Inertial measurement device based on MEMS device
Through the combination of cavity design and miniaturized MEMS devices, the volume and weight problems of inertial measurement devices in the fields of land navigation and mine inclinometers are solved, high-reliability inertial measurement is achieved, and the accuracy of navigation solutions and the zero-bias error compensation effect are improved.
Patent Information
- Application Number
- CN202422969872.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-09-19
- Estimated Expiration
- 2034-12-03
AI Technical Summary
Existing inertial measurement devices based on MEMS devices have not yet met the requirements of miniaturization, lightweight and high reliability in the fields of land navigation and mine inclinometers, especially in terms of size, weight, reliability and multi-functional integration.
A split-cavity design is adopted to separate the inertial unit cavity and the control cavity, and the main heat source is placed in the control cavity to reduce temperature interference; the IMU component is composed of a three-axis MEMS gyroscope and a three-axis MEMS accelerometer, which are set on the rotating axis and driven by a motor to rotate, periodically changing the working direction to average the zero bias error; miniaturized motors and bearings are used to ensure rotational stability and accuracy.
The inertial measurement device has been miniaturized and lightweight, the anti-interference capability and the accuracy of navigation solution have been improved, the zero bias error has been reduced, and the horizontal attitude angle and velocity accuracy have been improved.
Smart Images
Figure CN223361459U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of land navigation and mine inclination measurement, and particularly relates to an inertial measurement device based on a MEMS device. Background Art
[0002] MEMS (micro electromechanical system), also known as a micromechanical gyroscope, typically consists of micro sensors, signal processing and control circuits, communication interfaces, and power modules. Its goal is to integrate information acquisition, processing, and execution into a multifunctional microsystem, significantly improving the system's automation, intelligence, and reliability.
[0003] In-depth research into MEMS technology has led to significant development. MEMS inertial devices, with their advantages of small size, light weight, strong environmental adaptability, low price, and ease of mass automated production, have been widely adopted in the automotive and consumer electronics sectors. With further improvements in performance, MEMS gyroscopes have also expanded into other fields, including industry, aerospace, and inertial navigation.
[0004] Domestic MEMS gyroscopes have reached low-precision navigation levels, enabling their application in equipment such as missile inertial groups, low-precision north finders, and mining inclinometers, forming a MEMS-based inertial measurement unit (IMU). However, existing MEMS-based IMUs still need to be improved in terms of size, weight, reliability, and multifunctional integration. This is particularly true in areas such as land navigation and mine inclinometers, which require more compact, lightweight, and highly reliable solutions.
[0005] Therefore, providing an inertial measurement device based on MEMS devices is intended to solve the above problems and meet market demand, which is a technical problem that those skilled in the art hope to solve. Summary of the Invention
[0006] In response to the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide an inertial measurement device based on MEMS devices. The inertial measurement device described in the present invention has the advantages of miniaturization, lightweight and high reliability, and can meet the application requirements in technical fields such as land navigation and mine inclinometer measurement.
[0007] The technical solution of the present utility model is achieved as follows:
[0008] The inertial measurement device based on MEMS device comprises a shell, wherein the shell is cylindrical and an inertial group cavity, a motor cavity and a control cavity are sequentially arranged inside the shell from front to back along the axial direction of the shell.
[0009] A control component is provided in the control cavity; a motor is provided in the motor cavity, and the output shaft of the motor faces the inertia cavity.
[0010] A rotating shaft is provided in the inertial group cavity, which is arranged axially along the shell and has bearings at both ends of the rotating shaft. The rear end of the rotating shaft is connected to the output shaft of the motor; an IMU component is provided on the rotating shaft, and the IMU component includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer for collecting inertial data; a conductive slip ring is provided on the corresponding rotating shaft between the IMU component and the motor, which is used to connect the IMU component and the control component to transmit the inertial data to the control component for solution, and an encoder is provided at the front end of the rotating shaft, which is used to feedback the rotation angle and position information of the rotating shaft. The encoder and the motor are both connected to the control component, so that the control component can control the motor according to the inertial data and the feedback rotation angle and position information.
