A magnetic suspension device control method for a versatile unmanned aerial vehicle

Abstract

The application discloses a kind of magnetic suspension device control method of full habitat unmanned aerial vehicle, it is related to unmanned aerial vehicle technical field.The method includes: based on magnetic circuit Kirchhoff law constructs equivalent magnetic circuit and solves main air gap magnetic flux, calculates electromagnetic suspension force using virtual displacement principle, and torque is solved by geometric analysis and cross multiplication operation.Suspension gap is deduced using Hall sensor, and equation set is constructed to solve floater space position and total suspension force.Through establishing floater dynamics equation, control voltage is generated using virtual magnetic flux cascade control structure, and temperature and inductance change are corrected in real time.Taylor expansion is used to linearly approximate nonlinear electromagnetic force, PID parameters are dynamically adjusted, and finally PWM signal is generated to drive coil.The application is contactless suspension and drive, discards traditional mechanical slip ring and connecting rod, significantly reduces weight, improves energy efficiency and response speed, and has excellent waterproof and dustproof ability.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) technology, and in particular to a control method for a magnetic levitation device of an amphibious UAV. Background Technology

[0002] Existing amphibious drones generally adopt a "split-type" design, which is essentially a simple stacking of functional modules, resulting in a bulky system, low energy efficiency, and insufficient reliability. For example, amphibious robots typically integrate modules and add functions. This design results in the robot carrying two independent modules for aerial flight and water surface floating, which not only makes the overall structure complex and bulky but also reduces power efficiency. Module splicing also introduces more sealing points and mechanical interfaces, which can become potential weak points in complex environments.

[0003] Amphibious drones typically integrate two independent modules for aerial flight and water surface afloatation, which not only results in structural redundancy and a significant increase in weight, but also leads to a substantial decrease in power efficiency. In addition, the mechanical interfaces and sealing points between the modules are prone to becoming weak points in case of failure.

[0004] Traditional UAVs rely heavily on mechanical slip rings, servos, and linkages for pitch control, resulting in complex system structures, slow response, and a high risk of jamming or failure in harsh environments such as water or dust, which severely restricts the environmental adaptability and operational efficiency of amphibious UAVs. Summary of the Invention

[0005] The purpose of this invention is to provide a control method for the magnetic levitation device of an amphibious unmanned aerial vehicle, which aims to solve or improve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides the following solution: A method for controlling the magnetic levitation device of an amphibious unmanned aerial vehicle, comprising: Based on Kirchhoff's laws for magnetic circuits, an equivalent magnetic circuit including the iron core, air gap, and leakage flux is constructed, and the main air gap flux is solved. The electromagnetic levitation force in the vertical direction is calculated based on the main air gap magnetic flux using the principle of virtual displacement. The equivalent magnetic field strength is measured, a generalized force matrix model is constructed based on the Lorentz force, and the point of application of the equivalent resultant force is determined through geometric analysis. The torque is then calculated using the cross product. The air gap magnetic flux density is measured using a Hall effect sensor to infer the suspension gap. Based on the suspension gap measured by multiple Hall sensors, a system of equations is constructed to calculate the spatial position of the float, and a force model transformation is performed based on the magnetic flux density to generate the total levitation force of the float; The dynamic equations of the float are constructed, and a cascade control structure with virtual magnetic flux is used to generate the control voltage; Corrections are made based on changes in coil resistance caused by temperature variations and changes in inductance caused by variations in the suspension gap. By using Taylor expansion to make a linear approximation of the nonlinear electromagnetic force near the equilibrium point, the current system stiffness is calculated, and the gain parameters of the PID controller are dynamically adjusted to finally generate a PWM signal to drive the coil.

[0007] Furthermore, based on Kirchhoff's laws for magnetic circuits, an equivalent magnetic circuit including the iron core, air gap, and leakage flux is constructed, and the main air gap flux is solved, including: The expression for the equivalent magnetic circuit model is: In the formula, This refers to the number of turns in the coil winding. This is the current flowing through the coil; Main air gap magnetic flux; For air gap reluctance; For iron core magnetic reluctance; Leakage flux; The equivalent magnetic reluctance of the leakage flux path; This represents the total magnetic flux generated by the coil.

