A magnetic ball calibration method and a magnetic ball calibration device

Abstract

This invention discloses a magnetic ball calibration method and a magnetic ball calibration device. The magnetic ball calibration method includes rotating a magnetic ball around a first axis by a first angle, acquiring detection data during the rotation process, and obtaining a zero-point position P0 where the magnetic field strength component of the magnetic ball is zero in the direction of a second axis based on the detection data; obtaining a calibration position of the magnetic ball based on the detection data and the zero-point position P0; and calibrating the magnetic ball based on the calibration position. When the magnetic ball is at the calibration position, its magnetic polarization direction coincides with the second axis; the first axis and the second axis are perpendicular to each other; the three-axis magnetic field components include an X-axis magnetic field component, a Y-axis magnetic field component, and a Z-axis magnetic field component; the direction of the Z-axis magnetic field component coincides with the direction of the second axis; and the direction of the Y-axis magnetic field component coincides with the direction of the first axis. According to the magnetic ball calibration method and magnetic ball calibration device of this invention, magnetic balls can be calibrated conveniently, quickly, and accurately.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic control and the technical field of capsule endoscopy, in particular to a magnetic ball calibration method and a magnetic ball calibration device. BACKGROUND

[0002] Capsule endoscopy can be actively controlled by an external magnetic control device to perform detailed and comprehensive examination. Compared with a tube endoscope, the capsule endoscope has the advantages of good comfort and low risk of cross infection, so that its popularity rate is continuously improved in clinical application.

[0003] For a magnetic control capsule endoscopy system, a permanent magnet (usually a magnetic ball) on an external magnetic control device is a core component for controlling the movement of the capsule endoscope. By controlling the posture and / or position of the magnetic ball to change the magnetic field, the capsule endoscope can realize corresponding translation, rotation and inversion movements according to the changed magnetic field. Moreover, the magnetic ball affects the posture of the capsule endoscope through the direction of the magnetic field. In actual use, the uncertainty of the direction of the magnetic field of the permanent magnet or the deviation of the magnetic pole position will cause a large error in the posture angle of the capsule endoscope, affecting the accuracy of the posture of the capsule endoscope, and further affecting the accuracy of information collection of the capsule endoscope. For the external magnetic control device of the capsule endoscope, the direction of the magnetic ball needs to be calibrated when in use.

[0004] In the prior art, a plurality of sensors are usually used to obtain magnetic field data to determine the direction of the magnetic ball. Although this method can accurately determine the direction of the magnetic ball, the process is complicated and the operation is complex, which is not conducive to wide application.

[0005] Therefore, it is desirable to have a more simple, convenient and accurate magnetic ball calibration method and magnetic ball calibration device. SUMMARY

[0006] In view of the above problems, the purpose of the present application is to provide a magnetic ball calibration method and a magnetic ball calibration device, so as to accurately, conveniently and quickly calibrate the magnetic ball.

[0007] According to an aspect of the present application, a magnetic ball calibration method is provided, comprising the following steps:

[0008] The magnetic ball rotates around a first axis by a first angle, and detection data of three-axis magnetic field components at a detection position in the rotation process is obtained, the first angle being greater than or equal to 180°;

[0009] According to the detection data, a zero point position P0 of the magnetic field strength component of the magnetic ball in the direction of a second axis is obtained;

[0010] According to the detection data and the zero point position P0, a calibration position of the magnetic ball is obtained;

[0011] calibrate the magnetic sphere according to the calibration position of the magnetic sphere;

[0012] wherein, when the magnetic sphere is at the calibration position, a magnetic polarization direction of the magnetic sphere coincides with the second axis;

[0013] the first axis and the second axis are perpendicular to each other;

[0014] the three-axis magnetic field component includes an X-axis magnetic field component, a Y-axis magnetic field component, and a Z-axis magnetic field component;

[0015] a direction of the Z-axis magnetic field component coincides with a direction of the second axis; and the Y-axis magnetic field component coincides with a direction of the first axis.

[0016] Preferably, obtaining, according to the detection data, a zero point position P0 at which a magnetic field strength component of the magnetic sphere in the direction of the second axis is zero includes:

[0017] obtaining a plurality of sets of detection data of changes in magnetic field strength at detection positions during rotation of the magnetic sphere around the first axis;

[0018] obtaining, according to the detection data, a magnetic field strength component in the direction of the second axis for each set of detection data;

[0019] determining whether the magnetic field strength component in the direction of the second axis is zero to obtain a zero point position P0 at which the magnetic field strength component in the direction of the second axis is zero.

