Three-axis magnetic field sensor calibration device based on three-R-axis rotating system

Abstract

The utility model discloses a three-axis magnetic field sensor calibration device. A pure wood frame supporting structure is a long-strip-shaped structure; the three-R-axis rotating part has self electromagnetic shielding performance, the three-axis magnetic field sensor is installed on the three-R-axis rotating part and is far away from parts with electromagnetic interference in the three-R-axis rotating part, and the three-R-axis rotating part can drive the three-axis magnetic field sensor to rotate in three R-axis directions so that the rotating posture of the three-axis magnetic field sensor can cover the whole three-dimensional space; the three-R-axis rotation control part is used for controlling the three-R-axis rotation part to rotate in the three R-axis directions. According to the device, measurement information of the three-axis magnetic field sensor fully covers a three-dimensional space range where an ellipsoid is located through three-R-axis rotation, so that magnetic field interference of the rotating device and ground environment interference magnetic fields such as ferromagnetic soil and rocks on the three-axis magnetic field sensor in the use process is greatly reduced and even eliminated; and the calibration precision and accuracy of the three-axis magnetic field sensor are improved.

Description

Technical Field

[0001] This utility model relates to the field of magnetic field measurement technology, specifically to a calibration device for a three-axis magnetic field sensor based on a three-R-axis rotation system. Background Technology

[0002] During the manufacturing process of triaxial magnetic field sensors, errors such as non-orthogonality, sensitivity, and zero-offset are unavoidable. Non-orthogonality refers to the inability to guarantee perfect pairwise orthogonality between the three measurement axes during manufacturing. Sensitivity error arises from differences in the sensitivity of each axis and inconsistencies in the amplification circuit characteristics of the measurement signals. Zero-offset error refers to the fact that internal electronic components, analog circuit design, and analog-to-digital signal conversion cause the output value to be non-zero when the magnetic field strength is zero, resulting in a zero-point offset error. These errors render the data obtained from high-precision triaxial magnetic field sensors unusable directly, requiring calibration of the measured values.

[0003] Common error calibration methods for triaxial magnetic field sensors are divided into two categories: auxiliary vector calibration methods and independent scalar calibration methods. Auxiliary vector calibration methods compare the data of the triaxial magnetic field sensor with a known magnetic flux density vector field to assist in calibration. However, in practical applications, it is difficult to obtain a high-precision known triaxial magnetic flux density vector. Independent scalar calibration methods avoid this drawback by rotating the triaxial magnetic field sensor within a constant magnetic field, using a fixed total magnetic flux density as a constraint for calibration. Independent scalar calibration methods have attracted considerable research and widespread application due to their ease of operation in practical environments. A typical example is the magnetic compensation method based on the ellipsoid assumption. This method selects a relatively clean magnetic field environment, rotates the triaxial magnetic field sensor across the entire spatial range, and uses the total Earth's magnetic flux density as a constant constraint for a short period, performing real-time measurements to obtain a rich set of measurement values. These values ​​are then used to calibrate the triaxial magnetic field sensor's non-orthogonality error, sensitivity error, and zero-bias error. Existing independent scalar calibration methods for triaxial magnetic field sensors have problems such as the rotating platform not being three R-axis, significant magnetic field interference from the rotating platform, insufficient coverage of the entire three-dimensional space by the rotation trajectory of the triaxial magnetic field sensor, and insufficient distribution information on the ellipsoid.

[0004] To address the challenges of independent scalar calibration methods for triaxial magnetic field sensors, which require rotating the sensor within a spatial range, maintaining a constant total Earth magnetic field intensity over a short period, minimizing magnetic field interference during rotation, ensuring a constant surrounding magnetic field, and maximizing the uniform and widespread distribution of measured magnetic field intensity information across the ellipsoid, a triaxial magnetic field sensor calibration device based on a three-R-axis rotation system is proposed. Utility Model Content

[0005] To address the shortcomings of existing technologies, the technical problem to be solved is to provide a triaxial magnetic field sensor calibration device based on a three-R-axis rotation system. This device allows the magnetic induction intensity measured by the triaxial magnetic field sensor to fully cover the three-dimensional space of the entire ellipsoid, and greatly reduces or even eliminates the magnetic field interference of the rotating device itself and the ground environment such as ferromagnetic soil and rocks on the triaxial magnetic field sensor during use, thereby increasing the accuracy and precision of the triaxial magnetic field sensor calibration.

