Adjustable multi-dipole magnetic field transmitting device and method for electromagnetic position tracking

Abstract

The embodiment of the application provides an adjustable multi-dipole magnetic field transmitting device and method for electromagnetic positioning and tracking, and belongs to the technical field of electromagnetic positioning and tracking. The device comprises a magnetic field transmitting source composed of three concentric and mutually different-axis solenoid coils, a driving circuit and a control unit. The control unit generates three mutually related aliasing current driving signals, each signal being superimposed by multiple different frequency components. By adjusting the amplitude of each frequency component, the magnetic moment components generated by the three coils at each frequency are combined into a synthetic magnetic moment vector with a direction and size that is independently adjustable, thereby simultaneously generating multiple independently adjustable dipole magnetic fields under a fixed physical structure. The application effectively solves the problem of poor flexibility of the magnetic field transmitting source in the existing electromagnetic positioning and tracking system and the difficulty in simultaneously generating multiple independently adjustable dipole magnetic fields, and has the advantages of compact structure, flexible control, rapid response and the like.

Description

Technical Field

[0001] This application relates to the field of electromagnetic positioning and tracking technology, and in particular to an adjustable multi-dipole magnetic field emitting device and method for electromagnetic positioning and tracking. Background Technology

[0002] In electromagnetic positioning and tracking systems, the magnetic field transmitter is the core component that generates alternating magnetic fields in space for sensors to calculate position and attitude. Traditional magnetic field transmitters often only produce a single, or a fixed-moment, dipole magnetic field. When multi-frequency, multi-directional alternating magnetic fields are required in complex positioning scenarios, existing technologies typically require complex mechanical transmission structures to physically rotate coils, or to deploy multiple independent single-frequency transmitters. This results in a bulky system, poor flexibility, high control complexity, and difficulty in achieving real-time dynamic adjustment of the magnetic field. Therefore, there is a need for a device that, with a fixed physical structure, can simultaneously generate multiple alternating dipole magnetic fields in space, each with independently adjustable magnetic moment direction and magnitude, through electrical control. Summary of the Invention

[0003] The main objective of this application is to propose an adjustable multi-dipole magnetic field emitting device and method for electromagnetic positioning and tracking, so as to solve the problems of poor flexibility of magnetic field emitting sources and difficulty in generating multiple independently adjustable dipole magnetic fields at the same time in the prior art.

[0004] To achieve the above objectives, one aspect of this application proposes an adjustable multi-dipole magnetic field emitting device for electromagnetic positioning and tracking, comprising: A magnetic field emission source, wherein the magnetic field emission source is composed of three independent solenoid coils that are concentric and non-axial; The driving circuit includes three driving channels, each driving channel being connected to and driving one of the solenoid coils, for power amplification of the current signal; The control unit is used to generate three interrelated current driving signals for three solenoid coils based on preset target magnetic field information. Each current driving signal is an aliased signal composed of multiple superimposed components of different frequencies. The control unit adjusts the amplitude of different frequency components in the aliased signal so that at each specific frequency, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector, and the direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby simultaneously generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

[0005] In some embodiments, the drive current of the three solenoid coils They are represented as follows:

[0006]

[0007]

[0008] in, to For n different frequencies, These are the amplitude coefficients of each frequency component in the three channels.

[0009] In some embodiments, at frequency Below, the resultant magnetic moment vector composed of the magnetic moment components generated by the three solenoid coils. The expression is:

[0010] in, For the composite magnetic moment vector The components of the X, Y, and Z axes in a rectangular coordinate system, The frequencies of the currents flowing through the three coils are respectively... The amplitude of the component, This represents the gain proportionality coefficient of coil A with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil B with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil C with respect to the magnetic moment X component. This represents the gain scaling factor of coil A with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil A with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Z component of the magnetic moment.

[0011] In some embodiments, the composite magnetic moment vector With the current in the three coils, the frequency is The magnitude vector of the component The following matrix transformation relationship is satisfied between them:

[0012] Where K is a 3×3 gain matrix, the elements of which are obtained through data calibration; the control unit is based on a preset target magnetic moment vector. The target current amplitude vector is obtained by inverting the gain matrix K, thereby determining the combination of amplitude coefficients of each frequency component in the driving current of the three coils.

