Motion modeling method for ground-effect aircraft in three-dimensional random sea wave environment

Abstract

The invention belongs to the field of aircraft motion modeling, and particularly relates to a ground-effect aircraft motion modeling method in a three-dimensional random sea wave environment. Comprising the following steps: establishing a storm environment model including a sea wave model and a wind field model; according to the sea wave model, establishing a ground-effect aircraft aerodynamic model in the wave environment based on a movable wave floor wind tunnel test result of the ground-effect aircraft; establishing a ground-effect aircraft aerodynamic model with boundary layer control based on the wind tunnel test with boundary layer control of the ground-effect aircraft; according to the aerodynamic model of the ground-effect aircraft in the wave environment and the aerodynamic model of the ground-effect aircraft with boundary layer control, establishing a total motion model of the ground-effect aircraft in the three-dimensional random sea wave environment, the full-amount motion model comprises a six-degree-of-freedom full-amount dynamics and kinematics equation, a pneumatic model, a water surface acting force model and a boundary layer control blowing model; and performing small disturbance linearization on the total model to obtain a ground-effect aircraft linearization motion model considering atmospheric disturbance and sea wave disturbance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of aircraft motion modeling, and particularly relates to a ground effect aircraft motion modeling method in a three-dimensional random sea wave environment. BACKGROUND

[0002] The ground effect aircraft is also called ground effect wing ship or wing boat, and is a low-altitude carrier tool flying near the ground or water surface, utilizing the ground effect to improve the wing surface lift and reduce the induced drag, so as to realize the optimization of flight performance. In the marine environment, the ground effect aircraft faces complex three-dimensional random sea wave disturbance, which not only causes the vertical and horizontal position changes of the aircraft, but also may cause the attitude changes of the aircraft, thereby affecting the stability of the flight control system and the flight performance. Therefore, how to accurately simulate and predict the motion behavior of the ground effect aircraft in the complex sea wave environment is a key problem to be solved in the design, performance evaluation and control strategy optimization of the ground effect aircraft. In the existing technology, the motion modeling method of the ground effect aircraft mainly depends on a simplified two-dimensional sea wave model or a steady aerodynamic analysis based on the static sea surface wave characteristics. These methods fail to fully consider the three-dimensional randomness of the sea wave in the actual marine environment and the complex coupling relationship between the wave and the aerodynamic effect. Therefore, under the condition of the variable and irregular sea wave, the flight dynamics of the aircraft cannot be accurately predicted by using the traditional modeling method, and especially in the nonlinear disturbance and extreme sea conditions, the prediction result of the flight performance may have a large deviation.

[0003] In order to more accurately describe the dynamic response of the ground effect aircraft in the complex sea wave environment, some researches begin to try to use more complex three-dimensional random sea wave models. These models can more realistically reproduce the randomness, time-varying nature and spatial correlation of wave propagation of the sea wave. However, most of the current research results are concentrated on the separate application of sea wave modeling or aerodynamic modeling, and lack of comprehensive methods for coupling analysis of sea wave and aerodynamic effect. This makes it difficult to meet the requirements of accuracy and computational efficiency at the same time in the actual application based on the motion model of the ground effect aircraft in the existing technology. In view of the above background, the existing technology fails to provide a comprehensive, accurate and efficient ground effect aircraft motion modeling method in a three-dimensional random sea wave environment, especially in the simulation of the coupling of sea wave and aerodynamic effect and nonlinear dynamic response. With the increasing application demand of the ground effect aircraft in the complex sea conditions, a new technical scheme is urgently needed to solve the problems of sea wave modeling, aerodynamic modeling and coupling effect, so as to provide more accurate and reliable technical support for the design, flight control and sea task execution of the ground effect aircraft. SUMMARY

[0004] The application aims to provide a ground effect aircraft motion modeling method in a three-dimensional random sea wave environment, so as to ensure the flight stability and safety of the ground effect aircraft in the complex sea conditions.

[0005] Technical solution: A ground effect aircraft motion modeling method in a three-dimensional random sea wave environment, comprising: Step 1: Establish a wind wave environment model, the wind wave environment model comprising a sea wave model and a wind field model; Step 2: According to the sea wave model, the ground effect aircraft aerodynamic model in the wave environment is established based on the active wave floor wind tunnel test results of the ground effect aircraft; Step 3: The ground effect aircraft aerodynamic model with boundary layer control is established based on the wind tunnel test with boundary layer control of the ground effect aircraft; Step 4: According to the ground effect aircraft aerodynamic model in the wave environment and the ground effect aircraft aerodynamic model with boundary layer control, a full motion model of the ground effect aircraft in a three-dimensional random sea wave environment is established, wherein the full motion model comprises: six degrees of freedom full dynamics and kinematics equations, an aerodynamic model, a water surface force model, and a boundary layer control blowing model; Step 5: Linearize the full model by small perturbation to obtain a linearized motion model of the ground effect aircraft considering atmospheric disturbance and sea wave disturbance.

[0006] Further, in step 1, the sea wave model is a random sea wave model established based on the Longuet-Higgins model of P-M sea wave spectrum, and the wind field model is a Von Karman atmospheric turbulence model.

[0007] Further, in step 2, the ground effect aircraft aerodynamic model in the wave environment comprises: The lift coefficient of the ground effect aircraft C L : , wherein, represents the reference lift coefficient at a fixed floor height; represents the change amount of the model height; represents the change amount of the wave height; represents the change amount of the wave height change rate; represents the derivative of the lift coefficient with respect to the model height; represents the derivative of the lift coefficient with respect to the wave height; represents the derivative of the lift coefficient with respect to the wave height change rate; C The roll moment coefficient l : , is the full cycle average value of the roll moment coefficient test data, is the difference between the lift coefficients of the left wing and the right wing, which can be obtained by the lift coefficient models of the left wing and the right wing, is the distance between the positions of the aerodynamic foci of the left wing and the right wing, is the wing span of the ground effect aircraft.

[0008] Further, in step 3, the aerodynamic model of the wing with boundary layer control is: where, is the aerodynamic parameter; is the reference value of the aerodynamic parameter in the current state; is the variation of the continuous variable; is the aerodynamic parameter of the continuous variable , which can be obtained by derivation of ; is the non-continuous variable; is the difference between the aerodynamic parameter corresponding to the variable and the reference value in the reference state .

[0009] Further, in step 4, the six-degree-of-freedom full-quantity dynamics equation is established under the aircraft body axis system, considering the influence of hydrodynamic force and hydrodynamic moment.

[0010] Further, in step 4, the wave height in the aerodynamic model of the full-quantity motion model is processed using the moving average method to replace the actual wave height at time with the average wave height below the wing in a period of time t –Δ t , t +Δ t . t .

