Construction method and system for three-dimensional lift-drag ratio corridor model of gliding aircraft and medium

Abstract

The invention provides a construction method and system for a three-dimensional lift-drag ratio corridor model of a gliding aircraft and a medium, and belongs to the technical field of aircraft dynamics and guidance. According to the method, under the condition that a reference attack angle or a heeling angle does not need to be planned in advance, various constraint conditions of a reentry process are converted into a three-dimensional corridor constraint model by selecting a proper three-dimensional corridor frame variable and combining a quasi-equilibrium gliding condition, so that a key technical support is provided for three-dimensional profile planning considering longitudinal and lateral movement requirements. According to the method, the problem of three-dimensional flight corridor generation of reentry trajectory planning of hypersonic gliding aircrafts, reentry aircrafts, sky-earth round-trip aircrafts and the like can be solved, and comprehensive development of technologies of related advanced aircraft platforms, sensors, communication and the like can be dragged; and a supporting effect is also achieved for the reentry trajectory planning problem of other similar platforms such as hypersonic guided missiles.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft dynamics and guidance, and particularly relates to a method, system and medium for constructing a three-dimensional lift-drag ratio corridor model of a gliding aircraft. Background Art

[0002] Hypersonic gliding aircraft is a new type of aircraft that can rely on aerodynamic force to achieve large-range high-speed maneuvering penetration. Due to its flexible and variable trajectory, it is difficult to predict, so it is becoming a research hotspot in the aerospace field. In order to generate a flexible and variable reentry trajectory and enable the aircraft to accurately and safely reach the established target along the designed trajectory, it is necessary to ensure that the designed reentry trajectory meets the requirements of process constraints such as dynamic pressure, overload and heat flux, control constraints, and initial and terminal state conditions. In order to better achieve flexible and variable trajectories, when planning the trajectory, it is not only necessary to consider the longitudinal motion, but also the influence of the lateral motion should be taken into account. Relatively speaking, the reentry corridor adopted by the successfully verified traditional space shuttle standard profile planning method is only a two-dimensional flight corridor, and it is difficult to directly reflect the influence of the lateral motion on the design of the reentry corridor. In addition, when designing the traditional reentry corridor, it is necessary to pre-plan the reference angle of attack profile in advance, so the boundary of the reentry corridor determined by it will inevitably limit the planning range of the reentry flight profile, and thus the inherent maneuvering potential of the aircraft cannot be fully exerted. Therefore, how to quickly construct a three-dimensional flight corridor that can directly reflect the reentry process constraints and at the same time take into account the longitudinal and lateral motion requirements is of great significance for trajectory planning. Summary of the Invention

[0003] In order to take into account various process constraints, control constraints and longitudinal and lateral motion requirements of the reentry trajectory planning of hypersonic gliding aircraft, the present invention proposes a construction scheme for a three-dimensional lift-drag ratio corridor model of a gliding aircraft.

[0004] The present invention can be widely applied to the reentry trajectory planning, guidance and control, and maneuverability calculation of lift reentry vehicles, hypersonic gliding aircraft, cross-domain variable structure high-speed aircraft and other aircraft, and provides technical support for determining the lift-drag ratio feasible boundary of their trajectory planning, guidance and control methods, etc., and has broad military and civilian application prospects and values.

[0005] The first aspect of the present invention proposes a method for constructing a three-dimensional lift-drag ratio corridor model of a gliding aircraft, and the method includes:

[0006] Step S1: Determine the variables of the three-dimensional flight corridor model by analyzing the mapping relationship between the reentry process constraints and the motion model of the gliding aircraft;

[0007] Step S2: Based on the quasi-equilibrium gliding condition, convert the reentry process constraints into longitudinal sub-corridor model constraints;

[0008] Step S3: Based on the longitudinal and lateral motion coupling relationship, construct longitudinal and lateral sub-corridor models;

[0009] Step S4: Combine the longitudinal and lateral sub-corridor models to construct a three-dimensional flight corridor model;

[0010] Step S5: Establish a constraint mapping relationship between the three-dimensional flight corridor model and the control variables;

[0011] Step S6: Set up a simulation scenario and construct a three-dimensional lift-to-drag ratio corridor model for the gliding aircraft.