[0008] Furthermore, based on the main air gap magnetic flux, the electromagnetic levitation force in the vertical direction is calculated using the principle of virtual displacement, including: The expression for electromagnetic levitation force is: In the formula, The electromagnetic levitation force is in the vertical direction; For air gap reluctance; Main air gap magnetic flux; This refers to the levitation gap between the float and the electromagnetic coil.

[0009] Furthermore, the equivalent magnetic field strength is measured, a generalized force matrix model is constructed based on the Lorentz force, and the point of application of the equivalent resultant force is determined through geometric analysis. The torque is calculated using the cross product, including: Construct a coordinate system with the center of the coil array as the origin. The Lorentz force is extended into matrix form, and its expression is: In the formula, This refers to the generalized force vector acting on the coil array, including three-dimensional force and three-dimensional torque; This is the electromagnetic force coefficient matrix; This is the driving current vector of the coil; The point of application of the equivalent resultant force is determined through geometric analysis, and the torque is calculated using the cross product. The expression is as follows: In the formula, The electromagnetic torque vector acting on the float; The position vector pointing from the center of mass of the float to the point of application of the equivalent resultant force; This is the equivalent resultant force acting on the float.

[0010] Furthermore, the air gap magnetic induction intensity is measured using a Hall sensor to infer the levitation gap, including: The basic expression for the Hall effect is: In the formula, The Hall voltage output by the Hall element; Hall coefficient; The control current flowing through the Hall element; The magnetic flux density passing perpendicularly through the Hall element; The thickness of the sensitive layer of the Hall element; Considering the interference of the coil current i on the magnetic field, an engineering fitting formula is constructed to deduce the suspension gap, and the expression is: In the formula, This is the actual output voltage of the Hall sensor; The suspension gap to be determined; The excitation current of the coil; , , These are the zero-point offset, magnetic field gradient coefficient, and current coupling coefficient, respectively.

[0011] Furthermore, based on the suspension gap measured by multiple Hall sensors, a system of equations is constructed to calculate the spatial position of the float, and a force model transformation is performed based on the magnetic flux density to generate the total levitation force of the float, including: By arranging multiple Hall sensors, a system of equations is constructed to solve for the spatial position of the float, expressed as: In the formula, Let n be the output voltage of the i-th Hall sensor; n is the number of Hall sensors. These represent the three-dimensional position coordinates and attitude variables of the float in the spatial coordinate system. The total levitation force is transformed into a function based on the compensated magnetic flux density, expressed as: In the formula, The total levitation force acting on the float; , , These are the coefficients of a second-order polynomial; The compensated magnetic flux density; The force coefficient of electromagnetic force; This refers to the number of coil turns. The coil current; The distance constant of the permanent magnet; This is a suspension gap.

[0012] Furthermore, the dynamic equations of the float are constructed, and a cascaded control structure of virtual magnetic flux is used to generate the control voltage, including: Based on Newton's second law, the dynamic equation of the float in the vertical direction with a single degree of freedom is established, and the expression is: In the formula, The mass of the float; for; It is the acceleration due to gravity; External interference force; For the current and suspension gap The total levitation force changes; The cascade control structure for virtual flux includes: The position loop collects the actual gap, calculates the deviation from the target suspension gap, and outputs the desired virtual magnetic flux through the position controller PID. For a flux loop, the actual magnetic flux is calculated based on the measured current and the levitation gap. The expression is as follows: In the formula This represents the actual total magnetic flux of the coil circuit; The dynamic inductance varies with the gap; The coupled magnetic flux generated by the permanent magnet and passing through the coil; This is the measured current; This is the measured gap; The control voltage is generated by inversely solving the coil voltage balance equation, and its expression is as follows: In the formula, This is the control voltage applied across the coil. This is the equivalent resistance of the coil; denoted as the rate of change of magnetic flux over time.

