Digital weak magnetic field measuring instrument based on three-axis magnetic sensor

Abstract

The invention discloses a digital weak magnetic field measuring instrument based on a three-axis magnetic sensor, and relates to the technical field of magnetic field measuring instruments and teaching aids, the digital weak magnetic field measuring instrument comprises a three-axis magnetic sensor module, a signal processing circuit module, a control module and a magnetic field wave oscilloscope module, the three-axis magnetic sensor module is used for generating magnetic induction intensity signals; the signal processing circuit module comprises a differential signal circuit, an amplifying circuit and an analog-to-digital conversion circuit; the differential signal circuit, the amplifying circuit and the analog-to-digital conversion circuit are used for forming a differential signal, an analog signal and a digital signal respectively; the control module comprises a bottom surface parameter position resolving module, a z-axis parameter position resolving module and a vector cube module which are respectively used for resolving a coordinate parameter position of a bottom surface rectangle, resolving a coordinate parameter position of a z-axis and synthesizing a magnetic field vector; and the magnetic field wave oscilloscope module is used for acquiring and displaying a magnetic field waveform. The system has the advantages of being high in anti-interference capability and good in teaching effect.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic field measuring instruments and teaching aids, and in particular to a digital weak magnetic field measuring instrument based on a three-axis magnetic sensor. Background Art

[0002] With the continuous progress of science and technology, weak magnetic field measurement technology is increasingly used in many fields such as military, aviation, ocean, geology, archaeology, biology, medicine and teaching experiments. These fields have put forward higher and higher requirements on the accuracy, stability and portability of weak magnetic field measuring instruments. As a highly sensitive device for detecting and studying weak magnetic field changes, the performance of weak magnetic field measuring instruments directly affects the research progress and practical application effects of related disciplines.

[0003] At present, the mainstream weak magnetic field measurement methods include Hall effect method, magneto-optical effect method, superconducting quantum interference device, atomic magnetometer and magnetostriction method. Among them, the Hall effect method has been widely used in the field of weak magnetic field measurement due to its advantages such as low cost, high precision and easy processing. However, the traditional Hall effect weak magnetic field measuring instrument is easily affected by various interference factors during the measurement process, such as micromagnetic interference between components, common mode interference of circuits, the influence of temperature on the performance of electronic components, the electromagnetic induction effect of metal materials, and the high-frequency electromagnetic clutter and low-frequency geomagnetic field disturbance commonly present in the air. These interference factors will cause fluctuations and inaccuracies in the measurement results, limiting the performance and application scope of the measuring instrument. At the same time, the weak magnetic field measuring instrument in the current teaching experiment has a single display content and poor display effect, which reduces the teaching quality. Therefore, it is of great research significance and application value to study and develop a new type of digital weak magnetic field measuring instrument based on a three-axis magnetic sensor. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a digital weak magnetic field measuring instrument based on a three-axis magnetic sensor.

[0005] A digital weak magnetic field measuring instrument based on a three-axis magnetic sensor comprises a three-axis magnetic sensor module, a signal processing circuit module, a control module and a magnetic field wave oscilloscope module; wherein the three-axis magnetic sensor module is used to sense a weak magnetic field and generate a magnetic induction intensity signal, wherein the magnetic induction intensity signal is represented by a voltage signal; the signal processing circuit module comprises a differential signal circuit, an amplifying circuit and an analog-to-digital conversion circuit, wherein the differential signal circuit is used to receive a voltage signal and form a differential signal according to a reference voltage signal, the amplifying circuit is used to receive a differential signal and amplify the differential signal to an analog signal within a preset voltage range, and the analog-to-digital conversion circuit is used to receive an analog The control module comprises a bottom surface parameter position solving module, a z-axis parameter position solving module and a vector cube module, wherein the bottom surface parameter position solving module is used to establish a 45-degree oblique coordinate system of a plane and solve the coordinate parameter position of a bottom rectangle located in the 45-degree oblique coordinate system of the plane according to the digital signal, the z-axis parameter position solving module is used to solve the coordinate parameter position of the z-axis according to the digital signal and the parameter position of each point of the bottom surface rectangle, and the vector cube module is used to synthesize a magnetic field vector according to the coordinate parameter position of the bottom surface rectangle and the coordinate parameter position of the z-axis; and the magnetic field wave oscilloscope module is used to obtain and display the magnetic field waveform according to the magnetic field vector.

