Magnetic sensor calibration system, method and device

Abstract

The invention relates to a magnetic sensor calibration system, method and device, and the system comprises a magnetic source assembly and a rotating assembly. The magnetic source assembly is used for providing a working magnetic field and is connected with the rotating assembly; the rotating assembly is used for driving the magnetic source assembly to rotate, so that the magnetic source assembly can be located at at least two angle positions; the rotating center shaft of the magnetic source assembly is located in the working magnetic field, and in the process that the rotating assembly drives the magnetic source assembly to rotate, the relative pose relation among all components of the magnetic source assembly is fixed. Compared with the prior art, the magnetic sensor calibration system provided by the invention has the advantages that the structural design is simpler, and the intensity control of the magnetic field has less uncertainty in the process of adjusting the magnetic field direction of the working magnetic field. The problems that in the prior art, a magnetic sensor calibration system is complex in structure, and when a working magnetic field is controlled to calibrate a magnetic sensor, the calibration precision of the magnetic sensor is low due to more uncertainty are solved.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic navigation, and in particular to a magnetic sensor calibration system, method and device. Background Art

[0002] Electromagnetic navigation system (EMTS) is one of the mainstream surgical navigation system technology solutions. The most typical basic principle of EMTS is to generate a time-varying magnetic field through a field transmitter, detect the time-varying magnetic field through a magnetic sensor, and then calculate the position and posture of the magnetic sensor. There are many types of magnetic sensors, such as coil sensors based on the principle of electromagnetic induction, MEMS (micro-electromechanical system) magnetic sensor chips based on the Hall principle and magnetoresistance principle, etc. Among them, MEMS magnetic sensors are currently receiving more and more attention and applications due to their small size, high precision, direct output of three-axis magnetic field vector digital signals, low power consumption, easy integration and wireless application.

[0003] However, there are some errors when the magnetic sensor measures the three-dimensional magnetic field vector, so the magnetic sensor needs to be calibrated to correct the error. The current common magnetic sensor calibration system is composed of three groups of mutually orthogonal electromagnetic coils. By accurately controlling the coil current, the calibration system can generate working magnetic fields in various directions to measure and calibrate the magnetic sensor. Among them, the working magnetic field is an approximately uniform magnetic field within a certain range. Since the working magnetic field is the result of the joint action of the three groups of electromagnetic coils, when adjusting the working magnetic field, it is usually necessary to accurately control the current intensity of the three groups of electromagnetic coils separately, so that the control of the working magnetic field has at least three uncertainties.

[0004] In view of the complex structure of the magnetic sensor calibration system in the related technology, there is a lot of uncertainty when controlling the working magnetic field to calibrate the magnetic sensor, which makes it impossible to accurately control the working magnetic field, resulting in low calibration accuracy of the magnetic sensor. No effective solution has been proposed yet. Summary of the invention

[0005] The present invention provides a magnetic sensor calibration system, method and device to solve the problem that the magnetic sensor calibration system in the related art has a complex structure and has a lot of uncertainty when controlling the working magnetic field to calibrate the magnetic sensor, resulting in low calibration accuracy of the magnetic sensor.

[0006] In a first aspect, the present invention provides a magnetic sensor calibration system, the calibration system comprising: a magnetic source component and a rotating component;

[0007] The magnetic source component is used to provide a working magnetic field, and the magnetic source component is connected to the rotating component;

[0008] The rotating assembly is used to drive the magnetic source assembly to rotate so that the magnetic source assembly can be in at least two angular positions;

[0009] The rotation center axis of the magnetic source assembly is located inside the working magnetic field. During the process in which the rotating assembly drives the magnetic source assembly to rotate, the positional relationship between the components of the magnetic source assembly is relatively fixed.

[0010] In some of the embodiments, the magnetic source assembly includes two electromagnetic coils, the central axes of the two electromagnetic coils coincide, and the position relationship between the two electromagnetic coils is relatively fixed;

[0011] Alternatively, the magnetic source assembly includes a plurality of permanent magnets, the plurality of permanent magnets are distributed in a circular array, and the positional relationship between the plurality of permanent magnets is relatively fixed.

[0012] In some of the embodiments, the rotation center axis of the magnetic source assembly is located at the center of the working magnetic field and is perpendicular to the magnetic field direction of the working magnetic field.

[0013] In some of the embodiments, the rotating assembly includes a rotating table and a driving member;

[0014] The driving member is connected to the rotating table, and the driving member is used to drive the rotating table to rotate so that the rotating table can be in at least two angular positions;

[0015] The magnetic source assembly is fixedly mounted on the rotating platform.

[0016] In some embodiments, the magnetic source assembly includes two electromagnetic coils, the two electromagnetic coils are fixedly connected to the rotating table, and the two electromagnetic coils are symmetrically distributed on both sides of the rotating center axis of the rotating table;

[0017] Alternatively, the magnetic source assembly includes a plurality of permanent magnets, the plurality of permanent magnets are fixedly connected to the rotating table, and the plurality of permanent magnets are evenly distributed around the rotation center axis of the rotating table.

[0018] In some of these embodiments, the calibration system further comprises: a receiving component;

[0019] The containing assembly is used to provide a containing cavity capable of containing the calibrated object, and the containing cavity is covered by the working magnetic field.

[0020] In a second aspect, the present invention provides a magnetic sensor calibration method, which is applied to the magnetic sensor calibration system described in the first aspect, and the calibration method includes:

[0021] The magnetic source component is controlled to be in at least two angular positions respectively, and when the magnetic source component is in each of the angular positions, the working magnetic field provided by the magnetic source component is detected by a magnetic sensor to obtain magnetic field data corresponding to each of the angular positions; wherein the switching of different angular positions is realized by the rotating component driving the magnetic source component to rotate;

[0022] The magnetic sensor is calibrated according to the magnetic field data corresponding to each of the angular positions.

[0023] In some of the embodiments, the magnetic source assembly includes two electromagnetic coils;

[0024] The detecting the working magnetic field provided by the magnetic source component by means of a magnetic sensor comprises:

[0025] Providing a first current to the magnetic source component, detecting the working magnetic field through the magnetic sensor, and obtaining forward magnetic field data;

[0026] Providing a second current to the magnetic source component, detecting the working magnetic field through the magnetic sensor, and obtaining reverse magnetic field data;

[0027] The first current and the second current have the same strength and opposite directions.

[0028] In some embodiments, calibrating the magnetic sensor according to the magnetic field data corresponding to each of the angular positions includes:

[0029] Determine the target magnetic field data corresponding to each of the angular positions according to the difference between the forward magnetic field data and the reverse magnetic field data in the magnetic field data corresponding to each of the angular positions;

[0030] The magnetic sensor is calibrated according to the target magnetic field data corresponding to each of the angular positions.

[0031] In some of the embodiments, the at least two angular positions include at least two groups of angular positions, and each group of angular positions includes two angular positions that differ by 180°.

[0032] In some embodiments, calibrating the magnetic sensor according to the magnetic field data corresponding to each of the angular positions includes:

[0033] Determine the target magnetic field data corresponding to each group of the angular positions according to the difference between the magnetic field data corresponding to two of the angular positions in each group of the angular positions;

[0034] The magnetic field sensor is calibrated according to the target magnetic field data corresponding to each group of angular positions.

[0035] In a third aspect, the present invention provides a magnetic sensor calibration device, which is applied to the magnetic sensor calibration system described in the first aspect, and the calibration device includes:

[0036] A data acquisition module, used to control the magnetic source component to be in at least two angular positions respectively, and when the magnetic source component is in each of the angular positions, the magnetic sensor detects the working magnetic field provided by the magnetic source component to obtain magnetic field data corresponding to each of the angular positions; wherein the switching of different angular positions is achieved by the rotating component driving the magnetic source component to rotate;

[0037] The calibration module is used to calibrate the magnetic sensor according to the magnetic field data corresponding to each of the angular positions.

