CN213875733U

CN213875733U - Triaxial piezoresistive accelerometer

Info

Publication number: CN213875733U
Application number: CN202020943328.8U
Authority: CN
Inventors: 维尼特·辛格; 内丘克武克里斯·韦金亚; 陈林峰; 潘峰
Original assignee: Huzhou Jiuding Electronic Co Ltd
Current assignee: Huzhou Jiuding Electronic Co Ltd
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2021-08-03
Anticipated expiration: 2030-05-29

Abstract

The utility model provides a triaxial piezoresistive accelerometer, includes support frame, quality piece to and elastic cantilever beam, the quality piece passes through elastic cantilever beam hang in support frame's central point puts, is located support frame with between the quality piece elastic cantilever beam goes up the symmetric distribution and has the varistor who meets an emergency that a plurality of resistances equal, four interior angles of support frame are equipped with spacing module respectively, spacing module and adjacent elastic cantilever beam with be formed with X to and Y to the anti clearance of transshipping between the quality piece, the upper and lower both sides of support frame are equipped with upper cover plate and upper cover plate respectively, the quality piece with lower apron and be formed with Z to the anti clearance of transshipping between the upper cover plate. The utility model discloses have higher sensitivity, accuracy, rigidity, help the piece to reset, reduced systematic error, improved measurement accuracy, reduced the interaxial coupling of accelerometer.

Description

Triaxial piezoresistive accelerometer

Technical Field

The utility model relates to a sensor technical field, especially a triaxial piezoresistive accelerometer.

Background

As an inertial device, the accelerometer is widely applied to the fields of aerospace, transportation, automatic control, biology, chemistry, medical analysis, vibration test and the like. With the development and popularization of industry 4.0, the accelerometer is developing towards miniaturization, integration, high reliability and high sensitivity. Accelerometers currently have many types, including piezoresistive, piezoelectric, capacitive, tunnel, etc. The piezoresistive accelerometer has the advantages of small size, high sensitivity, good stability, good dynamic response characteristic and output, wide frequency range, low batch production cost, good compatibility with a silicon integrated circuit planar process and the like, and is widely favored.

Most of the single accelerometers on the market can only detect the acceleration in one or two axial directions, and can not detect the acceleration in three axial directions. However, many applications require a three-axis accelerometer to detect acceleration vectors. There are three methods for implementing piezoresistive three-axis micro-acceleration sensor. The first method is to assemble three single-axis piezoresistive accelerometers together to realize the function of three-axis measurement. However, the method has the disadvantages of large volume, difficult assembly and low vector measurement precision. The second method is to fabricate three uniaxial piezoresistive acceleration sensors on the same chip at the same time. This approach increases the complexity of the process and the cost of the process. And the third method is that the same mass block is utilized to sense acceleration signals in three directions, when the mass block senses accelerations in different directions, the resistance values of the resistors at different positions can be changed, so that the output voltage of a Wheatstone bridge formed by the resistors is changed, and the magnitude and the direction of the acceleration are detected. The micro-accelerometer of the third processing technology has the advantages of small volume, light weight, low cost, low power consumption and the like. In recent years, three-axis piezoresistive micro-accelerometers have been rapidly developed.

However, the current triaxial accelerometer still has the problems of low sensitivity, large coupling between axes, complex packaging structure and low yield caused by complex processing technology.

Disclosure of Invention

The utility model aims at providing a triaxial piezoresistive accelerometer, the utility model provides a current triaxial accelerometer sensitivity low, the coupling is big between the axle, and packaging structure is complicated to and because the low problem of yield that complicated processing technology arouses.