[0013] Furthermore, the expression for the PID control law of the position controller is: In the formula, Let t be the target excitation current output by the controller; Let be the magnetic levitation position control error at time t; Let be the target suspension gap at time t; The measured suspension gap is calculated by back-calculating the Hall sensor voltage at time t. , , Let be the proportional, integral, and derivative gain parameters, respectively.

[0014] Furthermore, corrections are made based on the changes in coil resistance caused by temperature variations and the changes in inductance caused by variations in the suspension gap, including: The inductance parameters change dynamically with the levitation gap and current, as expressed by: In the formula, To account for the real-time inductance value after considering magnetic saturation and leakage flux; The vacuum permeability; This refers to the number of turns in the coil winding; The effective cross-sectional area of ​​the magnetic pole; For real-time floating gap; Correction factors to account for leakage flux and magnetic saturation; The physical relationship between levitation force and electric current is used for auxiliary identification and verification, expressed as follows: In the formula, The inductance value is derived by inversely using mechanical relationships; The levitation force at the current moment; This represents the coil current at the current moment; Resistance correction is performed using a linear model based on the temperature coefficient, expressed as follows: In the formula, Current temperature Real-time coil resistance value; For the coil at standard room temperature The nominal resistance value below; The temperature coefficient of resistance of the coil conductor material; This refers to the real-time operating temperature of the coil. This is the standard reference temperature.

[0015] Furthermore, a Taylor expansion is used to approximate the nonlinear electromagnetic force linearly near the equilibrium point, the current system stiffness is calculated, and the gain parameters of the PID controller are dynamically adjusted to ultimately generate a PWM signal to drive the coil, including: The expression for the nonlinear electromagnetic resultant force is: In the formula, For any current and suspension gap Nonlinear electromagnetic resultant force; To reach the equilibrium point Steady-state electromagnetic force at the location; This represents the increase in electromagnetic force caused by the current deviation. This represents the increase in electromagnetic force caused by displacement deviation. This is the current stiffness coefficient; This is the displacement stiffness coefficient.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention discloses a control method for a magnetic levitation device in an amphibious unmanned aerial vehicle (UAV). By introducing a magnetic levitation device and contactless variable-pitch control, this method fundamentally solves the structural redundancy and reliability problems associated with traditional modular designs. Utilizing a magnetic field to achieve contactless levitation and actuation completely eliminates mechanical slip rings, linkages, and other transmission components, significantly reducing system weight and mechanical friction loss, thereby greatly improving power efficiency and response speed. Simultaneously, eliminating physical contact surfaces provides excellent waterproof and dustproof capabilities, effectively overcoming the risks of jamming and wear in harsh environments. Attached Figure Description

[0017] 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 introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the control circuit architecture of the magnetic levitation device according to the method of the present invention; Figure 2 This is a schematic diagram of the forces acting on the float of the magnetic levitation device in this embodiment when it is levitated; Figure 3 This is a schematic diagram of the Hall effect in this embodiment; Figure 4 This is a schematic diagram of the positional PID algorithm in this embodiment; Figure 5 This is a flowchart of the magnetic levitation detection and control program in this embodiment. Detailed Implementation

[0019] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a control method for the magnetic levitation device of an amphibious unmanned aerial vehicle, which aims to solve or improve at least one of the above-mentioned technical problems.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, the present invention provides a control method for a magnetic levitation device of an amphibious unmanned aerial vehicle, comprising: like Figure 2 The diagram shows the force analysis of the battery device. The electromagnetic force F generated by the electromagnetic coil i balances the weight of the float, making the float suspend in the air. The float is adjusted to move and lock into place quickly between the upper and lower slots of the drive slot component, corresponding to high and low pitches respectively, so as to realize the rapid pitch change of the UAV.

