Autorotation combined type solar unmanned aerial vehicle and design method

Abstract

The invention discloses an autorotation combined type solar unmanned aerial vehicle and a design method, and belongs to the technical field of solar unmanned aerial vehicles. The unmanned aerial vehicle lift force system is composed of the wing modules and the autorotation rotor wing modules, the autorotation rotor wing modules do not need extra energy input, lift force is generated through incoming flow driving, and energy loss is remarkably reduced through cooperation of the foldable thrust propellers and the V-shaped empennages. The invention further provides a rapid design method matched with the unmanned aerial vehicle, total parameters are determined through iterative optimization based on the principles of energy balance, force balance and power balance, and it is guaranteed that the unmanned aerial vehicle can still achieve long-endurance flight under the condition that the photovoltaic intensity is weakest. The unmanned aerial vehicle solves the problems that a traditional solar unmanned aerial vehicle is weak in overnight capability, limited in take-off and landing, large in energy loss and the like, and is suitable for long-endurance task execution and test flight verification.

Description

Technical Field

[0001] This invention belongs to the field of solar-powered drones, and more specifically, relates to a self-rotating composite solar-powered drone and its design method. Background Technology

[0002] Solar-powered unmanned aerial vehicles (UAVs), as long-endurance aircraft that use solar energy as their core energy source, have broad application prospects in fields such as reconnaissance and surveillance, communication relay, and environmental detection due to their advantages such as zero emissions and strong continuous operation capabilities. Their core design logic involves collecting solar energy through solar cells and converting it into electrical energy to power the propulsion system and onboard equipment, while relying on the lift generated by the wings to maintain flight and achieve long-term aerial deployment.

[0003] However, existing solar-powered drones still suffer from many insurmountable technical defects in practical applications, which severely limit their applicability and operational reliability, as follows: Low energy efficiency and significant energy consumption pressure: Conventional solar-powered drones rely entirely on their wings for lift, and sufficient lift requires a power system to drive the propellers to maintain high-speed flight. This places extremely high demands on the power system's power output and the energy storage capacity of the energy system. Simultaneously, existing designs lack effective wind energy utilization mechanisms, failing to convert high-altitude airflow into auxiliary lift, resulting in high propulsion energy loss. This necessitates the use of large-capacity energy storage batteries and large-area photovoltaic cells, directly increasing the fuselage weight and reducing flight maneuverability. More critically, at night when there is no solar power supply, drones must actively descent to reduce energy consumption. However, as the altitude decreases during descent, they are highly susceptible to entering low-altitude wind layers, leading to drone backflight. The lower the altitude, the greater the backflight distance, not only deviating from the mission area but also requiring significant energy consumption to climb back to the target altitude for photovoltaic recharging after sunrise the following day, further exacerbating the energy supply and demand imbalance.

[0004] Limited nighttime flight capability and high survival risk: Existing solar-powered drones have low service ceilings and high descent rates, limiting their altitude for nighttime flight. During nighttime descent, drones are prone to getting caught in complex low-altitude weather environments (such as turbulence and gusts), which not only increases the difficulty of operation for flight operators but may also cause structural damage due to airflow disturbances. At the same time, strong airflow in the low-altitude wind layer can further amplify the retreat effect, making it impossible for the drone to maintain its mission in a fixed area, or even to complete its climb due to energy depletion, leading to a risk of crash.

[0005] Poor flexibility in takeoff and landing and deployment, and high operating costs: Traditional solar-powered drones mostly adopt an integrated structural design, resulting in a bulky fuselage that cannot be quickly disassembled. Transportation and storage require specialized equipment, making it difficult to adapt to the rapid deployment needs of complex scenarios such as the field and emergency situations. In addition, existing designs generally rely on landing gear systems and dedicated runways for takeoff and landing, which places stringent requirements on site conditions and cannot operate on unpaved surfaces such as grass and dirt roads, limiting their application in remote areas and temporary mission sites. Furthermore, the assembly process is complex, often requiring multiple people to collaborate and use tools, resulting in low deployment efficiency.

[0006] Insufficient flight safety and low fault tolerance: Existing solar-powered drones lack an effective emergency lift guarantee mechanism. When the power system fails or the energy is exhausted, they cannot reduce the descent speed through structural adjustments and can only rely on gliding landing. The high descent rate results in a large landing impact load, which can easily cause damage to the fuselage or airborne equipment, seriously affecting mission continuity and equipment reusability.