The technical solution of the utility model is that: a triaxial piezoresistive accelerometer comprises a supporting frame, a mass block and an elastic cantilever beam, wherein the mass block is suspended at the central position of the supporting frame through the elastic cantilever beam, a plurality of strain piezoresistors with equal resistance values are symmetrically distributed on the elastic cantilever beam between the supporting frame and the mass block, limit modules are respectively arranged at four inner corners of the supporting frame, X-direction and Y-direction overload-resistant gaps are formed between the limit modules and the adjacent elastic cantilever beam and the mass block, a lower cover plate and an upper cover plate are respectively arranged at the upper side and the lower side of the supporting frame, Z-direction overload-resistant gaps are formed between the mass block and the lower cover plate as well as between the mass block and the upper cover plate, and the elastic cantilever beam comprises a single-end part, a double-end part and a middle part for connecting the single-end part and the double-end part, the single-end part is connected with the supporting frame, and the double-end part is connected with the mass block.

Preferably, the number of the elastic cantilever beams is four, and six strain piezoresistors are arranged on each elastic cantilever beam.

Preferably, a plurality of metal pads are distributed on the supporting frame, the metal pads are symmetrically and uniformly distributed along the axis of the supporting frame, and the metal pads on each edge of the supporting frame are electrically connected with the strain piezoresistors on the adjacent elastic cantilever beams in a one-to-one correspondence mode through metal leads.

Preferably, the number of the metal pads on the supporting frame is twenty-four, and each side of the supporting frame is provided with six metal pads.

Preferably, the mass block has a centrosymmetric shape.

Preferably, the mass has a square shape.

The utility model has the advantages that:

compared with the prior art, the utility model discloses higher sensitivity and accuracy have. In addition, the compound cantilever beam adopted by the embodiment has better rigidity compared with the common elastic cantilever beam at present, is favorable for resetting the mass block, reduces the system error and improves the measurement precision. Furthermore, the shear stress in the Y-axis (X-axis) direction caused by the acceleration component of the X-axis (Y-axis) is mainly concentrated in the middle part of the compound cantilever beam, the influence of the shear stress on the strain piezoresistors positioned at the single-end part and the double-end part of the compound cantilever beam is reduced, and the inter-axis coupling of the accelerometer is reduced.

Drawings

Fig. 1 is a schematic structural diagram of a three-axis piezoresistive accelerometer according to an embodiment of the present invention;

FIG. 2 is a longitudinal cross-sectional view of the present invention;

FIG. 3 is a schematic view of the elastic cantilever;

FIG. 4 is a wiring diagram of the strain varistor of FIG. 3;

fig. 5 is a wheatstone bridge diagram for detecting X-axis direction signals formed by connecting strain sensitive resistors according to an embodiment of the present invention;

fig. 6 is a wheatstone bridge diagram for detecting Y-axis direction signals formed by connecting the strain sensitive resistors according to the embodiment of the present invention;

fig. 7 is a wheatstone bridge diagram for detecting Z-axis direction signals formed by connecting strain sensitive resistors according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of another triaxial piezoresistive accelerometer according to an embodiment of the present invention;

fig. 9 is a partially enlarged view of fig. 8.

In the figure: the device comprises a supporting frame 1, a mass block 2, an elastic cantilever beam 3-1 in the negative direction of an X axis, an elastic cantilever beam 3-2 in the positive direction of the X axis, an elastic cantilever beam 3-3 in the negative direction of a Y axis, an elastic cantilever beam 3-4 in the positive direction of the Y axis, a limiting module 4, a lower cover plate 5, an upper cover plate 6, strain piezoresistors R1-R24, a metal pad 7 and a metal lead 8.

Detailed Description

The present invention will be further described with reference to the following embodiments in conjunction with the accompanying drawings.

Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that: unless specifically stated otherwise, the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention.

The following description of the exemplary embodiment(s) is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. In all examples shown and discussed, any particular value should be construed as merely illustrative and not limiting. Thus, other examples of the exemplary embodiments may have different values.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

In order to solve the technical problem, the utility model provides a triaxial piezoresistive accelerometer. With respect to embodiments of the present invention, a three-axis piezoresistive accelerometer will be described in detail below.

Fig. 1 is a schematic structural diagram of a three-axis piezoresistive accelerometer according to an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line A-A' of FIG. 1; FIG. 3 is an enlarged view of a portion of FIG. 1; fig. 4 is a wiring diagram of the strain varistor of fig. 3.