[0038] In a fourth aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the magnetic sensor calibration method described in the second aspect when executing the computer program.

[0039] In a fifth aspect, the present invention provides a storage medium on which a computer program is stored, and when the program is executed by a processor, the magnetic sensor calibration method described in the second aspect is implemented.

[0040] Compared with the related art, the magnetic sensor calibration system, method and device provided in the present invention have a simpler structural design than the prior art. In the process of adjusting the magnetic field direction of the working magnetic field, the intensity control of the magnetic field has only one uncertainty, and even no uncertainty is introduced. Compared with the existing magnetic sensor calibration system, it has less uncertainty and can more accurately control the magnetic field intensity of the working magnetic field, thereby improving the calibration accuracy of the magnetic sensor. It solves the problem that the magnetic sensor calibration system in the related art has a complex structure, has more uncertainties when controlling the working magnetic field to calibrate the magnetic sensor, and thus cannot accurately control the working magnetic field, resulting in low calibration accuracy of the magnetic sensor.

[0041] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0043] Figure 1 is a hardware structure block diagram of a terminal for executing the magnetic sensor calibration method of the present invention;

[0044] Figure 2 It is a structural schematic diagram of the magnetic sensor calibration system provided by the present invention;

[0045] Figure 3 is a vertical cross-sectional schematic diagram of a magnetic sensor calibration system in one embodiment of the present invention;

[0046] Figure 4 is a horizontal cross-sectional schematic diagram of a magnetic sensor calibration system in one embodiment of the present invention;

[0047] Figure 5 is a vertical cross-sectional schematic diagram of a magnetic sensor calibration system in another embodiment of the present invention;

[0048] Figure 6 is a horizontal cross-sectional schematic diagram of a magnetic sensor calibration system in another embodiment of the present invention;

[0049] Figure 7 is a flow chart of the magnetic sensor calibration method provided by the present invention;

[0050] Figure 8 is a flow chart of a magnetic sensor calibration method in a specific embodiment of the present invention;

[0051] Fig. 9 is a flow chart of a magnetic sensor calibration method in another specific embodiment of the present invention;

[0052] Fig.10 It is a structural block diagram of the magnetic sensor calibration device provided by the present invention. DETAILED DESCRIPTION

[0053] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0054] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0055] The method embodiment provided in this embodiment can be executed in a terminal, a computer or a similar computing device. For example, running on a terminal, Figure 1 FIG. 1 is a hardware structure diagram of a terminal for executing the magnetic sensor calibration method of the present invention. Figure 1 As shown, the terminal may include one or more ( Figure 1 Only one is shown in the figure) processor 102 and memory 104 for storing data, wherein processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The above terminal may also include a transmission device 106 and an input and output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the above terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations shown.

[0056] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the magnetic sensor calibration method in the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, to implement the above method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories may be connected to the terminal via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0057] The transmission device 106 is used to receive or send data via a network. The above network includes a wireless network provided by the communication provider of the terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, referred to as RF) module, which is used to communicate with the Internet wirelessly.

[0058] The present invention provides a magnetic sensor calibration system. Figure 2 Schematic diagram of the structure of the magnetic sensor calibration system provided by the present invention. Figure 2 As shown, the calibration system includes: a magnetic source component 100 and a rotating component 200; the magnetic source component 100 is used to provide a working magnetic field 300, and the magnetic source component 100 is connected to the rotating component 200; the rotating component 200 is used to drive the magnetic source component 100 to rotate so that the magnetic source component 100 can be in at least two angular positions; the rotation center axis 110 of the magnetic source component 100 is inside the working magnetic field 300, and in the process of the rotating component 200 driving the magnetic source component 100 to rotate, the relative posture relationship between the various components of the magnetic source component 100 is fixed.

[0059] In the magnetic sensor calibration system provided by the present invention, the magnetic source component 100 can provide a working magnetic field 300 when working. Among them, the working magnetic field 300 is an approximately uniform magnetic field whose uniformity is controlled within a small tolerance within a certain range. The coverage range of the working magnetic field 300 is mainly determined by the magnetic source component 100. For example, the difference between the central field strength and the edge field strength of the working magnetic field 300 can be controlled within 0.5%. Accordingly, other difference thresholds can be adopted according to the use requirements or technical height, such as controlling the difference within 1% or within 0.3%. When in use, the magnetic sensor is placed in the working magnetic field 300, and the magnetic field data of the working magnetic field 300 in different directions are detected respectively, so that the magnetic sensor can be calibrated by these magnetic field data. Specifically, the working magnetic field 300 is provided by the magnetic source component 100, and when the relative posture between the components in the magnetic source component 100 remains unchanged, the magnetic field strength of the working magnetic field 300 will remain stable. When the magnetic source component 100 is in different angular positions, working magnetic fields 300 in different directions are provided, and the magnetic field strengths of these working magnetic fields 300 are the same. Further, the magnetic source component 100 can be in at least two angular positions under the rotation drive of the rotating component 200, and the at least two angular positions can include the initial angular position of the magnetic source component 100 before rotation. Exemplarily, in a current calibration algorithm, the magnetic sensor is required to detect working magnetic fields 300 in more than 7 different directions, and the magnetic sensor is calibrated based on more than 7 sets of magnetic field data. Therefore, when the calibration algorithm is used, at least two angular positions include more than 7 angular positions. It should be noted that the calibration processes of different calibration algorithms are different. Therefore, when different calibration algorithms are used, the number of angular positions that the magnetic source component 100 can be in is different.

[0060] Exemplarily, when the magnetic source component 100 is a plurality of permanent magnets, when the relative positions between the plurality of permanent magnets are fixed, the magnetic field strength of the working magnetic field 300 provided by the plurality of permanent magnets will remain unchanged (the permanent magnet's own magnetic attenuation in the short term can be ignored). When the magnetic source component 100 is two electromagnetic coils, when the relative positions between the two electromagnetic coils are fixed, the magnetic field strength of the uniform magnetic strength provided by the two electromagnetic coils will remain unchanged (it is only necessary to keep the current intensity of the electromagnetic coils unchanged). The rotating component 200 is mainly used to drive the magnetic source component 100 to rotate. During the rotation process, the position relationship between the various components of the magnetic source component 100 is relatively fixed, that is, the rotating component 200 drives the magnetic source component 100 to rotate as a whole. Thus, when the magnetic source component 100 rotates, the magnetic field direction of the working magnetic field 300 provided by the magnetic source component 100 changes synchronously, and the magnetic field strength of the working magnetic field 300 remains unchanged. Therefore, in the magnetic sensor calibration system provided by the present invention, the magnetic source component 100 is driven to rotate as a whole by the rotating component 200, so as to adjust the magnetic field direction of the working magnetic field 300; at the same time, the magnetic source component 100 rotates as a whole, and does not affect the magnetic field strength of the working magnetic field 300. That is, the direction control and intensity control of the working magnetic field 300 are independent of each other, and the independent magnetic field strength control usually only needs to control at most one physical quantity to be realized. For example, when the magnetic source component 100 is two electromagnetic coils, it is only necessary to control the current intensity of the two electromagnetic coils. In the magnetic sensor calibration system in the prior art, it is necessary to control the current intensity of three groups (two in each group) of electromagnetic coils, that is, it is necessary to control at least three physical quantities.

