Modeling and design method of uniform sensitivity and low coupling three-dimensional accelerometer

Abstract

The present invention discloses a uniform sensitivity low-coupling three-dimensional accelerometer and its modeling design method, which is composed of a uniform sensitivity three-dimensional vibration pickup unit and a low-coupling three-dimensional sensing unit; the three-dimensional vibration pickup unit is a cross suspension fixed on a beryllium copper reed, the beryllium copper reed is a square formed by four equal-length frames, the four distal ends of the cross suspension are respectively located at the center positions of each frame of the beryllium copper reed, and the two straight directions of the cross suspension are respectively used as the X and Y axes; four mass blocks are fixedly arranged at the four distal positions of the cross suspension in a one-to-one correspondence, forming a three-dimensional vibration pickup module with three degrees of freedom and capable of mutual decoupling; the low-coupling three-dimensional sensing unit is used to detect the motion information of the three-dimensional vibration pickup unit relative to the accelerometer fixing seat, and realize the detection of three-dimensional acceleration based on the motion information. The present invention can realize high-precision three-dimensional micro-vibration detection, and then realize the precise suppression of three-dimensional low-frequency micro-vibration, and has strong adaptability, low cost and convenient installation and adjustment.

Description

Technical Field

[0001] The present invention relates to the field of vibration monitoring technology, and more particularly to a three-dimensional accelerometer particularly used for three-dimensional vibration detection and a modeling and design method thereof. Background Art

[0002] Precision measuring instruments, including micro-nano coordinate measuring machines, atomic force microscopes, and high-precision laser interferometers, are susceptible to external interference during operation, with microvibrations being a major factor. For example, small vibrations caused by a passing car, pedestrians, or even noise can interfere with the operation of precision instruments. Therefore, it is necessary to develop a high-precision microvibration measurement system to achieve active vibration isolation. The system must detect vibration amplitudes with a resolution of microns and be capable of real-time, high-precision measurement.

[0003] Existing 3D accelerometers include three-component and parallel types. Three-component 3D accelerometers achieve 3D vibration measurement by orthogonally mounting three one-dimensional accelerometers. This results in large coupling errors and a complex structure. Parallel 3D accelerometers achieve 3D vibration sensing using a single mechanical structure, offering high integration and a simple structure. However, existing parallel 3D accelerometers suffer from inconsistent 3D sensitivity, large coupling errors, and poor low-frequency response. To date, developing a high-precision 3D accelerometer with uniform sensitivity and low coupling remains an unresolved challenge. Summary of the Invention

[0004] In order to avoid the shortcomings of the above-mentioned existing technologies, the present invention provides a modeling and design method for a uniformly sensitive low-coupling three-dimensional accelerometer, so as to achieve high-precision three-dimensional micro-vibration detection and further achieve accurate suppression of three-dimensional low-frequency micro-vibrations, while taking into account the advantages of strong adaptability, strong modifiability, low cost and easy installation and adjustment.

[0005] The present invention adopts the following technical solutions to solve the technical problems:

[0006] The uniform sensitivity and low coupling three-dimensional accelerometer of the present invention is characterized in that it is composed of a uniform sensitivity three-dimensional vibration pickup unit and a low coupling three-dimensional sensing unit;

[0007] The three-dimensional vibration pickup unit with uniform sensitivity is composed of a cross-shaped suspension fixed on a beryllium copper reed. The beryllium copper reed is in the shape of a square formed by four equal-length frames. The geometric center of the cross-shaped suspension is co-located with the geometric center of the beryllium copper reed on the Z axis. The four distal ends of the cross-shaped suspension are located at the center positions of each frame of the beryllium copper reed, with the two straight directions of the cross-shaped suspension serving as the X axis and the Y axis respectively. Four mass blocks are fixedly arranged at the four distal ends of the cross-shaped suspension in a one-to-one correspondence, forming a three-dimensional vibration pickup module with three degrees of freedom of X-axis rotation, Y-axis rotation, and Z-axis translation, and capable of being decoupled from each other. The three-dimensional vibration pickup module is fixed to the accelerometer fixing base by bolts using through holes provided at the four corners of the beryllium copper reed.

[0008] The low-coupling three-dimensional sensing unit is used to detect the motion information of the three-dimensional vibration pickup unit relative to the accelerometer fixing base, including the translation displacement D in the Z-axis direction. Z , the rotation angle θ around the X axis X and the rotation angle θ around the Y axis Y , and realize the detection of three-dimensional acceleration based on the motion information.