[0011] Further, in step 4, the water surface force in the water surface force model includes buoyancy, hydrodynamic lift, hydrodynamic drag, hydrodynamic side force, water impact force when landing, hydrodynamic moment, and sea wave interference force.

[0012] Further, in step 4, the boundary layer control blowing model is: where, C μF0 , C μδe0 , C μδr0 is the rated blowing momentum coefficient; t blow is the delay time constant of the blowing system power link; t CμF is the delay time constant of the flap blowing transmission link; t ​​Cμδe The delay time constant of the elevator air transmission process; t Cμδr The delay time constant of the rudder air transmission link; d Cμδ For controlling the air volume of the elevator and rudder; d CμF This is the input for controlling the air volume of the flaps.

[0013] Furthermore, the linearized motion model of the ground effect aircraft in step 5 includes: a longitudinal linear model and a lateral linear model.

[0014] Furthermore, in step 2, the waves used in the active wave floor wind tunnel test are symmetrical waves.

[0015] Beneficial effects: This invention proposes a three-dimensional random ocean wave environment-based ground effect aircraft (GEA) motion modeling method. By combining ocean wave modeling, aerodynamic modeling, wind field modeling, and boundary layer control techniques, a comprehensive and accurate GEA motion model is established. This model can reflect the impact of ocean wave disturbances and boundary layer control on the motion characteristics of GEAs, providing an effective tool for flight control, mission simulation, and performance evaluation of GEAs in complex ocean wave environments. Specifically, this invention, through the Longuet-Higgins model and PM spectrum method, can realistically reproduce ocean waves of different wavelengths and amplitudes, accurately simulate the changes in wave height with space and time, and approximate the wave characteristics in the real ocean environment. This invention combines the influence of wind and wave environment, GEA aerodynamic model, and boundary layer control techniques, enabling a comprehensive evaluation of the impact of wind and wave environment on the water surface takeoff and landing and flight performance of GEAs. This invention, through a combination of active wave floor wind tunnel tests and numerical calculations, can better verify and adjust the model, reduce errors caused by experimental limitations, and improve the accuracy and reliability of the model. Attached Figure Description

[0016] Figure 1 This is a flowchart of the motion modeling process for ground effect aircraft in a three-dimensional random ocean wave environment.

[0017] Figure 2 This is a diagram of the three-dimensional atmospheric turbulence generation process in the Von Karman model.

[0018] Figure 3 This is a schematic diagram of the main parameters of the active wave floor.

[0019] Figure 4 This is a diagram illustrating the principle of ground effect in a wave environment.

[0020] Figure 5This is a structural diagram of the boundary layer control system for ground effect aircraft.

[0021] Figure 6 This is a diagram showing the average wave height below the wing. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0023] In the description of this invention, it should be understood that the terms "center", "axial", "vertical", "upper", "lower", "upper end", "bottom end", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0024] This invention relates to a method for modeling the motion of ground effect aircraft in a three-dimensional random ocean wave environment. More specifically, it is a method for modeling the motion of ground effect aircraft that couples ocean waves with aerodynamic effects and considers random wind and wave disturbances, based on the results of two-dimensional wave floor and boundary layer controlled wind tunnel tests.

[0025] To ensure the flight stability and safety of ground effect aircraft in complex sea conditions, this invention designs a ground effect aircraft motion modeling method that can reflect ocean waves, aerodynamic characteristics, boundary layer control and their interactions.

[0026] like Figure 1This invention discloses a method for modeling the motion of a ground effect aircraft (GEA) in a three-dimensional random ocean wave environment. First, a wind and wave environment model is established using an ocean wave model based on the wave spectrum and a classical atmospheric disturbance model. Second, an aerodynamic model of the GEA under wave conditions is established based on the results of active wave floor tests. Then, an aerodynamic model of the GEA with boundary layer control is established based on wind tunnel tests of the GEA with boundary layer control. Third, a full motion model of the GEA under a three-dimensional random ocean wave environment is established based on the GEA's dynamic equations, aerodynamic model, water surface force model, and boundary layer blowing model. Finally, small-disturbance linearization is performed on the full model to obtain a linearized motion model of the GEA considering atmospheric and wave disturbances. This invention solves the technical problem of establishing a motion model of a GEA under a three-dimensional random ocean wave environment, laying the foundation for the study of the motion characteristics of GEAs under wind and wave disturbances and the design of flight control laws.

[0027] The specific steps of the ground effect aircraft motion modeling method under a three-dimensional random ocean wave environment are as follows: (1) Establishment of wind and wave environment model The wave environment model consists of a wave model and a wind field model. This invention uses the Longuet-Higgins model based on the PM wave spectrum to establish a stochastic wave model. The Longuet-Higgins model, by superimposing multiple waveforms, can simulate complex wave environments and accurately reflect the spatiotemporal characteristics of waves. The choice of wave spectrum gives the wave model high computational efficiency, meeting the real-time requirements of simulation calculations.

[0028] The wind field model employs the classic atmospheric disturbance model—the Von Karman atmospheric turbulence model—to simulate the stability and flight control of ground effect aircraft in atmospheric disturbance environments. The model reflects the randomness and persistence of airflow, ensuring that the impact of wind randomness on aircraft flight quality is fully considered during sea-level flight.

[0029] (2) Aerodynamic modeling based on wind tunnel test of active wave floor The aerodynamic characteristics of ground effect vehicles (GEVs) need to consider the influence of wave surfaces and flight attitude. This invention studies the aerodynamic characteristics of GEVs in a wave environment using data from wind tunnel tests with an active wave floor. The active wave floor wind tunnel test, by simulating the relative motion of the aircraft in waves, reveals the influence of wave height and rate of change of height on aerodynamic parameters such as lift, drag, and torque of the GEV. Based on the results of the active wave floor wind tunnel test, this invention establishes an aerodynamic model of a GEV that considers the influence of wind and waves on aerodynamic parameters.

[0030] (3) Aerodynamic modeling based on wind tunnel test with boundary layer The boundary layer control system optimizes the aerodynamic characteristics of ground effect aircraft during low-speed water surface takeoff and landing through blown flap technology, increasing lift and improving maneuverability. Based on the influence of different flap blow volumes on lift and drag, this invention proposes an aerodynamic modeling method for ground effect aircraft with boundary layer control.

[0031] (4) Modeling of the full motion of ground effect aircraft The proposed method for establishing a full-scale motion model takes into account factors such as the aircraft's six degrees of freedom motion, aerodynamic characteristics, the influence of the boundary layer control system, and water surface forces. This model can realistically reflect the flight state of ground effect aircraft in complex wave and wind field environments, and is suitable for flight simulation and mission planning.

