Real-time test method, electronic equipment and medium for lift-to-drag ratio of solar-powered UAV

Abstract

The present application discloses a real-time test method, electronic device, and medium for the lift-to-drag ratio of a solar drone. The method may include: establishing an axial unilateral equivalent magnetic circuit model of the solar drone, calculating the total magnetic resistance of the magnetic circuit; calculating the resultant magnetic force generated by the magnetic bearing based on the total magnetic resistance; calculating the thrust of the solar drone based on the resultant magnetic force generated by the magnetic bearings of each propulsion system; calculating the lift and drag of the solar drone, and then calculating the lift-to-drag ratio. The present invention is based on an axial pure electromagnetic bearing and can achieve real-time acquisition of the lift-to-drag ratio of a solar drone during flight without adding any additional hardware equipment. It is simple, practical, feasible, and has a clear physical meaning. Combined with parameter information such as the drone's attitude at the corresponding moment, it can be effectively applied to the overall aerodynamic performance analysis of solar drones, and plays a guiding role in the overall design of solar drones.

Description

Technical Field

[0001] The present invention relates to the field of solar-powered unmanned aerial vehicles (UAVs), and more particularly to a real-time test method, electronic equipment, and medium for testing the lift-to-drag ratio of a solar-powered UAV. Background Art

[0002] Solar-powered drones are a new type of aircraft with great development potential. Powered by solar energy, they require no fuel and can theoretically remain airborne forever. Compared to conventional drones, solar-powered drones offer high altitudes, extremely long flight times, and extremely high energy efficiency requirements. A solar-powered drone's lift-to-drag ratio directly impacts its payload capacity, altitude, and flight time, making it a core design metric. Therefore, the design complexity of this metric is crucial. Currently, there are limited methods for testing the lift-to-drag ratio of solar-powered drones. Most methods rely on flight data such as speed and acceleration to estimate the lift-to-drag ratio, and their accuracy is unknown.

[0003] Therefore, it is necessary to develop a real-time test method, electronic equipment and medium for the lift-to-drag ratio of a solar-powered UAV.

[0004] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0005] The present invention proposes a real-time test method, electronic equipment, and medium for the lift-to-drag ratio of a solar-powered unmanned aerial vehicle (UAV). The method is based on an axial pure electromagnetic bearing and can achieve real-time acquisition of the lift-to-drag ratio of a solar-powered UAV during flight without adding any additional hardware. The method is simple, practical, feasible, and has a clear physical meaning. Combined with parameter information such as the UAV's attitude at the corresponding moment, it can be effectively applied to the overall aerodynamic performance analysis of the solar-powered UAV, and plays a guiding role in the overall design of the solar-powered UAV.

[0006] In a first aspect, an embodiment of the present disclosure provides a real-time test method for lift-to-drag ratio of a solar-powered UAV, comprising:

[0007] Establish an axial single-sided equivalent magnetic circuit model for a solar drone and calculate the total magnetic resistance of the magnetic circuit;

[0008] Calculating the resultant magnetic force generated by the magnetic bearing according to the total magnetic resistance;

[0009] Calculating the thrust of the solar drone based on the resultant magnetic force generated by the magnetic bearings of each propulsion system;

[0010] The lift and drag of the solar-powered drone are calculated, and then the lift-to-drag ratio is calculated.

[0011] Preferably, calculating the resultant magnetic force generated by the magnetic bearing includes:

[0012] Calculate the suction force generated by the magnetic bearings on the positive and negative sides of the x-axis respectively based on the total magnetic resistance;

[0013] The resultant magnetic force generated by the magnetic bearing is calculated based on the suction force generated by the magnetic bearing on the positive and negative sides of the x-axis.

[0014] Preferably, the suction force generated by the magnetic bearing on the positive side of the x-axis is calculated by formula (1):

[0015]

[0016] Among them, F x is the suction force generated by the magnetic bearing on the positive side of the x-axis, R is the total magnetic resistance, r1, r2, r3, and r4 are the inner ring outer diameter, inner ring inner diameter, outer ring inner diameter, and outer ring outer diameter of the stator respectively, N is the number of coil turns, μ0 is the vacuum permeability, and i1 is the current in the coil on the positive side of the x-axis.

[0017] Preferably, the suction force generated by the magnetic bearing on the negative side of the x-axis is calculated by formula (2):

[0018]

[0019] Among them, F -x is the suction force generated by the magnetic bearing on the negative side of the x-axis, and i2 is the current of the coil on the negative side of the x-axis.