[0011] Furthermore, the shell is composed of a top cover, a first shell, a second shell, a third shell and a bottom cover. The first shell, the second shell and the third shell are cylindrical structures and correspond one-to-one to the inertia cavity, the motor cavity and the circuit cavity. The third shell and the second shell, the second shell and the first shell are fixedly connected by a number of fixing parts. The bottom cover is arranged on the end face of the third shell to close the end face of the third shell, and the top cover is arranged on the end face of the first shell to close the end face of the first shell.
[0012] Furthermore, the control component includes a navigation computer module, a power module, a communication module, and a motor drive module.
[0013] The navigation computer module is used to receive the inertial data collected by the IMU component and the rotation angle and position information fed back by the encoder, complete the error compensation processing of the IMU component, and complete the initial alignment and navigation solution of the IMU component.
[0014] The power module is connected to an external power source and is used to supply power to the motor, encoder and IMU components.
[0015] The communication module is used for communication between the IMU component and the control component, between the encoder and the control component, and between the control component and the motor, as well as for receiving control instructions.
[0016] The motor driver module is used to control the motor.
[0017] Furthermore, the device has an external dimension of ≤φ45×250mm and a weight of ≤800g.
[0018] Furthermore, the IMU component also includes a main control module for processing data and transmitting the data to the control component.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] This device utilizes a split-chamber design, separating the IMU chamber from the control chamber. The primary heat source is placed in the control chamber, effectively minimizing thermal interference with the IMU assembly and improving the device's anti-interference capabilities. Bearings at both ends of the rotating shaft ensure rotational stability and accuracy. The control unit adjusts the IMU's position based on encoder feedback to ensure accurate navigation solutions.
[0021] 2. This utility model utilizes miniaturized MEMS devices, such as a three-axis MEMS gyroscope and a three-axis MEMS accelerometer, to form an IMU assembly, effectively reducing the size and weight of the inertial measurement unit. The IMU assembly is mounted on a rotating shaft and driven by a motor to rotate about the celestial axis. This periodically changes the operating direction of the three-axis MEMS gyroscope and three-axis MEMS accelerometer, averaging their long-range biases in different directions. This offsets some bias errors, slowing the divergence of navigation horizontal attitude angle and velocity errors and improving horizontal attitude angle accuracy.
[0022] 3. The inertial measurement device of the present invention is miniaturized and lightweight. Specifically, the inertial measurement device of the present invention is cylindrical, and has an external dimension of ≤φ45×250mm and a weight of ≤800g. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 -Schematic diagram of the external structure of the utility model.
[0024] Figure 2 - Schematic diagram of the internal structure of the utility model.
[0025] Figure 3 -Schematic diagram of the internal structure of the inertial group cavity and the motor cavity.
[0026] Figure 4 - Schematic diagram of the internal structure of the control chamber.
[0027] Among them: 1-top cover; 2-first shell; 3-second shell; 4-third shell; 5-bottom cover; 6-control component; 6a-power module; 6b-navigation computer module; 6c-communication module; 6d-bracket; 6e-motor drive module; 7-motor; 8-rotating shaft; 9-conductive slip ring; 10-IMU component; 11-encoder; 12-bearing. DETAILED DESCRIPTION
[0028] The present invention will be described in further detail below with reference to the accompanying drawings and specific implementation methods.
[0029] See also Figure 1 、 Figure 2、 Figure 3 and Figure 4 The inertial measurement device based on MEMS devices includes a shell, which is cylindrical and has an inertial group cavity, a motor cavity and a control cavity arranged in sequence from front to back along the axial direction of the shell.
