JP6346466B2 - Magnetic data correction device - Google Patents

Description

The present invention relates to a magnetic data correction equipment, and more particularly relates to the acquired magnetic data correction equipment capable of magnetic data removing accurately the influence of the soft iron effect.

Conventionally, a compass sensor has been widely used as a means for sensing the traveling direction of an electronic device that travels in a certain direction, such as a mobile terminal or a moving body such as an automobile.
This type of compass sensor can measure the direction (azimuth angle) of geomagnetism by detecting a weak magnetic field existing on the earth. However, some compass sensors used in electronic equipment may cause an error in the measured azimuth angle due to the influence of ferromagnetic components mounted in the surrounding area. For example, hard magnetic parts having a large holding force such as speakers and magnetized hinge parts give a strong magnetic field (offset magnetic field) to the surroundings. The phenomenon of applying an offset magnetic field around the hard magnetic material is called a hard iron effect.

  FIG. 1 is a schematic diagram for explaining the hard iron effect, and shows a locus of output values when the compass sensor that has received the hard iron effect rotates on the XY plane. It can be seen that the center of the output circle is shifted from the origin because the compass sensor is given an offset magnetic field. If the compass sensor observes a magnetic field that combines geomagnetism and offset magnetic field due to the hard iron effect, the correct azimuth angle cannot be obtained. However, the influence of the hard iron effect can be removed by using, for example, the offset magnetic field estimation technique described in Patent Document 1.

On the other hand, soft magnetic parts with high relative permeability such as magnetic sheets and SUS (stainless steel) sheet metal, which are widely used in portable terminals in recent years, also contribute to the azimuth error of the compass sensor. Soft magnetic materials have the property of distorting the surrounding magnetic field, and this phenomenon is called the soft iron effect.
FIG. 2 is a schematic diagram for explaining the soft iron effect in the vicinity of the soft magnetic component, and is a simulation diagram showing the soft iron (SI) effect by the soft magnetic component. A central rectangle represents a soft magnetic component, and a broken line represents a magnetic field line. It can be seen that the lines of magnetic force in the vicinity of the soft magnetic component are bent so as to be attracted to the soft magnetic component.

  FIG. 3 is a schematic diagram for explaining the soft iron effect, and shows a locus of output values when the compass sensor that has received the soft iron effect rotates on the XY plane. It can be seen that the output circle changes from a perfect circle to an ellipse due to the influence of the magnetic flux attracted to the soft magnetic component. If the compass sensor measures the geomagnetism bent by the soft iron effect, the correct azimuth angle cannot be obtained. In an electronic device in which each component such as a portable terminal is mounted in a very close state, the compass sensor azimuth error due to the influence of the soft magnetic component as described above is a big problem.

  Therefore, when a compass sensor mounted on a portable terminal or the like is under the influence of a soft iron effect caused by a nearby soft magnetic component, it is necessary to correct the data acquired by the sensor in order to obtain an accurate azimuth angle. . For example, Patent Document 2 proposes a distortion calculation method and apparatus for calibrating compass sensor data by introducing a distortion factor and a calibration quality level. The strain calculation method includes (a) a step of acquiring magnetic force data acquired by a compass sensor composed of a biaxial magnetic force field while rotating the compass sensor by 360 degrees, and (b) generated by the acquired data. Fitting the form with an elliptic function, (c) converting the acquired data and the fitted elliptic function into a circle centered at the origin, and (d) the main axis of the elliptic function or the acquired data on the horizontal axis. And a step of calculating a distortion rate indicating a degree of distortion of the magnetic field using an angle inclined with respect to the magnetic field.

JP-T-2004-517329 JP 2008-76397 A

The magnitude of magnetism acquired by the compass sensor may change depending on the state of the device on which the compass sensor is mounted.
4 (a) and 4 (b) are graphs illustrating the difference in the influence of the soft iron effect that accompanies the state, and a clamshell mobile phone equipped with a compass sensor is rotated in a geomagnetic environment. The locus of the output value of the compass sensor when operated is shown. FIG. 4A shows a state where the casing is closed, and FIG. 4B shows a state where the casing is opened.