[0061] It should be noted that, during the calibration of the magnetic sensor, the magnetic field direction of the working magnetic field 300 does not need to be precisely controlled, but only needs to be able to be at multiple different angles. Furthermore, in the present invention, the rotation control of the magnetic source assembly 100 does not introduce additional uncertainty. At the same time, the magnetic source assembly 100 is rotated in order to adjust the magnetic field direction of the working magnetic field 300, so there is an angle between the rotation center axis 110 of the magnetic source assembly 100 and the magnetic field direction of the working magnetic field 300.

[0062] Therefore, compared with the prior art, the magnetic sensor calibration system provided by the present invention has a simpler structural design. In the process of adjusting the magnetic field direction of the working magnetic field 300, the intensity control of the magnetic field has only one uncertainty, or even no uncertainty is introduced. Compared with the existing magnetic sensor calibration system, it has less uncertainty and can more accurately control the magnetic field intensity of the working magnetic field 300, thereby improving the calibration accuracy of the magnetic sensor. It solves the problem that the magnetic sensor calibration system in the related art has a complex structure and has more uncertainties when controlling the working magnetic field to calibrate the magnetic sensor, so that the working magnetic field cannot be accurately controlled, resulting in low calibration accuracy of the magnetic sensor.

[0063] Figure 3 is a vertical cross-sectional schematic diagram of a magnetic sensor calibration system in an embodiment of the present invention, Figure 4 Schematic diagram of a horizontal cross-section of a magnetic sensor calibration system in an embodiment of the present invention. Figure 3 and 4 In some embodiments, the magnetic source assembly 100 includes two electromagnetic coils 120, and the central axes of the two electromagnetic coils 120 coincide with each other (eg Figure 3 ), and the positional relationship between the two electromagnetic coils 120 is relatively fixed.

[0064] In the present embodiment, the working magnetic field 300 is composed of two parallel and opposite electromagnetic coils 120, and the central axes of the two electromagnetic coils 120 are coincident. When the two electromagnetic coils 120 conduct currents of the same strength, a working magnetic field 300 will be formed between the two electromagnetic coils 120, and the magnetic field direction of the working magnetic field 300 coincides with the central axis of the electromagnetic coil 120. Since the relative posture of the two electromagnetic coils 120 is fixed, the magnetic field strength of the working magnetic field 300 is only related to the current strength of the electromagnetic coil 120. Therefore, in the present embodiment, when the magnetic sensor calibration system is in use, only the current strength control of the electromagnetic coil 120 has uncertainty, that is, the magnetic sensor calibration system has only one uncertainty in the process of calibrating the magnetic sensor. Specifically, when the magnetic field strength of the working magnetic field 300 is kept constant, the current control of the electromagnetic coil 120 needs to be output at a constant current. Alternatively, the current control of the electromagnetic coil 120 performs a non-constant current output, but the time-varying characteristics of the coil current need to be measured. When the time-varying characteristics of the coil current are known, the time-varying characteristics of the magnetic field strength of the working magnetic field 300 can be determined, and the magnetic field strength information at the same time can be combined with the magnetic field data detected by the magnetic sensor to calibrate the magnetic sensor. Whether it is a constant current output or a time-varying characteristic of a non-constant current output, there is only one uncertainty.

[0065] Figure 5 is a vertical cross-sectional schematic diagram of a magnetic sensor calibration system in another embodiment of the present invention, Figure 6 FIG. 1 is a horizontal cross-sectional schematic diagram of a magnetic sensor calibration system in another embodiment of the present invention. Figure 5 and 6 In other embodiments, the magnetic source assembly 100 includes a plurality of permanent magnets 130 , which are distributed in a circular array, and the positional relationship between the plurality of permanent magnets 130 is relatively fixed.

[0066] In the present embodiment, the working magnetic field 300 is composed of a plurality of permanent magnets 130 distributed in a circular array, and the working magnetic field 300 is formed in the area surrounded by the plurality of permanent magnets 130. Among them, it is more critical that the relative posture relationship between the plurality of permanent magnets 130 is fixed, and then the magnetic field strength of the working magnetic field 300 provided by the plurality of permanent magnets 130 is fixed. During the rotation of the magnetic source assembly 100, the magnetic field strength of the working magnetic field 300 remains unchanged, and the magnetic field direction of the working magnetic field 300 changes synchronously with the rotation of the magnetic source assembly 100. Compared with the above-mentioned embodiment, the magnetic field strength control of the working magnetic field 300 in the present embodiment does not introduce uncertainty. Accordingly, it is only necessary to consider the magnetic attenuation effect of the permanent magnet 130 itself, but within the time period of a calibration process, the magnetic attenuation of the permanent magnet 130 can be ignored.

[0067] Reference Figure 2 , 3 and 5, in some of the embodiments, the rotation center axis 110 of the magnetic source assembly 100 is located at the center of the working magnetic field 300 and is perpendicular to the magnetic field direction of the working magnetic field 300 (the arrow indicates the magnetic field direction).

[0068] Specifically, the driving of the magnetic source assembly 100 to rotate is to change the magnetic field direction of the working magnetic field 300 provided by the magnetic source assembly 100, so that the magnetic sensor is in the working magnetic field 300, and the magnetic field data of the working magnetic field 300 in different directions can be detected. In order to better achieve the above effect, in this embodiment, the rotation center axis of the magnetic source assembly 100 is perpendicular to the magnetic field direction. For example, when the magnetic field direction of the working magnetic field 300 is horizontal, the rotation center axis of the magnetic source assembly 100 is in a vertical state, so that the rotation plane of the magnetic source assembly 100 is a horizontal plane. At the same time, when the rotation center axis 110 of the magnetic source assembly 100 is at the center of the working magnetic field 300, during the rotation of the magnetic source assembly 100, the spatial position of the middle area of ​​the working magnetic field 300 is fixed, and this part of the area can be used as the calibration work area of ​​the calibration system. Therefore, when in use, the calibrated object can be set in the calibration work area of ​​the calibration system, that is, the middle area of ​​the working magnetic field 300. At this time, during the rotation of the magnetic source assembly 100 , the working magnetic field 300 can always cover the object to be calibrated, and the object to be calibrated will not interfere with the rotation of the magnetic source assembly 100 .

[0069] Reference Figures 3 to 6 In some embodiments, the rotating assembly 200 includes a rotating table 210 and a driving member (not shown in the figure); the driving member is connected to the rotating table 210, and the driving member is used to drive the rotating table 210 to rotate so that the rotating table 210 can be in at least two angular positions; the magnetic source assembly 100 is fixedly mounted on the rotating table 210.

[0070] In this embodiment, the driving member can be a motor, and the output shaft of the motor can be connected to the rotating table 210 through a transmission structure such as a coupling and a reducer to drive the rotating table 210 to rotate. At the same time, the magnetic source assembly 100 is fixedly mounted on the rotating table 210. When the rotating table 210 rotates, the magnetic source assembly 100 can be driven to rotate synchronously. At this time, the rotation center axis of the rotating table 210 is the rotation center axis 110 of the magnetic source assembly 100. Usually, the rotating table 210 can be horizontally arranged, and its rotation plane is a horizontal plane. At this time, the magnetic source assembly 100 can be fixedly mounted on the upper surface of the rotating table 210.

[0071] Further, in an embodiment where the magnetic source assembly 100 includes two electromagnetic coils 120, the two electromagnetic coils 120 are fixedly connected to the rotating table 210, and the two electromagnetic coils 120 are symmetrically distributed on both sides of the rotation center axis of the rotating table 210. Specifically, the central axes of the two electromagnetic coils 120 coincide with each other and have the same size, so that a working magnetic field 300 can be formed, and the magnetic field direction of the working magnetic field 300 coincides with the central axis of the electromagnetic coil 120. The radial surface of the electromagnetic coil 120 is perpendicular to the rotating table 210, and the central axis of the electromagnetic coil 120 is parallel to the rotating table 210. Since the rotation center axis of the rotating table 210 is the rotation center axis 110 of the magnetic source assembly 100, when the two electromagnetic coils 120 are symmetrical to the rotation center axis of the rotating table 210, it can be ensured that the rotation center axis 110 of the magnetic source assembly 100 is at the center of the working magnetic field 300 and is perpendicular to the magnetic field direction of the working magnetic field 300. At the same time, the electromagnetic coil 120 is fixedly connected to the rotating platform 210, so that the relative position relationship between the two electromagnetic coils 120 is fixed.