[0007] To address the aforementioned technical shortcomings, there is an urgent need for a solar-powered unmanned aerial vehicle (UAV) configuration that can efficiently utilize wind energy, reduce energy consumption, enhance nighttime flight capabilities, and improve deployment flexibility. A self-rotating rotor requires no additional energy input; it generates lift solely from the forward-flowing component, effectively compensating for the lift supply limitations of existing designs. Furthermore, its modular design allows for rapid disassembly and assembly of the fuselage, improving deployment convenience. Based on this, this invention proposes a self-rotating hybrid solar-powered UAV and its design method, aiming to specifically address the core pain points of existing technologies, expand the application scenarios of solar-powered UAVs, and improve their operational reliability. Summary of the Invention

[0008] The purpose of this invention is to provide a self-rotating composite solar-powered drone that solves the problems of inefficient wind energy utilization, high energy consumption, poor night-crossing capability, and poor deployment flexibility of existing drones.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a self-rotating composite solar-powered unmanned aerial vehicle, comprising: fuselage module; A pair of wing modules are connected to both sides of the fuselage module; The autorotor module includes an autorotor shaft, a pre-cone mechanism, and autorotor blades. The autorotor blades are connected to the autorotor shaft via the pre-cone mechanism. The autorotor shaft is vertically connected to the top of the fuselage module. The pre-cone mechanism can adjust the pre-cone angle of the autorotor blades. The autorotor blades generate a driving force through the forward flow component, thereby achieving autorotation and outputting lift. Tail fin module, connected to the rear of the fuselage module; The power module includes a thrust propeller and a motor. The thrust propeller is located at the head of the fuselage module, and the motor is connected to the thrust propeller in a transmission manner. Solar cells are laid on the upper surface of the wing module.

[0010] Optionally, the wing module includes a winglet, an anhedral wing, and an aileron. One end of the anhedral wing is connected to the fuselage module, the winglet is connected to the other end of the anhedral wing, and the aileron is located at the rear of the anhedral wing.

[0011] Optionally, the tail module includes a V-shaped tail and tail control surfaces, the V-shaped tail being fixed to the rear of the fuselage module, and the tail control surfaces being disposed at the rear of the V-shaped tail.

[0012] Optionally, the wing module, the autorotor module, and the tail module are all detachably connected to the fuselage module; The thrust propeller has foldable blades and is set close to the fuselage module when not in operation.

[0013] Secondly, the present invention provides a design method for a self-rotating composite solar-powered unmanned aerial vehicle (UAV), applicable to the UAV described in the first aspect, comprising the following steps: S1, the design time point is selected when the local photovoltaic intensity is weakest, that is, the summer solstice in the Southern Hemisphere or the winter solstice in the Northern Hemisphere; S2, Given initial parameters, the initial parameters include: the initial weight of the UAV. Latitude value of the flight location Initial value of lift-to-drag ratio Wing design span Air density at different altitudes wing initial aspect ratio Rotor blade radius ; S3 calculates the weight of each component and the total weight of the UAV based on energy balance, force balance, and power balance. ,Will With initial weight Compare the differences and iteratively adjust the design parameters until the preset weight error requirement is met; S4 uses eddy current theory to design a thrust propeller and conventional design methods to design the fuselage module, tail module, and wing module to obtain the final design parameters.

[0014] Optionally, in step S2, the initial value of the boost-to-drag ratio is... The value range is 20~30; Initial aspect ratio of wing module The value range is 15 to 30.

[0015] Optionally, step S3 includes the following sub-steps: S3.1, Input the design pull force of the autorotator module Number of blades Rotor speed Air density at different altitudes Calculate the incoming flow velocity Determine the airfoil distribution and lift-drag coefficient, solve for the aerodynamic parameters, and obtain the lift at different altitudes. and ; S3.2, the lift-drag coefficient of the airfoil is calculated using aerodynamic design software. Calculate the overall drag coefficient based on force balance. Daytime cruising speed and nighttime cruising speed ; S3.3, determine the time and power consumption of each flight phase, obtain the energy consumption and other energy consumption of the flight phase, establish the energy balance relationship, and solve for the energy of the energy storage battery. and solar cell energy consumption ; S3.4 Calculate the weight of each component separately and sum them to obtain the total weight of the entire machine. ; S3.5, Calculation With initial weight If the relative error does not meet the preset requirements, adjust the initial parameters or design variables, and repeat steps S3.1 to S3.4 until the error meets the standard.