[0009] The uniform sensitivity low coupling three-dimensional accelerometer of the present invention is also characterized in that the four mass blocks are all long strip components, which are fixed to the lower end surface of the cross suspension piece by screws so that the center line of the long strip components is in the Z axis.

[0010] The uniform sensitivity low-coupling three-dimensional accelerometer of the present invention is also characterized in that: in the three-dimensional sensing unit: a one-dimensional displacement sensor with low coupling characteristics is used to realize the translational displacement detection of the geometric center position of the cross suspension in the Z-axis direction; and a two-dimensional angle sensor with low coupling characteristics is used to realize the two-dimensional angle detection of the geometric center position of the cross suspension around the X-axis and around the Y-axis.

[0011] The uniform sensitivity low-coupling three-dimensional accelerometer of the present invention is also characterized in that: the one-dimensional displacement sensor is a focus error displacement sensor, an eddy current sensor, or an inductance sensor; and the two-dimensional angle sensor is a laser autocollimator, a laser interferometer, or an optical internal reflection angle sensor.

[0012] The modeling and design method of the uniform sensitivity low-coupling three-dimensional accelerometer of the present invention is characterized by being carried out in the following steps:

[0013] Step 1: Establish a 3D stiffness model:

[0014] According to the stiffness calculation method of material mechanics, based on the three-dimensional size parameters of the beryllium copper reed and the three-dimensional size parameters of the mass block, the stiffness parameters when the beryllium copper reed is fixed at the four vertices are calculated. The stiffness parameters are: Z-axis stiffness K Z, X-axis bending stiffness K θMX , X-axis torsional stiffness K θTX , Y-axis bending stiffness K θMY and Y-axis torsional stiffness K θTY ;

[0015] Establishing a three-dimensional stiffness model of the stiffness parameters with respect to the material and three-dimensional size parameters of the beryllium copper reed;

[0016] Step 2: Create a 3D motion model:

[0017] The three-dimensional motion model of the three-dimensional vibration pickup unit is established, which is the X-axis motion model represented by formula (1), the Y-axis motion model represented by formula (2), and the Z-axis motion model shown in formula (3):

[0018]

[0019]

[0020]

[0021] in:

[0022] I AX is the moment of inertia of the three-dimensional vibration pickup unit rotating around the X-axis;

[0023] I AY is the moment of inertia of the three-dimensional vibration pickup unit rotating around the Y axis;

[0024] m is the total mass of the four mass blocks;

[0025] θ X is the rotation angle of the three-dimensional vibration pickup unit around the X axis, is θ X The second derivative of

[0026] θ Y is the rotation angle of the three-dimensional vibration pickup unit around the Y axis; is θ Y The second derivative of

[0027] D Z is the translational displacement of the three-dimensional vibration pickup unit along the Z axis, D Z The second derivative of

[0028] Step 3: Create a three-dimensional resonant frequency model:

[0029] The three-dimensional resonant frequency calculation model is obtained based on the three-dimensional motion model of the three-dimensional vibration pickup unit, which are the X-axis resonant frequency calculation model represented by formula (4), the Y-axis resonant frequency calculation model represented by formula (5), and the Z-axis resonant frequency calculation model represented by formula (6):

[0030]

[0031]

[0032]

[0033] in:

[0034] f X is the X-axis resonant frequency of the three-dimensional vibration pickup unit;

[0035] f Y is the Y-axis resonance frequency of the three-dimensional vibration pickup unit;

[0036] f Z is the Z-axis resonant frequency of the three-dimensional vibration pickup unit;

[0037] Step 4: Optimize the sensitivity of the 3D vibration pickup unit:

[0038] With a X Characterize the X-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (7);

[0039] With a Y Characterize the Y-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (8);

[0040] With a Z Characterize the Z-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (9);

[0041] a X =(2πf X ) 2 ×θ X (7)

[0042] a Y =(2πf Y ) 2 ×θ Y (8)

[0043] a Z =(2πf Z ) 2 ×D Z (9)

[0044] in:

[0045] (2πf X ) 2 is the X-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0046] (2πf Y ) 2is the Y-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0047] (2πf Z ) 2 is the Z-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0048] By setting the three-dimensional size parameters of the beryllium copper reed and the three-dimensional size parameters of the mass block, f X =f Y =f Z , achieving equal sensitivity of three-dimensional vibration pickup units.