[0032] (5) Linearized motion modeling of ground effect aircraft Linearized motion models are suitable for small-disturbance analysis and are mainly used to analyze the handling and stability characteristics and flight control design of ground effect aircraft. This invention derives linearized models for the longitudinal and lateral directions by linearizing the six-degree-of-freedom motion equations of a ground effect aircraft. By considering the effects of atmospheric and wave disturbances in the linearized models, this invention can reflect the motion characteristics of ground effect aircraft under small-disturbance conditions.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings.

[0034] (1) Establishment of wind and wave environment model The wave model used in this invention is the Longuet-Higgins model. This model simulates random waves by linearly superimposing waveform functions based on the wave spectrum, thus representing waves as a superposition of a finite number of regular waves with different wavelengths and amplitudes. The Longuet-Higgins model treats waves as a height field, making it suitable for studying the impact of wave height variations on the aerodynamic characteristics of ground-effect aircraft. The three-dimensional form of the Longuet-Higgins wave model can be represented as follows: (1) h w This refers to the height of the ocean waves.

[0035] a ij Indicates the ( i , j The amplitude of the second harmonic.

[0036] k i This represents the wave number of the i-th harmonic.

[0037] q j Indicates the first j Direction angle of the subharmonic.

[0038] w i Indicates the first i The angular frequency of the subharmonic.

[0039] p ij Indicates the ( i , j The initial phase of the second harmonic.

[0040] x e , y e These are the coordinates in the sea surface coordinate system corresponding to the direction of the coastal waves.

[0041] in, p ij The phase can be randomly distributed within the period (0, 2π); k i Based on the relation Sure, g It is the acceleration due to gravity; a ij It can be obtained using the wave spectrum method. w i It is obtained by discretizing the wave frequency band. q j Through ~ It is obtained by discretization within the range.

[0042] The wave spectrum used in this invention is the PM spectrum (Pierson-Moskowitz spectrum), which is defined as: (2) U w The wind speed is at a height of 19.5m above sea level.

[0043] g is the acceleration due to gravity.

[0044] w Harmonic angular frequency, direction angle q .

[0045] .

[0046] .

[0047] According to the PM spectrum, the energy of ocean waves is concentrated within a narrow frequency range, approximately 0.25–4 rad / s; the influence of waves at other frequencies is negligible. w HAs the highest frequency in the wave frequency band. w L To be the lowest frequency, let w H = 4 rad / s, w L = 0.25 rad / s. Divide the frequencies within this band into... M Divided into equal parts, the corresponding frequency band width is . w i It can be defined as: (3) Direction angle q exist ~ The angles within the range are evenly distributed and divided into... N Divide into equal parts, each part corresponding to an angular width of... . q j It can be represented as: (4) According to the PM spectrum, ( w i , q j The corresponding amplitude can be expressed as: (5) w i Indicates the first i The angular frequency of the subharmonic.

[0048] q j Indicates the first j Direction angle of the subharmonic.

[0049] This indicates the bandwidth of each frequency band.

[0050] This indicates the width of each angle.

[0051] In summary, a Longuet-Higgins stochastic wave model based on the PM spectrum can be obtained.

[0052] The motion modeling, flight control design, and simulation research of ground effect aircraft mainly involves two types of wind field requirements: one is to examine the stability of ground effect aircraft in atmospheric disturbance environments and the performance of flight control systems, and the other is to examine the controllability and flight safety of ground effect aircraft when performing flight missions under adverse atmospheric conditions, such as water surface take-off and landing missions in crosswinds.

[0053] The wind field model used to examine the stability and flight control system performance of ground effect aircraft should possess characteristics such as persistence and stochasticity. An atmospheric turbulence model is suitable. Atmospheric turbulence models are typically established based on assumptions of stationarity and homogeneity, isotropy, Gaussian distribution, and a frozen field, utilizing stochastic processes and the spectral function of atmospheric turbulence to generate the turbulent field. The atmospheric turbulence model used in this invention is the Von Karman model, which uses three-dimensional bounded white noise (… n 1, n 2, n 3) Input a three-axis shaping filter based on the Von Karman spectrum to obtain the velocity components of atmospheric turbulence in the three axes in the sea surface coordinate system. u w , v w , w w ),like Figure 2 As shown. The intensity of atmospheric turbulence can be expressed using the root mean square error. s w 2 express, s w 2 It is mainly related to the average wind field intensity within the turbulent field and the altitude of the turbulent field. For the specific form of the Von Karman atmospheric turbulence model, please refer to the national military standards.

[0054] (2) Aerodynamic modeling based on wind tunnel test of active wave floor like Figure 3 The aerodynamic model of the ground effect aircraft in a wave environment is mainly established based on the results of wind tunnel tests on an active wave floor. Considering that the wave model used in the active wave floor test is a two-dimensional simple harmonic wave, in order to study the aerodynamic characteristics of the ground effect aircraft in a three-dimensional ocean wave environment, it is also necessary to consider the influence of factors such as asymmetric ocean waves and the flight attitude of the ground effect aircraft.

[0055] Based on the results of the active wave floor test, the lift coefficient of ground effect aircraft... C L It can be represented as: (6) This represents the baseline lift coefficient at a fixed floor height.

[0056] This indicates the change in the altitude of the aircraft model.

[0057] This indicates the change in wave height.

[0058] This represents the change in the rate of change of wave height.

[0059] This represents the derivative of the lift coefficient with respect to the model height.

[0060] This represents the derivative of the lift coefficient with respect to wave height.

[0061] This represents the derivative of the lift coefficient with respect to the rate of change of wave height.

[0062] In the active wave floor test, the aerodynamic characteristics of the aircraft model exhibited regular periodic changes. The calculation can be performed using a fixed floor height. In the cycle T Average value within: (7) This represents the lift coefficient.

[0063] T represents the period.

[0064] It represents the average value of the lift coefficient at a fixed floor height over a period of time.

[0065] and The calculation method is the same, but the values ​​are reversed. At a fixed floor height, the wave height... Periodic changes The impact is relatively small, therefore and The calculation is primarily based on the average value of test results at different floor installation heights. First, the calculations for different floor heights are performed. , , …corresponding , respectively represented as , , …。 Then through the Interpolation was performed to obtain the derivative of the lift coefficient with respect to the model height at different heights. and the derivative of the lift coefficient with respect to wave height : (8) This represents the m-th floor height from the test results.

[0066] This represents the nth floor height from the test results.

[0067] This represents the average lift coefficient over one cycle at the m-th floor height.

[0068] This represents the average lift coefficient over one cycle at the nth floor height.

[0069] The calculation can be performed using curve fitting. At a fixed floor height, Wave phase p The periodic variation basically conforms to the characteristics of a simple harmonic function. For calculation... A simple harmonic function needs to be used. The experimental data are fitted. The fitting function can take the following form: (9) This represents the average lift coefficient over one cycle.

[0070] The amplitude of the lift coefficient function.