[0020] Preferably, the magnetic force generated by the magnetic bearing is calculated by formula (3):

[0021] F=F -x -F x +m1a x (3)

[0022] Where F is the magnetic force generated by the magnetic bearing, and m1 is the mass of the rotor system.

[0023] Preferably, the thrust of the solar drone is calculated by formula (4):

[0024]

[0025] Among them, F t is the thrust of the solar drone, F j is the resultant magnetic force generated by the magnetic bearings of the j-th propulsion system, and n is the number of propulsion systems.

[0026] Preferably, the lift of the solar drone is calculated by formula (5):

[0027] F f =ma z +G (5)

[0028] The resistance of the solar drone is calculated by formula (6):

[0029] F r =F t -ma x (6)

[0030] Among them, F f is the lift, F r is the resistance, m is the mass of the solar drone, G is the gravity of the solar drone, a z is the upward acceleration at the current moment.

[0031] Preferably, the lift-to-drag ratio is calculated by formula (7):

[0032] K=F f / F r (7)

[0033] Where K is the lift-to-drag ratio.

[0034] As a specific implementation of the embodiment of the present disclosure,

[0035] In a second aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0036] a memory storing executable instructions;

[0037] A processor runs the executable instructions in the memory to implement the real-time test method for the lift-to-drag ratio of a solar-powered UAV.

[0038] In a third aspect, an embodiment of the present disclosure further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the real-time test method for the lift-to-drag ratio of a solar-powered UAV.

[0039] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0041] Figure 1 A cross-sectional schematic diagram of an axial magnetic levitation bearing for a solar-powered drone according to an embodiment of the present invention is shown.

[0042] Figure 2a and Figure 2b Schematic diagrams of magnetic circuit area division and equivalent magnetic circuit according to an embodiment of the present invention are respectively shown.

[0043] Figure 3 A flowchart showing the steps of a method for real-time testing the lift-to-drag ratio of a solar-powered drone according to one embodiment of the present invention is shown.

[0044] Figure 4 A schematic diagram of a solar-powered drone according to an embodiment of the present invention is shown.

[0045] Description of reference numerals:

[0046] 1. Stator core in the positive direction of x; 2. Coil in the positive direction of x; 3. Coil in the negative direction of x; 4. Stator core in the negative direction of x; 5. Rotor shaft; 5-a. Thrust plate on the rotor shaft. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0048] The present invention provides a real-time test method for lift-to-drag ratio of a solar-powered UAV, comprising:

[0049] Establish an axial single-sided equivalent magnetic circuit model for a solar drone and calculate the total magnetic resistance of the magnetic circuit;

[0050] Based on the total magnetic resistance, calculate the magnetic force generated by the magnetic bearing;

[0051] Calculate the thrust of the solar drone based on the resultant magnetic force generated by the magnetic bearings of each propulsion system;

[0052] Calculate the lift and drag of a solar-powered drone, and then calculate the lift-to-drag ratio.

[0053] In one example, calculating the resultant magnetic force generated by a magnetic bearing includes:

[0054] Based on the total magnetic resistance, calculate the suction force generated by the magnetic bearing on the positive and negative sides of the x-axis respectively;

[0055] Based on the suction force generated by the magnetic bearing on the positive and negative sides of the x-axis, the resultant magnetic force generated by the magnetic bearing is calculated.

[0056] In one example, the suction force generated by the magnetic bearing on the positive side of the x-axis is calculated using formula (1):

[0057]

[0058] Among them, F x is the suction force generated by the magnetic bearing on the positive side of the x-axis, R is the total magnetic resistance, r1, r2, r3, and r4 are the inner ring outer diameter, inner ring inner diameter, outer ring inner diameter, and outer ring outer diameter of the stator respectively, N is the number of coil turns, μ0 is the vacuum permeability, and i1 is the current in the coil on the positive side of the x-axis.

[0059] In one example, the suction force generated by the magnetic bearing on the negative side of the x-axis is calculated using formula (2):

[0060]

[0061] Among them, F -x is the suction force generated by the magnetic bearing on the negative side of the x-axis, and i2 is the current of the coil on the negative side of the x-axis.

[0062] In one example, the magnetic force generated by the magnetic bearing is calculated using formula (3):

[0063] F=F -x -F x +m1a x (3)

[0064] Where F is the magnetic force generated by the magnetic bearing, and m1 is the mass of the rotor system.