[0030] The control chamber is provided with a control assembly 6; the motor chamber is provided with a motor 7, and the output shaft of the motor 7 faces the inertia chamber;
[0031] A rotating shaft 8 is provided in the inertial group cavity. The rotating shaft 8 is arranged along the axial direction of the shell and bearings 12 are provided at both ends of the rotating shaft 8. The rear end of the rotating shaft 8 is connected to the output shaft of the motor 7; an IMU component 10 is provided on the rotating shaft 8, and the IMU component 10 includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer for collecting inertial data; a conductive slip ring 9 is provided on the rotating shaft 8 corresponding to the IMU component 10 and the motor 7, which is used to connect the IMU component 10 and the control component 6 to transmit the inertial data to the control component 6 for solution, and an encoder 11 is provided at the front end of the rotating shaft 8. The encoder 11 is used to feedback the rotation angle and position information of the rotating shaft 8. The encoder and the motor are both connected to the control component, so that the control component can control the motor according to the inertial data and the feedback rotation angle and position information.
[0032] Here, the use of miniaturized MEMS devices such as a three-axis MEMS gyroscope and a three-axis MEMS accelerometer can effectively reduce the size and weight of the device. In specific implementation, the inertial measurement device of the utility model has an external dimension of ≤φ45×250mm and a weight of ≤800g.
[0033] Furthermore, a split-chamber design separates the IMU chamber from the control chamber, with the primary heat source located in the control chamber. This effectively reduces thermal interference with the IMU components and improves the device's anti-interference capabilities. Bearings at both ends of the rotating shaft ensure rotational stability and accuracy. The control unit adjusts the IMU's position based on encoder feedback to ensure accurate navigation solutions.
[0034] At the same time, the IMU component is set on the rotating axis and rotated around the celestial axis by the motor. This can periodically change the working direction of the three-axis MEMS gyroscope and the three-axis MEMS accelerometer, so that the long-value zero bias of the three-axis MEMS gyroscope and the three-axis MEMS accelerometer (that is, the stable output deviation after long-term operation) will be averaged in different directions, thereby offsetting part of the zero bias error, thereby slowing down the divergence of the navigation horizontal attitude angle and velocity error, and improving the horizontal attitude angle accuracy.
[0035] In specific implementation, the shell is composed of a top cover 1, a first shell 2, a second shell 3, a third shell 4 and a bottom cover 5. The first shell 2, the second shell 3 and the third shell 4 are cylindrical structures and correspond one-to-one to the inertia cavity, the motor cavity and the circuit cavity. The third shell 4 and the second shell 3, the second shell 3 and the first shell 2 are fixedly connected by a number of screws. The bottom cover 5 is arranged on the end face of the third shell 4 to close the end face of the third shell 4, and the top cover 1 is arranged on the end face of the first shell 2 to close the end face of the first shell 2.
[0036] As shown in the figure, the front end of the third housing is inserted into the rear end of the second housing, and several screws are used to secure the second and third housings together. The front end of the second housing is inserted into the rear end of the first housing, and several screws are used to secure the first and second housings together. This allows for modular production of the first, second, and third housings, facilitating assembly of the corresponding components and housings, and improving the maintainability of the inertial measurement unit.
[0037] In specific implementation, the control component includes a navigation computer module 6b, a power module 6a, a communication module 6c, and a motor drive module 6e; as can be seen from the figure, the navigation computer module 6b, the power module 6a, the communication module 6c and the motor drive module 6e are arranged in the control cavity through a bracket 6d.
[0038] The navigation computer module 6b is used to receive the inertial data collected by the IMU component and the rotation angle and position information fed back by the encoder, complete the IMU component error compensation processing, and complete the IMU's gradual initial alignment and navigation solution.
[0039] The power module 6a is connected to an external power source and is used to supply power to the motor 7, encoder 11 and IMU component 10;
[0040] The communication module 6c is used for communication between the IMU component and the control component, between the encoder and the control component, and between the control component and the motor, as well as for receiving control instructions.
[0041] The motor driving module 6e is used to control the motor 7.
[0042] The IMU component uses a six-degree-of-freedom MEMS inertial measurement unit (IMU), consisting of a three-axis MEMS gyroscope, a three-axis MEMS accelerometer, and a main control module. The main control module, which includes control and signal processing circuits and serial port level conversion, serves as the data processing controller for the IMU. The operating temperature range is -40°C to 85°C, and the main performance indicators meet the design requirements.