[0016] Optionally, in step S3.1, the tension is designed. ; Incoming flow velocity Through formula Calculation, where To design the monthly average airflow velocity at the height, For the pre-cone angle of the autorotator, This refers to the cruise attitude angle.

[0017] Optionally, in step S3.2, the daytime cruising speed... The calculation formula is:

[0018] Nighttime cruising speed The calculation formula is:

[0019] In the formula, The lift generated by the wing module, The lift generated by the autorotor module, For the overall drag of the machine, The projected area of ​​the anhedral wing. For the lift generated by the daytime autorotor module, The air density at different altitudes corresponds to the lift generated by the autorotator module at night. There are differences.

[0020] Optionally, in step S4, the design of the thrust propeller includes the following sub-steps: S4.1, given axial flow velocity propeller blade radius Paddle leaf root cut propeller rotation speed Number of blades and leaf string length ; S4.2, split the propeller into Segment, calculate 0.7 Mach number at Select a propeller airfoil and use airfoil design software to calculate the lift coefficient of the airfoil at various angles of attack. and drag coefficient Select the optimal angle of attack for each segment. ; S4.3, the optimal angle of attack method is used to calculate the installation angle of each blade element of the propeller. ,satisfy ,in The rate of leaf lin induction; S4.4, Calculate the leaf element tension coefficient and torque coefficient Solve for the total aerodynamic force of the propeller until the calculated thrust equals the required thrust.

[0021] The self-rotating composite solar-powered UAV and its design method of the present invention have the following beneficial effects: 1. High energy efficiency: The autorotor does not require additional energy input. It generates lift by being driven by the airflow, which reduces power consumption and the weight of energy storage batteries and photovoltaic cells. The weight saved can be used to enhance the overall structural strength of the aircraft and improve its wind resistance and survivability. 2. Highly convenient to deploy: The modular design enables rapid disassembly and assembly of the entire aircraft. With the foldable propeller, it is easy to carry and transport. Assembly can be completed by 2-3 people. Four people can lift and run to take off or glide from a vehicle. There are no site restrictions. The soft landing of the glider does not require landing gear, making take-off and landing convenient. 3. Superior night-flying capability and safety: The autorotating composite configuration enables the drone to have a higher climb rate and a lower glide rate than conventional solar-powered drones, improving its service ceiling and night-flying altitude, avoiding glide into the wind layer and complex low-altitude weather, and reducing the retreat distance; in the event of power loss, the autorotating rotor can reduce the glide speed, achieving a low-impact landing and improving flight safety. 4. Scientific and efficient design methodology: Based on the principles of energy, force and power balance, combined with the characteristics of the autorotor, the overall parameters are determined through iterative optimization, adapting to the weakest photovoltaic intensity conditions, ensuring long-endurance flight requirements, and the design process is standardized, which can quickly output the optimal parameters to meet the needs of mass production and customization of UAVs.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0024] Figure 1 One of the schematic structural diagrams of a self-rotating composite solar-powered unmanned aerial vehicle according to Embodiment 1 of the present invention is shown.

[0025] Figure 2 The second schematic structural diagram of a self-rotating composite solar-powered unmanned aerial vehicle according to Embodiment 1 of the present invention is shown.

[0026] Figure 3 The third schematic structural diagram of a self-rotating composite solar-powered unmanned aerial vehicle according to Embodiment 1 of the present invention is shown.

[0027] Figure 4 A cross-sectional view of a self-rotating composite solar-powered unmanned aerial vehicle (UAV) flight mission according to Embodiment 2 of the present invention is shown.

[0028] Figure 5 A flowchart illustrating the design method of a self-rotating composite solar-powered unmanned aerial vehicle according to Embodiment 2 of the present invention is shown.

[0029] Explanation of reference numerals in the attached figures: 1. Fuselage module; 2. Wing module; 21. Winglet; 22. Anhedral wing; 23. Aileron; 3. Rotor module; 31. Rotor shaft; 32. Pre-cone mechanism; 33. Rotor blades; 4. Tail fin module; 41. V-tail fin; 42. Tail fin control surfaces; 5. Power module; 51. Thrust propeller; 52. Motor; 6. Photoelectric load. Detailed Implementation

[0030] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0031] Example 1

[0032] like Figure 1-3 As shown, this embodiment provides a self-rotating composite solar-powered unmanned aerial vehicle, including: The fuselage module 1 contains the flight control, navigation, and airborne equipment, and the optoelectronic payload 6 is located below it. The fuselage module 1 provides the installation foundation for other modules. The flight control and navigation system realizes flight status monitoring and control, and the optoelectronic payload 6 is used to perform reconnaissance, monitoring, and other tasks.