[0006] To achieve the above objectives, the following technical solution is used: a triaxial magnetic field sensor calibration device based on a three-R-axis rotation system, comprising:

[0007] The structure is supported by a pure wood frame and is a long, narrow structure.

[0008] A three-R-axis rotating component, possessing its own electromagnetic shielding, is mounted on the pure wooden frame support structure. A triaxial magnetic field sensor is installed on the three-R-axis rotating component, away from any electromagnetically interfering components within it. The three-R-axis rotating component enables the triaxial magnetic field sensor to rotate in three R-axis directions, allowing the magnetic induction intensity measured by the sensor to cover the entire three-dimensional space of the ellipsoid.

[0009] The three-R-axis rotation control component is communicatively connected to the three-R-axis rotating component and is used to control the rotation of the three-R-axis rotating component in the three R-axis directions.

[0010] Furthermore, the pure wood frame support structure includes square mounting planks and a support frame with a square cross-section. The support frame includes multiple support rods, which are joined together by mortise and tenon joints to form the support frame with a square cross-section. The mounting planks cover and are fixed to the top of the support frame.

[0011] Furthermore, the three R-axis rotating component includes a first rotating drive component, a second rotating drive component, a third rotating drive component, a first connecting portion, a second connecting portion, and a cylindrical wooden frame mounting bracket. The first rotating drive component, the second rotating drive component, and the third rotating drive component are sequentially connected through the first connecting portion and the second connecting portion. The first connecting portion and the first rotating drive component are rotatable relative to each other, and the second connecting portion and the second rotating drive component are rotatable relative to each other. The first rotating drive component is connected to the top of the pure wood frame support structure. The cylindrical wooden frame mounting bracket is elongated. One end of the cylindrical wooden frame mounting bracket is rotatably connected to the third rotating drive component. The triaxial magnetic field sensor is installed at the other end of the cylindrical wooden frame mounting bracket away from the third rotating drive component.

[0012] Furthermore, both the first connecting part and the second connecting part are box-shaped aluminum alloy plates. The box-shaped aluminum alloy plate includes two vertical side plates and two horizontal plates. A circular hole is opened on one of the horizontal plates and one of the vertical side plates, and the center of the circular hole is located at the geometric center of the bottom horizontal plate and the vertical side plate, respectively.

[0013] Furthermore, the first rotary drive, the second rotary drive, and the third rotary drive include a hollow rotary platform, a precision servo motor, and an electromagnetic shielding encapsulation shell;

[0014] The hollow rotating platform includes an annular rotating component, a bottom fixing component, and a motor connection port. The annular rotating component is rotatably mounted on the bottom fixing component.

[0015] The bottom fixing component of the hollow rotating platform of the first rotating drive component is fixedly connected to the top of the pure wood frame support structure, and the annular rotating component of the hollow rotating platform of the first rotating drive component is sleeved and fixed to the round hole on the horizontal plate at the bottom of the first connecting part.

[0016] The bottom fixing component of the hollow rotating platform of the second rotating drive component is sleeved and fixed with the round hole on the vertical side plate of the first connecting part, and the annular rotating component of the hollow rotating platform of the second rotating drive component is sleeved and fixed with the round hole on the vertical side plate of the second connecting part.

[0017] The bottom fixing component of the hollow rotating platform of the third rotating drive component is fixedly connected to the horizontal plate of the second connecting part, and the annular rotating component of the hollow rotating platform of the third rotating drive component is fixedly connected to one end of the cylindrical wooden frame mounting bracket.

[0018] The precision servo motor is mounted on the motor connection port and connected to the corresponding annular rotating component, and is used to drive the annular rotating component to rotate.

[0019] The electromagnetic shielding enclosure is located outside the corresponding hollow rotating platform and the precision servo motor, and is open-type.

[0020] Furthermore, the rotary drive can decelerate and increase the rotational torque, and the deceleration ratio of the rotary drive is 1:10.

[0021] Furthermore, the electromagnetic shielding enclosure includes a rotating shielding enclosure and a fixed shielding enclosure. The rotating shielding enclosure is placed over the annular rotating component, and the fixed shielding enclosure is used to cover the bottom fixing component, the motor connection port, and the precision servo motor together. The rotating shielding enclosure and the fixed shielding enclosure are not closed to each other and can move relative to each other.

[0022] Furthermore, both the rotating shielding encapsulation shell and the fixed shielding encapsulation shell include, from the inside out, a high-damping, high-strength rubber layer one, a double-sided silver-plated copper sheet layer, a high-damping, high-strength rubber layer two, a silicon steel sheet layer, a high-damping, high-strength rubber layer three, and a permalloy layer, which are sequentially stacked. Adjacent layers are bonded together with flexible acrylic adhesive.

