Seaplane take-off and landing process dynamics calculation method and system suitable for high sea conditions

Abstract

The invention provides a seaplane take-off and landing process dynamics calculation method and system suitable for high sea conditions, and the method comprises the steps: obtaining the hydrodynamic test data of a ship-shaped fuselage at the bottom of a seaplane in real time, and building a body coordinate system and a ground coordinate system; then establishing a height compensation model and an attitude compensation model based on the wave height to obtain a vertical distance and a pitch angle after wave influence correction, and calculating the infiltration area after wave influence at the current moment by adopting a specific calculation method; and finally, introducing the infiltration area influenced by waves on the basis of a total motion equation consisting of a centroid kinetic equation, a centroid kinematical equation, a rotation kinetic equation and a rotation kinematical equation, so as to establish an improved centroid kinetic equation, an improved centroid kinematical equation, an improved rotation kinetic equation and an improved rotation kinematical equation. Therefore, the real-time dynamic analysis of the take-off and landing process of the seaplane under the high sea condition is realized, and the method has remarkable rapidity, real-time performance and accuracy.

Description

Technical Field

[0001] This invention relates to the field of aerospace engineering technology, specifically to a dynamic calculation method and system for the take-off and landing process of seaplanes adapted to high sea states. Background Technology

[0002] As an aircraft capable of taking off and landing on water, the design of seaplanes requires consideration not only of aerodynamic performance but also, and more importantly, of the hydrodynamic performance of the hull. This is because seaplanes are affected by various factors such as wind, waves, and currents during takeoff and landing, which significantly impact their motion stability, structural strength, and hydrodynamic performance. To ensure the safe takeoff and landing of seaplanes under various sea conditions, researchers have conducted extensive studies, primarily focusing on the following aspects: 1) Hydrodynamic testing: Traditional research methods rely mainly on hydrodynamic testing, simulating the water surface taxiing and takeoff / landing processes under different sea conditions to study the aircraft's hydrodynamic performance, motion stability, and structural strength. While these tests provide relatively accurate data, they are extremely costly in terms of financial and material resources and have long testing cycles. 2) Computational fluid dynamics (CFD) methods: With the development of computer technology, CFD methods have gradually become an important tool for studying the hydrodynamic performance of seaplanes. CFD methods can accurately calculate the hydrodynamic performance of aircraft under different sea conditions through numerical simulation. However, CFD methods are time-consuming and require substantial computational resources, making it difficult to meet the real-time computational requirements of flight simulations. 3) Low Sea State Studies: Currently, there is considerable research on the takeoff and landing performance of seaplanes in low sea states, and related models and algorithms are relatively mature. These studies provide theoretical support for the safe takeoff and landing of seaplanes in calm sea states. However, previous discussions on the wetting area in seaplane dynamics models often approximate the water surface as calm. This assumption is appropriate in low sea states because the influence of waves is small and negligible. 4) High Sea State Studies: However, research on the takeoff and landing performance of seaplanes in high sea states remains insufficient. Environmental factors such as wind, waves, and currents are more complex in high sea states, placing higher demands on the hydrodynamic performance and motion stability of the aircraft. Existing hydrodynamic tests and CFD methods have limited applicability in high sea states and cannot meet the needs of real-time calculations. Especially in high sea states, wave crests and wavelengths are large and cannot be ignored even at the aircraft scale. Therefore, the traditional approximation method based on calm water surface is no longer applicable in high sea states. It is necessary to dynamically calculate the aircraft's wetted area in combination with wave conditions to more accurately reflect the aircraft's hydrodynamic characteristics in high sea states.

[0003] Therefore, while existing research methods have solved the takeoff and landing problems of seaplanes in low sea states to some extent, they still have the following shortcomings: 1) High cost and low efficiency: Hydrodynamic testing consumes a lot of financial and material resources and has a long testing cycle, making it difficult to meet the requirements of high efficiency and low cost in the pre-research process of aircraft design. 2) High computational resource requirements: Although CFD methods can provide accurate calculation results, the calculation time is long and requires a lot of computational resources, making it difficult to meet the real-time requirements of flight simulation. 3) Insufficient adaptability to high sea states: Existing research mainly focuses on low sea states, and there is insufficient research on the takeoff and landing performance of seaplanes in high sea states. There is a lack of dynamic models and real-time solution methods adapted to high sea states. In particular, the static approximation of the wetting area in traditional models is no longer applicable in high sea states, and the failure to consider the wave effects in high sea states leads to a decrease in model accuracy.

