A three-axis ultra-low frequency feed-forward measurement device based on piezoelectric sensors

Abstract

The present application relates to active vibration isolation control and sensor measurement technical field, specifically to a kind of three-axis ultra-low frequency feedforward measuring device based on piezoelectric sensor, including, buffer component is located in frame, mass block is located on buffer component, mass block two ends are equipped with connecting piece and limit block, and fixed plate is equipped on limit block, plastic column is inserted into each side wall of mass block, and plastic column penetrates connecting piece or frame, piezoelectric sensing unit is equipped on plastic column, two piezoelectric sensing units oppositely arranged are a group, the axis of two piezoelectric sensing units in same group coincides, the axis of three groups of piezoelectric sensing units is mutually orthogonal.Structure is compact, integration is high, utilize the quick response characteristics and low cross-coupling coefficient of piezoelectric material, effectively reduce the coupling interference of three-axis signal, improve the precision and timeliness of vibration signal acquisition, provide reliable sensing support for feedforward control of vibration isolation system, applied to precision instrument, aerospace and other fields of vibration isolation scene.

Description

Technical Field

[0001] This invention relates to the field of active vibration isolation control and sensor measurement technology, specifically to a triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor. Background Technology

[0002] In precision manufacturing, aerospace, and optical inspection, environmental vibration is a key factor affecting the working accuracy and stability of equipment. Vibration isolation systems, as the core devices for suppressing vibration transmission, directly determine the operational quality of precision equipment. Feedforward control technology, by implementing control in advance based on disturbance signals, effectively compensates for the lag in feedback control and has become an important means of improving the performance of vibration isolation systems. High-quality vibration measurement devices are a prerequisite for the realization of feedforward control, requiring rapid response, accurate signal transmission, and multi-dimensional data acquisition capabilities.

[0003] The vibration measurement devices used in existing vibration isolation systems are mostly single-axis sensor combinations. Triaxial vibration acquisition is achieved through the spatial arrangement of multiple single-axis sensors. This approach not only has problems such as cumbersome installation and large space occupation, but also easily leads to coupling interference of triaxial vibration signals due to installation errors and signal transmission delays between sensors, resulting in deviations between the acquired vibration information and the actual disturbance. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the vibration isolation system in the prior art is prone to coupling interference of triaxial vibration signals due to installation errors and signal transmission delays between sensors, resulting in deviation between the collected vibration information and the actual disturbance. Thus, a triaxial ultra-low frequency feedforward measurement device based on piezoelectric sensors is provided.

[0005] To address the aforementioned technical problems, this invention provides a triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor, comprising: a frame, a mass block, a connector, a limiting block, a fixing plate, a plastic column, a piezoelectric sensing unit, and a buffer assembly; the buffer assembly is disposed within the frame, the mass block is disposed on the buffer assembly, the mass block has a connector and a limiting block at both ends, and a fixing plate is disposed on the limiting block; the plastic column is inserted into each side wall of the mass block, and the plastic column penetrates the connector or the frame; a piezoelectric sensing unit is disposed on the plastic column, two piezoelectric sensing units arranged opposite each other form a group, the axes of the two piezoelectric sensing units in the same group coincide, and the axes of the three groups of piezoelectric sensing units are orthogonal to each other.

[0006] Furthermore, a gap is provided between the two plastic pillars located at both ends of the mass block.

[0007] Furthermore, the piezoelectric sensing unit includes a housing, a piezoelectric sheet, and a rubber ring. The piezoelectric sheet is disposed inside the housing, and the rubber ring is located between the housing and the piezoelectric sheet.

[0008] Furthermore, the limiting block has a ring-shaped structure, and the connecting member is disposed on the mass block and located inside the limiting block.

[0009] Furthermore, the frame includes an upper end cover, a side wall ring plate, and a lower end cover. The upper end cover and the lower end cover are located at both ends of the side wall ring plate, and the buffer assembly is disposed on the lower end cover.