  Since the influence of the soft iron effect received by the compass sensor differs between the closed state as shown in FIG. 4A and the opened state as shown in FIG. Does not match. Since the above-mentioned Patent Document 2 does not consider the state of a device on which a compass sensor is mounted, there is a problem that correction accuracy is poor. In addition, since the state of the device on which the compass sensor is mounted is not taken into account, there is a problem that a correction operation must be performed every time the state of the device changes.

The present invention has been made in view of such problems, it is an object to provide the acquired magnetic data correction equipment capable of magnetic data removing accurately the influence of the soft iron effect was It is in.

  The present invention has been made in order to achieve such an object. The invention according to claim 1 is directed to obtaining magnetic data obtained from an n-axis magnetic detector (20) (n is an integer of 2 or more). In the magnetic data correction device (3) to be corrected, the magnetic data acquisition unit (22) that acquires the magnetic data and the state information that indicates the state of the electronic device in which the magnetic data correction device (3) is mounted A state information acquisition unit (23) that acquires the state information from the information output unit (33), and the distribution shape obtained by distributing the state information and the magnetic data on the coordinate space of the n-axis is an n-dimensional sphere. Based on the state information acquired by the correction parameter information storage unit (25) for storing a plurality of correction parameter information associated with the correction parameter for correcting to the state information acquired by the state information acquisition unit (23), A correction parameter information selection unit (24) for selecting correction parameter information from among a plurality of correction parameter information stored in the positive parameter information storage unit (25), and a correction parameter selected by the correction parameter information selection unit (24) And a magnetic data correction unit (26) for correcting the magnetic data using a correction parameter included in the information.

According to a second aspect of the present invention, in the first aspect of the invention, the magnetic data correction unit (26) is a soft magnet that exists around the magnetic detection unit (20) included in the magnetic data. The correction is performed to remove the influence of the body from the magnetic data.
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the state information output unit includes a physical quantity detection unit that detects a physical quantity, and the state based on an output of the physical quantity detection unit. It is characterized by outputting information.

  The invention according to claim 4 is the invention according to claim 3, wherein the state information includes information on arrangement of members constituting the electronic device, information on a distance between members constituting the electronic device, At least one selected from the group consisting of information on the angle between members constituting the electronic device, information on stress applied to the member constituting the electronic device, information on the temperature of the electronic device, and information on the humidity of the electronic device It is characterized by being information.

The invention according to claim 5 is the invention according to claim 3 or 4, wherein the physical quantity detection unit includes an acceleration sensor, an angle sensor, an angular velocity sensor, a magnetic sensor, a stress sensor, a temperature sensor, a humidity sensor, and an optical sensor. It is at least one sensor selected from the group consisting of a sensor and an ultrasonic sensor.
The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the state information output unit outputs information on the magnitude of a magnetic field applied to the electronic device, and The correction parameter information selection unit selects the correction parameter information based on the state information and information on the magnitude of the magnetic field.

The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein an average value of each correction parameter for a plurality of electronic devices of the same state and the same type is used as the correction parameter. It is characterized by that.
The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the magnetic data correction section (26) is controlled by a microprocessor.

The invention according to claim 9 is the invention according to claim 8, characterized in that the correction parameter information storage unit (25) and the magnetic data correction unit (26) are controlled by different microprocessors. To do.
According to a tenth aspect of the present invention, in the ninth aspect of the invention, the driving frequency of the microprocessor that manages the correction parameter information storage unit (25) is fa, and the magnetic data correction unit (26) is managed. When the driving frequency of the microprocessor is fb, fa and fb satisfy the relationship of fa> fb.

The invention of claim 1 1, a computer, Ru program der to function as a magnetic data correction device according to any one of claims 1 to 10.

According to the present invention, it is possible to realize the acquired magnetic data correction equipment capable of magnetic data removing accurately the influence of the soft iron effect was.