[0004] In view of the above problems, there is an urgent need for a real-time solution method for seaplane dynamics models adapted to sea state 5. This method should take into account the wave effects under high sea states, and improve computational efficiency while ensuring computational accuracy and reducing computational resource requirements, so as to meet the real-time requirements of flight simulation. At the same time, the method should also have high sea state adaptability, be able to cope with the defense needs under complex sea states, and enhance national defense capabilities. Summary of the Invention

[0005] This invention addresses the problems in current analyses of seaplane takeoff and landing processes, such as decreased accuracy due to the lack of consideration for wave effects in high sea states, narrow applicability, slow calculation speed, and poor real-time performance. It provides a dynamic calculation method for seaplane takeoff and landing processes adapted to high sea states, which can accurately calculate the wetted area of ​​the seaplane, improving calculation accuracy and efficiency, and exhibiting significant speed, real-time performance, and accuracy. This invention also relates to a dynamic calculation system for seaplane takeoff and landing processes adapted to high sea states.

[0006] The technical solution of the present invention is as follows:

[0007] A dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states, characterized by the following steps:

[0008] Data acquisition steps: Real-time acquisition of hydrodynamic test data of the bottom hull of the seaplane, including wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull.

[0009] Altitude and attitude correction steps: Establish a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. Obtain the coordinates of the aircraft's center of mass in the ground coordinate system. Based on the abscissa of the center of mass coordinates and the wave height at the current moment, establish an altitude compensation model and an attitude compensation model respectively. Input the vertical distance from the current step point to the horizontal plane into the altitude compensation model to obtain the vertical distance after wave correction. Input the current pitch angle of the seaplane into the attitude compensation model to obtain the pitch angle after wave correction.

[0010] Steps for calculating the wetted area: Calculate the keelline wetted length of the seaplane based on the corrected pitch angle and corrected vertical distance; calculate the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull tilt angle, and pitch angle; calculate the average fuselage wetted length based on the keelline and bilgeline wetted lengths; calculate the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; correct the fuselage wetted aspect ratio using an empirical formula based on hydrodynamic test data; and calculate the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width.

[0011] Real-time analysis steps for takeoff and landing: Based on the total motion equation consisting of the center of mass dynamics equation, the center of mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation, the wetted area after wave influence is introduced to update the original wetted area without wave influence in the total motion equation, thereby obtaining the updated total motion equation. Based on the updated total motion equation, the flight state parameters are calculated to realize real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

[0012] Preferably, a body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis. The flight state parameters include the aircraft's linear velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, the aircraft's angular velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, and the aircraft's center of mass position, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the ground coordinate system.

[0013] Preferably, in the real-time analysis step of the takeoff and landing process, the calculation of flight state parameters based on the updated full motion equations specifically includes: calculating the aircraft's center of mass position in the longitudinal, lateral, and vertical axes in the ground coordinate system, and the aircraft's linear velocity and angular velocity, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the body coordinate system based on the updated center of mass dynamics equation, center of mass kinematics equation, rotational dynamics equation, and rotational kinematics equation coupled together.

[0014] Preferably, a real-time feedback control algorithm is used to optimize the calculated flight state parameters to obtain optimized flight state parameters, so as to realize real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states.

[0015] A dynamic calculation system for the takeoff and landing process of a seaplane adapted to high sea states is characterized by comprising a data acquisition module, an altitude and attitude correction module, a wetted area calculation module, and a real-time analysis module for the takeoff and landing process, connected in sequence.

[0016] The data acquisition module acquires hydrodynamic test data of the bottom hull of the seaplane in real time. The hydrodynamic test data includes wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull.

[0017] The altitude and attitude correction module establishes a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. It then obtains the coordinates of the aircraft's center of mass in the ground coordinate system. Based on the abscissa of the center of mass coordinates and the wave height at the current moment, it establishes an altitude compensation model and an attitude compensation model, respectively. The vertical distance from the current step point to the horizontal plane is input into the altitude compensation model to obtain the vertical distance after wave correction. The pitch angle of the seaplane at the current moment is input into the attitude compensation model to obtain the pitch angle after wave correction.

[0018] The wetted area calculation module calculates the keelline wetted length of the seaplane based on the corrected pitch angle and the corrected vertical distance; it then calculates the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull lift angle, and pitch angle; it calculates the average fuselage wetted length based on the keelline wetted length and bilge wetted length; it then calculates the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; and it corrects the fuselage wetted aspect ratio using an empirical formula method based on hydrodynamic test data to obtain the corrected wetted aspect ratio. Finally, it calculates the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width.

