Magnetic ball calibration method and magnetic ball calibration device

Abstract

The present application discloses a method and device for calibrating a magnetic ball. The magnetic ball calibration method according to the present application includes the steps of rotating a magnetic ball (10) by a first angle around a first axis (110) and acquiring detection data during the rotation, and detecting a zero point position P where the component of the magnetic field strength in the direction of a second axis (120) of the magnetic ball (10) becomes zero based on the detection data. 0 and a step of acquiring the detection data and the zero point position P 0 and calibrating the magnetic ball based on the calibration position of the magnetic ball. Here, when the magnetic ball (10) is located at the calibration position, the magnetization direction of the magnetic ball (10) overlaps with the second axis (120), the first axis (110) and the second axis (120) are perpendicular to each other, and 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 overlaps with the direction of the second axis (120), and the Y-axis magnetic field component overlaps with the direction of the first axis (110). According to the magnetic ball calibration method and the magnetic ball calibration device of the present application, the magnetic ball can be calibrated conveniently, quickly, and accurately.

Description

[Technical Field]

[0001] This application claims priority to a Chinese patent application filed on January 28, 2022, bearing application number 202210104801.7 and entitled "Method for Calibrating Magnetic Ball and Apparatus for Calibrating Magnetic Ball," and incorporates the contents of the aforementioned Chinese patent application by reference to the entire specification, claims, drawings and abstract thereof.

[0002] The present application relates to the technical fields of magnetic control and capsule endoscopy, and in particular to a method and apparatus for calibrating a magnetic ball. [Background technology]

[0003] Capsule endoscopy, under the active control of an external magnetic control device, can perform detailed and comprehensive examinations. Compared with intubation endoscopy, capsule endoscopy has the advantages of greater comfort and a lower risk of cross-infection, and its popularity in clinical applications is steadily increasing.

[0004] In a magnetically controlled capsule endoscope system, the permanent magnet (usually a magnetic sphere, or magnetic ball) in the external magnetic control device is the core component that controls the movement of the capsule endoscope. The magnetic field is changed by controlling the orientation and / or position of the magnetic ball. The capsule endoscope can then perform corresponding movements, such as translation, rotation, and inversion, depending on the magnetic field being changed. The magnetic ball then influences the orientation of the capsule endoscope through the direction of the magnetic field. In actual use, uncertainty in the magnetic field direction of the permanent magnet or variations in the magnetic pole position can lead to large errors in the orientation angle of the capsule endoscope, affecting the accuracy of the capsule endoscope's orientation and ultimately the accuracy of the information collected by the capsule endoscope. The orientation of the magnetic ball within the external magnetic control device of the capsule endoscope must be calibrated during use.

[0005] In the prior art, multiple sensors are usually used to acquire magnetic field data and determine the magnetic field direction of the magnetic ball, which can accurately determine the direction of the magnetic ball, but the process is complicated and the operation is complex, which is disadvantageous for widespread application.

[0006] Therefore, there is a need for a simpler, more convenient, and more accurate method and apparatus for calibrating a magnetic ball. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above-mentioned problems, an object of the present application is to provide a method and apparatus for calibrating a magnetic ball, which can calibrate the magnetic ball accurately, conveniently and quickly. [Means for solving the problem]

[0008] A method for calibrating a magnetic ball according to one aspect of the present application includes: A step of rotating the magnetic ball around a first axis by a first angle of 180° or more and acquiring detection data of three-axis magnetic field components at a detection position during the rotation; A step of acquiring a zero point position P0 where the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero based on the detection data; obtaining a calibration position of the magnetic ball based on the detection data and the zero point position P0; calibrating the magnetic ball based on the calibration position of the magnetic ball; wherein when the magnetic ball is positioned at the calibration position, the magnetization direction of the magnetic ball overlaps 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 overlaps with the direction of the second axis, and the Y-axis magnetic field component overlaps with the direction of the first axis.

[0009] Preferably, to obtain the zero point position P0 where the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero based on the detection data, obtaining multiple sets of detection data relating to changes in magnetic field strength at detection positions during rotation of the magnetic ball about the first axis; Obtaining a component of magnetic field strength in a second axis direction for each set of detection data based on the detection data; and The method includes determining whether the component of the magnetic field strength in the second axis direction is zero, and obtaining a zero point position P0 where the component of the magnetic field strength in the second axis direction is zero.