[0010] Furthermore, the upper and lower end covers are provided with mounting grooves, wiring grooves, and sensing unit through holes. The mounting grooves are used to install the pressure sensing unit, the wiring grooves are used to prevent the wires of the pressure sensing unit from passing through, and the sensing unit through holes are used for the wires to pass through.

[0011] Furthermore, the upper and lower end covers are provided with device fixing holes and limiting threaded holes. The locking member passes through the device fixing hole and is connected to the base, and the locking member passes through the limiting threaded hole and is connected to the limiting block.

[0012] Furthermore, the buffer assembly includes a plurality of rubber pads, which are disposed within the pad mounting holes of the lower end cover.

[0013] Furthermore, the side wall ring plate is provided with a sensor unit fixing hole and a through hole. The sensor unit fixing hole is adapted to pass through the locking member and connect with the piezoelectric sensor unit, and the through hole is adapted to accommodate the plastic column.

[0014] Furthermore, the fixing plate has a set screw adjustment hole in the middle to facilitate the adjustment and removal of the set screw on the mass block.

[0015] The technical solution of this invention has the following advantages: This triaxial ultra-low frequency feedforward measurement device based on piezoelectric sensors features an integrated structure, precise signal acquisition, and rapid response. Through optimized structural design, it improves the transmission speed and acquisition accuracy of vibration signals, providing reliable support for feedforward control of vibration isolation systems. Utilizing the positive piezoelectric effect and low cross-coupling coefficient of piezoelectric materials, it achieves efficient and accurate acquisition of three-dimensional vibration signals.

[0016] When vibration occurs, the mass block, under the action of inertia, passes through the plastic column and accurately transmits the vibration load to the piezoelectric sensing unit in the corresponding direction. The piezoelectric sensing unit converts the mechanical vibration signal into an electrical signal output, realizing the synchronous and real-time acquisition of vibration signals in three-dimensional space.

[0017] This device features a compact structure and high integration. By utilizing the fast response characteristics and low cross-coupling coefficient of piezoelectric materials, it effectively reduces the coupling interference of triaxial signals, improves the accuracy and timeliness of vibration signal acquisition, and provides reliable sensing support for the feedforward control of vibration isolation systems. It can be widely used in vibration isolation scenarios in fields such as precision instruments and aerospace.

[0018] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0019] 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.

[0020] Figure 1 A perspective view of a triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor; Figure 2 for Figure 1 A 3D view with the top cover removed; Figure 3 This is a schematic diagram of the internal structure of a triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor. Figure 4 This is an exploded view; Figure 5 This is a cross-sectional view of the overall structure of a triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor. Figure 6 This is a schematic diagram of the end cap structure; Figure 7 This is a schematic diagram of the side wall ring plate structure; Figure 8 This is a schematic diagram of the overall structure of the piezoelectric sensing unit; Figure 9 This is a cross-sectional view of the overall structure of the piezoelectric sensing unit; Figure 10 This is a schematic diagram of the mass block structure; Figure 11 This is a schematic diagram of the fixed plate structure; Figure 12 This is a schematic diagram of a performance testing platform for a three-axis ultra-low frequency feedforward measurement device. Figure 13 A comparison diagram of the amplitude-frequency characteristics of vibration signals in the X-axis direction; Figure 14This is a graph showing the relative error of the vibration signal amplitude in the X-axis direction. Figure 15 A comparison chart of the amplitude-frequency characteristics of vibration signals in the Y-axis direction; Figure 16 This is a graph showing the relative error of the vibration signal amplitude in the Y-axis direction. Figure 17 A comparison diagram of the amplitude-frequency characteristics of vibration signals in the Z-axis direction; Figure 18 This is a graph showing the relative error of the vibration signal amplitude in the Z-axis direction.