[0019] The real-time analysis module for takeoff and landing processes introduces the wetted area affected by waves into the total motion equation, which is composed of the center of mass dynamics equation, the center of mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation. This updates the original wetted area unaffected by waves in the total motion equation, thereby obtaining the updated total motion equation. Based on the updated total motion equation, the module calculates the flight state parameters to achieve real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

[0020] Preferably, a body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis. The flight state parameters include the aircraft's linear velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, the aircraft's angular velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, and the aircraft's center of mass position, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the ground coordinate system.

[0021] Preferably, in the real-time analysis module for takeoff and landing, the calculation of flight state parameters based on the updated full equation of motion specifically includes: calculating the aircraft's center of mass position in the longitudinal, lateral, and vertical axes in the ground coordinate system, and the aircraft's linear velocity and angular velocity, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the body coordinate system based on the updated center of mass dynamics equation, center of mass kinematics equation, rotational dynamics equation, and rotational kinematics equation coupled together.

[0022] Preferably, a real-time feedback control algorithm is used to optimize the flight state parameters to obtain optimized flight state parameters, so as to realize real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention provides a dynamic calculation method for the take-off and landing process of seaplanes adapted to high sea states. First, hydrodynamic test data of the seaplane's bottom hull shape is acquired in real time and a ground coordinate system is established. Then, based on the wave height and the horizontal coordinate in the centroid coordinate system at the current moment, a height compensation model and an attitude compensation model are established respectively, thereby obtaining the corrected vertical distance and pitch angle. By considering the influence of wave height on the take-off and landing of seaplanes under high sea states, the vertical distance (i.e., aircraft height) and pitch angle (attitude) are adjusted in real time to ensure that the aircraft can maintain a stable flight state on the undulating sea surface under high sea states. Then, a specific calculation method was used to calculate the wetted aspect ratio of the fuselage. An empirical formula based on hydrodynamic test data was then used to correct the wetted aspect ratio, resulting in a corrected wetted aspect ratio. This correction using an empirical formula based on hydrodynamic test data compensated for the difference between theoretical calculations and actual conditions, making the results closer to reality and enhancing the accuracy and reliability of the calculations. Based on the corrected wetted aspect ratio and bilge width, the wetted area of ​​the seaplane after being affected by waves at the current moment was calculated, achieving an accurate description of the aircraft's wetted characteristics under high sea states, providing key input for flight state analysis and takeoff and landing process simulation. Finally, the wetted area was calculated using the center of mass dynamics equations and the center of mass motion equations. Based on the total equation of motion, which consists of the kinetic equation, rotational dynamics equation, and rotational kinematics equation, the wetted area after wave influence is introduced to update the original wetted area without wave influence in the total equation of motion, thus obtaining an updated total equation of motion. Flight state parameters are calculated based on the updated total equation of motion to achieve real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states. This invention describes the aircraft dynamics process by using an improved total equation with higher accuracy and nonlinearity to more accurately capture the dynamic characteristics under complex sea states, significantly improving the ability to evaluate aircraft performance and safety in extreme environments, and providing reliable support for flight operations and decision-making.

[0025] This invention also relates to a dynamic calculation system for the take-off and landing process of seaplanes adapted to high sea states. This system corresponds to the aforementioned dynamic calculation method for the take-off and landing process of seaplanes adapted to high sea states. It can be understood as a system that implements the aforementioned dynamic calculation method for the take-off and landing process of seaplanes adapted to high sea states. The system includes a data acquisition module, an altitude and attitude correction module, an immersion area calculation module, and a real-time analysis module for the take-off and landing process, which are connected in sequence. The modules work together to establish an altitude compensation model and an attitude compensation model, thereby obtaining the corrected vertical distance and pitch angle. The system comprehensively considers the influence of waves on the motion and attitude of seaplanes under high sea states, thereby ensuring that the aircraft can maintain a stable flight state on the undulating sea surface under high sea states. Furthermore, the system uses an improved full equation with higher accuracy and nonlinearity to describe the aircraft dynamic process, so as to more accurately capture the dynamic characteristics under complex sea states, greatly improve the calculation accuracy, and effectively improve the calculation efficiency. It has significant speed, real-time performance, and accuracy. Attached Figure Description

[0026] Figure 1 This is a flowchart of the dynamic calculation method for the take-off and landing process of seaplanes adapted to high sea states, as described in this invention.

