High-precision subminiature inertial measurement combination based on MEMS device

Abstract

The invention provides a high-precision subminiature inertial measurement combination based on an MEMS device, and relates to the technical field of MEMS inertial measurement combinations. According to the inertial measurement combination, a three-axis MEMS accelerometer chip and three single-axis MEMS gyroscope chips are respectively arranged on a rigid printed board, and acquired angular velocity information and acceleration information are respectively transmitted to the rigid printed board on which a processor chip is positioned through a flexible printed board; and working software embedded in the processor chip outputs the processed acceleration information and angular velocity information through an external electrical interface according to a system error model. The cable-free information processing circuit is formed in the mode, the system structure miniaturization problem in a limited space and the MEMS chip low-stress orthogonal installation problem can be solved, MEMS devices conduct information interaction, the utilization rate of the limited space of an inertial measurement combination can be effectively increased, cable installation space does not need to be reserved, and the cost is reduced. Therefore, the inertial measurement combination achieves the miniaturization effect.

Description

Technical Field

[0001] This specification relates to the technical field of MEMS inertial measurement units, and in particular to a high-precision ultra-small inertial measurement unit based on MEMS devices. Background Art

[0002] With the development of micro-electromechanical inertial technology, higher requirements are being placed on the miniaturization of MEMS inertial systems. As more and more miniature weapon systems are gradually entering the military field, this requires that inertial measurement units (IMUs) be made smaller and smaller while also taking into account the accuracy and performance of the system. In this context, there is an urgent need to conduct research on the miniaturized system integration design technology of MEMS inertial measurement units to solve the problem of miniaturized integration of inertial measurement systems in limited spaces and to achieve high-precision, domestically produced inertial measurement units that meet the system requirements at the lowest cost and smallest structural size.

[0003] Currently, there are many miniaturized MEMS inertial measurement systems (IMSs), with common dimensions of 44.8mm × 38.6mm × 21.5mm or 25.8mm × 25.8mm × 21.5mm. These systems utilize multiple circuit boards interconnected by wirebonds, resulting in complex assembly and high costs. However, no IMS design solution has been found that can simultaneously meet the requirements of low cost, high precision, localization, and a large range within a 25mm × 20mm × 15mm footprint. Summary of the Invention

[0004] The purpose of this specification is to provide a high-precision ultra-small inertial measurement assembly based on MEMS devices, which can overcome the above-mentioned defects of existing MEMS inertial measurement assemblies.

[0005] The embodiments of this specification are implemented as follows:

[0006] A high-precision ultra-small inertial measurement assembly based on MEMS devices, including a MEMS three-axis accelerometer chip and three single-axis MEMS gyroscope chips; the MEMS three-axis accelerometer chip and the three single-axis MEMS gyroscope chips are all domestically produced devices;

[0007] The three single-axis MEMS gyroscope chips are stacked on three rigid printed circuit boards, and the arrangement directions of the three single-axis MEMS gyroscope chips are perpendicular to each other;

[0008] The three-axis MEMS accelerometer chip is stacked on a rigid printed circuit board;

[0009] The three-axis MEMS accelerometer chip and three single-axis MEMS gyroscope chips placed on the rigid printed circuit board can respectively transmit the collected angular velocity information and acceleration information to the rigid printed circuit board where the processor chip is located. The rigid printed circuit boards can exchange information through the flexible printed circuit board, and the rigid printed circuit board where the processor chip with embedded working software is located can output the processed acceleration information and angular velocity information through the external electrical interface.

[0010] Some embodiments of the present specification also include a shell assembly, which includes a shell body and a cover plate. The shell body itself cooperates to form a accommodating chamber with an opening at one end, and the cover plate can close the opening; the three single-axis MEMS gyroscope chips and the three-axis MEMS accelerometer chip are respectively arranged in the accommodating chamber.

[0011] In some embodiments of the present specification, the three uniaxial MEMS gyroscope chips are stacked on a first rigid printed board, a second rigid printed board, and a third rigid printed board, respectively; the three-axis MEMS accelerometer chip is stacked on a fourth rigid printed board; and the first rigid printed board, the second rigid printed board, and the fourth rigid printed board are connected by a flexible printed board.