[0021] Explanation of reference numerals in the attached figures: 1. Frame; 2. Mass block; 3. Connector; 4. Limiting block; 5. Fixing plate; 6. Plastic column; 7. Piezoelectric sensing unit; 8. Housing; 9. Piezoelectric sheet; 10. Rubber ring; 11. Top cover; 12. Side wall ring plate; 13. Bottom cover; 14. Mounting groove; 15. Wiring groove; 16. Sensing unit through hole; 17. Device fixing hole; 18. Limiting threaded hole; 19. Rubber gasket; 20. Gasket mounting hole; 21. Transmission... 21. Sensor unit positioning hole; 22. Sensor unit fixing hole; 23. Through hole; 24. Set screw adjustment hole; 25. End cap mounting hole; 26. End cap mounting through hole; 27. Wire through hole; 28. Piezoelectric threaded hole; 29. ​​Piezoelectric wire through hole; 30. Piezoelectric plate fixing hole; 31. Plastic mounting hole; 32. Connector mounting hole; 33. Mass threaded hole; 34. Plastic threaded hole; 35. Fixing through hole; 36. Sensor unit mounting hole. Detailed Implementation

[0022] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are to be considered exemplary in nature and not restrictive.

[0023] The preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0024] Please see Figures 1 to 18As shown, the present invention provides a triaxial ultra-low frequency feedforward measurement device based on piezoelectric sensors, comprising: a frame 1, a mass block 2, a connector 3, a limiting block 4, a fixing plate 5, a plastic column 6, a piezoelectric sensing unit 7, and a buffer assembly; the buffer assembly is disposed within the frame 1, the mass block 2 is disposed on the buffer assembly, the mass block 2 is provided with a connector 3 and a limiting block 4 at both ends, and a fixing plate 5 is provided on the limiting block 4; the plastic column 6 is inserted into each side wall of the mass block 2, and the plastic column 6 penetrates the connector 3 or the frame 1; the piezoelectric sensing unit 7 is provided on the plastic column 6, two piezoelectric sensing units 7 arranged opposite each other form a group, the axes of the two piezoelectric sensing units 7 in the same group coincide, and the axes of the three groups of piezoelectric sensing units 7 are orthogonal to each other.

[0025] A buffer assembly is located at the bottom of mass block 2 to support it. Connectors 3 and limiting blocks 4 are located at both the top and bottom of mass block 2. Two fixing plates 5 are symmetrically placed on the top two sides of mass block 2, and are connected from top to bottom in the following order using bolts and nuts: fixing plates 5, mass block 2, buffer assembly, and lower end cover 13, ensuring the stability of mass block 2 installation. Piezoelectric sensing units 7 are installed on all six end faces of mass block 2. These units are connected to mass block 2 via plastic pillars 6. Specifically, the piezoelectric sensing units 7 located at the top and bottom of mass block 2 are within the frame 1, with one end of each plastic pillar 6 inserted into mass block 2 and the other end passing through the connectors 3 mounted on mass block 2 to contact the piezoelectric sensing units 7. The four piezoelectric sensing units 7 located around mass block 2 are outside the frame 1, with one end of each plastic pillar 6 inserted into mass block 2 and the other end extending out of the side wall ring plate 12 to contact the piezoelectric sensing units 7 mounted outside the side wall ring plate 12. Two piezoelectric sensing units 7 arranged opposite each other form a group. The axes of the two piezoelectric sensing units 7 in the same group coincide, and the axes of the three groups of piezoelectric sensing units 7 are orthogonal to each other.

[0026] This triaxial ultra-low frequency feedforward measurement device based on piezoelectric sensors features an integrated structure, precise signal acquisition, and rapid response. Through optimized structural design, it improves the transmission speed and acquisition accuracy of vibration signals, providing reliable support for feedforward control of vibration isolation systems. Utilizing the positive piezoelectric effect and low cross-coupling coefficient of piezoelectric materials, it achieves efficient and accurate acquisition of three-dimensional vibration signals.

[0027] When vibration occurs, the mass block 2, under the action of inertia, transmits the vibration load precisely to the piezoelectric sensing unit 7 in the corresponding direction through the plastic column 6. The piezoelectric sensing unit 7 converts the mechanical vibration signal into an electrical signal output, realizing the synchronous and real-time acquisition of vibration signals in three-dimensional space.