It is a schematic diagram for demonstrating a hard iron effect. It is a schematic diagram for demonstrating the soft iron effect of the vicinity of a soft-magnetic component. It is a schematic diagram for demonstrating a soft iron effect. It is a figure which shows the graph data explaining the difference of the influence of the soft iron effect in the case of a state. It is a block block diagram for demonstrating embodiment of the magnetic data correction apparatus which concerns on this invention. It is the schematic diagram explaining the specific example of the state of an electronic device. It is a block block diagram for demonstrating the Example of the correction parameter creation apparatus of the magnetic data used with the magnetic data correction apparatus which concerns on this invention. It is a figure which shows the flowchart for demonstrating the magnetic data correction method which concerns on this invention. It is a figure which shows the flowchart for demonstrating the correction parameter creation method of the magnetic data used with the magnetic data correction method which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 5 is a block diagram for explaining an embodiment of the magnetic data correction apparatus according to the present invention. In the figure, reference numeral 3 denotes a magnetic data correction device, 20 a magnetic detection unit, 21 an error cause, 22 a magnetic data acquisition unit, 23 a state information acquisition unit, 24 a correction parameter selection unit, 25 a correction parameter information storage unit, Reference numeral 26 denotes a magnetic data correction unit, 27 denotes a correction data output unit, and 33 denotes a state information output unit.

The state information acquisition unit 23 is connected to a state information output unit 33 that outputs state information indicating the state of the electronic device in which the magnetic data correction device 3 is mounted. Reference numeral 32 denotes a correction parameter output unit of a correction parameter creation device, which will be described later with reference to FIG. A symbol P indicates a measurement target of the magnetic detection unit 20.
The magnetic data correction device 3 of the present invention is a magnetic data correction device that corrects magnetic data obtained from the magnetic detection unit 20 that detects magnetism. The magnetic detection unit 20 is connected to a magnetic data acquisition unit 22, and the magnetic data acquisition unit 22 is connected to a magnetic data correction unit 26. On the other hand, the state information acquisition unit 23 is connected to a correction parameter information selection unit 24, the correction parameter information selection unit 24 is connected to a correction parameter information storage unit 25, and the correction parameter information storage unit 25 is connected to a magnetic data correction unit 26. It is connected. The magnetic data correction unit 26 is connected to a correction data output unit 27.

  That is, the magnetic data acquisition unit 22 acquires the magnetic data output from the magnetic detection unit 20. The correction parameter information storage unit 25 receives a correction parameter output for each state of the electronic device or the like from the correction parameter output unit 32 in the correction parameter generation device described in FIG. A plurality of correction parameter information associated with correction parameters for correcting data are stored.

  As described above, when the magnetic data obtained from the n-axis magnetic detection unit 20 is distributed on the n-axis coordinate space, a soft magnetic material exists around the magnetic detection unit 20. The distribution shape is an n-dimensional ellipsoid. The correction parameter is a parameter for correcting the distribution shape to an n-dimensional sphere, and is a parameter for removing the influence of the soft magnetic material included in the magnetic data.

The status information acquisition unit 23 acquires status information indicating the status of the electronic device in which the magnetic data correction device 3 is mounted from the status information output unit 33. Further, the correction parameter information selection unit 24 selects correction parameter information from among a plurality of correction parameter information stored in the correction parameter information storage unit 25 based on the state information acquired by the state information acquisition unit 23.
Based on the correction parameter selection command selected by the correction parameter information selection unit 24, the magnetic data correction unit 26 corrects the magnetic data using the correction parameters included in the correction parameter information stored in the correction parameter information storage unit 25. Then, the corrected magnetic data is output to the correction data output unit 27.

  In this way, the correction parameter information storage unit 25 stores correction parameter information in which the state of the electronic device on which the magnetic data correction device is mounted and the correction parameter for correcting the magnetic data are associated with each other. The magnetic data acquisition unit 22 acquires the magnetic data affected by the error cause 21. The state information acquisition unit 23 detects the state of the electronic device and notifies the correction parameter selection unit 24.

The correction parameter selection unit 24 selects a magnetic data correction parameter suitable for the notified state from the correction parameter information storage unit and notifies the magnetic data correction unit 26. The magnetic data correction unit 26 applies the correction parameter selected by the correction parameter selection unit 24 to the acquired magnetic data. The correction data output unit 27 outputs magnetic data to which the correction parameter is applied.

