Unmanned aerial vehicle rotor power supply line magnetic interference compensation method based on wire space modeling

Abstract

The invention discloses an unmanned aerial vehicle rotor power supply line magnetic interference compensation method based on wire space modeling. The method comprises the following steps: constructing a space three-dimensional model; constructing a compensation model composed of a plurality of power wires, and simulating the geometric characteristics and current distribution of the cross sections of the power wires through the compensation model; a non-uniform current weight is distributed to each power wire; calculating a total compensation magnetic field generated by the compensation model at the magnetic sensor based on the Biot-Savart law and the current weight by adopting a self-adaptive integration method, and calculating an error correction factor based on the total compensation magnetic field; calculating a corrected interference magnetic field based on the error correction factor and the real-time interference magnetic field; and removing the corrected interference magnetic field from the original aeromagnetic three-component data by using a difference method to obtain interference-eliminated aeromagnetic three-component data. The method can solve the problem that the precision of aeromagnetic three-component data of the unmanned aerial vehicle is insufficient due to the fact that dynamic magnetic field interference which is related to current in real time and is tightly coupled with a geometric structure cannot be accurately compensated in the prior art.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic data processing technology for unmanned aerial vehicles (UAVs), and more specifically to a method for compensating for magnetic interference in the power supply lines of UAV rotors based on conductor spatial modeling. Background Technology

[0002] Multirotor drones operate in complex environments, requiring the use of three-way magnetic sensors to detect the three components of the Earth's magnetic field. However, the multirotor drone itself is a major source of magnetic interference. Among these, the high-current power cables running inside the rotor arms to drive the brushless motors are one of the largest sources of dynamic interference.

[0003] When the motor operates, large currents (up to tens of amperes) flow through these conductors. According to the Biot-Savart law, this current generates a magnetic field in the space around the conductor that is proportional to the current intensity. This additional magnetic field superimposes on the Earth's magnetic field vector, severely contaminating the raw aeromagnetic three-component data measured by the magnetic sensors. This interference is dynamic, and its intensity and direction change in real time with the magnitude of the current in the power conductors and the drone's attitude.

[0004] Modeling is one of the commonly used methods for interference compensation. However, existing models usually treat the conductor as an infinitely long straight conductor or a single line segment. These models cannot accurately compensate for dynamic magnetic field interference that is related to the current in real time and is tightly coupled with the geometry, resulting in insufficient accuracy of the UAV aeromagnetic three-component data. Summary of the Invention

[0005] In view of this, the present invention provides a magnetic interference compensation method for UAV rotor power supply lines based on conductor space modeling, in order to solve the technical problem that the existing technology cannot accurately compensate for dynamic magnetic field interference that is related to the current in real time and is closely coupled with the geometric structure, resulting in insufficient accuracy of UAV aeromagnetic three-component data.

[0006] A method for compensating for magnetic interference in UAV rotor power supply lines based on conductor spatial modeling includes: Step S1: Obtain the three-dimensional spatial path information and physical parameter information of the power wire carrying current on the rotor arm of the UAV, as well as the installation position information of the magnetic sensor on the UAV, so as to construct a three-dimensional spatial model. Step S2: Based on the three-dimensional spatial path information and physical parameter information of the power conductor, a compensation model composed of multiple power conductors is constructed. The compensation model is used to simulate the cross-sectional geometric features and current distribution of the power conductor. Step S3: In the compensation model, assign non-uniform current weights to each power conductor. Step S4: Using an adaptive integral method, and based on the Biot-Savart law and the current weight, calculate the total compensation magnetic field generated at the magnetic sensor by the compensation model, and calculate the error correction factor based on the total compensation magnetic field. Step S5: Real-time acquisition of power conductor current, calculation of real-time interference magnetic field, and calculation of correction interference magnetic field based on error correction factor and real-time interference magnetic field. Step S6: Obtain the original aeromagnetic three-component data of the sensor in the three-dimensional spatial model, and use the differential method to remove the correction interference magnetic field from the original aeromagnetic three-component data to obtain the interference-free aeromagnetic three-component data.

