Method for magnetic field quality assessment and frequency hopping control strategy for electromagnetic positioning tracking

Abstract

The present application relates to the technical field of electromagnetic positioning tracking, and especially relates to a magnetic field quality evaluation method and frequency hopping control strategy for electromagnetic positioning tracking. The magnetic field quality evaluation method can effectively evaluate the magnetic field quality of the frequency division control or time division control electromagnetic positioning tracking system, and has important value for optimizing the positioning tracking accuracy of the system and evaluating the effectiveness of the positioning result. The magnetic field frequency hopping control strategy proposed by the method can effectively avoid the situation that the magnetic field frequency of the electromagnetic positioning tracking system is close to the frequency of the interference magnetic field existing in the environment, reduce the influence of the interference magnetic field existing in the environment on the positioning tracking accuracy, and enable the electromagnetic positioning tracking system to self-learn a best frequency list order suitable for the current environment, so that the subsequent frequency hopping control module can be accelerated to adapt to the speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electromagnetic positioning tracking technology, in particular to a magnetic field quality evaluation method and frequency hopping control strategy for electromagnetic positioning tracking. BACKGROUND

[0002] Electromagnetic positioning tracking technology can realize real-time positioning and tracking of the spatial position and attitude of a positioning target in a meter-level range, and its positioning accuracy can reach millimeter to sub-millimeter level, which has important application prospects in the field of minimally invasive intervention surgery. Compared with optical positioning tracking technology, electromagnetic positioning tracking can effectively avoid the problem of target loss of optical positioning tracking system caused by optical occlusion, but there is a deficiency that the emitted magnetic field of the electromagnetic positioning tracking technology is easily affected by environmental factors, resulting in a decrease in positioning accuracy. Therefore, it is particularly important to accurately evaluate the magnetic field quality of the electromagnetic positioning tracking system within the effective range. SUMMARY

[0003] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the description and the drawings.

[0004] The present application aims to overcome the above-mentioned deficiencies, and provides a magnetic field quality evaluation method and frequency hopping control strategy for electromagnetic positioning tracking. The proposed magnetic field quality evaluation method can effectively evaluate the magnetic field quality of a frequency division control or time division control electromagnetic positioning tracking system, which has important value for optimizing the positioning tracking accuracy of the system and evaluating the effectiveness of the positioning result. The magnetic field frequency hopping control strategy proposed by the method can effectively avoid the situation that the magnetic field frequency of the electromagnetic positioning tracking system is close to the frequency of the interference magnetic field existing in the environment, thereby reducing the influence of the interference magnetic field existing in the environment on the positioning tracking accuracy. At the same time, the electromagnetic positioning tracking system can self-learn a best frequency list order suitable for the current environment, and the subsequent frequency hopping control module can be accelerated to adapt to the speed according to the order of the list.

[0005] The present application provides a magnetic field quality evaluation method and frequency hopping control strategy for electromagnetic positioning tracking, comprising:

[0006] S1, establishing an electromagnetic positioning tracking system, the electromagnetic positioning tracking system comprising a magnetic field generation control module, a transmitting coil, a receiving coil, a receiving signal processing module, a pose solving module, and a frequency division quality evaluation module and a time division quality evaluation module selected and set according to the multiplexing mode of the magnetic field generation control module;

[0007] The magnetic field generation control module generates an alternating current signal of a specific frequency and amplitude, the transmitting coil converts the alternating current signal into an alternating magnetic field and realizes transmission in a specific environment, the receiving coil converts the magnetic field signal in the specific environment into an electric signal, and the spatial position and attitude of the receiving coil relative to the transmitting coil are calculated by the receiving signal processing module and the pose solving module, so as to realize positioning and tracking of the receiving coil;

[0008] S2, for the frequency division multiplexing magnetic field generation control module, the receiving coil is at least two single-axis receiving coils, the output end of the pose solving module is connected with the frequency division quality evaluation module, an effective value reflecting the magnetic field quality is obtained through the pose relationship between the at least two single-axis receiving coils, and the effective value is input into the frequency division quality evaluation module, so as to judge the magnetic field quality;