[0020] Preferably, obtaining, according to the detection data, a zero point position P0 at which a magnetic field strength component of the magnetic sphere in the direction of the second axis is zero includes:

[0021] obtaining, according to the detection data, a position at which the magnetic field component in the direction of the second axis is close to zero as a near-zero point position P1;

[0022] using the near-zero point position P1 as the zero point position P0.

[0023] Preferably, obtaining, according to the detection data and the zero point position P0, the calibration position of the magnetic sphere includes:

[0024] determining a data direction of the zero point position P0 during rotation of the magnetic sphere around the first axis by a first angle;

[0025] obtaining, according to the data direction of the zero point position P0, the zero point position P0, and the detection data, a first calibration position V0 and a second calibration position H0 of the magnetic sphere.

[0026] Preferably, obtaining, according to the detection data and the zero point position P0, the calibration position of the magnetic sphere further includes:

[0027] when the data direction of the zero position P0 changes from positive to negative, the first calibration position V0 = a - 90° and the second calibration position H0 = - β;

[0028] when the data direction of the zero position P0 changes from negative to positive, the first calibration position V0 = a + 90° and the second calibration position H0 = 180° - β,

[0029] wherein the three-axis magnetic field components at the zero position P0 are (b xi , b yi , b zi );

[0030] a is an angle of rotation of the magnetic sphere when reaching the zero position P0;

[0031] β is an angle between the x-direction component b xi and the y-direction component b yi at the zero position P0.

[0032] According to another aspect of the present application, there is provided a magnetic sphere calibration device, the magnetic sphere having a magnetic pole along a main axis direction, comprising:

[0033] a first driving unit for driving the magnetic sphere to rotate by a first angle about a first axis;

[0034] a three-axis magnetic field sensor disposed adjacent to the magnetic sphere to obtain detection data of three-axis magnetic field components of the magnetic sphere at a detection position during rotation; and

[0035] a data processing unit connected to the three-axis magnetic field sensor to receive the detection data of the three-axis magnetic field components, to obtain a zero position at which a magnetic field strength in a second axis direction is zero at the detection position according to the detection data, and to obtain a calibration position of the magnetic sphere according to the detection data and the zero position P0, and to calibrate the magnetic sphere according to the calibration position of the magnetic sphere;

[0036] wherein the main axis coincides with the second axis when the magnetic sphere is at the calibration position;

[0037] the first axis and the second axis are perpendicular to each other;

[0038] the three-axis magnetic field components include an X-axis magnetic field component, a Y-axis magnetic field component and a Z-axis magnetic field component;

[0039] the direction of the Z-axis magnetic field component coincides with the direction of the second axis, and the Y-axis magnetic field component coincides with the direction of the first axis.

[0040] Preferably, the first angle is greater than or equal to 180°, or 200°.

[0041] Preferably, the data processing unit comprises:

[0042] a first processing unit, configured to:

[0043] According to the detection data, a magnetic field strength component in the second axis direction of each group of detection data is obtained, and it is determined whether the magnetic field strength component in the second axis direction is 0, so as to obtain a zero point position P0 at which the magnetic field strength component in the second axis direction is 0.

[0044] Preferably, the data processing unit comprises:

[0045] a first processing unit, configured to:

[0046] According to the detection data, a position at which a magnetic field component in the second axis direction is close to 0 is obtained as a near-zero point position P1;

[0047] The near-zero point position P1 is taken as the zero point position P0.

[0048] Preferably, the data processing unit comprises a second processing unit, configured to: determine a data direction of the zero point position P0 according to the detection data.

[0049] According to the zero point position P0, the data direction of the zero point position P0 and the detection data, a first calibration position V0 and a second calibration position H0 of the magnetic ball are obtained.

[0050] Preferably, the first axis or the second axis passes through the three-axis magnetic field sensor; and the detection position comprises a position at which the three-axis magnetic field sensor is located.

[0051] The magnetic ball calibration device and the magnetic ball calibration method according to the embodiments of the present application use one three-axis magnetic sensor to determine the direction of the magnetic ball, are simple to operate, and can conveniently, quickly and accurately calibrate the magnetic ball, thereby providing accurate basis for the judgment of the posture of the capsule endoscope.

[0052] The magnetic ball calibration device and the magnetic ball calibration method according to the embodiments of the present application realize the correction of the magnetic ball by detecting and analyzing the magnetic field value at the detection position, and are simple and convenient to operate.

[0053] The magnetic ball calibration device and the magnetic ball calibration method according to the embodiments of the present application can realize automatic correction when the magnetic ball is rotated by a certain angle, the correction process is convenient to control, and errors caused by human operation are avoided.

