CN114859280A - A kind of calibration method of magnetic sensor array - Google Patents

Abstract

The invention provides a method for calibrating a magnetic sensor array. Put it into the three-axis Helmholtz coil, and ensure that the three axes of the magnetic sensor array and the three axes of the three-axis Helmholtz coil are parallel to each other; turn on the magnetic sensor array to start collecting data, and set the three-axis Helmholtz The magnetic fields of the three axes generated by the three-axis Helmholtz coil are all the first set magnetic field values, and the first output data of each magnetic sensor at this time are recorded; then the magnetic fields of the three axes generated by the three-axis Helmholtz coil are set to be the first value. 2. Set the magnetic field value, record the second output data of each magnetic sensor at this time; calculate the compensation parameter of the magnetic sensor according to the collected first output data and second output data of each magnetic sensor. Compared with the prior art, the present invention can completely calibrate the magnetic sensor array.

Description

A kind of calibration method of magnetic sensor array

【Technical field】

The invention relates to the technical field of magnetic sensors, in particular to a calibration method of a magnetic sensor array.

【Background technique】

Magnetic sensors can be used to test the magnetic field environment at a certain position in the space, but due to the small size of general magnetic sensors, the magnetic field environment that can be measured each time is relatively small. If you need to test a large range of magnetic fields, a single magnetic sensor It is completely impossible to cover, so there is a magnetic sensor array that puts more magnetic sensors on a PCB board to test the magnetic field environment of an area. For the magnetic sensor array, due to the inconsistency between the magnetic sensors and the inconsistency in the actual production process, it needs to be tested before using it as a tool to test the actual magnetic field environment. calibration.

[Content of the invention]

One of the objectives of the present invention is to provide a method for calibrating a magnetic sensor array, which can completely calibrate the magnetic sensor array.

According to one aspect of the present invention, the present invention provides a method for calibrating a magnetic sensor array, comprising: providing a triaxial Helmholtz coil; calibrating the triaxial Helmholtz coil to obtain the triaxial Helmholtz coil The sensitivity parameters of the magnetic field generated by the coil current of each axis of the Holtz coil; put the magnetic sensor array into the three-axis Helmholtz coil, and ensure that the three axes of the magnetic sensor in the magnetic sensor array are consistent with The three axes of the three-axis Helmholtz coil are parallel to each other; the magnetic sensor array is turned on to start collecting data, and the magnetic fields of the three axes generated by the three-axis Helmholtz coil are set as the first setting Magnetic field value, record the output data of each magnetic sensor in the magnetic sensor array at this time, at this time, the output data of each magnetic sensor is called the first output data of the magnetic sensor; then set the three-axis Helmhol The magnetic fields of the three axes generated by the coil are all the second set magnetic field values, and the output data of each magnetic sensor in the magnetic sensor array at this time are recorded. At this time, the output data of each magnetic sensor is called the magnetic sensor's output data. the second output data, wherein the first set magnetic field value and the second set magnetic field value are opposite numbers to each other; according to the collected first output data and second output data of each magnetic sensor in the magnetic sensor array Compensation parameters of the magnetic sensor are calculated from the output data, and the compensation parameters are written into a file for saving, so as to call the compensation parameters when the magnetic sensor array is used subsequently.

Compared with the prior art, the present invention puts the magnetic sensor array into the three-axis Helmholtz coil, collects the output data of each magnetic sensor in the magnetic sensor array, calculates the compensation parameter of the magnetic sensor, and calculates the compensation parameters of the magnetic sensor. The compensation parameter is written into a file and saved, so that the compensation parameter can be called when the magnetic sensor array is used subsequently.

【Description of drawings】

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort. in:

FIG. 1 is a schematic structural diagram of a magnetic sensor array in one embodiment of the present invention;

2 is a schematic structural diagram of a three-axis Helmholtz coil in an embodiment of the present invention;

FIG. 3 is a flowchart of a method for calibrating a magnetic sensor array in one embodiment of the present invention.

【Detailed ways】

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Reference herein to "one embodiment" or "an embodiment" refers to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of "in one embodiment" in various places in this specification are not all referring to the same embodiment, nor are they separate or selectively mutually exclusive from other embodiments. Unless otherwise specified, the terms connected, connected, and connected herein mean electrically connected, all mean direct or indirect electrical connection.

