Overwater platform simulation model design method for full-automatic landing

Abstract

The invention belongs to the field of simulation model design, and relates to a full-automatic landing-oriented overwater platform simulation model design method, which comprises the following steps: respectively designing a sea wave dip angle simulation model, an atmospheric disturbance model and a plate motion simulation model to establish an overwater platform motion model, so that overwater platform motion simulation under complex sea conditions can be simulated; and a matched water platform motion model is provided for closed-loop high-precision dynamic simulation of the full-automatic landing aircraft ship. When an overwater platform sails on the sea, due to the effects of complex and changeable surges and sea wind, deck movement, deck wind, a stern flow field and the like of the overwater platform are important factors influencing the full-automatic landing guiding safety and success rate. The full-automatic landing technology is high in complexity, complex in closed-loop crosslinking and high in danger level, and it is necessary to provide an overwater platform motion adaptive model under the complex sea condition for aircraft landing simulation.

Description

Technical Field

[0001] The present application belongs to the field of simulation model design, and in particular relates to a method for designing a simulation model of a water platform for fully automatic landing. Background Art

[0002] Fully automatic landing technology is a key technology that current aircraft must have. Compared with the landing of land aircraft, its control is subject to complex and diverse external interference, and the required control accuracy is much higher. When the landing platform is sailing on the sea, it is subject to unpredictable random influences such as wind and waves, which have an impact on the aircraft's sinking speed, attitude, landing point deviation, escape rate, etc., making the landing mission more complicated and greatly reducing safety.

[0003] In order to improve the safety of fully automatic landing, it is necessary to establish a highly realistic water platform motion model that can support closed-loop landing simulation of aircraft and ships, and to conduct in-depth research on the impact of atmospheric disturbances and deck motion estimation during landing, which is very necessary for the establishment of a fully automatic landing aircraft and ship adaptation system. Summary of the invention

[0004] The purpose of this application is to provide a method for designing a water platform simulation model for fully automatic landing, so as to solve the problem of relatively low safety of existing landing water platforms.

[0005] The technical solution of the present application is: a method for designing a water platform simulation model for fully automatic landing, comprising:

[0006] Perform characteristic statistics on random waves, perform wave description modeling based on the characteristic statistical results to obtain ITTC wave spectrum, perform wave inclination simulation based on the ITTC wave spectrum to obtain the wave inclination of long-peaked random waves, and establish a wave inclination simulation model for a fixed point in space based on the wave inclination of long-peaked random waves;

[0007] Collect the free atmospheric turbulence data and ship wake data at the tail of the existing water platform, split the total disturbance formed by the free atmospheric turbulence data and the ship wake data, and establish the relationship between each disturbance component and the total disturbance to form an atmospheric disturbance model;

[0008] The motion posture data of the existing water platform is obtained to solve the position of each reference point on the deck, and the unstable mother ship coordinate system and the stable mother ship coordinate system are established respectively. Then, the displacement motion equation of the water platform is established according to the conversion relationship between the unstable mother ship coordinate system and the stable mother ship coordinate system, thereby forming a deck motion simulation model;

[0009] The water platform motion model is established through the wave inclination simulation model, atmospheric disturbance model and deck motion simulation model. The ideal landing point is solved according to the water platform motion parameters in the unstable mother ship coordinate system and the water platform motion model.

[0010] Preferably, the ITTC wave spectrum is obtained by calculating the wave spectrum density through the wave energy spectrum, and the calculation formula is:

[0011]

[0012] Where S is the energy spectrum of the waves, indicating the size of the wave capacity; A = 0.78, h 1 / 3 is the trinity average wave height; ω is the angular frequency.

[0013] Preferably, the specific method for simulating the wave inclination angle of ocean waves is as follows: firstly, the ITTC wave spectrum is discretized in the simulation frequency band, and the wave inclination angle of the harmonics and the initial phase angle of each harmonic at each specific frequency are determined according to the discretized wave spectrum, and finally, the wave inclination angle of each harmonic is superimposed to obtain the wave inclination angle of the long-peaked random ocean wave in the simulation environment.