[0054] The magnetic ball calibration device and the magnetic ball calibration method according to the embodiments of the present application determine the calibration position of the magnetic ball according to the zero point position and the magnetic field value, can avoid errors caused by too small data resolution in detection, and improve the accuracy of the correction of the magnetic ball. BRIEF DESCRIPTION OF DRAWINGS

[0055] The above and other objects, features and advantages of the present application will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0056] Figure 1 A magnetic field distribution diagram of a magnetic sphere according to an embodiment of the present application is shown;

[0057] Figure 2 A perspective view of a magnetic sphere calibration device according to a first embodiment of the present application is shown;

[0058] Figure 3 A flowchart of a magnetic sphere calibration method according to a first embodiment of the present application is shown;

[0059] Figure 4 A flowchart of a magnetic sphere calibration method according to a second embodiment of the present application is shown;

[0060] Figure 5 A schematic diagram of a magnetic sphere after calibration according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0061] Various embodiments of the present application will be described hereinafter with reference to the accompanying drawings. In the drawings, like reference numerals indicate like elements. For the sake of clarity, each portion in the drawings is not drawn to scale. In addition, some portions of the drawings can not be shown to scale.

[0062] The specific embodiments of the present application will now be described in further detail with reference to the drawings and embodiments. In the following description, numerous specific details are described to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without these specific details.

[0063] It is to be understood that when a layer, region or element is referred to as being "on" or "above" another layer, region or element, it can be directly on or above the other layer, region or element or intervening layers or regions can also be present. In addition, it is to be understood that when a layer, region or element is referred to as being "beneath" or "below" another layer, region or element, it can be directly beneath or below the other layer, region or element or intervening layers or regions can also be present. Also, a layer, region, or element need not be contiguous to a surface to which it is referred, as the intervening regions can be present in various forms.

[0064] Figure 1 A magnetic field distribution diagram of a magnetic sphere 10 according to an embodiment of the present application is shown. As shown, the magnetic sphere 10 of the embodiment of the present application has a magnetic pole (magnetic field of a specific direction) in the direction of the main axis. The main axis coincides with the line connecting the N and S poles of the magnetic sphere and is a specific axis on the magnetic sphere. The magnetic sphere 10 according to the embodiment of the present application has an N pole and an S pole at both ends of a certain diameter. The magnetic field distribution of the magnetic sphere 10 is shown, for example, by a magnetic field distribution diagram. Figure 1 The magnetic field distribution diagram of the magnetic sphere 10 according to the embodiment of the present application is shown in FIG. 1. As shown, the magnetic sphere 10 has a magnetic pole in the direction of the main axis. The main axis coincides with the line connecting the N and S poles of the magnetic sphere and is a specific axis on the magnetic sphere. The magnetic sphere 10 according to the embodiment of the present application has an N pole and an S pole at both ends of a certain diameter. The magnetic field distribution of the magnetic sphere 10 is shown, for example, by a magnetic field distribution diagram.Figure 1

[0065] Figure 2 Fig. 1 shows a schematic diagram of a magnetic ball calibration device according to a first embodiment of the present application. As shown in Fig. 1, the magnetic ball calibration device according to the first embodiment of the present application comprises a tri-axial magnetic field sensor 20, a first driving unit 40 and a data processing unit 60. Figure 2

[0066] The first driving unit 40 is configured to drive the magnetic ball 10 to rotate in the first direction.

[0067] The tri-axial magnetic field sensor 20 is arranged adjacent to the magnetic ball 10 to obtain detection data of the tri-axial magnetic field components during the rotation of the magnetic ball 10.

[0068] The data processing unit 60 is connected to the tri-axial magnetic field sensor 20 to receive the detection data of the tri-axial magnetic field components, and obtain a zero point position P0 at which the magnetic field strength component in the selected direction is zero according to the detection data, and obtain a calibration position of the magnetic ball according to the detection data and the zero point position P0, and calibrate the magnetic ball according to the calibration position of the magnetic ball. The zero point position P0 includes not only the position information of the point, but also the data variation direction of the point, etc.

[0069] In the calibration position of the magnetic ball 10, the main shaft coincides with the direction of the second axis, the first axis is perpendicular to the second axis, the tri-axial magnetic field components include X-axis magnetic field component, Y-axis magnetic field component and Z-axis magnetic field component, the direction of the Z-axis magnetic field component coincides with the direction of the second axis, and the direction of the Y-axis magnetic field component coincides with the direction of the first axis.