[0012] According to the method of the first aspect of the present invention, in step S1:

[0013] The energy per unit mass E of the gliding aircraft is:

[0014] E = V 2 / 2 - μ / r

[0015] where V represents the aircraft speed, μ is the gravitational constant of the earth, and r is the distance from the center of mass of the aircraft to the center of the earth;

[0016] Introduce the three-dimensional profile frame quantities (ζ x , ζ y , E), where:

[0017]

[0018] where ζ x , ζ y , ζ represent the longitudinal lift-to-drag ratio, lateral lift-to-drag ratio, and total lift-to-drag ratio of the aircraft respectively, D and L represent the aerodynamic drag acceleration and lift acceleration respectively, and σ represents the bank angle;

[0019] The expressions for D and L are:

[0020]

[0021] where C D and C L are the aerodynamic drag and lift coefficients of the gliding aircraft respectively, which are determined by the control variables angle of attack α, altitude h, aircraft speed V or Mach number Ma; S ref , M represent the aerodynamic characteristic area and the mass of the aircraft respectively; ρ is the atmospheric density; and:

[0022]

[0023] where ρ0 is the atmospheric density at the earth's sea level, and h s represents the generalized altitude of the atmospheric density.

[0024] According to the method of the first aspect of the present invention, in step S2:

[0025] The constraints on the maximum dynamic pressure, maximum overload, and stagnation heat flux density during the reentry process are as follows:

[0026]

[0027] Among them, are the maximum allowable values of the stagnation heat flux density, dynamic pressure, and overload, respectively; K h is an empirical constant for calculating the heat flux density related to the overall aircraft, and g0 is the gravitational acceleration at the Earth's sea level;

[0028] For the reentry flight segment, the quasi-equilibrium glide condition is satisfied:

[0029]

[0030] Among them, γ is the flight path angle, r is the geocentric distance, L represents the lift acceleration, and σ EQ represents the quasi-equilibrium glide bank angle, and g is the Earth's gravitational acceleration;

[0031] Construct the constraints for the longitudinal sub-corridor model:

[0032]

[0033] Among them, D min and D max represent the minimum and maximum drag accelerations corresponding to the reentry process constraints; ζ xmin and ζ xmax are the minimum and maximum longitudinal lift-to-drag ratios allowed during the reentry process, respectively.

[0034] According to the method of the first aspect of the present invention, in step S3:

[0035] Based on the coupling relationship between longitudinal and lateral motions, given the longitudinal lift-to-drag ratio ζ x , the amplitude of the lateral lift-to-drag ratio ζ y is:

[0036]

[0037] Among them, ζ represents the total lift-to-drag ratio of the aircraft;

[0038] For the boundary values ζ x and ζ xmin of ζ xmax there are:

[0039]

[0040] Among them, ζ ymin and ζ ymax represent the minimum and maximum values of the amplitude of the lateral lift-to-drag ratio, respectively.

[0041] According to the method of the first aspect of the present invention, in step S4:

[0042] According to the constructed longitudinal and lateral sub-corridor models, with ζ x as the horizontal axis change amount, the inner upper boundary of its vertical axis is:

[0043]

[0044] wherein, the inner upper boundary of the vertical axis represents the maximum value ζ of the longitudinal lift-drag ratio ζ when the angle of attack takes the maximum value α max ; x The maximum value ζ xmax The amplitude change range of the lateral lift-drag ratio ζ y generated by the change of;

[0045] The change range of the outer upper boundary is:

[0046] |ζ ymax | ∈ {ζ y (α)} + {ζ ypath}

[0047] wherein, + represents taking the union; {ζ y (α)} represents the longitudinal lift-drag ratio generated by the change of the angle of attack α, and {ζ ypath} represents the longitudinal lift-drag ratio determined by the process constraints.

[0048] According to the method of the first aspect of the present invention, in step S5:

[0049] Given the energy E, by traversing all feasible angles of attack α ∈ [α min , α max , the corresponding three-dimensional flight corridor is determined. The three-dimensional flight corridor is obtained by traversing all angles of attack α ∈ [α min , α max and the amplitude of the bank angle |σ| ∈ [σ min , σ max based on the quasi-equilibrium gliding condition; the amplitude of the bank angle satisfies:

[0050]

[0051] wherein, given E, the value range of |σ| changes with D ∈ [D min , D max .

[0052] According to the method of the first aspect of the present invention, the gliding vehicle is a CAV-H general hypersonic gliding vehicle.

[0053] The second aspect of the present invention proposes a system for constructing a three-dimensional lift-drag ratio corridor model of a gliding vehicle. The system includes a processing unit, and the processing unit is configured to execute:

[0054] By analyzing the mapping relationship between the re - entry process constraints and the motion model of the gliding vehicle, the variables of the three - dimensional flight corridor model are determined;

[0055] Based on the quasi - equilibrium gliding condition, the re - entry process constraints are transformed into the constraints of the longitudinal sub - corridor model;

[0056] Based on the coupling relationship between the longitudinal and lateral motions, the longitudinal and lateral sub - corridor models are constructed;

[0057] Combining the longitudinal and lateral sub - corridor models to construct a three - dimensional flight corridor model;

[0058] Establish the constraint mapping relationship between the three - dimensional flight corridor model and the control variables;

[0059] Set up the simulation scenario and construct the three - dimensional lift - to - drag ratio corridor model of the gliding vehicle.