The measurement object P represents a magnetic field that exists in nature or a magnetic field generated by a magnetic field generating means, and specifically corresponds to geomagnetism or the like. The magnetic data correction device 3 of the present invention is mounted on an electronic device such as a smartphone or a tablet terminal.
The magnetic data acquisition unit 22 acquires the magnetic data output from the magnetic detection unit 20. A specific example of the magnetic detection unit 20 is a compass sensor that detects geomagnetism. The error cause 21 interferes with the measurement target P and causes an error in the magnetic data acquired by the magnetic data acquisition unit 22. Specifically, a soft magnetic material affected by the soft iron effect corresponds to the error cause 21.

By the way, as shown in FIG. 4, the influence of the soft iron effect varies depending on the arrangement of the members constituting the electronic apparatus, the distance between the members, and the angle.
In addition, it is known that the magnetic properties of ferromagnetic materials including soft magnetic materials change depending on the temperature. For example, ferrite generally increases in permeability with increasing temperature, and after reaching a maximum value at a certain temperature, it starts to decrease. When the temperature further rises and reaches the Curie temperature, the permeability becomes 1 and the magnetism is increased. It has the property of disappearing. Some types of ferromagnets have a wide variety of temperature characteristics, such as the magnetic permeability decreasing in proportion to the temperature rise. That is, the influence of the soft iron effect received by the compass sensor varies depending on the temperature.

In addition, soft magnetic sheets that are often used for high-frequency noise countermeasures for electronic devices, short-range wireless communication, wireless charging, etc. may expand and contract depending on temperature and humidity. As a result, the influence of the soft iron effect on the compass sensor is different.
In addition, when the soft magnetic parts used in the housing are deformed by stress due to strong pressing or gripping of the housing of the electronic device, the compass sensor changes due to the positional relationship between the compass and the soft magnetic components changing. The effect of the soft iron effect on is different. In addition, some magnetic materials cause a billiary effect in which the magnetic permeability is changed by receiving stress, and the effect of the soft iron effect received by the compass sensor differs depending on this billily effect.

In addition, when a certain or higher magnetic field is applied to the soft magnetic parts constituting the electronic device, the soft magnetic parts cause magnetic saturation. As the magnetic permeability changes accordingly, the influence of the soft iron effect received by the compass sensor differs.
The state information output unit 33 includes, for example, the arrangement of members constituting the electronic device, the distance and angle between the members constituting the electronic device, the stress applied to the member constituting the electronic device, the temperature and humidity of the electronic device, and the electronic device. Status information indicating the status of the electronic device such as whether or not the constituent members are magnetically saturated is output.

  The state information output unit 33 includes a physical quantity detection unit that detects a physical quantity, and calculates and outputs state information based on the output of the physical quantity detection unit. The physical quantity detection unit detects physical quantities such as angles, angular velocities, accelerations, magnetism, temperature, humidity, stress, light intensity, and ultrasonic intensity. As the physical quantity detection unit, for example, an acceleration sensor, an angle sensor, an angular velocity sensor, a magnetic sensor, a temperature sensor, a humidity sensor, a stress sensor, an optical sensor, an ultrasonic sensor, or the like can be used.

The positional relationship such as the arrangement of members constituting the electronic device and the distance and angle between the members constituting the electronic device can be detected by using, for example, a magnetic field generation source and a magnetic detection unit. Specifically, it can be detected by attaching a magnetic field generation source such as a magnet to a member constituting the electronic apparatus and detecting the magnitude of the magnetic field generated from the magnetic field generation source.
Similarly, by using a light generation source and an optical sensor or an ultrasonic generation source and an ultrasonic sensor, it is possible to detect the arrangement of members constituting the electronic device and the distance and angle between the members constituting the electronic device.