[0010] Preferably, to obtain the zero point position P0 where the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero based on the detection data, This includes acquiring a position close to the zero point of the magnetic field component in the second axis direction as a zero point approach position P1 based on the detection data, and setting the zero point approach position P1 as the zero point position P0.

[0011] Preferably, the step of obtaining the calibration position of the magnetic ball based on the detection data and the zero point position P0 includes: Determining direction data of the zero point position P0 during the magnetic ball rotating around a first axis by a first angle; and The method includes obtaining a first calibration position V0 and a second calibration position H0 of the magnetic ball based on the direction data of the zero point position P0, the zero point position P0 and the detection data.

[0012] Preferably, when calculating the calibration position of the magnetic ball based on the detection data and the zero point position P0, When the direction data of the zero point position P0 changes from positive to negative, the first calibration position is set to V0=α-90°, and the second calibration position is set to H0=-β; When the direction data of the zero point position P0 changes from negative to positive, the first calibration position is set to V0=α+90°, and the second calibration position is set to H0=180°-β; Here, the triaxial magnetic field components at the zero point position P0 are (b xi ,byi ,b zi ) and α is the angle of rotation when the magnetic ball reaches the zero point position P0, β is the x-direction component b at the zero point position P0 xi and the y-direction component b yi is the angle between

[0013] According to another aspect of the present application, there is provided a calibration device for a magnetic ball, the magnetic ball having magnetic poles along a major axis direction, the calibration device for the magnetic ball comprising: a first drive unit that drives the magnetic ball to rotate by a first angle around a first axis; a three-axis magnetic field sensor disposed adjacent to the magnetic ball for acquiring detection data of three-axis magnetic field components at a detection position during rotation of the magnetic ball; a data processing unit connected to the three-axis magnetic field sensor to receive detection data of the three-axis magnetic field components, obtain a zero point position P0 where the magnetic field strength in the second axis direction at the detection position is zero based on the detection data, obtain a calibration position of the magnetic ball based on the detection data and the zero point position P0, and calibrate the magnetic ball based on the calibration position of the magnetic ball; wherein when the magnetic ball is positioned at the calibration position, the primary axis overlaps with the secondary 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 overlaps with the direction of the second axis, and the Y-axis magnetic field component overlaps with the direction of the first axis.

[0014] Preferably, the first angle is greater than or equal to 180°, or 200°.

[0015] Preferably, the data processing unit includes a first processing unit; The first processing unit obtains the magnetic field strength component in the second axis direction of each set of detection data based on the detection data, and determines whether the magnetic field strength component in the second axis direction is 0, and obtains the zero point position P0 where the magnetic field strength component in the second axis direction is 0.

[0016] Preferably, the data processing unit includes a first processing unit; The first processing unit acquires a position close to the zero point of the magnetic field component in the second axis direction as a zero point approach position P1 based on the detection data, and sets the zero point approach position P1 as a zero point position P0.

[0017] Preferably, the data processing unit includes a second processing unit; The second processing unit determines the direction data of the zero point position P0 based on the detection data, and obtains the first calibration position V0 and the second calibration position H0 of the magnetic ball based on the zero point position P0, the direction data of the zero point position P0 and the detection data.

[0018] Preferably, the first axis or the second axis passes through the three-axis magnetic field sensor; The detection position includes a position where the three-axis magnetic field sensor is located.

[0019] According to the magnetic ball calibration device and magnetic ball calibration method of the present embodiment, a single three-axis magnetic field sensor is used to determine the direction of the magnetic ball, which is simple to operate and can calibrate the magnetic ball conveniently, quickly and accurately, providing an accurate basis for determining the posture of the capsule endoscope.

[0020] According to the magnetic ball calibration device and magnetic ball calibration method of the present invention, the magnetic ball is calibrated by detecting and analyzing the magnetic field value at the detection position, and the operation is simple and convenient.

[0021] According to the magnetic ball calibration device and magnetic ball calibration method of the present embodiment, automatic calibration can be achieved by rotating the magnetic ball at a certain angle, which makes it easy to control the calibration process and avoids the introduction of errors due to human operation.

