Inertial measurement device based on MEMS device

Abstract

The invention discloses an inertial measurement device based on an MEMS device, the inertial measurement device comprises a shell, the shell is cylindrical, an inertial measurement unit cavity, a motor cavity and a control cavity are sequentially arranged in the axial direction of the shell from front to back, and a control assembly is arranged in the control cavity; a motor is arranged in the motor cavity, and an output shaft of the motor faces the inertial measurement unit cavity; a rotating shaft is arranged in the inertial measurement unit cavity and is axially arranged along the shell, bearings are arranged at two ends of the rotating shaft, and the rear end of the rotating shaft is connected with a motor output shaft; the rotating shaft is provided with an IMU assembly, and the IMU assembly comprises a three-axis MEMS gyroscope and a three-axis MEMS accelerometer. A conductive slip ring is arranged on the corresponding rotating shaft between the IMU assembly and the motor, and an encoder is arranged at the front end of the rotating shaft and connected with the control assembly, so that the control assembly can conveniently send a control instruction to the motor according to inertial data and feedback rotation angle and position information. The inertial measurement device disclosed by the invention has the advantages of miniaturization, light weight, high reliability and the like, and can meet the application requirements in the technical fields of land navigation, mine inclinometry and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of land navigation and mine inclination measurement, and in particular relates to an inertial measurement device based on a MEMS device. Background Art

[0002] MEMS (micro electro mechanical system) is also called micro-electromechanical system, also known as micro-mechanical gyroscope, which is usually composed of micro sensors, signal processing and control circuits, communication interfaces and power modules. Its goal is to integrate the acquisition, processing and execution of information to form a multifunctional micro system, thereby greatly improving the automation, intelligence and reliability of the system.

[0003] With the in-depth research on MEMS technology, it has achieved great development. MEMS inertial devices have the advantages of small size, light weight, strong environmental adaptability, low price, and easy mass automated production. They have been widely used in the automotive and consumer electronics fields. With the further improvement of performance, MEMS gyroscopes have also been expanded to the fields of industry, aerospace, inertial navigation, etc.

[0004] Domestic MEMS gyroscopes have reached the level of low-precision navigation, so they can be applied to missile inertial groups, low-precision north finders, mining inclinometers and other equipment, thus forming inertial measurement devices based on MEMS devices. However, the existing inertial measurement devices based on MEMS devices still need to be improved in terms of volume, weight, reliability and multi-functional integration, especially in technical fields such as land navigation and mine inclinometers, which require more miniaturized, lightweight and highly reliable solutions.

[0005] Therefore, providing an inertial measurement device based on MEMS devices is intended to solve the above-mentioned problems. Meeting market demand is a technical problem that those skilled in the art hope to solve. Summary of the invention

[0006] In view of 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 of the present invention has the advantages of miniaturization, light weight and high reliability, and can meet the application requirements in technical fields such as land navigation and mine inclinometer.

[0007] The technical solution of the present invention is achieved in this way: An inertial measurement device based on a MEMS device comprises a shell, wherein the shell is cylindrical and an inertial measurement chamber, a motor chamber and a control chamber are sequentially arranged in the shell from front to back along the axial direction of the shell.

[0008] A control component is arranged in the control cavity; a motor is arranged in the motor cavity, and an output shaft of the motor faces toward the inertia assembly cavity.

[0009] A rotating shaft is provided in the inertial group cavity, the rotating shaft is arranged along the axial direction of the shell and bearings are provided at both ends of the rotating shaft, and 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 rotating shaft corresponding to 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, and the encoder 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.

[0010] 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 by one to the inertia group 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.

[0011] Furthermore, the control component includes a navigation computer module, a power module, a communication module, and a motor drive module.

[0012] 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.

[0013] The power module is connected to an external power source and is used to supply power to the motor, encoder and IMU components.

[0014] 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.

[0015] The motor driver module is used to control the motor.

[0016] Furthermore, the device has an overall dimension of ≤φ45×250mm and a weight of ≤800g.

[0017] Furthermore, the IMU component also includes a main control module for processing data and transmitting the data to the control component.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a split-chamber design, separating the IMU chamber and the control chamber, and placing the main heat source in the control chamber, effectively reducing the interference of temperature on the IMU component and improving the anti-interference ability of the device. Bearings are set at both ends of the rotating shaft to effectively ensure the stability and rotation accuracy of the rotating shaft. The control component will correct the position of the IMU according to the feedback of the encoder to ensure the accuracy of the navigation solution.

[0019] 2. The present invention uses miniaturized MEMS devices such as a three-axis MEMS gyroscope and a three-axis MEMS accelerometer to form an IMU component, which can effectively reduce the volume and weight of the inertial measurement device. At the same time, the IMU component is set on the rotating shaft and rotated around the celestial axis by a motor, so that the working direction of the three-axis MEMS gyroscope and the three-axis MEMS accelerometer can be periodically changed, so that the long-value zero bias of the three-axis MEMS gyroscope and the three-axis MEMS accelerometer can 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.

[0020] 3. The inertial measurement device of the present invention is miniaturized and lightweight. Specifically, the inertial measurement device of the present invention is columnar, and has an outer dimension of ≤φ45×250mm and a weight of ≤800g. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 - Schematic diagram of the external structure of the present invention.