[0072] Accordingly, in an embodiment in which the magnetic source assembly 100 includes a plurality of permanent magnets 130, the plurality of permanent magnets 130 are fixedly connected to the rotating table 210, and the plurality of permanent magnets 130 are evenly distributed on the circumferential side of the rotation center axis of the rotating table 210. Specifically, the plurality of permanent magnets 130 are distributed in a circular array, and the circular array is centered on the rotation center axis of the rotating table 210. A working magnetic field 300 can be formed in the area surrounded by the plurality of permanent magnets 130, and the rotation center axis of the rotating table 210 is at the center of the working magnetic field 300 and is perpendicular to the magnetic field direction of the working magnetic field 300. At the same time, the permanent magnets 130 are fixedly connected to the rotating table 210, and thus the relative posture relationship between the plurality of permanent magnets 130 is fixed.

[0073] It should be noted that, in the present invention, the magnetic source component 100 is to provide a working magnetic field 300. The two electromagnetic coils 120 and their configurations, as well as the multiple permanent magnets 130 and their configurations provided in the above embodiments are only exemplary illustrations of the magnetic source component 100. The focus of the present invention is to drive the magnetic source component 100 to rotate by the rotating component 200, thereby adjusting the magnetic field direction of the working magnetic field 300. Therefore, it should be understood that other devices that can provide a working magnetic field 300 can be used as the magnetic source component 100 in the present invention, and are not limited to the two electromagnetic coils 120 and their configurations, as well as the multiple permanent magnets 130 and their configurations provided in the above embodiments.

[0074] Reference Figure 3 and 5 In some of the embodiments, the calibration system further includes: a containing component 410; the containing component 410 is used to provide a containing cavity 420 that can contain the calibrated object, and the containing cavity 420 is covered by the working magnetic field 300.

[0075] In this embodiment, in order to place the calibrated object in the working magnetic field 300, a containing component 410 can be set in the coverage area of ​​the working magnetic field 300, and the containing component 410 has a containing cavity 420. When in use, the calibrated object can be placed in the containing cavity 420, and the calibrated object can be a magnetic sensor or a medical device containing a magnetic sensor. It should be noted that the containing component 410 is independent of the magnetic source component 100, that is, the containing component 410 does not rotate with the magnetic source component 100. During use, the spatial posture of the containing component 410 is fixed.

[0076] Further, the containing assembly 410 may be an extension of the mounting shell 400 of the calibration system. For example, in one embodiment, the calibration system has a mounting shell 400, the mounting shell 400 is a cavity structure, the magnetic source assembly 100 and the rotating table 210 are both mounted inside the mounting shell 400, so that the working magnetic field 300 can be formed inside the mounting shell 400 through the magnetic source assembly 100. At the same time, the middle part of the top wall of the mounting shell 400 can be recessed downward to form a container, and extend into the working magnetic field 300, and the container constitutes the containing assembly 410. The containing assembly 410 may also be an independent container that can be mounted on the mounting shell 400, for example, when the independent container is in use, it can be installed in a container formed by the recess of the mounting shell 400.

[0077] The present invention provides a magnetic sensor calibration method, which can be applied to the magnetic sensor calibration system provided by the present invention. Figure 7 is a flow chart of the magnetic sensor calibration method provided by the present invention, referring to Figure 7 , the calibration method includes the following steps:

[0078] Step S310, controlling the magnetic source assembly 100 to be at least two angular positions respectively, and when the magnetic source assembly 100 is at each angular position, detecting the working magnetic field 300 provided by the magnetic source assembly 100 through the magnetic sensor, and obtaining magnetic field data corresponding to each angular position; wherein the switching of different angular positions is realized by the rotating assembly 200 driving the magnetic source assembly 100 to rotate;

[0079] Step S320, calibrating the magnetic sensor according to the magnetic field data corresponding to each angular position.

[0080] In this technical solution, at least two angular positions may include the initial angular position of the magnetic source component 100, that is, the angular position of the magnetic source component 100 before being driven to rotate by the rotating component 200. Specifically, the control host mainly controls the rotation state of the magnetic source component 100 by controlling the rotating component 200, so that the magnetic source component 100 can be in at least two different angular positions respectively, and the at least two different angular positions may include the initial angular position of the magnetic source component 100, so that the working magnetic field 300 provided by the magnetic source component 100 can have at least two different directions respectively. Specifically, the rotating component 200 can be composed of a driving member and a rotating table 210, and the driving member can be a motor, and the output shaft of the motor can be connected to the rotating table 210 through a transmission structure such as a coupling and a reducer to drive the rotating table 210 to rotate. The control host can control the running state of the motor, thereby controlling the rotation state of the magnetic source component 100. Exemplarily, the rotation step and the rotation range may be set. The rotation step is the unit rotation angle of the magnetic source assembly 100. The magnetic source assembly 100 is periodically driven to rotate so that the magnetic source assembly 100 is in a plurality of different angular positions.

[0081] When in use, the magnetic sensor can be placed in the calibration work area of ​​the calibration system, that is, in the working magnetic field 300. The magnetic sensor can detect the working magnetic field 300 in real time to obtain the magnetic field data of the working magnetic field 300 in the current direction. In this step, when the magnetic source component 100 is at any angle position, after the reading of the magnetic sensor is stable, the control host will read the magnetic field data on the magnetic sensor, thereby obtaining the magnetic field data of the working magnetic field 300 detected by the magnetic sensor in the current direction. Finally, the control host can obtain multiple sets of magnetic field data of the working magnetic field 300 in different directions.

[0082] After the control host obtains the magnetic field data detected by the magnetic sensor when the magnetic source component 100 is at different angular positions, the magnetic field data can be calculated using the existing magnetic sensor calibration algorithm to calibrate the magnetic sensor.

[0083] The above steps mainly drive the magnetic source component 100 to rotate as a whole through the rotating component 200, so as to adjust the magnetic field direction of the working magnetic field 300; at the same time, the magnetic source component 100 rotates as a whole, and does not affect the magnetic field strength of the working magnetic field 300, that is, the direction control and strength control of the working magnetic field 300 are independent of each other. Specifically, in the magnetic sensor calibration process, the magnetic field direction of the working magnetic field 300 does not need to be precisely controlled, but only needs to be able to be at multiple different angles. Therefore, the control host will not introduce additional uncertainty in the rotation control of the magnetic source component 100. At the same time, for the magnetic field strength control of the working magnetic field 300, there will be only one uncertainty at most. For example, when the magnetic source component 100 adopts a permanent magnet 130, since the relative posture between each permanent magnet 130 is fixed, the magnetic field strength of the working magnetic field 300 is stable, and no additional control is required, that is, no uncertainty is introduced. When the magnetic source component 100 adopts an electromagnetic coil 120, the control host only needs to output a constant current to control the current of the electromagnetic coil 120. Alternatively, the host computer controls the current of the electromagnetic coil 120 to output a non-constant current, and the time-varying characteristics of the coil current also need to be measured. When the time-varying characteristics of the coil current are known, the time-varying characteristics of the magnetic field strength of the working magnetic field 300 can be determined, and the magnetic field strength information at the same time is combined with the magnetic field data detected by the magnetic sensor to calibrate the magnetic sensor. Whether it is a constant current output or a measurement of the time-varying characteristics of a non-constant current output, there is only one uncertainty.

