Inertial measurement unit and navigation system
By using a flexible circuit board and a symmetrical three-dimensional layout for the inertial measurement unit (IMU) design, the problems of redundant volume and complex assembly of traditional IMUs are solved. This results in a smaller, more integrated, and more precise inertial measurement unit that can adapt to a wide range of temperature and environmental changes and improves its resistance to vibration and shock.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING WEIYUAN TIMES TECH CO LTD
- Filing Date
- 2025-09-24
- Publication Date
- 2026-07-21
Smart Images
Figure CN224535110U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of navigation, guidance and control technology, and in particular to an inertial measurement unit and navigation system. Background Technology
[0002] As the core component for motion sensing and attitude calculation, the performance of the inertial measurement unit (IMU) depends not only on the signal-to-noise ratio and zero-bias stability of the MEMS (Micro-Electro-Mechanical System) sensor itself, but also closely on the symmetry and stability of the overall mechanical structure and the alignment accuracy of the axes between sensors. From a measurement principle perspective, the accelerometer needs to achieve strict orthogonality of its three sensing axes, converging at a single point. The gyroscope should also meet similar geometric constraints and remain parallel to the corresponding axis of the accelerometer, thereby minimizing non-orthogonal errors and additional measurement deviations caused by lever effects. Existing miniature IMUs mostly use traditional orthogonal mechanical architectures, employing high-precision machined polyhedral supports to achieve sensor spatial arrangement. While this type of structure easily ensures installation orthogonality, it inherently suffers from problems such as volume redundancy, structural asymmetry, a large number of parts, and high assembly complexity. Furthermore, rigid mechanical connections easily introduce assembly stress and thermal mismatch, leading to micro-deformation of the structure under temperature changes or mechanical vibration, which in turn interferes with the weak output signal of the MEMS sensor, limiting its performance and application range in practical miniature platforms.
[0003] Therefore, there is an urgent need for an inertial measurement unit and navigation system to solve the aforementioned technical problems. Utility Model Content
[0004] The purpose of this invention is to provide an inertial measurement unit and navigation system to solve the problems existing in the prior art, thereby achieving higher integration, wider application range, and higher measurement accuracy.
[0005] To achieve the above objectives, this utility model provides the following solution: This invention provides an inertial measurement unit (IMU) comprising a signal processing circuit board, a housing, a base, at least three gyroscope assemblies, and at least three accelerometer assemblies. The signal processing circuit board is parallel to and fixedly mounted on the base. The three gyroscope assemblies are designated as a first gyroscope assembly, a second gyroscope assembly, and a third gyroscope assembly. The first accelerometer assembly, the second accelerometer assembly, the first gyroscope assembly, and the second gyroscope assembly are sequentially distributed around the circumference of the signal processing circuit board and are all perpendicular to the circuit board, and are all fixedly connected to the base. The third gyroscope assembly and the third accelerometer assembly are parallel to and below the signal processing circuit board and fixedly mounted on the base. The first accelerometer assembly, the second accelerometer assembly, the first gyroscope assembly, and the second gyroscope assembly are all connected to the signal processing circuit board via a flexible circuit board. The third gyroscope assembly and the third accelerometer assembly are connected to either the first gyroscope assembly or the second gyroscope assembly via a flexible circuit board.
[0006] In some embodiments, the first accelerometer assembly includes a first accelerometer and a first accelerometer circuit board, with the first accelerometer fixedly disposed outside the first accelerometer circuit board; the second accelerometer assembly includes a second accelerometer and a second accelerometer circuit board, with the second accelerometer fixedly disposed outside the second accelerometer circuit board; the first gyroscope assembly includes a first gyroscope and a first gyroscope circuit board, with the first gyroscope fixedly disposed outside the first gyroscope circuit board; the second gyroscope assembly includes a second gyroscope and a second gyroscope circuit board, with the second gyroscope fixedly disposed outside the second gyroscope circuit board; the third gyroscope assembly includes a third gyroscope; the third accelerometer assembly includes a third accelerometer; and the third gyroscope and the third accelerometer share a common circuit board.
[0007] In some embodiments, the base is a rigid metal base.