[0022] According to the magnetic ball calibration device and magnetic ball calibration method of the present application, the calibration position of the magnetic ball is determined based on the zero point position and the magnetic field value, thereby avoiding detection errors caused by data division that is too small and improving the calibration accuracy of the magnetic ball. [Brief explanation of the drawings]

[0023] The above and other objects, features, and advantages of the present application will become more apparent from the following description of the embodiments of the present application with reference to the drawings, in which: [Figure 1] 3 is a schematic diagram of the magnetic field distribution of a magnetic ball according to an embodiment of the present application. [Figure 2] 1 is a perspective view of a magnetic ball calibration device according to a first embodiment of the present invention; [Figure 3] FIG. 2 is a flowchart illustrating a method for calibrating a magnetic ball according to a first embodiment of the present invention. [Figure 4] FIG. 10 is a flowchart of a method for calibrating a magnetic ball according to a second embodiment of the present application. [Figure 5] FIG. 10 is a flowchart illustrating a process for obtaining a first calibration position and a second calibration position according to an embodiment of the present invention. [Figure 6] 1 is a schematic diagram of a magnetic ball according to an embodiment of the present application after calibration; DETAILED DESCRIPTION OF THE INVENTION

[0024] Various embodiments of the present application will now be described in more detail with reference to the accompanying drawings. In each drawing, identical elements are represented by the same or similar reference numerals. For clarity, parts of the drawings are not drawn to scale. Also, some known parts may not be shown in the drawings.

[0025] The specific embodiments of the present application will be further described below in conjunction with the accompanying drawings and examples. In order to make the present application more clearly understandable, many specific details of the present application will be described below, such as the structure, materials, dimensions, processing processes and techniques of parts. However, as can be understood by those skilled in the art, the present application may not necessarily be realized according to these specific details.

[0026] When describing the structure of a part, when a layer or region is referred to as being "on top of" or "above" another layer or region, it should be understood that this may be directly on top of the other layer or region, or that there may be additional layers or regions between the other layer or region. Also, when the part is inverted, the layer or region in question would be "under" or "beneath" the other layer or region.

[0027] FIG. 1 shows a schematic diagram of the magnetic field distribution of a magnetic ball 10 according to an embodiment of the present invention. As shown in FIG. 1, the magnetic ball 10 according to the embodiment of the present invention has magnetic poles (magnetic fields in a specific direction) along the main axis. The main axis overlaps with the connecting line between the north and south magnetic poles of the magnetic ball, and is a specific axis of the magnetic ball. According to the magnetic ball 10 according to the embodiment of the present invention, both ends of a certain diameter are the north and south magnetic poles, respectively. The magnetic field distribution of the magnetic ball 10 is shown, for example, by the magnetic lines in FIG. 1.

[0028] FIG. 2 shows a perspective view of a magnetic ball calibration device according to a first embodiment of the present application. As shown in FIG. 2, in one aspect, the embodiment of the present application provides a magnetic ball calibration device including a three-axis magnetic field sensor 20, a first driving unit 40, and a data processing unit 60. The magnetic ball 10 includes a first direction and a second direction. Here, the first direction is the direction in which the magnetic ball 10 rotates around a first axis 110. The second direction is the direction in which the magnetic ball 10 rotates around the second axis.

[0029] The first driving unit 40 drives the magnetic ball 10 to rotate in a first direction.

[0030] The three-axis magnetic field sensor 20 is disposed adjacent to the magnetic ball 10 to obtain detection data of the three-axis magnetic field components during rotation.

[0031] The data processing unit 60 is connected to the three-axis magnetic field sensor 20 to receive the detection data of the three-axis magnetic field components, and obtains a zero point position P0 from the detection data where the magnetic field intensity component in the selected direction at the detection position is zero, and obtains a calibration position of the magnetic ball based on the detection data and the zero point position P0, and calibrates the magnetic ball based on the calibration position of the magnetic ball, where the zero point position P0 includes not only the position information of the point but also the data change direction of the point.

[0032] Here, as shown in Figure 6, when the magnetic ball 10 is in the calibration position, the primary axis overlaps with the secondary axis direction, and the primary axis and secondary 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 overlaps with the direction of the secondary axis. The direction of the Y-axis magnetic field component overlaps with the direction of the first axis.

[0033] Specifically, the magnetic ball 10 can rotate (i.e., rotate in a first direction and / or a second direction) around the first axis 110 and / or the second axis 120. During the movement of the magnetic ball 10, the first axis 110 maintains a fixed attitude (e.g., a fixed angle) relative to the second axis 120. Optionally, the positions of the rotation axes of the first axis 110 and / or the second axis 120 are fixed, or the rotation axes are fixedly attached within the capsule endoscope system. Preferably, both the first axis 110 and the second axis 120 pass through the spherical center of the magnetic ball 10, and the first axis 110 is perpendicular to the second axis 120. Based on this, a three-axis (three-dimensional Cartesian coordinate system) is constructed. Optionally, in this coordinate system, the line on which the first axis 110 is located is the Y-axis, and the spherical center of the magnetic ball 10 is the zero point. The three-axis magnetic field components are magnetic field components along the three axes of the three-dimensional Cartesian coordinate system.