[0012] In some embodiments of the present specification, the shell body has a bottom wall and a first circumferential side wall, a second circumferential side wall, a third circumferential side wall and a fourth circumferential side wall, the bottom wall, the first circumferential side wall and the second circumferential side wall are respectively provided with the single-axis MEMS gyroscope chip, the third circumferential side wall is provided with the three-axis MEMS accelerometer chip, the first circumferential side wall and the second circumferential side wall are adjacent side walls, the fourth circumferential side wall is provided with a fifth rigid printed board, the fifth rigid printed board is respectively connected to the fourth rigid printed board and the third rigid printed board through a flexible printed board, and the fifth rigid printed board can output the processed acceleration information and angular velocity information.

[0013] In some embodiments of this specification, the fourth circumferential side wall is provided with an external electrical interface, and the external electrical interface is connected to the fifth rigid printed circuit board.

[0014] In some embodiments of the present specification, the bottom wall is provided with a first groove, a second groove, a third groove and a fourth groove. The first groove, the second groove and the third groove can be respectively clamped with the first rigid printed board, the second rigid printed board and the fourth rigid printed board on the side away from the cover plate, and the fourth groove can be clamped with the single-axis MEMS gyroscope chip provided on the third rigid printed board.

[0015] In some embodiments of the present specification, silicone rubber is disposed in the first groove, the second groove, the third groove, and the fourth groove.

[0016] In some embodiments of the present specification, a circumferential groove is provided on a side of the shell body close to the cover plate, the shell body is connected to the cover plate through the circumferential groove, and the groove height of the circumferential groove is consistent with the height of the cover plate.

[0017] In some embodiments of the present specification, the length, width and height of the shell body are 24.8 mm to 25.2 mm, 19.8 mm to 20.2 mm and 14.8 mm to 15.2 mm, respectively.

[0018] In some embodiments of this specification, the rigid printed circuit board where the processor chip is located can perform temperature compensation processing and error compensation processing on the collected acceleration information and angular velocity information according to the collected temperature information.

[0019] The embodiments of this specification have at least the following advantages or beneficial effects:

[0020] Compared to existing technologies, this high-precision, ultra-compact inertial measurement unit (IMU) based on MEMS devices achieves a cable-free information processing circuit by placing the MEMS devices on a rigid printed circuit board (PCB) and then placing a flexible PCB between the rigid PCBs. This cable-free layout and installation approach, achieved by combining rigid and flexible PCBs, addresses the challenges of miniaturizing system structures within limited spaces and ensuring low-stress, orthogonal installation of MEMS chips. This allows for information exchange between MEMS devices, effectively improving the utilization of the IMU's limited space, eliminating the need for reserved cable installation space and miniaturizing the IMU. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of this specification, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of this specification and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 Schematic diagram of the exploded structure of the high-precision ultra-small inertial measurement unit based on MEMS devices provided for this specification;

[0023] Figure 2 A schematic diagram of the structure of a high-precision ultra-small inertial measurement system based on MEMS devices provided in this manual;

[0024] Figure 3Schematic diagram of the configuration of the MEMS tri-axis accelerometer chip and three single-axis MEMS gyroscope chips provided in this manual;

[0025] Figure 4 A top view schematic diagram of a high-precision ultra-small inertial measurement unit based on MEMS devices provided in this specification;

[0026] Figure 5 A side view schematic diagram of a high-precision ultra-small inertial measurement unit based on MEMS devices provided in this specification;

[0027] Figure 6 Schematic diagram of a high-precision, ultra-small inertial measurement unit based on MEMS devices provided for this specification.