[0070] Specifically, the magnetic ball 10 can rotate around the first axis 110 and / or the second axis 120 (i.e. in the first direction and / or the second direction), and during the movement of the magnetic ball 10, the first axis 110 keeps a fixed posture (e.g. a fixed angle) relative to the second axis 120. Alternatively, the rotation shaft of the first axis 110 and / or the second axis 120 is fixed in position, or the rotation shaft is fixedly installed in a capsule endoscope system. Preferably, the first axis 110 and the second axis 120 both pass through the center of the magnetic ball 10, and the first axis 110 is perpendicular to the second axis 120. Accordingly, a tri-axial (three-dimensional orthogonal coordinate system) is established. Alternatively, in the coordinate system, the straight line along which the first axis 110 lies is the Y-axis, and the center of the magnetic ball 10 is the origin. The tri-axial magnetic field components are the magnetic field components on the three axes of the three-dimensional orthogonal coordinate system.

[0071] ​​Optionally, the three-axis magnetic field components are determined by the orientation of the three-axis magnetic field sensor 20 itself, specifically, by the chip (not shown) of the sensor. The three-axis directions of the three-axis magnetic field components are as follows: the Z1 axis is perpendicular to the chip plane and points upwards, and the X1 and Y1 axes are parallel to the chip plane. The X1, Y1 and Z1 axes of the chip correspond to the X, Y and Z axes of the three-dimensional orthogonal coordinate system. Hereinafter, the three-axis directions of the three-axis magnetic field components are described in the three-axis directions of the three-dimensional orthogonal coordinate system, i.e., the three-axis magnetic field components include the X-axis magnetic field component, the Y-axis magnetic field component and the Z-axis magnetic field component; the direction of the Z-axis magnetic field component coincides with the direction of the second axis 120; and the direction of the Y-axis magnetic field component coincides with the direction of the first axis 110.

[0072] In the present embodiment, when calibration is performed, the first driving unit 40 drives the magnetic sphere 10 to rotate around the first axis 110 (in the first direction) by a first angle. Optionally, the first driving unit 40 drives the magnetic sphere 10 to rotate around the first axis 110. The magnetic sphere calibration device further includes the three-axis magnetic field sensor 20 placed adjacent to the magnetic sphere 10, for detecting the magnetic field strength of the magnetic sphere 10, especially the change in the magnetic field strength during rotation of the magnetic sphere 10.

[0073] More specifically, the three-axis magnetic field sensor 20 is located directly above the magnetic sphere 10 (i.e., along the Z axis, at the top end of the magnetic sphere 10), for detecting the magnetic field strength of the magnetic sphere 10 in the three-axis directions (i.e., the magnetic field strength in each direction in the three-dimensional space). In other embodiments of the present application, the three-axis magnetic field sensor 20 can also be arranged at other positions, as long as it can accurately obtain the magnetic field strength data of the magnetic sphere 10 during rotation.

[0074] In an embodiment, the first driving unit 40 can be located at the side of the magnetic sphere 10 (e.g., on both sides of the magnetic sphere 10), for driving the magnetic sphere 10 to rotate around the first axis 110.

[0075] The three-axis magnetic field sensor 20 is placed adjacent to the magnetic sphere 10 to detect the detection data of the three-axis magnetic field components of the magnetic sphere 10 during rotation (e.g., to detect the magnetic field strength of the magnetic sphere 10 in each direction in the three-dimensional space). In embodiments of the present application, the distance between the three-axis magnetic field sensor 20 and the surface of the magnetic sphere 10 can be adjusted according to the magnetic field strength of the magnetic sphere 10 and / or the sensitivity of the three-axis magnetic field sensor 20. The present application does not further limit the distance between the three-axis magnetic field sensor 20 and the outer surface of the magnetic sphere 10, as long as the three-axis magnetic field sensor 20 can accurately obtain the magnetic field strength data of the magnetic sphere 10. In addition, the first driving unit 40 in the present embodiment can directly control the rotation of the magnetic sphere 10, or can control the rotation of the magnetic sphere 10 through a transmission component (not shown), which will not be described here.

[0076] For the convenience of installation and the improvement of measurement accuracy, in an optional embodiment, the first shaft 110 or the second shaft 120 passes through the three-axis magnetic field sensor 20, and the position of the three-axis magnetic field sensor 20 can be used as the detection position.

[0077] The data processing unit 60 is connected with the three-axis magnetic field sensor 20 to receive the detection data of the three-axis magnetic field components, and to obtain the calibration position of the magnetic ball 10 according to the detection data obtained when the magnetic ball 10 rotates. The connection between the data processing unit 60 and the three-axis magnetic field sensor 20 can be wired or wireless.