[0006] Preferably, the bottom surface parameter position solving module includes a coordinate system establishing unit and a vector bottom surface solving unit, the coordinate system establishing unit is used to establish a 45-degree oblique coordinate system in the plane, and the vector bottom surface solving unit is used to obtain the x-axis component and the y-axis component according to the digital signal and solve the coordinate parameter position of the bottom surface rectangle located in the 45-degree oblique coordinate system in the plane according to the x-axis component and the y-axis component.

[0007] Preferably, the z-axis parameter bit solution module includes a z-axis component acquisition unit and a copy offset unit, wherein the copy offset unit is used to acquire the z-axis component according to the digital signal, and the copy offset unit is also used to copy and offset the coordinate parameter bits of the bottom rectangle according to the z-axis component and form the coordinate parameter bits of the z-axis.

[0008] Preferably, it also includes a self-test magnetic field generation module, which includes two coil bodies and a constant current input unit. The constant current input unit is used to connect the coil bodies according to a preset current value, and the two coil bodies are used to generate a weak magnetic field after being connected and be sensed by the three-axis magnetic sensor module.

[0009] Preferably, the control module also includes a calculation module and an adjustment module, wherein the calculation module is used to obtain the theoretical magnetic field size according to a magnetic field calculation model including a first correction parameter, and the adjustment module is used to adjust the first correction parameter according to the magnetic field vector and the theoretical magnetic field size and obtain the second correction parameter.

[0010] Preferably, the magnetic field calculation model is expressed as: Where B is the theoretical magnetic field size, N is the number of turns of the coil body, I is the preset current value, μ 0 is the vacuum magnetic permeability, R is the coil radius, x is the center distance between the two coil bodies, α 1 is the first correction parameter.

[0011] Preferably, it also includes a human-computer interaction interface, and the human-computer interaction interface is used to display the magnetic field vector.

[0012] Preferably, it further comprises a filtering module electrically connected to the three-axis magnetic sensor module and the differential signal circuit, wherein the filtering module is used to filter the voltage signal.

[0013] Preferably, it also includes a power supply module electrically connected to the three-axis magnetic sensor module, the signal processing circuit module and the control module.

[0014] Preferably, the magnetic induction intensity includes x-axis intensity, y-axis intensity and z-axis intensity.

[0015] The beneficial effects of the present invention are embodied in:

[0016] In the entire digital weak magnetic field measuring instrument based on the three-axis magnetic sensor, the common mode interference is effectively removed through the differential signal circuit, and the mutual interference between circuits is reduced. The design of the amplification circuit and the analog-to-digital conversion circuit further enhances the anti-interference of the signal and ensures the stability of the measurement results; further, the high-precision three-axis magnetic sensor is adopted, which can simultaneously measure the magnetic induction intensity in three directions. The amplification circuit and the analog-to-digital conversion circuit in the signal processing circuit module ensure the accuracy and stability of the signal, thereby realizing high-precision measurement of weak magnetic fields; further, the vector cube module in the control module displays the magnetic field vector in an intuitive form, which is convenient for analyzing the measurement results; further, the magnetic field wave oscilloscope module records the magnetic field vector data and processes and displays the magnetic field waveform. Therefore, by integrating the three-axis magnetic sensor module, the signal processing circuit module and the control module, the problems of the traditional Hall effect weak magnetic field measuring instrument being susceptible to interference, low precision and poor display effect during the measurement process are effectively solved, and high-precision and stable measurement of weak magnetic fields is realized, and it has good anti-interference ability, portability and display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0018] Figure 1A schematic diagram of steps in one embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the composition of the signal processing circuit module of the present invention;

[0020] Figure 3 It is a schematic diagram of the composition of the control module of the present invention;

[0021] Figure 4 It is a schematic diagram of the composition of the self-test magnetic field generation module of the present invention;

[0022] Figure 5 It is a schematic diagram of steps in another embodiment of the present invention.