[0028] Icons: 1. MEMS three-axis accelerometer chip; 2. Single-axis MEMS gyroscope chip; 3. Shell body; 4. Cover plate; 5. First rigid printed circuit board; 6. Second rigid printed circuit board; 7. Third rigid printed circuit board; 8. Fourth rigid printed circuit board; 9. Fifth rigid printed circuit board; 10. External electrical interface; 11. Mounting through hole; 12. First groove; 13. Second groove; 14. Third groove; 15. Fourth groove; 16. Circumferential groove; 17. Flexible printed circuit board; 18. External cable. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this specification more clear, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of this specification. Obviously, the described embodiments are part of the embodiments of this specification, not all of the embodiments. Generally, the components of the embodiments of this specification described and shown in the drawings herein can be arranged and designed in a variety of different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present specification provided in the accompanying drawings is not intended to limit the scope of the present specification as claimed, but merely represents selected embodiments of the present specification. Based on the embodiments in this specification, all other embodiments obtained by persons of ordinary skill in the art without making any creative effort are within the scope of protection of this specification.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0032] In the description of the embodiments of this specification, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the accompanying drawings, or the orientation or position relationship in which the product of this specification is usually placed when in use. It is only for the convenience of describing this specification and simplifying the description, and does not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it should not be understood as a limitation on this specification. In addition, if the terms "first", "second", "third", etc. appear, they are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0033] Furthermore, the use of terms such as "horizontal," "vertical," and "overhanging" does not necessarily mean that the component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0034] In the description of the embodiments of this specification, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this specification based on specific circumstances.

[0035] Please refer to Figures 1 to 6 An embodiment of the present specification provides a high-precision ultra-small inertial measurement assembly based on MEMS devices, which mainly includes a MEMS three-axis accelerometer chip 1 and three single-axis MEMS gyroscope chips 2; the MEMS three-axis accelerometer chip 1 and the three single-axis MEMS gyroscope chips 2 are all domestically produced devices;

[0036] The three uniaxial MEMS gyroscope chips 2 are stacked on three rigid printed circuit boards, and the arrangement directions of the three uniaxial MEMS gyroscope chips 2 are perpendicular to each other.

[0037] The three-axis MEMS accelerometer chip 1 is stacked on a rigid printed circuit board;

[0038] The three-axis MEMS accelerometer chip 1 and the three single-axis MEMS gyroscope chips 2 placed on the rigid printed circuit board can respectively transmit the collected angular velocity information and acceleration information to the rigid printed circuit board where the processor chip is located. The rigid printed circuit boards can exchange information through the flexible printed circuit board 17, and the rigid printed circuit board where the processor chip with embedded working software is located can output the processed acceleration information and angular velocity information through the external electrical interface.

[0039] In this embodiment, the rigid printed circuit board where the processor chip is located can perform temperature compensation processing and error compensation processing on the collected acceleration information and angular velocity information according to the collected temperature information in accordance with the system error model.

[0040] In this embodiment, the rigid printed circuit board is provided with a processor chip, which is provided with embedded working software. The processor chip can read the acceleration information and angular velocity information of the three-axis MEMS accelerometer chip and the three single-axis MEMS gyroscope chips 2 through the SPI interface of the processor chip. At the same time, the temperature information can also be read, so as to perform system error compensation and temperature compensation calculations on the acceleration channel and angular velocity channel according to the inertial measurement combination error compensation model based on the temperature information.

[0041] It should be noted here that the size of the above-mentioned domestic MEMS devices under the same precision level is usually 11mm×11mm×3mm, which is larger than that of imported MEMS devices.

[0042] In this embodiment, the information processing circuit is bonded by silicone rubber, thereby achieving a low-stress orthogonal mounting effect of the MEMS device.

[0043] Specifically, the above-mentioned inertial measurement assembly is formed by placing the above-mentioned MEMS devices on a rigid printed circuit board, and then forming an information processing circuit by arranging a flexible printed circuit board 17 between the rigid printed circuit boards. It can be seen that the above-mentioned four MEMS devices are arranged and installed in a cable-free manner, which enables the MEMS devices to exchange information, effectively improving the utilization rate of the limited space of the inertial measurement assembly. There is no need to reserve installation space for cables, so that the inertial measurement assembly can achieve a miniaturized effect, thereby solving the problem of miniaturization of the system structure of the inertial measurement assembly in a limited space and the problem of low-stress orthogonal installation of MEMS chips.