[0022] Figure 2 - Schematic diagram of the internal structure of the present invention.

[0023] Figure 3 -Schematic diagram of the internal structure of the inertial cavity and the motor cavity.

[0024] Figure 4 - Schematic diagram of the internal structure of the control chamber.

[0025] 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

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] See also Figure 1 , Figure 2 , Figure 3 and Figure 4An inertial measurement device based on a MEMS device 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 in the shell along the axial direction of the shell.

[0028] A control assembly 6 is disposed in the control cavity; a motor 7 is disposed in the motor cavity, and the output shaft of the motor 7 faces the inertia cavity; 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, and 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, and 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.

[0029] Here, miniaturized MEMS devices such as a three-axis MEMS gyroscope and a three-axis MEMS accelerometer are used to effectively reduce the size and weight of the device. In a specific implementation, the inertial measurement device of the present invention has an external dimension of ≤φ45×250mm and a weight of ≤800g.

[0030] At the same time, a split-chamber design is adopted here, with the inertial chamber and the control chamber separated, and the main heat source is placed in the control chamber, which effectively reduces the interference of temperature on the IMU components and improves the anti-interference ability of the device. Bearings are set at both ends of the rotating shaft to effectively ensure the stability and rotation accuracy of the rotating shaft. The control component will correct the position of the IMU according to the feedback of the encoder to ensure the accuracy of the navigation solution.

[0031] At the same time, the IMU component is set on the rotating axis and driven by the motor to rotate around the celestial axis. 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 (that is, the stable output deviation after long-term operation) of the three-axis MEMS gyroscope and the three-axis MEMS accelerometer 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.

[0032] 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 by one to the inertia group 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.

[0033] As can be seen from the figure, the front end face of the third housing is inserted into the rear end face of the second housing, and the second housing and the third housing are fixedly connected by a number of screws, and the front end face of the second housing is inserted into the rear end face of the first housing, and the first housing and the second housing are fixedly connected by a number of screws. In this way, the first housing, the second housing and the third housing can be produced and processed in a modular manner, which is convenient for the assembly of the corresponding components and the housing, and can also improve the maintainability of the inertial measurement device.

[0034] 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.

[0035] 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 error compensation processing of the IMU component, and complete the initial alignment and navigation solution of the IMU.

[0036] The power module 6a is connected to an external power source and is used to supply power to the motor 7, the encoder 11 and the IMU component 10; 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.

[0037] The motor driving module 6 e is used to control the motor 7 .

[0038] In the specific implementation, the IMU component uses a six-degree-of-freedom MEMS inertial measurement unit, which consists of a three-axis MEMS gyroscope, a three-axis MEMS accelerometer, and a main control module. The main control module has circuits such as control and signal processing and serial port level conversion, and is the data processing controller of the inertial measurement device. The operating temperature range is -40℃~85℃, and the main performance indicators can meet the requirements of this design.

[0039] The motor used in the present invention is a reduction motor, a brushless DC motor, and a Hall sensor. The motor adopts a special design mechanism to make it rotate very smoothly, with very small cogging effect and very low total harmonic distortion. It has the advantages of small size, light weight, low power, quiet operation, etc. The operating temperature range is -40℃~85℃. The planetary reduction box has high precision, small size, precise transmission, and provides output torque, which can meet the design.

[0040] The bearing is a deep groove ball bearing, suitable for bearing radial load and bidirectional axial load. Through machining and assembly, the shaft diameter and the bearing seat hole at the bearing installation position are ensured to have a high degree of coaxiality. Appropriate fasteners (such as lock nuts, washers, etc.) are used to fix the bearing to prevent displacement during operation. At the same time, considering the influence of thermal expansion, appropriate adjustment space is left.

[0041] The encoder is a hollow rotary absolute magnetic encoder. The encoder consists of an axial magnetized ring and a reading head. The encoder is equipped with a variety of communication interfaces and provides 24-bit resolution, an absolute accuracy of 0.01°, a 5VDC power supply, an operating temperature of -40 to 85°C, and a maximum speed of 20,000 rpm.

[0042] 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.

[0043] Finally, it should be noted that the above embodiments of the present invention are only examples for illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still 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 housing, wherein an inertia chamber, a motor chamber and a control chamber are sequentially arranged in the housing from front to back along the axial direction of the housing; 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, the rotating shaft is arranged along the axial direction of the shell and bearings are provided at both ends of the rotating shaft, and 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 rotating shaft corresponding to 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, and the encoder 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 inertial measurement device based on a MEMS device according to claim 1, characterized in that: 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 to the inertia group cavity, the motor cavity and the circuit cavity one by one. 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 device 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 error compensation processing of the IMU component, and complete the initial alignment and navigation solution of the IMU component; The power module is connected to an external power supply and is used to supply power to 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, and for receiving control instructions; The motor driver module is used to control the motor.

4. The inertial measurement device based on a MEMS device according to claim 1, characterized in that: The device has an overall size of ≤φ45×250mm and a weight of ≤800g.

5. The inertial measurement device based on MEMS device 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.

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