An inertial navigation measurement component

Abstract

The present invention discloses an inertial navigation measurement assembly, comprising an IMU bracket in a rectangular box structure, wherein two adjacent sides of the IMU bracket are open-ended. Gyroscopes are mounted on the three adjacent side walls of the IMU bracket corresponding to the X-axis, Y-axis, and Z-axis, respectively. A through hole or groove is provided at the center of each gyroscope, and an accelerometer is mounted in each through hole or groove. A plurality of arms extending along the Y-axis are provided on two opposing side walls perpendicular to the X-axis, and shock absorbers are mounted on each arm. A cavity is provided within the IMU bracket, and a circuit board assembly is mounted within the cavity. The gyroscope and accelerometer are both connected to the circuit board assembly. The present invention has a compact structure, a small size, and a built-in shock-absorbing device, exhibiting excellent miniaturization, shock resistance, and earthquake resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of inertial navigation equipment, and in particular to an inertial navigation measurement component. Background Art

[0002] Strapdown positioning and orientation inertial navigation systems are generally installed directly on a carrier and fastened to it, providing the carrier with attitude and position information. During transportation and actual use, the vibration environment is relatively harsh. When the precision components inside the inertial navigation equipment, such as the three-axis gyroscope and three-axis accelerometer, exceed their designed vibration resistance performance indicators, the device performance will deteriorate or even cause damage. To improve the seismic performance of the inertial navigation equipment, a shock absorber is generally installed on the outside of the inertial navigation equipment. However, with the trend of miniaturization of strapdown inertial navigation equipment, the installation space for strapdown inertial navigation systems is generally limited. Furthermore, in traditional inertial navigation equipment, the gyroscope and accelerometer are installed separately, each occupying a separate space. Therefore, the overall structure is not compact and occupies a large space. Furthermore, the installation of a shock absorber makes the entire device larger, making it difficult to install in a limited space and difficult to meet the growing demand for miniaturization. Summary of the Invention

[0003] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is: to provide an inertial navigation measurement component, which solves the problem that the prior art structure is not compact enough, is difficult to meet the miniaturization requirements, and requires the installation of a shock-absorbing device to meet the impact and seismic performance of the inertial navigation equipment.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] An inertial navigation measurement assembly includes an IMU bracket in a rectangular box structure, wherein two adjacent sides of the IMU bracket are open ends, a Z axis is defined as being perpendicular to a plane on which one of the open ends is located, a Y axis is defined as being perpendicular to a plane on which the other open end is located, and an X axis is defined as being perpendicular to both the Y axis and the Z axis;

[0006] An X-axis gyroscope, a Y-axis gyroscope, and a Z-axis gyroscope are respectively installed on three adjacent side walls of the IMU bracket corresponding to the X-axis, Y-axis, and Z-axis, and a through hole or groove is opened at the center of the X-axis gyroscope, the Y-axis gyroscope, and the Z-axis gyroscope, and an accelerometer is installed in the through hole or groove;

[0007] A plurality of supporting arms extending along the Y-axis are provided on two opposite side walls perpendicular to the X-axis, and shock absorbers are installed on the supporting arms;

[0008] A cavity is provided inside the IMU bracket, a circuit board assembly is installed in the cavity, and the X-axis gyroscope, Y-axis gyroscope, Z-axis gyroscope and accelerometer are all connected to the circuit board assembly.

[0009] As an optimization, the support arm is a plate-like structure perpendicular to the Z axis; the shock absorber is a cylindrical structure with its axis parallel to the Z axis and is installed on both sides of the support arm along the Z axis.

[0010] As an optimization, the shock absorber includes a circular base, and a shock-absorbing rubber is provided at one end of the base. The base is used to press the shock-absorbing rubber to make it fit with the support arm.

[0011] As an optimization, two of the arms are provided on each of the two opposite side walls perpendicular to the X-axis, and the arms on the same side wall are located at both ends of the diagonal of the side wall, and the diagonals corresponding to the two arms on the side wall are cross-arranged with the diagonals corresponding to the two arms on the other side wall.

[0012] As an optimization, the arm is perpendicular to the X-axis and the side surface facing away from the IUM bracket is flush with the corresponding side surface of the IMU bracket.