[0028] This device features a compact structure and high integration. By utilizing the fast response characteristics and low cross-coupling coefficient of piezoelectric materials, it effectively reduces the coupling interference of triaxial signals, improves the accuracy and timeliness of vibration signal acquisition, and provides reliable sensing support for the feedforward control of vibration isolation systems. It can be widely used in vibration isolation scenarios in fields such as precision instruments and aerospace.

[0029] In some optional embodiments, the piezoelectric sensing unit 7 includes a housing 8, a piezoelectric sheet 9, and a rubber ring 10, wherein the piezoelectric sheet 9 is disposed inside the housing 8, and the rubber ring 10 is located between the housing 8 and the piezoelectric sheet 9.

[0030] Three piezoelectric plate fixing holes 30 are evenly distributed inside the outer casing 8. The piezoelectric plate fixing holes 30 are used to install studs to clamp the piezoelectric plate 9. A rubber ring 10 is placed between the piezoelectric plate 9 and the outer casing 8. The rubber ring 10 plays a buffering role to prevent rigid contact from causing damage to the piezoelectric plate 9 during operation.

[0031] Two piezoelectric wire holes 29 are distributed on the side of the housing 8 to allow wires connected to the piezoelectric plate 9 to pass through. Two piezoelectric threaded holes 28 are distributed along the axis of symmetry of the piezoelectric sensing unit 7 for installing terminals and facilitating wire connection. Four sensing unit positioning holes 21 are located around the perimeter of the housing 8, and studs pass through the sensing unit positioning holes 21 to achieve fixed installation of the piezoelectric sensing unit 7.

[0032] The limiting block 4 is a ring structure, and the connecting member 3 is disposed on the mass block 2 and located inside the limiting block 4.

[0033] Specifically, the frame 1 includes an upper end cover 11, a side wall ring plate 12, and a lower end cover 13. The upper end cover 11 and the lower end cover 13 are located at both ends of the side wall ring plate 12, and the buffer assembly is disposed on the lower end cover 13. The buffer assembly includes a plurality of rubber pads 19, which are disposed in the pad mounting holes 20 of the lower end cover 13.

[0034] There are four rubber gaskets 19, which are symmetrically arranged in the gasket mounting holes 20 of the lower end cover 13, and play the role of supporting the mass block 2.

[0035] Each of the four sides of the side wall ring plate 12 has an end cap mounting through hole 26 at the top and bottom, which cooperates with the end cap mounting holes 25 on the upper end cap 11 and the lower end cap 13 for connection between the two.

[0036] One side of the side wall ring plate 12 has a wire through hole 27 for connecting the wires of the sensing unit installed on the lower end cover 13.

[0037] In some optional embodiments, the upper end cover 11 and the lower end cover 13 are provided with a mounting groove 14, a wiring groove 15, and a sensing unit through hole 16. The mounting groove 14 is used to install the pressure sensing unit, the wiring groove 15 is used to prevent the wires of the pressure sensing unit from passing through, and the sensing unit through hole 16 is used for the wires to pass through.

[0038] The mounting groove 14 on the inner center of the upper end cover 11 and the lower end cover 13 is used to place the piezoelectric sensing unit 7. Four sensing unit mounting holes 36 are distributed around the inside of the mounting groove 14, through which the piezoelectric sensing unit 7 can be fixed on the upper end cover 11 and the lower end cover 13.

[0039] A wiring groove 15 is opened on one side of the mounting groove 14. The wiring groove 15 is used to place wires. A sensing unit through hole 16 is provided in the wiring groove 15 to facilitate the wires to pass through.

[0040] In some optional embodiments, the upper end cover 11 and the lower end cover 13 are provided with device fixing holes 17 and limiting threaded holes 18. The locking member passes through the device fixing holes 17 and is connected to the base, that is, the triaxial ultra-low frequency feedforward measurement device based on piezoelectric sensor is fixed on the base.