Please refer to FIG. 1 , which is a schematic structural diagram of a magnetic sensor array in one embodiment of the present invention. The magnetic sensor array shown in FIG. 1 includes a Printed Circuit Board (PCB) board 110 and several magnetic sensors 120 , wherein the several magnetic sensors 120 are arranged in an M*N array on the PCB board 110 , wherein , N represents the number of columns, and M represents the number of rows.

Please refer to FIG. 2 , which is a schematic structural diagram of a three-axis Helmholtz coil in one embodiment of the present invention. The three-axis Helmholtz coil shown in FIG. 2 is used to generate a three-axis magnetic field, and includes three pairs of conductor coils, wherein the first pair of conductor coils are arranged in parallel along the X axis, and the second pair of conductor coils are parallel along the Y axis Arrangement, the third pair of conductor coils are arranged in parallel along the Z axis. In the embodiment shown in FIG. 2 , the conductor coil is a square-shaped conductor coil, and in another embodiment, the conductor coil can also be a circular-shaped conductor coil.

In order to completely calibrate the magnetic sensor array shown in Figure 1, it is necessary to select a suitable size of the three-axis Helmholtz coil shown in Figure 2, and its internal uniform area is required to be able to completely contain the coil shown in Figure 1. magnetic sensor array, and make a fixture (not shown) corresponding to the magnetic sensor array shown in FIG. 1 in the three-axis Helmholtz coil shown in FIG. It is fixed inside the three-axis Helmholtz coil shown in Figure 2 to ensure that after the magnetic sensor array shown in Figure 1 is placed in the three-axis Helmholtz coil shown in Figure 2, the magnetic sensor array shown in Figure 1 The three axes of the magnetic sensor 120 in FIG. 2 are parallel to the three axes of the three-axis Helmholtz coil shown in FIG. 2 .

Please refer to FIG. 3 , which is a flowchart of a method for calibrating a magnetic sensor array in one embodiment of the present invention.

The calibration method of the magnetic sensor array shown in FIG. 3 includes the following steps.

Step 310 , providing a three-axis Helmholtz coil as shown in FIG. 2 .

Step 320 , calibrating the three-axis Helmholtz coil shown in FIG. 2 to obtain the sensitivity parameters of the magnetic field generated by the current of each axis of the three-axis Helmholtz coil as shown in FIG. 2 . Specifically, first turn on the three-axis Helmholtz coil shown in Figure 2, and place a precise magnetometer inside the three-axis Helmholtz coil shown in Figure 2 to ensure that the three axes of the magnetometer are as far as possible. Parallel to the three axes of the three-axis Helmholtz coil as shown in Figure 2; by adjusting the current of the three-axis Helmholtz coil as shown in Figure 2, the outputs of the three axes of the magnetometer are adjusted is 0, the current of the three-axis Helmholtz coil shown in Figure 2 at this time is used as the offset offset of the magnetic field of the three-axis Helmholtz coil shown in Figure 2, thereby shielding the external geomagnetic field interference; adjust the current of the three-axis Helmholtz coil shown in Figure 2 again, and obtain the sensitivity parameter sensitivity of the magnetic field generated by the current of each axis coil through formula 1.

M=S*(C-offset) Equation 1

Among them, M is the output of the precise magnetometer; C is the current applied to the coil; S is the sensitivity of the magnetic field generated by the coil current; offset is the coil current offset.

Step 330: Put the magnetic sensor array shown in FIG. 1 into the three-axis Helmholtz coil shown in FIG. 2, and ensure the three axes of the magnetic sensor 120 in the magnetic sensor array shown in FIG. 1 The three axes of the three-axis Helmholtz coil shown in FIG. 2 are parallel to each other. In one embodiment, a fixture (not shown) corresponding to the magnetic sensor array shown in FIG. 1 is fabricated in the three-axis Helmholtz coil shown in FIG. It is fixed inside the three-axis Helmholtz coil shown in Figure 2 to ensure that after the magnetic sensor array shown in Figure 1 is placed in the three-axis Helmholtz coil shown in Figure 2, the magnetic sensor array shown in Figure 1 The three axes of the magnetic sensor 120 in FIG. 2 are parallel to the three axes of the three-axis Helmholtz coil shown in FIG. 2 .