The angle between members constituting the electronic device can also be detected by an acceleration sensor. Specifically, the angle formed by the members can be calculated by attaching an acceleration sensor to the member for measuring the angle and detecting the inclination angle of the member with respect to the direction of gravity.
Whether or not the magnetic saturation is achieved can be detected by using, for example, a magnetic detection unit. Specifically, whether the magnetic saturation has occurred by determining whether or not the magnitude of the magnetic field applied to the soft magnetic component is equal to or greater than a value that causes the magnetic saturation of the soft magnetic component. Can be detected.

As will be described later, since the optimum correction parameter varies greatly depending on the state of the electronic device on which the magnetic data correction device 3 is mounted, the magnetic data can be accurately corrected by properly using the correction parameter depending on the state of the electronic device. It becomes.
In addition, the magnetic data correction unit 26 performs correction to remove the influence of soft magnetic components existing around the magnetic detection unit included in the magnetic data from the magnetic data.

Further, as a correction parameter, an average value of correction parameters for a plurality of electronic devices in the same state and the same type is used. The magnetic data correction unit 26 is controlled by the microprocessor. The correction parameter information storage unit 25 and the magnetic data correction unit 26 are controlled by different microprocessors.
Further, when the driving frequency of the microprocessor managing the correction parameter information storage unit 25 is fa and the driving frequency of the microprocessor managing the magnetic data correction unit 26 is fb, fa and fb satisfy the relationship of fa> fb. ing.

  6A to 6E are schematic diagrams illustrating specific examples of states of electronic devices. As shown in FIGS. 6 (a) to 6 (e), the clamshell portable terminal is opened (FIG. 6 (b)), closed (FIG. 6 (a)), and the liquid crystal of the terminal at the hinge portion. FIG. 6C shows a state in which the part is reversed and closed (FIG. 6C), and a state in which the casing exceeds an arbitrary temperature (FIG. 6E). FIG. 6D shows a state of only the housing (normal state).

  For example, when the positional relationship between the magnetic detection unit and the soft magnetic component changes due to the movement of the casing such as a clamshell mobile phone, the influence of the soft iron effect also changes with the movement. FIG. 4 described above is a diagram illustrating a locus of an output value when the magnetic detection unit used in the clamshell type mobile phone is rotated in a geomagnetic environment, but the housing is closed. It can be seen that the traces drawn do not match in the open state. This is because the influence of the soft iron effect received by the compass sensor differs depending on the state of the mobile phone.

The correction parameter selection unit 24 selects a magnetic data correction parameter suitable for the state from the correction parameter information storage unit 25 based on the state information notified by the state information acquisition unit 23, and notifies the magnetic data correction unit 26.
In addition, the correction parameter information storage unit 25 stores and holds magnetic data correction parameters for each state created in advance. When the magnetic data acquisition unit 22 is a magnetic detection unit, SI correction parameters that match the state of the electronic device are stored in the correction parameter information storage unit 25.

The measured value obtained from the magnetic detection unit is the N-dimensional vector Hm, the magnetic field when there is no influence of the soft iron effect is the N-dimensional vector Ht, and the matrix representing the influence of the soft iron effect caused by the soft iron substance is the N-dimensional matrix G When the offset magnetic field is an N-dimensional vector O, the measured value Hm obtained from the magnetic detection unit is
Hm = G · Ht + O
It is represented by

Therefore, the magnetic field Ht when there is no influence of the soft iron effect is calculated by the following equation.
Ht = G- ¹ , Hm-G- ¹ , O
It is expressed.
Here, if the matrix G representing the influence of the soft iron effect and the offset magnetic field O are measured in advance, Ht can be calculated.

The magnetic data correction unit 26 loads the magnetic data correction parameter selected by the correction parameter selection unit 24 from the correction parameter information storage unit 25, and converts the acquired magnetic data into corrected magnetic data based on a predetermined calculation process. To do.
The correction data output unit 27 outputs the correction magnetic data calculated by the magnetic data correction unit 26. When the magnetic data is magnetic field data, the azimuth angle error due to the soft iron effect can be corrected by performing the azimuth calculation using the corrected magnetic field data to which the soft iron correction parameter is applied.