Referring to fig. 1 to 4, a three-axis piezoresistive accelerometer includes a supporting frame l, a mass block 2, and elastic cantilevers 3, wherein the mass block 2 is suspended at a central position of the supporting frame l by the elastic cantilevers 3, the mass block 2 is fixed to the supporting frame l by the elastic cantilevers 3 in two directions perpendicular to each other (X axis and Y axis), respectively, a lower surface of the supporting frame l exceeds a lower surface of the mass block 2, a plurality of strain piezoresistors Rl-R24 with equal resistance values are symmetrically distributed on the elastic cantilevers 3 between the supporting frame l and the mass block 2, preferably, the number of the strain piezoresistors is 24, which are respectively marked as Rl-R24, the number of the elastic cantilevers 3 is four, six strain piezoresistors are arranged on each elastic cantilever 3, a plurality of metal pads 7 are distributed on the supporting frame 1, and the metal pads 7 are symmetrically and uniformly distributed along an axis of the supporting frame 1, support metal pad 7 on every edge on the frame 1 and adjacent elastic cantilever beam 3 on the varistor strain passes through metal lead 8 one-to-one and is connected, it is preferred, the quantity of the metal pad 7 on the support frame 1 is twenty four, and every limit that supports frame 1 is equipped with six metal pads 7, four interior angles of support frame 1 are equipped with spacing module 4 respectively, be formed with X between spacing module 4 and adjacent elastic cantilever beam 3 and the quality piece 2 to and Y to anti-overload clearance, the upper and lower both sides of supporting frame 1 are equipped with apron 5 and upper cover plate 6 down respectively, be formed with Z to anti-overload clearance between quality piece 2 and apron 5 and the upper cover plate 6 down.

It should be noted that the shape of the mass block 2 is a central symmetrical shape, and the shape of the mass block 2 of this embodiment is a square, and in other embodiments of the present invention, the shape of the mass block 2 may be other central symmetrical shapes, such as an octagon and a circle.

As shown in fig. 1, 3 and 4, the elastic cantilever beam 3 is a compound cantilever beam, the elastic cantilever beam 3 includes a single-end portion 301, a double-end portion 302, and an intermediate portion 303 connecting the single-end portion 301 and the double-end portion 302, in this embodiment, the single-end portion 301 is connected to the support frame 1, the double-end portion 302 is connected to the mass block 2, six strain piezoresistors are respectively disposed on the elastic cantilever beam 3 in the X-axis direction and the Y-axis direction, and preferably, six strain piezoresistors (R1, R2, R9, R10, R17, and R18) are distributed on the elastic cantilever beam 3-1 in the negative X-axis direction. Wherein R1 and R2 are located at the position where the single-ended portion 301 is close to the supporting frame 1, R17 and R18 are located at the portion where the single-ended portion 302 is close to the mass block 2, and R9 and R10 are located at the position where the middle portion 303 is close to the connection with the single-ended portion 302 and are located at the side of the middle portion 303 close to the supporting frame 1. Six strain piezoresistors (R5, R6, R13, R14, R21 and R22) are distributed on the elastic cantilever beam 3-2 in the positive direction of the X axis. Wherein R5 and R6 are located at the position where the single-ended portion 301 is close to the supporting frame 1, R21 and R22 are located at the portion where the single-ended portion 302 is close to the mass block 2, and R13 and R14 are located at the position where the middle portion 303 is close to the connection with the single-ended portion 302 and are located at the side of the middle portion 303 close to the supporting frame 1. Six strain piezoresistors (R3, R4, R11, R12, R19 and R20) are distributed on the elastic cantilever beam 3-3 in the Y-axis negative direction. Wherein R3 and R4 are located at the position where the single-ended portion 301 is close to the supporting frame 1, R19 and R20 are located at the portion where the single-ended portion 302 is close to the mass block 2, and R11 and R12 are located at the position where the middle portion 303 is close to the connection with the single-ended portion 302 and are located at the side of the middle portion 303 close to the supporting frame 1. Six strain piezoresistors (R7, R8, R15, R16, R23 and R24) are distributed on the elastic cantilever beam 3-4 in the positive direction of the Y axis. Wherein R7 and R8 are located at the position where the single-ended portion 301 is close to the supporting frame 1, R23 and R24 are located at the portion where the single-ended portion 302 is close to the mass block 2, and R15 and R16 are located at the position where the middle portion 303 is close to the connection with the single-ended portion 302 and are located at the side of the middle portion 303 close to the supporting frame 1.