[0023] Step 1: Based on Kirchhoff's laws for magnetic circuits, construct an equivalent magnetic circuit including the iron core, air gap, and leakage flux, and solve for the main air gap flux, including: The expression for the equivalent magnetic circuit model is: In the formula, This refers to the number of turns in the coil winding. This is the current flowing through the coil; The main air gap flux represents the working magnetic flux that generates effective electromagnetic force through the air gap. The air gap reluctance represents the resistance of the air gap to magnetic flux, which is directly proportional to the suspension gap z and inversely proportional to the cross-sectional area. The magnetic reluctance of the iron core represents the resistance to magnetic flux within the ferromagnetic material, which increases with increasing magnetic flux density (magnetic saturation effect). Leakage flux refers to magnetic flux that does not pass through the air gap but closes through other paths (such as circulating in the air) and does not participate in work. The equivalent magnetic reluctance of the leakage flux path; This represents the total magnetic flux generated by the coil.

[0024] In the above steps, when solving the equivalent magnetic circuit model, consider The nonlinear relationship with magnetic flux variation is addressed by introducing a BH curve lookup table method.

[0025] Step 2: Based on the main air gap magnetic flux, calculate the vertical electromagnetic levitation force using the principle of virtual displacement. This force is used to balance gravity and drive the positioning mechanism. The expression is: In the formula, The electromagnetic levitation force is in the vertical direction; For air gap reluctance; Main air gap magnetic flux; This refers to the levitation gap between the float and the electromagnetic coil.

[0026] Step 3: Measure the equivalent magnetic field strength, construct a generalized force matrix model based on the Lorentz force, determine the point of application of the equivalent resultant force through geometric analysis, and calculate the torque using the cross product, including: Construct a coordinate system with the center of the coil array as the origin. The Lorentz force is extended into matrix form, and its expression is: In the formula, This refers to the generalized force vector acting on the coil array, including three-dimensional force and three-dimensional torque; This is the electromagnetic force coefficient matrix obtained through static calibration; This is the driving current vector of the coil; The point of application of the equivalent resultant force is determined through geometric analysis, and the torque is calculated using the cross product. The expression is as follows: In the formula, The electromagnetic torque vector acting on the float; The position vector pointing from the center of mass of the float to the point of application of the equivalent resultant force; This is the equivalent resultant force acting on the float.

[0027] like Figure 3 As shown, step 4 involves using a Hall sensor to measure the air gap magnetic induction intensity and then inferring the levitation gap, including: The basic expression for the Hall effect is: In the formula, The Hall voltage output by the Hall element; The Hall coefficient depends on the properties of the semiconductor material; The control current flowing through the Hall element; The magnetic flux density passing perpendicularly through the Hall element; The thickness of the sensitive layer of the Hall element; Considering the interference of the coil current i on the magnetic field, an engineering fitting formula is constructed to deduce the suspension gap, and the expression is: In the formula, This is the actual output voltage of the Hall sensor; The suspension gap to be determined; The excitation current of the coil; , , The fitting coefficients obtained through static calibration experiments are denoted as zero-point offset, magnetic field gradient coefficient, and current coupling coefficient, respectively.

[0028] like Figure 5 As shown, in step 5, based on the suspension gap measured by multiple Hall sensors, a system of equations is constructed to calculate the spatial position of the float, and a force model transformation is performed based on the magnetic flux density to generate the total levitation force of the float, including: By arranging multiple Hall sensors, a system of equations is constructed to solve for the spatial position of the float, expressed as: In the formula, Let n be the output voltage of the i-th Hall sensor; n is the number of Hall sensors. These represent the three-dimensional position coordinates and attitude variables of the float in the spatial coordinate system. To reduce nonlinearity, the total levitation force is transformed into a function based on the compensated magnetic flux density, expressed as: In the formula, The total levitation force acting on the float; , , These are the coefficients of the second-order polynomial obtained by fitting experimental data; The magnetic flux density measured by the Hall sensor after temperature or interference compensation; The force coefficient of electromagnetic force; This refers to the number of coil turns. The coil current; The distance constant of the permanent magnet; This is a suspension gap.

