Magnetic positioning system

Abstract

The invention discloses a magnetic positioning system, relates to the technical field of position detection and space positioning, and realizes high-precision positioning and dynamic tracking of a space target by constructing a composite magnetic signal based on a double-axis and single-axis rotating magnetic field and combining analytical modeling and a nonlinear optimization algorithm. The system is simple and compact in structure and efficient in operation, and the problems of high-frequency interference of traditional electromagnetic positioning and difficult solving of a low-frequency algorithm are solved. A single-shaft rotating permanent magnet is added on a revolution shaft to change magnetic field time sequence characteristics, so that the difference of magnetic field vector sequences corresponding to different spatial positions is remarkable, and the probability of occurrence of multiple solutions is reduced. Through double magnetic field source joint matching residual error judgment, rapid elimination of fuzzy solutions is realized, and positioning uniqueness and calculation efficiency are improved. The system is integrally kept compact, is low in power consumption, and is suitable for virtual / augmented reality, medical navigation, robot positioning and other scenes requiring high precision.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of position detection and spatial positioning, and in particular to a magnetic positioning system based on rotating permanent magnets. BACKGROUND

[0002] Position detection and spatial positioning technology is widely used in virtual reality, augmented reality, robot navigation, medical surgery navigation, precision assembly and motion capture fields. The existing common methods include optical positioning, inertial measurement positioning, ultrasonic positioning and magnetic field positioning. Optical positioning has high accuracy but is easily affected by occlusion and light conditions; inertial measurement does not require external signals but has error accumulation; ultrasonic positioning has low cost and is simple to implement, but is greatly affected by environmental noise and medium changes.

[0003] Magnetic field positioning technology can work stably in complex environments and closed spaces due to the characteristics of magnetic field that can penetrate non-metallic materials and is not affected by occlusion. Magnetic positioning systems based on rotating permanent magnets generating time-varying magnetic fields have attracted attention due to stable magnetic field sources, low power consumption and compact structure. A common design is to make the permanent magnet rotate around two intersecting rotation axes to form a time-varying magnetic field distribution in space. The position can be calculated by model inversion after the sensor measures the three components of the magnetic field. In such a dual-axis rotating magnetic field system, the eccentric arrangement of the permanent magnet can break the symmetry of the magnetic field and achieve unique three-dimensional position calculation within a certain range.

[0004] However, the magnetic field positioning system in the prior art has low discrimination of magnetic field signals generated at different spatial positions, which affects the positioning accuracy. SUMMARY

[0005] In view of the above problems, the present application provides a magnetic positioning system for overcoming the above problems or at least partially solving the above problems. The system utilizes the time-varying magnetic field generated by the permanent magnet under multi-degree-of-freedom rotation to achieve high-precision positioning of the target sensor in space.

[0006] The present application provides the following solutions: A magnetic positioning system, comprising: a magnetic field generator, the magnetic field generator comprising a dual-axis rotating permanent magnet and a single-axis rotating permanent magnet, the dual-axis rotating permanent magnet being configured to rotate around two mutually perpendicular and non-coplanar axes to generate a spatially non-uniform time-varying magnetic field; the rotation axis of the single-axis rotating permanent magnet is coaxial or coupled with a certain axis of the dual-axis rotating permanent magnet rotation structure, and independently rotates around its own axis to generate an additional magnetic field, which is used to superimpose with the time-varying magnetic field to destroy the symmetry of the magnetic field distribution and obtain a composite time-varying magnetic field; a magnetic field sensor arranged in an object to be measured, the magnetic field sensor being used to measure three-dimensional magnetic field component data at a target spatial position; a computing unit configured to execute a positioning method, the positioning method comprising: determining that the dual-axis rotating permanent magnet and the single-axis rotating permanent magnet are working synchronously to generate the composite time-varying magnetic field, obtaining magnetic field three-component data synchronously collected by the magnetic field sensor in a sampling period, and obtaining angle information of the dual-axis rotating permanent magnet and the single-axis rotating permanent magnet; calculating a candidate position set of the target based on a back-solving equation of a magnetic dipole model using the magnetic field three-component data and the angle information; using an additional magnetic field sequence introduced by the single-axis rotating permanent magnet to superimpose matching degree judgment of the additional magnetic field sequence in the solution, so as to eliminate solutions that do not meet the joint timing characteristics of the dual magnetic fields; selecting a unique solution with the smallest residual and the highest consistency as the unique positioning result by comparing the residual of the theoretical magnetic field response and the measured response of several initial estimated values in the candidate position set under two sets of magnetic field sources through a residual function; outputting the unique positioning result and performing smoothing processing and dynamic tracking according to the time sequence correlation of continuous measurement.