[0071] This represents the initial phase of the lift coefficient function.

[0072] Due to the fixed floor height and right The impact is relatively small and can be approximated as... , From formulas 8 and 9, we can obtain: (10) This represents the derivative of the lift coefficient with respect to wave height.

[0073] This represents the change in the rate of change of wave height.

[0074] The amplitude of the lift coefficient function.

[0075] This represents the initial phase of the lift coefficient function.

[0076] Under different experimental conditions, Initial phase of the fitting result All are relatively small (not exceeding 25°), considering The change is a simple sine form. For ease of calculation, we can Initial phase of the fitting function Approximately 0. Ultimately, The calculation can be simplified to: (11) The amplitude of the lift coefficient function.

[0077] The amplitude is the amplitude of the high rate of change.

[0078] according to , , and The calculation results can be used to establish the lift coefficient of ground effect aircraft in wave environments. Aerodynamic model.

[0079] For aerodynamic parameters that are significantly affected by wave phase, such as drag coefficient Pitch moment coefficient Elevator control efficiency The same modeling method as the lift coefficient can be used for the following: take the average value of the full-cycle test results as the benchmark value, differentiate the full-cycle average value at different altitudes to obtain the derivative with respect to flight altitude and wave altitude, and perform curve fitting on the test results at different altitudes to obtain the derivative with respect to the rate of change of wave altitude.

[0080] For aerodynamic parameters that are not significantly affected by wave phase, such as the lateral heading coefficient, the corresponding reference parameters under different test conditions (such as relative height of the floor, aerodynamic angle, dynamic coefficient, etc.) can be obtained directly from the full-cycle average value of the test results. Then, the derivatives of the aerodynamic parameters with respect to flight state variables such as flight altitude, aerodynamic angle, and dynamic coefficient can be obtained by differentiation.

[0081] It is important to note that the active wave floor test used symmetrical waves, and the main state variables examined were the ground effect aircraft configuration, power configuration, control surfaces, and aerodynamic angles. The impact of asymmetrical three-dimensional random waves and flight attitude on the aerodynamic characteristics of the ground effect aircraft was not considered. In actual flight, asymmetrical waves on the left and right sides of the ground effect aircraft will generate additional aerodynamic forces and moments. Simultaneously, changes in aircraft attitude, especially roll attitude, will also affect its aerodynamic characteristics. Both asymmetrical waves and roll attitude angles will cause height differences between the left and right wings and the wave surface. The impact of the ground effect on the left and right wings differs, and the aerodynamic focus of the aircraft cannot be directly used as a reference point for aerodynamic characteristic calculations. Therefore, when calculating aerodynamic parameters significantly affected by the ground effect, such as the main longitudinal aerodynamic parameters, a method of calculating separately for the left and right wing focuses and then integrating them can be adopted. The aerodynamic models of the left and right wings are consistent in form with the full-aircraft aerodynamic model based on the test results, and the values ​​of various aerodynamic derivatives in the wing models can be taken as half of those in the full-aircraft model.

[0082] The roll moment coefficient, a key aerodynamic parameter in the lateral direction, is also affected by asymmetric waves and roll attitude. The lift difference caused by the height difference between the left and right wings introduces an additional roll moment. Therefore, the roll moment coefficient... Cl It can be represented as: (12) This represents the average value of the rolling moment coefficient test data over the entire cycle.

[0083] The difference between the lift coefficients of the left and right wings can be obtained through the lift coefficient model of the left and right wings.

[0084] The distance between the aerodynamic focal points of the left and right wings.

[0085] This is for the wingspan of ground effect aircraft.

[0086] It is evident that the longitudinal aerodynamic parameters of a ground effect vehicle (GEV) are influenced by the lateral state variables, and vice versa. This is a direct manifestation of the coupling between the longitudinal and lateral aerodynamic characteristics of a GEV. In the study of GEV motion modeling and control design, it is crucial to pay attention to the coupling between its longitudinal and lateral aerodynamic characteristics and its motion characteristics.

[0087] Apart from the main longitudinal aerodynamic parameters and the rolling moment coefficient, the calculation of other aerodynamic parameters of ground effect aircraft can still be carried out using an aerodynamic model based on the full-cycle average value of the test results.

[0088] (3) Aerodynamic modeling based on wind tunnel test with boundary layer This invention, based on wind tunnel test results of ground effect aircraft with boundary layer control, proposes an aerodynamic modeling method for ground effect aircraft with boundary layer control. The boundary layer control system of the ground effect aircraft employs blown flap technology, where a high-speed airflow is ejected tangentially to the upper surface of the wing at the trailing edge flap via a blown air device, causing the boundary layer to adhere to the flap surface. Because the high-pressure jet increases the energy contained in the boundary layer, it enhances the boundary layer's ability to overcome adverse pressure gradients, thereby effectively delaying airflow separation and increasing wing lift.

[0089] The boundary layer control system using blown flaps mainly consists of the following parts: Power unit: Provides power to the boundary layer control system. It can utilize the surplus power of the key engine or use a separate dedicated blowing engine. Compressor: Powered by a power unit, it generates a high-pressure air jet through impeller pressurization; Air blowing duct: guides the high-speed jet generated by the compressor to air blowing parts such as flaps and tail fin control surfaces; Air jet slit: High-speed jets are ejected along the upper surface of the air jet slit to achieve boundary layer control of the air jet slit; Control system: Based on the instructions of the pilot or flight control law, it realizes the opening / closing of the boundary layer control system and the adjustment of the blowing volume, etc.

[0090] The boundary layer control system structure of ground effect aircraft, such as Figure 5 As shown. The power plant employs a dedicated blown air engine integrated within the fuselage and connected in series with the compressor. Blown air ducts transmit the airflow generated by the compressor to the flaps, elevators, and rudder, and blown air onto the wing surfaces via blown air nozzles. The total blown air volume for the flaps and control surfaces is limited by the blown air engine's power and must be allocated based on the impact of the blown air volume on aerodynamic characteristics. The boundary layer control system's on / off commands and blown air volume adjustments are primarily issued by the pilot based on the operational requirements during water surface takeoff and landing. The flight control law is responsible for auxiliary functions such as matching the wing surfaces with the blown air volume based on the pilot's commands.

[0091] Compared to aerodynamic modeling based on active wave floor wind tunnel tests, aerodynamic modeling based on boundary layer controlled wind tunnel tests does not require consideration of external disturbance variables such as wave environment, but it does require consideration of more aircraft-specific state variables. State variables in boundary layer controlled wind tunnel tests include variables present in active wave floor tests such as aerodynamic angles and dynamic coefficients, as well as variables unique to boundary layer controlled tests such as blown momentum coefficients and flap / aileron configurations. State variables in the tests can be divided into two categories: continuous variables, such as aerodynamic angles, dynamic coefficients, and blown momentum coefficients; and discontinuous variables, such as spoiler states, flap / aileron states, and single-engine failure states. Aerodynamic modeling requires different modeling methods for the changes in different types of state variables based on the aerodynamic parameters.