[0013] In some embodiments, the control unit adjusts the number of equivalent dipole magnetic fields by adjusting the number n of different driving frequencies in the current driving signal.

[0014] In some embodiments, the preset target magnetic field information includes the number, frequency, magnitude, and direction of the multi-dipole magnetic field to be generated.

[0015] In some embodiments, the three solenoid coils of the magnetic field emitting source are placed orthogonally in pairs.

[0016] In some embodiments, the three solenoid coils of the magnetic field emitting source are placed at an angle that is not 0 degrees.

[0017] In some embodiments, the magnetic field emission source is a cylindrical solenoid, a square solenoid, or a spherical solenoid.

[0018] In some embodiments, the solenoid coil includes an iron core.

[0019] In some embodiments, the solenoid coil does not contain an iron core.

[0020] To achieve the above objectives, another aspect of this application proposes an adjustable multi-dipole magnetic field emission method for electromagnetic positioning and tracking, comprising the following steps: Three independent solenoid coils that are concentric and non-axial are provided, and the three coils are respectively connected to the three drive channels of the drive circuit; Based on the preset target magnetic field information, three interrelated current driving signals are generated, each of which is an aliased signal composed of multiple superimposed components of different frequencies. The current driving signal is amplified by a driving circuit to drive three solenoid coils respectively. By adjusting the amplitude of different frequency components in the aliased signal, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector at each specific frequency. The direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

[0021] In some embodiments, in the step of generating a synthetic magnetic moment vector at each specific frequency by adjusting the amplitude of different frequency components in the aliased signal, for the frequency... According to the preset target magnetic moment vector Through matrix transformation The frequency of the three coils was calculated to be The magnitude of the current component, where K is the gain matrix obtained in advance through data calibration.

[0022] In some embodiments, in the step of generating three interrelated current driving signals based on preset target magnetic field information, the current driving signals are digital signals, and the current driving signals are output to a digital-to-analog converter to be converted into analog signals before being input to the driving circuit.

[0023] In some embodiments, the number of equivalent dipole magnetic fields is adjusted by adjusting the number of different driving frequencies in the current driving signal.

[0024] The embodiments of this application include at least the following beneficial effects: This application provides an adjustable multi-dipole magnetic field transmitting device and method for electromagnetic positioning and tracking. This scheme generates three interrelated aliased current driving signals through a control unit and adjusts the amplitude of different frequency components in each signal, so that the magnetic moment components generated by three concentric and non-axial coils at each specific frequency are combined into a synthetic magnetic moment vector whose direction and magnitude can be independently adjusted. Thus, under the condition that the physical structure is completely fixed, the magnetic moment direction and magnitude of multiple equivalent dipole magnetic fields can be independently adjusted simultaneously. This avoids the problems of large system size and dynamic response lag caused by relying on mechanical rotating mechanisms or multiple independent transmitters in the prior art. Furthermore, frequency domain separation ensures that each dipole magnetic field does not interfere with each other, significantly improving the magnetic field flexibility, control accuracy, and environmental adaptability of the electromagnetic positioning and tracking system. Attached Figure Description

[0025] Figure 1 This is a physical schematic diagram of an adjustable multi-dipole magnetic field emitting device for electromagnetic positioning and tracking, as described in an embodiment of this application. Figure 2 This is a flowchart illustrating the steps of an adjustable multi-dipole magnetic field emission method for electromagnetic positioning and tracking in an embodiment of this application. Figure 3 This is a system block diagram of an adjustable multi-dipole magnetic field emitting device for electromagnetic positioning and tracking, as described in an embodiment of this application. Figure 4 This is a schematic diagram of the multi-dipole magnetic field frequency division synthesis of an adjustable multi-dipole magnetic field transmitting device for electromagnetic positioning and tracking, as described in an embodiment of this application. Detailed Implementation

[0026] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0027] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0028] In the description of this application, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0029] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0030] Electromagnetic positioning and tracking systems are a technology that calculates the position and attitude of a target object by detecting alternating magnetic fields in space. The basic principle is as follows: a magnetic field emitting device generates an alternating magnetic field with known characteristics in space; a magnetic field sensor attached to the target object detects the magnetic field vector information at various points; and the spatial position and attitude of the target object are deduced from the magnetic field model. Due to its advantages such as no line-of-sight obstruction, high accuracy, and good real-time performance, electromagnetic positioning and tracking systems have been widely used in fields such as medical navigation surgery, virtual reality interaction, industrial automation positioning, and robot pose tracking.