[0084] Compared with the prior art, the magnetic sensor calibration method provided by the present invention has a simpler structural design. In the process of adjusting the magnetic field direction of the working magnetic field 300, the intensity control of the magnetic field has only one uncertainty, or even no uncertainty is introduced. Compared with the existing magnetic sensor calibration system, it has less uncertainty and can more accurately control the magnetic field intensity of the working magnetic field 300, thereby improving the calibration accuracy of the magnetic sensor. It solves the problem that the magnetic sensor calibration system in the related art has a complex structure, has more uncertainties when controlling the working magnetic field 300 to calibrate the magnetic sensor, and thus cannot accurately control the intensity of the working magnetic field, resulting in low calibration accuracy of the magnetic sensor.

[0085] Considering that there may be unknown magnetic fields in the natural environment, which may affect the detection result of the magnetic sensor on the working magnetic field 300 in the calibration system, the magnetic sensor calibration method of the present invention can also eliminate the influence of unknown magnetic fields.

[0086] Therefore, in some of the embodiments, the magnetic field data obtained by the magnetic sensor when the working magnetic field 300 is detected in two opposite directions can eliminate the influence of the unknown magnetic field. Since the magnetic field data detected by the magnetic sensor contains the magnetic field value of the unknown magnetic field, and the magnetic field direction and magnetic field value of the unknown magnetic field are fixed in the short term. Therefore, the magnetic field data obtained by the magnetic sensor when the working magnetic field 300 is detected in two opposite directions can be subtracted to eliminate the magnetic field value of the unknown magnetic field. At the same time, since the magnetic field values ​​of the working magnetic field 300 in opposite directions are in a positive and negative relationship, the magnetic field value of the working magnetic field 300 will be twice after the magnetic field data is subtracted. Furthermore, in the calibration process, it is necessary to form multiple groups of working magnetic fields 300 with opposite directions.

[0087] In some of the embodiments, the magnetic source component 100 includes two electromagnetic coils 120; in step S310, detecting the working magnetic field 300 provided by the magnetic source component 100 through the magnetic sensor includes: providing a first current to the magnetic source component 100, detecting the working magnetic field 300 through the magnetic sensor, and obtaining forward magnetic field data; providing a second current to the magnetic source component 100, detecting the working magnetic field 300 through the magnetic sensor, and obtaining reverse magnetic field data; wherein the first current and the second current have the same intensities and opposite directions.

[0088] Correspondingly, step S320, calibrating the magnetic sensor according to the magnetic field data corresponding to each angular position includes: determining the target magnetic field data corresponding to each angular position according to the difference between the forward magnetic field data and the reverse magnetic field data in the magnetic field data corresponding to each angular position; and calibrating the magnetic sensor according to the target magnetic field data corresponding to each angular position.

[0089] In this embodiment, since the magnetic source component 100 is composed of an electromagnetic coil 120, when the magnetic source component 100 is at any angular position, currents of opposite directions and the same strength can be applied to the electromagnetic coil 120, so that the electromagnetic coil 120 will form working magnetic fields 300 of the same strength and opposite directions. When the magnetic source component 100 is at any angular position, the magnetic field values ​​of the working magnetic field 300 in two opposite directions can be detected by a magnetic sensor, thereby obtaining two sets of magnetic field data, namely, forward magnetic field data and reverse magnetic field data. It should be noted that forward and reverse are only relative. When the magnetic field data of the working magnetic field 300 in a certain direction is determined to be forward magnetic field data, the magnetic field data of the corresponding working magnetic field 300 in the opposite direction is reverse magnetic field data. Specifically, the expressions of the two sets of magnetic field data are:

[0090]

[0091]

[0092] Among them, + s B ci is the magnetic field signal generated when the electromagnetic coil 120 conducts the first current at the i-th angular position, s B ci is the magnetic field signal generated when the electromagnetic coil 120 conducts the second current at the i-th angle position. It should be emphasized that the working magnetic field generated by the electromagnetic coil 120 s B ci Although the vector expression of will change with the angle, its modulus s B ci is unchanging. s B bg is the magnetic field signal of the unknown magnetic field, A is the internal parameter matrix of the sensor, which is a 3×3 matrix, expressing the change matrix of the sensor converting the actual physical quantity into the output signal, including the factors of the sensor's sensitivity of each axis, orthogonality, hard and soft magnetic interference terms. d The "zero drift" or "bias term" of the sensor indicates the zero input response of the sensor, that is, the value that the sensor still outputs in a completely non-magnetic environment. is the rotation matrix, which represents the transformation of the vector in the spatial coordinate system {s} to the sensor coordinate system {b}. b B pi It means that at angle i, the sensor measures the signal when the first current is turned on. b B ni It indicates the signal measured by the sensor when the second current is turned on at angle i; the subscript number i indicates the i-th angle position; the superscript b indicates the representation in the sensor coordinate system, and the superscript s indicates the representation in the space coordinate system. It can be seen from the above expression that the magnetic field data detected by the magnetic sensor contains the magnetic field signal of the unknown magnetic field. For the forward magnetic field data and reverse magnetic field data at any angle position, the difference processing is performed, and the difference calculation formula is as follows:

[0093]

[0094] b B i Represents the measured value (uncorrected) of the working magnetic field after removing the ambient magnetic field signal at the i-th angle, which is used for subsequent calibration calculations. The meanings of the subscripts and superscripts are as described above.

[0095] According to the calculation formula, after the excitation and difference processing of positive and negative square waves, the unknown environmental magnetic field interference can be eliminated, and the bias term is also eliminated. It should be noted that during the magnetic navigation calculation, the DC quantity in the magnetic field can be deducted by filtering, so the calibration of the bias term may not be performed in the navigation application. The above difference calculation result is the target magnetic field data, and finally the magnetic sensor is calibrated based on the target magnetic field data of the magnetic source component 100 at various angular positions.

[0096] In other embodiments, the at least two angular positions include at least two groups of angular positions, and each group of angular positions includes two angular positions that differ by 180°.

[0097] Correspondingly, step S320 calibrates the magnetic sensor according to the magnetic field data corresponding to each angular position, including: determining the target magnetic field data corresponding to each group of angular positions according to the difference between the magnetic field data corresponding to two angular positions in each group of angular positions; and calibrating the magnetic field sensor according to the target magnetic field data corresponding to each group of angular positions.

[0098] In this embodiment, two angular positions in the same group of angular positions are diagonal positions to each other. In a group of angular positions, two working magnetic fields 300 with opposite directions and the same strength can be provided respectively. By detecting these two working magnetic fields 300, two corresponding sets of magnetic field data can be obtained. Specifically, mainly by controlling the rotation of the magnetic source component 100, the magnetic source component 100 can be in multiple sets of diagonal positions. Furthermore, in this embodiment, multiple sets of working magnetic fields 300 with opposite directions can be formed. The magnetic field values ​​of the two working magnetic fields 300 with opposite directions are detected by the magnetic sensor respectively, so as to obtain two sets of magnetic field data. The two sets of magnetic field data can be calculated by the difference calculation formula in the previous embodiment, and the difference calculation result is the target magnetic field data, thereby eliminating the magnetic field value of the unknown magnetic field. Finally, the magnetic sensor is calibrated using at least two sets of target magnetic field data.

[0099] It should be noted that, no matter the magnetic source assembly 100 is composed of the electromagnetic coil 120 or the permanent magnet 130 , the rotation control method of the magnetic source assembly 100 in this embodiment can be used to form a working magnetic field 300 in the opposite direction.

[0100] The technical solution in this application is described below through some specific embodiments.