[0043] The motor used in this utility model is a brushless DC motor with a Hall effect sensor. Its unique design ensures extremely smooth rotation, minimal cogging, and low total harmonic distortion. It boasts a compact size, light weight, low power consumption, and quiet operation. Its operating temperature range is -40°C to 85°C. The planetary reduction gearbox is highly precise, compact, and provides precise transmission and output torque to meet the design requirements.
[0044] The bearings are deep groove ball bearings suitable for supporting radial and bidirectional axial loads. Machining and assembly ensure high coaxiality between the shaft diameter and the housing bore at the bearing installation location. Appropriate fasteners (such as locknuts and washers) are used to secure the bearings to prevent displacement during operation, while allowing for adequate adjustment to account for thermal expansion.
[0045] The encoder is a hollow rotary absolute magnetic encoder. It consists of an axially magnetized ring and a readhead. Equipped with various communication interfaces, the encoder offers 24-bit resolution and 0.01° absolute accuracy. It operates from a 5VDC power supply, has an operating temperature range of -40°C to 85°C, and a maximum speed of 20,000 rpm.
[0046] The conductive slip ring adopts advanced precious metal cluster brush type multi-point contact to ensure reliable contact under extremely low friction, and transmits signal lines through the hole with a diameter of 12.7mm.
[0047] Finally, it should be noted that the above embodiments of the present invention are merely examples for illustrating the present invention and are not intended to limit the implementation methods of the present invention. Those skilled in the art will appreciate that other variations and modifications based on the above description are possible. It is not possible to enumerate all implementation methods here. Any obvious variations or modifications arising from the technical solution of the present invention remain within the scope of protection of the present invention.
Claims
1. An inertial measurement device based on a MEMS device, characterized in that: The housing comprises a cylindrical shell, wherein an inertia group chamber, a motor chamber and a control chamber are sequentially provided in the housing along the axial direction from front to back; The control chamber is provided with a control assembly; the motor chamber is provided with a motor, and the output shaft of the motor faces the inertia chamber; A rotating shaft is provided in the inertial group cavity, which is arranged axially along the shell and has bearings at both ends of the rotating shaft. The rear end of the rotating shaft is connected to the output shaft of the motor; an IMU component is provided on the rotating shaft, and the IMU component includes a three-axis MEMS gyroscope and a three-axis MEMS accelerometer for collecting inertial data; a conductive slip ring is provided on the corresponding rotating shaft between the IMU component and the motor, which is used to connect the IMU component and the control component to transmit the inertial data to the control component for solution, and an encoder is provided at the front end of the rotating shaft, which is used to feedback the rotation angle and position information of the rotating shaft. The encoder and the motor are both connected to the control component, so that the control component can control the motor according to the inertial data and the feedback rotation angle and position information.
2. The MEMS-based inertial measurement device according to claim 1, wherein: The shell is composed of a top cover, a first shell, a second shell, a third shell and a bottom cover. The first shell, the second shell and the third shell are cylindrical structures and correspond one-to-one to the inertia cavity, the motor cavity and the circuit cavity. The third shell and the second shell, the second shell and the first shell are fixedly connected by a number of fixing parts. The bottom cover is arranged on the end face of the third shell to close the end face of the third shell, and the top cover is arranged on the end face of the first shell to close the end face of the first shell.
3. The inertial measurement device based on MEMS devices according to claim 1, characterized in that: The control component includes a navigation computer module, a power module, a communication module, and a motor drive module; The navigation computer module is used to receive the inertial data collected by the IMU component and the rotation angle and position information fed back by the encoder, complete the IMU component error compensation processing, and complete the initial alignment and navigation solution of the IMU component; The power module is connected to an external power source and is used to power the motor, encoder and IMU components; The communication module is used for communication between the IMU component and the control component, between the encoder and the control component, and between the control component and the motor, as well as for receiving control instructions; The motor driver module is used to control the motor.
4. The MEMS-based inertial measurement device according to claim 1, wherein: The device has an external dimension of ≤φ45×250mm and a weight of ≤800g.
5. The inertial measurement device based on MEMS devices according to claim 1, characterized in that: The IMU component also includes a main control module for processing data and transmitting the data to the control component.