[0092] The general form of aerodynamic parameters in wind tunnel tests with boundary layer control can be expressed as: (14) These are aerodynamic parameters.

[0093] These are the baseline values ​​for the aerodynamic parameters under the current conditions.

[0094] It represents the change in a continuous variable.

[0095] Aerodynamic parameters For continuous variables The derivative can be obtained through right Differentiating yields the result.

[0096] Let it be a non-continuous variable.

[0097] For variables Corresponding aerodynamic parameters Compared with the baseline state The difference.

[0098] The aerodynamic model of a ground effect aircraft based on a wind tunnel test with boundary layer can be established by using Equation (14).

[0099] (4) Establishment of the full motion model of ground effect aircraft The full motion model can reflect the longitudinal and lateral coupling characteristics of the aerodynamic properties of ground effect aircraft. The full motion model for water surface takeoff and landing controlled by boundary layer established in this invention consists of six-degree-of-freedom full dynamics and kinematic equations, an aerodynamic model, a water surface force model, and a boundary layer controlled blowing model.

[0100] First, a full motion model for controlling the rise and fall of the water surface with boundary layer is given, consisting of six-degree-of-freedom full dynamics and kinematic equations: The translational dynamics equations for water-based takeoff and landing with boundary layer control take into account the effects of hydrodynamics and are established under the aircraft body axis: (15) F w This refers to the forces exerted on an aircraft by the water surface when it is gliding on the water, including hydrodynamic forces and buoyancy.

[0101] m The mass of the ground effect aircraft.

[0102] g This is the acceleration due to gravity.

[0103] u , v , w These represent the components of the aircraft's inertial velocity in the three directions along the body axis.

[0104] p , q , r These represent the components of the aircraft's angular velocity in the three directions along the body axis.

[0105] L lift This indicates the aerodynamic lift force acting on the aircraft.

[0106] D This indicates the aerodynamic drag experienced by the machine.

[0107] C This indicates the aerodynamic lateral force acting on the body.

[0108] T It is the sum of the thrust of the propeller engine.

[0109] pT The mounting angle for the engine.

[0110] L ba This is the transformation matrix from the empty axis system to the body axis system.

[0111] L bg This is the transformation matrix from the Earth axis system to the body axis system.

[0112] The dynamic equation for take-off and landing on the water surface, taking into account the influence of hydrodynamic torque, can be expressed as: (16) M w This refers to the torque exerted by the water surface on an aircraft as it taxis, including the torque generated by hydrodynamic forces and buoyancy on the aircraft's center of mass.

[0113] I xx , I yy , I zz , I zx This represents the moment of inertia of a ground effect aircraft.

[0114] L, M, N These represent the three-axis aerodynamic torques acting on the aircraft.

[0115] L T 、M T 、N T These represent the three-axis torques generated by the engine, caused by factors such as engine eccentricity and unilateral engine failure.

[0116] p , q , r These represent the components of the aircraft's angular velocity in the three directions along the body axis.

[0117] , , These represent the components of the aircraft's angular acceleration in the three directions along the body axis.

[0118] The kinematic equations of ground effect aircraft include translational kinematic equations and rotational kinematic equations, which are used to describe the relationship between the motion of the aircraft in space and the speed and attitude of the aircraft, as shown in equations (16) to (17).

[0119] (17) (18) x g , y g , z g These are the coordinates of the ground effect aircraft's position in space.

[0120] f , q , p This refers to the aircraft's attitude angle.

[0121] p , q , r These represent the components of the aircraft's angular velocity in the three directions along the body axis.

[0122] u , v , w These represent the components of the aircraft's inertial velocity in the three directions along the body axis.

[0123] L gb This is the transformation matrix from the body axis to the earth axis.

[0124] In addition, parameters such as airspeed, ground speed, aerodynamic angle, and track angle of the ground effect aircraft need to be calculated. When atmospheric disturbances are present, the triangular relationship between airspeed, ground speed, and wind speed can be expressed as: (19) u a , v a , w a The components of airspeed in the three directions along the body axis.

[0125] x g , y g , z g These are the coordinates of the ground effect aircraft's position in space.

[0126] u w , v w , w w The components of wind speed in the three directions along the body axis.

[0127] L gb This is the transformation matrix from the body axis to the earth axis.

[0128] Further, airspeed can be obtained. V a and aerodynamic angle of attack α and sideslip angle β : (20) u a , v a , w a The components of airspeed in the three directions along the body axis.

[0129] Ground speed is the velocity of the center of mass in the Earth's axis frame. V g Track inclination g and track deflection c It can be represented as: (twenty one) , , These represent the velocity components of the ground effect aircraft in the three directions within the ground coordinate system.

[0130] Secondly, the method for establishing the aerodynamic model of the ground effect aircraft is presented. The aerodynamic model considering the influence of wind and wave environment is mainly obtained by referring to the aerodynamic modeling method based on active wave floor wind tunnel tests: (twenty two) p This refers to atmospheric density.

[0131] S This refers to the wing area.

[0132] c This is the longitudinal reference length, which is the average aerodynamic chord length of the wing.

[0133] b This is the lateral reference length, i.e., the wingspan.

[0134] Angle of attack.

[0135] It is the sideslip angle.

[0136] This represents the rate of change of angle of attack.

[0137] This is airspeed.

[0138] This is the lift coefficient.

[0139] This is the drag coefficient.

[0140] This is the lateral force coefficient.

[0141] This is the rolling torque coefficient.

[0142] This is the pitching moment coefficient.

[0143] This is the yaw moment coefficient.

[0144] p , q , r These represent the components of the aircraft's angular velocity in the three directions along the body axis.

[0145] This indicates the height of the difficult model.

[0146] Indicates wave height.

[0147] This represents the rate of change of wave height.

[0148] This refers to the elevator deflection angle.

[0149] This refers to the aileron deflection angle.

[0150] This refers to the rudder deflection angle.

[0151] flap Flange deflection Engine power coefficient The impact of wave models on aerodynamic characteristics is mainly reflected in wave height. and height change rate The influence of wind field models on aerodynamic characteristics is mainly reflected in the effect of atmospheric disturbances on aerodynamic angles. α and β The influence of configuration on aerodynamic models is mainly reflected in flap deflection. flap and engine power coefficient T c The influence of this. The longitudinal and lateral coupling of aerodynamic characteristics is mainly manifested in the roll attitude angle. f Changes in lift L lift ,resistance D Pitch moment M and rolling torque L The effects of flight altitude, wave height, and rate of change of altitude on the rolling moment. L The impact.