[0007] The magnetic interference compensation method for UAV rotor power supply lines based on conductor space modeling provided by the present invention has the following beneficial effects: This invention constructs a compensation model composed of multiple power conductors based on the three-dimensional spatial path information and physical parameter information of the power conductors. This model can accurately simulate the conductor cross-section and current distribution, thus effectively considering the influence of the finite radius of the conductors and the current distribution within the cross-section on the accuracy of magnetic field calculation. In addition, the total compensation magnetic field generated at the magnetic sensor by the compensation model is calculated using an adaptive integration method, ensuring consistent high accuracy in near-field and far-field calculations. It can calculate and compensate for dynamically changing interference magnetic fields in real time and with high accuracy. Simulation results show that, using the method provided by this invention, after compensation of the total magnetic field strength, interference components in all directions are synergistically eliminated, and the overall magnetic field measurement accuracy is significantly improved, providing high-quality total field data for magnetic exploration. Attached Figure Description

[0008] Figure 1 A flowchart illustrating the magnetic interference compensation method for UAV rotor power supply lines based on conductor space modeling provided in this embodiment of the invention; Figure 2 A comparison diagram of the magnetic field strength of the X component before and after compensation; Figure 3 A comparison diagram of the Y-component magnetic field strength before and after compensation; Figure 4 A comparison diagram of the Z-component magnetic field strength before and after compensation; Figure 5 A comparison diagram of the total magnetic field strength before and after compensation. Detailed Implementation

[0009] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain embodiments of the present invention, and should not be construed as limiting the present invention.

[0010] Please see Figure 1 The present invention provides a method for compensating for magnetic interference in UAV rotor power supply lines based on conductor space modeling, comprising steps S1 to S6: Step S1: Obtain the three-dimensional spatial path information and physical parameter information of the power wire carrying current on the rotor arm of the UAV, as well as the installation position information of the magnetic sensor on the UAV, so as to construct a three-dimensional spatial model.

[0011] In this embodiment, a quadcopter drone is used as the implementation object. The drone has a symmetrical quadcopter layout with four rotor arms arranged in a cross shape, each arm being 0.25 meters long. The onboard magnetometer uses a three-way magnetic sensor and is rigidly mounted 1 meter directly below the drone's fuselage via a carbon fiber connecting rod. In the aircraft coordinate system, the magnetometer's installation position is at coordinates (0, 0, -1) meters.

[0012] The power cables supply power to four brushless motors, and the cable paths were precisely measured using a coordinate measuring machine. Each motor branch cable includes eight control points, accurately recording the complete routing path from the power management board to the motor. The cable radius is 0.8 mm, the conductor material is copper, and the resistivity is 1.68 × 10⁻⁶. -8 Ω·m.

[0013] Step S2: Based on the three-dimensional spatial path information and physical parameter information of the power conductor, a compensation model composed of multiple power conductors is constructed. The cross-sectional geometric features and current distribution of the power conductor are simulated through the compensation model.

[0014] The system defines a three-dimensional spatial path for the conductor, consisting of a sequence of discrete control points. These control points precisely describe the actual laying path of the conductor from the power distribution board to the brushless motor, including all bends and turns. The system inputs physical parameters of the conductor, including the radius of the power conductor, the conductor resistivity, and the total current flowing through the power conductor, as well as the installation coordinates of the magnetic sensor in the machine coordinate system as the target point.

[0015] In this embodiment, the number of power conductors in the compensation model is 19, specifically 1 central conductor and 18 surrounding conductors. The 18 conductors are distributed in three layers: 6 in the inner layer, 6 in the middle layer, and 6 in the outer layer.

[0016] Among them, the The offset of the root dynamic conductor relative to the central axis is calculated by the following formula:

[0017] in, For the first The offset of the root dynamic conductor relative to the central axis. Let be the radius of the power conductor. Index for circumferential angle distribution. , , For the first Each circumferential angle ensures that the six wires in each layer are evenly and symmetrically distributed on a circle (the angle between adjacent wires is 60°). This is the interlayer phase rotation angle. , This is the layer radius scaling factor.

[0018] when The offset of the corresponding center conductor is (0,0,0), which means that it has no offset on the set geometric center axis.

[0019] when Up to 7, corresponding to the outermost 6 wires, were arranged in a pattern... On a circle with radius , through angle The conductors are evenly distributed (with an angle of 60° between adjacent conductors), forming a regular hexagon.

[0020] when to 13 and Up to 19, these correspond to the wires in the middle and inner layers, respectively. (This is achieved through scaling factors.) , Arranged on a smaller circle, and rotated by a phase angle By arranging them in a staggered manner to fill the gaps in the outer conductor, the 19 conductors form a tight hexagonal stacked structure within the cross-section, more realistically simulating a solid conductor.

[0021] Step S3: In the compensation model, assign a non-uniform current weight to each power conductor.

[0022] Among them, the current weight of the power conductors decreases sequentially from the center to the outermost layer, and the current weight of all power conductors satisfies the following formula:

[0023] in, For the first Current weighting of the root dynamic conductor, This represents the total number of power conductors.

[0024] The above allocation strategy aims to approximate the skin effect of a conductor under high-frequency operating conditions.

