Method for designing configuration of unmanned aerial vehicle flying in wide speed domain

Abstract

The invention discloses a configuration design method for an unmanned aerial vehicle flying in a wide speed domain. The method comprises the following steps: acquiring real-time flight state parameters of the unmanned aerial vehicle; on the basis of a preset pneumatic-structure-environment coupling optimization model, the optimal wing oblique angle matched with the current flight working condition is calculated; a wing driving device is controlled according to the optimal wing inclination angle, and switching of the wing inclination angle is achieved; dynamically sensing the flight state change in the flight process, updating the optimal wing inclination angle in real time, and adjusting the wing attitude; according to the method, the flight state parameters are sensed in real time, the optimal wing inclination angle is dynamically calculated based on the pneumatic-structure-environment coupling optimization model, self-adaptive adjustment of the wing attitude is achieved, and the problems that an existing unmanned aerial vehicle is narrow in speed domain coverage, poor in task adaptability and difficult to consider both stability and structural safety are solved. And the full-speed-domain flight performance and the multi-scene adaptability of the unmanned aerial vehicle are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicle design, in particular to a wide speed domain flight unmanned aerial vehicle type design method. BACKGROUND

[0002] Since the birth of unmanned aerial vehicle technology, it has evolved from single speed domain task to multi-scene composite task. Early unmanned aerial vehicles mainly adopt fixed wing layout, aiming at low speed subsonic flight, and are applied to simple tasks such as reconnaissance and surveying. The wing configuration is fixed, and the design core is around subsonic stability and controllability. With the development of aerospace technology, the task demand of unmanned aerial vehicle is becoming more and more diversified. It not only needs to realize long endurance and accurate hovering at low speed, but also needs to have the ability of transonic speed maneuvering and high speed long range penetration. Wide speed domain flight has become the core technical demand of the new generation of unmanned aerial vehicles. The X61A is a representative air-launched unmanned aerial vehicle. The core configuration is a subsonic fixed flat wing layout, that is, the wing adopts a folding design, is folded and stored in the cargo compartment of the mother plane before launch, and is unfolded into a fixed angle flat wing after air release. It is mainly used for subsonic low speed patrol, target reconnaissance and other tasks. Its design core is around air launch compatibility and subsonic stability. Existing oblique wing technology is mainly applied to large manned aircraft or specific high speed aircraft, and there are two typical schemes: one is fixed oblique angle oblique wing, which is fixed at a certain angle with the center axis of the fuselage, and cannot be dynamically adjusted; the other is a simple adjustable oblique wing, which can be rotated but has low adjustment precision, and does not combine the lightweight and high reliability requirements of air-launched unmanned aerial vehicles, and does not form a collaborative design of multiple modes and wide speed domain. Obviously, the main defects of the existing design are narrow speed domain coverage, poor task adaptability, insufficient structure and aerodynamic collaborative design, weak environmental adaptability and other problems, which cannot meet the application requirements of wide speed domain, multi-task and high reliability unmanned aerial vehicles, and have low cross-modal task adaptability.

[0003] Therefore, there is an urgent need in the art for a wide speed domain flight unmanned aerial vehicle type design method to solve the above problems. SUMMARY

[0004] The present application provides a wide speed domain flight unmanned aerial vehicle type design method, which aims to dynamically solve the optimal wing oblique angle based on the aerodynamic-structure-environment coupling optimization model by real-time sensing of flight state parameters, realize adaptive adjustment of wing attitude, solve the problems of narrow speed domain coverage, poor task adaptability, stability and structural safety of existing unmanned aerial vehicles, and improve the full speed domain flight performance and multi-scene adaptability of unmanned aerial vehicles.

[0005] To achieve the above purpose, the present application provides a wide speed domain flight unmanned aerial vehicle type design method, comprising: Step 1: Obtain real-time flight state parameters of the unmanned aerial vehicle; Step two, based on the preset aerodynamic-structure-environment coupling optimization model, solve the optimal wing skew angle adapting to the current flight condition; Step three, according to the optimal wing skew angle control wing drive device, realize the switching of wing skew angle; Step four, dynamically perceive the flight state change in the flight process, and real-time update the optimal wing skew angle and adjust the wing attitude.