[0152] The aerodynamic and aerodynamic moment models for the boundary layer-controlled take-off and landing process are mainly based on the aerodynamic modeling methods of the boundary layer-controlled wind tunnel test: (twenty three) p This refers to atmospheric density.

[0153] S This refers to the wing area.

[0154] c This is the longitudinal reference length, which is the average aerodynamic chord length of the wing.

[0155] b This is the lateral reference length, i.e., the wingspan.

[0156] Angle of attack.

[0157] It is the sideslip angle.

[0158] This represents the rate of change of angle of attack.

[0159] This is airspeed.

[0160] This is the lift coefficient.

[0161] This is the drag coefficient.

[0162] This is the lateral force coefficient.

[0163] This is the rolling torque coefficient.

[0164] This is the pitching moment coefficient.

[0165] This is the yaw moment coefficient.

[0166] p , q , r These represent the components of the aircraft's angular velocity in the three directions along the body axis.

[0167] This indicates the height of the difficult model.

[0168] Indicates wave height.

[0169] This represents the rate of change of wave height.

[0170] This refers to the elevator deflection angle.

[0171] This refers to the aileron deflection angle.

[0172] This refers to the rudder deflection angle.

[0173] flap Flange deflection Engine power coefficient C μF , C μδe , C μδr These are the blowing momentum coefficients for the flaps, elevator, and rudder, respectively.

[0174] flap out The configuration state for the outer flaps as ailerons can be 20, 37.5, -20 or -37.5. A positive value indicates the deflection of the right outer flap (the left outer flap remains unchanged), and a negative value indicates the deflection of the left outer flap (the right outer flap remains unchanged).

[0175] SP (spoiler) indicates the spoiler status, which can be 0 or 1. 0 indicates that the spoiler is off, and 1 indicates that the spoiler is on.

[0176] EWS (engine working state) is the engine working state, which is a two-dimensional vector. The vector parameter can be 0 or 1. 1 indicates that the engine is working normally, and 0 indicates that the engine is malfunctioning. For example, [0, 1] indicates that the left engine is malfunctioning.

[0177] It is important to note that wave height and rate of change of height in aerodynamic models cannot be directly calculated using results from stochastic wave models. If high-frequency waves are directly used... and Incorporating aerodynamic models can lead to significant errors in calculation results, failing to accurately reflect the motion characteristics of ground effect aircraft.

[0178] This invention uses the moving average method to... and Processing will be carried out over a period of time ([ t –Δ t , t +Δ t Average wave height below the wing replace t Actual wave height at any given moment As in equation (23) and Figure 6 As shown. Through calculation This can transform rapidly fluctuating ocean waves into relatively uniformly changing waves, while essentially preserving the actual wave variation patterns, thus more accurately reflecting the impact of wave height on ground effect. Figure 4 .

[0179] (twenty four) Next, the method for establishing the water surface force model is given.

[0180] The surface forces acting on a ground effect aircraft during its water taxiing phase include buoyancy, hydrodynamic lift, hydrodynamic drag, hydrodynamic lateral forces, hydrodynamic impact force upon landing, hydrodynamic moment, and wave interference. The calculation of these surface forces can employ a semi-theoretical, semi-empirical engineering calculation method. Based on thin-wing theory and relevant theories of high-speed ship dynamics, a surface force model for the takeoff and landing process of a ground effect aircraft is established according to the force characteristics of the aircraft during its water taxiing phase.

[0181] The buoyancy of a ground effect aircraft during its water taxiing phase can be calculated using Archimedes' principle. During takeoff and landing, assuming that the density of water and the acceleration due to gravity remain constant, the calculation of buoyancy can be transformed into the calculation of the displacement volume: first, divide the fuselage along its length into multiple cross sections, then calculate the submerged area of ​​each cross section, and finally integrate the area of ​​the cross sections along the fuselage length to obtain the displacement volume, and thus the buoyancy experienced by the ground effect aircraft.

[0182] The hydrodynamic lift during the water taxiing phase can be simulated by abstracting the water-touch area of ​​the ground effect aircraft fuselage as a taxiing plate, using a two-dimensional thin wing model. Hydrodynamic lift is related to dynamic pressure, the wetted area of ​​the fuselage bottom, and the hydrodynamic lift coefficient, and its generation mechanism is similar to that of aerodynamic lift. The calculation formula for water dynamic pressure is basically the same as that for aerodynamic pressure. The calculation of the wetted area requires calculating parameters such as the average wetted length of the fuselage and the wetted aspect ratio based on the fuselage bottom configuration parameters and the aircraft attitude. The calculation of the hydrodynamic lift coefficient adopts the two-dimensional thin wing theory, and modifies the formula based on factors such as the influence of water viscosity on the lift line slope, the influence of lateral flow, and the angle of ascent at the aircraft bottom, combined with experimental data from the Central Aerodynamics and Hydrodynamics Research Institute of the Soviet Union. Finally, by combining the calculation results of water dynamic pressure, wetted area, and hydrodynamic lift, a hydrodynamic lift calculation model for the ground effect aircraft can be obtained.

[0183] Hydrodynamic drag during water taxiing includes frictional drag, viscous pressure drag, splash drag, and wave-making drag. Frictional drag is caused by the viscosity of water forming a boundary layer on the aircraft surface, resulting in viscous shear stress during taxiing. This frictional drag is related to the water viscosity, hull speed, hull length, wetted area, and coefficient of friction, and can be calculated using the formula for flat plate friction drag. Viscous pressure drag is caused by the viscosity of water consuming the kinetic energy of water particles, leading to an imbalance in water pressure before and after the aircraft's contact area; it is also known as form drag. Viscous pressure drag can be calculated using a three-dimensional transformation method, based on the proportional relationship between viscous pressure drag and frictional drag. Splash drag is the drag caused by water splashing during water taxiing, mainly related to the splash area and the splash drag coefficient. The splash area can be calculated based on the aircraft's dimensions and attitude, while the splash drag coefficient can be calculated based on the characteristic length of the splash area and the Reynolds number. Wave-making drag occurs because the aircraft generates waves as it glides on the water surface, causing changes in the pressure distribution on the aircraft's surface and creating a pressure difference between the bow and stern, thus generating drag. Wave-making drag can be calculated by referring to the wave-making drag data of a ship with a similar fuselage to the ground effect aircraft, and then estimating the wave-making drag of the ground effect aircraft based on that data.

[0184] The hydrodynamic lateral force is generated because the bottom of a ground effect aircraft has a lift angle. When the aircraft sideslips, a lateral force that opposes the aircraft's lateral movement is generated, which is the hydrodynamic lateral force. The hydrodynamic lateral force can be calculated based on the water pressure, the underwater projected area, and the lift angle.