[0060] The third aspect of the present invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, a method for constructing a three - dimensional lift - to - drag ratio corridor model of a gliding vehicle according to the first aspect of the present disclosure is implemented.

[0061] The fourth aspect of the present invention discloses a computer - readable storage medium. A computer program is stored on the computer - readable storage medium. When the computer program is executed by a processor, a method for constructing a three - dimensional lift - to - drag ratio corridor model of a gliding vehicle according to the first aspect of the present disclosure is implemented.

[0062] In summary, without prior planning of the reference angle of attack or bank angle, the present invention selects appropriate three - dimensional corridor frame variables, and then combines the quasi - equilibrium gliding condition to convert various constraint conditions of the re - entry process into a three - dimensional corridor constraint model, thereby providing key technical support for the three - dimensional profile planning that takes into account the longitudinal and lateral motion requirements. The present invention can solve the problem of generating a three - dimensional flight corridor for the re - entry trajectory planning of hypersonic gliding vehicles, re - entry vehicles, space - to - ground reusable vehicles, etc. It can not only drive the comprehensive development of related advanced aircraft platforms, weapons, sensors, communications and other technologies, but also support the re - entry trajectory planning problems of other similar weapon platforms such as hypersonic missiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0064] Figure 1 It is a flowchart of a method according to an embodiment of the present invention.

[0065] Figure 2 It is a flowchart for constructing a three-dimensional lift-drag ratio corridor model according to an embodiment of the present invention.

[0066] Figure 3 It is a schematic diagram of a complete three-dimensional flight corridor according to an embodiment of the present invention.

[0067] Figure 4 It is the E-ζ according to an embodiment of the present invention x corridor sectional view.

[0068] Figure 5 It is the E-ζ according to an embodiment of the present invention y corridor sectional view.

[0069] Figure 6 It is ζ when the normalized energy e = 0.6 according to an embodiment of the present invention x -ζ y sub-corridor schematic diagram. Specific embodiments

[0070] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0071] First embodiment

[0072] A method for constructing a three-dimensional lift-drag ratio corridor model of a gliding aircraft; the main steps include:

[0073] S1: Determine the variables of the three-dimensional flight corridor model.

[0074] Define the unit mass energy E as:

[0075] E = V 2 / 2 - μ / r (1)

[0076] where V represents the aircraft speed, μ is the gravitational constant of the earth, and r is the distance from the center of mass of the aircraft to the center of the earth. Introduce the three-dimensional profile frame quantities (ζ x , ζ y , E), where:

[0077]

[0078] Where D and L are the aerodynamic drag acceleration and the lift acceleration respectively, and σ represents the bank angle.

[0079] S2: Based on the quasi-equilibrium gliding condition, transform the reentry process constraints into the longitudinal sub-corridor model constraints.

[0080] To judge whether the reentry trajectory of a hypersonic glide vehicle is feasible, generally mainly depends on whether it meets the following constraint conditions. First are the constraints of the maximum dynamic pressure, maximum overload, and stagnation point heat flux density during the reentry process:

[0081]

[0082] Where are the maximum allowable values of the stagnation point heat flux density, dynamic pressure, and overload respectively; K h is an empirical constant for calculating the heat flux density related to the overall vehicle, and g0 is the gravitational acceleration at the Earth's sea level. At the same time, for the reentry flight segment, in order to maintain smooth gliding flight, the quasi-equilibrium gliding condition should also be satisfied, that is:

[0083]

[0084] Among them, V represents the vehicle speed, β is the flight path angle, r is the distance from the center of the Earth, L represents the lift acceleration, σ EQ represents the quasi-equilibrium gliding bank angle, and g is the Earth's gravitational acceleration. When the right side of Equation (16) takes the equal sign, it represents the minimum lift acceleration component required for the vehicle to maintain quasi-equilibrium gliding. Therefore, when the lift acceleration of the vehicle is greater than this minimum value, it can ensure that the vehicle can achieve quasi-equilibrium gliding flight. Strictly speaking, it cannot be called a constraint, but just a sufficient condition to ensure the smooth flight of the vehicle.