[0034] Optionally, the three-axis magnetic field components are determined by the orientation of the three-axis magnetic field sensor 20 itself. Specifically, they are determined by the sensor chip (not shown). Regarding the three axial directions of the three-axis magnetic field components, the Z1 axis is perpendicular to the plane of the chip, and the X1 and Y1 axes are parallel to the plane of the chip. Here, the directions of the X1, Y1, and Z1 axes of the chip correspond to the directions of the X, Y, and Z axes in a three-dimensional Cartesian coordinate system. The three axes of the three-axis magnetic field components described below will all be explained using the three axes of the three-dimensional Cartesian coordinate system. That is, 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 overlaps with the direction of the second axis 120. The direction of the Y-axis magnetic field component overlaps with the direction of the first axis 110.

[0035] In this embodiment, when performing calibration, the first driving unit 40 drives the magnetic ball 10 to rotate by a first angle about the first axis 110 (in a first direction). Optionally, the first driving unit 40 drives the magnetic ball 10 to rotate about the first axis 110. The magnetic ball calibration device also includes a three-axis magnetic field sensor 20 disposed adjacent to the magnetic ball 10. The three-axis magnetic field sensor 20 is used to detect the magnetic field strength of the magnetic ball 10, particularly changes in the magnetic field strength during rotation of the magnetic ball 10.

[0036] More specifically, the three-axis magnetic field sensor 20 is positioned directly above the magnetic ball 10 (i.e., positioned at the tip of the magnetic ball 10 along the Z axis) and is used to detect the magnetic field strength in the three-axis directions of the magnetic ball 10 (i.e., the magnetic field strength in each direction in three-dimensional space). Meanwhile, in other embodiments of the present application, the three-axis magnetic field sensor 20 may be installed at other positions as long as it can accurately obtain data on the magnetic field strength while the magnetic ball 10 is rotating.

[0037] In one embodiment, the first driving unit 40 is located on the side of the magnetic ball 10 (for example, on both sides of the magnetic ball 10 ) and drives the magnetic ball 10 to rotate around the first axis 110 .

[0038] The three-axis magnetic field sensor 20 is disposed adjacent to the magnetic ball 10 and detects detection data of three-axis magnetic field components during rotation of the magnetic ball 10 (e.g., detects the magnetic field strength of the magnetic ball 10 in each direction in three-dimensional space). In the present embodiment, the distance between the three-axis magnetic field sensor 20 and the surface of the magnetic ball 10 is adjusted according to the magnetic field strength of the magnetic ball 10 and / or the sensitivity of the three-axis magnetic field sensor 20. In the present embodiment, the distance of the three-axis magnetic field sensor 20 from the outer surface of the magnetic ball 10 is not further limited as long as the three-axis magnetic field sensor 20 can acquire magnetic field strength data of the magnetic ball 10. Note that the first driving unit 40 in this embodiment may directly control the rotation of the magnetic ball 10 or may control the rotation of the magnetic ball 10 via a transmission member (not shown), but this will not be described further here.

[0039] In consideration of ease of installation and improvement of measurement accuracy, in one selectable embodiment, the first axis 110 or the second axis 120 passes through the three-axis magnetic field sensor 20. In this case, the position where the three-axis magnetic field sensor 20 is located can be set as the detection position.

[0040] The data processing unit 60 is connected to the three-axis magnetic field sensor 20 to receive the detection data of the three-axis magnetic field components, and rotates along with the magnetic ball 10 based on the detection data to obtain the calibrated position of the magnetic ball 10. Here, the connection between the data processing unit 60 and the three-axis magnetic field sensor 20 may be a wired connection or a wireless connection.

[0041] In this embodiment, the data processing unit 60 includes a first processing unit (not shown) and a second processing unit (not shown). The first processing unit obtains a zero point position P0, where the magnetic field strength in the Z-axis direction at a specific position is zero, based on the detection data. 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 directional data of the zero point position P0 based on the detection data. The second processing unit obtains a first calibration position V0 and a second calibration position H0 of the magnetic ball 10 based on the zero point position P0, the directional data of the zero point position P0, and the detection data.