[0033] A pair of wing modules 2 are connected to both sides of the fuselage module 1; The autorotor module 3 includes an autorotor shaft 31, a pre-cone mechanism 32, and an autorotor blade 33. The autorotor blade 33 is connected to the autorotor shaft 31 through the pre-cone mechanism 32. The autorotor shaft 31 is vertically connected to the top of the fuselage module 1. The pre-cone mechanism 32 can adjust the pre-cone angle of the autorotor blade 33. The autorotor blade 33 generates a driving force through the component of the forward flow, realizes autorotation, and outputs lift. The pre-cone angle of the pre-cone mechanism 32 can be adjusted within the range of 8~15° to adapt to different flight conditions. Tail wing module 4 is connected to the tail of fuselage module 1; The power module 5 includes a thrust propeller 51 and a motor 52. The thrust propeller 51 is located at the head of the fuselage module 1, and the motor 52 is connected to the thrust propeller 51 in a transmission. Solar cells are laid on the upper surface of wing module 2 to maximize the use of sunlight for photoelectric conversion.

[0034] The drone is designed without landing gear and takes off with a manual lift-up run, requiring no dedicated runway and having no site restrictions. When landing, it adopts a gliding soft landing method, relying on the lift generated by the autorotator to reduce the descent speed and reduce the impact load.

[0035] Specifically, the system employs a composite lift configuration of wing module 2 and autorotor module 3. The autorotor module 3 requires no additional energy input, generating lift solely through forward airflow, significantly reducing power system energy consumption and the weight of energy storage batteries and solar panels. The saved weight can be used to enhance the overall structural strength, improving wind resistance and survivability. Simultaneously, the presence of the autorotor module 3 allows the UAV to have a higher climb rate and a lower glide rate, enabling it to fly at higher altitudes. This increases both the service ceiling and the overnight altitude, reducing damage from glide into high winds and avoiding complex low-altitude weather conditions. It also reduces the operational difficulty for pilots in complex airflow environments and decreases the retreat distance, allowing the UAV to perform missions in relatively fixed areas. Furthermore, the UAV offers a degree of safety; even in the event of power loss, it can rely on the forward airflow to autorotate the rotor, reducing glide speed and achieving a low glide rate landing, thus mitigating damage to the solar-powered UAV to some extent.

[0036] Optionally, the wing module 2 includes a winglet 21, an anti-dipping wing 22, and an aileron 23. One end of the anti-dipping wing 22 is connected to the fuselage module 1, the winglet 21 is connected to the other end of the anti-dipping wing 22, and the aileron 23 is located at the rear of the anti-dipping wing 22.

[0037] Specifically, the winglet 21 can effectively suppress vortex loss at the wingtip, reduce induced drag, improve wing aerodynamic efficiency, and reduce energy consumption; the anhedral wing 22 can enhance the lateral stability of the UAV, avoid roll caused by airflow disturbance during flight, and adapt to complex airflow environments at high altitudes; the aileron 23 is arranged at the rear of the anhedral wing, which can precisely adjust the lift distribution of the wing, realize the roll attitude control of the UAV, improve flight maneuverability, and facilitate mission execution in fixed areas.

[0038] Optionally, the tail module 4 includes a V-tail 41 and a tail control surface 42. The V-tail 41 is fixed to the tail of the fuselage module 1, and the tail control surface 42 is located at the rear of the V-tail 41. The flight attitude control of the UAV is achieved by deflecting the tail control surface 42.

[0039] Specifically, the V-tail 41 functions as both a rudder and an elevator. Compared to traditional split tails, it has a more compact structure, which can reduce flight drag and fuselage weight, and improve energy efficiency. The tail control surface 42 is located at the rear of the V-tail 41 and can precisely control the pitch and heading attitude of the UAV by deflection, thereby enhancing flight stability and control precision and reducing the difficulty of operation in complex airflow environments.

[0040] Optionally, the wing module 2, the autorotor module 3, and the tail module 4 are all detachably connected to the fuselage module 1; The thrust propeller 51 has foldable blades. When not in operation, it is set close to the fuselage module 1 to achieve integrated transportation and assembly with the fuselage. When in operation, it unfolds to generate forward thrust.