[0185] Hydrodynamic impact force refers to the force generated when a ground effect aircraft lands on water and impacts the aircraft body. The magnitude of the hydrodynamic impact force is affected by factors such as the aircraft's weight and its distribution, the shape of the fuselage's bottom, the aircraft's pitch angle upon landing, and the landing speed. It can be calculated using the slice theory, which treats the landing impact force on the fuselage as the sum of the landing impact forces of countless wedge-shaped bodies. Through a series of assumptions and simplified calculations, a formula for calculating the hydrodynamic impact force is obtained.

[0186] Hydrodynamic torque comprises two parts: the torque directly generated by hydrodynamic forces and the hydrodynamic damping torque. The direct torque can be obtained by calculating the moments about the aircraft's center of gravity from buoyancy, hydrodynamic lift, hydrodynamic drag, hydrodynamic lateral forces, and hydrodynamic impact forces. The hydrodynamic damping torque is generated due to the aircraft's turning motion on the water surface and is mainly related to the aircraft's turning angular velocity and the three-axis hydrodynamic damping torque coefficients. The magnitude of the hydrodynamic damping torque can be obtained by calculating the aircraft's turning velocity and the hydrodynamic damping torque coefficients.

[0187] Ocean wave interference forces can generally be divided into two types: first-order wave interference forces, also known as high-frequency wave interference forces, are experienced by aircraft under the assumption that the waves are small-amplitude and cause minimal aircraft sway. These forces are linearly related to the wave height and have the same frequency as the waves, primarily causing pitch and heave motions, with relatively little impact on roll. Second-order wave forces, also known as wave drift forces, are proportional to the square of the wave height. This force is a nonlinear, low-frequency wave interference force that simultaneously alters the aircraft's heading and trajectory. Ground effect aircraft gliding on water are primarily subjected to first-order wave interference forces. The Froude-Krylov assumption can be used to calculate the distribution of water pressure on the aircraft's fuselage within the waves, and then the pressure changes caused by the waves can be integrated along the fuselage direction to obtain the wave interference force and torque.

[0188] Finally, a method for establishing a boundary layer controlled blowing model is presented.

[0189] Boundary layer control blowing model for ground effect aircraft, i.e., blowing momentum coefficient C μF , C μδe , C μδr Air volume control input d CμF , d Cμδ The response. Since the elevator and rudder share the same blowing pipe, the blowing volume control of both uses the same command. The boundary layer control blowing model consists of two parts: a power element consisting of a blowing engine and a compressor connected in series, and a transmission element consisting of a blowing pipe and a blowing nozzle, both of which can be simplified to first-order inertial elements. Therefore, the transfer function of the boundary layer control blowing model can be expressed as: (25) C μF0 , C μδe0 , C μδr0 The rated blowing momentum coefficient, C μF0 = 0.07, C μδe0 = 0.04, C μδr0 = 0.02.

[0190] t blow The time delay constant of the air blowing system's power component can be referenced from the engine's time delay characteristics. t blow = 2s.

[0191] t CμF The time delay constant for the flap air delivery process is mainly related to the airflow velocity and the length of the air delivery duct. Since the flap air delivery distance is relatively short, it can be taken as... t CμF = 1s.

[0192] t Cμδe The time constant for the air delivery process of the elevator is mainly related to the air delivery speed and the length of the air duct. The air delivery distances for the horizontal and vertical stabilizers are basically the same, so we can take [value missing]. t Cμδe = 2s.

[0193] t Cμδr The time constant for the rudder blow-through transmission process is given. The blow-through distances for the horizontal and vertical stabilizers are essentially the same, so we can take... t Cμδr = 2s.

[0194] d Cμδ This is the input for controlling the air volume of the elevator and rudder, limited to 0~1.

[0195] d CμF This is the input for controlling the air volume of the flaps, limited to 0~1.

[0196] (5) Establishment of linearized motion model for ground effect aircraft This invention establishes a linearized motion model for ground effect aircraft (GEA) based on classical flight mechanics theory and combined with a wind and wave environment model. The linearized motion model is obtained by linearizing the six-degree-of-freedom full motion equations under the assumption of small disturbances, including a longitudinal linear model and a lateral linear model. The linearized motion model can reflect the frequency domain motion characteristics of GEA and is mainly used in this paper for the analysis of GEA handling and stability characteristics and flight control design research.

[0197] The linearized motion model can be represented in the form of state equations: (26) x This is the state vector.

[0198] It is the derivative of the state vector.

[0199] u For manipulating variables.

[0200] w This is a disturbance variable.

[0201] A Let be the state matrix of the system.

[0202] B u This is the system manipulation matrix.

[0203] B w Let be the perturbation matrix of the system.

[0204] The longitudinal linear motion model of a ground effect aircraft in a windy and wavey environment is as follows: (27) For the state variables of the aircraft motion, it represents the changes in flight speed, angle of attack, pitch rate, pitch attitude angle and flight altitude.

[0205] These are the manipulated variables, representing the changes in elevator deflection angle and throttle.

[0206] For atmospheric disturbance variables, it represents the changes in the horizontal and vertical components of atmospheric disturbance in the empty axis frame.

[0207] For wave disturbance variables, represent the changes in the moving average wave height and the rate of change of wave height; , , These are the dynamic derivatives, the derivatives of the aerodynamic coefficients, and the derivatives of the engine thrust. , , , Related to...

[0208] This is the acceleration due to gravity.

[0209] This is the airspeed under baseline conditions.

[0210] In the longitudinal linear motion model, the aerodynamic derivatives affected by the ground effect are mainly: , , , , , , , and .in, , , The aerodynamic coefficient is the factor relating the aircraft's flight altitude to sea level. h The derivative of is reflected in the vertical state matrix.

[0211] , , Aerodynamic coefficient versus wave height The derivative of .

[0212] , , The aerodynamic coefficient is the rate of change of wave height. The derivative of the aerodynamic coefficient with respect to wave height and flight altitude has an effect reflected in the wave disturbance matrix. Under the small disturbance assumption, the derivatives of the aerodynamic coefficient with respect to wave height and flight altitude are opposites. (Flight altitude change rate) The effect on the aerodynamic coefficient is already reflected in the derivative with respect to the angle of attack, so it does not need to be considered separately.

[0213] The lateral linear motion model of a ground effect aircraft in a windy and wavey environment is as follows: (28) For the state variables of the aircraft motion, it represents the changes in sideslip angle, roll angular velocity, yaw angular velocity, and roll attitude angle.

[0214] For manipulation variables, represent the changes in aileron deflection and rudder deflection; .

[0215] , where is the atmospheric disturbance variable, representing the change in the lateral component of the atmospheric disturbance in the empty axis frame; .

[0216] The wave disturbance variable represents the change in the difference between the moving average wave height and the rate of change of height below the left and right wings.

[0217] , , The derivatives are kinetic derivatives and aerodynamic coefficient derivatives. , , Related to...