[0085] According to the above constraint conditions, by taking the equal sign on the right side of Equation (4) and combining with the definition formula in (2), the longitudinal sub-corridor constraint model can be constructed as:

[0086]

[0087] Among them, D min and D max represent the minimum and maximum drag accelerations corresponding to the reentry process constraints; ζ xmin and ζ xmax are respectively the minimum and maximum longitudinal lift-to-drag ratios allowed by the reentry process constraints.

[0088] S3: Based on the longitudinal and lateral motion coupling relationship, construct the lateral sub-corridor model.

[0089] According to the longitudinal and lateral motion coupling relationship, when the longitudinal lift-to-drag ratio ζ x is given, the lateral lift-to-drag ratio ζ yThe size is:

[0090]

[0091] where ζ represents the total lift-drag ratio of the aircraft. Therefore, when determining ζ x the boundary values ζ xmin and ζ xmax are obtained, and then:

[0092]

[0093] where ζ ymin and ζ ymax represent the minimum and maximum values of the lateral lift-drag ratio amplitude respectively. Therefore, Equation (7) is the lateral sub-corridor amplitude model.

[0094] S4: Combine the longitudinal and lateral sub-corridor models to construct a three-dimensional flight corridor model.

[0095] According to the constructed longitudinal and lateral sub-corridor models, with ζ x as the horizontal axis variable, the inner upper boundary of its vertical axis is:

[0096]

[0097] Equation (8) indicates that when the angle of attack takes the maximum value, the maximum value ζ x of the longitudinal lift-drag ratio ζ xmax results in the amplitude change range of the lateral lift-drag ratio ζ y . The change range of the outer upper boundary is jointly determined by two parts, that is:

[0098] |ζ ymax | ∈ {ζ y (α)} + {ζ ypath} (9)

[0099] where the "+" in Equation (28) represents taking the union; {ζ y (α)} represents the longitudinal lift-drag ratio generated by the change of the angle of attack α, and [ζ ypath} represents the longitudinal lift-drag ratio determined by the process constraints. In summary, Equations (8) and (9) together constitute the inner and outer boundaries of the three-dimensional flight corridor model, and the space between them corresponds to the three-dimensional lift-drag ratio corridor.

[0100] S5: Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control quantity.

[0101] According to the above analysis, when the energy E is determined, by traversing all feasible angles of attack α ∈ [α min , α max, by combining equations (8) and (9), the corresponding three-dimensional flight corridor can be obtained. In fact, the three-dimensional flight corridor obtained from equations (8) and (9) is based on the quasi-equilibrium gliding condition, and simultaneously traverses all angles of attack α ∈ [α min , α max and the magnitude of the bank angle |σ| ∈ [σ min , σ max . Because according to the quasi-equilibrium gliding condition (20), the magnitude of the bank angle should satisfy:

[0102]

[0103] Therefore, at a determined E, for each α, the value range of |σ| varies with D ∈ [D min , D max . Obviously, this is only the range of change of the bank angle for the vehicle to maintain a smooth re-entry flight. When the value of the bank angle exceeds this range, it will cause large jitters in the flight and is not conducive to smooth flight.

[0104] It can be seen that for the problem of analytically predicting the re-entry trajectory of a hypersonic glide vehicle, this method is based on constructing a reduced-order lateral energy state model and combines the designed three-dimensional profile to uniquely and analytically obtain the corresponding trajectory terminal landing point. At the same time, in order to improve the trajectory prediction accuracy, through coordinate polar transformation, a piecewise analytical prediction method is proposed, which takes into account both the real-time trajectory prediction requirements and the high-precision requirements, thus providing effective technical support for the ballistic planning and guidance methods of hypersonic glide vehicles.

[0105] Second Embodiment

[0106] As Figure 1-2 shown, this embodiment is a method for constructing a three-dimensional lift-to-drag ratio corridor model of a glide vehicle, including the following steps:

[0107] S1: Deeply analyze the mapping relationship between the constraints and the motion model in the re-entry process of the glide vehicle, and determine the variables of the three-dimensional flight corridor model;

[0108] S2: Based on the quasi-equilibrium gliding condition, transform the re-entry process constraints into longitudinal sub-corridor model constraints;

[0109] S3: Based on the longitudinal-lateral motion coupling relationship, construct longitudinal and lateral sub-corridor models;

[0110] S4: Combine the longitudinal and lateral sub-corridor models to construct a three-dimensional flight corridor model;

[0111] S5: Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control quantity;

[0112] S6: Set up an appropriate simulation scenario, taking the CAV-H general hypersonic glide vehicle as the research object, and simulate and display the effect diagram of the three-dimensional flight corridor model constructed by the method proposed in the present invention.

