Magnetic Small Module System Based on Triaxial Fluxgate Sensors

Abstract

The present invention discloses a magnetic small module system based on a three-axis fluxgate sensor, belonging to the field of magnetic induction detection. It includes a mounting plate. Four corners of the upper end of the mounting plate are respectively fixedly installed with three copper studs, and the four groups of the three copper studs are symmetric about the center axis of the mounting plate in pairs. A substrate is fixedly connected above the mounting plate through the three copper studs, and a connector is fixedly connected to the front end of the mounting plate. The present invention can realize the acquisition, internal storage and data reading of magnetic signals. An attitude sensor is added to detect the dynamic situation of the device. At the same time, the electronic hardware design meets the usage requirements and technical indicators, the structural design meets the technical indicator requirements, the power consumption is properly controlled, the continuous working time is long, and it has high practical value.

Description

Technical Field

[0001] The present invention relates to the field of magnetic induction detection, and particularly to a magnetic small module system based on a three-axis fluxgate sensor. Background Art

[0002] A fluxgate sensor is a sensor that measures weak magnetic fields by using the non-linear relationship between the magnetic induction intensity and the magnetic field intensity of a high-permeability iron core in an alternating magnetic field under the saturation excitation of the measured magnetic field. Compared with other types of magnetic measuring instruments, the fluxgate sensor has the characteristics of high resolution, wide range of weak magnetic field measurement, reliability, ability to directly measure the components of the magnetic field, and suitability for use in fast-moving systems. With the wide use of fluxgate sensors, magnetic small module systems based on domestic devices and existing three-axis fluxgate sensor products have also been widely studied and used by relevant field personnel;

[0003] The existing magnetic small module system cannot realize the acquisition, internal storage, and data reading of magnetic signals, has high power consumption, short working time, and its structural design cannot meet the technical index requirements. Therefore, we propose a magnetic small module system based on a three-axis fluxgate sensor. Summary of the Invention

[0004] The purpose of the present invention is to solve the defects existing in the prior art, and a magnetic small module system based on a three-axis fluxgate sensor is proposed.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A magnetic small module system based on a three-axis fluxgate sensor includes a mounting plate. Four copper studs III are respectively and fixedly installed at the four corners of the upper end of the mounting plate, and the four groups of copper studs III are symmetric about the center axis of the mounting plate in pairs. A substrate is fixedly connected above the mounting plate through the copper studs III, and a connector is fixedly connected to the front end of the mounting plate.

[0007] As a further solution of the present invention, a battery is movably connected to the upper end of the mounting plate. Four copper studs I are fixedly connected to the upper end of the substrate. A probe control circuit board is movably connected above the substrate through the copper studs I. A probe socket cavity is fixedly connected to the lower left corner of the upper end of the substrate. Three fluxgate probes are fixedly connected inside the probe socket cavity, and the three fluxgate probes are in a pairwise perpendicular and orthogonal positional relationship.

[0008] As a further solution of the present invention, the probe seat cavity is made of non-metallic engineering plastic material PSU, and three groups of holes are orthogonally distributed inside the probe seat cavity. There are two threaded holes at the bottom of the probe seat cavity for fixing the probe seat cavity on the substrate. The three groups of fluxgate probes can cooperate with the orthogonal holes without interfering with each other, and a cable outlet groove is reserved at one end. At the same time, the data collected by the three groups of fluxgate probes represent the X-axis magnetic field value, the Y-axis magnetic field value, and the Z-axis magnetic field value, respectively. The signal cable coming out of the probe seat cavity outlet groove is horizontally connected to the probe control circuit board to the right.

[0009] As a further solution of the present invention, the probe control circuit board adopts a double-layer board design made of FR-4 material and consists of two boards. The bottom and top layers of circuit PCB boards are connected by pin headers. During assembly, auxiliary tooling is used to ensure the spacing between layers. The top PCB has an outer dimension of 70.5×22mm. There are four through holes on the probe control circuit board, and there are four corresponding through holes on the substrate. The probe control circuit board is connected to the substrate through four copper studs, and the PCB design of the probe control circuit board complies with the general specifications for printed circuit boards GJB362-87, and the spacing between the bottom PCB and the top PCB is 2.5mm.