[0027] Figure 2 This is a schematic diagram of the body coordinate system.

[0028] Figure 3 This is a schematic diagram of the ground coordinate system.

[0029] Figure 4 This is a schematic diagram of the bottom configuration parameters of the seaplane's fuselage.

[0030] Figure 5 This is a schematic diagram for calculating the aspect ratio of the immersion material.

[0031] Figure 6 and Figure 7 This is a schematic diagram of the takeoff process of a seaplane in sea state 5.

[0032] Figure 8 and Figure 9 This is a schematic diagram of the seaplane landing process under sea state 5. Detailed Implementation

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

[0034] This invention relates to a dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states. The flowchart of the method is as follows: Figure 1 As shown, the steps are as follows:

[0035] 1. Real-time acquisition of hydrodynamic test data of the bottom hull of the seaplane, including wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull.

[0036] II. Altitude and Attitude Correction Steps: Establish a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. Obtain the coordinates of the aircraft's center of mass in the ground coordinate system. Based on the abscissa of the center of mass coordinates and the wave height at the current moment, establish an altitude compensation model and an attitude compensation model respectively. Input the vertical distance from the current step point to the horizontal plane into the altitude compensation model to obtain the vertical distance after wave correction. Input the current pitch angle of the seaplane into the attitude compensation model to obtain the pitch angle after wave correction.

[0037] Specifically, a ground coordinate system is established with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis; a body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis; and the coordinates of the aircraft's center of mass located in the ground coordinate system are obtained.

[0038] Ground coordinate system like Figure 2 As shown, this is a fixed inertial coordinate system anchored to the ground, used to describe the position, attitude, and velocity direction of the aircraft's center of mass. The origin of the coordinate system is... We can take any point on sea level, with the Earth's center as the vertical axis, that is... The axis points towards the Earth's center; the aircraft's initial direction of motion is the longitudinal axis, i.e. The direction pointing to the initial direction of the aircraft's motion; the direction on the aircraft's starboard side, parallel to the sea level, is the lateral axis, i.e. The axis points to the starboard side of the aircraft and is parallel to the sea level. The axes are located within the sea level and are perpendicular to each other, and the distribution of the three coordinate axes conforms to the right-hand rule.

[0039] Body coordinate system ,like Figure 3 As shown, this is a motion coordinate system fixed to the aircraft body, used to describe the motion state of the aircraft body. The origin of the coordinate system is... The center of mass of the aircraft is the longitudinal axis, and the direction of the aircraft's nose is the longitudinal axis. ,Right now The longitudinal axis coincides with the aircraft's longitudinal axis (pointing from the nose to the tail; rotation around this axis is called pitch, i.e., the aircraft's upward or downward movement) and points towards the nose; the direction on the aircraft's starboard side is the lateral axis. ,Right now The vertical axis aligns with the aircraft's lateral axis (pointing from the left wingtip to the right wingtip; rotation around this axis is called roll, the motion of one wing rising while the other descends) and points towards the right side of the aircraft; the direction of the aircraft's bottom is the vertical axis. ,Right now The axis coincides with the aircraft's vertical axis (perpendicular to the fuselage, usually pointing downwards (negative direction). Rotation around this axis is called yaw motion, which is the movement of the aircraft's nose turning left and right) and points towards the bottom of the boat-shaped fuselage.

[0040] Then, since existing models generally approximate the water surface as calm, this approximation is feasible under low sea states, but under high sea states, the larger wave crests and wavelengths introduce significant errors, which are not negligible even at the aircraft scale. This invention dynamically calculates the aircraft's wetted area by combining wave conditions, fully considering the impact of waves on the aircraft's hydrodynamic performance under high sea states. Specifically, a height compensation model and an attitude compensation model are first established based on the horizontal coordinate in the centroid coordinate system (i.e., the aircraft's chordal position) and the current wave height. The vertical distance from the current step point to the horizontal plane is input into the height compensation model to obtain the vertical distance corrected for wave effects. The height compensation model is shown in the following equation:

[0041] (1)

[0042] in, This is the vertical distance after correction for wave effects; It is the vertical distance from the current step break point to the horizontal plane, which can also be called the aircraft altitude or the aircraft's center of gravity altitude; Wave height It is the x-coordinate in the centroid coordinate system (i.e., the chordal position of the aircraft). This indicates the wave height at the chord position of the seaplane.