  In addition, by using the parameter that calculates the average value of the elements of the magnetic data correction parameter calculated from a plurality of electronic devices of the same model and the same state as the magnetic data correction parameter, it can be applied to all electronic devices of the same model and the same state. On the other hand, correction is possible. This eliminates the need to calculate a magnetic data correction parameter for each electronic device at the factory, and thus it is possible to correct a large amount of errors in the electronic device at a realistic cost.

  Further, the present invention can be controlled and implemented by a microprocessor or a microcontroller unit (hereinafter referred to as MCU) mounted on an electronic device. A microprocessor is an integrated circuit that integrates an arithmetic circuit, a control circuit, an input / output circuit, and the like on a single semiconductor chip to perform complex arithmetic operations and control external devices. It is used in a wide range of fields, including personal computers, mobile phones, calculators, watches, various home appliances, and various manufacturing equipment.

MCU is a type of microprocessor that emphasizes self-sufficiency and low cost compared to general-purpose microprocessors used in personal computers, etc., and includes a CPU core, memory for storing programs, one or more timers, and external peripherals. It consists of an input / output unit for communicating with the device.
With the recent increase in performance and functionality of mobile terminals, there has been an increase in power consumption of the microprocessor (hereinafter referred to as the main processor) that controls the entire system of the terminal and a decrease in processing capacity due to simultaneous execution of a large number of tasks. It has become a challenge. As one of responses to this problem, the processing is shared by using a plurality of MCUs, thereby distributing the load on the main processor and reducing the power consumption.

  For example, it is necessary to start a main processor with high power consumption every time magnetic data is acquired by various sensors by using a MCU that exclusively controls the sensor device to efficiently perform data processing using batch processing. Therefore, the time that the main processor stays in the idle state increases, and the power consumption of the entire terminal can be suppressed. Therefore, an MCU that exclusively controls the sensor device has a processing capability lower than that of the main processor and consumes less power.

Also in the present invention, the magnetic data correction unit 26 is controlled by the sensor device MCU, so that the magnetic data can be corrected with low power consumption. In addition, since the memory used by the MCU dedicated to the sensor device generally has a small capacity, it may be difficult to construct the correction parameter information storage unit 25 that stores a large amount of correction parameters on the MCU. In that case, the above-mentioned problem can be avoided by constructing the correction parameter information storage unit 25 on a large-capacity memory controlled by the main processor and controlling the magnetic data correction unit 26 on the MCU.

FIG. 8 is a flowchart for explaining the magnetic data correction method according to the present invention.
The magnetic data correction method of the present invention is a magnetic data correction method in the magnetic data correction device 3 for correcting magnetic data obtained from the magnetic detection unit 20 for detecting magnetism.
A step (S81) of acquiring magnetic data by the magnetic data acquisition unit 22, and a correction in which the state of the magnetic data correction device 3 is associated with the correction parameter for correcting the magnetic data by the correction parameter information storage unit 25. A step of storing a plurality of parameter information (S82), a step of detecting the state of the magnetic data correction device 3 by the state information acquisition unit 23 (S83), and a state of the magnetic data correction device 3 by the correction parameter information selection unit 24. Based on the correction parameter information selected from the plurality of correction parameter information stored in the correction parameter information storage unit 25 (S84), the correction selected by the correction parameter information selection unit 24 by the magnetic data correction unit 26 is performed. Step for correcting magnetic data using correction parameters included in parameter information (S85) and a.

In the step of correcting the magnetic data (S85), correction is performed to remove the influence of the soft magnetic material existing around the magnetic detection unit 20 included in the magnetic data from the magnetic data. In the state detection step (S83), it is detected that the positional relationship between any of the components constituting the magnetic data correction device 3 or the components attached to the magnetic data correction device 3 has changed.
The step of selecting correction parameter information (S84) selects the correction parameter information based on the size of the magnetic data. Further, as a correction parameter, an average value of each correction parameter for a plurality of electronic devices in the same state and the same type can be used.

The magnetic data correction unit 26 is controlled by the microprocessor. The correction parameter information storage unit 25 and the magnetic data correction unit 26 are controlled by different microprocessors.
Further, when the driving frequency of the microprocessor managing the correction parameter information storage unit 25 is fa and the driving frequency of the microprocessor managing the magnetic data correction unit 26 is fb, fa and fb satisfy the relationship of fa> fb. .