[0010] As a further solution of the present invention, an L-shaped bracket is fixedly connected to the upper left corner of the upper end of the substrate, and the three groups of side walls of the L-shaped bracket are respectively fixedly connected to four groups of copper studs 2, and the three groups of side walls of the L-shaped bracket are respectively movably connected to posture sensors through copper studs 2, and a data acquisition module is fixedly connected to the upper end of the substrate near the rear side.

[0011] As a further solution of the present invention, the two side surfaces and the step surface of the L-shaped bracket serve as mounting surfaces, which are orthogonal to each other. The three orthogonal mounting surfaces of the L-shaped bracket respectively have four threaded holes for fixing the posture sensor, and the bottom surface of the L-shaped bracket has four threaded holes corresponding to the four through holes on the substrate for installation and fixation.

[0012] As a further solution of the present invention, the specific model of the attitude sensor is the domestic MEMS acceleration sensor JFMZ, which adopts an integrated XYZ three-axis solution and is integrated on a circuit board together with a data acquisition module. The analog signal is output through the AD acquisition output of the single-chip microcomputer to calculate the overall attitude angle data of the product. The data acquisition module is designed using domestically produced chips.

[0013] As a further solution of the present invention, the connector is externally connected to a single-chip microcomputer, and the single-chip microcomputer is used to issue acquisition instructions and process the acquired data. The specific processing steps are as follows:

[0014] Step 1: The staff sets the serial port interrupt for the single-chip microcomputer. When the single-chip microcomputer receives the sending instruction from the host computer, the interrupt is triggered and it enters the interrupt service function to wait for the host computer to send the RTC initialization time.

[0015] Step 2: After receiving the initialization time sent by the host computer, the single-chip microcomputer parses it into the BCD code format required for RTC initialization to initialize the RTC. After the initialization is completed, the single-chip microcomputer sends a message to the host computer indicating that the RTC initialization is completed.

[0016] Step 3: The three groups of fluxgate probes and the attitude sensor use the timer as the time reference. When the fluxgate probes collect magnetic signals for a period of time, the attitude sensor collects attitude data once, and then packs and stores the magnetic signals and attitude information. At the same time, the current attitude data is used as the attitude information of the magnetic small module during this period, and this process repeats.

[0017] Step 4: Mount the SD card and obtain the current RTC time. Then, use the RTC time as the file name to create a csv format file to write the file header. Then, in ascending order, they are the time stamp, the magnetic field value on the X-axis, the magnetic field value on the Y-axis, the magnetic field value on the Z-axis, and the pitch angle, roll angle, and heading angle related to the attitude angle of the magnetic small module, and write the data in the form of rows.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] In the present invention, the probe seat cavity is made of the non-metallic engineering plastic material PSU, and the three groups of fluxgate probes are encapsulated in three orthogonal holes in the probe seat cavity and sealed with glue. The single-chip microcomputer receives the initialization time sent by the host computer to initialize the RTC. After the initialization is completed, the three groups of fluxgate probes and the attitude sensor use the timer as the time reference. When the fluxgate probes collect magnetic signals for a period of time, the attitude sensor collects attitude data once, and then packs and stores the magnetic signals and attitude information. At the same time, the current attitude data is used as the attitude information of the magnetic small module during this period, and this process repeats. Then, mount the SD card and obtain the current RTC time. Then, use the RTC time as the file name to create a csv format file to write the file header. Then, in ascending order, they are the time stamp, the magnetic field value on the X-axis, the magnetic field value on the Y-axis, the magnetic field value on the Z-axis, and the pitch angle, roll angle, and heading angle related to the attitude angle of the magnetic small module, and write the data in the form of rows. It can realize the collection, internal storage, and data reading of magnetic signals. The attitude sensor is added to detect the dynamic situation of the device. At the same time, the electronic hardware design meets the use requirements and technical indicators, the structural design meets the technical indicator requirements, the power consumption is properly controlled, and the continuous working time is long, which has high practical value. Description of the Drawings

[0020] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention.

