CN-121383995-B - Magnetic positioning system

CN121383995BCN 121383995 BCN121383995 BCN 121383995BCN-121383995-B

Abstract

The invention discloses a magnetic positioning system, which relates to the technical field of position detection and space positioning, and is used for constructing a composite magnetic signal based on a double-shaft and single-shaft rotating magnetic field and realizing high-precision positioning and dynamic tracking of a space target by combining analytic modeling and a nonlinear optimization algorithm. The system has simple and compact structure and high operation efficiency, and solves the difficult problem that the traditional electromagnetic positioning high-frequency interference and low-frequency algorithm are difficult to solve. The magnetic field time sequence characteristics are changed by adding the single-axis rotating permanent magnet on the revolution axis, so that the magnetic field vector sequences corresponding to different space positions are obviously differentiated, and the probability of occurrence of multiple solutions is reduced. And the quick elimination of the fuzzy solution is realized by judging the combined matching residual errors of the double magnetic field sources, and the positioning uniqueness and the calculation efficiency are improved. The system is compact in whole and low in power consumption, and is suitable for scenes requiring high precision, such as virtual/augmented reality, medical navigation, robot positioning and the like.

Inventors

YANG FENG
LI JINZE
HUANG YIFAN

Assignees

艾瑞迈迪医疗科技（北京）有限公司

Dates

Publication Date: 20260512
Application Date: 20251029

Claims (7)

1. A magnetic positioning system, comprising: The magnetic field generator comprises a double-shaft rotary permanent magnet and a single-shaft rotary permanent magnet, wherein the double-shaft rotary permanent magnet is configured to rotate around two mutually perpendicular and non-coplanar axes to generate a time-varying magnetic field with a non-uniform space change; The magnetic field sensor is arranged in the object to be measured and is used for measuring three-dimensional magnetic field component data at the position of the target space; A computing unit for performing a positioning method, the positioning method comprising: The magnetic field three-component data synchronously collected by the magnetic field sensor in a sampling period are obtained, and angle information of the biaxial rotating permanent magnet and the uniaxial rotating permanent magnet is obtained; Calculating a candidate position set of the target based on an inverse solution equation of a magnetic dipole model by utilizing the magnetic field three-component data and the angle information; the method comprises the steps of utilizing an additional magnetic field sequence introduced by a single-axis rotating permanent magnet, superposing matching degree judgment of the additional magnetic field sequence in resolving so as to reject solutions which do not accord with double magnetic field joint time sequence characteristics, comparing theoretical magnetic field response and actual measurement response residual errors of a plurality of initial estimated values in a candidate position set under two sets of magnetic field sources through residual error functions, and selecting a unique solution with the minimum residual error and highest consistency as a unique positioning result; outputting the unique positioning result, and performing smoothing and dynamic tracking according to the continuous measurement time sequence correlation; The magnetic field generator further comprises a mounting base and a driving motor, a first bevel gear is arranged on the mounting base, an output shaft of the driving motor penetrates through the mounting base and the first bevel gear to extend to the upper portion of the first bevel gear, the double-shaft 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 connected with a fixed connecting shaft in a rotatable mode respectively, the fixed connecting shaft is connected with the output shaft in an axial perpendicular mode through a shaft sleeve, and the single-shaft rotating permanent magnet is connected with the top of the output shaft.
2. The magnetic positioning system of claim 1, wherein the residual function is represented by: wherein: Representing the value of the residual comparison, In (a) Representing magnetic field vectors, superscripts representing corresponding magnetic field sources, subscripts The value of the theoretical value is represented by, Indicating the measured value.
3. The magnetic positioning system of claim 1, wherein the initial estimate is obtained by an inverse solution of: wherein: 、、 respectively represent the triaxial components of the magnetic field, Indicating the magnetic permeability of the vacuum, , , Representing the vector of the bi-axially rotating permanent magnet to the magnetic field sensor, Representing the vector of the uniaxially rotating permanent magnet to the magnetic field sensor, Represents the auxiliary variable(s), Representing the height of the single axis rotating permanent magnet axially above.
4. A magnetic positioning system according to claim 3, wherein a unique solution with minimum residual and highest consistency is selected as the unique positioning result by using a time series dynamic consistency determination and a nonlinear optimization algorithm.
5. The magnetic positioning system of claim 4, wherein the nonlinear optimization algorithm comprises An algorithm of the following An algorithm is used to refine the initial estimate with a six degree of freedom solution.
6. The magnetic positioning system of claim 1, wherein the biaxial rotating permanent magnet and the uniaxial rotating permanent magnet are each connected with an angle encoder for acquiring the angle information.
7. The magnetic positioning system of claim 6, further comprising a control unit for driving the permanent magnet to rotate and synchronously collecting magnetic field and angle information, wherein the control unit is time synchronized with the magnetic field sensor and the angle encoder by time stamp synchronization.

