A method, system, and medium for constructing a three-dimensional lift-to-drag ratio corridor model for a glider.

Abstract

This invention proposes a method, system, and medium for constructing a three-dimensional lift-to-drag ratio corridor model for gliders, belonging to the field of aircraft dynamics and guidance technology. Without prior planning of reference angle of attack or roll angle, this invention transforms various constraints of the reentry process into a three-dimensional corridor constraint model by selecting appropriate three-dimensional corridor frame variables and combining them with quasi-equilibrium gliding conditions. This provides key technical support for three-dimensional profile planning that considers both longitudinal and lateral motion requirements. This invention can solve the problem of generating three-dimensional flight corridors for reentry trajectory planning of hypersonic gliders, reentry vehicles, and space-to-ground vehicles. It will not only drive the comprehensive development of related advanced aircraft platforms, sensors, and communication technologies, but also support the reentry trajectory planning problems of other similar platforms such as hypersonic missiles.

Description

Technical Field

[0001] This invention belongs to the field of aircraft dynamics and guidance technology, and particularly relates to a method, system and medium for constructing a three-dimensional lift-to-drag ratio corridor model for a glider. Background Technology

[0002] Hypersonic glide vehicles are a new type of aircraft capable of high-speed, wide-range maneuvering penetration using aerodynamics. Due to their highly variable and unpredictable trajectories, they are becoming a hot research topic in the aerospace field. To generate flexible reentry trajectories that allow the vehicle to accurately and safely reach its target, it is essential to ensure that the designed reentry trajectory meets process constraints such as dynamic pressure, overload, and thermal flux, as well as control constraints and initial and terminal state conditions. To better achieve flexible trajectories, trajectory planning must consider not only longitudinal motion but also lateral motion. In contrast, the traditional Space Shuttle standard profile planning method, which has been successfully validated, uses only a two-dimensional flight corridor, and the influence of lateral motion is difficult to directly reflect in the reentry corridor design. Furthermore, traditional reentry corridor design requires prior planning of a reference angle-of-attack profile, which inevitably limits the planning range of the reentry flight profile, thus failing to fully utilize the vehicle's inherent maneuverability potential. Therefore, how to quickly construct a three-dimensional flight corridor that can directly reflect the reentry process constraints while also taking into account the longitudinal and lateral motion requirements is of great significance for trajectory planning. Summary of the Invention

[0003] In order to comprehensively consider the various process constraints, control constraints, and longitudinal and lateral motion requirements of hypersonic glider reentry trajectory planning, this invention proposes a construction scheme for a three-dimensional lift-to-drag ratio corridor model of gliders.

[0004] This invention can be widely applied to the reentry trajectory planning, guidance and control, and maneuverability calculation of aircraft such as lift-type reentry vehicles, hypersonic gliders, and trans-domain variable-structure high-speed vehicles. It provides technical support for determining the feasible boundary of lift-to-drag ratio in trajectory planning, guidance and control methods, and has broad military and civilian application prospects and value.

[0005] The first aspect of this invention proposes a method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider, the method comprising:

[0006] Step S1: By analyzing the mapping relationship between the reentry process constraints and the motion model of the glider, determine the variables of the three-dimensional flight corridor model;

[0007] Step S2: Based on the quasi-equilibrium gliding condition, the reentry process constraints are transformed 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: Construct a three-dimensional flight corridor model by combining the longitudinal and lateral sub-corridor models;

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

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

[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 glider is:

[0014] E = V 2 / 2-μ / r

[0015] Where V represents the velocity of the spacecraft, μ is the Earth's gravitational constant, and r is the distance from the center of mass of the spacecraft to the center of the Earth;

[0016] Introducing three-dimensional profile frame quantity (ζ) x ,ζ y ,E), where:

[0017]

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

[0019] The expressions for D and L are:

[0020]

[0021] Among them, C D and C L These are the aerodynamic drag and lift coefficients of the glider, determined by the control variables angle of attack α, altitude h, and vehicle speed V or Mach number Ma; S ref M and 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 sea level, h s This indicates the generalized height of atmospheric density.

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

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

[0026]

[0027] in, These are the maximum permissible values ​​for stagnation heat flux density, dynamic pressure, and overload, respectively; K h The empirical constant for calculating the heat flux density related to the overall spacecraft is g0, where g0 is the gravitational acceleration at sea level.