[0023] Reference numerals:

[0024] 100-three-axis magnetic sensor module, 200-signal processing circuit module, 210-differential signal circuit, 220-amplification circuit, 230-analog-to-digital conversion circuit, 300-control module, 310-bottom surface parameter bit solution module, 311-coordinate system establishment unit, 312-vector bottom surface solution unit, 320-z-axis parameter bit solution module, 321-z-axis component acquisition unit, 322-copy offset unit, 330-vector cube module, 340-calculation module, 350-adjustment module, 400-self-test magnetic field generation module, 410-coil body, 420-constant current input unit, 500-human-computer interaction interface, 600-filter module, 700-magnetic field wave oscilloscope module. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0028] like Figures 1 to 3 As shown, a digital weak magnetic field measuring instrument based on a three-axis magnetic sensor is provided, comprising a three-axis magnetic sensor module 100, a signal processing circuit module 200 and a control module 300; wherein,

[0029] The three-axis magnetic sensor module 100 is used to sense weak magnetic field signals and generate magnetic induction intensity signals, wherein the magnetic induction intensity signals are represented by voltage signals;

[0030] The signal processing circuit module 200 includes a differential signal circuit 210, an amplifier circuit 220, and an analog-to-digital conversion circuit 230. The differential signal circuit 210 is used to receive a voltage signal and form a differential signal. The amplifier circuit 220 is used to receive the differential signal and amplify the differential signal to an analog signal within a preset voltage range. The analog-to-digital conversion circuit 230 is used to receive the analog signal and convert the analog signal into a digital signal.

[0031] The control module 300 includes a bottom surface parameter position solving module 310, a z-axis parameter position solving module 320 and a vector cube module 330. The bottom surface parameter position solving module 310 is used to establish a 45-degree oblique coordinate system of a plane and solve the coordinate parameter position of a bottom surface rectangle located in the 45-degree oblique coordinate system of the plane according to a digital signal. The z-axis parameter position solving module 320 is used to solve the coordinate parameter position of the z-axis according to the digital signal and the parameter position of each point of the bottom surface rectangle. The vector cube module 330 is used to synthesize a magnetic field vector according to the coordinate parameter position of the bottom surface rectangle and the coordinate parameter position of the z-axis.

[0032] The magnetic field wave oscilloscope module is used to obtain and display the magnetic field waveform according to the magnetic field vector.

[0033] In this embodiment, it should be noted that the three-axis magnetic sensor module 100 can use the QMC5883 Hall element to sense weak magnetic fields and generate magnetic induction intensity signals. The magnetic induction intensity is represented by a voltage signal, so that the change in the magnetic field can be converted into an electrical signal for processing; wherein, the three-axis magnetic sensor can simultaneously measure the magnetic induction intensity in the x, y, and z directions, providing a data basis for subsequent vector synthesis.

[0034] The signal processing circuit module 200 includes a differential signal circuit 210, an amplifier circuit 220 and an analog-to-digital conversion circuit 230. The differential signal circuit 210 is used to receive the voltage signal from the three-axis magnetic sensor module 100, and use the instrument electrical grounding to connect the main circuit to form a reference voltage. This reference voltage is subtracted from the voltage signal formed by connecting the three-axis magnetic sensor to form a differential signal. In this case, the common-mode interference effect on the connection circuit between the main circuit and the three-axis magnetic sensor caused by the difference between the instrument electrical grounding and the earth's standard electromotive force can be well removed. The influence on the measurement result caused by the common-mode interference effect on the connection circuit between the main circuit and the three-axis magnetic sensor caused by the difference between the instrument electrical grounding and the earth's standard electromotive force. Further, the amplifier circuit 220 amplifies the differential signal to an analog signal within a preset voltage range. The amplified signal is easier to process and measure, and the signal's anti-interference ability is further enhanced. Further, the analog-to-digital conversion circuit 230 converts the analog signal into a digital signal, which is convenient for subsequent data processing and storage, and also improves the measurement accuracy and stability. In the preferred experiment, the amplified analog signal is immediately converted into a digital signal through a 16-bit analog-to-digital conversion circuit 230, which has stable transmission, is easy to process, and is basically not interfered with. Finally, 8×10 -9 T micromagnetic change, that is, to achieve 10 -8 T-level weak magnetic field measurement.

[0035] The control module 300 includes a bottom surface parameter position solving module 310, a z-axis parameter position solving module 320 and a vector cube module 330. The bottom surface parameter position solving module 310 can establish a 45-degree oblique coordinate system of a plane, and solve the coordinate parameter position of the bottom surface rectangle located in the coordinate system according to the digital signal; this step is the basis of vector synthesis. The z-axis parameter position solving module 320 further solves the coordinate parameter position of the z-axis according to the parameter position of each point of the bottom surface rectangle. In this way, the complete coordinates of the magnetic field vector in three-dimensional space are obtained. The vector cube module 330 synthesizes the magnetic field vector according to the coordinate parameter position of the bottom surface rectangle and the coordinate parameter position of the z-axis.