[0031] In electromagnetic positioning and tracking systems, the magnetic field transmitter is the core component that generates alternating magnetic fields in space for sensors to calculate position and attitude. To accurately calculate the six-degree-of-freedom pose of a target object, it is typically necessary to generate at least three alternating magnetic fields in different directions in space to provide sufficient spatial constraint information. Furthermore, with the increasing complexity of applications such as multi-target tracking and multi-task collaboration, higher demands are placed on the ability of the magnetic field transmitter to simultaneously generate alternating magnetic fields of multiple frequencies and directions.

[0032] Traditional magnetic field emitters often only generate a single dipole magnetic field, or one with a fixed magnetic moment direction and magnitude. Specifically, common single-frequency triaxial magnetic field emitters in existing technologies can generate magnetic fields in three orthogonal directions, but the frequencies of these three magnetic fields are the same, and the magnetic moment directions are fixed, making it impossible to independently adjust the magnetic moment direction at the same frequency. When multi-frequency, multi-directional alternating magnetic fields are needed in complex positioning scenarios, such as when it is necessary to provide positioning magnetic fields of different frequencies to multiple targets simultaneously to avoid mutual interference, existing technologies usually require complex mechanical transmission structures to physically rotate coils to change the magnetic moment direction, or to arrange multiple independent single-frequency emitters to provide multiple frequency components. This results in a large system size, poor flexibility, high control complexity, and difficulty in achieving real-time dynamic adjustment of the magnetic field.

[0033] Furthermore, while some existing technologies can generate composite frequency magnetic fields, they typically only involve the simple spatial superposition of magnetic field signals from multiple frequencies. They fail to achieve independent control over the direction and magnitude of the magnetic moment of the dipole magnetic field corresponding to each frequency, given a fixed physical structure. In other words, existing technologies lack a solution that can simultaneously generate multiple alternating dipole magnetic fields with independently adjustable magnetic moment directions and magnitudes using purely electrical methods within the same physical structure.

[0034] Therefore, there is an urgent need for a device that can simultaneously generate multiple alternating dipole magnetic fields in space with independently adjustable magnetic moment directions and magnitudes, under the premise of a fixed physical structure, through electrical control, in order to meet the increasingly complex electromagnetic positioning and tracking application requirements.

[0035] See Figure 1 This application provides an adjustable multi-dipole magnetic field emitting device for electromagnetic positioning and tracking, comprising: a magnetic field emitting source, a driving circuit, and a control unit.

[0036] The magnetic field emission source consists of three independent solenoid coils that are concentric and non-coaxial. The concentric placement of the three coils allows the magnetic fields generated by the three coils to be vector-synthesized in space with the same position as the reference point. The non-coaxial placement (including pairwise orthogonal or arbitrary non-zero angle placement) ensures that the directions of the magnetic moments generated by the three coils are linearly independent in space, thus enabling the synthesis of magnetic moment vectors pointing in any direction.

[0037] The driving circuit includes three driving channels, each of which is connected to and drives one of the solenoid coils. The driving circuit amplifies the current driving signal calculated by the control unit to generate driving currents for the three coils, thereby driving the three coils to produce a magnetic field that meets the amplitude and frequency requirements.

[0038] The control unit is used to generate three interrelated current drive signals for the three solenoid coils based on preset target magnetic field information, wherein each current drive signal is an aliased signal composed of multiple superimposed components of different frequencies. Each specific frequency corresponds to an alternating dipole magnetic field to be generated.