[0113] In this embodiment, the above implementation process corresponds to Figure 3 the flowchart of the construction of the three-dimensional lift-to-drag ratio corridor model given. In step S1, define the unit mass energy E of the glide vehicle as:

[0114] E = V 2 / 2 - μ / r (11)

[0115] where V represents the vehicle speed, μ is the gravitational constant of the earth, and r is the distance from the vehicle's center of mass to the center of the earth. Introduce the three-dimensional profile frame quantity (ζ x , ζ y , E), where:

[0116]

[0117] In the formula, σ represents the bank angle; D and L are the aerodynamic drag acceleration and lift acceleration respectively, and their definitions are:

[0118]

[0119] In the formula, C D and C L are the aerodynamic drag and lift coefficients of the glide vehicle respectively, which are generally determined by the control variables of the angle of attack α, altitude h, and speed V or Mach number Ma; S ref , M represent the aerodynamic characteristic area and the vehicle mass respectively; ρ is the atmospheric density, and its calculation can be approximately obtained by the following exponential model:

[0120]

[0121] In the formula, ρ0 is the atmospheric density at the earth's sea level, h s represents the generalized altitude of the atmospheric density, and its value can be taken as a constant in simplified calculations.

[0122] In step S2, to judge whether a reentry trajectory of a hypersonic glide vehicle is feasible, generally mainly see whether it meets the following constraint conditions. First is the constraint of the maximum dynamic pressure, maximum overload, and stagnation point heat flux density during the reentry process:

[0123]

[0124] In the formula, are the maximum allowable values of the stagnation point heat flux density, dynamic pressure, and overload respectively; K his the empirical constant for heat flux density calculation related to the overall aircraft, and g0 is the gravitational acceleration at the Earth's sea level. At the same time, for the reentry flight segment, in order to maintain a smooth gliding flight, the quasi-equilibrium gliding condition should also be satisfied, that is:

[0125]

[0126] where V represents the aircraft speed, γ is the flight path angle, r is the distance from the center of the Earth, L represents the lift acceleration, and σ EQ represents the quasi-equilibrium gliding bank angle; g is the gravitational acceleration of the Earth, and its calculation formula is:

[0127]

[0128] When the right side of Equation (16) takes the equal sign, it represents the minimum lift acceleration component required for the aircraft to maintain quasi-equilibrium gliding. Therefore, when the total lift acceleration of the aircraft is greater than this minimum value, it can ensure that the aircraft can achieve quasi-equilibrium gliding flight. Strictly speaking, it cannot be called a constraint, but only a sufficient condition to ensure the smooth flight of the aircraft.

[0129] According to the constraints of the reentry flight process, a mapping relationship model between the drag acceleration and energy can be established:

[0130]

[0131] where D qmax , D nmax , and D eg represent the maximum dynamic pressure, maximum overload, maximum stagnation point heat flux density, and the drag acceleration value corresponding to the quasi-equilibrium gliding condition, respectively. Therefore, after sorting out:

[0132]

[0133] Because the flight path angle γ is almost near 0, combining the quasi-equilibrium gliding condition (16) and taking the equal sign gives:

[0134]

[0135] According to the above constraints, and combining the longitudinal lift-drag ratio ζ in the quasi-equilibrium gliding conditions of Equation (20) and Equation (12) x definition formula, a longitudinal sub-corridor constraint model can be constructed as:

[0136]

[0137] where D min and D max represent the minimum and maximum drag accelerations corresponding to the reentry process constraints; ζ xmin and ζ xmaxThey are the minimum and maximum longitudinal lift-drag ratios allowed by the reentry process constraints respectively.

[0138] In step S3, according to the longitudinal and lateral motion coupling relationship, when a given longitudinal lift-drag ratio ζ x is given, the amplitude of the lateral lift-drag ratio ζ y can be obtained as:

[0139]

[0140] Denote:

[0141]

[0142] For each α, ζ x has a maximum value ζ xmax and ζ xmin . Obviously, when α is determined, they are respectively:

[0143]

[0144] Equation (24) is the boundary of the longitudinal lift-drag ratio corridor under the given energy E. Taking energy E as the independent variable, traversing E ∈ [E0, E f , and then successively solving equation (24), the longitudinal sub-corridor model can be constructed. Similarly, if we let:

[0145]

[0146] Therefore, for each α, the amplitude of ζ y , |ζ y (α)|, has a maximum value |ζ ymax | and |ζ ymin |, that is:

[0147]

[0148] Similarly, taking energy E as the independent variable, traversing E ∈ [E0, E f , combining equation (24), and then successively solving equation (26), the lateral sub-corridor model can be constructed.