[0042] In a preferred embodiment of the present application, the mounting positions of the three-axis magnetic field sensor 20 and the first driving unit 40 are relatively fixed, which facilitates the integrated design of the magnetic ball calibration device. To simplify the configuration of the capsule endoscope system, in this embodiment, the first driving unit 40 may be a driving assembly for driving and rotating the magnetic ball 10 in the magnetic control device of the capsule endoscope system.

[0043] In an alternative embodiment of the present application, a magnetic field plate 30, for example, is provided adjacent to the magnetic ball 10 to support the three-axis magnetic field sensor 20. The three-axis magnetic field sensor 20 is provided on the magnetic field plate 30. The magnetic field plate 30 is used to mount the three-axis magnetic field sensor 20. Moreover, the magnetic field plate 30 has a flat overall structure, occupies a small space, and can completely cover the magnetic ball 10, which is convenient for flexible mounting of the three-axis magnetic field sensor 20 and advantageous for reducing the volume of the entire device. In other embodiments of the present application, the magnetic field plate 30 may have other structures for fixing the three-axis magnetic field sensor 20. This will not be described further here.

[0044] In an alternative embodiment of the present application, the magnetic ball calibration device further includes a readable storage medium (not shown) for storing data. The readable storage medium is, for example, connected to the data processing unit 60 and the three-axis magnetic field sensor 20, respectively. Alternatively, the readable storage medium is connected to the data processing unit 60 for storing data calculated by the data processing unit 60 and / or data received by the data processing unit 60 (e.g., detection data acquired by the three-axis magnetic field sensor 20 and / or movement data of the magnetic ball 10). Alternatively, the readable storage medium is connected to the three-axis magnetic field sensor 20 for storing detection data acquired by the three-axis magnetic field sensor 20.

[0045] FIG. 3 shows a flowchart of a method for calibrating a magnetic ball according to a first embodiment of the present application.

[0046] As shown in FIGS. 2 and 3, the method for calibrating the magnetic ball 10 using the magnetic ball calibration device according to the first embodiment of the present application includes the following steps.

[0047] In step S101, the magnetic ball 10 is rotated in a first direction by a first angle to obtain detection data of the three-axis magnetic field components at a detection position during rotation. Here, the detection position is a preset detection position, such as the position where a detection device (three-axis magnetic field sensor) is located. Preferably, the first angle is greater than 180°. In a preferred embodiment of the present application, the first angle at which the magnetic ball 10 rotates is 200°. This ensures that the position to which the magnetic ball 10 rotates always includes the zero point position P0, prevents unnecessary calculations due to a large amount of data introduced by excessive rotation of the magnetic ball 10, and improves the efficiency of magnetic ball calibration.

[0048] In step S102, the calibrated position of the magnetic ball 10 is calculated from the detection data.

[0049] Here, when the magnetic ball 10 is in the calibration position, the magnetization direction of the magnetic ball 10 overlaps with the axial direction of the second axis 120 , that is, the main axis of the magnetic ball 10 overlaps with the second axis 120 .

[0050] 2, the first driving unit 40 drives the magnetic ball 10 to rotate by a first angle around the first axis 110. While the magnetic ball 10 rotates around the first axis 110, the three-axis magnetic field sensor 20 acquires detection data of the three-axis magnetic field components at the detection position during the rotation. In this embodiment, the detection position is described using the position where the three-axis magnetic field sensor 20 is located as an example.

[0051] Furthermore, the data processing unit 60 receives the acquired detection data of the three-axis magnetic field components, and calculates the calibrated position of the magnetic ball 10 based on the detection data of the three-axis magnetic field components.

[0052] In the present application, the three-axis magnetic field sensor 20 may be installed around the magnetic ball 10, and may be installed at any position where it can accurately detect changes in the magnetic field of the magnetic ball 10. When calculating the angle, the changes are compensated for by increasing or decreasing one or more deflection angles. In the process of measuring the zero point position of the magnetic ball 10 described above, the process of determining the zero point is still processed by inducing changes in the magnetic field during the rotation of the magnetic ball 10. Here, the deflection angle can be obtained by the positional relationship between the three-axis magnetic field sensor 20 and the rotation axis of the magnetic ball 10.

[0053] Furthermore, the data processing unit 60 can obtain the calibrated position of the magnetic ball 10 based on the change in the detected data of the three-axis magnetic field components with the rotation angle of the magnetic ball 10 during rotation of the magnetic ball 10. If the motion manner of the magnetic ball 10 is clear, that is, the rotation angle of the magnetic ball 10 and time satisfy a certain relationship, the data processing unit 60 can obtain the calibrated position of the magnetic ball 10 based on the change in the detected data over time during rotation of the magnetic ball 10.