[0025] Specifically, in this embodiment, the current weight of the central conductor is 0.25.

[0026] Step S4: Using an adaptive integral method, and based on the Biot-Savart law and the current weight, calculate the total compensation magnetic field generated at the magnetic sensor by the compensation model, and calculate the error correction factor based on the total compensation magnetic field.

[0027] The total compensation magnetic field is calculated using the following formula:

[0028]

[0029]

[0030] in, Indicates the total compensation magnetic field. Indicates the first The compensating magnetic field generated by the root power wire at the magnetic sensor. For micro-segment indexes of a single dynamic conductor, This represents the total number of micro-segments in a single power conductor. The permeability of free space, The total current flowing through the power conductor. For the first The vector of a micro-line segment The vector from the magnetic sensor to the midpoint of the micro-line segment; For the first The weighting coefficients of each micro-line segment in the numerical integration, in this embodiment, are the weighting coefficients of the first micro-line segment in the numerical integration. Take 0.5, the middle micro segment ( The weighting coefficient of ) is 1, and the first The weighting coefficient of each micro-segment in numerical integration Take 0.5; This indicates taking the maximum value; The minimum number of subdivision micro-segments is typically set to an integer between 100 and 500 to ensure basic accuracy. The length of a single power conductor segment; For accuracy control coefficients, The larger the value, the denser the subdivision, and the higher the computational accuracy. The smaller the value, the sparser the subdivision, and the faster the calculation speed. The value is usually between 1000 and 2000. The distance from the midpoint of the micro-line segment to the magnetic sensor is denoted as . This indicates rounding up to the nearest integer.

[0031] Then, the error correction factor is calculated using the following formula:

[0032] in, Indicates the error correction factor. Represents a known standard magnetic field. This indicates element-wise division.

[0033] Step S5: Real-time acquisition of the current in the power conductor, calculation of the real-time interference magnetic field, and calculation of the corrected interference magnetic field based on the error correction factor and the real-time interference magnetic field.

[0034] Specifically, step S5 includes: Real-time acquisition of current in power conductors ; use Calculate real-time disturbance magnetic field ; The corrected interference magnetic field is calculated based on the error correction factor and the real-time interference magnetic field, and its expression is:

[0035] in, This indicates correction of interfering magnetic fields. This indicates element-wise multiplication.

[0036] Step S6: Obtain the original aeromagnetic three-component data of the sensor in the three-dimensional spatial model, and use the differential method to remove the correction interference magnetic field from the original aeromagnetic three-component data to obtain the interference-free aeromagnetic three-component data.

[0037] Wherein, step S6 satisfies the following formula: ; in, This represents the aeromagnetic three-component data after interference removal. This represents the original aeromagnetic three-component data.

[0038] The following simulation test will be performed, specifically executing the following procedure at a frequency of 100Hz: First, collect the real-time current values ​​of the four motors simultaneously; Then read the raw aeromagnetic three-component data. ; The interference magnetic field is calculated in parallel for each motor branch, and the total compensation magnetic field is obtained by vector superposition. ; Further correction of the interference magnetic field ; Finally, the aeromagnetic three-component data after interference elimination are output. .

[0039] Test results are as follows Figures 2 to 5 As shown, from Figure 2It can be seen that after compensation processing, the X-component magnetic field data corrects the magnetic field measurement value from the original reference range of around -159 nT to near zero, effectively separating the influence of electromagnetic interference from the UAV's power conductor on the environmental magnetic field measurement. Figure 3 It can be seen that after compensation processing, the systematic bias in the Y-component magnetic field data is effectively eliminated, and the data more closely resembles the actual environmental magnetic field values, providing a reliable Y-axis magnetic field benchmark for geological interpretation. Figure 4 It can be seen that the Z component, as the vertical magnetic field component, successfully separated the vertical electromagnetic interference generated by the UAV's power conductor after compensation, making the vertical magnetic field measurement data more accurate and beneficial for the precise identification of underground targets. From Figure 5 It can be seen that after comprehensive compensation, the interference components in all directions are eliminated in a coordinated manner, and the overall magnetic field measurement accuracy is significantly improved, providing high-quality total field data for magnetic exploration.