[0023] Furthermore, the cylindrical wooden frame mounting bracket is a hollow component, and the cylindrical wooden frame mounting bracket includes multiple vertical wooden rods and multiple arc-shaped wooden tenons. The multiple vertical wooden rods are evenly spaced circumferentially, and adjacent vertical wooden rods are connected by the arc-shaped wooden tenons. The bottom fixing component of the hollow rotating platform of the third rotating drive component is connected to one end of the vertical wooden rod.

[0024] Furthermore, the three-R-axis rotation control component includes three servo motor drivers, a power supply, a three-axis servo motor controller, and a waterproof housing. The three servo motor drivers are connected to the three precision servo motors respectively via three multi-core cables, each corresponding to one of them. The three-axis servo motor controller communicates with the three servo motor drivers via multi-core cables. The waterproof housing covers the three servo motor drivers, the power supply, and the three-axis servo motor controller.

[0025] Beneficial effects of this medicine:

[0026] The aforementioned triaxial magnetic field sensor calibration device based on a three-R-axis rotation system transmits signals to the three-R-axis rotating component through the three-R-axis rotation control component, causing the triaxial magnetic field sensor to rotate in the three R-axis directions. Its rotational posture covers the entire three-dimensional space, allowing the magnetic induction intensity measured by the triaxial magnetic field sensor to fully cover the three-dimensional space of the entire ellipsoid. It also greatly reduces or even eliminates the magnetic field interference of the rotating device itself and the ground environment such as ferromagnetic soil and rocks on the triaxial magnetic field sensor during use, thereby increasing the accuracy and precision of the triaxial magnetic field sensor calibration. Attached Figure Description

[0027] To more clearly illustrate this specific embodiment, the accompanying drawings used in the specific embodiment will be briefly described below. In all the drawings, the elements or components are not necessarily drawn to actual scale.

[0028] Figure 1 This is a schematic diagram of a three-axis magnetic field sensor calibration device based on a three-R-axis rotation system provided in this embodiment;

[0029] Figure 2 This is a schematic diagram of the pure wood frame support structure in the triaxial magnetic field sensor calibration device based on a three-R-axis rotation system of this utility model;

[0030] Figure 3 This is a schematic diagram showing the structure of the rotary drive component in the triaxial magnetic field sensor calibration device based on a three-R-axis rotation system, and its rotation direction relative to the pure wood frame support structure and the cylindrical wooden frame mounting bracket.

[0031] Figure 4 This is a schematic diagram of the hollow rotating platform in the three-axis magnetic field sensor calibration device based on a three-R-axis rotating system of this utility model;

[0032] Figure 5 This is a schematic diagram of the cylindrical wooden frame mounting bracket in the triaxial magnetic field sensor calibration device based on a three-R-axis rotation system of this utility model;

[0033] Figure 6 This is a schematic diagram of the first connecting part and the second connecting part in the triaxial magnetic field sensor calibration device based on the three R-axis rotation system of this utility model;

[0034] Figure 7 This is a cross-sectional schematic diagram in the vertical plane of the hollow rotating platform of the three-R-axis rotating component and the electromagnetic shielding package of the precision servo motor in the three-axis magnetic field sensor calibration device based on the three-R-axis rotating system of this utility model.

[0035] Figure 8 This is a schematic diagram of the communication control of the three-axis magnetic field sensor calibration device based on a three-R-axis rotation system according to this utility model;

[0036] Figure label:

[0037] 1. Solid wood frame support structure; 2. Three R-axis rotating component; 3. Three R-axis rotating control component; 4. Multi-core cable; 5. Supporting wooden pole; 6. Mounting wooden board; 7. First rotating drive component; 8. Second rotating drive component; 9. Third rotating drive component; 10. Precision servo motor; 11. First connecting part; 12. Second connecting part; 13. Cylindrical wooden frame mounting bracket; 14. Annular rotating component; 15. Bottom fixing component; 16. Motor connection port; 17. Arc-shaped wooden tenon; 18. Horizontal plate; 19. Vertical side plate; 20. Rotary shielding enclosure; 21. Fixed shielding enclosure; 22. Servo motor driver; 23. Power supply; 24. Three-axis servo motor controller; 25. Waterproof housing; 26. Vertical wooden pole. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0039] Please see Figures 1 to 8 This invention provides a three-axis magnetic field sensor calibration device based on a three-R-axis rotation system, including a pure wood frame support structure 1, a three-R-axis rotating component 2, and a three-R-axis rotation control component 3.