[0036] This process can be implemented using the main function code as follows:

[0037] / / Oblique coordinate system

[0038] ui_X=roundf(33.94*x_out / range);

[0039] ui_Y=roundf(48.0*y_out / range);

[0040] ui_Z=roundf(48.0*z_out / range);

[0041] LCD_Fill(0, 0, 128, 112, WHITE);

[0042] LCD_ShowChinese(16, 0, "Micro Magnetic Vector", BLACK, WHITE, 16, 0);

[0043] LCD_ShowIntNum(80, 0, range, 3, BLACK, WHITE, 16);

[0044] LCD_ShowString(104, 0, "uT", BLACK, WHITE, 16, 1);

[0045] / / Vector Cube

[0046] / / Bottom Surface

[0047] LCD_DrawLine(64, 64, 64 - ui_X + ui_Y, 64 + ui_X, GRAY);

[0048] LCD_DrawLine(64, 64, 64 - ui_X, 64 + ui_X, GRAY);

[0049] LCD_DrawLine(64 - ui_X, 64 + ui_X, 64 - ui_X + ui_Y, 64 + ui_X, GRAY);

[0050] LCD_DrawLine(64, 64, 64 + ui_Y, 64, GRAY);

[0051] LCD_DrawLine(64 + ui_Y, 64, 64 - ui_X + ui_Y, 64 + ui_X, GRAY);

[0052] / / Column

[0053] LCD_DrawLine(64 - ui_X + ui_Y, 64 + ui_X, 64 - ui_X + ui_Y, 64 + ui_X - ui_Z, BRED);

[0054] LCD_DrawLine(64, 64, 64, 64 - ui_Z, BRED);

[0055] LCD_DrawLine(64 + ui_Y, 64, 64 + ui_Y, 64 - ui_Z, BRED);

[0056] LCD_DrawLine(64 - ui_X, 64 + ui_X, 64 - ui_X, 64 + ui_X - ui_Z, BRED);

[0057] / / Top Surface

[0058] LCD_DrawLine(64, 64-ui_Z, 64-ui_X+ui_Y, 64+ui_X-ui_Z, GRAY);

[0059] LCD_DrawLine(64, 64-ui_Z, 64-ui_X, 64+ui_X-ui_Z, GRAY);

[0060] LCD_DrawLine(64-ui_X, 64+ui_X-ui_Z, 64-ui_X+ui_Y, 64+ui_X-ui_Z, GRAY);

[0061] LCD_DrawLine(64, 64-ui_Z, 64+ui_Y, 64-ui_Z, GRAY);

[0062] LCD_DrawLine(64+ui_Y, 64-ui_Z, 64-ui_X+ui_Y, 64+ui_X-ui_Z, GRAY);

[0063] LCD_DrawLine(64, 64, 64-ui_X+ui_Y, 64+ui_X-ui_Z, RED);

[0064] Draw_Circle(64-ui_X+ui_Y, 64+ui_X-ui_Z, 1, RED);

[0065] This code is used to draw a three-dimensional figure (vector cube) representing a weak magnetic field vector. The code first converts the magnetic field strength (x_out, y_out, z_out) in the x, y, and z directions output by the three-axis magnetic sensor into coordinates (ui_X, ui_Y, ui_Z) displayed on the LCD screen through a series of calculations and conversions. Then, it uses these coordinates to draw a vector cube to visually represent the strength and direction of the magnetic field.

[0066] ui_X, ui_Y, ui_Z are calculated by dividing the raw magnetic field strength values ​​(x_out, y_out, z_out) by a range value (range) and multiplying by the corresponding scaling factors (33.94 for the x-axis and 48.0 for the y-axis and z-axis). These scaling factors may be determined based on the resolution of the LCD screen and the range of magnetic field strength. The roundf function is used to round the calculation results to the nearest integer for use when drawing on the LCD screen.

[0067] LCD screen initialization: LCD_Fill(0, 0, 128, 112, WHITE); is used to fill the entire LCD screen with white.

[0068] Display text and numerical values: LCD_ShowChinese is used to display the Chinese character "micro magnetic vector". LCD_ShowIntNum and LCD_ShowString are used to display the range and unit (uT) of the magnetic field strength.

[0069] Draw a three-dimensional coordinate system: Use the Draw_Circle and LCD_DrawLine functions to draw a simple graph representing a three-dimensional coordinate system, including a center point, three coordinate axes (X, Y, Z), and arrows on the axes.