[0149] In step S4, for the given three-dimensional profile corridor frame and the given energy E, taking ζ x as the horizontal axis change amount, the inner upper boundary of its vertical axis is:

[0150]

[0151] While the outer upper boundary is jointly determined by two parts, that is:

[0152]

[0153] Among them, the "+" in formula (28) represents taking the union. Therefore, when the energy E is determined, by traversing all feasible angles of attack α ∈ [α min , α max , combining formulas (27) and (28), the corresponding three-dimensional flight corridor can be obtained. To obtain the three-dimensional flight corridor model for the entire reentry flight process, it can be divided into two steps:

[0154] The first step: First, take the energy E as the independent variable, and then by traversing all feasible angles of attack α ∈ [α min , α max , combining formulas (27) and (28), the corresponding three-dimensional flight corridor can be obtained;

[0155] The second step: Then traverse E ∈ [E0, E f , and repeat Step1, so that the entire reentry three-dimensional flight corridor model can be obtained.

[0156] In step S5, in fact, the three-dimensional flight corridor obtained from formulas (27) and (28) is based on the quasi-equilibrium gliding condition, while traversing all angles of attack α ∈ [α min , α max and the magnitude of the bank angle |σ| ∈ [σ min , σ max . Because according to the quasi-equilibrium gliding condition (20), the magnitude of the bank angle should satisfy:

[0157]

[0158] Therefore, at the determined E, for each α, the value range of |σ| changes with D ∈ [D min , D max . To obtain the mapping relationship between the bank angle and the three-dimensional flight corridor model for the entire reentry process, it is also necessary to traverse E ∈ [E0, E f , and then repeat to solve the value range of |σ| determined by formula (29) at each corresponding E. Obviously, this is only the change range of the bank angle for the aircraft to maintain stable reentry flight. When the value of the bank angle exceeds this range, it will cause large jitters in flight and is not conducive to stable flight.

[0159] In step S6, in order to verify the feasibility of constructing the above three-dimensional lift-drag ratio corridor model, CAV-H is used for simulation verification. CAV-H is a general hypersonic vehicle demonstration and verification model produced by Lockheed Martin Corporation in the United States. Its mass is 908 kg, the aerodynamic reference area is 0.908 m2, and the aerodynamic coefficient is represented by a fitting function of the angle of attack and Mach number. Set the initial point altitude to 51 km, the speed to 5600 m / s, the initial speed inclination angle to 0, fly in the due east direction initially, and the initial point longitude and latitude to (0°, 0°). It is required that the terminal altitude of the gliding vehicle is 32 km and the terminal speed is 2700 m / s. In addition, during the reentry flight of the gliding vehicle, the maximum overload should not exceed 3g, the maximum dynamic pressure should not exceed 80 kPa, and the stagnation point heat flux density constraint is 2200 KW / m2. At the same time, limit the value ranges of the angle of attack and bank angle during the reentry process of the vehicle, that is, α ∈ [10°, 20°], σ ∈ [-85°, 85°]. According to the above simulation scenario and combining with the previous algorithm, the simulation verification of the three-dimensional flight corridor model is carried out respectively below.

[0160] The three-dimensional flight corridor results obtained by the simulation are as Figure 3-6 shown. Among them, Figure 3 represents the complete three-dimensional flight corridor, Figure 4 and Figure 5 are successively the display results of the three-dimensional flight corridor from different perspectives, while Figure 6 represents the local sectional view when the normalized energy e = 0.6.

[0161] Analysis shows that Figure 3 the simulation results of the three-dimensional flight corridor in Figure 4 are consistent with the theoretical results of equations (27) and (28), that is, the inner boundary of the corridor is jointly produced by the lift-drag ratio corresponding to the maximum angle of attack and the feasible change range of the longitudinal lift-drag ratio under the process constraints. The outer boundary is divided into two parts. One part is jointly produced by the lift-drag ratio corresponding to the minimum angle of attack and the feasible change range of the longitudinal lift-drag ratio corresponding to the quasi-equilibrium gliding condition, that is, the outer boundary of the minimum angle of attack corridor; the other part is jointly produced by the lift-drag ratio corresponding to the change from the minimum angle of attack to the maximum angle of attack and the feasible change range of the longitudinal lift-drag ratio, that is, the outer boundary of the reentry process constraint. In fact, for Figure 4 the upper boundary of the corridor, it can actually be understood as the upper boundary determined by the quasi-equilibrium gliding condition, and its lower boundary corresponds to the reentry process constraint. When the longitudinal lift-drag ratio is lower than the lower boundary value of the corridor, due to the limited longitudinal available lift of the vehicle, to further reduce the lift-drag ratio, only the drag acceleration can be increased, which will lead to the process constraints such as the maximum overload and dynamic pressure exceeding the boundary values. Figure 5 The upper and lower boundaries of the corridor in Figure 6It gives the corridor of the available lateral lift-drag ratio varying with the longitudinal lift-drag ratio when the normalized energy e = 0.6. Therefore, to make the designed three-dimensional profile feasible, it is necessary to ensure that it is within the corridor constraint range, especially the upper outer boundary of the corridor constrained during the reentry process. Once exceeded, the reentry process constraints will not be satisfied, resulting in mission failure.