[0021] Figure 1 It is a schematic diagram of the overall structure of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention;

[0022] Figure 2 It is a side view of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention;

[0023] Figure 3 It is a system block diagram of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention;

[0024] Figure 4 It is a design block diagram of the data acquisition module of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention;

[0025] Figure 5 It is a front circuit design diagram of the data acquisition module of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention;

[0026] Figure 6 It is a reverse circuit design diagram of the data acquisition module of the magnetic small module system based on a three-axis fluxgate sensor proposed by the present invention.

[0027] In the figure: 1. mounting plate; 2. substrate; 3. probe control circuit board; 4. connector; 5. data acquisition module; 6. attitude sensor; 7. L-shaped bracket; 8. probe seat cavity; 9. fluxgate probe; 10. first copper stud; 11. second copper stud; 12. third copper stud; 13. battery. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0029] Referring to Figures 1 - 6 , the magnetic small module system based on a three-axis fluxgate sensor includes a mounting plate 1. Four copper studs three 12 are respectively and fixedly installed at the four corners of the upper end of the mounting plate 1, and the four groups of copper studs three 12 are symmetric about the center axis of the mounting plate 1 in pairs. A substrate 2 is fixedly connected above the mounting plate 1 through the copper studs three 12, and a connector 4 is fixedly connected to the front end of the mounting plate 1.

[0030] A battery 13 is movably connected to the upper end of the mounting plate 1, four groups of copper studs 10 are fixedly connected to the upper end of the base plate 2, a probe control circuit board 3 is movably connected to the upper side of the base plate 2 through the copper studs 10, a probe seat cavity 8 is fixedly connected to the lower left corner of the upper end of the base plate 2, three groups of fluxgate probes 9 are fixedly connected inside the probe seat cavity 8, and the three groups of fluxgate probes 9 are in a vertical and orthogonal position relationship with each other.

[0031] In this embodiment, the probe control circuit board 3 adopts a double-layer board design of FR-4 material, and is composed of two boards. The bottom and top layers of the PCB boards are connected by pin headers. The spacing between the layers is ensured by auxiliary tooling during assembly. The top PCB has an outer dimension of 70.5×22 mm. There are four through holes on the probe control circuit board 3, and there are four through holes on the substrate 2. The probe control circuit board 3 is connected to the substrate 2 through four copper studs, and the PCB design of the probe control circuit board 3 complies with the requirements of the GJB362-87 general specification for printed circuit boards. The spacing between the bottom PCB and the top PCB is 2.5 mm, and the probe seat cavity 8 is made of The material used is non-metallic engineering plastic material PSU, which has good heat resistance, no deformation and no aging when heated, and can remain stable at -100℃~+160℃. Three groups of holes are orthogonally distributed inside the probe seat cavity 8. There are two threaded holes at the bottom of the probe seat cavity 8, which are used to fix the probe seat cavity 8 on the substrate 2. The three groups of fluxgate probes 9 can cooperate with the orthogonal holes without interfering with each other, and a cable outlet groove is reserved at one end. At the same time, the data collected by the three groups of fluxgate probes 9 represent the X-axis magnetic field value, the Y-axis magnetic field value, and the Z-axis magnetic field value respectively. The signal cable coming out of the outlet groove of the probe seat cavity 8 is horizontally connected to the probe control circuit board 3 to the right.

[0032] An L-shaped bracket 7 is fixedly connected to the upper left corner of the upper end of the substrate 2, and four groups of copper studs 11 are fixedly connected to the three groups of side walls of the L-shaped bracket 7 respectively. The three groups of side walls of the L-shaped bracket 7 are movably connected to the posture sensor 6 through the copper studs 11 respectively, and a data acquisition module 5 is fixedly connected to the upper end of the substrate 2 near the rear side; the connector 4 is externally connected to a single-chip microcomputer, which is used to issue acquisition instructions and process the collected data.

[0033] It should be further explained that the two side surfaces and the step surface of the L-shaped bracket 7 serve as mounting surfaces, which are orthogonal to each other. The three orthogonal mounting surfaces of the L-shaped bracket 7 are respectively provided with four threaded holes for fixing the attitude sensor 6, and the bottom surface of the L-shaped bracket 7 has four threaded holes, corresponding to the four through holes on the substrate 2, which are used for installation and fixation. The specific model of the attitude sensor 6 is the domestic MEMS acceleration sensor JFMZ1002, which adopts an integrated XYZ three-axis solution and is integrated on the circuit board together with the data acquisition module 5. The analog signal is output through the AD acquisition output of the single-chip microcomputer to calculate the overall attitude angle data of the product. The data acquisition module 5 is designed with domestically produced chips.