[0008] In some embodiments, the base includes a base plate and a fixing seat, the fixing seat is fixedly disposed on the base plate, the base plate is used to be fixedly connected to the outer shell, the fixing seat has a receiving groove in the middle, the third accelerometer is fixedly disposed below the main circuit board, the third gyroscope is fixedly disposed above the main circuit board, the receiving groove is used to accommodate the third accelerometer, and the main circuit board is fixedly connected to the upper surface of the fixing seat.
[0009] In some embodiments, the base further includes a plurality of fixing posts, which are distributed circumferentially around the fixing seat and are vertically and fixedly connected to the base plate.
[0010] In some embodiments, a pressure plate is also included. The pressure plate includes a fixing part, a first fitting part, and a second fitting part. The first fitting part and the second fitting part are respectively fixedly connected to both ends of the fixing part, and both the first fitting part and the second fitting part have an angle with the fixing part. Four fixing posts are provided. The fixing base is square, and the four fixing posts are respectively fixedly provided at the four corners of the fixing base. The fixing part is connected to the side of the fixing post by fasteners. The first fitting part is used to fit onto the accelerometer circuit board, and the second fitting part is used to fit onto the gyroscope circuit board adjacent to the accelerometer circuit board. The pressure plate can lock an accelerometer circuit board and an adjacent gyroscope circuit board together onto the base.
[0011] In some embodiments, the fastener is a first bolt, the fixing post is provided with a first threaded hole, the first bolt can be threadedly connected to the first threaded hole, and the nut of the first bolt can abut against the side of the pressure plate away from the fixing post.
[0012] In some embodiments, flexible thermal pads are laid between the first accelerometer circuit board, the second accelerometer circuit board, the first gyroscope circuit board, the second gyroscope circuit board, and the main circuit board and the base.
[0013] In some embodiments, the base has multiple heat-conducting grooves, and the heat-conducting grooves are filled with heat-conducting material.
[0014] This utility model also provides a navigation system, including the inertial measurement unit as described above, wherein the centroid of the inertial measurement unit coincides with the geometric center.
[0015] The present invention achieves the following technical advantages over the prior art: The inertial measurement unit provided by this utility model has a first accelerometer, a second accelerometer, a first gyroscope, and a second gyroscope vertically distributed around the signal processing circuit board, while the third gyroscope and the third accelerometer are placed parallel to each other under the board. This makes full use of the horizontal and vertical three-dimensional space, avoids the area waste of traditional planar layouts, and achieves a smaller overall volume with the same performance. It is more suitable for scenarios with strict installation space requirements (such as drones, micro robots, and wearable devices) and has a high degree of integration.
[0016] Traditional rigid circuit boards (PCBs) are connected by metal pins or connectors. When subjected to temperature changes, the difference in the coefficients of thermal expansion of different materials (such as PCB substrate and metal pins) can cause stress deformation at the connection points, or even poor contact, affecting the stability of signal transmission. Flexible circuit boards, on the other hand, are made of soft materials with good thermal stability, can adapt to the slight deformation caused by temperature fluctuations, and have a stable signal transmission path. They can effectively reduce the interference of high and low temperature environments on the data interaction between sensors and signal processing boards, ensuring normal operation in industrial-grade (-40℃~85℃) or even harsher temperature scenarios, and have a wide range of applications.