[0040] Specifically, the pure wood frame support structure 1 is a long strip structure. The three R-axis rotating component 2 has its own electromagnetic shielding and is mounted on the pure wood frame support structure 1. The three-axis magnetic field sensor is mounted on the three R-axis rotating component 2 and is located away from any electromagnetically interfering components within the three R-axis rotating component. The three R-axis rotating component 2 can drive the three-axis magnetic field sensor to rotate in the three R-axis directions, so that the magnetic induction intensity measured by the three-axis magnetic field sensor covers the entire three-dimensional space of the ellipsoid. The three R-axis rotation control component 3 is communicatively connected to the three R-axis rotating component 2 and is used to control the rotation of the three R-axis rotating component 2 in the three R-axis directions.

[0041] In use, the three-R-axis rotation control component 3 transmits signals to the three-R-axis rotating component 2, causing the three-axis magnetic field sensor to rotate in the three R-axis directions. Its rotation posture covers the entire three-dimensional space, allowing the magnetic induction intensity measured by the three-axis magnetic field sensor to fully cover the three-dimensional space of the entire ellipsoid. It also greatly reduces or even eliminates the magnetic field interference of the rotating device itself and the ground environment such as ferromagnetic soil and rocks on the three-axis magnetic field sensor during use, thereby increasing the accuracy and precision of the three-axis magnetic field sensor calibration.

[0042] Please see Figure 2 Specifically, in this embodiment, the pure wood frame support structure 1 includes a square mounting board 6 and a support frame with a square cross-section. The support frame includes multiple support rods 5, which are joined together by mortise and tenon joints to form a support frame with a square cross-section. The mounting board 6 is fixed to the top of the support frame.

[0043] In practical implementation, four supporting wooden poles 5 can be selected, and twelve short wooden poles can be used for dowels. The four supporting wooden poles and twelve wooden poles are spliced ​​together to form a pure wooden frame support structure 1. For example, when the dimensions of the pure wooden frame support structure 1 are 300mm long, 300mm wide, and 3000mm high, the four supporting wooden poles 5 are 3000mm long, the twelve wooden poles 5 (including the tenon and mortise joints) are 300mm long, and the side length of the mounting board 6 is 300mm. Circular holes are made in the mounting board 6 for installing other components. The connections between the wooden poles are all made using tenon and mortise joints. Neither the wooden poles nor the board contains any metal materials, and the connections do not use any metal materials such as nails or bolts. The wooden poles and the board are connected using cylindrical wooden dowels. Through the pure wooden frame support structure 1, the three-R-axis rotating component 2 is 3000mm above the ground, and the three-axis magnetic field sensor carried by the three-R-axis rotating component 2 is far away from the ground, avoiding the influence of ground environment interference magnetic fields such as ferromagnetic soil and rocks on the three-axis magnetic field sensor.

[0044] In this embodiment, the three R-axis rotating component 2 includes a first rotating drive component 7, a second rotating drive component 8, a third rotating drive component 9, a first connecting part 11, a second connecting part 12, and a cylindrical wooden frame mounting bracket 13. The first rotating drive component 7, the second rotating drive component 8, and the third rotating drive component 9 are sequentially connected via the first connecting part 11 and the second connecting part 12. The first connecting part 11 and the first rotating drive component 7 are rotatable relative to each other, and the second connecting part 12 and the second rotating drive component 8 are rotatable relative to each other. The first rotating drive component 7 is connected to the top of the pure wood frame support structure 1. The cylindrical wooden frame mounting bracket 13 is elongated and has two ends, including an M end and an N end (see...). Figure 5 The M end of the cylindrical wooden frame mounting bracket 13 is rotatably connected to the third rotary drive component 9, and the triaxial magnetic field sensor is mounted on the N end of the cylindrical wooden frame mounting bracket 13 away from the third rotary drive component 9.

[0045] Please see Figure 6 Specifically, both the first connecting part 11 and the second connecting part 12 are box-shaped aluminum alloy plates. Each box-shaped aluminum alloy plate includes two vertical side plates 19 and two horizontal plates 18. The box-shaped aluminum alloy plate includes eight nodes: A, B, C, D, E, F, G, and H. The plates containing points A, B, F, and E, and the plates containing points C, D, H, and G, are the two vertical side plates 19. The plates containing points A, B, C, and D, and the plates containing points E, F, G, and H, are the two horizontal plates 18. A circular hole is opened on one of the bottom horizontal plates 18 and one of the vertical side plates 19; that is, the plates with circular holes are the horizontal plate containing points E, F, G, and H, and the vertical side plate containing points C, D, H, and G. The centers of the two circular holes are located at the geometric centers of the horizontal plate 18 and the vertical side plate 19, respectively.