As described above, it is possible to realize a magnetic data correction method capable of accurately removing the influence of the soft iron effect from the acquired magnetic data.
The magnetic data correction program is a program for executing each step of the magnetic data correction method described above by a computer.
FIG. 7 is a block diagram for explaining a magnetic data correction parameter creation apparatus used in the magnetic data correction apparatus according to the present invention. In the figure, reference numeral 1 denotes an arbitrary magnetic field generator, 2 denotes an electronic device, 31 denotes a correction parameter creation unit, 32 correction parameter output unit, 120 denotes a magnetic detection unit, 121 denotes an error cause, and 122 denotes a magnetic data acquisition unit. The correction parameter output unit 32 is connected to the correction parameter information storage unit 25 in FIG. 5 described above.

The correction parameter creation device of the present invention includes a magnetic data acquisition unit 122 that acquires magnetic data from the magnetic detection unit 120, and a correction parameter generation unit 31 that is connected to the magnetic data acquisition unit 122 and the arbitrary magnetic field generation device 1. A correction parameter output unit 32 connected to the correction parameter creation unit 31 is provided.
The arbitrary magnetic field generator 1 means an arbitrary magnetic data generator that generates arbitrary magnetic data. Specifically, it is preferable to use a three-axis Helmholtz coil. The triaxial Helmholtz coil is a device that is composed of two concentric coils having the same diameter in the X, Y, and Z axis directions, and the distance between the coils is equal to the radius.

  Normally, the coil portion of the Helmholtz coil is a copper wire wound, and the magnetic field strength generated in the space between the two coils can be determined by measuring the current value flowing through the copper wire. Compared with ordinary coils, it is possible to generate a uniform magnetic field over a wider range and to generate a magnetic field with a strength that matches the theoretical value. It is often used to inspect the effects of magnetism.

The correction parameter creation unit 31 compares the magnitude of the magnetic data generated by the arbitrary magnetic field generator 1 with the value of the magnetic data acquired by the magnetic data acquisition unit 122, and calculates a magnetic data correction parameter.
When the measured value obtained from the magnetic detection unit is an N-dimensional vector Hm, a known magnetic field is an N-dimensional vector Ha, a matrix representing the influence of a soft iron effect by a soft magnetic material is an N-dimensional matrix G, and an offset magnetic field is an N-dimensional vector O. The measured value Hm obtained from the magnetic detection unit is
Hm = G · Ha + O
It is represented by

Accordingly, the matrix G representing the influence of the soft iron effect is calculated by the following equation.
G = (Hm-O) .Ha ^-1
If the offset magnetic field O is measured in advance, G can be calculated.
This is calculated for each state of the electronic device, and a correction parameter G- ¹ for each state of the electronic device is calculated.

The correction parameter output unit 32 outputs the magnetic data correction parameter created by the correction parameter creation unit 31. Of course, the magnetic data correction parameters used in the magnetic data correction device 3 are not limited to the correction parameters created by the correction parameter creation device shown in FIG.
That is, the correction parameter creation device of the present invention is a correction parameter creation device in a magnetic data correction device that corrects magnetic data obtained from the magnetic detection unit 120 that detects magnetism.

The correction parameter creation unit 31 compares the magnitude of the magnetic field generated by the arbitrary magnetic field generator 1 with the value of the magnetic data acquired by the magnetic data acquisition unit 121, and calculates a magnetic data correction parameter. The correction parameter output unit 32 outputs the magnetic data correction parameter created by the correction parameter creation unit 31.
In this way, it is possible to realize a correction parameter creation device that can accurately remove the influence of the soft iron effect from the acquired magnetic data.

FIG. 9 is a flowchart for explaining a magnetic data correction parameter creation method used in the magnetic data correction method according to the present invention.
The correction parameter creation method of the present invention is a correction parameter creation method in a magnetic data correction method for correcting magnetic data obtained from the magnetic detection unit 120 for detecting magnetism.
A step of calculating a magnetic data correction parameter by comparing the magnitude of the magnetic field generated by the arbitrary magnetic field generator 1 with the value of the magnetic data acquired by the magnetic data acquisition unit 121 by the correction parameter creation unit 31 (S91), and correction The parameter output unit 32 includes a step (S92) of outputting the magnetic data correction parameter created by the correction parameter creation unit 31.