[0006] According to the specific embodiments provided by the application, the following technical effects are disclosed: The application can make the unmanned aerial vehicle run at the best balance point of aerodynamic performance and flight stability within the whole flight envelope of 0-1.8Ma through the aerodynamic-structure-environment coupling optimization model, thereby significantly enhancing the task adaptability, expanding the flight envelope, realizing wide-speed-domain flight through skew angle adjustment, having strong task adaptability, and being capable of flexibly performing low-speed long-time monitoring, high-speed penetration reconnaissance and other various differentiated tasks on the same flight platform, and having higher cost performance. BRIEF DESCRIPTION OF DRAWINGS

[0007] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the different views of the drawings, and wherein the same reference numbers in different drawings represent the same or similar components.

[0008] Figure 1 The wide-speed-domain flight unmanned aerial vehicle type design method flowchart shown in the embodiments of the application. DETAILED DESCRIPTION

[0009] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0010] Embodiment 1: see Figure 1 , Figure 1 The flowchart of the wide-speed-domain flight unmanned aerial vehicle type design method, a wide-speed-domain flight unmanned aerial vehicle type design method, characterized by comprising the following steps: Step one, obtaining real-time flight state parameters of the unmanned aerial vehicle; Step two, based on the preset aerodynamic-structure-environment coupling optimization model, solving the optimal wing skew angle adapting to the current flight condition; Step three, according to the optimal wing skew angle control wing drive device, realize the switching of wing skew angle; Step four, dynamically perceive the flight state changes during flight, update the optimal wing skew angle in real time and adjust the wing posture.

[0011] Specifically, the embodiment realizes the wing posture adaptive optimization of the unmanned aerial vehicle under different flight conditions through the flow of parameter acquisition, optimal skew angle calculation, skew angle switching and dynamic adjustment, establishes the correlation between the flight state and the wing skew angle based on the aerodynamic-structure-environment coupling optimization model, ensures the aerodynamic efficiency, structural safety and flight stability of the unmanned aerial vehicle in a wide speed range, covers multiple task scenarios from low-speed inspection to high-speed penetration, and solves the problems of narrow speed range coverage and poor task adaptability of traditional fixed-wing or simple adjustable skew wing unmanned aerial vehicles.

[0012] In a specific embodiment, the real-time flight state parameters in step one include Mach number, dynamic pressure, turbulence intensity and aerodynamic stability index.

[0013] Specifically, the Mach number reflects the ratio of the flight speed of the unmanned aerial vehicle to the local speed, and is the basis for dividing the low-speed, transonic and high-speed flight intervals; the dynamic pressure is used to reflect the pressure of the airflow on the surface of the aircraft, and to evaluate the structural load level; the turbulence intensity is used to measure the pulsation degree of the airflow in the flight environment, and reflects the influence of environmental disturbance on flight stability; and the aerodynamic stability index is the static stability margin characterizes the longitudinal stability of the unmanned aerial vehicle, and the above parameters are collected in real time by the onboard sensors (speed sensor, pressure sensor, weather sensor, aerodynamic parameter calculation module, etc.) of the unmanned aerial vehicle.

[0014] In a specific embodiment, the optimization target of the aerodynamic-structure-environment coupling optimization model in step two is to solve the skew angle that minimizes the generation value, i.e. the optimal wing skew angle , specifically: wherein, is the wing skew angle, which is a controllable quantity; is the current Mach number, is the current dynamic pressure, is the turbulence intensity, is the structural limit dynamic pressure, is the aerodynamic weight, is the stability weight, is the structure weight, is the wave resistance growth index, is the critical Mach number, is the current static stability margin, is the ideal static stability margin, is the environmental sensitivity coefficient.