[0070] Draw a vector cube: Bottom surface: Use the LCD_DrawLine function to draw the bottom surface of the cube according to the values of ui_X and ui_Y. The bottom surface is a rectangle, and its size and position are determined by ui_X and ui_Y. Uprights: Draw four uprights connecting the bottom surface and the top surface. The length of the uprights is determined by ui_Z, and the color is BRED (possibly dark red). Top surface: Draw the top surface of the cube according to the values of ui_X, ui_Y, and ui_Z. The top surface is also a rectangle, parallel to the bottom surface but its position is determined by ui_Z.

[0071] Finally, draw a red line from the origin (64, 64) to the vertex of the cube and draw a small dot at the vertex to highlight the vector direction of the magnetic field.

[0072] Through the above process, the magnetic field wave oscilloscope module 700 receives magnetic field vector data and finally visually displays it in the form of waveforms on the LCD screen. This display method not only helps users intuitively understand the changes in the magnetic field but also provides an important visualization tool for subsequent magnetic field analysis.

[0073] In summary, in the entire digital weak magnetic field measuring instrument based on the three-axis magnetic sensor, the differential signal circuit 210 is used to effectively remove common-mode interference and reduce mutual interference between circuits. The design of the amplifying circuit 220 and the analog-to-digital conversion circuit 230 further enhances the anti-interference ability of the signal and ensures the stability of the measurement results. Furthermore, a high-precision three-axis magnetic sensor is used to simultaneously measure the magnetic induction intensity in three directions. The amplifying circuit 220 and the analog-to-digital conversion circuit 230 in the signal processing circuit module 200 ensure the accuracy and stability of the signal, thereby achieving high-precision measurement of weak magnetic fields. Furthermore, the vector cube module 330 in the control module 300 displays the magnetic field vector in an intuitive form, which is convenient for analyzing the measurement results. Furthermore, the magnetic field wave oscilloscope module 700 records the magnetic field vector data and processes and displays the magnetic field waveform. Therefore, by integrating the three-axis magnetic sensor module 100, the signal processing circuit module 200 and the control module 300, the problems of the traditional Hall effect weak magnetic field measuring instrument being susceptible to interference, low precision and poor display effect during the measurement process are effectively solved, and high-precision and stable measurement of weak magnetic fields is achieved, and it has good anti-interference ability, portability and display effect.

[0074] like Figure 3 As shown, in one embodiment, the bottom surface parameter position solving module 310 includes a coordinate system establishing unit 311 and a vector bottom surface solving unit 312, the coordinate system establishing unit 311 is used to establish a 45-degree oblique coordinate system in the plane, and the vector bottom surface solving unit 312 is used to obtain the x-axis component and the y-axis component according to the digital signal and solve the coordinate parameter position of the bottom surface rectangle located in the 45-degree oblique coordinate system in the plane according to the x-axis component and the y-axis component.

[0075] In the present embodiment, it should be noted that the main task of the coordinate system establishment unit 311 is to establish a plane 45 degree oblique coordinate system. This coordinate system is the basis for subsequent vector solution and visualization. By defining a specific plane coordinate system with an angle of inclination of 45 degrees, the projection of the magnetic field vector on the two-dimensional plane can be more conveniently represented and calculated while retaining certain three-dimensional space information. The establishment of the coordinate system makes the representation of the magnetic field vector more intuitive and easy to understand, and provides convenience for drawing a magnetic field vector diagram on an LCD screen or other display device in the future.

[0076] The vector bottom surface solving unit 312 receives digital signals from the signal processing circuit module 200, which represent the components of the magnetic field in the x-axis, y-axis and z-axis directions. Then, based on the values ​​of these components, the vector bottom surface solving unit 312 solves the coordinate parameter positions of the bottom surface rectangle located in the above-mentioned plane 45-degree oblique coordinate system.

[0077] It should also be noted that the x-axis and y-axis magnetic field component values ​​are extracted from the digital signal; then, the x-axis and y-axis component values ​​are used to solve the coordinate parameter positions of the four vertices of the bottom rectangle in the established 45-degree oblique coordinate system. This process involves basic geometric calculations and coordinate system conversion. By solving the coordinate parameter positions of the bottom rectangle, the bottom projection of the magnetic field vector can be drawn on the display device, thereby intuitively showing the direction and strength of the magnetic field. This is of great significance for understanding and analyzing the changes in weak magnetic fields.