[0054] In step S103, the magnetic ball 10 is calibrated based on the calibration position of the magnetic ball 10. Based on the calculated calibration position, the magnetic ball 10 is rotated to the calibration position, and the calibration is completed.

[0055] By using the above-described magnetic ball calibration method, the magnetic ball 10, which has a deviation between its current position and the calibration position, is corrected (calibrated), i.e., the magnetic ball 10 is rotated to the calibration position. For example, the magnetic ball 10 is corrected so that its magnetization direction coincides with the first axis 110, or so that its magnetization direction is perpendicular to the first axis 110 (i.e., so that its magnetization direction coincides with the second axis 120).

[0056] 4 shows a flowchart of the magnetic ball calibration method according to the second embodiment of the present invention. As shown in FIG. 4, the magnetic ball calibration method according to the second embodiment of the present invention is a further improvement over the magnetic ball calibration method in the first embodiment.

[0057] As shown in FIG. 4, the second embodiment of the present application includes the following steps:

[0058] In step S201, the magnetic ball 10 is rotated around the first axis by a first angle.

[0059] The magnetic ball 10 rotates vertically, i.e., the magnetic ball 10 rotates around the first axis 110 by a first angle, where the first angle is greater than 180°, e.g., 200°, thereby ensuring that the zero point position can pass through the detection position where the three-axis magnetic field sensor 20 is installed during the rotation of the magnetic ball 10.

[0060] In step S202, the zero point position P0 is found. From the detection data, a zero point position P0 where the component of the magnetic field strength of the magnetic ball 10 in the direction of the second axis 120 is zero is obtained.

[0061] The magnetic field intensity change at the detection position during the rotation of the magnetic ball 10 around the first axis 110 is detected and recorded, and several sets of detection data (b x0 ,b y0 ,b z0 ), (b x1 ,b y1 ,b z1 ), ... (b xn ,b yn ,b zn) is recorded. Here, if the component value of the magnetic field in the selected direction of one set of detected detection data is 0, the rotation position of the magnetic ball 10 corresponding to that set of data is the zero-point position P0. In other words, the zero-point position P0 is the rotation position of the magnetic ball 10 when the component of the magnetic field strength in the selected direction detected by the three-axis magnetic field sensor 20 at the detection position is zero. In this embodiment, this is determined based on whether the component of the magnetic field strength in the Z-axis direction is zero. The zero-point position P0 can reflect the angle of rotation of the magnetic ball 10 from when it starts to rotate to the position where the magnetic field strength in the selected direction becomes zero. In other embodiments, the above-mentioned selected direction can be selected as either the X-axis direction or the Y-axis direction depending on the actual situation.

[0062] However, in actual operation, due to the limited measurement accuracy of the three-axis magnetic field sensor 20, when the measurable value is 0, the magnetic induction strength 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.

[0063] Therefore, in an alternative embodiment of the present application, finding the zero point position P0 specifically includes:

[0064] The zero-point approach position P1 of the magnetic field in the selected direction is detected and acquired. Here, the zero-point approach position P1 refers to the position where the magnetic field component of the magnetic ball 10 in this direction is close to the zero point. In addition, there is a positive / negative change between the measurement value at the zero-point approach position P1 of the three-axis magnetic field sensor 20 and the measurement value at the position next to the zero-point approach position P1.

[0065] The zero point position P0 is obtained based on the zero point approach position P1. Optionally, in this embodiment, the zero point approach position P1 can be selected as the zero point position P0.

[0066] Preferably, the zero point position P0 can also be calculated based on the zero point approach position P1. For example, the zero point position P0 can be calculated using a difference method. No further description will be given here.

[0067] In step S203, the direction of the zero point position P0 is determined.

[0068] Specifically, determining the direction of the zero point position P0 as the magnetic ball 10 rotates means determining whether the change in the component of the magnetic field strength in the detected Z-axis direction changes from positive to negative or from negative to positive when the zero point position P0 is detected.

[0069] In step S204, the calibration position of the magnetic ball is calculated based on the direction of the zero point position P0 and the detection data.

[0070] In this embodiment, the calibration positions include a first calibration position V0 and a second calibration position H0, where the first calibration position V0 determines the calibration position in a first direction (i.e., the direction in which the magnetic ball 10 rotates around the first axis 110), and the second calibration position H0 determines the calibration position in a second direction (i.e., the direction in which the magnetic ball 10 rotates around the second axis 120).