[0034] Among them, it should be noted that, for example Figures 4 - 6 , the PCB wiring layout of the data acquisition module 5 strictly follows the General Specification for Printed Circuit Boards GJB362-87. Based on the data acquisition circuit structure and reliability design requirements, when all structural elements are met, it follows the principles of good electromagnetic compatibility, balanced and reasonable distribution of electronic components, clear outer frame and silk screen, maximized space utilization, and beautiful overall appearance. The shape parameters of its PCB board are strictly designed according to the data acquisition circuit structure. There are no relatively high components on the back, and all ports are given in the form of pins, and are connected to each sensor and the host computer in the form of DuPont wires.

[0035] Specifically, as Figure 3 shown, the staff sets the serial port interrupt for the single-chip microcomputer. When the single-chip microcomputer receives the sending instruction from the host computer, it triggers the interrupt and enters the interrupt service function, waiting for the host computer to send the RTC initialization time. After receiving the initialization time sent by the host computer, the single-chip microcomputer parses it into the BCD code format required for RTC initialization to initialize the RTC. After the initialization is completed, the single-chip microcomputer sends a message to the host computer indicating that the RTC initialization is completed. The three groups of fluxgate probes 9 and the attitude sensor 6 use the timer as the time reference. When the fluxgate probe 9 collects the magnetic signal for a period of time, the attitude sensor 6 collects the attitude data once, then packs and stores the magnetic signal and the attitude information, and at the same time takes the current attitude data as the attitude information of the magnetic small module during this period, and repeats this process; then mounts the SD card and obtains the current RTC time, and then uses the RTC time as the file name to create a file in csv format to write the file header, and then in ascending order are the time stamp, X-axis magnetic field value, Y-axis magnetic field value, Z-axis magnetic field value, and the pitch angle, roll angle, and heading angle related to the attitude angle of the magnetic small module, and writes the data in the form of rows.

[0036] Among them, it should be noted that what the operator needs to do includes: connecting the serial port, setting the baud rate to 9600; sending the "Set-time" instruction; sending the initialization time, and the time format is: year-month-day-hour-minute-second, separated by "-" in the middle; waiting for the initialization completion message, and the message is "RTC-set success". Then the RTC time can be set by oneself.

[0037] It should be further noted that the file headers are Time, MagX(nT), MagY(nT), MagZ(nT), AngX, AngY, and AngZ respectively.

[0038] It should be further noted that since the TTL serial port is connected to the watertight interface, the upper computer can directly display the data in real time by connecting the serial port directly to the upper computer. The data of the magnetic small module is stored in the SD card, and the SD card can also be accessed through USB to read the data. This process is realized through the FATFS file system and the USB communication protocol. After the single-chip microcomputer is reset, the SDIO interface and the USB interface for SD card communication are initialized. Before the acquisition starts, the required data files are established, the files are synchronized during the acquisition process, the files are closed after the acquisition is completed, and the USB is connected to the upper computer to read the files.

Claims

1. A magnetic small module system based on a three-axis fluxgate sensor, comprising a mounting plate (1), characterized in that, Four copper studs three (12) are respectively fixedly installed at the four corners of the upper end of the mounting plate (1), and the four groups of copper studs three (12) are axisymmetric about the center of the mounting plate (1) in pairs. A substrate (2) is fixedly connected above the mounting plate (1) through the copper studs three (12), and a connector (4) is fixedly connected to the front end of the mounting plate (1); A battery (13) is movably connected to the upper end of the mounting plate (1). Four groups of copper studs one (10) are fixedly connected to the upper end of the substrate (2). A probe control circuit board (3) is movably connected above the substrate (2) through the copper studs one (10). A probe seat cavity (8) is fixedly connected to the lower left corner of the upper end of the substrate (2). Three fluxgate probes (9) are fixedly connected inside the probe seat cavity (8), and the three groups of fluxgate probes (9) are in a pairwise perpendicular and orthogonal positional relationship; The probe seat cavity (8) is made of a non-metallic engineering plastic material PSU. Three groups of holes are orthogonally and staggeredly distributed inside the probe seat cavity (8). There are two threaded holes at the bottom of the probe seat cavity (8) for fixing the probe seat cavity (8) on the substrate (2). The three groups of fluxgate probes (9) can cooperate with the orthogonal holes without interfering with each other, and a cable outlet groove is reserved at one end. At the same time, the data collected by the three groups of fluxgate probes (9) respectively represent the X-axis magnetic field value, the Y-axis magnetic field value, and the Z-axis magnetic field value. The signal cable coming out of the outlet groove of the probe seat cavity (8) is connected horizontally to the right to the probe control circuit board (3); An L-shaped bracket (7) is fixedly connected to the upper left corner of the upper end of the substrate (2). Four groups of copper studs two (11) are respectively fixedly connected to the three side walls of the L-shaped bracket (7). Attitude sensors (6) are respectively movably connected to the three side walls of the L-shaped bracket (7) through the copper studs two (11). A data acquisition module (5) is fixedly connected to the upper end of the substrate (2) near the rear side.