[0078] In the embodiment, the data processing unit 60 includes a first processing unit (not shown) and a second processing unit (not shown). The first processing unit is used to obtain a zero point position P0 at which the magnetic field strength in the Z-axis direction is zero according to the detection data. It should be noted that the zero point position P0 obtained by the first processing unit is position information (or angle information). The second processing unit is used to determine the data direction of the zero point position P0 according to the detection data. The second processing unit is used to obtain the first calibration position V0 and the second calibration position H0 of the magnetic ball 10 according to the zero point position P0, the data direction of the zero point position P0, and the detection data.

[0079] In a preferred embodiment of the present application, the three-axis magnetic field sensor 20 and the first driving unit 40 are fixedly installed, which is convenient for the integrated design of the magnetic ball calibration device. In order to simplify the structure of the capsule endoscope system, in the embodiment of the present application, the first driving unit 40 can be a driving component for driving the magnetic ball 10 to rotate on the magnetic control device of the capsule endoscope system.

[0080] In an optional embodiment of the present application, in order to support the three-axis magnetic field sensor 20, a magnetic field plate 30 is arranged adjacent to the position of the magnetic ball 10, and the three-axis magnetic field sensor 20 is arranged on the magnetic field plate 30. The magnetic field plate 30 is used to mount the three-axis magnetic field sensor 20, and the overall structure of the magnetic field plate 30 is flat, occupies small space, and can fully cover the magnetic ball 10, so as to facilitate the flexible installation of the three-axis magnetic field sensor 20, and is conducive to reducing the volume of the overall device. In other embodiments of the present application, the magnetic field plate 30 can also be other structures for fixing the three-axis magnetic field sensor 20, which will not be described here.

[0081] In an optional embodiment of the invention, the magnetic ball calibration device further includes a readable storage medium for storing data. The readable storage medium is connected, for example, to the data processing unit 60 and the triaxial magnetic field sensor 20, respectively. Optionally, the readable storage medium is connected to the data processing unit 60 to store data processed by the data processing unit 60 and / or data to be received by the data processing unit 60 (e.g., detection data acquired by the triaxial magnetic field sensor 20 and / or motion data of the magnetic ball 10). Optionally, the readable storage medium is connected to the triaxial magnetic field sensor 20 to store the detection data acquired by the triaxial magnetic field sensor 20.

[0082] Figure 3 A flowchart of a magnetic ball calibration method according to a first embodiment of the present invention is shown.

[0083] Combination Figure 2 and Figure 3 As shown, the method for calibrating the magnetic ball 10 using the magnetic ball calibration device according to the first embodiment of the present invention includes the following steps:

[0084] In step S101, the magnetic ball 10 rotates by a first angle in a first direction to acquire detection data of the triaxial magnetic field components at the detection position during the rotation. The detection position is a predetermined detection location, such as the location of the detection device (triaxial magnetic field sensor). Preferably, the first angle is greater than 180°. In a preferred embodiment of this application, the first angle of rotation of the magnetic ball 10 is 200°, which ensures that the rotation position of the magnetic ball 10 necessarily includes the zero point position P0, and also prevents unnecessary computation caused by excessive data introduced by excessive rotation of the magnetic ball 10, thus improving the efficiency of magnetic ball calibration.

[0085] In step S102, the calibration position of the magnetic ball 10 is calculated based on the detection data.

[0086] When the magnetic ball 10 is in the calibration position, the magnetic polarization direction of the magnetic ball 10 coincides with the axial direction of the second axis 120, that is, the main axis of the magnetic ball 10 coincides with the second axis 120.

[0087] Combination Figure 2 As shown, the first driving unit 40 drives the magnetic ball 10 to rotate around the first axis 110 by a first angle. During the rotation of the magnetic ball 10 around the first axis 110, the triaxial magnetic field sensor 20 acquires the detection data of the triaxial magnetic field components at the detection position during the rotation. In this embodiment, the detection position, i.e., the position where the triaxial magnetic field sensor 20 is located, is used as an example for explanation.

[0088] Furthermore, the data processing unit 60 receives the detection data of the acquired triaxial magnetic field components and calculates the calibration position of the magnetic ball 10 based on the detection data of the triaxial magnetic field components.

[0089] It is worth mentioning that in this invention, the triaxial magnetic field sensor 20 can be arranged around the magnetic sphere 10 and can be positioned at any location capable of accurately detecting changes in the magnetic field of the magnetic sphere 10. When calculating the angle, compensation is made by increasing or decreasing one or more deflection angles. In the process of calculating the origin position of the magnetic sphere 10, the determination of the origin is still obtained by sensing and processing the changes in the magnetic field of the magnetic sphere 10 during its rotation. This deflection angle can be obtained through the positional relationship between the triaxial magnetic field sensor 20 and the rotation axis of the magnetic sphere 20.