[0007] Preferably, the residual function is represented by the following formula:

[0008] In the formula, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value.

[0009] Preferably, the initial estimated value is obtained by back-solving the following formula:

[0010]

[0011]

[0012] In the formula, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, B represents a residual comparison value, represents an auxiliary variable, represents the height of the single-axis rotating permanent magnet in the axial direction.

[0013] Preferably: utilize time series dynamic consistency judgment and nonlinear optimization algorithm to select the unique solution with the smallest residual and the highest consistency as the unique positioning result.

[0014] Preferably: the nonlinear optimization algorithm includes algorithm, the algorithm is used for six-degree-of-freedom solution refinement of the initial estimate.

[0015] Preferably: the rotation axis of the single-axis rotating permanent magnet coincides with one of the rotation axes of the double-axis rotating permanent magnet.

[0016] Preferably: the double-axis rotating permanent magnet and the single-axis rotating permanent magnet are both connected with an angle encoder, and the angle encoder is used to acquire the angle information.

[0017] Preferably: further comprising a control unit, the control unit is used to drive the rotation of the permanent magnet and synchronously collect the magnetic field and angle information; the control unit and the magnetic field sensor and the angle encoder realize time synchronization in a time stamp synchronization mode.

[0018] Preferably: the magnetic field generator further comprises a mounting base and a driving motor, the mounting base is provided with a first bevel gear, the output shaft of the driving motor extends to the upper side of the first bevel gear through the mounting base and the first bevel gear, the double-axis rotating permanent magnet is connected with a second bevel gear and a third bevel gear respectively, the second bevel gear and the third bevel gear are rotatably connected with a fixed connecting shaft respectively, the fixed connecting shaft is connected with the output shaft in an axial vertical manner through a shaft sleeve, and the single-axis rotating permanent magnet is connected with the top of the output shaft.

[0019] According to the specific embodiments of the present application, the following technical effects are disclosed: The magnetic positioning system provided by the embodiments of the present application constructs a composite magnetic signal based on a double-axis plus single-axis rotating magnetic field, combines analytical modeling and nonlinear optimization algorithm, and realizes high-precision positioning and dynamic tracking of a space target. The system has a simple and compact structure and high operation efficiency, avoids the problems of high-frequency interference and low-frequency algorithm solution difficulty in traditional electromagnetic positioning. By adding a single-axis rotating permanent magnet on the revolution axis to change the timing characteristics of the magnetic field, the difference of the magnetic field vector sequence corresponding to different space positions is significantly different, and the probability of multiple solutions is reduced. Through joint matching residual judgment of the double magnetic field sources, the fuzzy solution is quickly eliminated, and the uniqueness of positioning and the calculation efficiency are improved. The overall system is compact and low in power consumption, and is suitable for virtual / augmented reality, medical navigation, robot positioning and other high-precision scenarios.

[0020] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0022] Figure 1 This is a schematic diagram of the magnetic positioning system provided in an embodiment of the present invention; Figure 2 This is an assembly diagram of the magnetic field generator provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of an exemplary mathematical model of the magnetic positioning system provided in an embodiment of the present invention; Figure 4 This is an algorithm flowchart provided in an embodiment of the present invention.

[0023] In the figure: Magnetic field generator 1, dual-axis rotating permanent magnet 11, single-axis rotating permanent magnet 12, mounting base 13, drive motor 14, first bevel gear 15, second bevel gear 16, third bevel gear 17, fixed connecting shaft 18, magnetic field sensor 2, object to be measured 3, computing unit 4, control unit 5, base station module 6, orbital trajectory 7. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0025] See Figure 1 This invention provides a magnetic positioning system, such as... Figure 1 As shown, the system may include: A magnetic field generator 1, comprising a biaxial rotating permanent magnet 11 configured to be rotatable around two mutually perpendicular and non-coplanar axes to generate a spatially non-uniformly varying time-varying magnetic field, and a uniaxial rotating permanent magnet 12, the rotation axis of which is configured to be coaxial with or coupled to a certain axis of the biaxial rotating permanent magnet 11 rotation structure and independently rotatable around its own axis to generate an additional magnetic field used to superimpose with the time-varying magnetic field to destroy the symmetry of the magnetic field distribution and obtain a composite time-varying magnetic field; the purpose of destroying the symmetry of the magnetic field is to improve the uniqueness of the magnetic vector in space and enhance the distinguishability of the magnetic response sequence between different position points, effectively eliminating the mirror ambiguity caused by symmetry.