[0017] The first accelerometer, second accelerometer, first gyroscope, and second gyroscope are sequentially distributed along the circumference of the signal processing circuit board, forming a symmetrical installation layout. This effectively offsets installation errors caused by structural asymmetry (such as sensor axis misalignment) and environmental interference errors (such as the uneven transmission of vibration and impact on the asymmetrical structure), ensuring the consistency of measurement references for each axis sensor. The design strictly ensures that the center of mass of the inertial measurement unit (IMU) is aligned with its geometric center, avoiding dynamic errors caused by center of mass misalignment. When the IMU moves with the carrier (such as rotating or accelerating), center of mass misalignment generates additional inertial forces or torques, interfering with the gyroscope's measurement of angles and angular velocities, and the accelerometer's measurement of linear acceleration. Alignment of the center of mass with the geometric center completely eliminates this additional interference, significantly improving measurement accuracy under dynamic conditions (such as high-precision navigation and attitude control scenarios). The four vertically mounted components (first accelerometer, second accelerometer, first gyroscope, and second gyroscope) are simultaneously fixedly connected to the base, and the two parallel mounted components (third gyroscope and third accelerometer) are also fixed to the base. All core functional components are directly and rigidly fixed to the base, rather than relying solely on the support of the signal processing circuit board. This significantly improves the overall structure's resistance to vibration and impact, avoiding measurement failures caused by component loosening in high-frequency vibration or severe impact scenarios (such as automotive and aerospace applications). Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is an exploded view of the inertial measurement unit in some embodiments of this utility model; Figure 2 This is a schematic diagram showing the configuration of the gyroscope and accelerometer in some embodiments of this utility model; Figure 3This is a schematic diagram of the signal processing circuit board in some embodiments of the present invention; Figure 4 This is a schematic diagram of the structure of the accelerometer circuit board or gyroscope circuit board in some embodiments of this utility model; Figure 5 This is a schematic diagram of the overall circuit board structure in some embodiments of this utility model; Figure 6 This is a schematic diagram of the structure of the pressure plate fixing the gyroscope circuit board and the accelerometer circuit board in some embodiments of this utility model; Figure 7 It is a stress distribution diagram obtained from simulation of a circuit board fixed with screws; Figure 8 It is a stress distribution diagram obtained from simulation of a circuit board fixed by a pressure plate structure.
[0020] In the diagram: 1-Outer casing; 2-Wire hole; 3-First accelerometer circuit board; 4-First accelerometer; 5-Second accelerometer circuit board; 6-Second accelerometer; 7-First gyroscope circuit board; 8-First gyroscope; 9-Second gyroscope circuit board; 10-Second gyroscope; 11-Third accelerometer; 12-Main circuit board; 13-Third gyroscope; 14-Fixing base; 141-Receiving slot; 15-Fixing post; 16-Base plate; 17-Pressure plate; 171-Fixing part; 172-First bonding part; 173-Second bonding part; 18-First bolt; 19-Flexible circuit board; 20-Second bolt; 21-Signal processing circuit board; 22-Third bolt; 23-Hosting slot. Detailed Implementation
[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0022] The purpose of this invention is to provide an inertial measurement unit and navigation system to solve the problems existing in the prior art, thereby achieving higher integration, wider application range, and higher measurement accuracy.
[0023] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0024] Example 1 like Figures 1-8As shown, this utility model provides an inertial measurement unit, including a signal processing circuit board 21, a housing 1, a base, at least three gyroscope components, and at least three accelerometer components. The signal processing circuit board 21 is parallel to the base and fixedly mounted on it. The three gyroscope components are a first gyroscope component, a second gyroscope component, and a third gyroscope component. The three accelerometer components are a first accelerometer component, a second accelerometer component, and a third accelerometer component. The first accelerometer component, the second accelerometer component, the first gyroscope component, and the second gyroscope component are sequentially distributed within the signal processing circuit. The circumference of the board 21 is perpendicular to the signal processing circuit board 21 and is fixedly connected to the base. The third gyroscope assembly and the third accelerometer assembly are arranged parallel to each other below the signal processing circuit board 21 and fixed to the base. The first accelerometer assembly, the second accelerometer assembly, the first gyroscope assembly and the second gyroscope assembly are all connected to the signal processing circuit board 21 through the flexible circuit board 19. The third gyroscope assembly and the third accelerometer assembly are connected to the first gyroscope assembly or the second gyroscope assembly through the flexible circuit board 19. Moreover, the design ensures that the center of mass of the inertial measurement unit coincides with the geometric center.
[0025] The first accelerometer 4, the second accelerometer 6, the first gyroscope 8, and the second gyroscope 10 are vertically distributed around the signal processing circuit board 21. The third gyroscope 13 and the third accelerometer 11 are placed parallel to each other under the board. This makes full use of the horizontal and vertical three-dimensional space, avoids the area waste of traditional planar layouts, and achieves a smaller overall volume with the same performance. It is more suitable for scenarios with strict installation space requirements (such as drones, micro robots, and wearable devices) and has a high degree of integration.