[0049] The modeling and design method of the uniform sensitivity low-coupling three-dimensional accelerometer of the present invention is also characterized in that the sensitivity is adjusted by changing the three-dimensional resonant frequency of the three-dimensional vibration pickup unit, so that the three-dimensional accelerometer obtains the set resolution and detection range, which is suitable for different application scenarios.

[0050] Compared with the existing technology, the beneficial effects of the present invention are embodied in:

[0051] 1. The present invention realizes three-dimensional micro-vibration detection. It uses a square beryllium copper reed and four mass blocks to form a symmetrical three-dimensional vibration pickup module. It can achieve three-dimensional equal sensitivity of the vibration sensing unit, and ultimately make the three-dimensional sensitivity of the accelerometer reach 10V / g. In theory, it realizes complete decoupling of three-dimensional motion and can realize accurate detection of three-dimensional low-frequency micro-vibration.

[0052] 2. The present invention adopts X and Y angle sensors with a three-dimensional coupling error of less than 2%, and a Z displacement sensor to form a three-dimensional sensing system. In combination with a symmetrical three-dimensional vibration pickup module that is completely decoupled from three-dimensional motion, the coupling error of the three-dimensional accelerometer can be kept below 2%. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a schematic diagram of the appearance of the three-dimensional accelerometer of the present invention;

[0054] Figure 2 Schematic diagram of the internal structure of the three-dimensional accelerometer of the present invention;

[0055] Figure 3 Schematic diagram of a three-dimensional vibration pickup unit of a three-dimensional accelerometer of the present invention;

[0056] Figure 4 This is an exploded schematic diagram of a three-dimensional vibration pickup unit assembly of a three-dimensional accelerometer of the present invention;

[0057] Figure 5 This is a schematic diagram of the movement of the three-dimensional vibration pickup unit in the present invention when sensing Z-direction vibration;

[0058] Figure 6Schematic diagram of the motion of the three-dimensional vibration pickup unit in the present invention when sensing X / Y direction vibration;

[0059] Figure 7 Graphs of sensitivity and coupling data for a specific implementation of the present invention.

[0060] Numbers in the figure: 1 accelerometer fixing base, 1a upper fixing base, 1b lower fixing base, 2 displacement sensor, 3 three-dimensional vibration pickup unit, 3a beryllium copper reed, 3b cross suspension plate, 3c first mass block, 3d second mass block, 3e third mass block, 3f fourth mass block, 4 two-dimensional angle sensor, 4a laser beam, 4b forty-five degree reflector. DETAILED DESCRIPTION

[0061] In this embodiment, the low-coupling three-dimensional accelerometer with uniform sensitivity is composed of a three-dimensional vibration pickup unit with uniform sensitivity and a low-coupling three-dimensional sensing unit.

[0062] See also Figure 1 and Figure 2 On the accelerometer fixing base 1, one side is composed of an upper fixing base 1a and a lower fixing base 1b forming a cylindrical body, which serves as the shell of the three-dimensional vibration pickup unit 3, and the other side is fixed with a two-dimensional angle sensor 4; the three-dimensional vibration pickup unit 3 for uniform sensitivity is fixed with a cross suspension piece 3b on the beryllium copper reed 3a. The beryllium copper reed 3a is a square formed by four equal-length frames. The geometric center of the cross suspension piece 3b is on the same Z axis as the geometric center of the beryllium copper reed 3a. The four distal ends of the cross suspension piece 3b are located at the center of each frame of the beryllium copper reed 3a. The two linear directions of the cross suspension 3b serve as the X-axis and Y-axis respectively; four mass blocks are fixedly arranged at the four distal ends of the cross suspension 3b in a one-to-one correspondence, forming a three-dimensional vibration pickup module with three degrees of freedom of X-axis rotation, Y-axis rotation, and Z-axis translation, and capable of mutual decoupling; the three-dimensional vibration pickup module is fixed to the accelerometer holder 1 by bolts using through holes arranged at the four corner positions of the beryllium copper reed 3a; the low-coupling three-dimensional sensing unit is used to detect the motion information of the three-dimensional vibration pickup unit relative to the accelerometer holder 1, including the translational displacement D in the Z-axis direction. Z , the rotation angle θ around the X axis X and the rotation angle θ around the Y axis Y , three-dimensional acceleration detection is achieved based on motion information; the three-dimensional sensing unit includes a displacement sensor 2 and a two-dimensional angle sensor 4. The displacement sensor 2 is arranged directly above the center of the cross suspension 3b and is used to detect the displacement of the cross suspension in the Z direction. The two-dimensional angle sensor 4 emits a laser beam 4a, which is reflected upward by a forty-five-degree reflector 4b and then reflected back to the two-dimensional angle sensor 4 along the original path through the lower surface of the cross suspension 3b, thereby sensing the angular motion of the cross suspension in the X and Y directions.