[0078] like Figure 3 As shown, in one embodiment, the z-axis parameter bit solution module 320 includes a z-axis component acquisition unit 321 and a copy offset unit 322. The copy offset unit 322 is used to obtain the z-axis component according to the digital signal. The copy offset unit 322 is also used to copy and offset the coordinate parameter bits of the bottom rectangle according to the z-axis component and form the coordinate parameter bits of the z-axis.

[0079] In this embodiment, it should be noted that the main task of the z-axis component acquisition unit is to obtain the z-axis component from the digital signal. The digital signal is obtained by the signal processing circuit module 200 after differential, amplification and analog-to-digital conversion of the weak magnetic field signal sensed by the three-axis magnetic sensor. The z-axis component represents the strength of the magnetic field in the z-axis direction.

[0080] The copy offset unit 322 has two main tasks. First, it needs to obtain the z-axis component from the digital signal, which partially overlaps with the function of the z-axis component acquisition unit 321, but here it is emphasized that this unit will use this z-axis component for subsequent calculations. Second, it "copy offsets" the coordinate parameter bits of the bottom rectangle according to the obtained z-axis component, thereby forming the coordinate parameter bits of the z-axis.

[0081] Copy offset process: First, copy the coordinate parameter bits of the bottom rectangle on the xy plane, which describe the positions of the four vertices of the bottom rectangle. Then, according to the value of the z-axis component, these vertices are offset in the z-axis direction, and the amount of offset is proportional to the value of the z-axis component. In this way, the bottom rectangle originally on the xy plane is "stretched" or "compressed" into a part of a cube or cuboid in three-dimensional space. Finally, through this process, we get the complete coordinate parameter bits of the cube or cuboid in three-dimensional space, including the position of the bottom rectangle on the xy plane and the offset in the z-axis direction caused by the z-axis component.

[0082] like Figure 4As shown, in one embodiment, it also includes a self-test magnetic field generation module 400, which includes two coil bodies 410 and a constant current input unit 420. The constant current input unit 420 is used to connect the coil bodies 410 according to a preset current value. The two coil bodies 410 are used to generate a weak magnetic field after being connected and are sensed by the three-axis magnetic sensor module 100.

[0083] In this embodiment, it should be noted that when current passes through the coil, a magnetic field is generated around the coil according to the principle of electromagnetic induction, and two coil bodies 410 are used, which are arranged in a specific manner (such as orthogonal or parallel) to generate a magnetic field of a specific direction and strength. The weak magnetic field generated by the two coil bodies 410 after the current is turned on will be sensed by the three-axis magnetic sensor module 100 for the self-test process. By controlling the magnitude and direction of the current in the coil, the strength and direction of the generated magnetic field can be accurately controlled.

[0084] The constant current input unit 420 is responsible for providing a stable and controllable current to the coil body 410; it connects the coil according to the preset current value to ensure that the magnetic field generated during each self-test is repeatable and known. By accurately controlling the current, the stability and consistency of the magnetic field during the self-test process can be ensured, thereby improving the accuracy and reliability of the self-test.

[0085] When a self-test is required, the constant current input unit 420 connects the two coil bodies 410 according to the preset current value. After the current is turned on, the coil body 410 generates a weak magnetic field, which will be sensed by the three-axis magnetic sensor module 100. The three-axis magnetic sensor module 100 converts the sensed magnetic field signal into an electrical signal, which is processed and analyzed by the subsequent signal processing circuit module 200. By comparing the processed signal with the expected value (the magnetic field strength calculated based on the known current and coil characteristics), the accuracy and performance of the measuring instrument can be evaluated.

[0086] like Figure 3 As shown, in one embodiment, the control module 300 also includes a calculation module 340 and an adjustment module 350, the calculation module 340 is used to obtain the theoretical magnetic field size according to a magnetic field calculation model including a first correction parameter, and the adjustment module 350 is used to adjust the first correction parameter according to the magnetic field vector and the theoretical magnetic field size and obtain the second correction parameter.

[0087] In this embodiment, it should be noted that the main task of the calculation module 340 is to calculate the theoretical magnetic field size according to a magnetic field calculation model including a first correction parameter; this magnetic field calculation model can be established based on physical laws (such as Biot-Savart law or Maxwell equations) to describe the magnetic field distribution generated by a magnetic field source (such as current, magnet, etc.); the first correction parameter is a parameter used to adjust the model prediction result, which may reflect the deviation caused by the measurement environment, sensor characteristics or the approximation of the model itself. By calculating the theoretical magnetic field size, the calculation module 340 provides a reference value for subsequent measurement and calibration; this reference value is used to compare with the actual measured magnetic field to evaluate the accuracy of the measurement.