[0071] As shown in FIG. 5, in an alternative embodiment of the present application, the magnetic ball 10 is controlled to rotate in a first direction by a first angle greater than 180°, and then, during the rotation of the magnetic ball 10, the three-dimensional magnetic field data (b x0 ,b y0 ,b z0 ), (b x1 ,b y1 ,b z1 )……(b xn ,b yn ,b zn ) is recorded. The position where the Z direction data of the magnetic field passes through the zero point is detected and set as the zero point position P0.

[0072] The angle of rotation when the magnetic ball 10 reaches the zero point position is acquired as α. The angle range of α is, for example, a left-closed / right-open interval of 0 to 2π.

[0073] x-direction component b at zero point position P0 xi and the y-direction component b yiThe angle between is β, and β=atan2(b yi ,b xi ) The x-direction component b xi and the y-direction component b yi Depending on the magnitude of the numerical value of β, β can include several cases such as:

[0074] b xi >0, β = arctan(b yi / b xi ). b yi ≧0, b xi <0, β = arctan(b yi / b xi )+π. b yi ≦0, b xi <0, β = arctan(b yi / b xi )-π. b yi ≧0, b xi If =0, then β=π / 2. b yi ≦0, b xi If =0, then β=-π / 2.

[0075] Here, the angle range of β is, for example, a left open / close right section from −π to π.

[0076] When the data change direction of the magnetic field strength at the zero point position P0 changes from positive to negative, the first calibration position of the magnetic ball 10 (i.e., the zero point of rotation around the first axis 110 of the magnetic ball 10) becomes V0=α-90°. At this time, the second calibration position of the magnetic ball 10 (i.e., the zero point of rotation around the second axis 120 of the magnetic ball 10) becomes H0=-β.

[0077] When the direction of change in the magnetic field strength data at the zero point position P0 changes from negative to positive, the first calibration position of the magnetic ball 10 is set to V0=α+90°, and the second calibration position of the magnetic ball 10 is set to H0=180°-β.

[0078] The first processing unit obtains a zero point position where the magnetic field strength in the Z-axis direction at a specific position is zero based on the detection data. Here, the second processing unit determines directional data of the zero point position P0 based on the detection data. The second processing unit is also used to obtain a first calibration position V0 and a second calibration position H0 of the magnetic ball 10 based on the zero point position P0, the directional data of the zero point position P0, and the detection data.

[0079] 6 is a schematic diagram of the magnetic ball 10 according to the embodiment of the present invention after calibration. As shown in FIG. 6, after the magnetic ball 10 according to the embodiment of the present invention is calibrated, the main axis of the magnetic ball 10 (i.e., the line on which the north and south magnetic poles are located) overlaps with the second axis 120.

[0080] In this embodiment, the zero point position P0 of the magnetic ball 10 is used as the calibration reference, and the data at this position has good discrimination, which effectively avoids the problem of insufficient calibration precision of the magnetic ball, reduces the influence of errors on the calibration results during the actual measurement process, and improves the calibration precision.

[0081] It should be explained that, in this specification, relational terms such as "first" and "second" are used solely to distinguish one entity or operation from another, without necessarily requiring or implying that any such actual relationship or order exists between those entities or operations. Furthermore, the terms "comprise," "comprises," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or device that includes a set of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such a process, method, article, or device. Absent further limitations, an element defined by the phrase "comprises one of" does not exclude the presence of other identical elements in a process, method, article, or device that includes that element.

[0082] According to the embodiments of the present application as described above, these embodiments do not detail all the details, and the present disclosure is not limited to the specific embodiments described. Obviously, many modifications and variations are possible based on the above description. The present application specifically describes these embodiments to better understand the principles and practical applications of the present application, thereby enabling those skilled in the art to utilize the present application and modify and use the present application. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. A method for calibrating a magnetic ball, comprising the steps of: A step of rotating the magnetic ball around a first axis by a first angle of 180° or more and acquiring detection data of three-axis magnetic field components at a detection position during the rotation; Based on the detection data, a zero point position P where the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero ０ and obtaining The detection data and the zero point position P ０ obtaining a calibration position of the magnetic ball based on the calibrating the magnetic ball based on the calibrated position of the magnetic ball; When the magnetic ball is located at the calibration position, the magnetization direction of the magnetic ball overlaps with a 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, A method for calibrating a magnetic ball, wherein the Z-axis magnetic field component is oriented in a direction that overlaps with the second axis, and the Y-axis magnetic field component is oriented in a direction that overlaps with the first axis.