[0026] In a specific implementation, the rotation axis of the uniaxial rotating permanent magnet 12 can coincide with one of the rotation axes of the biaxial rotating permanent magnet 11. Both the biaxial rotating permanent magnet 11 and the uniaxial rotating permanent magnet 12 are connected with an angle encoder with a resolution of not less than 0.1°, which is used to obtain the angle information.

[0027] A magnetic field sensor 2 is arranged in an object 3 to be measured, which is used to measure three-dimensional magnetic field component data at a target spatial position; the measurement range of the magnetic field sensor 2 covers ±1000µT.

[0028] The magnetic field generator 1 provided by the embodiments of the present application can adopt various structural forms. For example, in one example, the magnetic field generator 1 further comprises a mounting base 13 and a driving motor 14, the mounting base 13 is provided with a first bevel gear 15, the output shaft of the driving motor 14 extends through the mounting base 13 and the first bevel gear 15 to above the first bevel gear 15, the biaxial rotating permanent magnet 11 is connected with a second bevel gear 16 and a third bevel gear 17 respectively, the second bevel gear 16 and the third bevel gear 17 are rotatably connected with a fixed connecting shaft 18 respectively, the fixed connecting shaft 18 is connected with the output shaft in an axially perpendicular manner through a shaft sleeve, and the uniaxial rotating permanent magnet 12 is connected with the top of the output shaft.

[0029] In order to further realize time synchronization, the control unit 5 can be used to drive the rotation of the permanent magnet and synchronously collect the magnetic field and angle information; the control unit 5 and the magnetic field sensor 2 and the angle encoder realize time synchronization in a time stamp synchronization manner.

[0030] A computing unit 4 is used to execute a positioning method, the positioning method comprising: After determining that the dual-axis rotating permanent magnet 11 and the single-axis rotating permanent magnet 12 work synchronously to generate the composite time-varying magnetic field, three-component magnetic field data synchronously collected by the magnetic field sensor 2 in a sampling period are obtained, and angle information of the dual-axis rotating permanent magnet 11 and the single-axis rotating permanent magnet 12 is obtained. A candidate position set of the target is calculated based on a back solution equation of a magnetic dipole model by using the three-component magnetic field data and the angle information. The matching degree of the additional magnetic field sequence introduced by the single-axis rotating permanent magnet 12 is superimposed in the solution, so as to eliminate solutions that do not meet the joint time sequence characteristics of the dual magnetic fields; the residual error of the theoretical magnetic field response and the measured response of several initial estimated values in the candidate position set under two sets of magnetic field sources is compared through a residual function, and the unique solution with the smallest residual error and the highest consistency is selected as the unique positioning result. The unique positioning result is output, and smoothing processing and dynamic tracking are performed according to the time sequence correlation of continuous measurement.

[0031] The magnetic positioning system provided by the embodiment of the application aims to realize six-degree-of-freedom position and attitude measurement with high reliability and high precision. The system is composed of a magnetic field generator, an additional rotating unit, a magnetic field measurement unit, and a computer device. The magnetic field generator adopts a dual-axis rotating mechanism, and a permanent magnet is driven by a driving assembly to rotate around two intersecting axes, so as to form a dynamically changing dual-axis magnetic field distribution; at the same time, a single-axis rotating permanent magnet 12 is arranged on the revolution axis to generate an additional magnetic field disturbance and enhance the uniqueness of the positioning feature. In order to improve the accuracy of the system solution, the application proposes a solution algorithm combined with dual-source magnetic fields, and through three-axis magnetic field data and rotating angle information collected by a magnetic sensor, filtering processing, candidate position solution, and fuzzy solution elimination steps are performed, and finally a unique positioning result with the best consistency is output.