In this way, it is possible to realize a correction parameter creation method capable of accurately removing the influence of the soft iron effect from the acquired magnetic data.
The correction parameter creation program is a program for executing each step of the above-described correction parameter creation method by a computer.

P Measurement object 1 Arbitrary magnetic field generator 2 Electronic device 3 Magnetic data correction device 20, 120 Magnetic detection unit 21, 121 Error cause 22, 122 Magnetic data acquisition unit 23 State information acquisition unit 24 Correction parameter selection unit 25 Correction parameter information storage unit 26 Magnetic Data Correction Unit 27 Correction Data Output Unit 31 Correction Parameter Creation Unit 32 Correction Parameter Output Unit 33 Status Information Output Unit

Claims (11)

In a magnetic data correction device for correcting magnetic data obtained from a magnetic detection unit of n (n is an integer of 2 or more) axis,
A magnetic data acquisition unit for acquiring the magnetic data;
A state information acquisition unit that acquires the state information from a state information output unit that outputs state information indicating a state of an electronic device in which the magnetic data correction device is mounted;
Correction that stores a plurality of correction parameter information in which the state information and a correction parameter for correcting a distribution shape obtained by distributing the magnetic data on the coordinate space of the n-axis to an n-dimensional sphere are associated with each other A parameter information storage unit;
A correction parameter information selection unit that selects correction parameter information from a plurality of correction parameter information stored in the correction parameter information storage unit based on the state information acquired by the state information acquisition unit;
A magnetic data correction unit that corrects the magnetic data using a correction parameter included in the correction parameter information selected by the correction parameter information selection unit;
A magnetic data correction apparatus comprising:   The magnetic data correction unit according to claim 1, wherein the magnetic data correction unit performs correction to remove, from the magnetic data, an influence of a soft magnetic material existing around the magnetic detection unit included in the magnetic data. apparatus.   The magnetic data correction device according to claim 1, wherein the state information output unit includes a physical quantity detection unit that detects a physical quantity, and outputs the state information based on an output of the physical quantity detection unit. The state information is
Information on the arrangement of the members constituting the electronic device, information on the distance between the members constituting the electronic device, information on the angle between the members constituting the electronic device, information on the stress applied to the members constituting the electronic device The magnetic data correction device according to claim 3, wherein the magnetic data correction device is at least one information selected from the group consisting of information on the temperature of the electronic device and information on the humidity of the electronic device.   The physical quantity detection unit is at least one sensor selected from the group consisting of an acceleration sensor, an angle sensor, an angular velocity sensor, a magnetic sensor, a stress sensor, a temperature sensor, a humidity sensor, an optical sensor, and an ultrasonic sensor. The magnetic data correction apparatus according to claim 3 or 4.   The state information output unit outputs information regarding the magnitude of the magnetic field applied to the electronic device, and the correction parameter information selection unit selects the correction parameter information based on the state information and information regarding the magnitude of the magnetic field. The magnetic data correction apparatus according to claim 1, wherein the magnetic data correction apparatus is selected.   7. The magnetic data correction apparatus according to claim 1, wherein an average value of each correction parameter for a plurality of electronic devices of the same state and the same type is used as the correction parameter.   8. The magnetic data correction apparatus according to claim 1, wherein the magnetic data correction unit is controlled by a microprocessor. 9. The magnetic data correction apparatus according to claim 8, wherein the correction parameter information storage unit and the magnetic data correction unit are controlled by different microprocessors. When the driving frequency of the microprocessor that manages the correction parameter information storage unit is fa and the driving frequency of the microprocessor that manages the magnetic data correction unit is fb, fa and fb are:
fa> fb
The magnetic data correction apparatus according to claim 9, wherein the relationship is satisfied. A program that causes a computer to function as the magnetic data correction device according to any one of claims 1 to 10 .

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