[0014] Preferably, the simulation model of the wave inclination angle α(t) of a certain fixed point in the space is:

[0015]

[0016] Where g is the acceleration due to gravity, S τ is the wave spectrum, ω is the wave frequency, and ε is the initial phase angle.

[0017] Preferably, the total disturbance is divided into a free atmospheric turbulence component, a steady-state component of the ship wake, a periodic component of the ship wake, and a random component of the ship wake. Then, the total disturbance in each direction of the atmospheric disturbance model is:

[0018]

[0019] Where U g , V g , W g are the components of the total disturbance in each direction; U1, V1, W1 are the free atmosphere turbulence components; U2, V2, W2 are the steady-state components of the ship wake; U3, V3, W3 are the periodic components of the ship wake; U4, V4, W4 are the random components of the ship wake.

[0020] Preferably, the motion parameters of the water platform include the center coordinate position, the stern reference point, the stern midpoint reference point, the ideal landing point and the position coordinates of the shipborne guidance sensor deviating from the center point in the stable mother ship coordinate system and the three attitude angles of the water platform.

[0021] The water platform simulation model design method for fully automatic landing in this application provides an adaptive water platform and deck motion model for the fully automatic landing scenario in the fully automatic landing ground comprehensive simulation verification process. The model can simultaneously support manned and unmanned aircraft landing verification, improve the aircraft-ship adaptability of aircraft landing, and improve the verification maturity of key technologies such as deck motion estimation and compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution provided by the present application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present application.

[0023] Figure 1 This is a schematic diagram of the overall process of this application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] A water platform simulation model design method for fully automatic landing is proposed. In view of the usage requirements and risks in complex meteorological environments, in order to improve the reliability, safety and availability of fully automatic landing technology, a water platform motion model that supports the fully automatic landing closed-loop process and adapts to complex sea conditions needs to be established for the comprehensive closed-loop simulation verification of fully automatic landing on the ground, so as to improve the aircraft-ship adaptability of aircraft landing and enhance the verification maturity of key technologies such as deck motion estimation and compensation.

[0026] In order to further analyze the impact of irregular deck motion caused by surge and sea breeze on the aircraft landing process when the water platform is sailing at sea, on the basis of conventional six-degree-of-freedom modeling of the water platform, the simulation modeling of wind, ship wake and deck motion is added to improve the realism of aircraft-ship adaptation in the closed-loop simulation of fully automatic landing, and provide support for the research and verification of key technologies of fully automatic landing such as deck motion prediction and deck motion compensation.

[0027] like Figure 1 As shown, the following steps are included:

[0028] Step S100, perform characteristic statistics on random waves, perform wave description modeling based on the characteristic statistical results to obtain ITTC wave spectrum, perform wave inclination simulation based on the ITTC wave spectrum to obtain long-peaked random wave inclination, and establish a wave inclination simulation model of a fixed point in space based on the long-peaked random wave inclination.

[0029] Since random waves will cause irregular effects on the movement of water platforms, the deck plane will translate, rotate and heave with irregular surges. In order to analyze the impact of random waves on aircraft landing guidance, the characteristics of random waves are statistically analyzed, and the wave spectrum density is calculated using the "wave energy spectrum" to obtain the wave spectrum density formula, also known as the ITTC wave spectrum, which is in the form of:

[0030]

[0031] Where S is the energy spectrum of the waves, indicating the size of the wave capacity; A = 0.78, h 1 / 3 is the trinity average wave height; ω is the angular frequency.

[0032] The random wave simulation method is used to simulate the wave inclination angle. Specifically, the ITTC wave spectrum is first discretized in the simulation frequency band, and the wave inclination angle of the harmonics and the initial phase angle of each harmonic at each specific frequency are determined according to the discretized wave spectrum. Finally, the wave inclination angle of each harmonic is superimposed to obtain the long-peak random wave inclination angle in the simulation environment.