[0101] Reference Figure 3 and 4In one specific embodiment, the magnetic sensor calibration system includes: a mounting shell 400, two electromagnetic coils 120, a rotating table 210 and a calibration container (i.e., a containing component 410). The mounting shell 400 is a cavity structure, the rotating table 210 is installed at the lower position inside the mounting shell 400, and the two electromagnetic coils 120 are fixedly installed above the rotating table 210. The two electromagnetic coils 120 can be a Helmholtz coil pair, which can generate a working magnetic field 300 along the axial direction of the coil within a certain range inside the mounting shell 400, and the two electromagnetic coils 120 are symmetrically distributed about the rotation axis of the rotating table 210. A calibration container is arranged between the two electromagnetic coils 120, and the upper end of the calibration container is fixedly connected to the mounting shell 400. The working magnetic field 300 covers the middle and lower part of the calibration container, and the covered area of ​​the calibration container constitutes the calibration working area of ​​the calibration system (i.e., the containing cavity 420 of the containing component 410). Exemplarily, the width of the calibration work area can be 50mm-100mm, which is convenient for directly placing surgical instruments containing magnetic sensors. The two electromagnetic coils 120 are fixedly connected to the rotating table 210 and can rotate synchronously with the rotating table 210. The two electromagnetic coils 120 are also connected to a constant current source (not shown in the figure).

[0102] The magnetic sensor calibration method based on the above magnetic sensor calibration system mainly includes the following parts:

[0103] 1. Place the object to be calibrated.

[0104] The object to be calibrated can be a sensor plate or some surgical-related instruments containing sensors. The object to be calibrated can be placed directly in the calibration container on the mounting shell 400, or the object to be calibrated can be placed in an independent container first, and then the independent container is placed in the calibration container, so that the magnetic sensor is finally placed in the calibration working area. Among them, marks can be designed on the calibration container and the independent container, and the marks can indicate the range of the calibration working area, that is, the range covered by the working magnetic field 300 of the calibration container. Furthermore, the mounting shell 400, the calibration container and the independent container are all made of non-metallic materials. During calibration, the object to be calibrated can be placed in a special sterile independent container first, and then the independent container can be placed in the calibration container for calibration. Or the object to be calibrated can be placed directly in the calibration container through a sterile bag for calibration, thereby ensuring the sterility of the instrument.

[0105] 2. The two electromagnetic coils 120 are driven to a certain angle position by the rotating table 210, and then the positive and negative currents are sequentially conducted, and the corresponding magnetic field data are measured.

[0106] The rotating table 210 drives the two electromagnetic coils 120 to a certain angle position, but there is no special requirement for the accuracy of the angle position. The constant power supply maintains a constant output of the preset current, and switches the direction of the current through the drive module to generate positive and negative square wave signals. The magnetic sensor measures two sets of magnetic field values ​​after the signal stabilizes:

[0107]

[0108]

[0109] Among them, + s B ci is the magnetic field signal generated when the electromagnetic coil 120 conducts a forward current at angle i, s B ci is the magnetic field signal generated when the electromagnetic coil 120 conducts a reverse current at an angle i. s B bg is the magnetic field signal of the unknown magnetic field, A is the internal parameter matrix of the sensor, which is a 3×3 matrix, expressing the change matrix of the sensor converting the actual physical quantity into the output signal, including the factors of the sensor's sensitivity of each axis, orthogonality, hard and soft magnetic interference terms. d The "zero drift" or "bias term" of the sensor indicates the zero input response of the sensor, that is, the value that the sensor still outputs in a completely non-magnetic environment. is the rotation matrix, which represents the transformation of the vector in the spatial coordinate system {s} to the sensor coordinate system {b}. b B pi It means that at angle i, the sensor measures the signal when the first current is turned on. b B ni Indicates the signal measured by the sensor when the second current is turned on at angle i. The superscript b indicates the representation in the sensor coordinate system, and the superscript s indicates the representation in the space coordinate system. The serial number i indicates the i-th angle position. At each angle position, the electromagnetic coil 120 conducts positive and negative currents of the same strength and then performs magnetic field detection. The magnetic field data can be wirelessly output to the host, and then the difference calculation is performed:

[0110]

[0111] b B i Represents the measured value (uncorrected) of the working magnetic field after removing the ambient magnetic field signal at the i-th angle, which is used for subsequent calibration calculations. The meanings of the subscripts and superscripts are as described above.

[0112] According to the calculation formula, after the excitation and difference processing of positive and negative square waves, the unknown environmental magnetic field interference can be eliminated, and the bias term is also eliminated. It should be noted that when calculating magnetic navigation, the DC value in the magnetic field can be deducted by filtering, so the calibration of the bias term can be omitted in the navigation application.

[0113] 3. Determine whether data acquisition is completed.

[0114] The calibration algorithm does not need to accurately obtain the angular position of the two electromagnetic coils 120. It only needs to control a certain rotation step (such as 1 to 10 degrees) and a rotation range (such as 90 to 180 degrees). The above two sets of magnetic field values ​​are measured at each position, and the difference is calculated. When several sets of measurements at different angular positions are completed, data acquisition is completed.

[0115] 4. Calibrate the magnetic sensor.

[0116] The calibration algorithm can use traditional ellipse fitting, least squares method, optimization method, etc. to obtain the matrix A -1 The calibration method is described as follows:

[0117] Depend on Can be launched Taking the modulus values ​​on both sides, it can be simplified to: ( or Does not affect the modulus value). s B ci is a known constant, so A -1b B i 2 = s B ci 2 Expanding it, we can get an equation, combine multiple sets of measurement results (one equation for each angle position i), and form a system of equations to solve. Here, the superscript "-1" means inverting the matrix; represents the vector expressing the rotation matrix from the sensor coordinate system {b} to the space coordinate system {s}, The vector represents the rotation matrix from the spatial coordinate system {s} to the sensor coordinate system {b}; the symbol "" represents the modulus value; other descriptions are as above. The calibration algorithm is a well-known algorithm in the industry and is not the focus of this patent, so it will not be described here. It should be noted that due to the use of positive and negative pulses (or 180° difference) processing, there is no need to solve the bias B d .

[0118] The calibration method can use an online calibration method, such as RLS (Recursive Least Square), or wait until the data collection is completed. The calibration algorithm uses an existing calibration algorithm. After the calibration is completed, the calibration coefficient for a magnetic sensor will be sent to the navigation system and bound to the device for subsequent navigation calculations.

[0119] Reference Fig. 9 , provides a specific magnetic sensor calibration process. The magnetic sensor calibration process includes the following steps:

[0120] Step S410: Place the object to be calibrated.

[0121] The object to be calibrated may be a sensor plate or some surgical instruments containing sensors, etc. The object to be calibrated is placed in the calibration work area of ​​the magnetic sensor calibration system.

[0122] Step S420, rotating to a certain angle.

[0123] The two electromagnetic coils 120 are driven to a certain angle position by the rotating platform 210 .

[0124] Step S430, determining whether the limit is reached.

[0125] After the rotating platform 210 rotates to a certain angle position, it is necessary to determine whether the angle position reaches the limit position. If yes, step S470 is executed, and if no, steps S440 to S460 are executed.

[0126] Step S440, control the conduction current +I and read the magnetic field value b B pi .

[0127] Step S450, control the on-current -I and read the magnetic field value b B ni .

[0128] Step S460, calculating the magnetic field difference

[0129] Through the data acquisition and calculation of steps S440 to S460, the magnetic field data eliminating the interference of the unknown environmental magnetic field at the current angle position can be obtained. The specific calculation process and calculation principle can refer to the above description. After the magnetic field data acquisition and calculation of the current angle position are completed, step S420 is continued to rotate to the next angle position.

[0130] Step S470, calibrating the magnetic sensor.