[0032] The magnetic positioning method provided by the embodiment of the application introduces auxiliary information through an additional magnetic field on the basis of magnetic field sequence feature modeling, effectively improves the multi-solution determination capability, and at the same time, the system structure is compact, supports a periodic and low-frequency magnetic field working mode, has strong anti-interference performance, and is suitable for precise positioning tasks in complex spatial environments such as virtual / augmented reality, medical navigation, and robot end positioning.

[0033] The magnetic positioning system and the positioning method provided by the application will be described in detail below.

[0034] The space positioning system based on double-rotating permanent magnet includes a double-axis rotating magnetic field generating unit and a single-axis rotating permanent magnet 12 configuration of the orbit axis, and cooperates with a set of magnetic field positioning ambiguity elimination solution algorithm to realize high-precision analysis of the target position in three-dimensional space. The system combines the double-axis rotating magnetic field with the single-axis rotating permanent magnet 12 on the orbit axis, changes the distribution characteristics of the magnetic field, makes the magnetic field signals generated at different space positions have higher distinguishability, and thus improves the reliability and accuracy of the positioning calculation. The system comprises: The magnetic field generator 1 is composed of a bearing assembly and a driving assembly. The bearing assembly defines a first rotation axis and provides a first permanent magnet, and the driving assembly drives the first permanent magnet to rotate around the first rotation axis and a second rotation axis intersecting with the first rotation axis, forming a double-axis rotating time-varying magnetic field. A single-axis rotating permanent magnet 12 is arranged on the second rotation axis, which rotates around its own axis to generate an additional time-varying magnetic field, which is superimposed with the double-axis rotating magnetic field to change the time sequence characteristics of the magnetic field vector.

[0035] The double-axis rotating permanent magnet 11 is arranged to rotate around two perpendicular axes to generate a spatially non-uniformly changing magnetic field; the double-axis rotating permanent magnet 11 rotates around two mutually perpendicular and non-coplanar rotation axes to form a non-periodic magnetic field.

[0036] The single-axis rotating permanent magnet 12 has its rotation axis arranged coaxially or coupled with a certain axis of the first permanent magnet rotating structure, and can independently rotate around its own axis to superimpose an additional time-varying magnetic field signal; the rotation axis of the single-axis rotating permanent magnet coincides with one of the rotation axes of the first permanent magnet of the double-axis rotating permanent magnet 11, and the generated magnetic field is used to modulate the frequency domain characteristics of the original magnetic field.

[0037] The single-axis rotating permanent magnet 12 is used to introduce specific frequency and phase modulation information, thereby destroying the symmetry of the magnetic field distribution, improving the uniqueness of the magnetic vector in space, enhancing the distinguishability of the magnetic response sequence between different position points, and effectively eliminating the mirror ambiguity caused by symmetry.

[0038] An angle encoder is arranged on the permanent magnet and is used to collect angle information and magnetic moment direction of each rotating magnet in real time; the angle encoder includes a capacitive or photoelectric rotary encoder, and the resolution is not less than 0.1°.

[0039] A magnetic field sensor 2 is used to measure three-dimensional magnetic field component data at the target space position; the magnetic field sensor 2 adopts an AMR or TMR type and has three-axis measurement capability, and the measurement range covers ±1000µT.

[0040] The control unit 5 is used for driving rotation of the permanent magnet and synchronously collecting magnetic field and angle information; the control unit 5 and the magnetic field sensor 2 and the angle encoder adopt a time stamp synchronous mode, so as to ensure one-to-one correspondence of data.

[0041] The following introduces a specific implementation of a system arrangement.

[0042] The system comprises a magnetic field generator 1, a controller, a magnetic field sensor 2, an angle encoder, a computing unit 4 and a power supply driving module. The magnetic field generator 1 is driven by a stepping motor, loads a double-shaft rotating magnet and an additional single-shaft rotating permanent magnet 12 module, and is used to generate a composite low-frequency magnetic field signal. The controller is responsible for driving the magnet to rotate, controlling the measurement process and synchronously collecting the magnetic field sensor 2 signal. The magnetic field sensor 2 measures the three-axis magnetic field vector, and the angle encoder records the magnetic angle position information. The computing unit 4 performs real-time processing on the data, solves the target position and attitude, and outputs the six-degree-of-freedom prediction result.

[0043] The system mainly comprises the following parts: The magnetic field generator 1 is built into the base station module 6, generates a magnetic field signal with time-varying characteristics, can simulate geomagnetic disturbance and enhance the solvability of the positioning system. The magnetic field is a low-frequency composite magnetic field, which can be detected by the receiving end after being superimposed on the natural geomagnetic field.