[0033] The simulation model of the wave inclination angle α(t) at a fixed point in space established based on the long-peaked random wave inclination angle is:

[0034]

[0035] Where g is the acceleration due to gravity, S τ is the wave spectrum, ω is the wave frequency, and ε is the initial phase angle.

[0036] For each harmonic initial phase angle ε i , since it is a random variable uniformly distributed between (0,2π), the initial phase angle ε of each harmonic is i It can be generated by a pseudo-random number uniformly distributed in (0, 1).

[0037] Step S200, collecting free atmospheric turbulence data and ship wake data at the tail of the existing water platform, splitting the total disturbance formed by the free atmospheric turbulence data and the ship wake data, and establishing the relationship between each disturbance component and the total disturbance to form an atmospheric disturbance model.

[0038] When the water platform is sailing at high speed, a complex induced wake will be generated at the tail, and the aircraft will inevitably be affected by this airflow during the landing process. The airflow disturbance at the tail of the ship affects the aircraft's sinking speed, attitude, landing point deviation, escape rate, etc. The landing mission may become more complicated due to the existence of the ship wake, and the safety is greatly reduced. In order to study the influence of the ship wake on the landing process, an atmospheric disturbance model is established, and the total disturbance of the atmospheric disturbance in three directions in the inertial coordinate system is divided into the following four components: free atmospheric turbulence component, ship wake steady-state component, ship wake periodic component and ship wake random component.

[0039] Therefore, the total disturbance in all directions of the atmospheric disturbance model is:

[0040]

[0041] Where U g , V g , W g are the directional components of the total disturbance, and the meanings of the other parameters are as follows:

[0042] 1) The free atmosphere turbulence components are U1, V1, and W1;

[0043] 2) The steady-state components of the wake are U2, V2, and W2. When a ship is sailing against the wind, the air flows out from the flat protrusion of the ship, generating a rooster-tail-shaped airflow in the vertical plane. This airflow is called a rooster wake because of its shape, which is very similar to a rooster's tail. It can be regarded as a uniform steady flow caused only by the movement of the water platform.

[0044] 3) The periodic components of the wake are U3, V3, and W3, which are the periodic components of the wake and depend on the pitch frequency / amplitude of the ship, the deck wind, and the distance of the aircraft from the ship;

[0045] 4) The random components of the ship wake are U4, V4, and W4, which belong to the category of random element flow just like the free atmospheric turbulence.

[0046] Step S300, obtain the motion posture data of the existing water platform to solve the position of each reference point on the deck, establish an unstable mother ship coordinate system and a stable mother ship coordinate system respectively, and then establish the displacement motion equation of the water platform according to the conversion relationship between the unstable mother ship coordinate system and the stable mother ship coordinate system, thereby forming a deck motion simulation model.

[0047] In the study of aircraft takeoff and landing, the movement of ships caused by the movement of waves is usually called deck movement. Under the influence of wind, waves and other factors, the water platform will produce six degrees of freedom, including linear motion along three coordinate axes: sway, swing, sinking and floating, and rotational motion around the three coordinate axes: roll, pitch and yaw. According to the movement state of the water platform, the deck motion can be divided into longitudinal motion (sway, sinking, pitch) and lateral motion (sway, roll, yaw). In particular, the change in the height of the ideal landing point increases the difficulty of the aircraft landing, and the deck motion needs to be estimated and compensated.

[0048] The deck motion simulation model solves the position of each reference point on the deck according to the motion posture of the water platform. The displacement motion equation of the water platform is established through the conversion relationship between the unstable mother ship coordinate system and the stable mother ship coordinate system, and the deck motion simulation model is established according to the displacement motion equation of the water platform.

[0049] Deck motion posture data is shown in Table 1:

[0050] Table 1 Deck motion parameters simulation

[0051]

[0052]

[0053] Step S400, a water platform motion model is established through a wave inclination angle simulation model, an atmospheric disturbance model and a deck motion simulation model, and according to the center coordinate position of the water platform in the unstable mother ship coordinate system, the stern reference point, the stern midpoint reference point, the ideal landing point and the position coordinates of the shipborne guidance sensor deviating from the center point in the stable mother ship coordinate system, the three attitude angles of the water platform and other information, the ideal landing point, the measurement position of the shipborne guidance sensor and other parameters are solved in combination with the water platform motion model.