[0090] It should be noted that the data processing unit 60 can obtain the calibration position of the magnetic ball 10 based on the change in the rotation angle of the magnetic ball 10 during its rotation, according to the detection data of the three-axis magnetic field components. When the motion mode of the magnetic ball 10 is clear, that is, when the rotation angle of the magnetic ball 10 satisfies a certain relationship with time, the data processing unit 60 can obtain the calibration position of the magnetic ball 10 based on the change in the detection data of the magnetic ball 10 during its rotation.

[0091] In step S103, the magnetic ball 10 is calibrated according to its calibration position.

[0092] Based on the calculated calibration position, rotate the magnetic ball 10 to the calibration position to complete the calibration.

[0093] Using the above-described magnetic ball calibration method, the magnetic ball 10, whose current position deviates from the calibration position, can be corrected (calibrated) by rotating the magnetic ball 10 to the calibration position. For example, the magnetic ball 10 can be calibrated so that its magnetic polarization direction coincides with the first axis 110, or the magnetic ball 10 can be calibrated so that its magnetic polarization direction is perpendicular to the first axis 110 (i.e., its magnetic polarization direction coincides with the second axis 120).

[0094] Figure 4 A flowchart of a magnetic ball calibration method according to a second embodiment of the present invention is shown. Figure 4 As shown, the magnetic ball calibration method according to the second embodiment of the present invention is a further improvement on the magnetic ball calibration method in the first embodiment.

[0095] like Figure 4 As shown in (a), the second embodiment of the present invention includes the following steps:

[0096] In step S201, the magnetic ball 10 is rotated about the first axis by a first angle.

[0097] The magnetic ball 10 rotates vertically, that is, the magnetic ball 10 rotates around the first axis 110 by a first angle, wherein the first angle is greater than 180°, for example, 200°, so that during the rotation of the magnetic ball 10, the zero point position can pass through the detection position of the triaxial magnetic sensor 20.

[0098] In step S202, the zero point position P0 where the magnetic field strength component of the magnetic ball is zero in the second axis direction is obtained based on the detection data;

[0099] The changes in magnetic field strength at the detection position were detected and recorded during the rotation of the magnetic ball 10 around the first axis. Several sets of detection data (b) of the three-axis magnetic field components at the detection position were recorded during the rotation. x0 b y0 b z0 ), (b x1 b y1 b z1 ), …, (b xn b yn b zn In this method, if the component of the magnetic field in the selected direction is zero in a set of detected data, the rotation position of the magnetic ball 10 corresponding to that set of data is the zero-point position P0. Alternatively, the zero-point position P0 is the rotation position of the magnetic ball 10 when the triaxial magnetic field sensor 20 at the detection position detects that the component of the magnetic field strength in the selected direction is zero. In this embodiment, the determination is based on whether the component of the magnetic field strength in the Z-axis direction is zero. The zero-point position P0 reflects the angle through which the magnetic ball 10 rotates from the start of its rotation to the position where the magnetic field strength in the selected direction is zero. In other embodiments, the selected direction can also be either the X-axis direction or the Y-axis direction, depending on the actual situation.

[0100] However, in actual operation, due to the limited measurement accuracy of the triaxial magnetic field sensor 20, when the measurable value is 0, the magnetic induction intensity of the magnetic ball 10 in the selected direction is not 0, that is, the zero point position P0 may not be accurately obtained by detection.

[0101] Accordingly, in an optional embodiment of the present invention, finding the zero point position P0 includes:

[0102] The near-zero position P1 of the magnetic field in the selected direction is detected. Here, the near-zero position P1 is the position where the magnetic field component of the magnetic sphere 10 in that direction is close to zero. Furthermore, the measurement value of the triaxial magnetic field sensor 20 at the near-zero position P1 and the measurement value at the next position after P1 show positive and negative variations.

[0103] The zero position P0 is obtained from the near-zero position P1. Optionally, in this embodiment, the near-zero position P1 can be selected as the zero position P0.

[0104] Preferably, the zero position P0 can also be calculated based on the near zero position P1, for example, by using the difference method to calculate the zero position P0, which will not be elaborated here.

[0105] In step S203, the data direction of the zero point position P0 is determined.