[0063] In specific implementation, the corresponding technical measures also include:

[0064] See also Figure 3 and Figure 4 The four mass blocks are the first mass block, the second mass block 3d, the third mass block 3e and the fourth mass block 3f. The four mass blocks are all long strip components, which are fixed on the lower end surface of the cross suspension plate 3b with screws so that the center line of the long strip component is in the Z axis.

[0065] In the three-dimensional sensing unit: a one-dimensional displacement sensor with low coupling characteristics is used, such as Figure 2 The displacement sensor 2 shown is used to detect the translational displacement of the geometric center position of the cross-suspended plate 3b in the Z-axis direction. The one-dimensional displacement sensor is a focus error displacement sensor, an eddy current sensor, or an inductive sensor. A two-dimensional angle sensor with low coupling characteristics is used to detect the two-dimensional angle of the geometric center position of the cross-suspended plate 3b around the X-axis and the Y-axis. The two-dimensional angle sensor is a laser autocollimator, a laser interferometer, or an optical internal reflection angle sensor.

[0066] The modeling and design method of the low-coupling three-dimensional accelerometer with uniform sensitivity in this embodiment is carried out in the following steps:

[0067] Step 1: Establish a 3D stiffness model:

[0068] According to the stiffness calculation method of material mechanics, based on the three-dimensional size parameters of the beryllium copper reed 3a and the three-dimensional size parameters of the mass block, the stiffness parameters of the beryllium copper reed 3a when fixed at the four vertices are calculated. The stiffness parameters are: Z-axis stiffness K Z , X-axis bending stiffness K θMX , X-axis torsional stiffness K θTX , Y-axis bending stiffness K θMY and Y-axis torsional stiffness K θTY ; Establish a three-dimensional stiffness model with stiffness parameters regarding the material and three-dimensional size parameters of the beryllium copper reed 3a.

[0069] Step 2: Create a 3D motion model:

[0070] The three-dimensional motion model of the three-dimensional vibration pickup unit is established, which is the X-axis motion model represented by formula (1), the Y-axis motion model represented by formula (2), and the Z-axis motion model shown in formula (3):

[0071]

[0072]

[0073]

[0074] in:

[0075] I AX is the moment of inertia of the three-dimensional vibration pickup unit rotating around the X-axis;

[0076] I AY is the moment of inertia of the three-dimensional vibration pickup unit rotating around the Y axis;

[0077] m is the total mass of the four mass blocks;

[0078] θ X is the rotation angle of the three-dimensional vibration pickup unit around the X axis, is θ X The second derivative of

[0079] θ Y is the rotation angle of the three-dimensional vibration pickup unit around the Y axis; is θ Y The second derivative of

[0080] D Z is the translational displacement of the three-dimensional vibration pickup unit along the Z axis, D Z The second derivative of

[0081] Step 3: Create a three-dimensional resonant frequency model:

[0082] The three-dimensional resonant frequency calculation model is obtained based on the three-dimensional motion model of the three-dimensional vibration pickup unit, which are the X-axis resonant frequency calculation model represented by formula (4), the Y-axis resonant frequency calculation model represented by formula (5), and the Z-axis resonant frequency calculation model represented by formula (6):

[0083]

[0084]

[0085]

[0086] in:

[0087] f X is the X-axis resonant frequency of the three-dimensional vibration pickup unit;

[0088] f Y is the Y-axis resonance frequency of the three-dimensional vibration pickup unit;

[0089] f Z is the Z-axis resonant frequency of the three-dimensional vibration pickup unit;

[0090] Step 4: Optimize the sensitivity of the 3D vibration pickup unit:

[0091] With a XCharacterize the X-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (7);

[0092] With a Y Characterize the Y-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (8);

[0093] With a Z Characterize the Z-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (9);

[0094] a X =(2πf X ) 2 ×θ X (7)

[0095] a Y =(2πf Y ) 2 ×θ Y (8)

[0096] a Z =(2πf Z ) 2 ×D Z (9)

[0097] in:

[0098] (2πf X ) 2 is the X-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0099] (2πf Y ) 2 is the Y-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0100] (2πf Z ) 2 is the Z-axis mechanical sensitivity of the three-dimensional vibration pickup unit;

[0101] By setting the three-dimensional size parameters of the beryllium copper reed and the three-dimensional size parameters of the mass block, f X =f Y =f Z , achieving equal sensitivity of three-dimensional vibration pickup units.