[0044] In this embodiment, the three single-axis MEMS gyroscope chips 2 are arranged in directions perpendicular to each other, so that the MEMS gyroscope chips can be installed orthogonally, thereby obtaining angular velocity information in three directions.

[0045] In this embodiment, the measurement accuracy of the acceleration channel reaches 0.2 mg, and the measurement accuracy of the angular velocity channel reaches 2° / h.

[0046] In this embodiment, a shell assembly is also included, which includes a shell body 3 and a cover plate 4. The shell body 3 itself cooperates to form a accommodating chamber with an opening at one end, and the cover plate 4 can close the opening; the three single-axis MEMS gyroscope chips 2 and the three-axis MEMS accelerometer chip are respectively arranged in the accommodating chamber.

[0047] In this embodiment, the length, width and height of the shell body 3 are 24.8 mm to 25.2 mm, 19.8 mm to 20.2 mm and 14.8 mm to 15.2 mm respectively.

[0048] In this embodiment, the three uniaxial MEMS gyroscope chips 2 are stacked on a first rigid printed board 5, a second rigid printed board 6, and a third rigid printed board 7, respectively. The triaxial MEMS accelerometer chip is stacked on a fourth rigid printed board 8. The first rigid printed board 5, the second rigid printed board 6, and the fourth rigid printed board 8 are connected by a flexible printed board 17. This arrangement enables the three uniaxial MEMS gyroscope chips to be orthogonally mounted within the housing chamber with low stress.

[0049] In this embodiment, the shell body 3 has a bottom wall and a first circumferential side wall, a second circumferential side wall, a third circumferential side wall and a fourth circumferential side wall, the bottom wall, the first circumferential side wall and the second circumferential side wall are respectively provided with the single-axis MEMS gyroscope chip 2, the third circumferential side wall is provided with the three-axis MEMS accelerometer chip, the first circumferential side wall and the second circumferential side wall are adjacent side walls, the fourth circumferential side wall is provided with a fifth rigid printed board 9, the fifth rigid printed board 9 is respectively connected to the fourth rigid printed board 8 and the third rigid printed board 7 through a flexible printed board 17, and the fifth rigid printed board 9 can output the processed acceleration information and angular velocity information.

[0050] In detail, by arranging the MEMS three-axis accelerometer chip 1 and two uniaxial MEMS gyroscope chips 2 on three adjacent circumferential side walls, especially the two uniaxial MEMS gyroscope chips 2 should be arranged on two adjacent circumferential side walls, and the other uniaxial MEMS gyroscope chip 2 is arranged on the bottom wall, the above four MEMS devices can be arranged in a housing assembly with an outer dimension of 25mm×20mm×15mm, and at the same time, the problem of low-stress orthogonal installation of MEMS chips can be solved.

[0051] In this embodiment, the above-mentioned single-axis MEMS gyroscope chip 2 can transmit the angular velocity information in each direction collected or measured by it to the rigid printed board where the processor chip is located. The processor chip set on the rigid printed board can process the above-mentioned angular velocity information. The first rigid printed board 5 can exchange information with the second rigid printed board 6 through the set flexible printed board 17. The second rigid printed board 6 can exchange information with the fourth rigid printed board 8 through the set flexible printed board 17. The fourth rigid printed board 8 can exchange information with the fifth rigid printed board 9 through the flexible printed board 17; the third rigid printed board 7 can transmit the processed angular velocity information to the above-mentioned fifth rigid printed board 9 through the flexible printed board 17 for output.

[0052] In this embodiment, the processor chip may be preferably arranged on a side of the third rigid printed circuit board 7 away from the single-axis MEMS gyroscope chip.

[0053] In this embodiment, there are gaps between the rigid printed circuit boards, and the flexible printed circuit boards 17 are disposed at the gaps.

[0054] Through the above-mentioned setting method, the above-mentioned inertial measurement combination not only has the advantages of light weight, small size and low cost, but also has the advantage of high precision. It has good application prospects in the fields of low-cost miniaturized equipment such as drones, guided bombs, micro missiles, etc., and has good economic efficiency.