[0041] The side wall ring plate 12 is provided with a sensor unit fixing hole 22 and a through hole 23. The sensor unit fixing hole 22 is adapted to pass through the locking member and connect to the piezoelectric sensor unit 7, and the through hole 23 is adapted to accommodate the plastic column 6.

[0042] There are 4×4 sensing unit fixing holes 22 around the side wall ring plate 12 for fixing and installing the piezoelectric sensing unit 7 on the side wall ring plate 12.

[0043] The side wall ring plate 12 has four through holes 23 at the center of its four sides. The through holes 23 allow the plastic column 6 to pass through and connect the mass block 2 located inside the ring plate and the piezoelectric sensing unit 7 installed on the outside.

[0044] Mass block 2 has a cuboid structure, and each of its six sides has a plastic mounting hole 31 at its center. The plastic mounting holes 31 are used to place the plastic pillars 6. Four plastic threaded holes 34 are used to install set screws to fix the four plastic pillars 6 on the sides.

[0045] Mass block 2 has threaded holes 33 at its four corners for installing rubber gaskets 19. Bolts pass through the fixing through hole 35 of the fixing plate 5, the threaded holes 33, the rubber gaskets 19, and the gasket mounting holes 20 of the lower end cover 13 in sequence from top to bottom, and are connected to each component with nuts. There are two connector mounting holes 32 next to the holes of the plastic pillars 6 on the upper and lower sides of mass block 2 for installing connectors 3.

[0046] The middle part of the fixing plate 5 has a set screw adjustment hole 24 to facilitate the adjustment and installation / removal of the set screw on the mass block 2.

[0047] The internal mass block 2 acts as an inertial body. Plastic pillars 6 extend from the center of each face of the mass block 2, with the ends of the pillars pre-tightly pressing against the piezoelectric plates 9 of the corresponding piezoelectric sensing units 7. When a force is applied to the base on which the device is mounted, the frame 1 moves with the base, while the mass block 2, due to its own inertia, lags behind the movement of the frame 1, resulting in a relative displacement between them. The plastic pillars 6 then convert this displacement into a pressure change applied to the piezoelectric plate 9. Based on the positive piezoelectric effect, the piezoelectric plate 9 converts the pressure change into a proportional charge signal output. Limiting blocks 4 on the upper end cover 11 and the lower end cover 13 act as vertical limiters to prevent large displacement of the mass block 2 from damaging the piezoelectric plate 9 when the device is impacted. Two fixing plates 5 on the mass block 2 act as horizontal limiters.

[0048] Regarding the output signal, the three sets of piezoelectric sensing units 7 respectively realize vibration measurement in three orthogonal directions in space. Furthermore, two piezoelectric sensing units 7 in the same group form a differential signal output, which can improve the sensitivity of each axis measurement and effectively suppress common-mode interference and inter-axis cross-coupling. The output signals of all piezoelectric sensing units 7 are led to an external conditioning circuit, and after signal processing, a high-precision triaxial vibration acceleration electrical signal is restored. This signal can be directly used as the reference input of the feedforward controller to drive the actuator to generate a counteracting force, achieving active vibration isolation.

[0049] To test the vibration measurement performance of the device of the present invention, a vibration test experiment was set up in this example, as shown in the attached figure. Figure 12 As shown. The device is placed on a vibration table, which can apply vibrations in the Z-axis, horizontal X-axis, and Y-axis directions corresponding to the measurement direction of the device. Furthermore, a Polytec VibroFlex single-point laser vibrometer is used to measure the actual vibration in each of the three directions of the vibration table. The triaxial vibration table sequentially generates sweep frequency vibration signals from 0.1Hz to 100Hz in the three directions. Figures 13 to 17 This refers to the spectrum of the vibration signal measured by this device and the laser vibration meter, as well as the relative error between the two.