Step 340: Turn on the magnetic sensor array shown in FIG. 1 to start collecting data, set the magnetic fields of the three axes generated by the three-axis Helmholtz coil shown in FIG. 2 as the first set magnetic field value, and record the current value at this time. The output data M11(X0, Y0, Z0), M12(X0, Y0, Z0)...Mmn(X0, Y0, Z0) of each (or all) magnetic sensor 120 in the magnetic sensor array as shown in FIG. 1 , at this time , the output data of each magnetic sensor 120 is referred to as the first output data of the magnetic sensor; and then the magnetic fields of the three axes generated by the three-axis Helmholtz coil shown in FIG. 2 are all set to the second set magnetic field value , record the output data M11 (X1, Y1, Z1), M12 (X1, Y1, Z1)... Mmn (X1, Y1, Z1) of each (or all) magnetic sensor 120 in the magnetic sensor array shown in FIG. 1 at this time ), at this time, the output data of each magnetic sensor 120 is called the second output data of the magnetic sensor, wherein the first set magnetic field value and the second set magnetic field value are opposite numbers to each other. That is, in the magnetic sensor array shown in FIG. 1 , the first output data of each magnetic sensor 120 is Mmn(X0, Y0, Z0), and the second output data of each magnetic sensor 120 is Mmn(X0 , Y0, Z0), where Mmn is the output data of the magnetic sensor 120 located at the mth column and the nth row in the magnetic sensor array as shown in FIG. 1 , where (X0, Y0, Z0) is as shown in FIG. 2 The three-axis magnetic fields generated by the three-axis Helmholtz coil are all three-axis magnetic fields at the first set magnetic field value; (X1, Y1, Z1) are generated by the three-axis Helmholtz coil as shown in Figure 2 The magnetic fields of the three axes are all the three-axis magnetic fields at the second set magnetic field value. In a preferred embodiment, the first preset magnetic field value is -1 Gauss, and the second preset magnetic field value is 1 Gauss; in other embodiments, the first preset magnetic field value and the second preset magnetic field value are The set magnetic field value can also be other values, as long as the first set magnetic field value and the second set magnetic field value are opposite numbers to each other.

Step 350: Calculate the collected first output data Mmn(X0, Y0, Z0) and second output data Mmn(X0, Y0, Z0) of each magnetic sensor 120 in the magnetic sensor array shown in FIG. 1 . The compensation parameters of the magnetic sensor 120 are written and saved in a file, so that the compensation parameters can be called when the magnetic sensor array is used subsequently.

The compensation parameters of the magnetic sensor 120 include offset offset and sensitivity sensitivity. In one embodiment, if the first preset magnetic field value is -1 Gauss, and the second preset magnetic field value is 1 Gauss, then

M11_offset(X,Y,Z)＝(M11(X1,Y1,Z1)+M11(X0,Y0,Z0))/2

M11_sensitivity(X,Y,Z)=(M11(X1,Y1,Z1)-M11(X0,Y0,Z0))/2

…

Mmn_offset(X,Y,Z)＝(Mmn(X1,Y1,Z1)+Mmn(X0,Y0,Z0))/2

Mmn_sensitivity(X, Y, Z)=(Mmn(X1, Y1, Z1)-Mmn(X0, Y0, Z0))/2.

That is to say, if the first preset magnetic field value is -1 Gauss, and the second preset magnetic field value is 1 Gauss, the calculation formula of the offset Mmn_offset of each magnetic sensor 120 is:

Mmn_offset(X,Y,Z)=(Mmn(X1,Y1,Z1)+Mmn(X0,Y0,Z0))/2;

The formula for calculating the sensitivity Mmn_sensitivity of each magnetic sensor 120 is:

Mmn_sensitivity(X, Y, Z)=(Mmn(X1, Y1, Z1)-Mmn(X0, Y0, Z0))/2.

To sum up, the method for calibrating the magnetic sensor array provided by the present invention can completely calibrate the magnetic sensor array.

In the present invention, "connected", "connected", "connected", "connected" and other words refer to electrical connection, and unless otherwise specified, refer to direct or indirect electrical connection.

The above descriptions are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, but any equivalent modifications or changes made by those of ordinary skill in the art according to the disclosure of the present invention shall be included in the rights. within the scope of protection stated in the request.

