connected with the right end of the resistor R5, and the other end is grounded.

2. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The differential amplifier S1 and the differential amplifier S2 are of the same specification.

3. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The resistance R2, the resistance R3 and the resistance R4 are of the same specification.

4. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The upper and lower positions of the inner wall of the shell are respectively provided with mounting bosses, and the piezoelectric bimorph P1 and the piezoelectric bimorph P2 are respectively placed on the mounting bosses of the upper and lower positions of the inner wall of the shell.

5. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The piezoelectric bimorph P1 and the piezoelectric bimorph P2 are connected and fixed with the upper and lower surfaces of the center mass block through bolts.

6. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The upper piezoelectric sheet and the lower piezoelectric sheet are of the same specification.

7. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The upper top plate and the lower top plate are designed with external threads, the shell is designed with internal threads, the upper top plate and the lower top plate are connected with the shell through threads, the outer surfaces of the upper top plate and the lower top plate are designed with mounting grooves, and the upper top plate and the lower top plate are rotatably mounted through a tool.

8. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The upper top plate is matched with the upper mounting boss of the inner wall of the shell to clamp and fix the edge of the piezoelectric bimorph P1, and the lower top plate is matched with the lower mounting boss of the inner wall of the shell to clamp and fix the edge of the piezoelectric bimorph P2.

9. The temperature drift resistant high sensitivity micro-vibration sensor and its measuring circuit according to claim 1, characterized in that, The piezoelectric sheet adopts low-capacitance quartz material.

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