[0015] Specifically, the coupling optimization model converts the performance requirements in the three dimensions of aerodynamics, structure, and environment into a single comprehensive generation value through weighted summation, and determines the optimal dihedral angle with the goal of minimizing the generation value ; wherein, is a mathematical optimization symbol, representing "find the dihedral angle that minimizes the comprehensive generation value in the parentheses "; the first term in the model is the aerodynamic wave drag cost term, used to control the shock wave drag in the transonic and high-speed stages, wherein, can reduce the effective Mach number and suppress the wave drag growth; the second term is the stability deviation cost term, used to ensure that the longitudinal stability of the unmanned aerial vehicle meets the ideal requirements, wherein, and are introduced to achieve stability compensation under environmental disturbances; the third term is the structural load cost term, used to avoid structural overload caused by excessive dynamic pressure, wherein, reflects the influence of the dihedral angle on the wing root load; the three terms work together to achieve a coupling balance of aerodynamic performance, structural safety, and environmental adaptability, ensuring that the optimal dihedral angle calculated is suitable for the current flight conditions.

[0016] In one specific embodiment, the parameter values set in the aerodynamic-structural-environmental coupling optimization model are: =1, =20, =2.5, =4, =0.75, =0.1, =5.

[0017] Specifically, the aerodynamic weight =1 is used to indicate that aerodynamic performance is the basic requirement; the stability weight =20 is used to highlight the core role of flight stability for safety, ensuring that stability deviation is prioritized for control; the structural weight =2.5 is used to reflect the bottom-line status of structural safety, which has a higher priority than aerodynamic performance; the wave drag growth index =4 conforms to the aerodynamic characteristics of the exponential growth of wave drag with Mach number in the transonic stage; the critical Mach number =0.75 corresponds to the speed threshold at which local supersonic airflow begins to appear on the wing surface; the ideal static stability margin =0.1 is determined based on the multi-task requirements of low speed, high speed, etc.; and the environmental sensitivity coefficient =5The influence of enlarged turbulence on stability is determined by strong turbulence environment flight test, the influence on stability is ensured when the environment is disturbed, the fixed value makes the model have clear engineering realizability, and the value can be adjusted based on actual work.

[0018] In a specific embodiment, when the optimal wing dihedral angle is solved in step two, three flight intervals are divided according to the flight speed, including: When the flight speed is lower than the first threshold 0.3Ma, it is determined as a low-speed or subcritical flight interval; When the flight speed is higher than the first threshold and lower than the second threshold 1.2Ma, it is determined as a transonic or medium-high speed flight interval; When the flight speed is higher than the second threshold 1.2Ma, it is determined as a high-speed flight interval.

[0019] Specifically, the first threshold 0.3Ma is the dividing point between low speed and transonic speed, which is far below the critical Mach number =0.75, no obvious shock wave is generated on the wing, and the aerodynamic wave resistance can be ignored; the second threshold 1.2Ma is the dividing point between transonic speed and high speed, at which the body has completely entered the supersonic flow field, the dynamic pressure is significantly increased, and the structural load becomes a key constraint; by dividing the three intervals through the two thresholds, the optimal dihedral angle calculation is more targeted, avoiding the performance imbalance of a single algorithm in different speed domains, and ensuring that the dihedral angle adjustment in each interval can match the core requirements of the current speed domain, such as low-speed stage focusing on stability and lift-drag ratio, transonic stage focusing on drag reduction, and high-speed stage focusing on the balance between structural safety and aerodynamic efficiency.

[0020] In a specific embodiment, after dividing the three flight intervals according to the flight speed, if the current belongs to the low-speed or subcritical flight interval, the wing dihedral angle is controlled to be 0°, maintaining the ideal static stability margin and obtaining the maximum lift-drag ratio; If the current belongs to the transonic or medium-high speed flight interval, the wing dihedral angle is controlled to be 60°-75°, to suppress the shock wave intensity and reduce the wave resistance; If the current belongs to the high-speed flight interval, the wing dihedral angle is controlled to be 45°±5°, to balance the structural safety and aerodynamic efficiency and reduce the root load.