[0046] The circular holes are used to connect with the corresponding rotary drive components. The centers of the circular holes are located at the geometric centers of the bottom horizontal plate 18 and the vertical side plate 19, respectively, which ensures that the object is in force balance during rotation and improves rotational stability.

[0047] Please see Figure 3 In this embodiment, the first rotary drive 7, the second rotary drive 8, and the third rotary drive 9 include a hollow rotary platform, a precision servo motor 10, and an electromagnetic shielding encapsulation shell.

[0048] Please see Figure 4 The hollow rotating platform includes an annular rotating component 14, a bottom fixing component 15, and a motor connection port 16. The annular rotating component 14 is rotatably mounted on the bottom fixing component 15.

[0049] The first bottom fixing component 15 is fixedly connected to the top of the pure wood frame support structure 1, and the first annular rotating component 14 is fixedly connected to the round hole on the bottom horizontal plate 18 of the first connecting part 11.

[0050] The second bottom fixing component 15 is sleeved and fixed to the round hole on the vertical side plate 19 of the first connecting part 11, and the second annular rotating component 14 is sleeved and fixed to the round hole on the vertical side plate 19 of the second connecting part 12.

[0051] The third bottom fixing component 15 is fixedly connected to the horizontal plate 18 of the second connecting part 12, and the third annular rotating component 14 is fixedly connected to the M end of the cylindrical wooden frame mounting bracket 13.

[0052] A precision servo motor 10 is mounted on a motor connection port 16 and connected to the corresponding annular rotating component 14, for driving the annular rotating component 14 to rotate.

[0053] The electromagnetic shielding enclosure is located outside the corresponding hollow rotating platform and precision servo motor 10, and is open-type.

[0054] In use, the precision servo motor 10 drives the corresponding annular rotating part 14 to rotate, which in turn drives the corresponding connecting part to rotate, and finally drives the cylindrical wooden frame mounting bracket 13. The specific speed of rotation is controlled by the three R-axis rotation control component 3. The speed, direction and number of rotations can be the same or different, ultimately realizing the rotation of the three-axis magnetic field sensor.

[0055] Please see Figure 7 In this embodiment, the electromagnetic shielding enclosure includes a rotating shielding enclosure 20 and a fixed shielding enclosure 21. The rotating shielding enclosure 20 covers the annular rotating member 14. In the cross-sectional view of the plumb line, it presents two anti-symmetrical n-shapes.

[0056] The fixed shielding enclosure 21 is used to cover the bottom fixed component 15, the motor connection port 16 and the precision servo motor 10 together, and the rotating shielding enclosure 20 and the fixed shielding enclosure 21 are not closed to each other and can move relative to each other, that is, there is an opening.

[0057] Both the rotating shielding enclosure 20 and the fixed shielding enclosure 21 include, from the inside out, a high-damping, high-strength rubber layer 1, a double-sided silver-plated copper sheet layer, a high-damping, high-strength rubber layer 2, a silicon steel sheet layer, a high-damping, high-strength rubber layer 3, and a permalloy layer, which are sequentially stacked. Adjacent layers are bonded together with flexible acrylic adhesive.

[0058] In this manner, the rotating shielding enclosure 20 of the annular rotating component 14 covers both the external and internal openings of the annular rotating component 14 of the hollow rotating platform. The electromagnetic shielding enclosure of the inner annular portion extends to the bottommost part of the bottom fixing component 15 of the hollow rotating platform. The entire rotating shielding enclosure 20 of the annular rotating component 14 of the hollow rotating platform rotates together with the annular rotating component 14. The rotating shielding enclosure 20 of the annular rotating component 14 of the hollow rotating platform has two anti-symmetrical n-shapes in the cross-sectional view of the plumb line.

[0059] The bottom fixing component 15, motor connection port 16, and precision servo motor 10 of the hollow rotating platform are covered and encapsulated together by the fixed shielding shell 21. The fixed shielding shell 21 of the motor connection port 16 has an opening, but the opening overlaps to facilitate the passage of the multi-core cable 4. At the same time, the overlap at the opening prevents a weakening of the electromagnetic shielding effect at the opening.

