An integrated inertial measurement module and inertial measurement unit

Abstract

The present invention discloses an integrated inertial measurement module and inertial measurement unit, the module comprising: a base, a housing, a top cover, a quartz accelerometer, a fiber optic ring, a fiber optic gyroscope assembly, and a circuit board; the base, housing, and top cover cooperate to form a confined space; the quartz accelerometer, fiber optic ring, fiber optic gyroscope assembly, and circuit board are all located within the confined space; wherein the fiber optic ring is fixedly mounted in the middle of the base; the quartz accelerometer is mounted on the inner central axis of the fiber optic ring so that the measurement axis of the quartz accelerometer coincides with the central axis of the fiber optic ring. The present invention places the quartz accelerometer inside the fiber optic ring, reducing the size of the inertial measurement module; more importantly, the fiber optic ring and the accelerometer are coaxial, which helps eliminate the influence of the lever arm on the measurement accuracy of the quartz accelerometer, improves the measurement accuracy of the inertial measurement module and unit, and has good market application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of inertial measurement, and in particular relates to an integrated inertial measurement module and an inertial measurement unit. Background Art

[0002] Inertial measurement units are mainly used to measure the acceleration and angular velocity information of the carrier in real time to determine the carrier's speed, position and attitude. They are currently widely used in military fields such as submarines, ships, missiles and various military aircraft, as well as many civilian fields such as ship navigation, ocean development, geodesy, oil drilling, drones, etc.

[0003] The inertial measurement unit (IMU) consists of three gyroscopes, three accelerometers, and an I / F conversion module. The three gyroscopes provide angular velocity information in three directions of the carrier's motion; the three accelerometers measure the carrier's linear motion in three directions and output current signals; and the I / F conversion module converts the current signals output by the three accelerometers into pulse counts. Together, the accelerometers and I / F conversion module measure and collect carrier acceleration information.

[0004] The inertial measurement unit installs three gyroscopes and three accelerometers orthogonally, with one gyroscope and one accelerometer installed on each sensitive axis. Figure 1 Ideally, the measurement axes of the three gyroscopes and three accelerometers converge to the center of gravity of the measurement system.

[0005] However, in the actual structural design process, it is difficult to achieve ideal conditions for the installation positions of the gyroscopes and accelerometers, and the intersection points of the three gyroscope and three accelerometer measurement axes cannot converge to the center of gravity of the measurement unit. Figure 2 As shown, at this time, the line vectors from the center of gravity of the measurement unit to the measurement points of each accelerometer (gyroscope) form a set of lever arms. The carrier coordinate system with the center of gravity of the measurement unit as the origin can be regarded as a rigid body, and the angular velocity of each point on it is exactly the same. Therefore, the lever arm has no effect on the gyroscope measurement output. However, due to the influence of rotation, the forces at each point in the carrier coordinate system space are generally different, indicating that the lever arm formed by the line vectors from the origin of the coordinate system to the accelerometer measurement point has an impact on the accelerometer measurement value. Accelerometer measurement point specific force Compare with the coordinate origin The relationship is:

[0006]

[0007] in, and They represent the tangential acceleration and normal acceleration of the accelerometer measurement point relative to the origin of the coordinate system, respectively. It can be seen that the lever arm affects the accelerometer's measurement accuracy, especially under high dynamic conditions.

[0008] In addition, since the center of the fiber optic gyroscope is hollow and the spatial structure is not reasonably planned and utilized, the inertial measurement unit composed of the orthogonal installation of the gyroscope and accelerometer is still relatively large, resulting in the aforementioned measurement unit having a weak advantage in miniaturized application requirements.

[0009] Therefore, there is an urgent need in this field to design an inertial measurement unit with a new structure, small size and high accelerometer accuracy. Summary of the Invention

[0010] The purpose of the present invention is to provide an integrated inertial measurement module and an inertial measurement unit to solve the problems of insufficient measurement accuracy of accelerometers in existing inertial measurement units and weak advantages in miniaturized application requirements.

[0011] To solve the above technical problems, the present invention first provides an integrated inertial measurement module, which includes: a base, a housing, a top cover, a quartz accelerometer, a fiber optic ring, a fiber optic gyroscope assembly, and a circuit board; the base, housing, and top cover are arranged in conjunction with each other to form a confined space; the quartz accelerometer, fiber optic ring, fiber optic gyroscope assembly, and circuit board are all located in the confined space;

[0012] Wherein, the optical fiber ring is fixedly installed in the middle position of the base;

[0013] The quartz accelerometer is installed at the inner central axis of the optical fiber ring so that the measuring axis of the quartz accelerometer coincides with the central axis of the optical fiber ring;

[0014] The fiber optic gyroscope assembly is installed on the outside of the fiber optic ring;

[0015] The circuit board is installed above the optical fiber ring and the quartz accelerometer, and the circuit board is connected to the quartz accelerometer, the optical fiber ring, and the optical fiber gyroscope assembly through a signal line.