[0162] Based on the above analysis, the essence of three-dimensional profile design is the process of allocating the longitudinal and lateral lift-drag ratios. The total lift-drag ratio is fixed. If more is allocated longitudinally, the amount available for lateral motion adjustment will decrease; vice versa. Compared with the traditional two-dimensional profile, the three-dimensional profile intuitively and clearly shows the process of on-demand allocation of the aircraft's maneuverability.

[0163] It can be seen that the above method aims at the problem of reentry trajectory analytical prediction of hypersonic glide vehicles. Based on the construction of a reduced-order lateral energy state model and combined with the designed three-dimensional profile, the corresponding trajectory terminal landing point is uniquely obtained analytically. At the same time, to improve the trajectory prediction accuracy, a piecewise analytical prediction method is proposed through coordinate polar transformation, which takes into account both the real-time trajectory prediction requirements and the high-precision requirements, thus providing effective technical support for the ballistic planning and guidance methods of hypersonic glide vehicles.

[0164] The method of the present invention is based on the quasi-equilibrium glide condition. By reasonably selecting the three-dimensional profile frame variables, a method for constructing a three-dimensional lift-drag ratio corridor model of a glide vehicle that comprehensively considers various process constraints, control constraints, and longitudinal and lateral motion requirements is constructed. Since it does not need to rely on a pre-planned reference angle of attack or bank angle scheme and takes into account the longitudinal and lateral motion requirements, the obtained three-dimensional flight corridor can better reflect the inherent maneuverability boundary of the glide vehicle. Furthermore, when using this flight corridor model for trajectory planning, it can be ensured that the obtained trajectory can not only better exert the lateral large-maneuver flight potential of the glide vehicle but also ensure that it meets various reentry process constraints and the trajectory is feasible. Therefore, using the method proposed by the present invention can solve the problem of generating the three-dimensional flight corridor for reentry trajectory planning of hypersonic glide vehicles, reentry vehicles, space-to-ground reusable vehicles, etc. It can not only drive the comprehensive development of related advanced aircraft platforms, weapons, sensors, communications and other technologies but also support the reentry trajectory planning problems of other similar weapon platforms such as hypersonic missiles.

[0165] Please note that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as falling within the scope described in this specification. The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for constructing a three-dimensional lift-to-drag ratio corridor model of a gliding aircraft, characterized in that, The method includes: Step S1: Determine the variables of the three-dimensional flight corridor model by analyzing the mapping relationship between the re-entry process constraints and the motion model of the gliding vehicle. Step S2: Based on the quasi-equilibrium gliding condition, transform the re-entry process constraints into the constraints of the longitudinal sub-corridor model. Step S3: Based on the coupling relationship between the longitudinal and lateral motions, construct the longitudinal and lateral sub-corridor models. Step S4: Combine the longitudinal and lateral sub-corridor models to construct the three-dimensional flight corridor model. Step S5: Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control quantity. Step S6: Set up the simulation scenario and construct the three-dimensional lift-to-drag ratio corridor model of the gliding vehicle.

2. The construction method of a three-dimensional lift-to-drag ratio corridor model of a gliding aircraft according to claim 1, characterized in that In Step S1: The specific mechanical energy E per unit mass of the gliding vehicle is: E = V 2 / 2 - μ / r where V represents the vehicle speed, μ is the gravitational constant of the earth, and r is the distance from the vehicle's center of mass to the center of the earth. Introduce the three-dimensional sectional frame quantities ($\zeta$ x , $\zeta$ y , E), where: Among them, ζ x , ζ y , ζ respectively represent the longitudinal lift-drag ratio, the lateral lift-drag ratio, and the total lift-drag ratio of the aircraft. D and L respectively represent the aerodynamic drag acceleration and the lift acceleration, and σ represents the bank angle; The expressions of D and L are: Among them, C D and C L are respectively the aerodynamic drag and lift coefficient of the gliding aircraft, which are determined by the control variables of the angle of attack α, altitude h, aircraft speed V or Mach number Ma; S ref , M respectively represent the aerodynamic characteristic area and the aircraft mass; ρ is the atmospheric density; and: where ρ0 is the atmospheric density at the Earth's sea level, and h s represents the generalized altitude of the atmospheric density.