[0060] Furthermore, the fixed shielding enclosure 21 covering the bottom fixing component 15, motor connection port 16, and precision servo motor 10 of the hollow rotating platform extends externally to the top of the annular rotating component 14 of the hollow rotating platform, overlapping with the rotating shielding enclosure 20 of the annular rotating component 14 of the hollow rotating platform with a gap; the fixed shielding enclosure 21 covering the bottom fixing component 15, motor connection port 16, and precision servo motor 10 of the hollow rotating platform extends internally to the top of the annular rotating component 14 of the hollow rotating platform, overlapping with the rotating shielding enclosure 20 of the annular rotating component 14 of the hollow rotating platform with a gap. In this way, when the annular rotating component 14 of the hollow rotating platform rotates, the two electromagnetic shielding enclosures, namely the fixed shielding enclosure 21 and the rotating shielding enclosure 20, will not collide, and the overlap avoids the weakening of the electromagnetic shielding effect at the opening.

[0061] In practical implementation, the materials for the rotating shielding enclosure 20 and the fixed rotating shielding enclosure 20 can be selected as follows:

[0062] The first layer is a 2mm thick high-damping, high-strength rubber layer; the second layer is a double-sided silver-plated copper sheet with a total thickness of 0.3mm (including the silver plating and copper); the third layer is a 2mm thick high-damping, high-strength rubber layer made of silicon steel; the fourth layer is a 0.6mm thick silicon steel sheet; the fifth layer is a 2mm thick high-damping, high-strength rubber layer made of silicon steel; and the sixth layer is a 0.6mm thick permalloy layer made of permalloy. The six layers are bonded together using flexible acrylic adhesive. The parameters of the high-damping, high-strength rubber are: elastic modulus > 5MPa, damping ratio > 0.2, tensile strength > 10MPa, and ultimate elongation > 300%. The parameters for double-sided silver-plated copper sheets are as follows: the copper content is >99%, the copper conductivity is >58 MS / m, the single-sided silver plating layer thickness is >20 micrometers, and the silver used in the silver plating layer has a silver content >99.9%. The parameters for silicon steel sheets are: initial permeability >5000 H / m, maximum permeability >20000 H / m. The parameters for permalloy are: initial permeability >30000 H / m, maximum permeability >500000 H / m. The elongation after curing of the acrylic flexible adhesive is >200%. When using an electromagnetic shielding encapsulation shell for shielding, it covers and wraps the object to be shielded. The inner surface of the electromagnetic shielding encapsulation shell is the first layer material, and the outer surface is the sixth layer material.

[0063] Please see Figure 5 In this embodiment, the cylindrical wooden frame mounting bracket 13 can be a hollow part with a length of 2000mm.

[0064] The cylindrical wooden frame mounting bracket 13 includes multiple vertical wooden rods 26 and multiple arc-shaped wooden tenons 17. The multiple vertical wooden rods 26 are evenly spaced around the circumference, and adjacent vertical wooden rods 26 are connected by arc-shaped wooden tenons 17. The bottom fixing component 15 of the third rotary drive component 9 is connected to the M end of the vertical wooden rods 26.

[0065] The elongated cylindrical wooden frame mounting bracket 13 keeps the triaxial magnetic field sensor away from the hollow rotating platform and the precision servo motor 10, greatly reducing the magnetic field interference from these components. The electromagnetic shielding enclosure shields the static magnetic field of the hollow rotating platform and the precision servo motor 10, as well as the high-frequency magnetic field generated during operation, further minimizing the magnetic field interference. The hollow cylindrical wooden frame mounting bracket 13, keeping the triaxial magnetic field sensor away from the hollow rotating platform and the precision servo motor 10, along with the electromagnetic shielding enclosure, significantly reduces magnetic field interference, enabling the triaxial magnetic field sensor to measure a constant Earth's magnetic field strength.

[0066] In practical implementation: there can be 10 vertical wooden rods 26, each 2000mm long, with a square cross-section and a side length of 50mm. At 500mm and 1500mm intervals, the vertical wooden rods 26 are connected by arc-shaped wooden tenons 17, thus forming one wooden ring on the entire circumference at each of the 500mm and 1500mm intervals, resulting in two wooden rings. At the N-end of the cylindrical wooden frame mounting bracket 13, which is located away from the hollow rotating platform and is connected to the annular rotating component 14, each wooden rod has a through hole with a truncated square. A triaxial magnetic field sensor requiring calibration is installed at the through hole of the truncated square and fixed using a thin wooden wedge.