Fig. 5 is a wheatstone bridge diagram for detecting X-axis direction signals formed by connecting the strain sensitive resistors according to the embodiment of the present invention. The strain piezoresistor R5 and the strain piezoresistor R18 are connected in series to form a first bridge arm of the Wheatstone bridge, the strain piezoresistor Rl and the strain piezoresistor R22 are connected in series to form a second bridge arm of the Wheatstone bridge, the strain piezoresistor R11 and the strain piezoresistor R16 are connected in series to form a third bridge arm of the Wheatstone bridge, and the strain piezoresistor R12 and the strain piezoresistor R15 are connected in series to form a fourth bridge arm of the Wheatstone bridge. The strain sensitive resistor R5 of the first arm and the strain sensitive resistor Rl of the second arm are connected to one input terminal of the wheatstone bridge, and the strain sensitive resistor Rl6 of the third arm and the strain sensitive resistor R15 of the fourth arm are connected to the other input terminal of the wheatstone bridge. The strain piezoresistor R18 on the first bridge arm and the strain piezoresistor Rl1 on the third bridge arm are connected to one output end of the Wheatstone bridge, and the strain piezoresistor R22 on the second bridge arm and the strain piezoresistor R12 on the fourth bridge arm are connected to the other output end of the Wheatstone bridge.

Fig. 6 is a wheatstone bridge diagram for detecting Y-axis direction signals formed by connecting the strain sensitive resistors according to the embodiment of the present invention. The strain piezoresistor R7 and the strain piezoresistor R20 are connected in series to form a first bridge arm of the Wheatstone bridge, the strain piezoresistor R3 and the strain piezoresistor R24 are connected in series to form a second bridge arm of the Wheatstone bridge, the strain piezoresistor R10 and the strain piezoresistor R13 are connected in series to form a third bridge arm of the Wheatstone bridge, and the strain piezoresistor R9 and the strain piezoresistor R14 are connected in series to form a fourth bridge arm of the Wheatstone bridge. The strain sensitive resistor R7 of the first arm and the strain sensitive resistor R3 of the second arm are connected to one input terminal of the wheatstone bridge, and the strain sensitive resistor Rl3 of the third arm and the strain sensitive resistor R14 of the fourth arm are connected to the other input terminal of the wheatstone bridge. The strain piezoresistor R20 on the first bridge arm and the strain piezoresistor R10 on the third bridge arm are connected to one output end of the Wheatstone bridge, and the strain piezoresistor R24 on the second bridge arm and the strain piezoresistor R9 on the fourth bridge arm are connected to the other output end of the Wheatstone bridge.

Fig. 7 is a wheatstone bridge diagram for detecting Z-axis direction signals formed by connecting strain sensitive resistors according to an embodiment of the present invention. The strain piezoresistor R2 and the strain piezoresistor R6 are connected in series to form a first bridge arm of the Wheatstone bridge, the strain piezoresistor R17 and the strain piezoresistor R21 are connected in series to form a second bridge arm of the Wheatstone bridge, the strain piezoresistor R19 and the strain piezoresistor R23 are connected in series to form a third bridge arm of the Wheatstone bridge, and the strain piezoresistor R4 and the strain piezoresistor R8 are connected in series to form a fourth bridge arm of the Wheatstone bridge. The strain sensitive resistor R2 of the first arm and the strain sensitive resistor R17 of the second arm are connected to one input terminal of the wheatstone bridge, and the strain sensitive resistor R23 of the third arm and the strain sensitive resistor R8 of the fourth arm are connected to the other input terminal of the wheatstone bridge. The strain piezoresistor R6 on the first bridge arm and the strain piezoresistor R19 on the third bridge arm are connected to one output end of the Wheatstone bridge, and the strain piezoresistor R21 on the second bridge arm and the strain piezoresistor R4 on the fourth bridge arm are connected to the other output end of the Wheatstone bridge.