[0106] Specifically, as the magnetic ball 10 rotates, determining the direction of the zero-point position P0 is equivalent to determining whether the change in the magnetic field strength component in the Z-axis direction detected when the zero-point position P0 is detected is from positive to negative or from negative to positive.

[0107] In step S204, the calibration position of the magnetic ball is calculated based on the direction of the zero position P0 and the detection data.

[0108] In this embodiment, the calibration positions include a first calibration position V0 and a second calibration position H0. The first calibration position V0 determines the calibration position in a first direction (i.e., the direction in which the magnetic ball 10 rotates about the first axis 110); the second calibration position H0 determines the calibration position in a second direction (i.e., the direction in which the magnetic ball 10 rotates about the second axis 120).

[0109] like Figure 4 As shown in (b) of the figure, in an optional embodiment of the present invention, the magnetic ball is controlled to rotate by a first angle greater than 180° in a first direction, and then the three-dimensional magnetic field data (b) acquired by the triaxial magnetic field sensor during the rotation of the magnetic ball are recorded. x0 b y0 b z0 ), (b x1 b y1 b z1 ), …, (b xn b yn b zn The position of the zero point is detected by the data in the z-direction of the magnetic field, i.e., the zero point position P0.

[0110] The angle of rotation when the magnetic ball reaches the zero point is α. The angle range of α is, for example, a left-closed and right-open interval from 0 to 2π.

[0111] The x-direction component b at the zero point P0 xi and the y-direction component b yi The included angle between them is β, β = atan2(b yi ,b xi According to the x-direction component b) xi and the y-direction component b yi The numerical value of β can include the following cases:

[0112] When b xi When >0, β=arctan(b yi / b xi );

[0113] When b yi ≥0, b xi When < 0, β = arctan(b) yi / b xi )+π;

[0114] When b yi ≤0, b xi When < 0, β = arctan(b) yi / b xi -π;

[0115] When b yi ≥0, b xi When β = 0, β = π / 2;

[0116] When b yi ≤0, b xi When β = 0, β = -π / 2.

[0117] The angular range of β is, for example, the left-open and right-closed interval from -π to π.

[0118] If the direction of change of the magnetic field strength at the zero point P0 is from positive to negative, then the first calibration position of the magnetic ball 10 (i.e., the origin of the magnetic ball 10 rotating around the first axis 110) is V0 = α - 90°. At this time, the second calibration position of the magnetic ball 10 (i.e., the origin of the magnetic ball 10 rotating around the second axis 120) is H0 = -β.

[0119] If the direction of change of the magnetic field strength at the zero point P0 is from negative to positive, then the first calibration position of the magnetic sphere 10 is V0 = α + 90°. At this time, the second calibration position of the magnetic sphere 10 is H0 = 180° - β.

[0120] The first processing unit is used to obtain the zero-point position where the magnetic field strength in the Z-axis direction is zero at a specific location based on the detection data. The second processing unit includes a data direction determination function for the zero-point position P0 based on the detection data. Furthermore, the second processing unit is also used to obtain the first calibration position V0 and the second calibration position H0 of the magnetic sphere 10 based on the zero-point position P0, the data direction of the zero-point position P0, and the detection data.

[0121] Figure 5 A schematic diagram of the magnetic ball after calibration according to an embodiment of the present invention is shown. Figure 5 As shown, after the magnetic ball 10 is calibrated according to an embodiment of the present invention, the main axis of the magnetic ball (i.e., the straight line where the N magnetic pole and the S magnetic pole are located) coincides with the second axis 120.

[0122] In this embodiment, the zero point P0 of the magnetic ball 10 is used as the calibration standard. The data at this position has good discrimination, which effectively avoids the problem of insufficient magnetic ball calibration accuracy, reduces the impact of actual measurement errors on the calibration results, and makes the calibration accuracy higher.

[0123] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0124] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A magnetic sphere calibration method, characterized by, The method comprises the following steps: rotating the magnetic sphere around the first axis by a first angle to obtain detection data of three-axis magnetic field components at a detection position during rotation, the first angle being greater than or equal to 180°; obtaining a zero point position P0 at which the magnetic field strength component of the magnetic sphere in the direction of the second axis is zero according to the detection data; obtaining a calibration position of the magnetic sphere according to the detection data and the zero point position P0; calibrating the magnetic sphere according to the calibration position of the magnetic sphere; wherein when the magnetic sphere is at the calibration position, the magnetic polarization direction of the magnetic sphere coincides with the second axis; the first axis and the second axis are perpendicular to each other; the three-axis magnetic field components include an X-axis magnetic field component, a Y-axis magnetic field component and a Z-axis magnetic field component; the direction of the Z-axis magnetic field component coincides with the direction of the second axis, and the Y-axis magnetic field component coincides with the direction of the first axis.