[0041] Specifically, the wing module 2, rotor module 3, and tail module 4 are detachably connected to the fuselage module 1, enabling modular disassembly of the entire aircraft. This facilitates transportation and storage, reduces carrying difficulty, and meets the needs of rapid deployment. The thrust propeller 51 features a foldable design, fitting snugly against the fuselage when not in operation, minimizing space occupation during transportation and achieving integrated transport with the fuselage. It also prevents blade damage from impacts, improving equipment durability. The modular design, combined with the foldable propeller, eliminates the need for dedicated storage and transportation equipment, adapting to rapid deployment in various scenarios such as field operations and emergency situations, enhancing ease of use. Takeoff requires only four people to provide a running start, with no site restrictions. Landing utilizes a gliding landing, facilitating convenient takeoff and landing. This drone is a high-wing loading type with strong structural strength, representing an important means to reduce energy loss and improve nighttime flight altitude and safety.

[0042] The method of using the drone in this embodiment is as follows: Ground assembly: 2-3 people can complete the modular assembly of each module without the need for complicated tools; Takeoff: Takeoff is achieved by vehicle-mounted gliding or by a 4-person lift-off run. The thrust propeller 51 generates forward force, and the wings and autorotors together generate lift. As the forward speed increases, the proportion of lift generated by the autorotors increases, while the proportion of lift generated by the wings decreases. Flight adjustment: After climbing to the daytime cruise altitude, reduce the speed of the thrust propeller 51 and increase the pre-cone angle of the autorotor, and the UAV enters the horizontal cruise state; when solar energy is insufficient, the UAV will descend to the night cruise altitude without power, activate the low energy consumption mode, and maintain the altitude through the operating condition matching of the thrust propeller 51 autorotor to conduct night cruise. Landing: After the mission is completed, glide to a flat surface such as grass or hard dirt road, and rely on the low glide rate to reduce the impact load and achieve a safe landing.

[0043] Example 2

[0044] This embodiment provides a design method for a self-rotating hybrid solar-powered unmanned aerial vehicle (UAV), applicable to the UAV of Embodiment 1, whose mission profile is as follows. Figure 5 As shown, the flight path is divided into the climb phase, the daytime cruise phase, the descent phase, and the nighttime cruise phase, which are repeated in a cycle until the mission is completed and the flight enters the descent and landing phase.

[0045] like Figure 4 As shown, the design method of this embodiment includes the following steps: S1. Select the design time point. Considering that solar-powered drones rely on solar power, in order to ensure flight performance under extreme conditions, the design time point is selected as the time when the local photovoltaic intensity is weakest, that is, the summer solstice in the Southern Hemisphere or the winter solstice in the Northern Hemisphere. S2, Input initial parameters, including: initial weight of the drone. Initial values ​​can be estimated through experience or preset; latitude value of the flight location Initial value of lift-to-drag ratio The value ranges from 20 to 30; wing design span Designed according to design requirements and relevant standards of "Overall Design of Unmanned Aerial Vehicles"; air density at different altitudes ; Initial aspect ratio of the wing The value ranges from 15 to 30; the radius of the autorotator. The design is based on the rotor disk area and rotor solidity range, with reference to the "Helicopter Design Manual" and related autogyro rotor design literature. S3 calculates the weight of each component and the total weight of the UAV based on energy balance, force balance, and power balance. ,Will With initial weight Perform difference comparisons and iteratively adjust design parameters until the preset weight error requirement is met; this includes the following sub-steps: S3.1, Autorotor Design: The autorotor provides lift only. The design is based on momentum-blade element theory and vortex theory. Specific steps: a. Input design tensile force Number of blades Rotor speed Blade radius Paddle leaf root cut Air density at different altitudes Design tension , The value range is 0.3~0.8; incoming flow velocity ,in, The axial velocity is the average monthly average airflow velocity at the design altitude. Pre-cone angle of the autorotator; The cruise attitude angle is typically taken as 0°; the rotor speed... and blade radius The design was based on the Aerodynamic Design Manual and the Helicopter Design Manual; the design point was the daytime cruising altitude.

[0046] b. Blade element splitting and parameter input: Divide the rotor blades into n blade elements, determine the airfoil distribution at each section, and input the optimal angle of attack for each section. and the corresponding lift coefficient , ; c. Solving for the Lagrange multiplier The relevant calculation formulas are as follows:

[0047] In the formula, dr and dr are the radius and length of the blade element, respectively; γ is the blade tip ratio, which is the ratio of the chord length at the blade tip to the chord length at the blade root, and affects the rotor aerodynamic efficiency. The initial value of the boost-to-drag ratio is consistent with the input parameters in step S2. These are parameters derived from the Lagrange multiplier. The induced velocity component at the leaf element.