[0029] Step 6: Construct the dynamic equations of the float and generate the control voltage using a cascaded control structure with virtual magnetic flux, including: Based on Newton's second law, the dynamic equation of the float in the vertical direction with a single degree of freedom is established, and the expression is: In the formula, The mass of the float; for; It is the acceleration due to gravity; External interference force; For the current and suspension gap The total levitation force changes; The cascade control structure for virtual flux includes: The position loop collects the actual gap, calculates the deviation from the target suspension gap, and outputs the desired virtual magnetic flux through the position controller PID. like Figure 4 As shown, the expression for the PID control law is: In the formula, The target excitation current output by the controller at time t is the final control quantity calculated by the position controller PID, which is used to drive the power amplifier to output the corresponding coil current. Let be the magnetic levitation position control error at time t; Let be the target suspension gap at time t; The measured suspension gap is calculated by back-calculating the Hall sensor voltage at time t. , , Let be the proportional, integral, and derivative gain parameters, respectively; For a flux loop, the actual magnetic flux is calculated based on the measured current and the levitation gap. The expression is as follows: In the formula This represents the actual total magnetic flux of the coil circuit; The dynamic inductance varies with the gap; The coupled magnetic flux generated by the permanent magnet and passing through the coil; This is the measured current; This is the measured gap; The control voltage is generated by inversely solving the coil voltage balance equation, and its expression is as follows: In the formula, This is the control voltage applied across the coil. This is the equivalent resistance of the coil; The rate of change of magnetic flux over time is calculated by the position controller PID based on the magnetic flux deviation and is used to drive the magnetic flux to track the desired virtual magnetic flux.

[0030] Step 7: Correct the changes based on the coil resistance caused by temperature variations and the inductance caused by changes in the floating gap, including: Considering the effects of magnetic saturation and leakage flux, the inductance parameters dynamically change with the levitation gap and current, as expressed by: In the formula, To account for the real-time inductance value after considering magnetic saturation and leakage flux; The vacuum permeability; This refers to the number of turns in the coil winding; The effective cross-sectional area of ​​the magnetic pole; For real-time floating gap; The correction factor for leakage flux and magnetic saturation is related to the current. The functions are pre-calibrated experimentally and stored in a lookup table for real-time querying; The physical relationship between levitation force and electric current is used for auxiliary identification and verification, expressed as follows: In the formula, The inductance value is derived from the mechanical relationship and is used to verify the accuracy of the estimation model; The levitation force at the current moment; This represents the coil current at the current moment; Since the coil generates heat during prolonged operation, its resistance increases with temperature. A linear model based on the temperature coefficient is used for resistance correction, expressed as: In the formula, Current temperature Real-time coil resistance value; For the coil at standard room temperature The nominal resistance value below; The temperature coefficient of resistance of the coil conductor material; The real-time operating temperature of the coil is collected in real time by a temperature sensor (such as an NTC thermistor) attached to the coil frame. This is the standard reference temperature.

[0031] Step 8: Using Taylor expansion, a linear approximation of the nonlinear electromagnetic force is made near the equilibrium point. The current system stiffness is calculated, and the gain parameters of the PID controller are dynamically adjusted. Finally, a PWM signal is generated to drive the coil. The expression is: In the formula, For any current and suspension gap Nonlinear electromagnetic resultant force; To reach the equilibrium point Steady-state electromagnetic force at the location; This represents the increase in electromagnetic force caused by the current deviation. This represents the increase in electromagnetic force caused by displacement deviation. This is the current stiffness coefficient; This is the displacement stiffness coefficient.

[0032] This invention relates to the pitch mechanism of an amphibious unmanned aerial vehicle (UAV). Through the interaction between the electromagnetic levitation device (stator) and the float (mover / float), and by using a PID algorithm combined with Hall effect feedback, the float is precisely controlled to move rapidly and lock into position between the upper and lower slots of the drive slot component, thereby achieving rapid switching between high and low pitch and stable levitation of the UAV propeller blades.