[0026] Traditional rigid circuit boards (PCBs) are connected by metal pins or connectors. When subjected to temperature changes, the difference in the coefficients of thermal expansion of different materials (such as PCB substrate and metal pins) can cause stress deformation at the connection points, or even poor contact, affecting the stability of signal transmission. Flexible circuit boards are made of soft material with good thermal stability, which can adapt to the slight deformation caused by temperature fluctuations. Moreover, their own signal transmission path is stable, which can effectively reduce the interference of high and low temperature environments on the data interaction between sensors and signal processing boards, ensuring normal operation in industrial-grade (-40℃~85℃) or even harsher temperature scenarios. They have a wide range of applications.
[0027] The first accelerometer 4, the second accelerometer 6, the first gyroscope 8, and the second gyroscope 10 are sequentially distributed along the circumference of the signal processing circuit board 21, forming a symmetrical installation layout. This effectively offsets installation errors caused by structural asymmetry (such as sensor axis misalignment) and environmental interference errors (such as the uneven transmission of vibration and impact on the asymmetrical structure), ensuring the consistency of the measurement reference of each axis sensor. The design strictly ensures that the center of mass of the inertial measurement unit (IMU) is aligned with its geometric center, avoiding dynamic errors caused by center of mass misalignment. When the IMU moves with the carrier (such as rotating or accelerating), center of mass misalignment generates additional inertial forces or torques, interfering with the gyroscope's measurement of angles and angular velocities, and the accelerometer's measurement of linear acceleration. Alignment of the center of mass with the geometric center completely eliminates this additional interference, significantly improving measurement accuracy under dynamic conditions (such as high-precision navigation and attitude control scenarios). The four vertically mounted components (first accelerometer, second accelerometer, first gyroscope, and second gyroscope) are simultaneously fixedly connected to the base, and the two parallel mounted components (third gyroscope and third accelerometer) are also fixed to the base. All core functional components are directly and rigidly fixed to the base, rather than relying solely on the support of the signal processing circuit board 21. This significantly improves the overall structure's resistance to vibration and impact, and avoids measurement failures caused by component loosening in high-frequency vibration or severe impact scenarios (such as automotive and aerospace applications).
[0028] It should be noted that the top of the outer casing 1 is provided with lead holes, and various signal lines are soldered on the signal processing circuit board 21. The signal lines can pass through the lead holes 2 to electrically connect to external devices. The signal processing circuit board 21 adopts a multi-layer board design and integrates a high-performance processor, an analog-to-digital converter (ADC), a power management module, and a communication interface.
[0029] In some embodiments, the first accelerometer assembly includes a first accelerometer 4 and a first accelerometer circuit board 3, with the first accelerometer 4 fixedly disposed on the outside of the first accelerometer circuit board 3. The second accelerometer assembly includes a second accelerometer 6 and a second accelerometer circuit board 5, with the second accelerometer 6 fixedly disposed on the outside of the second accelerometer circuit board 5. The first gyroscope assembly includes a first gyroscope 8 and a first gyroscope circuit board 7, with the first gyroscope 8 fixedly disposed on the outside of the first gyroscope circuit board 7. The second gyroscope assembly includes a second gyroscope 10 and a second gyroscope circuit board 9, with the second gyroscope 10 fixedly disposed on the outside of the second gyroscope circuit board 9. The third gyroscope assembly includes a third gyroscope 13. The third accelerometer assembly includes a third accelerometer 11, with the third gyroscope 13 and the third accelerometer 11 sharing a common circuit board 12. The first accelerometer 4, the second accelerometer 6, the first gyroscope 8, and the second gyroscope 10 are respectively fixed on the outside of their respective circuit boards. This design makes the installation of these components more convenient and allows for clear determination of the installation position and orientation. Meanwhile, during maintenance and replacement, individual components and their circuit boards can be easily disassembled for inspection, repair, or replacement without significantly affecting other components. Placing the accelerometer and gyroscope on separate circuit boards, with some components distributed circumferentially around the signal processing circuit board 21, helps reduce electromagnetic interference between different types of sensors. The accelerometer primarily measures linear acceleration, while the gyroscope primarily measures angular velocity. Their operating principles and signal characteristics differ; separating them reduces signal coupling and improves measurement accuracy. The third gyroscope and the third accelerometer share a single circuit board 12, reducing the number of circuit boards used compared to equipping each sensor with a separate complete circuit board, thus lowering costs. It also reduces the number of connection lines and interfaces between circuit boards, simplifying circuit design and assembly processes, and reducing system complexity and failure rate. It should be noted that the three gyroscopes and three accelerometers are arranged as close as possible around the signal processing circuit board 21 to reduce lever arm effects during measurement.