[0039] The control unit adjusts the amplitude of different frequency components in the aliased signal so that at each specific frequency, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector, and the direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby simultaneously generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

[0040] In one embodiment, the control unit adjusts the number of equivalent dipole magnetic fields by adjusting the number n of different driving frequencies in the current driving signal. When more dipole magnetic fields are needed, the number of frequency components in the driving signal is increased; when the dipole magnetic field is needed, the number of frequency components is decreased.

[0041] The preset target magnetic field information includes the number, frequency, magnitude, and direction of the multi-dipole magnetic field to be generated.

[0042] In one embodiment, the drive current of the three solenoid coils They are represented as follows:

[0043]

[0044]

[0045] in, to For n different frequencies, These are the amplitude coefficients of each frequency component in the three channels.

[0046] In one embodiment, at frequency Below, the resultant magnetic moment vector composed of the magnetic moment components generated by the three solenoid coils. The expression is:

[0047] in, For the composite magnetic moment vector The components of the X, Y, and Z axes in a rectangular coordinate system, The frequencies of the currents flowing through the three coils are respectively... The amplitude of the component, This represents the gain proportionality coefficient of coil A with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil B with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil C with respect to the magnetic moment X component. This represents the gain scaling factor of coil A with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil A with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Z component of the magnetic moment.

[0048] This formula can be simplified as follows:

[0049] Where K is a 3×3 gain matrix, the elements of which are obtained through data calibration; the control unit is based on a preset target magnetic moment vector. The target current amplitude vector is obtained by inverting the gain matrix K, thereby determining the amplitude coefficient combination of each frequency component in the driving current of the three coils. Taking the ideal case of the three coils being placed orthogonally in pairs as an example, the K matrix can be simplified to an identity matrix. It is easier to control.

[0050] As an optional embodiment of this application, the three solenoid coils of the magnetic field emission source can be arranged in pairs orthogonally or at any angle other than 0 degrees.

[0051] As an optional embodiment of this application, the magnetic field emission source can be a cylindrical solenoid, a square solenoid, or a spherical solenoid.

[0052] As an optional embodiment of this application, the solenoid coil of the magnetic field emitting source may or may not use an iron core. Using an iron core can enhance the magnetic field strength, while not using an iron core can avoid the nonlinear effects and eddy current losses associated with iron cores.

[0053] like Figure 2 As shown, this embodiment also provides an adjustable multi-dipole magnetic field emission method for electromagnetic positioning and tracking, including the following steps: Step S1: Provide three independent solenoid coils that are concentric and non-axial, and connect the three coils to the three drive channels of the drive circuit respectively.

[0054] Step S2: Based on the preset target magnetic field information, generate three interrelated current driving signals, each of which is an aliased signal composed of multiple superimposed components of different frequencies.

[0055] Specifically, the current drive signal is a digital signal, and the control unit outputs the current drive signal to the digital-to-analog converter to convert it into an analog signal before inputting it into the drive circuit.

[0056] Step S3: The current driving signal is amplified by the driving circuit to drive the three solenoid coils respectively.

[0057] Step S4: By adjusting the amplitude of different frequency components in the aliased signal, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector at each specific frequency. The direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

[0058] Specifically, regarding frequency According to the preset target magnetic moment vector Through matrix transformation The frequency of the three coils was calculated to be The magnitude of the current component, where K is the gain matrix obtained in advance through data calibration.

[0059] In one embodiment, the method further includes step S5: adjusting the number of equivalent dipole magnetic fields by adjusting the number n of different driving frequencies in the current driving signal.

[0060] The solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific application examples.

[0061] I. Device Structure In terms of structural form, the magnetic field emitting source described in this embodiment consists of three nested, mutually concentric and orthogonally wound independent solenoid coils. For example... Figure 1 As shown, the three solenoid coils are the first solenoid coil (coil A), the second solenoid coil (coil B), and the third solenoid coil (coil C). The three coils are concentrically nested on a spherical frame. Coil A is wound along the X-axis, coil B along the Y-axis, and coil C along the Z-axis, forming a tri-axis orthogonal spherical coil structure. This embodiment uses hollow coils without an iron core to avoid eddy current losses and nonlinear effects associated with iron cores, ensuring the linearity and stability of the magnetic field output.