[0033] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0034] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A control method for a magnetic levitation device of an amphibious unmanned aerial vehicle, characterized in that, include: Based on Kirchhoff's laws for magnetic circuits, an equivalent magnetic circuit including the iron core, air gap, and leakage flux is constructed, and the main air gap flux is solved. The electromagnetic levitation force in the vertical direction is calculated based on the main air gap magnetic flux using the principle of virtual displacement. The equivalent magnetic field strength is measured, a generalized force matrix model is constructed based on the Lorentz force, and the point of application of the equivalent resultant force is determined through geometric analysis. The torque is then calculated using the cross product. The air gap magnetic flux density is measured using a Hall sensor to infer the suspension gap. Based on the suspension gap measured by multiple Hall sensors, a system of equations is constructed to calculate the spatial position of the float, and a force model transformation is performed based on the magnetic flux density to generate the total levitation force of the float; The dynamic equations of the float are constructed, and a cascade control structure with virtual magnetic flux is used to generate the control voltage; Corrections are made based on changes in coil resistance caused by temperature variations and changes in inductance caused by variations in the suspension gap. By using Taylor expansion to make a linear approximation of the nonlinear electromagnetic force near the equilibrium point, the current system stiffness is calculated, and the gain parameters of the PID controller are dynamically adjusted to finally generate a PWM signal to drive the coil.

2. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The process involves constructing an equivalent magnetic circuit including the iron core, air gap, and leakage flux, based on Kirchhoff's laws for magnetic circuits, and solving for the main air gap flux, including: The expression for the equivalent magnetic circuit model is: In the formula, This refers to the number of turns in the coil winding; This is the current flowing through the coil; Main air gap magnetic flux; For air gap reluctance; For iron core magnetic reluctance; Leakage flux; The equivalent magnetic reluctance of the leakage flux path; This represents the total magnetic flux generated by the coil.

3. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The calculation of the vertical electromagnetic levitation force based on the main air gap magnetic flux and the principle of virtual displacement includes: The expression for electromagnetic levitation force is: In the formula, The electromagnetic levitation force is in the vertical direction; For air gap reluctance; Main air gap magnetic flux; This refers to the levitation gap between the float and the electromagnetic coil.

4. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The measurement of the equivalent magnetic field strength involves constructing a generalized force matrix model based on the Lorentz force, determining the point of application of the equivalent resultant force through geometric analysis, and calculating the torque using the cross product, including: Construct a coordinate system with the center of the coil array as the origin. The Lorentz force is extended into matrix form, and its expression is: In the formula, This refers to the generalized force vector acting on the coil array, including three-dimensional force and three-dimensional torque; This is the electromagnetic force coefficient matrix; This is the driving current vector of the coil; The point of application of the equivalent resultant force is determined through geometric analysis, and the torque is calculated using the cross product. The expression is as follows: In the formula, This is the electromagnetic torque vector acting on the float; The position vector pointing from the center of mass of the float to the point of application of the equivalent resultant force; This is the equivalent resultant force acting on the float.

5. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The method of using a Hall sensor to measure the air gap magnetic induction intensity and then inferring the suspension gap includes: The basic expression for the Hall effect is: In the formula, The Hall voltage output by the Hall element; Hall coefficient; The control current flowing through the Hall element; The magnetic flux density passing perpendicularly through the Hall element; The thickness of the sensitive layer of the Hall element; Considering the interference of the coil current i on the magnetic field, an engineering fitting formula is constructed to deduce the suspension gap, and the expression is: In the formula, This is the actual output voltage of the Hall sensor; The suspension gap to be determined; The excitation current of the coil; , , These are the zero-point offset, magnetic field gradient coefficient, and current coupling coefficient, respectively.

6. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The process involves constructing a system of equations based on the suspension gap measured by multiple Hall sensors to calculate the spatial position of the float, and performing a force model transformation based on magnetic flux density to generate the total levitation force of the float, including: By arranging multiple Hall sensors, a system of equations is constructed to calculate the spatial position of the float, expressed as: In the formula, Let n be the output voltage of the i-th Hall sensor; n is the number of Hall sensors. These represent the three-dimensional position coordinates and attitude variables of the float in the spatial coordinate system. The total levitation force is transformed into a function based on the compensated magnetic flux density, expressed as: In the formula, The total levitation force acting on the float; , , These are the coefficients of a second-order polynomial; The compensated magnetic flux density; The force coefficient of electromagnetic force; This refers to the number of coil turns. The coil current; The distance constant of the permanent magnet; This is a suspension gap.

7. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The construction of the buoy's dynamic equations and the generation of control voltage using a cascaded control structure with virtual magnetic flux include: Based on Newton's second law, the dynamic equation of the float in the vertical direction with a single degree of freedom is established, and the expression is: In the formula, The mass of the float; for; It is the acceleration due to gravity; External interference force; For the current and suspension gap The total levitation force changes; The cascade control structure for virtual flux includes: The position loop collects the actual gap, calculates the deviation from the target suspension gap, and outputs the desired virtual magnetic flux through the position controller PID. For a flux loop, the actual magnetic flux is calculated based on the measured current and the levitation gap. The expression is as follows: In the formula This represents the actual total magnetic flux of the coil circuit; The dynamic inductance varies with the gap; The coupled magnetic flux generated by the permanent magnet and passing through the coil; This is the measured current; This is the measured gap; The control voltage is generated by inversely solving the coil voltage balance equation, and its expression is as follows: In the formula, This is the control voltage applied across the coil. This is the equivalent resistance of the coil; denoted as the rate of change of magnetic flux over time.

8. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 7, characterized in that, The expression for the PID control law of the position controller is: In the formula, Let t be the target excitation current output by the controller; Let be the magnetic levitation position control error at time t; Let be the target suspension gap at time t; The measured suspension gap is calculated by back-calculating the Hall sensor voltage at time t. , , Let be the proportional, integral, and derivative gain parameters, respectively.

9. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The correction based on changes in coil resistance due to temperature variations and changes in inductance due to changes in the suspension gap includes: The inductance parameters change dynamically with the levitation gap and current, as expressed by: In the formula, To account for the real-time inductance value after considering magnetic saturation and leakage flux; The vacuum permeability; This refers to the number of turns in the coil winding; The effective cross-sectional area of ​​the magnetic pole; For real-time floating gap; Correction factors to account for leakage flux and magnetic saturation; The physical relationship between levitation force and electric current is used for auxiliary identification and verification, expressed as follows: In the formula, The inductance value is derived by inversely using mechanical relationships; The levitation force at the current moment; This represents the coil current at the current moment; Resistance correction is performed using a linear model based on the temperature coefficient, expressed as follows: In the formula, Current temperature Real-time coil resistance value; For the coil at standard room temperature The nominal resistance value below; The temperature coefficient of resistance of the coil conductor material; This refers to the real-time operating temperature of the coil. This is the standard reference temperature.

10. The control method for the magnetic levitation device of an amphibious unmanned aerial vehicle according to claim 1, characterized in that, The method involves using Taylor expansion to make a linear approximation of the nonlinear electromagnetic force near the equilibrium point, calculating the current system stiffness, dynamically adjusting the gain parameters of the PID controller, and finally generating a PWM signal to drive the coil, including: The expression for the nonlinear electromagnetic resultant force is: In the formula, For any current and suspension gap Nonlinear electromagnetic resultant force; To reach the equilibrium point Steady-state electromagnetic force at the location; This represents the increase in electromagnetic force caused by the current deviation. This represents the increase in electromagnetic force caused by displacement deviation; This is the current stiffness coefficient; This is the displacement stiffness coefficient.

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