[0055] In this embodiment, the fourth circumferential side wall is provided with an external electrical interface 10 , and the external electrical interface 10 is connected to the fifth rigid printed circuit board 9 .

[0056] In this embodiment, the sizes of the first rigid printed board 5, the second rigid printed board 6, the third rigid printed board 7, and the fourth rigid printed board 8 are slightly larger than the sizes of the MEMS device, and the size of the fifth rigid printed board 9 is smaller than the sizes of the first to fourth rigid printed boards 8. Their sizes should only meet the connection requirements with the external electrical interface 10.

[0057] In this embodiment, the fifth rigid printed circuit board 9 is connected to an external cable 18 , and the external cable 18 can pass through the external electrical interface 10 to be connected to a host computer.

[0058] In this embodiment, the external electrical interface 10 is an RS422 interface. To improve the use and maintenance performance of the inertial measurement unit, the inertial measurement unit can establish communication with the host computer through the RS422 interface to upload and update the calibration error coefficient and working software to the internal FLASH storage space of the inertial measurement unit.

[0059] In this embodiment, the bottom wall is provided with a first groove 12, a second groove 13, a third groove 14 and a fourth groove 15. The first groove 12, the second groove 13 and the third groove 14 can be respectively clamped with the first rigid printed board 5, the second rigid printed board 6 and the fourth rigid printed board 8 away from the side of the cover plate 4, and the fourth groove 15 can be clamped with the single-axis MEMS gyroscope chip 2 provided on the third rigid printed board 7.

[0060] In this embodiment, the groove dimensions of the first groove 12, the second groove 13, and the third groove 14 are respectively adapted to the thicknesses of the first rigid printed board 5, the second rigid printed board 6, and the fourth rigid printed board 8. The groove dimension of the fourth groove 15 is adapted to the single-axis MEMS gyroscope chip 2 arranged on the third rigid printed board 7. By providing the first groove 12, the second groove 13, the third groove 14, and the fourth groove 15, the stability of the MEMS device in the accommodation chamber can be effectively enhanced.

[0061] In this embodiment, silicone rubber is provided in the first groove 12, the second groove 13, the third groove 14, and the fourth groove 15. By filling the first rigid printed board 5, the second rigid printed board 6, the fourth rigid printed board 8, and the single-axis MEMS gyroscope chip 2 provided on the third rigid printed board 7 with the silicone rubber, the first rigid printed board 5, the second rigid printed board 6, the fourth rigid printed board 8, and the single-axis MEMS gyroscope chip 2 provided on the third rigid printed board 7 are bonded to the bottom wall. This not only allows the MEMS device to be more stably fixed to the bottom wall of the housing body 3, but also enhances the vibration reduction effect of the inertial measurement assembly by providing the silicone rubber.

[0062] In this embodiment, a circumferential groove 16 is provided on one side of the housing 3 near the cover plate 4. The housing 3 is connected to the cover plate 4 via the circumferential groove 16, and the height of the circumferential groove 16 is consistent with the height of the cover plate 4. This arrangement ensures that the outer side of the inertial measurement assembly is consistent, facilitating placement in a limited space.

[0063] In this embodiment, mounting through holes 11 are provided at the four corners of the shell body 3 to facilitate the installation of screws. The shape of the above-mentioned accommodating chamber is a cube with notches at the four corners, and its volume is smaller than the outer dimensions of the above-mentioned shell assembly. The shape formed by the above-mentioned MEMS device and the rigid printed circuit board (that is, the shape formed by the structural setting) is exactly consistent with the above-mentioned cube with notches at the four corners. It can be seen that the above-mentioned method can greatly improve the space utilization of the above-mentioned accommodating chamber and further reduce the volume of the inertial measurement combination.

[0064] In this embodiment, the above-mentioned inertial measurement assembly has a simple structural setting, few parts, and low processing cost. Moreover, the above-mentioned inertial measurement assembly is configured with domestically produced components (i.e., produced by domestic manufacturers). While having the advantages of high output accuracy and a large measurement range, it also has the advantage of low cost. In addition, it can adapt to the application requirements of upper-level systems of different sizes and different performances, and has broad application prospects and good economic efficiency.