[0009] S3, for the time division multiplexing magnetic field generation control module, when the magnetic field generation control module is in an idle state, no alternating current signal is sent, at this time, the magnetic field signal received by the receiving coil is only affected by the environment, the receiving signal processing module processes the magnetic field signal received by the receiving coil, obtains a specific frequency component existing in the environmental magnetic field, and inputs the specific frequency component into the time division quality evaluation module, so as to judge the magnetic field quality;

[0010] S4, the frequency division quality evaluation module and the time division quality evaluation module are both provided with a magnetic field quality evaluation standard, the magnetic field quality evaluation standard divides the magnetic field quality into multiple levels, the electromagnetic positioning and tracking system is also provided with a frequency hopping control module, the output ends of the frequency division quality evaluation module and the time division quality evaluation module are connected with the frequency hopping control module, the frequency hopping control module is provided with a frequency hopping control strategy, the available frequencies are switched, and a frequency meeting the strategy is searched.

[0011] In some embodiments, in the S2 step, the specific steps of judging the magnetic field quality through the pose relationship between the single-axis coils are as follows:

[0012] S21, the positions and attitudes of the two single-axis coils are received;

[0013] S22, for the receiving coil used, there is a physical included angle between the two single-axis coil axes which is determined and known to be fixed, and is denoted as θ;

[0014] S23, according to the position and attitude solving results of the two single-axis coils, the physical included angle between the two single-axis coils and the horizontal plane is calculated, and the included angle difference between the two single-axis coils is denoted as α;

[0015] S24, the offset Δ between the physical included angle of the two single-axis coils and the calculated value of the physical included angle is calculated, Δ = | α- θ |;

[0016] S25. Input the offset Δ into the frequency division quality assessment module. The frequency division quality assessment module will correspond the offset Δ with the magnetic field quality and divide it into multiple levels. The level range in which the offset Δ falls corresponds to the level of magnetic field quality of the environment to which the two single-axis coils belong.

[0017] In some embodiments, in step S3, the specific frequency component after signal processing is a specific value N, where N is a voltage signal. This voltage signal is input to the time-division quality assessment module, which correlates the voltage signal N with the magnetic field quality and divides it into multiple levels. The level range in which the voltage signal N falls corresponds to the level of the magnetic field quality of the environment within that time interval.

[0018] In some embodiments, both the frequency division quality assessment module and the time division quality assessment module are provided with three or more magnetic field quality assessment level ranges, and the specific division of the level ranges is set manually.

[0019] In some embodiments, in step S4, after the frequency division quality assessment module and the time division quality assessment module assess the magnetic field quality, they output the assessment level to the frequency hopping control module. If the magnetic field quality of the current environment is assessed as too low, a frequency is selected from the available frequency list of the system from top to bottom, and the magnetic field generation control module is controlled to transmit different frequencies to reassess the magnetic field quality at that frequency.

[0020] In some embodiments, if the magnetic field quality of the current environment is assessed to be suitable, the frequency value emitted by the current magnetic field generation control module is recorded in the system's available frequency list, and the frequency list is updated.

[0021] In some embodiments, if no suitable frequency is found for the magnetic field environment after selecting a frequency from top to bottom using frequency hopping, a prompt indicating that no suitable frequency is available is output.

[0022] By adopting the above technical solution, the beneficial effects of the present invention are:

[0023] The magnetic field quality assessment method proposed in this invention can effectively evaluate the magnetic field quality of frequency division control or time division control electromagnetic positioning and tracking systems, which is of great value for optimizing the positioning and tracking accuracy of the system and evaluating the effectiveness of the positioning results.

[0024] The magnetic field frequency hopping control strategy proposed by this method can effectively avoid the magnetic field frequency of the electromagnetic positioning and tracking system being close to the frequency of the interfering magnetic field in the environment, thereby reducing the impact of the interfering magnetic field in the environment on the positioning and tracking accuracy.