[0050] As attached Figure 13 , 15 Figures 1 and 17 show a comparison of the amplitude-frequency characteristics of vibration signals measured by a triaxial ultra-low frequency feedforward measuring device and a laser vibrometer in the X, Y, and Z directions, respectively. Figure 14 , 16Figures 1 and 18 show the relative amplitude errors of the triaxial ultra-low frequency feedforward measurement device and the laser vibrometer in three directions, respectively. It can be seen that in the 0.1Hz-100Hz range, the spectral trends of the triaxial ultra-low frequency feedforward measurement device and the laser vibrometer are basically consistent, with small amplitude differences. The relative error between the two is within 8%, and less than 5% in the low-frequency range of 0.1Hz-10Hz. This indicates that the measurement results of this device are in good agreement with the reference device, the laser vibrometer. These results prove that this device, utilizing a piezoelectric sensor and its integrated structural design, can accurately acquire three-dimensional vibration signals, meeting the measurement requirements of feedforward control in vibration isolation systems.

[0051] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor, characterized in that, include: The frame (1), mass block (2), connector (3), limiting block (4), fixing plate (5), plastic column (6), piezoelectric sensing unit (7), and buffer assembly are provided. The buffer assembly is located inside the frame (1), the mass block (2) is located on the buffer assembly, the two ends of the mass block (2) are provided with connector (3) and limiting block (4), and the limiting block (4) is provided with fixing plate (5). The plastic column (6) is inserted into each side wall of the mass block (2), and the plastic column (6) passes through the connector (3) or the frame (1). The plastic column (6) is provided with piezoelectric sensing unit (7). Two piezoelectric sensing units (7) arranged opposite each other are a group. The axes of the two piezoelectric sensing units (7) in the same group coincide. The axes of the three groups of piezoelectric sensing units (7) are orthogonal to each other.

2. The triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 1, characterized in that, A gap is provided between the two plastic pillars (6) located at both ends of the mass block (2).

3. The triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 1, characterized in that, The piezoelectric sensing unit (7) includes a housing (8), a piezoelectric sheet (9), and a rubber ring (10). The piezoelectric sheet (9) is located inside the housing (8), and the rubber ring (10) is located between the housing (8) and the piezoelectric sheet (9).

4. The triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 1, characterized in that, The limiting block (4) is a ring structure, and the connecting member (3) is disposed on the mass block (2) and located inside the limiting block (4).

5. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to any one of claims 1-4, characterized in that, The frame (1) includes an upper end cover (11), a side wall ring plate (12), and a lower end cover (13). The upper end cover (11) and the lower end cover (13) are located at both ends of the side wall ring plate (12), and the buffer assembly is disposed on the lower end cover (13).

6. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 5, characterized in that, The upper end cover (11) and the lower end cover (13) are provided with mounting groove (14), wiring groove (15), and sensing unit through hole (16). The mounting groove (14) is used to install the pressure sensing unit, the wiring groove (15) is used to prevent the wires of the pressure sensing unit from passing through, and the sensing unit through hole (16) is used for the wires to pass through.

7. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 6, characterized in that, The upper end cover (11) and the lower end cover (13) are provided with a device fixing hole (17) and a limiting threaded hole (18). The locking member passes through the device fixing hole (17) and is connected to the base. The locking member passes through the limiting threaded hole (18) and is connected to the limiting block (4).

8. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 7, characterized in that, The buffer assembly includes a plurality of rubber pads (19), which are disposed in the pad mounting holes (20) of the lower end cap (13).

9. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 8, characterized in that, The side wall ring plate (12) is provided with a sensor unit fixing hole (22) and a through hole (23). The sensor unit fixing hole (22) is adapted to pass through the locking member and connect to the piezoelectric sensor unit (7). The through hole (23) is adapted to accommodate the plastic column (6).

10. A triaxial ultra-low frequency feedforward measurement device based on a piezoelectric sensor according to claim 1, characterized in that, The fixing plate (5) has a set screw adjustment hole (24) in the middle so as to adjust and remove the set screw on the mass block (2).

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