[0067] Please see Figure 8 In this embodiment, the three-R-axis rotation control component 3 comprises four parts: three servo motor drivers 22, a power supply 23, a three-axis servo motor controller 24, and a waterproof housing 25. The three servo motor drivers 22 are connected to three precision servo motors 10 via three multi-core cables 4, each corresponding to one of them. The three-axis servo motor controller 24 communicates with the three servo motor drivers 22 via the multi-core cables 4. The precision servo motors 10 mounted on the first, second, and third hollow rotating platforms can each be independently controlled by the three-axis servo motor controller 24, and the three precision servo motors 10 can rotate at different speeds, directions, and angles. The program is input into the three-axis servo motor controller 24, and the three-axis servo motor controller 24 issues instructions to the three servo motor drivers 22. The three servo motor drivers 22 then control the rotation of the corresponding three precision servo motors 10 of the three R-axis rotating parts. The three precision servo motors 10 drive the annular rotating parts 14 of the three hollow rotating platforms of the three R-axis rotating parts to rotate, thereby enabling the hollow cylindrical wooden frame mounting bracket 13 of the three R-axis rotating parts to achieve the rotational movement of the three R axes.

[0068] The above-mentioned triaxial magnetic field sensor calibration device based on a three-R-axis rotation system is used as follows:

[0069] When using a triaxial magnetic field sensor calibration device based on a three-R-axis rotation system, the device should be placed in an open outdoor environment, away from buildings, towers, and other ferromagnetic materials. This ensures that the Earth's magnetic field strength at that location remains constant during the short calibration period, with the rotation and calibration process for a single triaxial magnetic field sensor not exceeding 10 minutes. A precise, high-precision triaxial magnetometer should be positioned no more than 1000mm away from the calibration device. During calibration, the high-precision triaxial magnetometer measures the Earth's magnetic field strength at that location. The triaxial magnetic field sensor is placed at the N-end of the square wooden rod of a hollow cylindrical wooden frame mounting bracket 13. Signals are transmitted to the three-R-axis rotating component 2 via the three-R-axis rotation control component 3, causing the triaxial magnetic field sensor to rotate in all three R-axis directions. This rotation covers the entire three-dimensional space, ensuring that the magnetic field strength measured by the triaxial magnetic field sensor fully covers the three-dimensional space of the entire ellipsoid. The Earth's magnetic field strength is measured by fully rotating a triaxial magnetic field sensor and by a high-precision triaxial magnetometer. The non-orthogonality error, sensitivity error, and zero bias error of the triaxial magnetic field sensor are calibrated by an independent scalar calibration method.

[0070] The above technical solution has the following advantages:

[0071] The triaxial magnetic field sensor calibration device based on the three-R-axis rotation system enables the measurement information of the triaxial magnetic field sensor to fully cover the three-dimensional space range where the ellipsoid is located through three-R-axis rotation. It also greatly reduces or even eliminates the magnetic field interference of the rotating device itself and the ground environment such as ferromagnetic soil and rocks on the triaxial magnetic field sensor during use, thereby increasing the accuracy and precision of the triaxial magnetic field sensor calibration.

[0072] The above embodiments are only used to illustrate the technical solutions of this invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to the components or all technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present embodiments, and they should all be covered within the scope of the claims and specification of this invention.

Claims

1. A three-axis magnetic field sensor calibration device based on a three-R- axis rotation system, characterized by The application relates to a pure wood frame support structure, a three-R-axis rotating part, and a three-R-axis rotating control part. The pure wood frame support structure is a long strip structure; the three-R-axis rotating part has self electromagnetic shielding property and is arranged on the pure wood frame support structure; a three-axis magnetic field sensor is arranged on the three-R-axis rotating part and is far away from a zero component with electromagnetic interference in the three-R-axis rotating part; the three-R-axis rotating part can drive the three-axis magnetic field sensor to rotate in three R-axis directions, so that the magnetic induction intensity measured by the three-axis magnetic field sensor covers the three-dimensional space of an entire ellipsoid. The three-R-axis rotating control part is in communication connection with the three-R-axis rotating part and is used for controlling the three-R-axis rotating part to rotate in three R-axis directions. The pure wood frame support structure comprises a square mounting wood plate and a support wood frame with a square cross section; the support wood frame comprises a plurality of support wood poles which are connected into the support wood frame with a square cross section through tenon and mortise connection; and the mounting wood plate is fixedly covered on the top of the support wood frame. The three-R-axis rotating part comprises a first rotating driving part, a second rotating driving part, a third rotating driving part, a first connecting part, a second connecting part and a cylindrical wood frame mounting frame; the first rotating driving part, the second rotating driving part and the third rotating driving part are sequentially connected through the first connecting part and the second connecting part; the first connecting part can rotate relative to the first rotating driving part; the second connecting part can rotate relative to the second rotating driving part; the first rotating driving part is connected with the top of the pure wood frame support structure; the cylindrical wood frame mounting frame is in a long strip shape; one end of the cylindrical wood frame mounting frame is rotatably connected with the third rotating driving part; and the three-axis magnetic field sensor is arranged on the other end of the cylindrical wood frame mounting frame which is far away from the third rotating driving part.

2. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 1, characterized in that, The first connecting part and the second connecting part are both box-shaped aluminum alloy plates; the box-shaped aluminum alloy plate comprises two vertical side plates and two horizontal plates; a circular hole is formed in one of the horizontal plates and one of the vertical side plates; and the centers of the circular holes are respectively located at the geometric centers of the bottom horizontal plate and the vertical side plate.

3. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 1, characterized in that, The first rotating driving part, the second rotating driving part and the third rotating driving part comprise a hollow rotating platform, a precision servo motor and an electromagnetic shielding packaging shell.

4. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 3, characterized in that The hollow rotating platform comprises a ring-shaped rotating part, a bottom fixing part and a motor connecting port; the ring-shaped rotating part is rotatably arranged on the bottom fixing part.

5. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 4, characterized in that The bottom fixing part of the hollow rotating platform of the first rotating driving part is fixedly connected with the top of the pure wood frame support structure; and the ring-shaped rotating part of the hollow rotating platform of the first rotating driving part is fixedly sleeved with the circular hole in the bottom horizontal plate of the first connecting part. The bottom fixing part of the hollow rotating platform of the second rotating driving part is fixedly sleeved with the circular hole in the vertical side plate of the first connecting part; and the ring-shaped rotating part of the hollow rotating platform of the second rotating driving part is fixedly sleeved with the circular hole in the vertical side plate of the second connecting part. ​ ​ The bottom fixed part of the hollow rotating platform of the third rotating driving member is fixedly connected with the horizontal plate of the second connecting part, and the annular rotating part of the hollow rotating platform of the third rotating driving member is fixedly connected with one end of the cylindrical wooden frame mounting rack; The precision servo motor is mounted on the motor connecting port and connected with the corresponding annular rotating part, for driving the annular rotating part to rotate. The electromagnetic shielding packaging shell is arranged outside the corresponding hollow rotating platform and the precision servo motor, and is open.

6. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 3 or 5, characterized in that The rotating driving member can reduce speed and increase rotational torque, and the speed reduction ratio of the rotating driving member is 1:

10.

7. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 5, characterized in that, The electromagnetic shielding packaging shell includes a rotating shielding packaging shell and a fixed shielding packaging shell, the rotating shielding packaging shell is arranged outside the annular rotating part, the fixed shielding packaging shell is used for covering the bottom fixed part, the motor connecting port and the precision servo motor together, and the rotating shielding packaging shell and the fixed shielding packaging shell can be not closed and can move relative to each other.

8. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 7, characterized in that The rotating shielding packaging shell and the fixed shielding packaging shell each include, from inside to outside, a high-damping high-strength rubber layer one, a double-sided silver-plated copper sheet layer, a high-damping high-strength rubber layer two, a silicon steel sheet layer, a high-damping high-strength rubber layer three and a permalloy layer, and adjacent layers are bonded by acrylic flexible glue.

9. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 3, characterized in that, The cylindrical wooden frame mounting rack is a hollow member, and includes a plurality of vertical wooden poles and a plurality of arc-shaped wooden dowels, the plurality of vertical wooden poles are arranged in a circumferential direction at equal intervals, adjacent vertical wooden poles are connected by the arc-shaped wooden dowels, and the bottom fixed part of the hollow rotating platform of the third rotating driving member is connected with one end of the vertical wooden pole.

10. The three-axis magnetic field sensor calibration apparatus based on a three-R- axis rotation system according to claim 1, characterized in that, The three-R-axis rotating control part includes three servo motor drivers, a power supply, a three-axis servo motor controller and a waterproof housing, the three servo motor drivers are respectively connected with three precision servo motors through three multi-core cables, each one-to-one corresponding, the three-axis servo motor controller is communicatively connected with the three servo motor drivers through a multi-core cable, and the waterproof housing covers the three servo motor drivers, the power supply and the three-axis servo motor controller.

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