The following explains the acceleration detection principle of the accelerometer of the utility model. The acceleration of the mass 2 in the accelerometer is considered to have components in the X, Y and Z axes. Without loss of generality, the components of the acceleration of the mass 2 in the X, Y and Z axes are positive.

Referring to fig. 1, under the action of the positive X-axis acceleration component, the resistances of the strain piezoresistors R1, R2, R21 and R22 increase, the resistances of the strain piezoresistors R17, R18, R5 and R6 decrease, and the strain piezoresistors R9, R10, R13 and R4 do not change. At this time, shear stress is generated on the elastic cantilever beam 3-3 in the negative direction of the Y axis and the elastic cantilever beam 3-4 in the positive direction of the Y axis, and when the beam width is far greater than a thousand thicknesses, deformation generated by the shear stress is completely negligible, and it is considered that resistance values of R19, R20, R23, R24, R3, R4, R7, and R8 do not change. However, the shear stress deforms the intermediate portions of the elastic cantilever beams 3-3 and 3-4, so that the resistances of the strain piezoresistors R11 and R16 increase and the resistances of the strain piezoresistors R12 and R15 decrease. Thus, the output signal V in FIG. 5_outReflecting the magnitude of the X-axis acceleration component.

Referring to fig. 1, under the action of the positive Y-axis acceleration component, the resistances of the strain piezoresistors R3, R4, R23 and R24 increase, the resistances of the strain piezoresistors R19, R20, R7 and R8 decrease, and the strain piezoresistors R11, R12, R15 and R6 do not change. At this time, shear stress is generated on the elastic cantilever beam 3-1 in the negative direction of the X axis and the elastic cantilever beam 3-2 in the positive direction of the X axis, and when the beam width is far greater than thousand thickness, deformation generated by the shear stress is completely negligible, and it is considered that resistance values of R17, R18, R21, R22, R1, R2, R5, and R6 do not change. However, it is not limited toThe shear stress deforms the intermediate portions of the elastic cantilever beams 3-1 and 3-2, so that the resistances of the strain piezoresistors R10 and R13 increase and the resistances of the strain piezoresistors R9 and R14 decrease. It can be seen that the Y-axis acceleration component does not affect the resistance of each of the strain piezoresistors in fig. 5, and does not affect the output signal V in fig. 5_outTherefore, the coupling between the X-axis and the Y-axis is negligible.

Referring to fig. 1, under the effect of the positive Z-axis acceleration component, the resistances of the strain piezoresistors R17, R18, R19, R20, R21, R22, R23, and R24 increase, the resistances of the strain piezoresistors R1, R2, R3, R4, R5, R6, R7, and R8 decrease, and the resistances of the strain piezoresistors R9, R10, R11, R12, R13, R14, R15, and R16 do not change. In the wheatstone bridge shown in fig. 5, since the changes of the strain piezoresistors R1 and R5 are the same, the changes of the strain piezoresistors R22 and R18 are the same, the changes of the strain piezoresistors R12 and R11 are the same, and the changes of the strain piezoresistors R15 and R16 are the same, it can be seen that the Z-axis acceleration component does not affect the resistance values of the respective strain piezoresistors in fig. 5, and does not affect the output signal V in fig. 5_outTherefore, the coupling between the X-axis and the Z-axis is negligible.

Similarly, the output signal V in FIG. 6_outThe magnitude of the Y-axis acceleration component is reflected and the coupling between the Y-axis and the X-axis is negligible and the coupling between the Y-axis and the Z-axis is negligible.

Similarly, the output signal V in FIG. 7_outThe magnitude of the Z-axis acceleration component is reflected and the coupling between the Z-axis and the X-axis is negligible and the coupling between the Z-axis and the Y-axis is negligible.