[0043] The current pitch angle of the seaplane is then input into the attitude compensation model to obtain the pitch angle after wave correction. The attitude compensation model is shown in the following equation:

[0044] (2)

[0045] in, The pitch angle is corrected for wave effects; The pitch angle of the seaplane at the current moment.

[0046] By establishing altitude compensation and attitude compensation models, the corrected vertical distance and pitch angle are obtained, enabling real-time correction of aircraft altitude and attitude at every moment. This significantly improves speed and real-time performance, effectively enhancing calculation accuracy. Furthermore, the impact of waves in high sea states (preferably sea state 5) on the motion and attitude of seaplanes is fully considered, ensuring that the aircraft can maintain stable flight on undulating sea surfaces in high sea states.

[0047] III. Steps for calculating the wetted area: Calculate the keelline wetted length of the seaplane based on the corrected pitch angle and corrected vertical distance; calculate the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull tilt angle, and pitch angle; calculate the average fuselage wetted length based on the keelline and bilgeline wetted lengths; calculate the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; correct the fuselage wetted aspect ratio using an empirical formula method based on hydrodynamic test data to obtain the corrected wetted aspect ratio; calculate the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width.

[0048] Specifically, such as Figure 4 As shown, when gliding on water, the water spray from the nose section of the seaplane increases the wetted length and wetted area. The keelline wetted length of the seaplane is first calculated based on the corrected pitch angle and corrected vertical distance. Calculate according to the following formula:

[0049] (3)

[0050] in, The vertical distance from the break point of the corrected hull to the horizontal plane; The pitch angle.

[0051] when When this happens, it will cause the keel line wetting length to become negative; when When the value is close to 0, the keel line wetting length can become a very large positive or negative value, which is inconsistent with reality. Therefore, there are limitations when using the formula. .

[0052] Then, based on the keel line wetted length, bilge beam, hull heave angle, and pitch angle, the bilge line wetted length of the fuselage is calculated. The calculation formula is:

[0053] (4)

[0054] in, For the bilge of the ship-shaped fuselage; The hull's lift angle; For pitch angle, when This will cause the bilge line wetted length to be greater than the keel line wetted length; when When the value is close to 0, it can cause the second term on the right side of the equation to have a large negative or positive value, resulting in the bilge line being much larger than the keel line wetted length or less than 0. This is inconsistent with reality. There are also limitations when using the formula. .

[0055] The average wetted length of the fuselage was calculated based on the wetted lengths of the keel line and bilge line. Calculate according to the following formula:

[0056] (5)

[0057] Ignoring splashing, the aspect ratio of the fuselage wetted is calculated based on the average wetted length and bilge width. Calculate according to the following formula:

[0058] (6)

[0059] When a seaplane glides on the water, the water surface becomes more wetted due to splashing, such as... Figure 5 As shown, assuming that the aspect ratio of the wetted area increases due to splashing. Therefore, Savitsky corrected the wetted aspect ratio based on a large number of hydrodynamic tests, and used an empirical formula method based on hydrodynamic test data to correct the wetted aspect ratio of the fuselage, thus obtaining the corrected wetted aspect ratio. , and The following relationship exists:

[0060] (7)

[0061] Savitsky believes that the applicable scope of the above-mentioned immersion length calculation and the applicable scope of the immersion aspect ratio correction method are as follows: , , .in, For drainage volume, For speed coefficient, The average water flow velocity at the bottom of the aircraft. It represents the acceleration due to gravity.

[0062] In summary, the wetted area of ​​the seaplane after being affected by waves at the current moment was calculated based on the corrected wetted aspect ratio and bilge width. The expression for the wetting area is:

[0063] (8)

[0064] in, The bilge width of the ship-shaped fuselage.

[0065] By calculating the contact area between the aircraft fuselage and the waves in real time, i.e. the wetting area, the hydrodynamic characteristics of the aircraft under high sea states can be described more accurately. This not only improves the accuracy of the model but also enhances its adaptability to complex sea states, providing more reliable theoretical support for the safe take-off and landing of seaplanes under high sea states.