[0065] In this embodiment, the above-mentioned inertial measurement assembly has an external dimension of only 25 mm×20 mm×15 mm and weighs less than 30 g.

[0066] The above are merely preferred embodiments of this specification and are not intended to limit this specification. Those skilled in the art will readily appreciate that this specification is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this specification shall be within the scope of protection of this specification.

Claims

1. A high-precision ultra-small inertial measurement unit based on MEMS devices, characterized in that: It includes a MEMS three-axis accelerometer chip and three single-axis MEMS gyroscope chips; the MEMS three-axis accelerometer chip and the three single-axis MEMS gyroscope chips are all domestic devices; The three single-axis MEMS gyroscope chips are stacked on three rigid printed circuit boards, and the arrangement directions of the three single-axis MEMS gyroscope chips are perpendicular to each other; The three-axis MEMS accelerometer chip is stacked on a rigid printed circuit board; The three-axis MEMS accelerometer chip and three single-axis MEMS gyroscope chips placed on the rigid printed circuit board can respectively transmit the collected angular velocity information and acceleration information to the rigid printed circuit board where the processor chip is located. The rigid printed circuit boards can exchange information through the flexible printed circuit board, and the rigid printed circuit board where the processor chip with embedded working software is located can output the processed acceleration information and angular velocity information through the external electrical interface.

2. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 1, characterized in that: It also includes a shell component, which includes a shell body and a cover plate. The shell body itself cooperates to form a accommodating chamber with an opening at one end, and the cover plate can close the opening; the three single-axis MEMS gyroscope chips and the three-axis MEMS accelerometer chip are respectively arranged in the accommodating chamber.

3. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 2, characterized in that: The three single-axis MEMS gyroscope chips are stacked on the first rigid printed board, the second rigid printed board and the third rigid printed board respectively, and the three-axis MEMS accelerometer chip is stacked on the fourth rigid printed board. The first rigid printed board, the second rigid printed board and the fourth rigid printed board are connected by a flexible printed board.

4. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 3, characterized in that: The shell body has a bottom wall and a first circumferential side wall, a second circumferential side wall, a third circumferential side wall and a fourth circumferential side wall. The bottom wall, the first circumferential side wall and the second circumferential side wall are respectively provided with the single-axis MEMS gyroscope chip, the third circumferential side wall is provided with the three-axis MEMS accelerometer chip, the first circumferential side wall and the second circumferential side wall are adjacent side walls, and the fourth circumferential side wall is provided with a fifth rigid printed board. The fifth rigid printed board is respectively connected to the fourth rigid printed board and the third rigid printed board through a flexible printed board, and the fifth rigid printed board can output the processed acceleration information and angular velocity information.

5. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 4, characterized in that: The fourth circumferential side wall is provided with an external electrical interface, and the external electrical interface is connected to the fifth rigid printed circuit board.

6. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 4, characterized in that: The bottom wall is provided with a first groove, a second groove, a third groove and a fourth groove. The first groove, the second groove and the third groove can be respectively clamped with the first rigid printed circuit board, the second rigid printed circuit board and the fourth rigid printed circuit board on the side away from the cover plate. The fourth groove can be clamped with the single-axis MEMS gyroscope chip arranged on the third rigid printed circuit board.

7. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 6, characterized in that: Silicon rubber is provided in the first groove, the second groove, the third groove and the fourth groove.

8. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 2, characterized in that: A circumferential groove is provided on one side of the shell body close to the cover plate. The shell body is connected to the cover plate through the circumferential groove, and the groove height of the circumferential groove is consistent with the height of the cover plate.

9. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 8, characterized in that: The length, width and height of the shell body are 24.8mm-25.2mm, 19.8mm-20.2mm and 14.8mm-15.2mm respectively.

10. The high-precision ultra-small inertial measurement unit based on MEMS devices according to claim 1, characterized in that: The rigid printed circuit board where the processor chip is located can perform temperature compensation processing and error compensation processing on the collected acceleration information and angular velocity information according to the collected temperature information.

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