[0016] Preferably, an inner shell is installed inside the optical fiber ring and outside the quartz accelerometer.

[0017] Preferably, the circuit board is a gyro control and I / F conversion integrated circuit board.

[0018] Preferably, the shell is cylindrical or nearly cylindrical.

[0019] Preferably, the fiber optic gyroscope assembly includes: a light source, a coupler, a detector, an integrated optical device, etc.

[0020] Preferably, the circuit board is fixedly mounted to the housing by screws; the quartz accelerometer, the optical fiber ring, and the optical fiber gyroscope assembly are fixedly mounted to the base by screws, respectively.

[0021] Preferably, the top cover is provided with an interface for installing a connector to externally transmit the data measured by the measurement module.

[0022] Another aspect of the present invention provides an inertial measurement unit, comprising three integrated inertial measurement modules as described above; the three integrated inertial measurement modules are arranged in a spatially orthogonal arrangement.

[0023] Preferably, the three integrated inertial measurement modules are reasonably weighted to ensure that the intersection of the accelerometer measurement axes coincides with the far point of the carrier coordinate system, thereby improving the measurement accuracy of the accelerometer.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention provides an integrated inertial measurement module. This module rationally utilizes the space inside the gyro fiber ring and places a quartz accelerometer inside the fiber ring. Compared with traditional solutions, this saves accelerometer space and reduces the size of the inertial measurement module. More importantly, the inertial module provided by the present invention makes the fiber ring and accelerometer coaxial, which helps eliminate the influence of the lever arm on the measurement accuracy of the quartz accelerometer, thereby improving the measurement accuracy of the inertial measurement module and unit.

[0026] 2. This invention integrates the gyro control circuit with the I / F conversion circuit. This, on the one hand, saves space around the fiber optic ring, providing room for the accelerometer to be placed in the center of the gyro. On the other hand, from the perspective of the inertial measurement module, two circuit boards are reduced to one, saving space and reducing the size. Furthermore, the measurement unit composed of three new inertial measurement modules requires only three connectors, while traditional solutions require seven.

[0027] 3. The integrated inertial measurement module and inertial measurement unit provided by the present invention have the advantages of small size, high dynamic test accuracy, low cost, etc., and have good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the installation of a gyroscope and an accelerometer in the prior art.

[0029] Figure 2 The figure is a schematic diagram of the installation position and lever arm of the accelerometer in the prior art.

[0030] Figure 3 Schematic diagram of the integrated inertial measurement module of the present invention.

[0031] Figure ID:

[0032] Base 1, outer shell 2, top cover 3, quartz accelerometer 4, optical fiber ring 5, circuit board 6, inner shell 7. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "two ends", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0035] In the present invention, unless otherwise clearly stipulated and limited, the terms "installation", "setting", "connection", "fixation" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0036] Please see the attached Figure 3 To solve the above technical problems, the present invention provides a technical solution: an integrated inertial measurement module, comprising: a base 1, a housing 2, a top cover 3, a quartz accelerometer 4, a fiber optic ring 5, a fiber optic gyroscope assembly, and a circuit board 6; the base 1, housing 2, and top cover 3 are arranged in conjunction with each other to form a confined space; the quartz accelerometer 4, fiber optic ring 5, fiber optic gyroscope assembly, and circuit board 6 are all located in the confined space;

[0037] Wherein, the optical fiber ring 5 is fixedly installed in the middle position of the base 1;

[0038] The quartz accelerometer 4 is mounted on the central axis inside the fiber ring 5, so that its measurement axis coincides with the central axis of the fiber ring 5. This coaxial design eliminates the lever arm, minimizing its impact on the measurement accuracy of the quartz accelerometer 4. Furthermore, mounting the quartz accelerometer 4 inside the fiber ring 5 effectively utilizes the space inside the fiber ring 5, eliminating the need for additional space for an accelerometer. This reduces the size of the inertial measurement module and unit, enhancing the application prospects and advantages of inertial measurement units in miniaturized applications.

[0039] In some embodiments, an inner shell 7 is installed inside the optical fiber ring 5 and outside the quartz accelerometer 4. The installation of the inner shell 7 is beneficial for avoiding possible signal interference between the optical fiber ring 5 and the quartz accelerometer 4, and is beneficial for fixing and maintaining the overall shape of the optical fiber ring 5.

[0040] The fiber optic gyroscope assembly (not shown in the figure) is evenly installed around the fiber optic ring 5;

[0041] The circuit board 6 is installed above the optical fiber ring 5 and the quartz accelerometer 4. The circuit board 6 is connected to the quartz accelerometer, the optical fiber ring, and the optical fiber gyroscope assembly through signal lines.