[0030] It should be noted that mounting slots 23 are provided on the accelerometer circuit board, the gyroscope circuit board, and the main circuit board. The mounting slot 23 on the accelerometer circuit board is used to accommodate part of the main body of the accelerometer (first accelerometer 4 or second accelerometer 6) and to lock and limit the accelerometer (first accelerometer 4 or second accelerometer 6). The mounting slot 23 on the gyroscope circuit board is used to accommodate part of the main body of the gyroscope (first gyroscope 8 or second gyroscope 10) and to lock and limit the gyroscope (first gyroscope 8 or second gyroscope 10). The mounting slot 23 above the main circuit board is used to accommodate part of the main body of the third gyroscope 13 and to lock and limit the third gyroscope 13.
[0031] In some embodiments, the base includes a base plate 16 and a mounting base 14. The mounting base 14 is fixedly mounted on the base plate 16, and the base plate 16 is used to fixally connect to the outer casing 1. A receiving groove 141 is provided in the middle of the mounting base 14. A third accelerometer 11 is fixedly mounted below the main circuit board 12, and a third gyroscope 13 is fixedly mounted above the main circuit board 12. The receiving groove 141 is used to accommodate the third accelerometer. The main circuit board 12 is fixedly connected to the upper surface of the mounting base 14. Specifically, a third threaded hole is provided on the upper surface of the mounting base 14, and the main circuit board 12 is connected to the upper surface of the mounting base 14 by a third bolt 22. By sinking the receiving groove 141 to store the components, the vertical space occupied by the base is greatly reduced. Combined with the previous layout of the circumferential vertical components, the miniaturization of the IMU is further realized, making it more suitable for height-sensitive scenarios (such as wearable devices and micro drones). The third accelerometer 11 is embedded in the receiving groove 141 of the fixed base 14. The four sides of the groove can form a physical barrier, which can prevent dust and moisture in the external environment from directly contacting the sensor (especially since the third accelerometer 11 is located inside the base, close to the bottom plate 16, and is easily affected by the bottom environment), reducing the impact of contaminants on the sensor accuracy. On the other hand, when the IMU is subjected to external impact or vibration, the side walls of the receiving groove 141 can buffer part of the impact force, preventing the third accelerometer 11 from being damaged by direct collision or violent shaking.
[0032] In some embodiments, the base further includes multiple fixing posts 15, which are distributed circumferentially around the fixing base 14 and vertically and fixedly connected to the base plate 16. The base is a rigid metal base. Aluminum alloy with a low coefficient of thermal expansion is preferably selected, with a maximum deformation of less than 2 μm in a temperature range of -40°C to 85°C and a natural frequency of over 2000 Hz, providing an extremely stable mounting reference for multiple components. It should be noted that the top of the fixing post 15 is provided with a second threaded hole, and the signal processing circuit board 21 is fixed to the top of the fixing post 15 by a second bolt 20.
[0033] In some embodiments, the inertial measurement unit further includes a pressure plate 17. The pressure plate 17 includes a fixing part 171, a first fitting part 172, and a second fitting part 173. The first fitting part 172 and the second fitting part 173 are respectively fixedly connected to the two ends of the fixing part 171, and both the first fitting part 172 and the second fitting part 173 have an angle with the fixing part 171. Four fixing posts 15 are provided. The fixing base 14 is square, and the four fixing posts 15 are respectively fixedly provided at the four corners of the fixing base 14. The fixing part 171 is connected to the side of the fixing post 15 by fasteners. The first fitting part 172 is used to fit onto the accelerometer circuit board, and the second fitting part 173 is used to fit onto the gyroscope circuit board adjacent to the accelerometer circuit board. The pressure plate 17 can lock an accelerometer circuit board and an adjacent gyroscope circuit board together onto the base. The pressure plate 17 is a fixing structure. This structure distributes the installation stress to the entire circuit board plane through large-area contact and uniform pressure. Comparative experiments show that, compared with the traditional screw fixing method, the pressure plate 17 structure reduces the maximum installation stress from 45MPa to below 5MPa, and the micro-deformation on the device surface is reduced from 4μm to an almost undetectable level. Simulation comparisons were conducted using finite element analysis (FEA). Figure 7 The figure shows the stress distribution cloud map under the traditional screw-fixed circuit board method used in the comparative example. As shown, the maximum stress is concentrated near the screw hole, and the maximum deformation transmitted to the device surface is 4μm. Figure 8 The diagram shows the stress distribution cloud map under the fixing method of the pressure plate 17 in this embodiment. It can be seen that the stress is uniformly distributed through the pressure plate 17, and no deformation occurs on the surface of the device. This comparative result fully demonstrates that the mounting structure of the pressure plate 17 in this embodiment can effectively avoid stress concentration, significantly reduce the adverse effects of the mounting force on the measurement accuracy of the inertial sensor, and thus improve the performance and stability of the entire measurement unit.