[0048] d. Calculate the transformation angle , inducing angle of attack and leaf string length The formula is as follows:

[0049] In the formula, The forward ratio reflects the ratio of the incoming flow velocity to the rotor circumferential velocity; Let be the radial coordinate value of the i-th blade element, which is the distance along the blade radius direction with the rotor shaft as the origin; This is the initial value for the lift-to-drag ratio; , These are the lift coefficient and drag coefficient of the blade element section, respectively.

[0050] e. Calculate the leaf element installation angle : Solving the induced velocity using momentum-leaf element theory and the angle of flow The relevant formulas are as follows:

[0051] Then through The installation angle was calculated to obtain the aerodynamic shape parameters of the autorotor. The design was completed using 3D modeling software, and the algebraic formulas for calculating the aerodynamic lift of the rotor at different heights and key parameters such as the autorotor radius were derived based on these parameters. Induced velocity. It is the downward airflow velocity generated when the rotor rotates, which affects the lift distribution of the blades. It is solved iteratively using the momentum-blade element theory. , The drag coefficients of the leaf element in the kth segment are respectively (and , Consistent).

[0052] S3.2, Calculation of Airfoil Aerodynamic Coefficients and Flight Speed: The aerodynamic coefficients of the selected airfoil are calculated using the aerodynamic design software Xflr. The lift and drag coefficients of the airfoil are iterated under cruise conditions, and the lift coefficient of the airfoil is obtained through three-dimensional aerodynamic analysis. Then, the overall drag coefficient is calculated based on the force balance. Daytime cruising speed and nighttime cruising speed ; Daytime cruising speed The calculation formula is:

[0053] Nighttime cruising speed The calculation formula is:

[0054] In the formula, The lift generated by the wings The lift generated by the autorotating rotor For the overall drag of the machine, Wing area For the lift generated by the daytime rotating rotor, The air density at different altitudes corresponds to the lift generated by the rotating rotor at night. There are differences.

[0055] S3.3, Energy Consumption Calculation: Determine the time and power consumption of each flight phase, obtain the energy consumption of the flight phase and other energy consumption, establish the energy balance relationship, and solve for the energy of the energy storage battery. and solar cell energy consumption The specific steps are as follows: a. Flight phase time determination: Local sunrise time is used as the start time for ascent, and sunset time is used as the start time for descent. Ascent time and descent time The calculation formula is as follows:

[0056] In the formula, The climb and descent altitudes are equal to the design maximum service ceiling minus the design nighttime cruising altitude, as specified in the design requirements. and These represent the drone's climb rate and descent rate, values ​​chosen empirically. This drone has a lower descent rate and a higher climb rate than conventional solar-powered drones. The daytime cruise time is then derived by combining the total sunrise and sunset durations. and nighttime cruise time .

[0057] b. Power calculation for each stage: Rise Power ; Daytime cruise power ; Downward Power ; Nighttime cruise power ; In the formula, To improve efficiency, the value ranges from 0.80 to 0.90, reflecting the efficiency of the motor 52-propeller system in converting electrical energy into thrust, based on measured data of existing aerospace-grade brushless motor 52 and propeller. This refers to the forward flight speed during ascent; This is the initial value for the lift-to-drag ratio.

[0058] c. Energy consumption calculation: S3.4, component weight estimation: calculate the weight of components such as energy storage battery, wings, fuselage, and autorotor separately, and sum them to obtain the total weight of the entire aircraft. ; The energy consumption during the flight phase is calculated using the following formula: ; ; Calculate other energy consumption, including power consumption of the load during the day and night. and the energy consumption of airborne equipment (Daytime) and (at night); Energy balance relationship: Energy of energy storage battery Solar cell energy consumption .

[0059] S3.5, Calculation With initial weight If the relative error does not meet the preset requirements, adjust the initial parameters or design variables, and repeat steps S3.1 to S3.4 until the error meets the standard.

[0060] The calculation specifically includes: Energy storage battery weight: , Energy density of energy storage batteries, expressed in Wh / kg; Wing weight: , The adjustment coefficient is related to the unmanned structure and materials, and is based on statistical data of similar unmanned aerial vehicles. Body weight: , This is an adjustment coefficient, which is related to the unmanned structure and materials. The wetted area of ​​the fuselage, i.e. the total area of ​​the fuselage in contact with the air, is calculated using 3D modeling software; The aspect ratio is the ratio of the fuselage length to the maximum cross-sectional diameter. Rotor weight: , The solidity of the autorotor is the ratio of the total blade area to the disk area. The rotor disk load is the ratio of the total thrust of the autorotating rotor to the area of ​​the rotor disk. The adjustment coefficient is related to the rotor blade material and hub structure; The thrust generated by the rotating rotor; Solar cell weight: , The density of the solar cell array; The area of ​​the solar cell wafer. This represents the photoelectric conversion energy per unit area of ​​the solar cell, and its value is based on the solar radiation flux when the local photovoltaic intensity is weakest. Photoelectric conversion efficiency; The efficiency loss of the solar cell array includes losses due to cell series connection and temperature loss. For power controller efficiency.