[0088] The adjustment module 350 is responsible for adjusting the first correction parameter according to the difference between the magnetic field vector (i.e., the actual measured magnetic field size and direction) and the theoretical magnetic field size, thereby obtaining the second correction parameter. This adjustment process may involve iterative calculations, optimization algorithms, or machine learning techniques to find the correction parameter that minimizes the error between the theoretical prediction and the actual measurement. By adjusting the correction parameter, the adjustment module 350 can gradually reduce the deviation between the model prediction and the actual measurement, thereby improving the accuracy of the measurement; the second correction parameter is an optimized parameter, which more accurately reflects the actual situation of the measurement environment and the characteristics of the sensor, and can therefore be used in subsequent measurements to further improve the accuracy of the measurement.

[0089] The specific steps may be: using the three-axis magnetic sensor module 100 to measure the magnetic field vector; the calculation module 340 calculates the theoretical magnetic field size according to the magnetic field calculation model including the first correction parameter; the adjustment module 350 compares the actually measured magnetic field vector and the theoretical magnetic field size, adjusts the first correction parameter according to the difference, and obtains the second correction parameter; uses the second correction parameter to update the magnetic field calculation model, performs the next measurement, and repeats the above process until the required measurement accuracy is achieved.

[0090] In one embodiment, the magnetic field calculation model is expressed as:

[0091] in,

[0092] B is the theoretical magnetic field size, N is the number of turns of the coil body, I is the preset current value, μ 0 is the vacuum magnetic permeability, R is the coil radius, x is the center distance between the two coil bodies, α 1 is the first correction parameter.

[0093] In this embodiment, it should be noted that the first half of the formula It is the magnitude of the magnetic field calculated based on the principle of electromagnetism and is used to describe the magnetic field distribution generated by the coil body. 1 / α 1It is a correction to the basic magnetic field calculation. Since there may be various deviations and interferences in actual measurement, the correction parameter α is introduced. 1 To adjust the theoretical calculation value to make it closer to the actual measurement result, the specific correction calculation standard is obtained and improved by comparing the actual value with the expected value during multiple tests or multiple self-tests.

[0094] like Figure 5 As shown, in one embodiment, a human-machine interaction interface 500 is also included, and the human-machine interaction interface 500 is used to display the magnetic field vector.

[0095] In this embodiment, it should be noted that one of the core functions of the human-computer interaction interface 500 is to display the magnetic field vector in real time. This includes the size of the magnetic field (i.e., magnetic induction intensity) and the direction. By displaying this information in a graphical or numerical manner, the user can intuitively understand the magnetic field state of the current measurement point. The magnetic field vector usually includes components in the three directions of x, y, and z, which can be represented by arrows, coordinate axes, or other graphical elements, so that the user can clearly see the distribution and changes of the magnetic field in all directions.

[0096] like Figure 5 As shown, in one embodiment, a filter module 600 electrically connected to the three-axis magnetic sensor module 100 and the differential signal circuit 210 is further included, and the filter module 600 is used to filter the voltage signal.

[0097] In this embodiment, it should be noted that the main function of the filter module 600 is to filter the voltage signal transmitted from the three-axis magnetic sensor module 100 through the differential signal circuit 210. During the magnetic field measurement process, the three-axis magnetic sensor will capture the weak magnetic field signal and convert it into an electrical signal (usually a voltage signal) for transmission. However, these electrical signals are often mixed with various noises and interferences, such as electromagnetic interference, thermal noise, power supply fluctuations, etc., which will affect the accuracy of the measurement.

[0098] The filter module 600 first receives the voltage signal from the three-axis magnetic sensor module 100 after being processed by the differential signal circuit 210; the differential signal circuit 210 itself may have performed some preliminary processing on the signal, such as amplification, differentiation, etc., to improve the signal's anti-interference ability. Then, the filter module 600 performs filtering on the received voltage signal; the purpose of filtering is to remove or weaken the noise and interference components in the signal while retaining useful magnetic field information; the filtering operation may include low-pass filtering, high-pass filtering, band-pass filtering or band-stop filtering, etc. The specific filtering method selected depends on the characteristics of the signal and the frequency distribution of the noise. After filtering, the filter module 600 outputs a cleaner and more accurate voltage signal, which can be further processed and analyzed to obtain the final magnetic field measurement result.

[0099] In one embodiment, a power supply module electrically connected to the three-axis magnetic sensor module 100 , the signal processing circuit module 200 and the control module 300 is also included.