[0066] IV. Real-time Analysis Steps for Takeoff and Landing: Considering the strong nonlinearity of the takeoff and landing process of aircraft in sea state 5, the takeoff and landing dynamics of the aircraft are described by a total kinematic equation consisting of the center of mass dynamics equation, the center of mass kinematic equation, the rotational dynamics equation, and the rotational kinematic equation. Based on the total kinematic equation, the wetted area after the influence of waves is introduced to update the original wetted area in the total kinematic equation that is not affected by waves, thereby obtaining the updated total kinematic equation. Based on the updated total kinematic equation, the flight state parameters are calculated to realize the real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

[0067] Specifically, firstly, based on the total equation of motion consisting of the center-of-mass dynamics equation, the center-of-mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation, the wetted area affected by waves is introduced to update the original wetted area unaffected by waves in the total equation of motion, thus obtaining the updated total equation of motion, namely, the updated center-of-mass dynamics equation, the updated center-of-mass kinematics equation, the updated rotational dynamics equation, and the updated rotational kinematics equation. Among them, 1) the updated center-of-mass dynamics equation is shown in the following equation:

[0068] (9)

[0069] In the above formula, These represent the aircraft's velocity along the longitudinal, lateral, and vertical axes in the body coordinate system (i.e., ...). Components of direction; These represent the aircraft's angular velocities in the longitudinal, lateral, and vertical axes, respectively, within the body coordinate system. Components of direction; ; For the mass of the seaplane; It is the acceleration due to gravity; The net forces acting on the aircraft in the body coordinate system are respectively The directional component. For example, It consists of the following forces:

[0070] (10)

[0071] in, Aerodynamic forces acting on the aircraft directional components, The force of water on the aircraft directional components, The thrust of the engine on the aircraft directional components, The gravity acting on the aircraft The directional component.

[0072] Aerodynamic forces in body coordinate system The components in the three directions are shown in the following formula:

[0073] (11)

[0074] (12)

[0075] (13)

[0076] in, For the density of water, The average water flow velocity at the bottom of the aircraft. For the immersion area, , , respectively along Dimensionless aerodynamic coefficients in direction For the angle of attack, , Elevator deflection angle Aileron deflection, Rudder deflection, express Calculation and related. For the aerodynamic derivative, with For example, for about The derivative of .

[0077] And so on, The net forces acting on the aircraft in the body coordinate system are respectively The directional component.

[0078] 2) The updated kinematic equations of the center of mass are shown below:

[0079] (14)

[0080] in, This is the moment of inertia (constant) of the aircraft. This is the aircraft's inertial product (constant). The resultant torque on the aircraft in the body coordinate system The directional component. For example, It consists of the following forces:

[0081] (15)

[0082] in, The aerodynamic torque on the aircraft directional components, The torque of the water acting on the aircraft directional components, The engine thrust torque on the aircraft directional components, The gravitational torque acting on the aircraft The directional component.

[0083] Aerodynamic torque in the body axis system The components in the three directions are shown in the following formula:

[0084] (16)

[0085] (17)

[0086] (18)

[0087] in, , , respectively along Dimensionless aerodynamic torque coefficient in direction This is the aerodynamic derivative.

[0088] And so on, The resultant torques acting on the aircraft in the body coordinate system are respectively The directional component.

[0089] 3) The updated rotational dynamics equations are shown below:

[0090] (19)

[0091] in, These represent the aircraft's center of mass along the longitudinal, lateral, and vertical axes in the ground coordinate system (i.e., ...). Components of direction; .

[0092] 4) The updated rotational kinematic equations are shown below:

[0093] (20)

[0094] In summary, as Figure 6 and 7 As shown, the impact of sea state 5 on the takeoff process of seaplanes can be seen, such as... Figure 8 and 9 As shown, the landing results of the seaplane under sea state 5 can be seen. The rise and fall of the aircraft with the wave force can be clearly and accurately observed, which shows the rationality of this method.

[0095] This invention also relates to a dynamic calculation system for the takeoff and landing process of seaplanes adapted to high sea states. This system corresponds to the aforementioned dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states, and can be understood as a system that implements the aforementioned method. The system includes a data acquisition module, an altitude and attitude correction module, a wetted area calculation module, and a real-time analysis module for the takeoff and landing process, connected sequentially. Specifically,

[0096] The data acquisition module acquires hydrodynamic test data of the bottom hull of the seaplane in real time. The hydrodynamic test data includes wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull.

[0097] The altitude and attitude correction module establishes a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. It then obtains the coordinates of the aircraft's center of mass in the ground coordinate system. Based on the abscissa of the center of mass coordinates and the wave height at the current moment, it establishes an altitude compensation model and an attitude compensation model, respectively. The vertical distance from the current step point to the horizontal plane is input into the altitude compensation model to obtain the vertical distance after wave correction. The pitch angle of the seaplane at the current moment is input into the attitude compensation model to obtain the pitch angle after wave correction.