As shown in fig. 1, the supporting frame 1 has a limiting module 4 at each of four inner corners, an X-direction overload resisting gap and a Y-direction overload resisting gap are left between each limiting module 4 and the adjacent elastic cantilever beams 3 and mass blocks 2, and a Z-direction overload resisting gap is left between the mass blocks 2 and the lower cover plate 5 and the upper cover plate 6. When the acceleration component in one direction exceeds the preset maximum load, the overload resisting gap in the direction can prevent the mass block 2 from further moving in the direction, and the effect of protecting and protecting the accelerometer is achieved.

In this embodiment, the supporting frame 1, the mass block 2 and the elastic cantilever beams 3 therebetween are made of an SOI sheet material by conventional standard piezoresistive silicon micromachining process. The twenty-four strain piezoresistors arranged on the elastic beam arm 3 are processed and manufactured by the existing diffusion or ion implantation process. The lower cover plate 5 and the upper cover plate 6 are made of Pyrex glass, and the lower cover plate 5 and the upper cover plate 6 are connected with the supporting frame 1 through electrostatic bonding.

In this embodiment, the overall size of the accelerometer is 6000 μm in length, 6000 μm in width, and 2000 μm in height. Wherein the side length of the mass block is 2400 mu m, and the thickness of the mass block is 300 mu m; the beam length of the elastic cantilever beam is 800 mu m, the width of a single-end part beam is 200 mu m, the width of a double-end part beam is 1200 and the thickness of the beam is 20 mu m; the side length of the supporting frame is 4000 mu m, and the width of the frame is 1000 mu m.

In the embodiment, when the acceleration components of the X axis and the Y axis are measured, not only the compressive stress and the tensile stress directly caused by the components are utilized, but also the compressive stress and the tensile stress caused by the shear stress caused by the components are utilized, so that the embodiment has higher sensitivity and accuracy. In addition, the compound cantilever beam adopted by the embodiment has better rigidity compared with the common elastic cantilever beam at present, is beneficial to resetting the mass block 2, reduces the system error and improves the measurement precision. Furthermore, shear stress in the Y-axis (X-axis) direction caused by the X-axis (Y-axis) acceleration component is mainly concentrated in the middle portion 303 of the compound cantilever beam, reducing the influence of the shear stress on the strain piezoresistors located in the single-ended portion 301 and the double-ended portion 302 of the compound cantilever beam, and reducing the inter-axis coupling of the accelerometer.

Optionally, fig. 8 is a schematic structural diagram of another triaxial piezoresistive accelerometer according to an embodiment of the present invention, and fig. 9 is a partial enlarged view of fig. 8. As shown in fig. 8 and 9, in the present embodiment, the elastic cantilever beam 3 is a compound cantilever beam, and includes a single-ended portion 301, a double-ended portion 302, and an intermediate portion 303 connecting the single-ended portion 301 and the double-ended portion 302. In this embodiment, the double end portions 302 of the elastic cantilever beams 3 are connected to the mass block 2, and the single end portions 301 of the elastic cantilever beams 3 are connected to the supporting frame 1. Six strain piezoresistors (R1, R2, R9, R10, R17 and R18) are distributed on the elastic cantilever beam 3-1 in the X-axis negative direction. Wherein R1 and R2 are located at the single end portion 301 near the support rim 1, R17 and R18 are located at the double end portion 302 near the mass 2, and R9 and R10 are located at the middle portion 303 near the connection with the single end portion 301 and at the side of the middle portion 303 near the support rim 1. Six strain piezoresistors (R5, R6, R13, R14, R21 and R22) are distributed on the elastic cantilever beam 3-2 in the positive direction of the X axis. Wherein R5 and R6 are located at the single end portion 301 near the support rim 1, R21 and R22 are located at the double end portion 302 near the mass 2, and R13 and R14 are located at the middle portion 303 near the connection with the single end portion 301 and at the side of the middle portion 303 near the support rim 1. Six strain piezoresistors (R3, R4, R11, R12, R19 and R20) are distributed on the elastic cantilever beam 3-3 in the Y-axis negative direction. Wherein R3 and R4 are located at the single end portion 301 near the support rim 1, R19 and R20 are located at the double end portion 302 near the mass 2, and R11 and R12 are located at the middle portion 303 near the connection with the single end portion 301 and at the side of the middle portion 303 near the support rim 1. Six strain piezoresistors (R7, R8, R15, R16, R23 and R24) are distributed on the elastic cantilever beam 3-4 in the positive direction of the Y axis. Wherein R7 and R8 are located at the single end portion 301 near the support rim 1, R23 and R24 are located at the double end portion 302 near the mass 2, and R15 and R16 are located at the middle portion 303 near the connection with the single end portion 301 and at the side of the middle portion 303 near the support rim 1.