[0013] As an optimization, the top surfaces of the X-axis gyroscope, the Y-axis gyroscope, and the Z-axis gyroscope are not lower than the top surfaces of the corresponding accelerometers.

[0014] As an optimization, the circuit board assembly includes two oppositely arranged circuit board mounting brackets, which are installed in the cavity of the IMU bracket; multiple mounting slots are arranged in parallel on opposite sides of the two circuit board mounting brackets, and a circuit board is installed between the two opposite mounting slots, and the circuit board is respectively connected to the X-axis gyroscope, Y-axis gyroscope, Z-axis gyroscope and accelerometer.

[0015] As an optimization, the circuit board assembly further includes a base plate, which is perpendicular to the circuit board and has a plurality of input interfaces and corresponding output interfaces provided on the base plate, wherein the input interfaces are respectively connected to each circuit board.

[0016] As an optimization, the circuit board mounting bracket is installed on the inner sides of two opposite side walls of the IMU bracket along the X-axis direction, and the circuit board is arranged perpendicular to the Z-axis.

[0017] As an optimization, a base plate bracket is further provided on the base plate, and the base plate bracket is fixed on the end face of the open end of the IMU bracket corresponding to the Y-axis.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] The present invention integrates the entire inertial measurement unit (IMU) into a whole and fixes it in an equipment box with screws. The accelerometer is placed in the fiber optic ring of the gyroscope to reduce its size. The vibration damper is installed on the support arm of the IMU. The support arm adopts a four-point spatial installation method. The extension direction of each support arm is restricted to align with the extension direction of the fiber optic ring or circuit board assembly of each gyroscope. The space occupied by the entire inertial navigation measurement unit is rectangular, without occupying excess space and having any protruding parts. The circuit board is installed on a circuit board mounting bracket, which is fastened to the interior of the IMU bracket. The data signal is led out from the bottom plate on the mounting bracket. The overall structure is compact, with a built-in vibration damping device, and has good miniaturization, impact resistance, and seismic resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the main structure of the present invention;

[0021] Figure 2 for Figure 1 A top view of

[0022] Figure 3 for Figure 1 Right view of;

[0023] Figure 4 is the Z-axis amplitude change curve of the present invention;

[0024] Figure 5 is the X-axis amplitude change curve of the present invention;

[0025] Figure 6 It is the Y-axis amplitude change curve of the present invention;

[0026] Figure 7 is the root mean square (RMS) value of acceleration of the present invention;

[0027] Figure 8 is the root mean square (RMS) value of the random vibration acceleration of the Z-direction D1 spectrum of the present invention;

[0028] Figure 9 is the root mean square (RMS) value of the random vibration acceleration of the X-axis D1 spectrum of the present invention;

[0029] Figure 10 is the root mean square (RMS) value of the random vibration acceleration of the D1 spectrum in the Y direction of the present invention;

[0030] In the figure, 1-IMU bracket, 2-X-axis gyroscope, 3-Y-axis gyroscope, 4-Z-axis gyroscope, 5-accelerometer, 6-support arm, 7-shock absorber, 8-circuit board mounting bracket, 9-circuit board, 10-base plate, 11-output interface, 12-input interface, 13-base plate bracket. DETAILED DESCRIPTION

[0031] The present invention will be described in further detail below with reference to the accompanying drawings.

[0032] Specific implementation: see Figure 1-3 ,

[0033] An inertial navigation measurement assembly includes an IMU bracket 1 with a rectangular box structure, wherein two adjacent sides of the IMU bracket 1 are open ends, the Z axis is defined as perpendicular to the plane where one of the open ends is located, the Y axis is perpendicular to the plane where the other open end is located, and the X axis is perpendicular to the Y axis and the Z axis.