[0062] This embodiment uses an STM32 microcontroller as the control unit and a USB peripheral to receive setting information from the host computer. Internally, the control unit generates digital current drive signals for three channels through digital signal processing. These digital signals are then converted into analog signals by a digital-to-analog converter (DAC) and input to the power amplifier circuit. The power amplifier circuit linearly amplifies the analog signals to generate sufficient drive current to supply the three solenoid coils. For example... Figure 3 As shown, the workflow of the entire system is as follows: the host computer sends the target magnetic field setting information to the control unit (STM32 microcontroller) via USB communication. The control unit calculates the digital quantity of the current drive signal of the three channels according to the setting information, converts it into an analog signal through a digital-to-analog converter, and drives the magnetic field emission source (three-axis coil) after power amplification by the drive circuit (power amplifier circuit), and finally generates the target magnetic field in space.

[0063] II. Control Principles The core control principle of this embodiment lies in the linear mapping relationship between the current flowing through the triaxial coils and the generated magnetic moment. For a concentrically placed triaxial coil system, at a specific frequency, the current amplitude of each of the three coils... Combined magnetic moment vector with space The relationship between them can be represented as:

[0064] in, K is a 3×3 gain matrix.

[0065] When the three coils are pairwise orthogonal and have identical parameters, the K matrix can be simplified to a diagonal matrix, and ideally, further simplified to an identity matrix. In this case, the current amplitudes of the three coils directly correspond to the magnetic moment components along the three axes, making control extremely simple. However, in practical engineering, due to factors such as coil winding errors and material inhomogeneities, the K matrix is ​​usually a non-diagonal matrix and needs to be obtained through data calibration.

[0066] When aliased current signals containing multiple frequency components are simultaneously injected into three coils, due to the linearity of the system, each frequency component independently generates a magnetic field of its corresponding frequency. Therefore, for a given frequency... ,have:

[0067] in, For the target magnetic field with frequency of The magnetic moment vector corresponding to the dipole magnetic field. The frequency of the driving current for the three coils is The vector formed by the magnitudes of the components.

[0068] Therefore, when it is necessary to generate n frequencies respectively The magnetic moment vectors are respectively To obtain an independent dipole magnetic field, simply inject the following aliased current signals into the three coils respectively:

[0069]

[0070]

[0071] in, .

[0072] III. Specific Control Examples The target magnetic field information set by the host computer is shown in Table 1 below: Table 1

[0073] In this embodiment, the three coils are orthogonal to each other and have essentially the same parameters, so the K matrix can be approximately simplified to an identity matrix. When K is the identity matrix, That is, the current amplitude of a specific frequency component in each coil is directly equal to the target magnetic moment component along the corresponding axis. From this, the expressions for the following three current signals A, B, and C can be derived:

[0074]

[0075]

[0076] Taking a frequency of 2000Hz as an example, the corresponding target magnetic moment vector is [1, 1, 1], which requires the generation of magnetic moment components with an amplitude of 1 in the X, Y, and Z axes. In the current expression, The amplitude of the 2000Hz component is 1. The amplitude of the 2000Hz component is 1. The amplitude of the 2000Hz component is 1. The magnetic moment components generated by the three coils at 2000Hz are combined into a single component pointing in the [1,1,1] direction with an amplitude of 1. The resultant magnetic moment vector. Similarly, the target magnetic moment vector corresponding to 2400Hz is [-1,1,1], which is combined into a resultant magnetic moment vector pointing in the direction of [-1,1,1]; the target magnetic moment vector corresponding to 2800Hz is [1,-1,2]; and the target magnetic moment vector corresponding to 4000Hz is [-1,-1,3].

[0077] Thus, the device simultaneously generates four equivalent dipole magnetic fields in space, corresponding to 2000Hz, 2400Hz, 2800Hz, and 4000Hz respectively. The magnetic moments of the four dipole magnetic fields are in different directions and their magnitudes are independently adjustable. Figure 4 As shown, Figure 4 In the diagram: the horizontal axis represents the frequency f, and the vertical axis represents the amplitude of the components of the magnetic moment vector M; the composite magnetic moment vectors corresponding to each frequency component point in different directions in three-dimensional space, and their amplitudes vary.