2. Based on the detection data, the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero. ０ To get obtaining a plurality of sets of detection data relating to changes in magnetic field strength at detection positions during rotation of the magnetic ball about the first axis; obtaining a component of magnetic field strength in a second axis direction for each set of detection data based on the detection data; and It is determined whether the component of the magnetic field strength in the second axis direction is 0, and a zero point position P ０ 2. The method of claim 1, further comprising: obtaining a calibration coefficient of the magnetic ball.

3. Based on the detection data, the component of the magnetic field strength in the second axis direction of the magnetic ball becomes zero. ０ To get Based on the detection data, the position close to the zero point of the magnetic field component in the second axis direction is determined as the zero point approach position P １ and The zero point approach position P １ The zero point position P ０ 2. The method of claim 1, further comprising:

4. The detection data and the zero point position P ０ obtaining a calibration position of the magnetic ball based on In the process of the magnetic ball rotating around the first axis by the first angle, ０ determining the direction data of the The zero point position P ０ The direction data of the zero point position P ０ Based on the detection data, the first calibration position V ０ and the second calibration position H ０ 4. The method for calibrating a magnetic ball according to claim 2, further comprising obtaining:

5. The detection data and the zero point position P ０ In the case where the calibration position of the magnetic ball is calculated based on The zero point position P ０ When the direction data of V changes from positive to negative, the first calibration position is V ０ =α-90°, and the second calibration position is H ０ = -β, The zero point position P ０ When the direction data of V changes from negative to positive, the first calibration position is V ０ = α + 90°, and the second calibration position is H ０ = 180° - β, Here, the zero point position P ０ The three-axis magnetic field components at (b ｘｉ , b ｙｉ , b ｚｉ ) and α is the distance between the magnetic ball and the zero point position P ０ is the angle by which the rotation reaches β is the zero point position P ０ The x-direction component b ｘｉ and the y-direction component b ｙｉ 5. The method for calibrating a magnetic ball according to claim 4, wherein the angle is between.

6. A magnetic ball calibration device comprising: The magnetic ball has a magnetic pole along a main axis direction, and a calibration device for the magnetic ball includes: a first driving unit for driving the magnetic ball to rotate around a first axis by a first angle; a three-axis magnetic field sensor disposed adjacent to the magnetic ball for acquiring detection data of three-axis magnetic field components at a detection position during rotation of the magnetic ball; A zero point position P at which the magnetic field strength in the second axis direction at the detection position becomes zero based on the detection data is detected by the three-axis magnetic field sensor. ０ and the detection data and the zero point position P ０ and a data processing unit for obtaining a calibration position of the magnetic ball based on the calibration position of the magnetic ball, When the magnetic ball is located at the calibration position, the primary axis overlaps 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, A magnetic ball calibration device, characterized in that the Z-axis magnetic field component direction overlaps with the second axis direction, and the Y-axis magnetic field component overlaps with the first axis direction.

7. 7. The magnetic ball calibration device of claim 6, wherein the first angle is greater than or equal to 180 degrees or 200 degrees.

8. The data processing unit includes a first processing unit, The first processing unit obtains a component of magnetic field strength in the second axis direction of each set of detection data based on the detection data, and determines whether the component of magnetic field strength in the second axis direction is zero, and calculates a zero point position P where the component of magnetic field strength in the second axis direction is zero. ０ 7. The magnetic ball calibration device according to claim 6, wherein:

9. The data processing unit includes a first processing unit, The first processing unit determines a position close to the zero point of the magnetic field component in the second axis direction as a zero point approaching position P based on the detection data. １ and the zero point approach position P １ The zero point position P ０ 7. The magnetic ball calibration device according to claim 6, wherein:

10. The data processing unit includes a second processing unit, The second processing unit detects the zero point position P based on the detection data. ０ The direction data of the zero point position P ０ , the zero point position P ０ Based on the direction data and the detection data, the first calibration position V of the magnetic ball is determined. ０ and the second calibration position H ０ 10. The magnetic ball calibration device according to claim 8, further comprising:

11. the first axis or the second axis passes through the three-axis magnetic field sensor; 7. The magnetic ball calibration device according to claim 6, wherein the detection position includes a position where the three-axis magnetic field sensor is located.

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