2. The magnetic small module system based on a three-axis fluxgate sensor according to claim 1, characterized in that The probe control circuit board (3) is designed with a double-layer board made of FR-4 material and consists of two boards in total. The bottom layer and the top layer of the circuit PCB board are connected by socket pins. During assembly, the distance between layers is ensured by an auxiliary tooling. The outer dimension of the top layer PCB is 70.5×22 mm. There are four through holes on the probe control circuit board (3), and there are four corresponding through holes on the substrate (2). The probe control circuit board (3) is connected to the substrate (2) through four copper studs, and the PCB design of the probe control circuit board (3) complies with the requirements of the general specification for printed boards GJB362-87. The interval between the bottom layer PCB and the top layer PCB is 2.5 mm.

3. The magnetic small module system based on a three-axis fluxgate sensor according to claim 1, characterized in that, Two side faces and the step face of the L-shaped bracket (7) serve as mounting surfaces and are pairwise orthogonal. There are four threaded holes on each of the three orthogonal mounting surfaces of the L-shaped bracket (7) for fixing the attitude sensor (6), and there are four threaded holes on the bottom surface of the L-shaped bracket (7), corresponding to the four through holes on the substrate (2), for installation and fixation.

4. The magnetic small module system based on a three-axis fluxgate sensor according to claim 3, characterized in that, The specific model of the attitude sensor (6) is the domestic MEMS acceleration sensor JFMZ1002. It adopts an integrated X-Y-Z three-axis scheme and is integrated with the data acquisition module (5) on the circuit board. The analog signal is output through the AD acquisition of the single-chip microcomputer, and the attitude angle data of the whole product is calculated. The data acquisition module (5) is designed with all domestic chips.

5. The magnetic small module system based on a three-axis fluxgate sensor according to claim 1, characterized in that The external of the connector (4) is connected with a single-chip microcomputer, which is used to send acquisition instructions and process the acquired data. The specific processing steps are as follows: Step 1: The staff sets the serial port interrupt for the single-chip microcomputer. When the single-chip microcomputer receives the sending instruction from the upper computer, the interrupt is triggered and it enters the interrupt service function to wait for the upper computer to send the RTC initialization time. Step 2: After receiving the initialization time sent by the upper computer, the single-chip microcomputer parses it into the BCD code format required for RTC initialization to initialize the RTC. After the initialization is completed, the single-chip microcomputer sends a message to the upper computer indicating that the RTC initialization is completed. Step 3: The three groups of fluxgate probes (9) and the attitude sensor (6) use the timer as the time reference. When the fluxgate probe (9) acquires the magnetic signal for a period of time, the attitude sensor (6) acquires the attitude data once, and then packs and stores the magnetic signal and the attitude information. At the same time, the current attitude data is used as the attitude information of the magnetic small module during this period, and it repeats in a cycle. Step 4: Mount the SD card and obtain the current RTC time. Then use the RTC time as the file name to create a csv format file to write the file header. Then, in ascending order, they are the time mark, the X-axis magnetic field value, the Y-axis magnetic field value, the Z-axis magnetic field value, and the pitch angle, roll angle, and heading angle related to the attitude angle of the magnetic small module, and the data is written in the form of rows.

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