It should be noted that, in the two embodiments shown in fig. 1 and fig. 8, the numbers of the strain piezoresistors R9 and R10, R11 and R12, R13 and R14, and R15 and R16 are exchanged. As can be seen from the analysis method of the embodiment shown in fig. 1, in the embodiment shown in fig. 8, the output signal Vout in fig. 5 reflects the magnitude of the acceleration component of the X-axis, and the coupling between the X-axis and the Y-axis is negligible, and the coupling between the X-axis and the Z-axis is negligible; output signal V in FIG. 6_outThe magnitude of the acceleration component of the Y axis is reflected, the coupling between the Y axis and the X axis can be ignored, and the coupling between the Y axis and the Z axis can be ignored; similarly, the output signal Vout in fig. 7 reflects the magnitude of the Z-axis acceleration component,and the coupling between the Z-axis and the X-axis is negligible and the coupling between the Z-axis and the Y-axis is negligible.

The above description is only an embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-axis piezoresistive accelerometer, characterized in that: the device comprises a supporting frame (1), a mass block (2) and elastic cantilever beams (3), wherein the mass block (2) is suspended at the central position of the supporting frame (1) through the elastic cantilever beams (3), a plurality of strain piezoresistors with equal resistance values are symmetrically distributed on the elastic cantilever beams (3) between the supporting frame (1) and the mass block (2), four inner corners of the supporting frame (1) are respectively provided with a limiting module (4), X-direction and Y-direction overload-resistant gaps are formed between the limiting modules (4) and the adjacent elastic cantilever beams (3) and the mass block (2), the upper side and the lower side of the supporting frame (1) are respectively provided with a lower cover plate (5) and an upper cover plate (6), and Z-direction overload-resistant gaps are formed between the mass block (2) and the lower cover plate (5) and the upper cover plate (6), the elastic cantilever beam (3) comprises a single-ended portion (301), a double-ended portion (302), and a middle portion (303) connecting the single-ended portion (301) and the double-ended portion (302), wherein the single-ended portion (301) is connected with the supporting frame (1), and the double-ended portion (302) is connected with the mass block (2).

2. The tri-axial piezoresistive accelerometer according to claim 1, wherein: the number of the elastic cantilever beams (3) is four, and six strain piezoresistors are arranged on each elastic cantilever beam (3).

3. The tri-axial piezoresistive accelerometer according to claim 1, wherein: the supporting frame (1) is provided with a plurality of metal pads (7), the metal pads (7) are symmetrically and uniformly distributed along the axis of the supporting frame (1), and the metal pads (7) on each edge of the supporting frame (1) are electrically connected with the strain piezoresistors on the adjacent elastic cantilever beams (3) in a one-to-one correspondence mode through metal leads (8).

4. A triaxial piezoresistive accelerometer according to claim 3, wherein: the number of the metal pads (7) on the supporting frame (1) is twenty-four, and each edge of the supporting frame (1) is provided with six metal pads (7).

5. The tri-axial piezoresistive accelerometer according to claim 1, wherein: the mass block (2) is in a centrosymmetric shape.

6. The tri-axial piezoresistive accelerometer according to claim 5, wherein: the mass block (2) is square.