[0044] The control unit 5 is also integrated into the base station module 6, is responsible for driving and controlling the magnetic field generator 1, coordinating the rotation rhythm of the magnet, triggering the measurement process, and transmitting data synchronously with the computing system through the interface.

[0045] The magnetic sensor is embedded inside the object to be measured 3, and is used to collect external magnetic field vector data. The sensor has the ability to measure three-axis magnetic field components and can stably operate in a mixed environment of changing magnetic field and geomagnetic field.

[0046] The object to be measured 3 is a target that needs real-time positioning, and a magnetic sensor is installed inside the object. The position and attitude of the object are described in Cartesian coordinates and Euler angles, respectively, and are denoted as ).

[0047] The changing magnetic field is dynamically generated by the magnetic field generator 1, covers a predetermined three-dimensional space area, and forms a combined field with the natural geomagnetic field, so as to enhance the positioning accuracy and spatial information recognition degree.

[0048] The computer system receives data from the magnetic sensor, communicates through the interface module, calls the internal processor to perform data analysis tasks, and runs the positioning program to model and solve the collected magnetic field data, and outputs the six-degree-of-freedom spatial information of the target object.

[0049] The base station module 6: the integrated magnetic field generator 1 and the control unit 5 are the core of the system magnetic source and control logic. Its structural design has good electromagnetic shielding performance and high frequency response characteristics.

[0050] In the actual work process, the magnetic field generator 1 generates a changing magnetic field according to the preset control law, the magnetic sensor collects the magnetic field vector coupled with the geomagnetic field in real time, and sends it to the computing system through wired or wireless mode. The latter is based on the known magnetic source motion model and sensor position model, combined with the magnetic moment direction , the revolution radius , the displacement between the sensor and the magnetic source and other parameters, the spatial position and attitude of the target object in the global coordinate system are calculated by the inversion algorithm.

[0051] The computing unit 4 includes: The magnetic field modeling module is used to build the theoretical model of the double magnetic source composite magnetic field; the magnetic field modeling module is based on the magnetic dipole theory to build the mathematical model of the double source magnetic field, and the model parameters are calibrated by experiment calibration method.

[0052] The data filtering module is used to filter out background noise and non-target frequency band magnetic signals; the data filtering module adopts a band-pass filter, the center frequency of which matches the rotation frequency of the permanent magnet, and is used to remove the geomagnetic direct current interference and high frequency noise.

[0053] The initial value inversion module is used to solve the initial estimate value of the target position based on the magnetic dipole model; The fuzzy solution elimination module is based on the residual consistency judgment strategy under the double magnetic field source, combined with the composite magnetic field characteristics of the double-axis rotating permanent magnet 11 and the single-axis rotating permanent magnet 12, the residual consistency of different solutions in the candidate solution set under the double magnetic field response is calculated, and the solutions that do not conform to the double magnetic field response coupling rule are removed. The fuzzy solution elimination module calculates the error sum of each candidate solution by constructing the residual function under the double magnetic field source, and selects the residual minimum solution as the final positioning result.

[0054] Among them, the system further introduces time sequence dynamic consistency judgment and nonlinear optimization algorithm, selects the solution with the smallest residual and the strongest time consistency in multiple magnetic field measurement sequences as the final unique positioning solution, so as to effectively avoid the multi-solution problem caused by the geometric symmetry of magnetic field.

[0055] Further including a nonlinear optimization module, using Levenberg-Marquardt algorithm to refine the six-degree-of-freedom solution of the initial value.

[0056] The positioning system supports wireless communication module, and sends the calculation result to the terminal device in real time through Wi-Fi. The overall power consumption of the system is less than 500mW, which is suitable for portable positioning equipment.

[0057] The magnetic positioning method of the application comprises the following steps: Magnetic field generation: control the synchronous operation of the biaxial rotating permanent magnet 11 and the single-axis rotating permanent magnet 12 to generate a composite time-varying magnetic field, and ensure that the rich characteristics of the spatial magnetic field vector are obtained within one magnetic field period.

[0058] Data acquisition and preprocessing: in the sampling period, the magnetic field sensor 2 synchronously acquires the magnetic field three-component data, and records the angle information of each rotating unit; the direct current component and high-frequency noise are eliminated by using a band-pass filter.