[0021] Specifically, if the flight speed of the unmanned aerial vehicle is lower than the first threshold 0.3Ma, it means that it is in the low-speed region; at this time, since it is far less than the critical value , the first term in the formula is close to 0; at the same time, the dynamic pressure is low, and the third term can also be ignored; it is mainly affected by the second term Constraints, keeping the wing at a 0° deployment angle, not only make Maintaining the ideal value Nearby, it can provide the maximum wing aspect ratio at low speeds and obtain a higher lift-to-drag ratio, thereby improving the stability of the UAV after launch or during low-speed inspection. When the flight speed is higher than the first threshold but lower than the second threshold of Mach 1.2, it indicates that the drone is in the transonic region; as the speed approaches or exceeds... The first term of the formula It grows exponentially, becoming the dominant cost factor; to minimize the cost, it is necessary to increase... To reduce the effective Mach number Therefore, adjusting the wing to an angle of approximately 60°–75° effectively suppresses shock wave intensity and reduces wave drag; simultaneously, the second term of the formula introduces the turbulence factor. If there are gusts of wind in the environment As the angle is increased, the model will automatically fine-tune the angle to reduce drag while preventing excessive shift of the aerodynamic center and improving longitudinal static stability characteristics. If the drone's flight speed exceeds the second threshold, it enters the high-speed flight region; at this point, although a large sweep angle is still required aerodynamically, the dynamic pressure increases sharply and approaches its limit. The weight of the third term in the formula A significant increase; if the angle continues to be large, The resulting asymmetric moment will cause the cost function to surge. In this case, in order to protect the airframe structure, the model will adjust the wing back to an angle of about 45°. This angle is the balance point between structural safety and aerodynamic efficiency. It can significantly reduce the effective leading edge frontal area under high-speed flow field and reduce the root load by reducing the lever arm, enabling the UAV to complete high-speed maneuvering or long-distance cruise missions with a higher structural safety margin.

[0022] In one specific implementation, during the dynamic adjustment of wing attitude in step four, if the flight speed is at a threshold critical point or encounters sudden strong turbulence, the stability weight will be adjusted. Doubling the angle shifts the optimal tilt angle towards a smaller angle with better stability.

[0023] Specifically, when judging flight speed and thresholds, if the drone's current flight speed happens to be at the critical point, or if it encounters sudden strong turbulence, it will not rigidly choose a fixed angle, but will dynamically evaluate it through an objective function, that is, when... When it increases, the weight of the stability term Double, make Shift towards a smaller angle for better stability, thereby ensuring the angle of inclination. The selection criteria include accuracy, safety, and environmental adaptability.

[0024] In one specific embodiment, the unmanned aerial vehicle is designed based on the above-mentioned control logic; the unmanned aerial vehicle adopts a tail seat layout, the wings are installed at the middle and rear part of the body through wing root hinges, and the wing driving device includes a skew angle driving mechanism and a skew angle positioning mechanism for driving the wings to realize skew angle switching and positioning around the longitudinal axis of the body Specifically, the unmanned aerial vehicle is designed based on the above-mentioned adjustment logic, wherein the tail seat layout enables the unmanned aerial vehicle to have vertical take-off and landing and horizontal flight capabilities, adapt to the initial attitude adjustment requirement after air release, and simplify the body structure and reduce the space occupation during air storage; the wings are installed at the middle and rear part of the body through wing root hinges, the hinge structure provides mechanical support for the rotation of the wings around the longitudinal axis of the body (i.e. the central axis in the front-rear direction of the fuselage), and ensures the structural reliability during skew angle adjustment; in the wing driving device, the skew angle driving mechanism can adopt a servo motor, a hydraulic push rod or a pneumatic actuator, etc., to provide the power required for the rotation of the wings, drive the wings to rotate to the target angle according to the optimal skew angle instruction output by the flight control system, and the skew angle positioning mechanism can adopt an angle sensor, a limit switch or a locking pin, etc., to detect the current angle of the wings in real time, lock the position after the wings reach the target angle, and prevent the angle from deviating during flight, which provides hardware support for the accurate and stable switching of the skew angle of the wings.