[0131] When the rotation angle of the rotating stage 210 reaches the limit, it means that the rotating stage 210 has traversed enough angular positions, and the data acquisition is completed. i Enter the calibration algorithm to calibrate the magnetic sensor.

[0132] In this embodiment, the calibration system only includes two electromagnetic coils and a power supply. Current control requires constant current output (or non-constant current, but the current can be measured) plus switching drive (such as common motor drive, etc.). Therefore, compared with the multi-coil system, the calibration system in this embodiment has the following advantages:

[0133] 1. The current control is simpler, which reduces the uncertainty. Although the system requires the rotating table 210 to drive the electromagnetic coil 120 to rotate, there is no quantitative requirement for the accuracy and speed of the rotation, so no more uncertainty is introduced.

[0134] 2. The data acquisition mechanism and processing method eliminate the interference of unknown magnetic fields.

[0135] 3. The calibration work area of ​​the calibration system device is open and relatively easy to isolate, which is suitable for the calibration of sterile surgical instruments.

[0136] In another specific embodiment, a group of permanent magnets 130 can be used to replace the two electromagnetic coils 120 to provide the working magnetic field 300. The other parts of the calibration system are the same as the previous specific embodiment. The multiple permanent magnets 130 are fixed to each other. When the multiple permanent magnets 130 are combined in a certain way, it can be ensured that a relatively uniform magnetic field is generated in the middle area surrounded by the permanent magnets 130. The group of permanent magnets 130 can be driven to rotate by the rotating table 210, thereby changing the direction of the magnetic field. Figure 5 In a magnetic source assembly 100 composed of 8 permanent magnets 130 in a circular array, the magnetization direction of the top permanent magnet 130 is upward, and the magnetization directions of its adjacent left permanent magnet 130 and right permanent magnet 130 are respectively to the left and to the right, the magnetization directions of the two permanent magnets 130 in the middle are both downward, and the magnetization direction of the bottom permanent magnet 130 is upward, and the magnetization directions of its adjacent left permanent magnet 130 and right permanent magnet 130 are respectively to the right and to the left. In this combination, the magnetic source assembly 100 can form an upward working magnetic field 300. It should be noted that Figure 5 The figure shows only one combination of permanent magnets, which is a Halbach array, a well-known configuration in the industry. Other configurations can also be used in this embodiment, as long as the permanent magnet 130 can provide a working magnetic field 300.

[0137] Compared with the previous specific embodiment, this specific embodiment does not require current control. A set of permanent magnets 130 is manufactured and tested at the factory, and can remain stable for a period of time (non-extreme environment). This solution only has certain requirements on the rotation position of the rotating table 210. Specifically, a certain step length needs to be planned so that the permanent magnet 130 rotates one circle (360°), and for each angular position a, there is a corresponding position a+π. After the data is acquired, the preprocessing algorithm searches for the magnetic field value of the current angle b B a And its corresponding magnetic field value b B (a+π) , and then use the formula Finally, it is sent to the calibration algorithm for calibration to obtain the matrix A -1 .in: The subscript "a" indicates the measurement corresponding to the angle a, and the subscript "a+π" indicates the measurement corresponding to the angle a+π; s B pma represents the spatial representation of the working magnetic field generated by the permanent magnet 130 at the angle a, and s B pm(a+π) =- s B pma ; b B pma It represents the measured value of the working magnetic field after removing the influence of the environmental magnetic field at angle a (uncorrected); b is the "zero drift" or "bias term" of the sensor. The superscript b represents the representation in the sensor coordinate system, and the superscript s represents the representation in the space coordinate system. A is the internal parameter matrix of the sensor, is the rotation matrix, which means converting the vector in the spatial coordinate system {s} to the sensor coordinate system {b}. The direction of the working magnetic field changes with the rotation of the permanent magnet, so its vector expression in the spatial coordinate system changes with the angle, but its modulus s B pma is a known constant. Therefore, the subsequent processing is similar to the coil solution.

[0138] The uncertainty source of this specific embodiment is mainly the angle control of the motor. Since the calibration system does not have high requirements for the speed and the load is stable, the position accuracy control is easier to ensure. If an absolute position encoder is used, the angle accuracy can be easily controlled below 0.05°. The permanent magnet 130 group is relatively fixed, and there is no uncertainty in the independent rotation of multiple magnets.

[0139] Reference Fig.10 , provides another specific magnetic sensor calibration process. The magnetic sensor calibration process includes the following steps:

[0140] Step S510, placing the object to be calibrated.

[0141] The object to be calibrated may be a sensor plate or some surgical instruments containing sensors, etc. The object to be calibrated is placed in the calibration work area of ​​the magnetic sensor calibration system.

[0142] Step S520: Rotate to a certain angle.

[0143] A set of permanent magnets 120 is driven to a certain angle position by the rotating platform 210 .

[0144] Step S530, determining whether the preset direction range is completed.

[0145] During the rotation process, a certain step length (such as 10°) is planned so that the permanent magnet 130 rotates one circle (360°), and for each angular position a, there is a corresponding position a+π. This step is to determine whether the permanent magnet has completed one circle of rotation. If not, step S540 is executed, and if yes, step S550 is executed.

[0146] Step S540, record the current angle a and read the magnetic field value b B a .

[0147] After this step is completed, step S520 is continued to be executed. That is, step S520 to step S540 are executed cyclically. The rotating platform 210 drives the permanent magnet 120 to rotate according to the preset step length, and each time the rotating platform 210 rotates by a preset step length, step S530 and step S540 are executed once.

[0148] Step S550: preprocessing magnetic field data.

[0149] This step is executed when the permanent magnet completes one rotation. Within the range of one rotation, for each angular position a, there is a corresponding position a+π. The processing algorithm searches for the magnetic field value at the current angle. b B a And its corresponding magnetic field value b B (a+π) , and then use the formula Perform difference processing.

[0150] Step S470, calibrating the magnetic sensor.

[0151] The magnetic field difference at each angular position can be input into the calibration algorithm to calibrate the magnetic sensor.

[0152] The present invention also provides a magnetic sensor calibration device, which is used to implement the above-mentioned embodiments and preferred implementation modes, and will not be repeated hereafter. The terms "module", "unit", "subunit", etc. used below can implement a combination of software and / or hardware for a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0153] Figure 8 is a structural block diagram of the magnetic sensor calibration device provided by the present invention, such as Figure 8 As shown, the device comprises:

[0154] The data acquisition module 410 is used to control the magnetic source component to be at least two angular positions respectively, and when the magnetic source component is at each angular position, the magnetic sensor detects the working magnetic field provided by the magnetic source component to obtain the magnetic field data corresponding to each angular position; wherein the switching of different angular positions is realized by the rotating component driving the magnetic source component to rotate;

[0155] The calibration module 420 is used to calibrate the magnetic sensor according to the magnetic field data corresponding to each angular position.

[0156] Based on the above calibration device, the magnetic source component is mainly driven to rotate as a whole by the rotating component, so as to adjust the magnetic field direction of the working magnetic field; at the same time, the magnetic source component rotates as a whole, and does not affect the magnetic field strength of the working magnetic field, that is, the direction control and strength control of the working magnetic field are independent of each other. Specifically, in the magnetic sensor calibration process, the magnetic field direction of the working magnetic field does not need to be precisely controlled, and it only needs to be able to be at multiple different angles. Therefore, the rotation control of the magnetic source component by the control host will not introduce additional uncertainty. At the same time, there will be only one uncertainty at most for the magnetic field strength control of the working magnetic field. For example, when the magnetic source component adopts a permanent magnet, since the relative posture between the permanent magnets is fixed, the magnetic field strength of the working magnetic field is stable, and no additional control is required, that is, no uncertainty is introduced. When the magnetic source component adopts an electromagnetic coil, the control host only needs to perform constant current output for the current control of the electromagnetic coil. Alternatively, the control host performs non-constant current output for the current control of the electromagnetic coil, and it is also necessary to measure the time-varying characteristics of the coil current. Whether it is constant current output or measuring the time-varying characteristics of non-constant current output, there is only one uncertainty.