[0061] Power controller weight: , The power-to-weight ratio of the power controller; Propulsion system weight: , To improve the system's power-to-weight ratio, based on the existing 52 brushless DC motor technology level; This refers to the propulsion system power during climb. Airborne cable weight: ; Total weight of the aircraft: , This refers to the load weight; The iterative optimization specifically involves: calculating the total weight of the entire machine. With initial weight The difference calculation was performed, and the design parameters were iteratively adjusted, including the wingspan b, the autorotor radius R, the initial lift-to-drag ratio K, and the pre-cone angle θ of the pre-cone mechanism, until... The final design parameters are output, including the lift-to-drag ratio, weight, cruise speed, aerodynamic parameters of the autorotor, weight of each system, battery capacity, solar cell coverage area, and wing area.

[0062] S4, based on eddy current theory, designed the thrust propeller 51, and used conventional design methods to design the fuselage, tail and wings to obtain the final design parameters.

[0063] The design of the thrust propeller 51 includes the following sub-steps: S4.1, given axial flow velocity propeller blade radius Paddle leaf root cut propeller rotation speed Number of blades and leaf string length ; S4.2, split the propeller into Segment, calculate 0.7 Mach number at Select a propeller airfoil and use Profili software to calculate the lift coefficient of the airfoil at various angles of attack. and drag coefficient Select the optimal angle of attack for each segment. The angle of attack at which the airfoil achieves its maximum lift-to-drag ratio is determined by the aerodynamic characteristic curve of the selected airfoil. S4.3, the optimal angle of attack method is used to calculate the installation angle of each blade element of the propeller. ,satisfy ,in The rate of leaf lin induction; The velocity induced by the leaf element is calculated with reference to "Helicopter Overall Design"; S4.4, Calculate the leaf element tension coefficient and torque coefficient Solve for the total aerodynamic force of the propeller until the calculated thrust equals the required thrust.

[0064] Leaf element tensile coefficient and torque coefficient The calculation formula is: The desired propeller blade element chord length is calculated.

[0065] The formula for calculating the total aerodynamic force of a propeller is:

[0066] Once the calculated thrust equals the required thrust, the chord length of the propeller blade element for each blade element segment can be obtained. The values ​​were then used to obtain the final aerodynamic shape data of the thrust propeller 51.

[0067] Rotor design: Refer to the design process in step S3.1.

[0068] Fuselage, tail, and wing design: The design was carried out using conventional UAV design methods to achieve rapid iterative design of the self-rotating composite solar-powered UAV.

[0069] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they 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 self-rotating composite solar-powered unmanned aerial vehicle, characterized in that, include: Fuselage module (1); A pair of wing modules (2) are connected to both sides of the fuselage module (1); The autorotor module (3) includes an autorotor shaft (31), a pre-cone mechanism (32), and an autorotor blade (33). The autorotor blade (33) is connected to the autorotor shaft (31) through the pre-cone mechanism (32). The autorotor shaft (31) is vertically connected above the fuselage module (1). The pre-cone mechanism (32) can adjust the pre-cone angle of the autorotor blade (33). The autorotor blade (33) generates a driving force through the component of the forward flow, realizes autorotation, and outputs lift. Tail wing module (4) is connected to the tail of the fuselage module (1); The power module (5) includes a thrust propeller (51) and a motor (52). The thrust propeller (51) is located at the head of the fuselage module (1), and the motor (52) is connected to the thrust propeller (51) in a transmission connection. Solar cells are laid on the upper surface of the wing module (2).

2. The self-rotating composite solar-powered UAV according to claim 1, characterized in that, The wing module (2) includes a winglet (21), an anti-dipping wing (22), and an aileron (23). One end of the anti-dipping wing (22) is connected to the fuselage module (1), the winglet (21) is connected to the other end of the anti-dipping wing (22), and the aileron (23) is located at the rear of the anti-dipping wing (22).