[0098] The wetted area calculation module calculates the keelline wetted length of the seaplane based on the corrected pitch angle and the corrected vertical distance; it then calculates the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull lift angle, and pitch angle; it calculates the average fuselage wetted length based on the keelline wetted length and bilge wetted length; it then calculates the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; and it corrects the fuselage wetted aspect ratio using an empirical formula method based on hydrodynamic test data to obtain the corrected wetted aspect ratio. Finally, it calculates the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width.

[0099] The real-time analysis module for takeoff and landing processes introduces the wetted area affected by waves into the total motion equation, which is composed of the center of mass dynamics equation, the center of mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation. This updates the original wetted area unaffected by waves in the total motion equation, thereby obtaining the updated total motion equation. Based on the updated total motion equation, the module calculates the flight state parameters to achieve real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

[0100] Preferably, a body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis. The flight state parameters include the aircraft's linear velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, the aircraft's angular velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, and the aircraft's center of mass position, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the ground coordinate system.

[0101] Preferably, in the real-time analysis module for takeoff and landing, the flight state parameters calculated based on the updated full equation of motion specifically include: calculating the aircraft's center of mass position in the longitudinal, lateral, and vertical axes in the ground coordinate system, and the aircraft's linear velocity and angular velocity, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the body coordinate system based on the updated center of mass dynamics equation, center of mass kinematics equation, rotational dynamics equation, and rotational kinematics equation coupled together.

[0102] Preferably, a real-time feedback control algorithm is used to optimize the flight state parameters to obtain optimized flight state parameters, so as to realize real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states.

[0103] This invention provides an objective and scientific method and system for calculating the dynamics of seaplane takeoff and landing in high sea states. By establishing altitude compensation and attitude compensation models, the corrected vertical distance and pitch angle are obtained, comprehensively considering the influence of waves on the motion and attitude of seaplanes in high sea states, thereby ensuring that the aircraft can maintain a stable flight state on the undulating sea surface in high sea states. Furthermore, by using an improved full equation with higher accuracy and nonlinearity to describe the aircraft dynamics process, the dynamic characteristics under complex sea states are captured more accurately, significantly improving the calculation accuracy and efficiency, and exhibiting remarkable speed, real-time performance, and accuracy.

[0104] It should be noted that the specific embodiments described above enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. Therefore, although the present invention has been described in detail with reference to the accompanying drawings and embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention. In short, all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the present invention patent.

Claims

1. A dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states, characterized in that, Includes the following steps: Data acquisition steps: Real-time acquisition of hydrodynamic test data of the bottom hull of the seaplane, including wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull. Altitude and attitude correction steps: Establish a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. Obtain the coordinates of the aircraft's centroid in the ground coordinate system. Based on the horizontal coordinate in the centroid coordinates and the wave height at the current moment, establish an altitude compensation model and an attitude compensation model respectively. Input the vertical distance from the current step point to the horizontal plane into the altitude compensation model to obtain the vertical distance after wave influence correction. The current pitch angle of the seaplane is then input into the attitude compensation model to obtain the pitch angle after wave correction. Steps for calculating the wetted area: Calculate the keelline wetted length of the seaplane based on the corrected pitch angle and corrected vertical distance; calculate the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull tilt angle, and pitch angle; calculate the average fuselage wetted length based on the keelline and bilgeline wetted lengths; calculate the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; correct the fuselage wetted aspect ratio using an empirical formula based on hydrodynamic test data; and calculate the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width. Real-time analysis steps for takeoff and landing: Based on the total motion equation consisting of the center of mass dynamics equation, the center of mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation, the wetted area after wave influence is introduced to update the original wetted area without wave influence in the total motion equation, thereby obtaining the updated total motion equation. Based on the updated total motion equation, the flight state parameters are calculated to realize real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

2. The dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states according to claim 1, characterized in that, A body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis. The flight state parameters include the aircraft's linear velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, the aircraft's angular velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, and the aircraft's center of mass position, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the ground coordinate system.