[0025] The magnetic field frequency hopping control strategy proposed by this method allows the electromagnetic positioning and tracking system to learn a list of optimal frequencies suitable for the current environment. Subsequently, the adaptation speed of the frequency hopping control module can be accelerated by following the order of this list.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure.

[0027] Undoubtedly, such and other objects of the present invention will become more apparent after the following detailed description of the preferred embodiments, which are illustrated in various accompanying drawings and figures.

[0028] To make the above and other objects, features and advantages of the present invention more apparent and understandable, one or more preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0030] In the accompanying drawings, the same parts use the same reference numerals, and the drawings are schematic and not necessarily drawn to actual scale.

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on such drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of the electromagnetic positioning and tracking system in some embodiments of the present invention;

[0033] Figure 2 This is a schematic diagram illustrating the specific process of frequency division quality assessment in some embodiments of the present invention;

[0034] Figure 3 This is a schematic diagram illustrating the specific calculation process of frequency division quality assessment in some embodiments of the present invention;

[0035] Figure 4 This is a schematic diagram illustrating the specific process of time-division quality assessment in some embodiments of the present invention;

[0036] Figure 5 This is a schematic diagram illustrating the specific calculation process of time-division quality assessment in some embodiments of the present invention;

[0037] Figure 6This is a schematic diagram illustrating the specific process of frequency hopping control in some embodiments of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] Furthermore, in the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" 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 invention 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 invention.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral unit; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. However, specifying a direct connection indicates that the two main bodies are not connected through a transitional structure, but rather formed as a whole through a connecting structure. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. 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.

[0042] Reference Figures 1-6 , Figure 1 This is a schematic diagram of the overall structure of the electromagnetic positioning and tracking system in some embodiments of the present invention; Figure 2 This is a schematic diagram illustrating the specific process of frequency division quality assessment in some embodiments of the present invention;Figure 3 This is a schematic diagram illustrating the specific calculation process of frequency division quality assessment in some embodiments of the present invention; Figure 4 This is a schematic diagram illustrating the specific process of time-division quality assessment in some embodiments of the present invention; Figure 5 This is a schematic diagram illustrating the specific calculation process of time-division quality assessment in some embodiments of the present invention; Figure 6 This is a schematic diagram illustrating the specific process of frequency hopping control in some embodiments of the present invention.

[0043] According to some embodiments of the present invention, the present invention provides a magnetic field quality assessment method and a frequency hopping control strategy for electromagnetic positioning and tracking, including:

[0044] S1. Establish an electromagnetic positioning and tracking system, which includes a magnetic field generation and control module, a transmitting coil, a receiving coil, a receiving signal processing module, a pose calculation module, and a frequency division quality assessment module and a time division quality assessment module selected according to the different multiplexing methods of the magnetic field generation and control module.

[0045] like Figure 1 As shown, the magnetic field generation control module generates an alternating current signal with a specific frequency and amplitude. The transmitting coil converts the alternating current signal into an alternating magnetic field and transmits it within a specific environment. The receiving coil converts the magnetic field signal within the specific environment into an electrical signal. The receiving signal processing module and the pose calculation module calculate the spatial position and attitude of the receiving coil relative to the transmitting coil, thereby achieving positioning and tracking of the receiving coil.

[0046] S2. For the frequency division multiplexing magnetic field generation control module, the receiving coil is at least two single-axis receiving coils. The output end of the pose calculation module is connected to the frequency division quality assessment module. An effective value reflecting the magnetic field quality is obtained through the pose relationship between at least two single-axis receiving coils. The effective value is input into the frequency division quality assessment module to judge the magnetic field quality.

[0047] like Figures 2-3 As shown, the specific steps for judging the magnetic field quality through the pose relationship between single-axis coils are as follows:

[0048] S21. Receive the position and orientation of the two single-axis coils;

[0049] S22. For the receiving coil used, there is a definite and known fixed physical angle between the axes of two single-axis coils, denoted as θ.