[0054] Through the above design, an adaptive water platform and deck motion model is provided for the fully automatic landing scenario in the fully automatic landing ground comprehensive simulation verification process. This model can simultaneously support the landing verification of manned and unmanned aircraft, improve the aircraft-ship adaptability of aircraft landing, and improve the verification maturity of key technologies such as deck motion estimation and compensation.

[0055] Finally, it should be noted that: the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0056] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a water platform simulation model for fully automatic landing, characterized in that: include: Perform characteristic statistics on random waves, perform wave description modeling based on the characteristic statistical results to obtain ITTC wave spectrum, perform wave inclination simulation based on the ITTC wave spectrum to obtain the wave inclination of long-peaked random waves, and establish a wave inclination simulation model for a fixed point in space based on the wave inclination of long-peaked random waves; Collect the free atmospheric turbulence data and ship wake data at the tail of the existing water platform, split the total disturbance formed by the free atmospheric turbulence data and the ship wake data, and establish the relationship between each disturbance component and the total disturbance to form an atmospheric disturbance model; The motion posture data of the existing water platform is obtained to solve the position of each reference point on the deck, and the unstable mother ship coordinate system and the stable mother ship coordinate system are established respectively. Then, the displacement motion equation of the water platform is established according to the conversion relationship between the unstable mother ship coordinate system and the stable mother ship coordinate system, thereby forming a deck motion simulation model; The water platform motion model is established through the wave inclination simulation model, atmospheric disturbance model and deck motion simulation model. The ideal landing point is solved according to the water platform motion parameters in the unstable mother ship coordinate system and the water platform motion model.

2. The method for designing a water platform simulation model for fully automatic landing according to claim 1, characterized in that: The ITTC wave spectrum is obtained by calculating the wave spectrum density through the wave energy spectrum, and the calculation formula is: In the formula, S is the energy spectrum of the wave, indicating the size of the wave capacity; A = 0.78, h 1 / 3 is the trinity average wave height; ω is the angular frequency.

3. The method for designing a water platform simulation model for fully automatic landing according to claim 1, characterized in that: The specific method for simulating the inclination angle of ocean waves is as follows: first, discretize the ITTC wave spectrum in the simulation frequency band, determine the inclination angle of the harmonics and the initial phase angle of each harmonic at each specific frequency according to the discretized wave spectrum, and finally, superimpose the inclination angle of each harmonic to obtain the inclination angle of long-peaked random ocean waves in the simulation environment.

4. The method for designing a water platform simulation model for fully automatic landing as claimed in claim 3, characterized in that: The simulation model of the wave inclination angle α(t) at a fixed point in the space is: Where g is the acceleration due to gravity, S τ is the wave spectrum, ω is the wave frequency, and ε is the initial phase angle.

5. The method for designing a water platform simulation model for fully automatic landing according to claim 1, characterized in that: The total disturbance is divided into the free atmospheric turbulence component, the steady-state component of the ship wake, the periodic component of the ship wake and the random component of the ship wake. The total disturbance in each direction of the atmospheric disturbance model is: Where U g , V g , W g are the components of the total disturbance in each direction; U1, V1, W1 are the free atmosphere turbulence components; U2, V2, W2 are the steady-state components of the ship wake; U3, V3, W3 are the periodic components of the ship wake; U4, V4, W4 are the random components of the ship wake.

6. The method for designing a water platform simulation model for fully automatic landing according to claim 1, characterized in that: The motion parameters of the water platform include the center coordinate position, the stern reference point, the stern midpoint reference point, the ideal landing point, the position coordinates of the shipborne guidance sensor deviating from the center point in the stable mother ship coordinate system, and the three attitude angles of the water platform.

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