[0100] In this embodiment, it should be noted that the main function of the power module is to provide stable and reliable power for the entire measuring instrument. It needs to convert the external power supply (such as alternating current or direct current) into voltage and current suitable for the operation of each module.

[0101] In one embodiment, the magnetic induction intensity includes x-axis intensity, y-axis intensity, and z-axis intensity.

[0102] In this embodiment, it should be noted that the QMC5883 Hall element can provide magnetic induction intensity in three directions of x, y, and z axes, providing support for subsequent vector synthesis and other three-dimensional data processing processes.

[0103] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0105] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A digital weak magnetic field measuring instrument based on a three-axis magnetic sensor, characterized in that: It includes a three-axis magnetic sensor module, a signal processing circuit module, a control module and a magnetic field wave oscilloscope module; wherein, The three-axis magnetic sensor module is used to sense a weak magnetic field and generate a magnetic induction intensity signal, wherein the magnetic induction intensity signal is represented by a voltage signal; The signal processing circuit module includes a differential signal circuit, an amplifying circuit and an analog-to-digital conversion circuit, wherein the differential signal circuit is used to receive a voltage signal and form a differential signal, the amplifying circuit is used to receive the differential signal and amplify the differential signal to an analog signal within a preset voltage range, and the analog-to-digital conversion circuit is used to receive the analog signal and convert the analog signal into a digital signal; The control module includes a bottom surface parameter position solving module, a z-axis parameter position solving module and a vector cube module, wherein the bottom surface parameter position solving module is used to establish a plane 45-degree oblique coordinate system and solve the coordinate parameter position of the bottom surface rectangle located in the plane 45-degree oblique coordinate system according to the digital signal, the z-axis parameter position solving module is used to solve the coordinate parameter position of the z-axis according to the digital signal and the parameter position of each point of the bottom surface rectangle, and the vector cube module is used to synthesize the magnetic field vector according to the coordinate parameter position of the bottom surface rectangle and the coordinate parameter position of the z-axis; The magnetic field wave oscilloscope module is used to obtain and display the magnetic field waveform according to the magnetic field vector.

2. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1 is characterized in that: The bottom surface parameter position solving module includes a coordinate system establishing unit and a vector bottom surface solving unit. The coordinate system establishing unit is used to establish a 45-degree oblique coordinate system in the plane. The vector bottom surface solving unit is used to obtain the x-axis component and the y-axis component according to the digital signal and solve the coordinate parameter position of the bottom surface rectangle located in the 45-degree oblique coordinate system in the plane according to the x-axis component and the y-axis component.

3. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 2 is characterized in that: The z-axis parameter bit solution module includes a z-axis component acquisition unit and a copy offset unit, wherein the copy offset unit is used to acquire the z-axis component according to the digital signal, and the copy offset unit is also used to copy and offset the coordinate parameter bit of the bottom rectangle according to the z-axis component and form the coordinate parameter bit of the z-axis.

4. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1 is characterized in that: It also includes a self-test magnetic field generation module, which includes two coil bodies and a constant current input unit. The constant current input unit is used to connect the coil bodies according to a preset current value. The two coil bodies are used to generate a weak magnetic field after being connected and are sensed by the three-axis magnetic sensor module.

5. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 4 is characterized in that: The control module also includes a calculation module and an adjustment module. The calculation module is used to obtain a theoretical magnetic field size according to a magnetic field calculation model including a first correction parameter. The adjustment module is used to adjust the first correction parameter according to the magnetic field vector and the theoretical magnetic field size and obtain a second correction parameter.

6. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 5 is characterized in that: The magnetic field calculation model is expressed as: in, B is the theoretical magnetic field size, N is the number of turns of the coil body, I is the preset current value, μ0 is the vacuum magnetic permeability, R is the coil radius, x is the center distance between the two coil bodies, and α1 is the first correction parameter.

7. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1 is characterized in that: It also includes a human-computer interaction interface, which is used to display the magnetic field vector.

8. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1, characterized in that: It also includes a filter module electrically connected to the three-axis magnetic sensor module and the differential signal circuit, and the filter module is used to filter the voltage signal.

9. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1, characterized in that: It also includes a power supply module electrically connected to the three-axis magnetic sensor module, the signal processing circuit module and the control module.

10. The digital weak magnetic field measuring instrument based on a three-axis magnetic sensor according to claim 1, characterized in that: The magnetic induction intensity includes x-axis intensity, y-axis intensity and z-axis intensity.

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