[0157] Compared with the prior art, the control of the working magnetic field is simpler, and in the process of adjusting the magnetic field direction of the working magnetic field, the control of the intensity of the magnetic field has less uncertainty. The problem of the magnetic sensor calibration method in the related art having more uncertainty when controlling the working magnetic field to calibrate the magnetic sensor is solved.

[0158] It should be noted that the above modules can be functional modules or program modules, and can be implemented by software or hardware. For modules implemented by hardware, the above modules can be located in the same processor; or the above modules can be located in different processors in any combination.

[0159] In this embodiment, an electronic device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor is configured to run the computer program to execute the steps in any one of the above method embodiments.

[0160] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor, and the input / output device is connected to the processor.

[0161] Optionally, in this embodiment, the processor may be configured to perform the following steps through a computer program:

[0162] S1, controls the magnetic source component to be in at least two angular positions respectively, and when the magnetic source component is in each angular position, detects the working magnetic field provided by the magnetic source component through the magnetic sensor to obtain the magnetic field data corresponding to each angular position; wherein, the switching of different angular positions is achieved by the rotating component driving the magnetic source component to rotate.

[0163] S2, calibrating the magnetic sensor according to the magnetic field data corresponding to each angular position.

[0164] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementation modes, and will not be repeated in this embodiment.

[0165] In addition, in combination with the magnetic sensor calibration method provided in the above embodiments, a storage medium may be provided in the present invention to implement the method. The storage medium stores a computer program, and when the computer program is executed by a processor, any one of the magnetic sensor calibration methods in the above embodiments is implemented.

[0166] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0167] It should be understood that the specific embodiments described herein are only used to explain the application, rather than to limit it. Based on the embodiments provided in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of this application.

[0168] Obviously, the drawings are only some examples or embodiments of the present application. For ordinary technicians in the field, the present application can also be applied to other similar situations based on these drawings without creative work. In addition, it is understandable that although the work done in this development process may be complicated and lengthy, for ordinary technicians in the field, certain changes in design, manufacturing or production based on the technical content disclosed in this application are only conventional technical means and should not be regarded as insufficient content disclosed in this application.

[0169] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0170] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A magnetic sensor calibration system, characterized in that: The magnetic sensor calibration system comprises: a magnetic source component (100) and a rotating component (200); The magnetic source component (100) is used to provide a working magnetic field (300), and the magnetic source component (100) is connected to the rotating component (200); The rotating assembly (200) is used to drive the magnetic source assembly (100) to rotate, so that the magnetic source assembly (100) can be in at least two angular positions; The rotation center axis (110) of the magnetic source component (100) is located inside the working magnetic field (300), and when the rotating component (200) drives the magnetic source component (100) to rotate, the positional relationship between the various components of the magnetic source component (100) is relatively fixed.

2. The magnetic sensor calibration system according to claim 1, characterized in that: The magnetic source assembly (100) comprises two electromagnetic coils (120), the central axes of the two electromagnetic coils (120) coincide with each other, and the position relationship between the two electromagnetic coils (120) is relatively fixed; Alternatively, the magnetic source assembly (100) comprises a plurality of permanent magnets (130), the plurality of permanent magnets (130) are distributed in a circular array, and the positional relationship between the plurality of permanent magnets (130) is relatively fixed.

3. The magnetic sensor calibration system according to claim 1, characterized in that: The rotation center axis (110) of the magnetic source component (100) is located at the center of the working magnetic field (300) and is perpendicular to the magnetic field direction of the working magnetic field (300).

4. The magnetic sensor calibration system according to claim 1, characterized in that: The rotating assembly (200) comprises a rotating platform (210) and a driving member; The driving member is connected to the rotating platform (210), and the driving member is used to drive the rotating platform (210) to rotate, so that the rotating platform (210) can be in at least two angular positions; The magnetic source assembly (100) is fixedly mounted on the rotating platform (210).

5. The magnetic sensor calibration system according to claim 4, characterized in that: The magnetic source assembly (100) comprises two electromagnetic coils (120), the two electromagnetic coils (120) are fixedly connected to the rotating platform (210), and the two electromagnetic coils (120) are symmetrically distributed on both sides of the rotating center axis of the rotating platform (210); Alternatively, the magnetic source assembly (100) comprises a plurality of permanent magnets (130), the plurality of permanent magnets (130) are fixedly connected to the rotating table (210), and the plurality of permanent magnets (130) are evenly distributed around the rotation center axis of the rotating table (210).

6. The magnetic sensor calibration system according to claim 1, characterized in that: The magnetic sensor calibration system further includes: a receiving component (410); The containing assembly (410) is used to provide a containing cavity (420) capable of containing a calibrated object, and the containing cavity (420) is covered by the working magnetic field (300).

7. A magnetic sensor calibration method, characterized in that: Applicable to the magnetic sensor calibration system according to any one of claims 1 to 6, the magnetic sensor calibration method comprising: The magnetic source component is controlled to be in at least two angular positions respectively, and when the magnetic source component is in each of the angular positions, the working magnetic field provided by the magnetic source component is detected by a magnetic sensor to obtain magnetic field data corresponding to each of the angular positions; wherein the switching of different angular positions is realized by the rotating component driving the magnetic source component to rotate; The magnetic sensor is calibrated according to the magnetic field data corresponding to each of the angular positions.

8. The magnetic sensor calibration method according to claim 7, characterized in that: The magnetic source assembly includes two electromagnetic coils; The detecting the working magnetic field provided by the magnetic source component by means of a magnetic sensor comprises: Providing a first current to the magnetic source component, detecting the working magnetic field through the magnetic sensor, and obtaining forward magnetic field data; Providing a second current to the magnetic source component, detecting the working magnetic field through the magnetic sensor, and obtaining reverse magnetic field data; The first current and the second current have the same strength and opposite directions.

9. The magnetic sensor calibration method according to claim 8, characterized in that: The calibrating the magnetic sensor according to the magnetic field data corresponding to each of the angular positions includes: Determine the target magnetic field data corresponding to each of the angular positions according to the difference between the forward magnetic field data and the reverse magnetic field data in the magnetic field data corresponding to each of the angular positions; The magnetic sensor is calibrated according to the target magnetic field data corresponding to each of the angular positions.

10. The magnetic sensor calibration method according to claim 7, characterized in that: The at least two angular positions include at least two groups of angular positions, and each group of angular positions includes two angular positions that differ by 180°.

11. The magnetic sensor calibration method according to claim 10, characterized in that: The calibrating the magnetic sensor according to the magnetic field data corresponding to each of the angular positions includes: Determine the target magnetic field data corresponding to each group of the angular positions according to the difference between the magnetic field data corresponding to two of the angular positions in each group of the angular positions; The magnetic field sensor is calibrated according to the target magnetic field data corresponding to each group of the angular positions.

12. A magnetic sensor calibration device, characterized in that: The magnetic sensor calibration system according to any one of claims 1 to 6, wherein the calibration device comprises: A data acquisition module, used to control the magnetic source component to be in at least two angular positions respectively, and when the magnetic source component is in each of the angular positions, the magnetic sensor detects the working magnetic field provided by the magnetic source component to obtain magnetic field data corresponding to each of the angular positions; wherein the switching of different angular positions is achieved by the rotating component driving the magnetic source component to rotate; The calibration module is used to calibrate the magnetic sensor according to the magnetic field data corresponding to each of the angular positions.

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