[0218] This is the acceleration due to gravity.

[0219] , α 0、 q 0 represents the airspeed, angle of attack, and pitch angle at the baseline.

[0220] In the lateral linear motion model, the derivatives of the aerodynamic coefficients affected by ground effect are mainly: , and , respectively representing the rolling moment coefficient with respect to the rolling attitude angle f The difference in wave height under the left and right wings Difference between the rate of change of height The derivative of . The effect is reflected in the lateral state matrix. and The impact is reflected in the wave disturbance matrix.

[0221] The linearized motion model for water surface takeoff and landing with boundary layer control is mainly for the state of ground effect aircraft flying close to the water surface for trim, so the influence of water surface forces can be ignored. In the modeling process, the relevant parameters of the boundary layer control system can be taken as fixed values, and the dynamic derivatives of the boundary layer control system parameters do not need to be considered. The form of the model is basically the same as that of equations (27) and (28).

[0222] In summary, the method of this invention constructs a wave environment model suitable for ground effect aircraft by combining the Longuet-Higgins wave model with the PM wave spectrum. In this model, wave characteristics are formed by waveform superposition to simulate a random wave environment. Furthermore, the influence of boundary layer control technology on the aerodynamic characteristics of ground effect aircraft is considered in the wind and wave environment. By considering the relationship between wave frequency and wind speed, this method ensures that the simulation results closely approximate the real wave environment.

[0223] The described wave environment model adopts a three-dimensional form of the Longuet-Higgins model. This model forms a wave height field by superimposing multiple harmonics, thereby describing the spatial and temporal variation characteristics of waves and simulating waves with different wavelengths and amplitudes. The model achieves simulation of complex wave environments by controlling the frequency range and azimuth angle distribution of the waves.

[0224] The aerodynamic model of a ground effect vehicle (GEV) in wind and wave environments utilizes data from wind tunnel tests on an active wave floor, including aerodynamic parameters such as the lift coefficient of the GEV considering the influence of wind and waves. This model can reflect the aerodynamic characteristics of the GEV under different wave and wind speed conditions by adjusting parameters such as the speed of the active wave floor, wave phase, and the relative altitude of the aircraft.

[0225] This model is used to simulate the motion of ground effect aircraft in random ocean wave environments. It combines the calculation of wind and wave environment, aerodynamic characteristics of ground effect aircraft and water surface forces, and considers the influence of boundary layer control technology on the water surface take-off and landing process of ground effect aircraft. It can calculate water surface forces through a semi-theoretical and semi-empirical method and can be applied to fields such as water surface take-off and landing, safety assessment and flight control design.

[0226] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for modeling the motion of ground-effect aircraft in a three-dimensional random ocean wave environment, characterized in that, include: Step 1: Establish a wind and wave environment model, which includes a wave model and a wind field model; Step 2: Based on the wave model, establish an aerodynamic model of the ground effect aircraft under wave environment based on the wind tunnel test results of the active wave floor of the ground effect aircraft; Step 3: Establish an aerodynamic model of a ground effect aircraft with boundary layer control based on wind tunnel tests of ground effect aircraft with boundary layer control; Step 4: Based on the aerodynamic model of the ground effect aircraft in the wave environment and the aerodynamic model of the ground effect aircraft with boundary layer control, establish the full motion model of the ground effect aircraft in the three-dimensional random wave environment. The full motion model includes: six-degree-of-freedom full dynamics and kinematic equations, aerodynamic model, water surface force model, and boundary layer control blowing model. Step 5: Perform small-perturbation linearization on the full model to obtain a linearized motion model of the ground effect aircraft that takes into account atmospheric disturbances and wave disturbances.

2. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 1, characterized in that, In step 1, the wave model is a stochastic wave model based on the Longuet-Higgins model of the PM wave spectrum, and the wind field model is the Von Karman atmospheric turbulence model.

3. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 2, characterized in that, In step 2, the aerodynamic model of the ground effect aircraft in a wave environment includes: Lift coefficient of ground effect aircraft C L : ,in, This represents the baseline lift coefficient at a fixed floor height. This indicates the change in the altitude of the aircraft model; This indicates the change in wave height; This represents the change in the rate of change of wave height; This represents the derivative of the lift coefficient with respect to the model height; This represents the derivative of the lift coefficient with respect to wave height; This represents the derivative of the lift coefficient with respect to the rate of change of wave height; Rolling torque coefficient C l : , The rolling moment coefficient is the average value of the test data over the entire cycle. The difference between the lift coefficients of the left and right wings can be obtained using the lift coefficient models for the left and right wings. The distance between the aerodynamic focal points of the left and right wings. This is for the wingspan of ground effect aircraft.

4. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 3, characterized in that, In step 3, the aerodynamic model of the ground effect aircraft with boundary layer control is as follows: ,in, These are aerodynamic parameters; These are the baseline values ​​for the aerodynamic parameters under the current conditions. The change in a continuous variable; Aerodynamic parameters For continuous variables The derivative can be obtained through right Differentiation yields; Let it be a non-continuous variable; For variables Corresponding aerodynamic parameters Compared with the baseline state The difference.

5. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 4, characterized in that, In step 4, the six-degree-of-freedom full dynamic equations are established under the aircraft body axis, taking into account the effects of hydrodynamics and hydrodynamic torque.

6. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 5, characterized in that, In step 4, the wave height of the aerodynamic model in the full motion model is calculated using the moving average method. Processing will be carried out over a period of time ([ t –Δ t , t +Δ t Average wave height below the wing replace t Actual wave height at any given moment .

7. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 6, characterized in that, In step 4, the surface forces in the water surface force model include buoyancy, hydrodynamic lift, hydrodynamic resistance, hydrodynamic lateral force, hydrodynamic impact force upon contact with water, hydrodynamic torque, and wave disturbance force.

8. The method for modeling ground effect aircraft motion in a 3D random wave environment according to claim 7, characterized in that, In step 4, the boundary layer controlled blowing model is as follows: ,in, C μF0 , C μδe0 , C μδr0 This is the rated blowing momentum coefficient; τ blow The time delay constant of the power element in the air blowing system; τ CμF This is the time delay constant for the flap air transmission process; τ Cμδe The delay time constant of the elevator air transmission process; τ Cμδr The delay time constant of the rudder air transmission link; δ Cμδ For controlling the air volume of the elevator and rudder; δ CμF This is the input for controlling the air volume of the flaps.

9. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 8, characterized in that, The linearized motion model for the ground effect aircraft in step 5 includes: a longitudinal linear model and a lateral linear model.

10. The method for modeling ground effect aircraft motion in a 3D random ocean wave environment according to claim 9, characterized in that, In step 2, the waves used in the active wave floor wind tunnel test are symmetrical waves.

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