2. The magnetic sphere calibration method of claim 1, wherein, The step of obtaining a zero point position P0 at which the magnetic field strength component of the magnetic sphere in the direction of the second axis is zero according to the detection data comprises: obtaining a plurality of groups of detection data of changes in magnetic field strength at a detection position during rotation of the magnetic sphere around the first axis; obtaining a magnetic field strength component in the direction of the second axis for each group of detection data according to the detection data; judging whether the magnetic field strength component in the direction of the second axis is 0 to obtain a zero point position P0 at which the magnetic field strength component in the direction of the second axis is 0.

3. The magnetic sphere calibration method of claim 1, wherein, The step of obtaining a zero point position P0 at which the magnetic field strength component of the magnetic sphere in the direction of the second axis is zero according to the detection data comprises: obtaining a near-zero point position P1 at which the magnetic field component in the direction of the second axis is close to zero according to the detection data; taking the near-zero point position P1 as the zero point position P0.

4. The magnetic sphere calibration method of claim 2 or 3, wherein, The step of obtaining a calibration position of the magnetic sphere according to the detection data and the zero point position P0 comprises: judging the data direction of the zero point position P0 during rotation of the magnetic sphere around the first axis by the first angle; obtaining a first calibration position V0 and a second calibration position H0 of the magnetic sphere according to the data direction of the zero point position P0, the zero point position P0 and the detection data.

5. The magnetic sphere calibration method of claim 4, wherein, The step of obtaining a calibration position of the magnetic sphere according to the detection data and the zero point position P0 further comprises: when the data direction of the zero point position P0 changes from positive to negative, the first calibration position V0 = α-90° and the second calibration position H0 = -β; when the data direction of the zero point position P0 changes from negative to positive, the first calibration position V0 = α+90° and the second calibration position H0 = 180°-β, Wherein, the three-axis magnetic field components at the zero point position P0 are (b xi , b yi , b zi ) ; α is the angle of rotation of the magnetic sphere when reaching the zero point position P0; β is the angle between the x-direction component b xi and the y-direction component b yi of the zero point position P0.

6. A magnetic sphere calibration device, the magnetic sphere having magnetic poles in a direction of a principal axis, characterized by comprises: a first driving unit for driving the magnetic sphere to rotate around the first axis by a first angle; the first angle is greater than or equal to 180°; a three-axis magnetic field sensor arranged adjacent to the magnetic sphere to obtain detection data of three-axis magnetic field components at a detection position during rotation of the magnetic sphere; and The data processing unit is connected with the three-axis magnetic field sensor to receive detection data of the three-axis magnetic field components, to obtain a zero point position P0 at which the magnetic field intensity in the second axis direction is zero according to the detection data, and to obtain a calibration position of the magnetic ball according to the detection data and the zero point position P0, and to calibrate the magnetic ball according to the calibration position of the magnetic ball. When the magnetic ball is located at the calibration position, the main axis coincides with the second axis. The first axis and the second axis are perpendicular to each other. The three-axis magnetic field components include an X-axis magnetic field component, a Y-axis magnetic field component and a Z-axis magnetic field component. The direction of the Z-axis magnetic field component coincides with the direction of the second axis, and the Y-axis magnetic field component coincides with the direction of the first axis.

7. The magnetic sphere calibration device of claim 6, wherein, The first angle is 200°.

8. The magnetic sphere calibration device of claim 6, wherein, The data processing unit includes: The first processing unit is configured to: According to the detection data, obtain the magnetic field intensity component in the second axis direction of each group of detection data, and determine whether the magnetic field intensity component in the second axis direction is 0 to obtain a zero point position P0 at which the magnetic field intensity component in the second axis direction is zero.

9. The magnetic sphere calibration device of claim 6, wherein, The data processing unit includes: The first processing unit is configured to: According to the detection data, obtain a position at which the magnetic field component in the second axis direction is close to zero as a near-zero point position P1. The near-zero point position P1 is used as the zero point position P0.

10. The magnetic sphere calibration device of claim 8 or 9, wherein, The data processing unit includes a second processing unit configured to: According to the detection data, determine the data direction of the zero point position P0.

11. The magnetic sphere calibration device of claim 6, wherein, According to the zero point position P0, the data direction of the zero point position P0 and the detection data, obtain a first calibration position V0 and a second calibration position H0 of the magnetic ball. The first axis or the second axis passes through the three-axis magnetic field sensor, and the detection position includes a position at which the three-axis magnetic field sensor is located.

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