[0065] In one example, the thrust of a solar-powered drone is calculated using formula (4):

[0066]

[0067] Among them, F t is the thrust of the solar drone, F j is the resultant magnetic force generated by the magnetic bearings of the j-th propulsion system, and n is the number of propulsion systems.

[0068] In one example, the lift of a solar-powered drone is calculated using formula (5):

[0069] F f =ma z +G(5)

[0070] The drag of the solar drone is calculated using formula (6):

[0071] F r =F t -ma x (6)

[0072] Among them, F f is the lift, F r is the resistance, m is the mass of the solar drone, G is the gravity of the solar drone, a z is the upward acceleration at the current moment.

[0073] In one example, the lift-to-drag ratio is calculated using formula (7):

[0074] K=F f / F(7)

[0075] Where K is the lift-to-drag ratio.

[0076] Figure 1 A cross-sectional schematic diagram of an axial magnetic levitation bearing for a solar-powered drone according to an embodiment of the present invention is shown.

[0077] Specifically, the principle of this method focuses on obtaining the thrust of solar drones. For any magnetic bearing structure, there is an equivalent magnetic circuit, so the magnetic circuit analysis and thrust solution modeling principles of this method are applicable to all types of axial pure electromagnetic magnetic levitation bearings. Figure 1 Taking the structure shown as an example, the principle of thrust test in the real-time test method of lift-to-drag ratio of solar-powered UAV is explained as follows.

[0078] like Figure 1 As shown, the outer diameter of the rotor shaft is r0, the outer diameter of the stator inner ring is r1, the inner diameter of the inner ring is r2, the inner diameter of the outer ring is r3, the outer diameter of the outer ring is r4, the single-sided air gap length is g, the thickness of the thrust plate is h1, the axial length of the winding slot is h2, and the axial thickness of the winding pole top is h3. In addition, the number of coil turns is N, μ0 is the vacuum permeability, μ r is the relative magnetic permeability of the core, and m1 is the mass of the rotor system. Assume that the displacement of the rotor shaft along the positive x-axis is Δg, the current in the coil in the positive x-axis is i1, and the current in the coil in the negative x-axis is i2.

[0079] Figure 2a and Figure 2b Schematic diagrams of magnetic circuit area division and equivalent magnetic circuit according to an embodiment of the present invention are respectively shown.

[0080] Taking the positive side of the x-axis as an example, the magnetic circuit of the axial magnetic bearing is divided into several different parts (ignoring magnetic leakage). The two-dimensional cross-sectional diagram is shown as follows: Figure 2aAs shown (circular ring structure, so only the symmetrical part in the cross section is shown). Region 1 includes the transition region at the top of the inner magnetic pole, the air gap corresponding to the inner magnetic pole, and the transition region in the thrust disk corresponding to the inner magnetic pole. Region 3 includes the transition region at the top of the outer magnetic pole, the air gap corresponding to the outer magnetic pole, and the transition region in the thrust disk corresponding to the outer magnetic pole. In these two regions, the magnetic lines of force in the transition region are distributed radially, while the magnetic lines of force in the air gap are parallel to the axial direction; Region 2 is the part of the thrust disk excluding Region 1 and Region 3, and Region 5 is the part of the stator corresponding to Region 2. The magnetic lines of force in Region 2 and Region 5 are both parallel to the radial direction; Region 4 is the part of the stator inner ring excluding Region 1, and Region 6 is the part of the stator outer ring excluding Region 3. The magnetic lines of force in these two regions are both parallel to the axial direction. The equivalent magnetic resistance corresponding to each region is R1, R2, R3, R4, R5, and R6 respectively:

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] The equivalent magnetic circuit model is a simple series model. The equivalent magnetic circuit diagram is as follows: Figure 2b As shown. Obviously, the total magnetic resistance R in the magnetic circuit is

[0088]

[0089] Therefore, the suction force F generated by the magnetic bearing on the positive side of the x-axis x The mathematical model can be obtained by formula (1).

[0090] The only difference between the air gap size and coil current on the negative side of the x-axis and the positive side of the x-axis is that F -x Assume that the forward acceleration of the solar drone is a x , from the force analysis of the rotor system, it can be seen that the reasonable size of the magnetic force generated by the magnetic bearing in this state is as shown in formula (3).