[0040] In summary, the magnetic interference compensation method for UAV rotor power supply lines based on conductor space modeling according to the above embodiments has the following beneficial effects: This invention constructs a compensation model composed of multiple power conductors based on the three-dimensional spatial path information and physical parameter information of the power conductors. This model can accurately simulate the conductor cross-section and current distribution, thus effectively considering the influence of the finite radius of the conductors and the current distribution within the cross-section on the accuracy of magnetic field calculation. In addition, the total compensation magnetic field generated at the magnetic sensor by the compensation model is calculated using an adaptive integration method, ensuring consistent high accuracy in near-field and far-field calculations. It can calculate and compensate for dynamically changing interference magnetic fields in real time and with high accuracy. Simulation results show that, using the method provided by this invention, after compensation of the total magnetic field strength, interference components in all directions are synergistically eliminated, and the overall magnetic field measurement accuracy is significantly improved, providing high-quality total field data for magnetic exploration.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for compensating for magnetic interference in the power supply line of a UAV rotor based on conductor spatial modeling, characterized in that, include: Step S1: Obtain the three-dimensional spatial path information and physical parameter information of the power wire carrying current on the rotor arm of the UAV, as well as the installation position information of the magnetic sensor on the UAV, so as to construct a three-dimensional spatial model. Step S2: Based on the three-dimensional spatial path information and physical parameter information of the power conductor, a compensation model composed of multiple power conductors is constructed. The compensation model is used to simulate the cross-sectional geometric features and current distribution of the power conductor. Step S3: In the compensation model, assign non-uniform current weights to each power conductor. Step S4: Using an adaptive integral method, and based on the Biot-Savart law and the current weight, calculate the total compensation magnetic field generated at the magnetic sensor by the compensation model, and calculate the error correction factor based on the total compensation magnetic field. Step S5: Real-time acquisition of power conductor current, calculation of real-time interference magnetic field, and calculation of correction interference magnetic field based on error correction factor and real-time interference magnetic field. Step S6: Obtain the original aeromagnetic three-component data of the sensor in the three-dimensional spatial model, and use the differential method to remove the correction interference magnetic field from the original aeromagnetic three-component data to obtain the interference-free aeromagnetic three-component data.

2. The method for magnetic interference compensation of UAV rotor power supply lines based on conductor space modeling according to claim 1, characterized in that, The compensation model has 19 dynamic conductors, of which the first... The offset of the root dynamic conductor relative to the central axis is calculated by the following formula: in, For the first The offset of the root dynamic conductor relative to the central axis. Let be the radius of the power conductor. Index for circumferential angle distribution. , For the first An angle of a circle This is the interlayer phase rotation angle. , This is the layer radius scaling factor.

3. The method for magnetic interference compensation of UAV rotor power supply lines based on conductor space modeling according to claim 1, characterized in that, In step S3, the current weight of the power conductors decreases sequentially from the center to the outermost layer, and the current weight of all power conductors satisfies the following formula: in, For the first Current weighting of the root dynamic conductor, This represents the total number of power conductors.

4. The method for magnetic interference compensation of UAV rotor power supply lines based on conductor space modeling according to claim 3, characterized in that, In step S4, the total compensation magnetic field is calculated using the following formula: in, Indicates the total compensation magnetic field. Indicates the first The compensating magnetic field generated by the root power wire at the magnetic sensor. For micro-segment indexes of a single dynamic conductor, This represents the total number of micro-segments in a single power conductor. The permeability of free space, The total current flowing through the power conductor. For the first The vector of a micro-line segment The vector from the magnetic sensor to the midpoint of the micro-line segment. For the first The weighting coefficients of individual line segments in numerical integration. This indicates taking the maximum value. To be the minimum number of subdivided micro-segments, The length of a single power conductor segment. For accuracy control coefficients, The distance from the midpoint of the micro-line segment to the magnetic sensor is denoted as . This indicates rounding up to the nearest integer.

5. The method for magnetic interference compensation of UAV rotor power supply lines based on conductor space modeling according to claim 4, characterized in that, In step S4, the error correction factor is calculated using the following formula: in, Indicates the error correction factor. Represents a known standard magnetic field. This indicates element-wise division.

6. The method for compensating for magnetic interference in UAV rotor power supply lines based on conductor space modeling according to claim 5, characterized in that, Step S5 specifically includes: Real-time acquisition of current in power conductors ; use Calculate real-time disturbance magnetic field ; The corrected interference magnetic field is calculated based on the error correction factor and the real-time interference magnetic field, and its expression is: in, This indicates correction of interfering magnetic fields. This indicates element-wise multiplication.

7. The method for compensating for magnetic interference in UAV rotor power supply lines based on conductor space modeling according to claim 6, characterized in that, Step S6 satisfies the following formula: ； in, This represents the aeromagnetic three-component data after interference removal. This represents the original aeromagnetic three-component data.

8. The method for magnetic interference compensation of UAV rotor power supply lines based on conductor space modeling according to claim 1, characterized in that, The physical parameter information includes the radius of the power conductor, the resistivity of the conductor, and the total current flowing through the power conductor.

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