[0042] In some embodiments, the circuit board 6 is a gyro control and I / F conversion integrated circuit board, which integrates the gyro control circuit and the I / F conversion circuit. On the one hand, it saves space around the fiber optic gyroscope assembly and provides space for the quartz accelerometer 4 to be placed inside the fiber optic ring 5. On the other hand, the number of circuit boards is reduced, which is conducive to reducing the volume of the inertial measurement module and reducing the number of interfaces.

[0043] In some embodiments, the housing 2 is cylindrical or nearly cylindrical.

[0044] In some embodiments, the fiber optic gyroscope assembly includes: a light source, a coupler, a detector, and an integrated optical device.

[0045] In some embodiments, the circuit board 6 is fixedly mounted to the housing 2 by a plurality of screws; the quartz accelerometer 4, the optical fiber ring 5, and the optical fiber gyroscope assembly are fixedly mounted to the base 1 by a plurality of screws.

[0046] Preferably, the top cover 3 is provided with an interface for installing a connector to externally transmit the data measured by the integrated inertial measurement module.

[0047] Based on the aforementioned integrated inertial measurement module, the present invention further provides an inertial measurement unit, which includes three integrated inertial measurement modules according to any of the aforementioned embodiments; the three integrated inertial measurement modules are arranged in a spatially orthogonal arrangement.

[0048] In some embodiments, the three integrated inertial measurement modules are properly weighted. After proper weighting, it is possible to ensure that the intersection of the quartz accelerometer measurement axes coincides with the origin of the carrier coordinate system. In this case, the arm from the origin to the intersection of the accelerometer measurement axes satisfies:

[0049]

[0050] Substituting (2) into (1) we can get:

[0051]

[0052] It can be seen that the quartz accelerometer is not affected by the lever arm at this time, thereby improving the measurement accuracy of the quartz accelerometer in the inertial measurement unit.

[0053] In summary, the present invention provides an integrated inertial measurement module and inertial measurement unit. This inertial measurement module rationally utilizes the space vacated inside the gyroscopic fiber ring, placing a quartz accelerometer inside the fiber ring. Compared with traditional solutions, this saves space for the accelerometer and reduces the size of the inertial measurement module. More importantly, the inertial module provided by the present invention places the fiber ring and accelerometer coaxially, which helps eliminate the influence of the lever arm on the measurement accuracy of the quartz accelerometer and improves the measurement accuracy of the inertial measurement module and unit. The integrated inertial measurement module and inertial measurement unit provided by the present invention have the advantages of small size, high dynamic test accuracy, and low cost, and have good market application prospects.

[0054] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An integrated inertial measurement module, characterized in that: The module includes: a base, a housing, a top cover, a quartz accelerometer, a fiber optic ring, a fiber optic gyroscope assembly, and a circuit board; the base, the housing, and the top cover are arranged in conjunction with each other to form a confined space; the quartz accelerometer, the fiber optic ring, the fiber optic gyroscope assembly, and the circuit board are all located in the confined space; Wherein, the optical fiber ring is fixedly installed in the middle position of the base; The quartz accelerometer is installed at the inner central axis of the optical fiber ring so that the measuring axis of the quartz accelerometer coincides with the central axis of the optical fiber ring; The fiber optic gyroscope assembly is installed on the outside of the fiber optic ring; The circuit board is installed above the optical fiber ring and the quartz accelerometer, and the circuit board is connected to the quartz accelerometer, the optical fiber ring, and the optical fiber gyroscope assembly through a signal line.

2. The integrated inertial measurement module according to claim 1, wherein: An inner shell is installed on the inner side of the optical fiber ring and the outer side of the quartz accelerometer.

3. The integrated inertial measurement module according to claim 1, wherein: The circuit board is a gyro control and I / F conversion integrated circuit board.

4. The integrated inertial measurement module according to claim 1, wherein: The shell is cylindrical or nearly cylindrical.

5. The integrated inertial measurement module according to claim 1, wherein: The fiber optic gyroscope assembly includes: a light source, a coupler, a detector, and an integrated optical device.

6. The integrated inertial measurement module according to claim 1, wherein: The circuit board is fixedly mounted to the housing via screws; the quartz accelerometer, the optical fiber ring, and the optical fiber gyroscope assembly are fixedly mounted to the base via screws respectively.

7. The integrated inertial measurement module according to claim 1, wherein: The top cover is provided with an interface for installing a connector to externally transmit the data measured by the measurement module.

8. An inertial measurement unit, characterized in that The measurement unit includes three integrated inertial measurement modules according to any one of claims 1 to 7.

9. The inertial measurement unit according to claim 8, wherein The three integrated inertial measurement modules are arranged in a spatially orthogonal arrangement.

10. The inertial measurement unit according to claim 8, wherein The three integrated inertial measurement modules are reasonably weighted to ensure that the intersection of the accelerometer measurement axes coincides with the far point of the carrier coordinate system, thereby improving the measurement accuracy of the accelerometer.

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