[0050] S23. Based on the position and attitude calculation results of the two single-axis coils, calculate the physical angle between the two single-axis coils and the horizontal plane, and denot the angle difference between the two single-axis coils as α.

[0051] S24. Find the offset Δ between the physical angle between the two single-axis coils and the calculated value of the physical angle, where Δ = |α - θ;

[0052] S25. Input the offset Δ into the frequency division quality assessment module. The frequency division quality assessment module will correspond the offset Δ with the magnetic field quality and divide it into multiple levels. The level range in which the offset Δ falls corresponds to the level of magnetic field quality of the environment to which the two single-axis coils belong.

[0053] S3. For the time-division multiplexing magnetic field generation control module, when the magnetic field generation control module is in an idle state, it does not send an alternating current signal. At this time, the magnetic field signal received by the receiving coil is only affected by the environment. The receiving signal processing module processes the magnetic field signal received by the receiving coil to obtain the specific frequency component present in the ambient magnetic field. The specific frequency component is then input to the time-division quality assessment module to judge the magnetic field quality.

[0054] like Figures 4-5 As shown, the specific frequency component after signal processing is a specific value N, which is a voltage signal. This voltage signal is input to the time-division quality assessment module, which correlates the voltage signal N with the magnetic field quality and divides it into multiple levels. The level range in which the voltage signal N falls corresponds to the quality of the magnetic field of the environment within that time interval.

[0055] S4. Both the frequency division quality assessment module and the time division quality assessment module are equipped with magnetic field quality assessment standards. These standards divide magnetic field quality into multiple levels. The electromagnetic positioning and tracking system is also equipped with a frequency hopping control module. The outputs of both the frequency division quality assessment module and the time division quality assessment module are connected to the frequency hopping control module. The frequency hopping control module is equipped with a frequency hopping control strategy to switch available frequencies and find frequencies that meet the strategy.

[0056] Both the frequency division quality assessment module and the time division quality assessment module have three or more magnetic field quality assessment level ranges, and the specific division of these level ranges is set manually.

[0057] like Figure 6 As shown, after the frequency division quality assessment module and the time division quality assessment module assess the magnetic field quality, they output the assessment level to the frequency hopping control module. If the magnetic field quality of the current environment is assessed as too low, the frequency is selected from the top to the bottom of the available frequency list of the system, and the magnetic field generation control module is controlled to transmit different frequencies to reassess the magnetic field quality at that frequency.

[0058] If the current magnetic field quality is deemed suitable, the frequency value emitted by the current magnetic field generation control module is recorded in the system's available frequency list, and the frequency list is updated.

[0059] If no suitable frequency is found for the magnetic field environment after selecting a frequency from top to bottom using frequency hopping, a message indicating that no suitable frequency is available will be output.

[0060] It should be understood that the embodiments disclosed herein are not limited to the specific processing steps or materials disclosed herein, but should be extended to equivalent substitutions of such features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0061] The term "embodiment" in this specification refers to a specific feature or characteristic described in connection with an embodiment that is included in at least one embodiment of the invention. Therefore, phrases or "embodiments" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0062] Furthermore, the described features or characteristics can be incorporated into one or more embodiments in any other suitable manner. In the above description, specific details, such as thickness, quantity, etc., are provided to provide a comprehensive understanding of embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented without the aforementioned specific details or may be implemented using other methods, components, materials, etc.