[0078] IV. Generation of Voltage Drive Signal Because solenoid coils have inductive impedance characteristics, in order to achieve the following: the currents passing through the three solenoid coils are respectively... A voltage signal of appropriate amplitude and phase needs to be applied to both ends of the coil. The impedance parameters of the triaxial coil in this embodiment are shown in Table 2 below: Table 2

[0079] Based on the coil impedance at each frequency, combined with the target current amplitude and phase, the required voltage amplitude and phase at each frequency can be calculated. The voltage amplitude equals the product of the current amplitude and the impedance magnitude, and the voltage phase equals the current phase plus the impedance angle. Taking all these factors into account, the voltage to be applied across the coil... as follows:

[0080]

[0081]

[0082] The voltage gain of the power amplifier circuit is 100, therefore, the analog voltage amplitude of the digital signal output by the control unit after digital-to-analog conversion should be 1 / 100 of the aforementioned voltage value. With a digital-to-analog converter conversion frequency of 40kHz, the highest frequency of interest for this device is 4000Hz, satisfying the Nyquist sampling theorem (the sampling frequency must be at least twice the highest frequency of the signal; 40kHz is much greater than 8kHz). For the four frequencies of 2000Hz, 2400Hz, 2800Hz, and 4000Hz, a complete minimum data cycle period is 5 milliseconds. At a sampling rate of 40kHz, this cycle contains 200 sampling points (n=0~199; taking n=0~99 as a half-cycle can also represent a complete waveform, the specific value to be determined based on actual calculation needs). The discrete expression of the digital signal is as follows (n=0,1,2,...,199):

[0083]

[0084]

[0085] The control unit continuously outputs these discrete digital quantities to the digital-to-analog converter at a rate of 40kHz. After power amplification, the converter drives the triaxial coil, which can simultaneously generate four independently controllable dipole magnetic fields in space.

[0086] In summary, compared with the prior art, this application has at least the following advantages and beneficial effects: 1) Flexible and adjustable magnetic field: This application adjusts the amplitude coefficient of different frequency components in the aliased signal by controlling the control unit. Under the premise that the physical structure is completely fixed, the magnetic moment direction and magnitude of multiple equivalent dipole magnetic fields can be independently adjusted without the need for any mechanical rotation structure, which greatly improves the flexibility and dynamic response speed of magnetic field emission.

[0087] 2) Simultaneous generation of multiple dipoles: This application can generate multiple equivalent dipole magnetic fields corresponding to different frequencies in space by simultaneously injecting current signals of multiple frequency components into a three-axis coil system. The dipole magnetic fields can be completely separated in the frequency domain and do not interfere with each other, providing an ideal magnetic field environment for multi-target electromagnetic positioning and tracking.

[0088] 3) Compact system structure: This application uses three concentric nested solenoid coils as the magnetic field emission source, eliminating the need for multiple independent single-frequency transmitters and complex mechanical rotation mechanisms. The system is small in size, light in weight, and highly integrated, making it easy to deploy in space-constrained application scenarios.

[0089] 4) High control precision: This application uses matrix transformation and A precise mapping relationship between the target magnetic moment and the driving current was established. The K matrix was obtained by combining the data calibration method, and precise decoupling control of multiple dipole magnetic fields was realized, effectively avoiding mutual interference between multiple frequency components.

[0090] 5) Frequency and number can be dynamically adjusted: This application can change the number of equivalent dipole magnetic fields by adjusting the number of frequency components in the driving signal. By setting different frequency values, the frequency of each dipole magnetic field can be changed, which can flexibly adapt to the dynamic requirements of magnetic field frequency and number in different application scenarios.