[0034] In some embodiments, the fastener is a first bolt 18, and the fixing post 15 is provided with a first threaded hole. The first bolt 18 can be threadedly connected to the first threaded hole, and the nut of the first bolt 18 can abut against the side of the pressure plate 17 away from the fixing post 15. The first bolt 18 and the first threaded hole of the fixing post 15 are connected by threads. Compared with connection methods such as snaps and rivets, threaded engagement has the advantages of self-locking and rigid locking: on the one hand, the meshing between the threads can form a stable force transmission path, which can firmly lock the pressure of the pressure plate 17 on the fixing post 15, and avoid the connection from loosening due to long-term vibration (such as the high-frequency vibration of the IMU in drones and vehicle scenarios); on the other hand, the pull-out force and shear force of the threaded connection are much higher than those of the non-threaded connection, which can withstand the long-term action force between the pressure plate 17 and the components (accelerometer circuit board, gyroscope circuit board), ensuring that the pressure plate 17 is always tightly attached to the circuit board, without warping or displacement, and maintaining the effect of uniform stress distribution.
[0035] In some embodiments, flexible thermally conductive pads are laid between the first accelerometer circuit board 3, the second accelerometer circuit board 5, the first gyroscope circuit board 7, the second gyroscope circuit board 9, and the total circuit board 12 and the base. The flexible thermally conductive pads can absorb these mechanical stresses through their own deformation. During installation, the pads are compressed, dispersing the local pressure on the circuit board; during vibration, the elasticity of the pads can buffer the relative impact between the circuit board and the base, avoiding physical damage caused by rigid collisions, while reducing the transmission of vibration to the circuit board, indirectly reducing the vibration noise of the sensor. Even with high processing precision of the base and circuit board, it is difficult to completely avoid surface flatness errors (such as height deviation of the fixing seat 14 on the base, slight warping of the circuit board). The flexibility of the flexible thermally conductive pads can adapt to small errors. Regardless of whether the mounting surface is absolutely flat, the pads can tightly fit the surface of the circuit board and the base, ensuring the integrity of the heat conduction path (no increase in thermal resistance due to local gaps) and avoiding local suspension caused by processing errors (suspended areas cannot dissipate heat and are prone to heat accumulation), ensuring consistent heat dissipation for each circuit board.
[0036] In some embodiments, the base has multiple heat-conducting grooves filled with thermally conductive material. The design of the heat-conducting grooves allows the thermally conductive material (such as high thermal conductivity silicone or thermal paste) to directly contact the heat dissipation points of the component: for example, if the base below the main circuit board 12 has heat-conducting grooves and is filled with thermally conductive material, the heat from the main circuit board 12 can be quickly transferred to other areas of the base through the flexible thermally conductive pad to the thermally conductive material, without having to pass through the base's metal substrate first and then diffuse, significantly shortening the heat transfer distance and ensuring good heat dissipation.
[0037] Example 2 This embodiment also provides a navigation system, including the inertial measurement unit (IMU) of Embodiment 1, wherein the center of mass of the IMU coincides with its geometric center. In this embodiment, the center of mass of the IMU coincides with its geometric center, and during integration, it is only necessary to align the geometric center of the IMU with the motion reference center of the carrier (such as the center of gravity of a vehicle or the fuselage center of a drone) to avoid additional installation offset errors.