[0059] Preliminary position solution: compare the measured magnetic field data with the magnetic field model, and calculate the candidate position set of the target by using the inversion algorithm, i.e. the inverse equation based on the magnetic dipole model, and the candidate position set contains several initial estimated values.

[0060] Fuzzy solution determination and elimination: in the traditional biaxial rotating positioning, different spatial positions may produce similar magnetic field vector sequences, resulting in multiple iterative solutions (fuzzy solutions). The additional magnetic field sequence introduced by the additional single-axis rotating permanent magnet 12 is superimposed in the solution, and the matching degree of the additional magnetic field sequence is used to determine whether the solution is consistent with the double-magnetic-field joint time sequence characteristics. By comparing the residuals of the theoretical magnetic field response and the measured response of the candidate solution under the two sets of magnetic field sources, the unique solution with the smallest residual and the highest consistency is selected.

[0061] Result output and update: output the unique positioning result, and perform smoothing processing and dynamic tracking according to the time sequence correlation of continuous measurement.

[0062] The magnetic positioning system provided by the application is mainly applied to high-precision positioning scenes in a small range of three-dimensional space, and is suitable for but not limited to medical navigation, robot end tracking, special training system, etc.

[0063] The specific positioning method is as follows: Figure 1 The magnetic positioning system is taken as an example for description.

[0064] As shown in Figure 2 The magnetic field generation structure device of the application comprises: Biaxial rotating permanent magnet 11: used for realizing composite rotating motion around two perpendicular rotating axes (X-axis and Y-axis) to form a first time-varying magnetic field; Stepping motor (driving motor 14) and bearing assembly: driving the biaxial magnet to rotate, providing stable power and ensuring that the rotating frequency is controllable; Single-axis rotating permanent magnet 12: installed above or on the side of the biaxial magnet device to generate a second additional magnetic field in an independent axial rotating mode, and cooperate with the main magnetic field source to improve the uniqueness of the solution; Bevel gear drive structure: used for transmitting power between different rotating shafts to realize multi-axis linkage; Fixed connecting shaft 18: As the core structure of the rotating shaft, it connects each magnet to the motor assembly; Structural fasteners and mounting base 13: provide stable support for the device, integrate various mechanical components, and ensure system rigidity and precision.

[0065] The specific connection method includes a first bevel gear 15 provided on the mounting base 13, the output shaft of the drive motor 14 passing through the mounting base 13 and the first bevel gear 15 and extending above the first bevel gear 15, the dual-axis rotating permanent magnet 11 being connected to the second bevel gear 16 and the third bevel gear 17 respectively, the second bevel gear 16 and the third bevel gear 17 being rotatably connected to the fixed connecting shaft 18 respectively, the fixed connecting shaft 18 being connected to the output shaft in an axially perpendicular manner through a bushing, and the single-axis rotating permanent magnet 12 being connected to the top of the output shaft.

[0066] like Figure 3 As shown, the exemplary mathematical model diagram of the magnetic positioning device illustrates the geometric and motion relationships of the present invention in a space magnetic field positioning system. This system includes the following main components: Rotating permanent magnet: its magnetic moment direction is represented by It indicates that it is installed on a rotating structure, and its revolution angular velocity is... With rotational angular velocity Under the combined action of these factors, a stable space magnetic field excitation is achieved. The magnetic field generated constitutes the main excitation signal source.

[0067] Revolutionary trajectory 7: This is the path of the permanent magnet's circular motion around its central axis. Figure 3 The path is represented by a dashed line. The radius of this path is set as a known quantity. With the center of the trajectory set as the origin, a right-handed Cartesian coordinate system is established. ), used as a global reference coordinate system.

[0068] Magnetic sensor: Installed in the object under test 3, it receives the changing magnetic field emitted by the rotating magnet. The triaxial magnetic field data recorded by this sensor will serve as input for attitude and position inversion. The spatial distance between the sensor and the permanent magnet is denoted as... Its position and orientation in the global coordinate system are represented by a six-dimensional vector. ) describe.

[0069] Relationship between magnetic moment direction (m) and rotation: In addition to its revolution around the sun, the permanent magnet also rotates about its own vertical axis, the direction of which is indicated by the marked double-headed arrow, and the angular velocity is... This is used to form more complex time-varying magnetic field structures and improve the uniqueness of system solutions.