[0091] In the foregoing description of this specification, the references to terms such as "one embodiment," "another embodiment," or "some embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0092] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

[0093] The above is a detailed description of the preferred embodiments of this application, but this application is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An adjustable multi-dipole magnetic field emitting device for electromagnetic positioning and tracking, characterized in that, include: A magnetic field emission source, wherein the magnetic field emission source is composed of three independent solenoid coils that are concentric and non-axial; The driving circuit includes three driving channels, each driving channel being connected to and driving one of the solenoid coils, for power amplification of the current signal; The control unit is used to generate three interrelated current driving signals for three solenoid coils based on preset target magnetic field information. Each current driving signal is an aliased signal composed of multiple superimposed components of different frequencies. The control unit adjusts the amplitude of different frequency components in the aliased signal so that at each specific frequency, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector, and the direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby simultaneously generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

2. The apparatus according to claim 1, characterized in that, The driving current of the three solenoid coils They are represented as follows: in, to For n different frequencies, These are the amplitude coefficients of each frequency component in the three channels.

3. The apparatus according to claim 2, characterized in that, In frequency Below, the resultant magnetic moment vector composed of the magnetic moment components generated by the three solenoid coils. The expression is: in, For the composite magnetic moment vector The components of the X, Y, and Z axes in a rectangular coordinate system, The frequencies of the currents flowing through the three coils are respectively... The amplitude of the component, This represents the gain proportionality coefficient of coil A with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil B with respect to the magnetic moment X component. This represents the gain proportionality coefficient of coil C with respect to the magnetic moment X component. This represents the gain scaling factor of coil A with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Y component of the magnetic moment. This represents the gain proportionality coefficient of coil A with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil B with respect to the Z component of the magnetic moment. This represents the gain proportionality coefficient of coil C with respect to the Z component of the magnetic moment.

4. The apparatus according to claim 3, characterized in that, The combined magnetic moment vector With the current in the three coils, the frequency is The magnitude vector of the component The following matrix transformation relationship is satisfied between them: Where K is a 3×3 gain matrix, the elements of which are obtained through data calibration; the control unit is based on a preset target magnetic moment vector. The target current amplitude vector is obtained by inverting the gain matrix K, thereby determining the combination of amplitude coefficients of each frequency component in the driving current of the three coils.

5. The apparatus according to claim 1, characterized in that, The control unit adjusts the number of equivalent dipole magnetic fields by adjusting the number n of different driving frequencies in the current driving signal.

6. The apparatus according to claim 1, characterized in that, The preset target magnetic field information includes the number, frequency, magnitude, and direction of the multi-dipole magnetic field to be generated.

7. The apparatus according to claim 1, characterized in that, The three solenoid coils of the magnetic field emission source are placed orthogonally in pairs; or... The three solenoid coils of the magnetic field emission source are placed at any angle not equal to 0 degrees.

8. An adjustable multi-dipole magnetic field emission method for electromagnetic positioning and tracking, characterized in that, Includes the following steps: Three independent solenoid coils that are concentric and non-axial are provided, and the three coils are respectively connected to the three drive channels of the drive circuit; Based on the preset target magnetic field information, three interrelated current driving signals are generated, each of which is an aliased signal composed of multiple superimposed components of different frequencies. The current driving signal is amplified by a driving circuit to drive three solenoid coils respectively. By adjusting the amplitude of different frequency components in the aliased signal, the magnetic moment components generated by the three solenoid coils are combined into a composite magnetic moment vector at each specific frequency. The direction and magnitude of the composite magnetic moment vector corresponding to different frequencies are independently adjustable, thereby generating multiple equivalent dipole magnetic fields in space, each corresponding to a different frequency, with the direction and magnitude of the magnetic moment being independently adjustable.

9. The method according to claim 8, characterized in that, In the step of generating a synthetic magnetic moment vector at each specific frequency by adjusting the amplitude of different frequency components in the aliased signal, for the frequency... According to the preset target magnetic moment vector Through matrix transformation The frequency of the three coils was calculated to be The magnitude of the current component, where K is the gain matrix obtained in advance through data calibration.

10. The method according to claim 8, characterized in that, In the step of generating three interrelated current driving signals based on preset target magnetic field information, the current driving signals are digital signals, which are output to a digital-to-analog converter to be converted into analog signals and then input to the driving circuit.

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