Description

Magnetic positioning system Technical Field The invention relates to the technical field of position detection and space positioning, in particular to a magnetic positioning system based on a rotary permanent magnet. Background The position detection and space positioning technology is widely applied to the fields of virtual reality, augmented reality, robot navigation, medical operation navigation, precise assembly, motion capture and the like. The existing common methods comprise optical positioning, inertial measurement positioning, ultrasonic positioning, magnetic field positioning and the like. The method has the advantages of high optical positioning accuracy, easy limitation by shielding and illumination conditions, no need of external signals for inertial measurement, error accumulation, low ultrasonic positioning cost, simple realization and larger influence by environmental noise and medium change. The magnetic field positioning technology utilizes the characteristics that a magnetic field can penetrate through nonmetallic materials and is not influenced by shielding, and can work stably in complex environments and closed spaces. Magnetic positioning systems based on rotating permanent magnets that generate time-varying magnetic fields are of interest because of their stable magnetic field sources, low power consumption, and compact structure. The common design is that the permanent magnet rotates around two intersecting rotation axes simultaneously, a time-varying magnetic field distribution is formed in space, and the sensor can calculate the position through model inversion after measuring three components of the magnetic field. In such a biaxial rotating magnetic field system, the eccentric arrangement of the permanent magnets may break the magnetic field symmetry, thereby enabling a unique three-dimensional position solution within a certain range. However, in the magnetic field positioning system in the prior art, the degree of distinction of magnetic field signals generated by different spatial positions is not high, so that the positioning accuracy is affected. Disclosure of Invention In view of the above, the present invention provides a magnetic positioning system for overcoming or at least partially solving the above-mentioned problems. The system utilizes the time-varying magnetic field generated by the permanent magnet under the rotation of multiple degrees of freedom to realize the high-precision positioning of the target sensor in the space. The invention provides the following scheme: A magnetic positioning system, comprising: A magnetic field generator comprising a bi-axial rotating permanent magnet configured to be rotatable about two mutually perpendicular and non-coplanar axes to generate a spatially non-uniformly varying time-varying magnetic field, and a uni-axial rotating permanent magnet; the rotation axis of the single-axis rotary permanent magnet is configured to be coaxial or coupled with a certain axis of the double-axis rotary permanent magnet rotation structure, and independently rotates around the own axis to generate an additional magnetic field, wherein the additional magnetic field is used for being overlapped with the time-varying magnetic field to break the symmetry of magnetic field distribution and obtain a composite time-varying magnetic field; The magnetic field sensor is arranged in the object to be measured and is used for measuring three-dimensional magnetic field component data at the position of the target space; A computing unit for performing a positioning method, the positioning method comprising: The magnetic field three-component data synchronously collected by the magnetic field sensor in a sampling period are obtained, and angle information of the biaxial rotating permanent magnet and the uniaxial rotating permanent magnet is obtained; Calculating a candidate position set of the target based on an inverse solution equation of a magnetic dipole model by utilizing the magnetic field three-component data and the angle information; the method comprises the steps of utilizing an additional magnetic field sequence introduced by a single-axis rotating permanent magnet, superposing matching degree judgment of the additional magnetic field sequence in resolving so as to reject solutions which do not accord with double magnetic field joint time sequence characteristics, comparing theoretical magnetic field response and actual measurement response residual errors of a plurality of initial estimated values in a candidate position set under two sets of magnetic field sources through residual error functions, and selecting a unique solution with the minimum residual error and highest consistency as a unique positioning result; And outputting the unique positioning result, and performing smoothing and dynamic tracking according to the time sequence correlation of continuous measurement. Preferably, the residual function is represented by the following formula: