A method and system for cooperative control of multi-modal flight of an aircraft, and an aircraft

Abstract

The application relates to the technical field of aircraft design, and discloses a cooperative control method and system for multi-mode flight of an aircraft and the aircraft. The method comprises the following steps: S1. a cruising efficiency optimization step: in a cruising flight mode, current Mach number, an angle of attack and real-time pressure distribution data from a pressure sensor array arranged at the rear of the upper surface of a main wing of the aircraft are acquired; based on the Mach number and the angle of attack, a target pressure distribution feature under the current working condition is solved in real time through a pre-stored optimization model; the working parameters of a boundary layer management propulsion module integrated in the main wing are dynamically adjusted so that the real-time pressure distribution data approaches the target pressure distribution feature; and S2. a mode conversion cooperation step: in response to a command for conversion to a vertical take-off and landing mode, a preset cooperative conversion sequence is executed. The system-level unification of cruising aerodynamic efficiency and vertical take-off and landing flexibility significantly improves the mode conversion stability and the comprehensive efficiency of the whole task profile.

Description

Technical Field

[0001] This invention relates to the field of aircraft design technology, and in particular to a cooperative control method, system and aircraft for multimodal flight of an aircraft. Background Technology

[0002] Cruise efficiency and takeoff and landing flexibility are two core indicators for measuring the overall performance of an aircraft; however, there is a profound contradiction between the two in traditional technological approaches. Fixed-wing aircraft rely on their wings to generate aerodynamic lift during forward flight, boasting advantages such as high lift-to-drag ratio, long range, and good economy. However, their takeoff and landing heavily depend on long runways, placing high demands on infrastructure. While vertical / short takeoff and landing (V / STOL) aircraft are free from runway constraints, their rotor or lift fan-based configurations often result in low efficiency, short range, and slow speed during cruise. Their lift systems become ineffective loads during the cruise phase, limiting their application scope.

[0003] To reconcile this contradiction, the industry has proposed various solutions, including distributed electric propulsion, tiltrotor / rotor systems, and compound configurations. For example, the F-35B fighter jet uses a complex mechanical transmission scheme of "lift fan + downward deflection of main engine nozzles" to achieve vertical takeoff and landing, but this system is bulky, complex to maintain, and its lift fan becomes a dead weight during cruise. Some electric vertical takeoff and landing aircraft use a compound configuration of multi-rotor and fixed-wing aircraft, switching between hovering and cruise modes, but the aerodynamic and propulsion systems of the two are relatively independent, failing to achieve deep coupling optimization of energy and aerodynamics.

[0004] Boundary layer suction technology, as a cutting-edge approach to improving aircraft aerodynamic efficiency, has been extensively studied. This technology aims to draw low-speed boundary layer airflow from the wing or fuselage surface into the engine, accelerate it, and then expel it, thereby reducing drag and improving propulsion efficiency. However, existing research mostly treats boundary layer suction as a single aerodynamic drag reduction method, and mature solutions for deeply integrating it into multi-modal flight management systems (especially those including vertical takeoff and landing modes) are yet to be seen. Seamlessly, safely, and efficiently integrating the efficient boundary layer suction cruise mode with the high-power-demand vertical takeoff and landing mode faces a series of systemic challenges, including aerodynamic layout, thrust management, and mode transition control.

[0005] Therefore, there is an urgent need in this field for an innovative systemic solution, based on a new architecture that integrates aerodynamic design, propulsion layout and intelligent control, based on top-level mission requirements, so as to truly achieve the organic unity of the two advantages of "efficient cruise" and "flexible take-off and landing". Summary of the Invention

[0006] The present invention aims to solve the technical problem that aircraft in the prior art cannot simultaneously achieve high-efficiency cruise flight and vertical / short take-off and landing capabilities, and overcome the defects of traditional solutions such as system redundancy, uneven mode switching, and low overall energy efficiency.

[0007] To achieve the above objectives, this invention proposes a cooperative control method for multimodal flight of an aircraft, executed by a multimodal cooperative flight controller, comprising the following steps: S1. Cruise efficiency optimization steps: In cruise flight mode, acquire the aircraft's current Mach number, angle of attack, and real-time pressure distribution data from a pressure sensor array located on the rear of the upper surface of the main wing; based on the Mach number and angle of attack, calculate the target pressure distribution characteristics under the current operating conditions in real time using a pre-stored optimization model; dynamically adjust the operating parameters of the boundary layer management propulsion module integrated into the main wing to make the real-time pressure distribution data approach the target pressure distribution characteristics; S2. Mode Conversion Coordination Steps: In response to a command to transition to a vertical takeoff and landing mode, a preset coordination conversion sequence is executed, which includes: S21. Thrust reference establishment stage: The fuselage lift module is activated and its thrust is controlled to increase to a reference value along a preset smooth curve. At the same time, the vector nozzle of the boundary layer management propulsion module is controlled to start deflecting downward at a time-variable rate, wherein the initial deflection rate is lower than the deflection rate in subsequent stages. S22. Dynamic decoupling control stage: During the continuous deflection of the vector nozzle, the attitude information of the aircraft is acquired in real time; based on the attitude information, the current ground speed and the altitude above the ground, a multivariable decoupling control algorithm is used to generate differentiated independent thrust adjustment commands for the boundary layer management propulsion module and the fuselage lift module to suppress the attitude deviation of the aircraft; S23. Lift responsibility handover phase: When the deflection angle of the vector nozzle reaches a preset intermediate angle, it is determined that the transition flight state has been entered. Based on an internal model describing the coupling relationship between the oblique thrust and the aerodynamic lift of the wing, a smooth handover process is initiated and executed from lift mainly provided by the fuselage lift module to lift mainly provided by the vertical thrust component of the boundary layer managed propulsion module.

[0008] Furthermore, the optimization model is a database or response surface model generated by joint calibration of computational fluid dynamics simulation and wind tunnel test data. Its input variables include at least Mach number and angle of attack, and the output variables are the desired pressure distribution characteristics of the rear of the wing surface.

[0009] Furthermore, the second derivative of the deflection angle of the vector nozzle with time is not zero, causing the deflection process to exhibit nonlinear acceleration characteristics.

[0010] Furthermore, the multivariable decoupled control algorithm is configured to: calculate or select a control allocation strategy online based on the real-time mass characteristics, aerodynamic derivatives, and current ground speed and altitude of the aircraft. This strategy decouples and maps the stable control commands for pitch and roll angles into independent and combinable thrust corrections for the left and right boundary layer management propulsion modules and the fuselage lift module.

[0011] Furthermore, the smooth handover process includes: based on the wing aerodynamic lift increment predicted by the internal model, reducing the thrust command to the fuselage lift module in a feedforward manner and proportionally, while simultaneously increasing the total thrust command to the boundary layer management propulsion module.

[0012] A multimodal cooperative flight system for aircraft, used to implement the above-described method, comprising: The boundary layer management propulsion module is integrated into the rear of the main wing, and is configured to form an aerodynamic blend with the main wing. It includes an air intake, a power unit, and a vectoring nozzle. The fuselage lift module is located on the fuselage of the aircraft. A multimodal cooperative flight controller is connected to the boundary layer management propulsion module, the fuselage lift module, and a sensor network signal. The sensor network is at least used to provide the multimodal cooperative flight controller with the flight state and attitude information necessary to achieve the above steps S1 and S22; The multimodal cooperative flight controller is configured to store and run the control logic described in the above-mentioned cooperative control method for multimodal flight of an aircraft.

[0013] Furthermore, in the aerodynamically integrated body formed by the boundary layer management propulsion module and the main wing, the air intake device has a lip, the profile of which is configured to smoothly transition with the upper surface of the trailing edge of the main wing at the cruise design point, so as to guide the boundary layer airflow on the upper surface of the wing into the power unit without separation.

[0014] Furthermore, the air intake lip of the wing-integrated adaptive air intake device has a specific geometric configuration, which forms a "V"-shaped cross-section channel at the trailing edge of the main wing that simultaneously covers the upper and lower surfaces of the wing, for synchronously drawing in boundary layer airflow from the upper and lower surfaces.

[0015] Furthermore, the deflectable vector nozzle is a multi-segment bendable nozzle, which is configured to continuously deflect within a range of 0 degrees to at least 90 degrees about an axis parallel to the transverse axis of the aircraft.

[0016] Furthermore, the fuselage lift module is a coaxial counter-rotating fan system, including an upper fan and a lower fan that are positioned vertically opposite each other and rotate in opposite directions.

[0017] Furthermore, the end of the deflectable vector nozzle and the outlet cover of the fuselage lift module are respectively provided with retractable support devices, which are arranged to form a stable three-point or multi-point support surface when the aircraft lands.

[0018] An aircraft is equipped with the aforementioned multimodal cooperative flight system, and its overall layout satisfies the following: the thrust center of the fuselage lift module is near the vertical projection of the aircraft's center of gravity, and the longitudinal distance between the thrust line position of the boundary layer management propulsion module and the aircraft's center of gravity is configured to facilitate stable attitude control in the cooperative transition sequence.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following significant advantages: System-level performance leap: Through active aerodynamic optimization during cruise, the lift-to-drag ratio and range are significantly improved; through intelligent thrust coordination during vertical takeoff and landing, efficient hovering and smooth transitions are achieved. From a full mission profile perspective, the overall effectiveness far exceeds that of a simple combination of "fixed-wing + vertical lift system".

[0020] Enhanced safety and reliability: The mode conversion sequence and control algorithm can actively predict and compensate for aerodynamic and torque disturbances during the conversion process, significantly reducing pilot workload and improving safety during complex flight phases.

[0021] Excellent technical scalability: The control method framework described can be adapted to aircraft of different sizes and power forms (pure electric, hybrid, hydrogen fuel), providing key technical support for the development of future urban air traffic and new general aviation aircraft. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating the main workflow of the collaborative control method of the present invention.

[0024] Figure 2 This is a schematic diagram of the multimodal cooperative flight system for aircraft of the present invention.

[0025] Figure 3 This is a schematic diagram of the aerodynamic integration configuration of the boundary layer management propulsion module and the main wing of the present invention.

[0026] Figure 4This is a schematic diagram of the structure of the rear part of the left main wing and the left air propulsion device of the present invention.

[0027] Figure 5 This is a schematic diagram illustrating the timing coordination between the thrust unit commands and the aircraft attitude changes during the mode conversion process of this invention.

[0028] Figure 6 This is a schematic diagram of the fuselage lift module (coaxial counter-rotating fan) of the present invention in the open state.

[0029] Figure 7 This is a schematic diagram illustrating the working principle of the multivariable decoupling control algorithm of the present invention.

[0030] Icon labels: 100-Left main wing; 130-Deflectable vector nozzle; 150-Left air propulsion device; 160-Left bleed air assembly; 161-Left air inlet; 161A-Top surface; 170-Left gas thruster; 180-Left jet assembly; 200-Right main wing; 289-Right landing gear; 400-Main wing; 410-Upper wing surface; 900-Fuselage; 91-Upper boundary laminar flow; 92-Lower boundary laminar flow; 950-Third air thruster; 960-Bleed air top cover; 970-Third gas thruster; 980-Exhaust bottom cover; 989-Mid-landing gear. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail and completely below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these descriptions are intended to illustrate the invention and not to limit its scope of protection. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0032] Example 1: This embodiment combines Figure 1 , Figure 2 and Figure 7 This paper provides a cooperative control method for multimodal flight of an aircraft, executed by a multimodal cooperative flight controller, comprising the following steps: The multimodal cooperative flight controller is the core of the method's execution, and it is connected to the sensor network (including the atmospheric data computer, inertial measurement unit, pressure sensor array, etc.) and the actuator network (including the left / right boundary layer management propulsion module and the fuselage lift module's driver).

[0033] S1. Cruise Efficiency Optimization Phase: Under cruise flight mode, acquire the aircraft's current Mach number, angle of attack, and real-time pressure distribution data from a pressure sensor array located at the rear of the upper surface of the main wing; based on the Mach number and angle of attack, calculate the target pressure distribution characteristics under the current operating conditions in real time using a pre-stored optimization model; dynamically adjust the operating parameters of the boundary layer management propulsion module integrated into the main wing to make the real-time pressure distribution data approach the target pressure distribution characteristics; (corresponding to...) Figure 1 (S1 step)

[0034] The controller continuously receives data from the sensor network. When the aircraft is in a stable cruise state (e.g., at a cruise design point, such as Mach 0.65 and angle of attack 3°), the controller initiates a cruise efficiency optimization cycle.

[0035] Data Acquisition and Feature Extraction: The controller reads the current Mach number (Ma), angle of attack (α), and pressure data from pressure sensor arrays located near the trailing edges of the upper surfaces of the left and right wings (e.g., at a position 5%-15% of the chord length from the trailing edge). The controller processes this raw pressure data to extract "feature values" that characterize the current pressure distribution on the wing surface. These feature values ​​can be scalars or vectors processed by an algorithm; for example, they can be the norm of the deviation between the weighted average pressure at several key measuring points on the trailing edge and the theoretical ideal value.

[0036] Target Query and Error Generation: The controller has a pre-stored "aerodynamic optimization database." This database was generated through extensive computational fluid dynamics (CFD) simulations and wind tunnel tests, establishing the wing target pressure distribution characteristics corresponding to optimal cruise efficiency under different Mach number and angle of attack combinations. The controller uses the current value (Ma, α) as an index to retrieve the corresponding "target characteristic value" from the database.

[0037] Closed-loop control: The controller compares real-time characteristic values ​​with target characteristic values ​​to generate an error signal. Based on this error, a proportional-integral-derivative (PID) or other advanced control algorithm is used to calculate adjustment commands for the left boundary layer managed propulsion module L and the right boundary layer managed propulsion module R. These commands may include: fine-tuning the speed of the electric ducted fan in the propulsion module (to change the suction intensity), or fine-tuning the pitch angle of the vector nozzle (to change the combing effect of the jet on the tail flow field of the wing). This closed-loop control continues, ensuring that the wing always operates near the combination of angle of attack and Mach number corresponding to the highest aerodynamic efficiency. This process is dynamic and adaptive, unlike any fixed operating mode, such as... Figure 1 As shown, the loop continues until a mode switching command is received; S2. Mode transition coordination phase (corresponding to) Figure 1In step S2, receiving the vertical takeoff and landing conversion command: In response to the command to switch to vertical takeoff and landing mode, a preset cooperative conversion sequence is executed, which includes: When the pilot issues the "switch to hover" command, the controller automatically executes the preset "cooperative transition sequence".

[0038] S21. Thrust reference establishment stage: The fuselage lift module is activated and its thrust is controlled to increase to a reference value along a preset smooth curve. At the same time, the vector nozzle of the boundary layer management propulsion module is controlled to start deflecting downward at a time-variable rate, wherein the initial deflection rate is lower than the deflection rate in subsequent stages. The controller immediately sends a start command to the airframe lift module. The module's cover opens, and the coaxial counter-rotating fan begins to spin. The controller controls its thrust to gradually increase along an S-curve to a baseline thrust value F_base (e.g., 35% of the aircraft's current weight) within a preset time period T_pre (e.g., 2 seconds). Simultaneously, the controller instructs the vectoring nozzles of the left and right propulsion modules to begin deflecting downwards. The key innovation here is that the deflection angular velocity is not constant. Δt1 represents the initial time window for the vectoring nozzles to deflect at a lower angular velocity. In the initial Δt1 (e.g., 0.5 seconds), the angular velocity is low (e.g., 10° / s), allowing sufficient time for the lift module's thrust to initially build up and counteract any small pitching moment disturbances that may occur when the nozzles begin to deflect downwards. Subsequently, the angular velocity rapidly increases to a higher value (e.g., 30° / s) to accelerate the transition process. This "slow at first, fast later" nonlinear time-varying rate design is a crucial guarantee for smooth transition.

[0039] S22. Dynamic decoupling control stage: During the continuous deflection of the vector nozzle, the attitude information of the aircraft is acquired in real time; based on the attitude information, the current ground speed and the altitude above the ground, a multivariable decoupling control algorithm is used to generate differentiated independent thrust adjustment commands for the boundary layer management propulsion module and the fuselage lift module to suppress the attitude deviation of the aircraft; As the vectoring nozzle continues to deflect downwards, the aerodynamic center of the aircraft shifts rapidly, and any slight imbalance in the left-right thrust is amplified. At this point, such as... Figure 7 As shown, the multivariable decoupling control algorithm begins to play a core role.

[0040] Input: The algorithm receives pitch angle θ, roll angle Φ deviation, current ground speed V_ground and ground clearance H from the inertial measurement unit (IMU) in real time.

[0041] Processing: The controller internally maintains a control allocation matrix or its equivalent algorithmic logic. This matrix / logic is not fixed; its parameters are updated or selected online based on the current mass characteristics of the aircraft, estimated aerodynamic derivatives, and critical values ​​V_ground and H. For example, the control strategy differs in the "ground effect" zone very close to the ground compared to higher altitudes.

[0042] Output: The algorithm resolves attitude stabilization commands (such as "need to add a nose-down moment") into a set of differentiated thrust fine-tuning commands for the three thrust units (left thrust module, right thrust module, and fuselage lift module). For example, generating a pure nose-down moment might require a slight increase in thrust from the lift module, while the two thrust modules simultaneously reduce thrust slightly. This decoupling capability ensures precise attitude control under all conditions.

[0043] S23. Lift responsibility handover phase: When the deflection angle of the vector nozzle reaches a preset intermediate angle, it is determined that the transition flight state has been entered. Based on an internal model describing the coupling relationship between the oblique thrust and the aerodynamic lift of the wing, a smooth handover process is initiated and executed from the lift mainly provided by the fuselage lift module to the lift mainly provided by the vertical thrust component of the boundary layer managed propulsion module.

[0044] When the vector nozzle deflects to about 45° (the preset intermediate angle), the aircraft enters the "transition flight state"—at this time, the thrust of the propulsion module has both rearward and upward components, and the wings begin to generate some aerodynamic lift because they still have forward speed.

[0045] like Figure 7 As shown, the controller predicts the lift L_wing generated by the wing at this time based on a preset internal model (which describes the aerodynamic lift increment that the wing can generate at a given airspeed, angle of attack and nozzle angle).

[0046] Based on this prediction, the controller initiates a "lift responsibility handover" process: it begins to feedforward and reduce the thrust command F_lift to the fuselage lift module by a certain proportional coefficient. Simultaneously, to maintain a constant total lift, it synchronously increases the total thrust command F_prop to the left and right propulsion modules L / R according to the model relationship. This process continues until the vector nozzles reach 90° (vertically downward), and the aircraft fully enters a hovering state. At this point, the fuselage lift module may only need to provide 15-25% of the total lift, with most of the lift provided by the relatively more efficient propulsion modules L / R, which are operating vertically, thus optimizing hovering power consumption.

[0047] The core idea of ​​this method is to treat the entire mission profile of the aircraft as a whole, and implement two core strategies through a central intelligent controller (multimodal cooperative flight controller). During the cruise phase, active boundary layer optimization management based on real-time aerodynamic feedback is implemented, dynamically adjusting suction parameters to ensure the wing always operates in a near-optimal aerodynamic state. When transitioning to vertical takeoff and landing (VTOL) mode, a pre-set cooperative transition sequence is implemented, incorporating nonlinear timing and dynamic decoupling control. This sequence is not a simple superposition of actions, but a closed-loop process considering aerodynamic coupling, torque balance, and energy optimization, ensuring a highly stable and safe transition process.

[0048] Example 2: Detailed Example of System Hardware Configuration

[0049] This embodiment combines Figure 3 and Figure 4 Please describe in detail the hardware system that supports the implementation of the above methods.

[0050] The present invention discloses a multimodal cooperative flight system for aircraft, the optimal implementation platform of which can be a fixed-wing aircraft platform having the following characteristics: it includes a fuselage 900, a left main wing 100, and a right main wing 200. To achieve the efficient cruise and stable vertical take-off and landing (VTOL) objectives of the present invention, the platform specifically adopts the following integrated design: Deep integration configuration of the boundary layer management propulsion module: The left main wing 100 is integrally constructed with the left air propulsion system 150 at its rear. This system includes a left bleed air duct 160, a left gas thruster 170, and a left jet duct 180, all connected longitudinally along the flight direction. The configuration of the left air intake 161 of the left bleed air duct 160 is crucial: its top surface 161A smoothly transitions to the upper rear surface of the left main wing 100, and its bottom extends below the lower surface of the wing, thus forming a unique "V"-shaped air intake channel at the trailing edge of the wing (e.g., ...). Figure 4 (As shown). The core function of this configuration is to simultaneously and efficiently capture the upper boundary laminar flow 91 on the upper surface and the lower boundary laminar flow 92 on the lower surface of the left main wing 100, achieving full envelope boundary layer management. The right main wing 200 is symmetrically arranged.

[0051] Both the left jet nozzle 180 and the right jet nozzle are multi-segment rotatable nozzles, which can continuously deflect more than 90 degrees between the longitudinal direction (providing cruise thrust) and the normal direction (providing vertical lift) under the command of the controller of this invention. This is the core actuator for realizing thrust vector conversion.

[0052] Specific implementation of the fuselage lift module: like Figure 5As shown, a third air thrust device 950 is provided near the center of gravity of the fuselage 900 as the fuselage lift module of the present invention. It includes an openable bleed air top cover 960 and an exhaust air bottom cover 980, and a third gas thruster 970 disposed therein. This thruster preferably includes a set of upper and lower fans arranged symmetrically about the Z-axis and rotating in opposite directions to counteract torque. A grounding component 989 is integrated on the exhaust air bottom cover 980.

[0053] Integrated design of takeoff and landing support: The left and right jet pipes integrate the left and right landing sub-components 289 at their ends, which together with the mid-landing sub-component 989 of the fuselage lift module form a triangular landing support system. This support point layout not only serves as a load-bearing structure, but also acts as a reference point for ground contact sensing during takeoff and landing, enabling precise feedback and active leveling of the landing attitude.

[0054] like Figure 2 and Figure 3 As shown, the boundary layer management propulsion module employs a deeply integrated design. Its intake lip is not externally mounted but is integrated with the trailing edge structure of the main wing 400, forming an "aerodynamically integrated body." The lower surface of the lip smoothly transitions to the upper surface of the wing at the junction, and its profile has been specially optimized to ensure that, at the cruise design point (e.g., Mach 0.6), the boundary layer airflow from the upper surface 410 of the wing can be smoothly "guided" into the intake channel with minimal flow separation loss. The boundary layer management propulsion module internally includes a high-power-density electric ducted fan and a deflectable vectoring nozzle 130.

[0055] like Figure 6 As shown, the fuselage lift module employs a coaxial counter-rotating fan design. The upper and lower fans are driven by the same motor or by two separate motors, but rotate in opposite directions, thus naturally canceling out torque and eliminating the need for an additional tail rotor or yaw control torque compensation mechanism. The fuselage lift module housing includes a quick-opening and closing cover, which is closed during cruise to maintain a clean fuselage surface.

[0056] The system comprises three key subsystems: Boundary layer management propulsion module: Deeply integrated into the trailing edge of the main wing, its configuration forms an aerodynamic blend with the wing, and has the dual functions of generating thrust and actively managing the wing flow field.

[0057] Fuselage lift module: Independently located on the fuselage, it serves as one of the main lift sources during vertical takeoff and landing, and works in conjunction with the wing module during the transition process.

[0058] Multimodal cooperative flight controller: As the "brain" of the system, it connects with various sensors and actuators and is responsible for running the aforementioned cooperative control methods.

[0059] Example 3: Implementation and Extended Applications of the Controller

[0060] The multimodal cooperative flight controller can adopt a multi-core processor architecture, with one core dedicated to running high-frequency real-time control algorithms (such as decoupling algorithms), and another core handling status monitoring, task management, etc. Its internal software adopts a modular design, which facilitates upgrades and maintenance.

[0061] The control framework of this invention has good scalability. For example, for larger aircraft, more than two boundary layer management propulsion modules can be arranged on the main wing 400. In this case, the dimension of the control allocation matrix increases accordingly, but the core concepts of "cooperative conversion sequence" and "multivariable decoupling control" still apply. Similarly, this system can also be applied to unmanned aerial vehicles, with mode conversion commands sent by a ground station or onboard mission computer.

[0062] The overall layout of the aircraft is specially designed to accommodate and maximize the effectiveness of the systems and methods. For example, key geometric parameters such as the position of the lift module and the thrust line of the propulsion module are configured to facilitate smooth mode transition control.

[0063] It should be noted that the specific numerical values ​​(such as time, angle, percentage, etc.) mentioned in the above embodiments are merely illustrative examples used to clearly illustrate the principles and implementation methods of the present invention. Those skilled in the art can determine the appropriate parameters through conventional engineering design and simulation analysis based on the specific design goals of different aircraft (such as weight, thrust, cruise speed, etc.). These parameter adjustments and adaptive modifications based on the core ideas of the present invention all fall within the protection scope of the present invention.

[0064] The scope of protection of this invention is determined by the appended claims, and the description and drawings are used to interpret the claims. Those skilled in the art, after reading this description, can make various equivalent modifications and substitutions to this invention without inventive effort, and these should also be considered to fall within the scope of protection of this invention.

Claims

1. A cooperative control method for multimodal flight of an aircraft, characterized in that, Performed by the multimodal cooperative flight controller, the process includes the following steps: S1. Cruise efficiency optimization steps: In cruise flight mode, acquire the aircraft's current Mach number, angle of attack, and real-time pressure distribution data from a pressure sensor array located on the rear of the upper surface of the main wing; based on the Mach number and angle of attack, calculate the target pressure distribution characteristics under the current operating conditions in real time using a pre-stored optimization model; dynamically adjust the operating parameters of the boundary layer management propulsion module integrated into the main wing to make the real-time pressure distribution data approach the target pressure distribution characteristics; S2. Mode Conversion Coordination Steps: In response to a command to transition to a vertical takeoff and landing mode, a preset coordination conversion sequence is executed, which includes: S21. Thrust reference establishment stage: The fuselage lift module is activated and its thrust is controlled to increase to a reference value along a preset smooth curve. At the same time, the vector nozzle of the boundary layer management propulsion module is controlled to start deflecting downward at a time-variable rate, wherein the initial deflection rate is lower than the deflection rate in subsequent stages. S22. Dynamic decoupling control stage: During the continuous deflection of the vector nozzle, the attitude information of the aircraft is acquired in real time; based on the attitude information, the current ground speed and the altitude above the ground, a multivariable decoupling control algorithm is used to generate differentiated independent thrust adjustment commands for the boundary layer management propulsion module and the fuselage lift module to suppress the attitude deviation of the aircraft; S23. Lift responsibility handover phase: When the deflection angle of the vector nozzle reaches a preset intermediate angle, it is determined that the transition flight state has been entered. Based on an internal model describing the coupling relationship between the oblique thrust and the aerodynamic lift of the wing, a smooth handover process is initiated and executed from lift mainly provided by the fuselage lift module to lift mainly provided by the vertical thrust component of the boundary layer managed propulsion module.

2. The method according to claim 1, characterized in that, The optimization model is a database or response surface model generated by joint calibration of computational fluid dynamics simulation and wind tunnel test data. Its input variables include at least Mach number and angle of attack, and the output variables are the desired pressure distribution characteristics of the rear of the wing surface.

3. The method according to claim 1, characterized in that, The time-variable rate is specifically defined as follows: the second derivative of the deflection angle of the vector nozzle with time is not zero, causing the deflection process to exhibit nonlinear acceleration characteristics.

4. The method according to claim 1, characterized in that, The multivariable decoupled control algorithm is configured to: calculate or select a control allocation strategy online based on the real-time mass characteristics, aerodynamic derivatives, and current ground speed and altitude of the aircraft. This strategy decouples and maps the stable control commands for pitch and roll angles into independent and combinable thrust corrections for the left and right boundary layer management propulsion modules and the fuselage lift module.

5. The method according to claim 1, characterized in that, The smooth handover process includes: based on the wing aerodynamic lift increment predicted by the internal model, reducing the thrust command to the fuselage lift module in a feedforward manner and proportionally, while simultaneously increasing the total thrust command to the boundary layer management propulsion module.

6. A multimodal cooperative flight system for an aircraft, used to implement the method according to any one of claims 1 to 5, characterized in that, include: The boundary layer management propulsion module is integrated into the rear of the main wing, and is configured to form an aerodynamic blend with the main wing. It includes an air intake, a power unit, and a vectoring nozzle. The fuselage lift module is located on the fuselage of the aircraft. A multimodal cooperative flight controller is connected to the boundary layer management propulsion module, the fuselage lift module, and a sensor network signal. The sensor network is at least used to provide the multimodal cooperative flight controller with the flight state and attitude information necessary to achieve steps S1 and S22 in claim 1; The multimodal cooperative flight controller is configured to store and run the control logic as described in any one of claims 1 to 5.

7. The system according to claim 6, characterized in that, In the aerodynamically integrated body formed by the boundary layer management propulsion module and the main wing, the air intake device has a lip, the profile of which is configured to smoothly transition with the upper surface of the trailing edge of the main wing at the cruise design point, so as to guide the boundary layer airflow on the upper surface of the wing into the power unit without separation.

8. The system according to claim 6, characterized in that, The air intake lip of the wing-integrated adaptive air intake device has a specific geometric configuration, which forms a "V"-shaped cross-section channel at the trailing edge of the main wing that simultaneously covers the upper and lower surfaces of the wing, for synchronously drawing in boundary layer airflow from the upper and lower surfaces.

9. The system according to claim 6, characterized in that, The deflectable vector nozzle is a multi-segment bendable nozzle, which is configured to continuously deflect around an axis parallel to the transverse axis of the aircraft within a range of 0 degrees to at least 90 degrees.

10. The system according to claim 6, characterized in that, The fuselage lift module is a coaxial counter-rotating fan system, including an upper fan and a lower fan that are positioned vertically opposite each other and rotate in opposite directions.

11. The system according to claim 6, characterized in that, The deflectable vector nozzle and the outlet cover of the fuselage lift module are respectively equipped with retractable support devices, which are arranged to form a stable three-point or multi-point support surface when the aircraft lands.

12. An aircraft, characterized in that, The aircraft is equipped with a multimodal cooperative flight system as described in any one of claims 6 to 11, and its overall layout satisfies the following: the thrust center of the fuselage lift module is near the vertical projection of the aircraft's center of gravity, and the longitudinal distance between the thrust line position of the boundary layer management propulsion module and the aircraft's center of gravity is configured to facilitate stable attitude control in the cooperative transition sequence.

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