[0091] Assuming that the solar drone has n propulsion systems, the electromagnetic forces generated by the magnetic bearings can be calculated using the above principle to be F1 to F2. n .

[0092] A simple force analysis shows that the thrust of the solar drone is equal to the resultant thrust of the propulsion system, as shown in formula (4).

[0093] Assume that the mass of the solar drone is m, the gravity is G, and the corresponding upward acceleration is a z The lift of the solar drone can be calculated as shown in formula (5), and the drag of the solar drone can be calculated as shown in formula (6). Finally, the lift-to-drag ratio of the solar drone can be obtained by formula (7).

[0094] From the above analysis, we can see that most parameters have fixed values, while the only variables that change during flight are the magnetic bearing air gap length, coil current, and acceleration. These parameters can all be acquired and calculated in real time during flight. Therefore, the described method for real-time lift-to-drag ratio testing of solar-powered drones is both clear in principle and feasible.

[0095] Most of the independent variables required for lift-to-drag ratio calculation (modeling) in this method are known; only parameters such as air gap length, coil current, and acceleration require real-time measurement. All parameter measurements and solutions are performed by the drone's existing onboard equipment, eliminating the need for additional equipment.

[0096] The present invention also provides an electronic device, which includes: a memory storing executable instructions; and a processor running the executable instructions in the memory to implement the above-mentioned solar-powered UAV lift-to-drag ratio real-time testing method.

[0097] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the above-mentioned solar-powered UAV lift-to-drag ratio real-time testing method is implemented.

[0098] To facilitate understanding of the solutions and effects of the embodiments of the present invention, three specific application examples are given below. Those skilled in the art should understand that these examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0099] Example 1

[0100] Figure 3 A flow chart showing the steps of a real-time test method for lift-to-drag ratio of a solar-powered UAV according to the present invention.

[0101] like Figure 3As shown, the real-time test method for the lift-to-drag ratio of a solar-powered UAV includes: step 101, establishing an axial single-sided equivalent magnetic circuit model of the solar-powered UAV and calculating the total magnetic resistance of the magnetic circuit; step 102, calculating the magnetic resultant force generated by the magnetic levitation bearing based on the total magnetic resistance; step 103, calculating the thrust of the solar-powered UAV based on the magnetic resultant force generated by the magnetic levitation bearing of each propulsion system; step 104, calculating the lift and drag of the solar-powered UAV, and then calculating the lift-to-drag ratio.

[0102] by Figure 4 The solar drone shown in the figure shows that axial magnetic bearings are still Figure 1 Taking the bearing shown in the figure as an example, the parameter assignments are shown in Table 1 below.

[0103] Table 1

[0104]

[0105]

[0106] According to the above principle, the equivalent magnetic resistance corresponding to each area can be obtained as follows:

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113] The equivalent magnetic circuit model is a simple series model. The equivalent magnetic circuit diagram is as follows: Figure 2b As shown. Obviously, the total magnetic resistance in the magnetic circuit

[0114] Therefore, the suction force generated by the magnetic bearing on the positive side of the x-axis

[0115]

[0116] The only difference between the air gap size and the current size on the negative side of the x-axis and the positive side of the x-axis is that the F -x =497N. Assume that the drone's current forward acceleration ax is 0.8m / s, the longitudinal acceleration a is 0.1m / s, and the drone weighs about 500kg. In this state, the magnetic force generated by the magnetic bearing is F = F -x -F x +m1a x=184N.

[0117] Assuming that the solar drone has three propulsion systems and the parameters of each propulsion system are the same, the thrust of the drone can be calculated as follows: Based on the above assumptions, the lift force F of the solar drone can be obtained: f =ma z +G=4950N, the drag force F of the solar drone r =F t -ma x =152N, then the lift-to-drag ratio of the solar drone is K=F f / F r =32.6.

[0118] In actual applications, the air gap length change Δg, the coil current size i1 of the positive part of x, and the coil current size i2 of the negative part of x are obtained by the solar drone magnetic bearing control system and transmitted to the flight control computer in real time according to the prescribed protocol. The flight control computer integrates the solar drone's flight speed, acceleration and other parameters to complete the real-time calculation and storage of the lift-to-drag ratio.

[0119] Example 2

[0120] The present disclosure provides an electronic device comprising: a memory storing executable instructions; and a processor executing the executable instructions in the memory to implement the aforementioned method for real-time lift-to-drag ratio testing of a solar-powered drone. It should be noted that only the device's composition, functions, and implementation are required; integration with onboard equipment is not excluded.