[0034] An X-axis gyroscope 2, a Y-axis gyroscope 3, and a Z-axis gyroscope 4 are mounted on the three adjacent side walls of the IMU bracket 1 corresponding to the X-axis, Y-axis, and Z-axis, respectively. A through hole or groove is provided at the center of each of the X-axis gyroscopes 2, Y-axis gyroscope 3, and Z-axis gyroscope 4, and an accelerometer 5 is mounted in the through hole or groove. Specifically, a gyroscope generally has a relatively large optical fiber ring with a central hole at its center. This space is generally not utilized. In this embodiment, this space is used as a space for mounting the accelerometer 5. The accelerometer 5 can be connected to the IMU bracket 1, directly to the inner wall of the central hole of the gyroscope, or configured as a groove in which the accelerometer 5 is mounted. The mounting method is selected so that the top surface of the accelerometer 5 is no higher than the top surface of the gyroscope, making the overall structure more compact. Furthermore, there is no need to design a separate bracket for the accelerometer 5, reducing design costs and making installation more convenient.

[0035] A plurality of arms 6 extending along the Y-axis are provided on two opposite side walls perpendicular to the X-axis, and shock absorbers 7 are installed on the arms 6. Specifically, the arm 6 is a plate-like structure perpendicular to the Z-axis; the shock absorber 7 is a cylindrical structure with its axis parallel to the Z-axis, and is installed on both sides of the arm 6 along the Z-axis. The shock absorber 7 includes a circular base, and a shock-absorbing rubber is provided at one end of the base, and the base is used to press the shock-absorbing rubber to make it fit with the arm 6. During installation, the arm 6 on the IMU bracket 1 is fixed to the box accommodating the inertial navigation measurement component by bolts, and at the same time, the base of the shock absorber 7 is pressed by bolts to make the shock-absorbing rubber fit with the arm 6, thereby playing a role in shock absorption and impact resistance. Shock-absorbing rubber is provided on both sides of the arm 6 to prevent rigid connection and have good impact and shock resistance.

[0036] To prevent interference between the support arms 6 and the gyroscope, circuit board assembly, and overall footprint, two support arms 6 are provided on each of two opposing sidewalls perpendicular to the X-axis. The support arms 6 on the same sidewall are located at opposite ends of the diagonal of that sidewall, with the diagonals corresponding to the two support arms 6 on that sidewall intersecting the diagonals corresponding to the two support arms 6 on the other sidewall. The side of the support arm 6 perpendicular to the X-axis and facing away from the IMU bracket is flush with the corresponding side of the IMU bracket 1.

[0037] The IMU bracket 1 has a cavity within it, within which a circuit board assembly is mounted. The X-axis gyroscope 2, Y-axis gyroscope 3, Z-axis gyroscope 4, and accelerometer 5 are all connected to this circuit board assembly. The circuit board assembly includes two opposing circuit board mounting brackets 8, which are mounted within the cavity of the IMU bracket 1. Multiple mounting slots are provided parallel to opposite sides of each of the two circuit board mounting brackets 8. A circuit board 9 is mounted between the two opposing mounting slots. The circuit board 9 is respectively connected to the X-axis gyroscope 2, Y-axis gyroscope 3, Z-axis gyroscope 4, and accelerometer 5. The circuit board assembly also includes a base plate 10, which is perpendicular to the circuit board 9 and is provided with multiple input interfaces 12 and corresponding output interfaces 11. The input interfaces 12 are respectively connected to each circuit board 9. The circuit board mounting brackets 8 are mounted on the inner sides of two opposing side walls of the IMU bracket 1 along the X-axis, and the circuit board 9 is positioned perpendicular to the Z-axis. A baseplate bracket 13 is also provided on the baseplate 10. This bracket is fixed to the open end of the IMU bracket 1 corresponding to the Y-axis. This allows for the circuit board mounting bracket 8 to function as a single unit, with each functional circuit board 9 mounted parallel to its respective mounting slots and output via a unified interface on the baseplate 10. This creates a more rational overall structure, facilitates wiring, and is more compact. Furthermore, the IMU bracket has two connected open ends to facilitate installation of the entire circuit board assembly, which is then secured by the circuit board mounting bracket 8 and baseplate bracket 13.

[0038] The harmonic response analysis of the three axes of the present invention is carried out below. The harmonic response is given by the following excitation conditions: frequency 5Hz-500Hz, acceleration amplitude 9800mm / s2 (1g). Sweep frequency analysis is performed along each axis to obtain the displacement variation trend of the navigation device along the three directions with frequency. Figure 4-Figure 6 shown.