3. The dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states according to claim 2, characterized in that, In the real-time analysis step of the takeoff and landing process, the flight state parameters calculated based on the updated full motion equations specifically include: calculating the aircraft's center of mass position in the longitudinal, lateral, and vertical axes in the ground coordinate system, and the aircraft's linear velocity and angular velocity, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the body coordinate system based on the updated center of mass dynamics equation, center of mass kinematics equation, rotational dynamics equation, and rotational kinematics equation coupled together.

4. The dynamic calculation method for the takeoff and landing process of seaplanes adapted to high sea states according to claim 2, characterized in that, The calculated flight state parameters are optimized using a real-time feedback control algorithm to obtain optimized flight state parameters, thereby enabling real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states.

5. A dynamic calculation system for the takeoff and landing process of a seaplane adapted to high sea states, characterized in that, It includes a data acquisition module, a height and attitude correction module, an immersion area calculation module, and a real-time analysis module for the takeoff and landing process, all connected in sequence. The data acquisition module acquires hydrodynamic test data of the bottom hull of the seaplane in real time. The hydrodynamic test data includes wave height, pitch angle, hull tilt angle, vertical distance from the step point of the hull to the horizontal plane, and bilge of the hull. The altitude and attitude correction module establishes a ground coordinate system with any point on the sea surface as the origin, the initial direction of the aircraft's motion as the longitudinal axis, the direction of the aircraft's starboard side parallel to the sea surface as the lateral axis, and the Earth's center as the vertical axis. It also obtains the coordinates of the aircraft's centroid in the ground coordinate system. Based on the horizontal coordinate in the centroid coordinate and the wave height at the current moment, it establishes an altitude compensation model and an attitude compensation model, respectively. The vertical distance from the current step point to the horizontal plane is input into the altitude compensation model to obtain the vertical distance after wave influence correction. The current pitch angle of the seaplane is then input into the attitude compensation model to obtain the pitch angle after wave correction. The wetted area calculation module calculates the keelline wetted length of the seaplane based on the corrected pitch angle and the corrected vertical distance; it then calculates the fuselage bilgeline wetted length based on the keelline wetted length, bilge width, hull lift angle, and pitch angle; it calculates the average fuselage wetted length based on the keelline wetted length and bilge wetted length; it then calculates the fuselage wetted aspect ratio based on the average fuselage wetted length and bilge width; and it corrects the fuselage wetted aspect ratio using an empirical formula method based on hydrodynamic test data to obtain the corrected wetted aspect ratio. Finally, it calculates the wetted area of ​​the seaplane at the current moment after being affected by waves based on the corrected wetted aspect ratio and bilge width. The real-time analysis module for takeoff and landing processes introduces the wetted area affected by waves into the total motion equation, which is composed of the center of mass dynamics equation, the center of mass kinematics equation, the rotational dynamics equation, and the rotational kinematics equation. This updates the original wetted area unaffected by waves in the total motion equation, thereby obtaining the updated total motion equation. Based on the updated total motion equation, the module calculates the flight state parameters to achieve real-time dynamic analysis of the takeoff and landing process of seaplanes in high sea states.

6. The dynamic calculation system for the takeoff and landing process of seaplanes adapted to high sea states according to claim 5, characterized in that, A body coordinate system is established with the aircraft's center of mass as the origin, the direction of the aircraft's nose as the longitudinal axis, the direction of the aircraft's starboard side as the lateral axis, and the direction of the aircraft's bottom as the vertical axis. The flight state parameters include the aircraft's linear velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, the aircraft's angular velocity in the longitudinal, lateral, and vertical axes in the body coordinate system, and the aircraft's center of mass position, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the ground coordinate system.

7. The dynamic calculation system for the takeoff and landing process of seaplanes adapted to high sea states according to claim 6, characterized in that, The real-time analysis module for takeoff and landing processes calculates flight state parameters based on the updated full equation of motion. Specifically, this includes: calculating the aircraft's center of mass position in the longitudinal, lateral, and vertical axes in the ground coordinate system, and the aircraft's linear velocity and angular velocity, roll angle, pitch angle, and yaw angle in the longitudinal, lateral, and vertical axes in the body coordinate system, based on the updated center of mass dynamics equation, center of mass kinematics equation, rotational dynamics equation, and rotational kinematics equation coupled together.

8. The dynamic calculation system for the takeoff and landing process of seaplanes adapted to high sea states according to claim 6, characterized in that, A real-time feedback control algorithm is used to optimize the flight state parameters, thereby obtaining optimized flight state parameters to achieve real-time dynamic analysis of the take-off and landing process of seaplanes in high sea states.

Images