[0121] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0122] The memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), a hard disk, flash memory, etc.

[0123] The processor may be a central processing unit (CPU) or other form of processing unit having data processing capability and / or instruction execution capability, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to execute the computer-readable instructions stored in the memory.

[0124] Those skilled in the art should understand that in order to solve the technical problem of how to obtain a good user experience, this embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the scope of protection of this disclosure.

[0125] For detailed description of this embodiment, please refer to the corresponding description in the aforementioned embodiments, which will not be repeated here.

[0126] Example 3

[0127] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the real-time test method for the lift-to-drag ratio of a solar-powered UAV is implemented.

[0128] According to an embodiment of the present disclosure, a computer-readable storage medium stores non-transitory computer-readable instructions, which, when executed by a processor, execute all or part of the steps of the aforementioned methods of the embodiments of the present disclosure.

[0129] The above-mentioned computer-readable storage media include, but are not limited to, optical storage media (e.g., CD-ROMs and DVDs), magneto-optical storage media (e.g., MOs), magnetic storage media (e.g., magnetic tapes or mobile hard disks), media with built-in rewritable non-volatile memory (e.g., memory cards), and media with built-in ROM (e.g., ROM cartridges).

[0130] Those skilled in the art should understand that the above description of the embodiments of the present invention is only for the purpose of illustrative purposes only to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0131] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A real-time test method for lift-to-drag ratio of a solar-powered UAV, characterized in that: include: Establish an axial single-sided equivalent magnetic circuit model for a solar drone and calculate the total magnetic resistance of the magnetic circuit; Calculating the resultant magnetic force generated by the magnetic bearing according to the total magnetic resistance; Calculating the thrust of the solar drone based on the resultant magnetic force generated by the magnetic bearings of each propulsion system; Calculating the lift and drag of the solar-powered drone, and then calculating the lift-to-drag ratio; The calculation of the magnetic force generated by the magnetic bearing includes: Calculate the suction force generated by the magnetic bearings on the positive and negative sides of the x-axis respectively based on the total magnetic resistance; Calculate the magnetic force generated by the magnetic bearing according to the suction force generated by the magnetic bearing on the positive and negative sides of the x-axis; The suction force generated by the magnetic bearing on the positive side of the x-axis is calculated using formula (1): Among them, F x is the suction force generated by the magnetic bearing on the positive side of the x-axis, R is the total magnetic resistance, r1, r2, r3, and r4 are the inner ring outer diameter, inner ring inner diameter, outer ring inner diameter, and outer ring outer diameter of the stator respectively, N is the number of coil turns, μ0 is the vacuum permeability, and i1 is the current of the coil in the positive direction of x-axis; The suction force generated by the magnetic bearing on the negative side of the x-axis is calculated using formula (2): Among them, F -x is the suction force generated by the magnetic bearing on the negative side of the x-axis, and i2 is the current of the coil on the negative side of the x-axis; The magnetic force generated by the magnetic bearing is calculated by formula (3): F=F -x -F x +m1a x (3) Where F is the magnetic force generated by the magnetic bearing, and m1 is the mass of the rotor system.

2. The real-time test method for lift-to-drag ratio of a solar-powered UAV according to claim 1, wherein: The thrust of the solar drone is calculated by formula (4): Among them, F t is the thrust of the solar drone, F j is the resultant magnetic force generated by the magnetic bearings of the j-th propulsion system, and n is the number of propulsion systems.

3. The real-time test method for lift-to-drag ratio of a solar-powered UAV according to claim 2, wherein: The lift of the solar drone is calculated by formula (5): F f =at z +G (5) The resistance of the solar drone is calculated by formula (6): F r =F t -ma x (6) Among them, F f is the lift, F r is the resistance, m is the mass of the solar drone, G is the gravity of the solar drone, a z is the upward acceleration at the current moment.

4. The real-time test method for lift-to-drag ratio of a solar-powered UAV according to claim 3, wherein: The lift-to-drag ratio is calculated using formula (7): K=F f F r (7) Where K is the lift-to-drag ratio.

5. An electronic device, characterized in that: The electronic device comprises: a memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the real-time test method for the lift-to-drag ratio of a solar-powered unmanned aerial vehicle according to any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the real-time test method for the lift-to-drag ratio of a solar-powered unmanned aerial vehicle according to any one of claims 1 to 4.

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