[0039] The present invention performs random vibration analysis. Based on the usage status of the inertial navigation device, the excitation conditions of the external random vibration are given according to GJB150.16A-2009 Military Equipment Laboratory Environmental Test Method Part 16: Combined Wheel Vibration Environment C3 Spectrum in Vibration Test. Random vibration non-simulation analysis is performed in three directions respectively. The root mean square (RMS) value of the acceleration near the gyro installed on the inertial measurement unit bracket is monitored. Figure 7 As shown in the figure, it can be seen that after adopting the vibration reduction system, random vibration according to the C3 spectrum will have a certain vibration reduction effect. The vibration reduction effect along the Z-axis and X-axis is not very obvious, with the vibration reduction effects of 5.2% and 8.6% respectively. There is an obvious vibration reduction effect along the Y-axis, with the vibration reduction effect reaching 42.4%.

[0040] Random vibration analysis of the inertial measurement unit was performed. Based on the inertial navigation system's operating status, the excitation conditions for external random vibrations were determined according to GJB150.16A-2009, Military Equipment Laboratory Environmental Test Methods, Part 16: Narrowband Random Vibration D1 Spectrum for Tracked Vehicle Cargo Securement in Vibration Tests. Random vibration simulation analysis was performed in three directions. To simulate the 26km tracked vehicle transport environment, the random vibration process was divided into five test sections for each direction. To ensure that each section met the structural design requirements, the random vibration conditions in each section were simulated and analyzed separately.

[0041] Perform random vibration of D1 spectrum along the vertical direction, monitor the acceleration root mean square (RMS) value of the area near the gyro installed on the inertial measurement unit bracket, and compare the average value with the input RMS value to obtain the vibration reduction effect of the vibration reduction system, such as Figure 8 As shown in the figure, it can be found that except for the random vibration of group 4, which has an amplifying effect, the random vibrations of the other segmented groups have a vibration reduction effect. Through analysis of the results, it is found that the reason why the vibration reduction system has an amplifying effect is that the given narrow-band random vibration spectrum happens to be in the natural frequency region of the vertical vibration reduction system, which causes resonance and produces a resonance amplification effect, resulting in the amplification effect of the entire random vibration process.

[0042] Perform random vibration of D1 spectrum along the X direction and monitor the root mean square (RMS) value of acceleration in the area near the gyro where the inertial measurement unit bracket is installed, such as Figure 9 As shown, the average value is taken and compared with the input RMS value to obtain the vibration reduction effect of the vibration reduction system. In each random vibration segment, the vibration reduction system has both amplification and reduction effects. The reason for the amplification effect of the vibration reduction system is that the given narrow-band random vibration spectrum happens to be in the natural frequency region of the vertical vibration reduction system, causing resonance and a resonance amplification effect, resulting in the amplification effect of the entire random vibration process.

[0043] Perform random vibration of D1 spectrum along the Y direction and monitor the root mean square (RMS) value of acceleration in the area near the gyro where the inertial measurement unit bracket is installed, such as Figure 10 As shown, the average value is taken and compared with the input RMS value to obtain the vibration reduction effect of the vibration reduction system. In each section of random vibration, the vibration reduction system has an amplification effect and a vibration reduction effect. The reason why the vibration reduction system is in the amplification effect is that the given narrow-band random vibration spectrum is just in the natural frequency area of the vertical direction vibration reduction system, and a resonance phenomenon occurs, resulting in a resonance amplification effect, which causes the entire random vibration process to show an amplification effect.

[0044] The present invention integrates the entire inertial measurement unit (IMU) into a single unit and secures it to the device housing via screws. The accelerometer is placed within the fiber optic ring of the gyroscope to reduce its size. A vibration damper is mounted on the IMU's support arm, which is mounted in a four-point spatial arrangement. The vibration damping rubber is made of silicone rubber with a Shore hardness of 45 and a damping ratio between 0.12 and 0.18. Furthermore, the extension direction of each arm is restricted to align with the direction in which the fiber optic ring or circuit board assembly of each gyroscope extends. This results in a rectangular footprint for the entire IMU, eliminating any excess space and protruding parts. The circuit board is mounted on a circuit board mounting bracket, which is fastened to the interior of the IMU bracket. Data signals are extracted from the base plate of the mounting bracket. The overall structure is compact, with built-in vibration damping devices, and exhibits excellent miniaturization, impact resistance, and seismic resistance.