3. The self-rotating composite solar-powered UAV according to claim 1, characterized in that, The tail module (4) includes a V-shaped tail (41) and a tail control surface (42). The V-shaped tail (41) is fixed to the tail of the fuselage module (1), and the tail control surface (42) is located at the rear of the V-shaped tail (41).

4. The self-rotating composite solar-powered UAV according to claim 1, characterized in that, The wing module (2), the autorotor module (3) and the tail module (4) are all detachably connected to the fuselage module (1); The thrust propeller (51) has foldable blades and is set close to the fuselage module (1) when not in operation.

5. A design method for a self-rotating composite solar-powered unmanned aerial vehicle (UAV), applicable to the UAV described in claim 1, characterized in that, Includes the following steps: S1, the design time point is selected when the local photovoltaic intensity is weakest, that is, the summer solstice in the Southern Hemisphere or the winter solstice in the Northern Hemisphere; S2, Input initial parameters, including: initial weight of the UAV. Latitude value of the flight location Initial value of lift-to-drag ratio Wing design span Air density at different altitudes wing initial aspect ratio , Radius of the rotating rotor blade (33) ; S3 calculates the weight of each component and the total weight of the UAV based on energy balance, force balance, and power balance. ,Will With initial weight Compare the differences and iteratively adjust the design parameters until the preset weight error requirement is met; S4, based on eddy current theory, designed the thrust propeller (51), and used conventional design methods to design the fuselage module (1), tail module (4) and wing module (2), and output the final design parameters.

6. The design method for a self-rotating composite solar-powered unmanned aerial vehicle according to claim 5, characterized in that, In step S2, the initial value of the boost-to-drag ratio is... The value range is 20~30; Initial aspect ratio of wing module (2) The value range is 15 to 30.

7. The design method for a self-rotating composite solar-powered unmanned aerial vehicle according to claim 5, characterized in that, Step S3 includes the following sub-steps: S3.1, Input the design pull of the self-rotating rotor module (3) Number of blades Rotor speed Air density at different altitudes Calculate the incoming flow velocity Determine the airfoil distribution and lift-drag coefficient, solve for the aerodynamic parameters, and obtain the lift at different altitudes. and ; S3.2, the lift-drag coefficient of the airfoil is calculated using aerodynamic design software. Calculate the overall drag coefficient based on force balance. Daytime cruising speed and nighttime cruising speed ; S3.3, determine the time and power consumption of each flight phase, obtain the energy consumption and other energy consumption of the flight phase, establish the energy balance relationship, and solve for the energy of the energy storage battery. and solar cell energy consumption ; S3.4 Calculate the weight of each component separately and sum them to obtain the total weight of the entire machine. ; S3.5, Calculation With initial weight If the relative error does not meet the preset requirements, adjust the initial parameters or design variables, and repeat steps S3.1 to S3.4 until the error meets the standard.

8. The design method for a self-rotating composite solar-powered unmanned aerial vehicle according to claim 7, characterized in that, In step S3.1, Design tension ; Incoming flow velocity ,in To design the monthly average airflow velocity at the height, For the pre-cone angle of the autorotator, This refers to the cruise attitude angle.

9. The design method for a self-rotating composite solar-powered unmanned aerial vehicle according to claim 7, characterized in that, In step S3.2, Daytime cruising speed The calculation formula is: Nighttime cruising speed The calculation formula is: In the formula, The lift generated by the wing module (2), The lift generated by the autorotor module (3) For the overall drag of the machine, For the area of ​​the anhedral wing (22), The lift generated by the daytime autorotor module (3), The air density at different altitudes corresponds to the lift generated by the nighttime autorotator module (3). There are differences.

10. The design method for a self-rotating composite solar-powered unmanned aerial vehicle according to claim 5, characterized in that, In step S4, the design of the thrust propeller (51) includes the following sub-steps: S4.1, given axial flow velocity propeller blade radius Paddle leaf root cut propeller rotation speed Number of blades and leaf string length ; S4.2, split the propeller into Segment, calculate 0.7 Mach number at Select a propeller airfoil and use airfoil design software to calculate the lift coefficient of the airfoil at various angles of attack. and drag coefficient Select the optimal angle of attack for each segment. ; S4.3, the optimal angle of attack method is used to calculate the installation angle of each blade element of the propeller. ,satisfy ,in The rate of leaf lin induction; S4.4, Calculate the leaf element tension coefficient and torque coefficient Solve for the total aerodynamic force of the propeller until the calculated thrust equals the required thrust.

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