3. The method for constructing a three-dimensional lift-to-drag ratio corridor model of a gliding aircraft according to claim 2, characterized in that, In Step S2: The constraints of the maximum dynamic pressure, maximum overload, and stagnation point heat flux density during the re-entry process are: Among them, are the maximum allowable values of the stagnation heat flux density, dynamic pressure, and overload, respectively; K h is an empirical constant for calculating the heat flux density related to the overall aircraft, and g0 is the gravitational acceleration at the Earth's sea level; For the re-entry flight segment, the quasi-equilibrium gliding condition is satisfied: where γ is the flight path angle, r is the geocentric distance, L represents the lift acceleration, and σ EQ represents the quasi-equilibrium glide bank angle, and g is the acceleration due to gravity of the Earth; Construct the constraints of the longitudinal sub-corridor model: Among them, D min and D max represent the minimum and maximum drag acceleration corresponding to the reentry process constraints; ζ xmin and ζ xmax are respectively the minimum and maximum longitudinal lift-drag ratios allowed by the reentry process constraints.

4. The construction method of a three-dimensional lift-drag ratio corridor model of a gliding aircraft according to claim 1, characterized in that, In Step S3: Based on the coupling relationship between longitudinal and lateral motions, given the longitudinal lift-drag ratio ζ x , the amplitude of the lateral lift-drag ratio ζ y is as follows: where ζ represents the total lift-to-drag ratio of the vehicle. For ζ x the boundary values of ζ xmin and ζ xmax there are: where ζ ymin and ζ ymax represent the minimum and maximum values of the magnitude of the lateral lift-drag ratio, respectively.

5. The construction method of a three-dimensional lift-to-drag ratio corridor model of a gliding aircraft according to claim 4, characterized in that In Step S4: According to the constructed longitudinal and lateral sub-corridor models, with ζ x as the horizontal axis change amount, the inner upper boundary of its vertical axis is: Among them, the upper boundary on the inner side of the vertical axis represents the maximum value ζ of the longitudinal lift-drag ratio ζ when the angle of attack takes the maximum value α max ; x The maximum value ζ xmax of the lateral lift-drag ratio ζ generated by the change y within the amplitude change range; The variation range of the outer upper boundary is: |ζ ymax | ∈ {ζ y (α)} + {ζy path} Among them, + represents taking the union; {ζ y (α)} represents the longitudinal lift-drag ratio generated by the change in the angle of attack α, {ζ ypath} represents the longitudinal lift-drag ratio determined by the process constraints.

6. The construction method of a three-dimensional lift-drag ratio corridor model of a gliding aircraft according to claim 5, characterized in that, In Step S5: Given an energy E, by traversing all feasible angles of attack α ∈ [α min , α max , the corresponding three-dimensional flight corridor is determined. The three-dimensional flight corridor is obtained by traversing all angles of attack α ∈ [α min , α max and the magnitude of the bank angle |σ| ∈ [σ min , σ max based on the quasi-equilibrium gliding condition; the magnitude of the bank angle satisfies: Among them, given E, the value range of |σ| changes with D ∈ [D min , D max .

7. The construction method of a three-dimensional lift-to-drag ratio corridor model of a gliding aircraft according to claim 6, characterized in that, In the method, the gliding vehicle is a CAV-H general hypersonic gliding vehicle.

8. A system for constructing a three-dimensional lift-to-drag ratio corridor model of a gliding vehicle, characterized in that, The system includes a processing unit configured to execute: Determine the variables of the three-dimensional flight corridor model by analyzing the mapping relationship between the re-entry process constraints and the motion model of the gliding vehicle. Based on the quasi-equilibrium gliding condition, transform the re-entry process constraints into the constraints of the longitudinal sub-corridor model. Based on the coupling relationship between the longitudinal and lateral motions, construct the longitudinal and lateral sub-corridor models. Combine the longitudinal and lateral sub-corridor models to construct the three-dimensional flight corridor model. Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control quantity. Set up the simulation scenario and construct the three-dimensional lift-to-drag ratio corridor model of the gliding vehicle.

9. An electronic device, characterized in that, The electronic device includes a memory and a processor. When the processor executes the computer program stored in the memory, it implements the method for constructing a three-dimensional lift-to-drag ratio corridor model of a gliding vehicle according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program. When the computer program is executed by the processor, it implements the method for constructing a three-dimensional lift-to-drag ratio corridor model of a gliding vehicle according to any one of claims 1-7.

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