[0045] Although the embodiments of the present invention have been shown and described, it is apparent to those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and basis of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Therefore, the embodiments of the present invention are merely illustrative examples of the present invention. No matter from which point of view, the embodiments of the present invention do not constitute a limitation on the present invention.

Claims

1. An inertial navigation measurement assembly, characterized in that: An IMU bracket having a rectangular box structure, wherein two adjacent sides of the IMU bracket are open ends, a Z axis is defined to be perpendicular to a plane where one of the open ends is located, a Y axis is defined to be perpendicular to a plane where the other open end is located, and an X axis is perpendicular to the Y axis and the Z axis; An X-axis gyroscope, a Y-axis gyroscope, and a Z-axis gyroscope are respectively installed on three adjacent side walls of the IMU bracket corresponding to the X-axis, Y-axis, and Z-axis, and a through hole or groove is opened at the center of the X-axis gyroscope, the Y-axis gyroscope, and the Z-axis gyroscope, and an accelerometer is installed in the through hole or groove; A plurality of supporting arms extending along the Y-axis are provided on two opposite side walls perpendicular to the X-axis, and shock absorbers are installed on the supporting arms; A cavity is provided inside the IMU bracket, a circuit board assembly is installed in the cavity, and the X-axis gyroscope, Y-axis gyroscope, Z-axis gyroscope and accelerometer are all connected to the circuit board assembly.

2. An inertial navigation measurement assembly according to claim 1, characterized in that: The support arm is a plate-like structure perpendicular to the Z axis; the shock absorber is a cylindrical structure with its axis parallel to the Z axis and is installed on both sides of the support arm along the Z axis.

3. An inertial navigation measurement assembly according to claim 2, characterized in that: The shock absorber comprises a circular base, one end of which is provided with a shock-absorbing rubber, and the base is used for pressing the shock-absorbing rubber to make it fit with the support arm.

4. The inertial navigation measurement assembly according to claim 1, characterized in that: Two of the arms are provided on each of the two opposite side walls perpendicular to the X-axis, and the arms on the same side wall are located at both ends of the diagonal of the side wall, and the diagonals corresponding to the two arms on the side wall are arranged to intersect with the diagonals corresponding to the two arms on the other side wall.

5. The inertial navigation measurement assembly according to claim 1, characterized in that: The support arm is perpendicular to the X-axis and the side surface facing away from the IUM support is flush with the corresponding side surface of the IMU support.

6. The inertial navigation measurement assembly according to claim 1, characterized in that: The top surfaces of the X-axis gyroscope, the Y-axis gyroscope, and the Z-axis gyroscope are not lower than the top surfaces of the corresponding accelerometers.

7. The inertial navigation measurement assembly according to claim 1, characterized in that: The circuit board assembly includes two oppositely arranged circuit board mounting brackets, which are installed in the cavity of the IMU bracket; multiple mounting slots are arranged in parallel on opposite sides of the two circuit board mounting brackets, and a circuit board is installed between the two opposite mounting slots. The circuit board is respectively connected to the X-axis gyroscope, Y-axis gyroscope, Z-axis gyroscope and accelerometer.

8. An inertial navigation measurement assembly according to claim 7, characterized in that: The circuit board assembly further comprises a base plate, which is perpendicular to the circuit board and is provided with a plurality of input interfaces and corresponding output interfaces, wherein the input interfaces are respectively connected to each circuit board.

9. The inertial navigation measurement assembly according to claim 7, characterized in that: The circuit board mounting bracket is installed on the inner sides of two opposite side walls of the IMU bracket along the X-axis direction, and the circuit board is arranged perpendicular to the Z-axis.

10. The inertial navigation measurement assembly according to claim 8, characterized in that: A base plate bracket is also provided on the base plate, and the base plate bracket is fixed on the end surface of the open end of the IMU bracket corresponding to the Y-axis.

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