[0070] The algorithm flowchart of this invention is as follows: Figure 4As shown. The magnetic positioning method proposed in this embodiment is based on the magnetic field signal constructed by the dual-axis rotating magnet 11. By analyzing the magnetic field observation data at multiple time points, the spatial three-dimensional position and attitude parameters of the target sensor are deduced.

[0071] Exemplary mathematical models of magnetic positioning systems are as follows: Figure 3 As shown, it includes a rotating magnet located on a planar circular track. and the auxiliary magnet located at the center of the rotation axis. Its magnetic moment direction can rotate synchronously or asynchronously. The sensor is placed at any point in the far-field space. The signal is calculated after sensing the superimposed magnetic field of the two magnets.

[0072] The vectors from the two magnets to the sensor are respectively: and Due to magnet Fixed at the axial height ,according to Figure 3 The relationship between the right triangles can be obtained as follows: and ,in .

[0073] I. Magnetic field analytical modeling.

[0074] Assume a magnet , with vector The included angles are respectively Then the magnitude of the magnetic field strength sensed by the sensor is: (1) In the next moment The two magnets rotated respectively The corresponding magnetic field modulus is: (2) To eliminate distance The influence of angle calculation is addressed by introducing a geometric ratio parameter: (3) After substituting, the rewritten equations (2) and (3) are as follows: (4) (5) To eliminate the scaling factor Construct a normalized angle function: (6) This function depends only on the angle variable. Rotation angle Magnetic moment ratio Height ratio parameters Numerical solution The unique solution as the initial value of positioning. The ratio of the model's predicted value to the measured value at a certain angle θ is 1, which is the angle we are looking for .

[0075] Two-axis and three-axis component analytical expansion: According to the expansion form of the magnetic dipole, the magnetic field components satisfy the following formula: (7) (8) (9) Where: is an auxiliary variable to simplify the calculation expression.

[0076] Use equations (7)~(9) to inversely solve the initial estimate value as the starting point for subsequent optimization.

[0077] Three, environmental interference and nonlinear optimization.

[0078] Actual measurement value contains geomagnetic interference , sensor rotation disturbance Therefore: (10) In order to remove non-target frequency band interference signals, the system implements band-pass filtering on the original data, with the center frequency matching the magnet rotation frequency to retain the main signal. After filtering, use the initial value as the starting point to construct the error function: (11) Where is the six-degree-of-freedom pose parameter to be estimated. After minimizing the objective function, the estimated solution is output.

[0079] Four, fuzzy solution removal and unique solution selection.

[0080] Since the magnetic field may have mirror ambiguous solutions, the system introduces a double-field source co-time comparison mechanism. Calculate the theoretical response of the candidate solution under the field of the double-axis magnet and the additional single-axis magnet, and compare their residuals: (12) Select the minimum one as the final solution to ensure the uniqueness of positioning.

[0081] In summary, the magnetic positioning system provided in the application constructs a composite magnetic signal based on a double-axis plus single-axis rotating magnetic field, combines analytical modeling and a nonlinear optimization algorithm, and realizes high-precision positioning and dynamic tracking of a space target. The system has a simple and compact structure and efficient operation, and avoids the problems of high-frequency interference and low-frequency algorithm solving difficulty of traditional electromagnetic positioning. By adding a single-axis rotating permanent magnet to the revolution axis to change the timing characteristics of the magnetic field, the differences in the magnetic field vector sequences corresponding to different spatial positions are significantly different, and the probability of multiple solutions is reduced. Through joint matching residual judgment of the double magnetic field sources, the fuzzy solution is quickly eliminated, and the uniqueness of positioning and the calculation efficiency are improved. The system as a whole is compact and low-power, and is suitable for virtual / augmented reality, medical navigation, robot positioning and other high-precision scenarios.

[0082] It should be noted that the relative terms such as first and second, and the like are used herein only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between such entities or operations. Moreover, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a list of elements does not only include those elements, but also includes other elements not expressly listed, or other elements inherent in such process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0083] From the above description of the embodiments, those skilled in the art can clearly understand that the application can be implemented by means of software plus the necessary general hardware platform. Based on such understanding, the technical solutions of the application can be embodied in the form of a software product, which can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for making a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in the various embodiments or some parts of the embodiments.