Claims

1. A magnetic field quality assessment method and frequency hopping control strategy for electromagnetic positioning and tracking, characterized in that, include S1. Establish an electromagnetic positioning and tracking system, which includes a magnetic field generation and control module, a transmitting coil, a receiving coil, a receiving signal processing module, a pose calculation module, and a frequency division quality assessment module and a time division quality assessment module selected according to the different multiplexing methods of the magnetic field generation and control module. The magnetic field generation control module generates an alternating current signal with a specific frequency and amplitude. The transmitting coil converts the alternating current signal into an alternating magnetic field and transmits it within a specific environment. The receiving coil converts the magnetic field signal within the specific environment into an electrical signal. The receiving signal processing module and the pose calculation module calculate the spatial position and attitude of the receiving coil relative to the transmitting coil, thereby achieving positioning and tracking of the receiving coil. S2. For the frequency division multiplexing magnetic field generation control module, the receiving coil is at least two single-axis receiving coils. The output end of the pose calculation module is connected to the frequency division quality assessment module. An effective value reflecting the magnetic field quality is obtained through the pose relationship between at least two single-axis receiving coils. The effective value is input into the frequency division quality assessment module to judge the magnetic field quality. S3. For the time-division multiplexing magnetic field generation control module, when the magnetic field generation control module is in an idle state, it does not send an alternating current signal. At this time, the magnetic field signal received by the receiving coil is only affected by the environment. The receiving signal processing module processes the magnetic field signal received by the receiving coil to obtain the specific frequency component present in the ambient magnetic field. The specific frequency component is then input to the time-division quality assessment module to judge the magnetic field quality. S4. Both the frequency division quality assessment module and the time division quality assessment module are equipped with magnetic field quality assessment standards. These standards divide magnetic field quality into multiple levels. The electromagnetic positioning and tracking system is also equipped with a frequency hopping control module. The outputs of both the frequency division quality assessment module and the time division quality assessment module are connected to the frequency hopping control module. The frequency hopping control module is equipped with a frequency hopping control strategy to switch available frequencies and find frequencies that meet the strategy. In step S2, the specific steps for determining the magnetic field quality based on the pose relationship between the single-axis coils are as follows: S21. Receive the position and orientation of the two single-axis coils; S22. For the receiving coil used, there is a definite and known fixed physical angle between the axes of two single-axis coils, denoted as θ. S23. Based on the position and attitude calculation results of the two single-axis coils, calculate the physical angle between the two single-axis coils and the horizontal plane, and denot the angle difference between the two single-axis coils as α. S24. Find the offset Δ between the physical angle between the two single-axis coils and the calculated value of the physical angle, where Δ = |α - θ|. S25. Input the offset Δ into the frequency division quality assessment module. The frequency division quality assessment module will correspond the offset Δ with the magnetic field quality and divide it into multiple levels. The level range in which the offset Δ falls corresponds to the level of magnetic field quality of the environment to which the two single-axis coils belong. In step S3, the specific frequency component after signal processing is a specific value N, which is a voltage signal. This voltage signal is input to the time-division quality assessment module. The time-division quality assessment module corresponds the voltage signal N to the magnetic field quality and divides it into multiple levels. The level range in which the voltage signal N falls corresponds to the level of the magnetic field quality of the environment within the time interval. In step S4, after the frequency division quality assessment module and the time division quality assessment module assess the magnetic field quality, they output the assessment level to the frequency hopping control module. If the magnetic field quality of the current environment is assessed as too low, a frequency is selected from the available frequency list of the system from top to bottom, and the magnetic field generation control module is controlled to transmit different frequencies to reassess the magnetic field quality at that frequency. If the magnetic field quality of the current environment is assessed as appropriate, the frequency value transmitted by the current magnetic field generation control module is recorded in the available frequency list of the system, and the frequency list is updated.

2. The magnetic field quality assessment method and frequency hopping control strategy for electromagnetic positioning and tracking according to claim 1, characterized in that, Both the frequency division quality assessment module and the time division quality assessment module have three or more magnetic field quality assessment level ranges, and the specific division of these level ranges is set manually.

3. The magnetic field quality assessment method and frequency hopping control strategy for electromagnetic positioning and tracking according to claim 1, characterized in that, If no suitable frequency is found for the magnetic field environment after selecting a frequency from top to bottom using frequency hopping, a message indicating that no suitable frequency is available will be output.

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