[0102] By changing the three-dimensional resonant frequency of the three-dimensional vibration pickup unit to achieve sensitivity adjustment, the three-dimensional accelerometer can obtain the set resolution and detection range, which is suitable for different application scenarios.

[0103] like Figure 5 The diagram shows the movement of the three-dimensional vibration pickup unit 3 when it is excited by vibration in the Z direction. The cross suspension piece 3b moves upward, the beryllium copper reed 3a bends upward, and the three-dimensional vibration pickup unit 3 has four mass blocks 3c. The whole structure moves upward.Z , no angular motion around the X-axis or Y-axis is generated, effectively reducing the coupling error of the three-dimensional accelerometer.

[0104] like Figure 6 The figure shows the motion of the three-dimensional vibration pickup unit when it is excited by vibration in the X direction. The cross suspension 3b rotates around the Y axis, the two sides of the beryllium copper reed 3a parallel to the Y axis bend, and the two sides of the beryllium copper reed 3a parallel to the X axis twist around the Y axis. The entire three-dimensional vibration pickup unit 3 rotates θ around the Y axis when it is excited by vibration in the X direction. X , no Z-direction movement is generated, effectively reducing the coupling error of the three-dimensional accelerometer.

[0105] like Figure 7 The figure shows the test data of the three-dimensional sensitivity and coupling characteristics of the three-dimensional accelerometer. Figure 7 Figure (a) shows the three-dimensional output characteristics of the three-dimensional accelerometer when vibration excitation is applied only in the X direction. Figure 7 Figure (b) shows the three-dimensional output characteristics of the three-dimensional accelerometer when vibration excitation is applied only in the Y direction. Figure 7 Figure (c) shows the three-dimensional output characteristics of the three-dimensional accelerometer when vibration excitation is applied only in the X direction. The four-quadrant photodetector model used in the selected two-dimensional angle sensor is: SPOT-4D (OSI Optoelectronics Co.), with a photosensitive surface of 4*4mm 2 The displacement sensor model used is E401 (Anhui Jianxing Technology); the beryllium copper reed has a side length of 34mm, a width of 2mm per side, and a thickness of 0.15mm; the mass has a height of 18mm, a length of 15mm, and a width of 4mm. Under these conditions, the performance parameters achieved by the present invention are shown in Table 1.

[0106] Table 1

[0107]

[0108] As shown in Table 1, the coupling error of the three-dimensional accelerometer is below 2%, and the three-dimensional sensitivity is above 10V / g.

Claims

1. A uniform sensitivity low coupling three-dimensional accelerometer, characterized by It consists of a three-dimensional vibration pickup unit with uniform sensitivity and a three-dimensional sensing unit with low coupling; The three-dimensional vibration pickup unit with uniform sensitivity is a cross suspension piece (3b) fixedly arranged on a beryllium copper reed (3a); the beryllium copper reed (3a) is in a square shape formed by four equal-length frames; the geometric center of the cross suspension piece (3b) and the geometric center of the beryllium copper reed (3a) are both located on the Z axis; the four distal ends of the cross suspension piece (3b) are located at the center positions of the respective frames of the beryllium copper reed (3a); the two linear directions of the cross suspension piece (3b) are respectively used as the X axis and the Y axis; four mass blocks are fixedly arranged at the four distal ends of the cross suspension piece (3b) in a one-to-one correspondence, forming a three-dimensional vibration pickup module with three degrees of freedom of X-axis rotation, Y-axis rotation and Z-axis translation, and capable of mutual decoupling; The three-dimensional vibration pickup module utilizes through holes provided at four corner positions of the beryllium copper reed (3a) and is fixed on the accelerometer fixing seat (1) by bolts; The low-coupling three-dimensional sensing unit is used to detect the motion information of the three-dimensional vibration pickup unit relative to the accelerometer fixing seat (1), including the translation displacement D in the Z-axis direction. Z , the rotation angle θ around the X axis X and the rotation angle θ around the Y axis Y , and realize the detection of three-dimensional acceleration based on the motion information.

2. The uniform sensitivity low-coupling three-dimensional accelerometer according to claim 1, characterized in that: The four mass blocks are all long strip-shaped components and are fixed on the lower end surface of the cross suspension piece (3b) by means of screws, so that the center lines of the long strip components are in the Z-axis direction.

3. The uniform sensitivity low coupling three-dimensional accelerometer according to claim 1, characterized in that: In the three-dimensional sensing unit, a one-dimensional displacement sensor with low coupling characteristics is used to detect the translational displacement of the geometric center position of the cross suspension piece (3b) in the Z-axis direction; and a two-dimensional angle sensor with low coupling characteristics is used to detect the two-dimensional angles of the geometric center position of the cross suspension piece (3b) rotating around the X-axis and around the Y-axis.

4. The uniform sensitivity low-coupling three-dimensional accelerometer according to claim 3, characterized in that: The one-dimensional displacement sensor is a focus error displacement sensor, an eddy current sensor, or an inductive sensor; the two-dimensional angle sensor is a laser autocollimator, a laser interferometer, or an optical internal reflection angle sensor.

5. A modeling and design method for a uniform sensitivity low coupling three-dimensional accelerometer according to claim 1, characterized in that Proceed as follows: Step 1: Establish a 3D stiffness model: According to the stiffness calculation method of material mechanics, based on the three-dimensional size parameters of the beryllium copper reed (3a) and the three-dimensional size parameters of the mass block, the stiffness parameters when the beryllium copper reed (3a) is fixed at four vertices are calculated, and the stiffness parameters are respectively: Z-axis stiffness K Z , X-axis bending stiffness K θMX , X-axis torsional stiffness K θTX , Y-axis bending stiffness K θMY and Y-axis torsional stiffness K θTY ; Establishing a three-dimensional stiffness model of the stiffness parameters with respect to the material and three-dimensional size parameters of the beryllium copper reed (3a); Step 2: Create a 3D motion model: The three-dimensional motion model of the three-dimensional vibration pickup unit is established, which is the X-axis motion model represented by formula (1), the Y-axis motion model represented by formula (2), and the Z-axis motion model shown in formula (3): in: I AX is the moment of inertia of the three-dimensional vibration pickup unit rotating around the X-axis; I AY is the moment of inertia of the three-dimensional vibration pickup unit rotating around the Y axis; m is the total mass of the four mass blocks; θ X is the rotation angle of the three-dimensional vibration pickup unit around the X axis, is θ X The second derivative of θ Y is the rotation angle of the three-dimensional vibration pickup unit around the Y axis; is θ Y The second derivative of D Z is the translational displacement of the three-dimensional vibration pickup unit along the Z axis, D Z The second derivative of Step 3: Create a three-dimensional resonant frequency model: The three-dimensional resonant frequency calculation model is obtained based on the three-dimensional motion model of the three-dimensional vibration pickup unit, which are the X-axis resonant frequency calculation model represented by formula (4), the Y-axis resonant frequency calculation model represented by formula (5), and the Z-axis resonant frequency calculation model represented by formula (6): in: f X is the X-axis resonant frequency of the three-dimensional vibration pickup unit; f Y is the Y-axis resonance frequency of the three-dimensional vibration pickup unit; f Z is the Z-axis resonant frequency of the three-dimensional vibration pickup unit; Step 4: Optimize the sensitivity of the 3D vibration pickup unit: With a X Characterize the X-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (7); With a Y Characterize the Y-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (8); With a Z Characterize the Z-axis excitation acceleration of the three-dimensional vibration pickup unit, and have formula (9); a X =(2πf X ) 2 ×θ X (7) a Y =(2πf Y ) 2 ×θ Y (8) a Z =(2πf Z ) 2 ×D Z (9) in: (2πf X ) 2 is the X-axis mechanical sensitivity of the three-dimensional vibration pickup unit; (2πf Y ) 2 is the Y-axis mechanical sensitivity of the three-dimensional vibration pickup unit; (2πf Z ) 2 is the Z-axis mechanical sensitivity of the three-dimensional vibration pickup unit; By setting the three-dimensional size parameters of the beryllium copper reed and the three-dimensional size parameters of the mass block, f X =f Y =f Z , achieving equal sensitivity of three-dimensional vibration pickup units.

6. The modeling and design method for a uniform sensitivity low-coupling three-dimensional accelerometer according to claim 5, characterized in that: By changing the three-dimensional resonant frequency of the three-dimensional vibration pickup unit to achieve sensitivity adjustment, the three-dimensional accelerometer can obtain the set resolution and detection range, which is suitable for different application scenarios.

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