[0084] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0085] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A magnetic positioning system, characterized by The application relates to a magnetic field positioning system, which comprises the following parts: a magnetic field generator, a magnetic field sensor and a calculation unit. The magnetic field generator comprises a double-axis rotating permanent magnet and a single-axis rotating permanent magnet, the double-axis rotating permanent magnet is configured to rotate around two mutually perpendicular and non-coplanar axes to generate a spatially non-uniformly changing time-varying magnetic field; the rotating axis of the single-axis rotating permanent magnet is coaxial with or coupled with the rotating structure of the double-axis rotating permanent magnet, and independently rotates around its own axis to generate an additional magnetic field which is used to superimpose with the time-varying magnetic field to destroy the symmetry of the magnetic field distribution and obtain a composite time-varying magnetic field. The magnetic field sensor is arranged in an object to be measured and is used to measure three-dimensional magnetic field component data at a target spatial position. The calculation unit is used to execute a positioning method, which comprises the following steps: after the double-axis rotating permanent magnet and the single-axis rotating permanent magnet are synchronously operated to generate the composite time-varying magnetic field, magnetic field three-component data synchronously collected by the magnetic field sensor in a sampling period is obtained, and angle information of the double-axis rotating permanent magnet and the single-axis rotating permanent magnet is obtained; a candidate position set of the target is calculated based on a magnetic dipole model inverse equation by using the magnetic field three-component data and the angle information; a matching degree judgment of an additional magnetic field sequence introduced by the single-axis rotating permanent magnet is superimposed in the calculation so as to eliminate solutions which do not conform to the double-magnetic-field joint time sequence characteristics; a unique solution with the minimum residual error and the highest consistency is selected as a unique positioning result by comparing residual errors of theoretical magnetic field responses and measured responses of a plurality of initial estimated values in the candidate position set under two sets of magnetic field sources through a residual function; The unique positioning result is output, and smoothing processing and dynamic tracking are performed according to time sequence correlation of continuous measurement. The residual function is represented by the following formula: The initial estimated value is obtained by inverse solution of the following formula: The unique solution with the minimum residual error and the highest consistency is selected as the unique positioning result by using time sequence dynamic consistency judgment and a nonlinear optimization algorithm.

2. The magnetic positioning system of claim 1, wherein, The rotating axis of the single-axis rotating permanent magnet is coincident with one of the rotating axes of the double-axis rotating permanent magnet. In the formula: denotes the residual comparison value, In denotes the magnetic field vector, the superscript denotes the corresponding magnetic field source, the subscript denotes the theoretical value, denotes the measured value.

3. The magnetic positioning system of claim 1, wherein, The double-axis rotating permanent magnet and the single-axis rotating permanent magnet are connected with angle encoders, and the angle encoders are used to obtain the angle information. wherein: , , represent the three axial components of the magnetic field, represent the vacuum permeability, , , represent the vector from the biaxial rotating permanent magnet to the magnetic field sensor, represent the vector from the uniaxial rotating permanent magnet to the magnetic field sensor, represent auxiliary variables, represent the height of the uniaxial rotating permanent magnet above the axial direction.

4. The magnetic positioning system of claim 3, wherein, A control unit is further arranged, which is used to drive the rotation of the permanent magnet and synchronously collect the magnetic field and the angle information; time synchronization is realized between the control unit and the magnetic field sensor and the angle encoders in a time stamp synchronous mode.

5. The magnetic positioning system of claim 4, wherein, The non-linear optimization algorithm comprises An algorithm, the The algorithm is used to refine the initial estimate for a six degree of freedom solution.

6. The magnetic positioning system of claim 1, wherein, The magnetic field generator further comprises a mounting base and a driving motor, the mounting base is provided with a first bevel gear, an output shaft of the driving motor extends to the upper side of the first bevel gear through the mounting base and the first bevel gear, the double-axis rotating permanent magnet is connected with a second bevel gear and a third bevel gear respectively, the second bevel gear and the third bevel gear are rotatably connected with a fixed connecting shaft respectively, the fixed connecting shaft is connected with the output shaft in an axial vertical mode through a shaft sleeve, and the single-axis rotating permanent magnet is connected with the top of the output shaft.

7. The magnetic positioning system of claim 1, wherein, ​ 8. The magnetic positioning system of claim 6, wherein, ​ 9. The magnetic positioning system of claim 1, wherein, ​

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