Claims (9)

1. A method of calibrating a magnetic sensor array, comprising:

providing a three-axis Helmholtz coil;

calibrating the triaxial Helmholtz coils to obtain sensitivity parameters of a magnetic field generated by each axial coil current of the triaxial Helmholtz coils;

putting the magnetic sensor array into the three-axis Helmholtz coil, and ensuring that three axes of the magnetic sensors in the magnetic sensor array are parallel to three axes of the three-axis Helmholtz coil;

starting the magnetic sensor array to start data acquisition, setting magnetic fields of three axes generated by the three-axis Helmholtz coil to be first set magnetic field values, and recording output data of each magnetic sensor in the magnetic sensor array at the moment, wherein the output data of each magnetic sensor is called as first output data of the magnetic sensor at the moment; setting the magnetic fields of the three axes generated by the three-axis Helmholtz coil to be second set magnetic field values, and recording output data of each magnetic sensor in the magnetic sensor array at the moment, wherein the output data of each magnetic sensor is called as second output data of the magnetic sensor, and the first set magnetic field value and the second set magnetic field value are opposite numbers;

and calculating a compensation parameter of each magnetic sensor according to the acquired first output data and second output data of the magnetic sensor in the magnetic sensor array, and writing the compensation parameter into a file for storage so as to call the compensation parameter when the magnetic sensor array is used subsequently.

2. The method of calibrating a magnetic sensor array of claim 1,

the step of calibrating the three-axis Helmholtz coil comprises:

starting the triaxial Helmholtz coil, and placing a magnetometer in the triaxial Helmholtz coil to ensure that three axes of the magnetometer are parallel to three axes of the triaxial Helmholtz coil;

adjusting the outputs of the three axes of the magnetometer to 0 by adjusting the currents of the three-axis Helmholtz coils, and taking the current of the three-axis Helmholtz coil at this time as the offset of the magnetic field of the three-axis Helmholtz coil;

adjusting the current of the three-axis Helmholtz coil again, obtaining the sensitivity parameter of the magnetic field generated by the current of each axis coil through a formula 1,

m ═ S (C-offset) formula 1

Wherein M is the output of the magnetometer; c is the current applied to the coil; s is the sensitivity of the magnetic field generated by the coil current; offset is the coil current offset.

3. The method of calibrating a magnetic sensor array of claim 1,

in the magnetic sensor array, the first output data of each magnetic sensor is Mmn (X0, Y0, Z0), the second output data of each magnetic sensor is Mmn (X1, Y1, Z1),

where Mmn is output data of the magnetic sensor located in the mth column and nth row in the magnetic sensor array, where (X0, Y0, Z0) is a three-axis magnetic field when all three-axis magnetic fields generated by the three-axis helmholtz coil are the first set magnetic field value; (X1, Y1, Z1) is the three-axis magnetic field for the second set magnetic field value for all three axes of the three-axis Helmholtz coil.

4. The method of calibrating a magnetic sensor array of claim 3,

the compensation parameters for each magnetic sensor include offset and sensitivity,

the offset value Mmn _ offset of each magnetic sensor is calculated by the formula

Mmn_offset(X,Y,Z)＝(Mmn(X1,Y1,Z1)+Mmn(X0,Y0,Z0))/2；

The sensitivity of each magnetic sensor is calculated by

Mmn_sensitivity(X,Y,Z)＝(Mmn(X1,Y1,Z1)-Mmn(X0,Y0,Z0))/2。

5. The method of calibrating a magnetic sensor array of claim 1,

the magnetic sensor array comprises a PCB board and a plurality of magnetic sensors,

the plurality of magnetic sensors are arranged on the PCB in an array form.

6. The method of calibrating a magnetic sensor array of claim 1,

the magnetic sensor array is placed in a uniform region inside the triaxial Helmholtz coil.

7. The method of calibrating a magnetic sensor array of claim 6,

a clamp corresponding to the magnetic sensor array is arranged in the triaxial Helmholtz coil,

the magnetic sensor array is fixed inside the triaxial Helmholtz coil by the clamp.

8. The method of calibrating a magnetic sensor array of claim 1,

the triaxial Helmholtz coil is used for generating a triaxial directional magnetic field,

the triaxial Helmholtz coil includes three pairs of conductor coils, wherein a first pair of conductor coils is arranged in parallel along an X axis, a second pair of conductor coils is arranged in parallel along a Y axis, and a third pair of conductor coils is arranged in parallel along a Z axis.

9. The method of calibrating a magnetic sensor array of claim 4,

the first set magnetic field value is-1 gauss, and the second set magnetic field value is 1 gauss.

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