[0025] The above has described the embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical application or improvement of technology in the market of the embodiments, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of designing an unmanned aerial vehicle configuration for wide speed regime flight, characterized by, The method comprises the following steps: Step one, obtaining real-time flight state parameters of the UAV; Step two, based on the preset aerodynamic-structure-environment coupling optimization model, solving the optimal wing skew angle adapting to the current flight condition; Step three, controlling the wing driving device according to the optimal wing skew angle to realize the switching of the wing skew angle; Step four, dynamically sensing the change of the flight state during the flight, and updating the optimal wing skew angle and adjusting the wing attitude in real time.

2. The wide speed range flight of unmanned aerial vehicle design method according to claim 1, characterized in that, The real-time flight state parameters in step one include Mach number, dynamic pressure, turbulence intensity and aerodynamic stability index.

3. The wide speed range flight capable unmanned air vehicle design approach of claim 1, wherein, The optimization objective of the aerodynamic-structural-environmental coupling optimization model in step two is to solve the oblique angle that minimizes the value of the generation, and the optimal wing oblique angle , conforms to the following formula: wherein, is the wing skew angle, is a controllable quantity; is the current Mach number, is the current dynamic pressure, is the turbulence intensity, is the structural limit dynamic pressure, is the aerodynamic weight, is the stability weight, is the structural weight, is the wave drag growth exponent, is the critical Mach number, is the current static stability margin, is the ideal static stability margin, is the environmental sensitivity coefficient.

4. The wide speed range flight capable unmanned air vehicle design method according to claim 3, wherein, The parameter values set in the air-structure-environment coupling optimization model are as follows: = 1, = 20, = 2.5, = 4, = 0.75, = 0.1, = 5.

5. The wide speed range flight of unmanned aerial system design method according to claim 3, wherein, In step two, when solving the optimal wing skew angle, three flight intervals are divided according to the flight speed, including: When the flight speed is lower than the first threshold 0.3Ma, it is determined as the low-speed or subcritical flight interval; When the flight speed is higher than the first threshold and lower than the second threshold 1.2Ma, it is determined as the transonic or medium-high speed flight interval; When the flight speed is higher than the second threshold 1.2Ma, it is determined as the high-speed flight interval.

6. The wide speed range flight of unmanned aerial system design method according to claim 5, wherein, After dividing the flight into three flight zones based on flight speed, if the current flight is in the low-speed or subcritical flight zone, the wing tilt angle is controlled. The angle is 0° to maintain ideal static stability margin and obtain maximum lift-to-drag ratio.

7. The wide speed range flight of unmanned aerial system design method according to claim 5, wherein, After dividing the flight into three flight zones based on flight speed, if the current flight zone is the transonic or medium-high speed zone, the wing tilt angle is controlled. The angle is 60° to 75° to suppress shock wave intensity and reduce wave impedance.

8. The wide speed range flight of unmanned aerial system design method according to claim 5, wherein, After dividing the flight into three flight zones based on flight speed, if the current flight zone is the high-speed zone, the wing tilt angle is controlled. The angle is 45°±5° to balance structural safety and aerodynamic efficiency, and to reduce root load.

9. The wide speed range flight capable unmanned air vehicle design method according to claim 3, wherein, When dynamically adjusting the wing attitude in step four, if the flight speed is at the threshold critical point or encounters a sudden strong turbulence, the stability weight is doubled, making the optimal dihedral angle shift to a small angle that is more optimal for stability.

10. The wide speed range flight of unmanned aerial vehicle design method according to claim 1, characterized in that, Further comprising: The UAV adopts a tail seat type layout, and the wing is installed on the middle and rear part of the body through a wing root hinge, the wing driving device comprises a skew angle driving mechanism and a skew angle positioning mechanism, which are used to drive the wing to realize skew angle switching and positioning around the longitudinal axis of the body.

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