[0038] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. An inertial measurement unit, characterized in that: The device includes a signal processing circuit board, a housing, a base, at least three gyroscope assemblies, and at least three accelerometer assemblies. The signal processing circuit board is parallel to the base and fixedly mounted on it. The three gyroscope assemblies are designated as a first gyroscope assembly, a second gyroscope assembly, and a third gyroscope assembly. The three accelerometer assemblies are also designated as a first accelerometer assembly, a second accelerometer assembly, and a third accelerometer assembly. The first accelerometer assembly, the second accelerometer assembly, the first gyroscope assembly, and the second gyroscope assembly are sequentially distributed around the circumference of the signal processing circuit board and are all perpendicular to the circuit board and fixedly connected to the base. The third gyroscope assembly and the third accelerometer assembly are parallel to each other below the signal processing circuit board and fixedly mounted on the base. The first accelerometer assembly, the second accelerometer assembly, the first gyroscope assembly, and the second gyroscope assembly are all connected to the signal processing circuit board via a flexible circuit board. The third gyroscope assembly and the third accelerometer assembly are connected to either the first gyroscope assembly or the second gyroscope assembly via a flexible circuit board.
2. The inertial measurement unit according to claim 1, characterized in that: The first accelerometer assembly includes a first accelerometer and a first accelerometer circuit board, with the first accelerometer fixedly disposed on the outside of the first accelerometer circuit board. The second accelerometer assembly includes a second accelerometer and a second accelerometer circuit board, with the second accelerometer fixedly disposed on the outside of the second accelerometer circuit board. The first gyroscope assembly includes a first gyroscope and a first gyroscope circuit board, with the first gyroscope fixedly disposed on the outside of the first gyroscope circuit board. The second gyroscope assembly includes a second gyroscope and a second gyroscope circuit board, with the second gyroscope fixedly disposed on the outside of the second gyroscope circuit board. The third gyroscope assembly includes a third gyroscope. The third accelerometer assembly includes a third accelerometer, and the third gyroscope and the third accelerometer share a common circuit board.
3. The inertial measurement unit according to claim 1, characterized in that: The base is a rigid metal base.
4. The inertial measurement unit according to claim 2, characterized in that: The base includes a base plate and a fixing seat. The fixing seat is fixedly disposed on the base plate. The base plate is used to fixally connect to the outer shell. A receiving groove is opened in the middle of the fixing seat. The third accelerometer is fixedly disposed below the main circuit board. The third gyroscope is fixedly disposed above the main circuit board. The receiving groove is used to accommodate the third accelerometer. The main circuit board is fixedly connected to the upper surface of the fixing seat.
5. The inertial measurement unit according to claim 4, characterized in that: The base also includes multiple fixing columns, which are distributed circumferentially around the fixing seat and are vertically and fixedly connected to the base plate.
6. The inertial measurement unit according to claim 5, characterized in that: It also includes a pressure plate, which includes a fixing part, a first fitting part, and a second fitting part. The first fitting part and the second fitting part are respectively fixedly connected to both ends of the fixing part, and both the first fitting part and the second fitting part have an angle with the fixing part. Four fixing posts are provided. The fixing base is square, and the four fixing posts are respectively fixedly provided at the four corners of the fixing base. The fixing part is connected to the side of the fixing post by fasteners. The first fitting part is used to fit onto the accelerometer circuit board, and the second fitting part is used to fit onto the gyroscope circuit board adjacent to the accelerometer circuit board. The pressure plate can lock an accelerometer circuit board and an adjacent gyroscope circuit board together onto the base.
7. The inertial measurement unit according to claim 6, characterized in that: The fastener is a first bolt, and the fixing post is provided with a first threaded hole. The first bolt can be threadedly connected to the first threaded hole, and the nut of the first bolt can abut against the side of the pressure plate away from the fixing post.
8. The inertial measurement unit according to claim 2, characterized in that: Flexible thermal pads are laid between the first accelerometer circuit board, the second accelerometer circuit board, the first gyroscope circuit board, the second gyroscope circuit board, and the main circuit board and the base.
9. The inertial measurement unit according to claim 1, characterized in that: The base has multiple heat-conducting grooves, and the heat-conducting grooves are filled with heat-conducting material.
10. A navigation system, characterized in that: It includes an inertial measurement unit as described in any one of claims 1-9, wherein the centroid of the inertial measurement unit coincides with its geometric center.