[0028] For the reentry phase, the quasi-equilibrium gliding conditions are met:

[0029]

[0030] Where γ is the flight path angle, r is the distance from the Earth's center, L represents the lift acceleration, and σ EQ This represents the quasi-equilibrium gliding tilt angle, where g is the Earth's gravitational acceleration;

[0031] Constructing constraints for the vertical sub-corridor model:

[0032]

[0033] Among them, D min and D max ζ represents the minimum and maximum drag accelerations corresponding to the reentry process constraints; xmin and ζ xmax These are the minimum and maximum longitudinal lift-to-drag ratios allowed by the reentry process constraints, 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 motion, given the longitudinal lift-to-drag ratio ζ x Lateral lift-to-drag ratio ζ y The amplitude is:

[0036]

[0037] Where ζ represents the overall lift-to-drag ratio of the aircraft;

[0038] For ζ x boundary value ζ xmin and ζ xmax Then we have:

[0039]

[0040] Where, ζ ymin and ζ ymax These represent the minimum and maximum values ​​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] Based on the constructed longitudinal and lateral sub-corridor models, with ζ x As a variable on the horizontal axis, its upper inner boundary on the vertical axis is:

[0043]

[0044] Among them, the upper boundary inside the vertical axis represents the angle of attack, which takes the maximum value α. max Longitudinal lift-to-drag ratio ζ x The maximum value ζ xmax The change in lateral lift-to-drag ratio ζ y The range of amplitude variation;

[0045] The range of variation of the outer upper boundary is as follows:

[0046] |ζ ymax |∈{ζ y (α)}+{ζ ypath}

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

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

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

[0050]

[0051] Wherein, given E, the range of values ​​for |σ| varies with D∈[D min D max ]change.

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

[0053] A second aspect of the present invention provides a system for constructing a three-dimensional lift-to-drag ratio corridor model of a glider, the system comprising a processing unit configured to perform:

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

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

[0056] Based on the coupling relationship between longitudinal and lateral motion, construct longitudinal and lateral sub-corridor models;

[0057] A three-dimensional flight corridor model is constructed by combining longitudinal and lateral sub-corridor models;

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

[0059] Set up a simulation scenario and construct a three-dimensional lift-to-drag ratio corridor model for the glider.

[0060] A third aspect of this invention discloses an electronic device. The electronic device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider according to the first aspect of this disclosure.

[0061] A fourth aspect of this invention discloses a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements a method for constructing a three-dimensional lift-to-drag ratio corridor model for a glider according to the first aspect of this disclosure.

[0062] In summary, this invention, without requiring prior planning of reference angle of attack or roll angle, transforms various constraints of the reentry process into a three-dimensional corridor constraint model by selecting appropriate three-dimensional corridor frame variables and combining them with quasi-equilibrium gliding conditions. This provides key technical support for three-dimensional profile planning that considers both longitudinal and lateral motion requirements. This invention can solve the problem of generating three-dimensional flight corridors for reentry trajectory planning of hypersonic gliders, reentry vehicles, and space-to-ground vehicles. It will not only drive the comprehensive development of related advanced aircraft platforms, weapons, sensors, and communication technologies, but will also support the reentry trajectory planning problems of other similar weapon platforms such as hypersonic missiles. Attached Figure Description

[0063] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

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

[0065] Figure 2 A flowchart illustrating the construction of a three-dimensional lift-to-drag ratio corridor model according to an embodiment of the present invention.

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

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

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

[0069] Figure 6 ζ is the normalized energy e = 0.6 according to an embodiment of the present invention. x -ζ y Schematic diagram of the sub-corridor. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0071] First Embodiment

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

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

[0074] Define the energy per unit mass, E, as:

[0075] E = V 2 / 2-μ / r (1)

[0076] Where V represents the spacecraft velocity, μ is the Earth's gravitational constant, and r is the distance from the spacecraft's center of mass to the Earth's center. A three-dimensional profile frame quantity (ζ) is introduced. x ,ζ y ,E), where:

[0077]

[0078] In the formula, D and L are the aerodynamic drag acceleration and lift acceleration, respectively, and σ represents the tilt angle.

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

[0080] To determine the feasibility of a hypersonic glide vehicle's reentry trajectory, the following constraints are generally considered: First, the constraints on maximum dynamic pressure, maximum overload, and stagnation point heat flux density during reentry.

[0081]

[0082] In the formula, These are the maximum permissible values ​​for stagnation heat flux density, dynamic pressure, and overload, respectively; K h The empirical constant for calculating the heat flux density related to the overall spacecraft is given, where g0 is the gravitational acceleration at sea level. Additionally, for the reentry phase, to maintain stable gliding flight, the quasi-equilibrium gliding condition must be satisfied, namely:

[0083]

[0084] Where V represents the aircraft velocity, β is the flight path angle, r is the distance from the Earth's center, L represents the lift acceleration, and σ EQ This represents the quasi-equilibrium gliding tilt angle, where g is the Earth's gravitational acceleration. When the right-hand 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 aircraft's lift acceleration 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 rather a sufficient condition to ensure stable flight of the aircraft.

[0085] Based on the above constraints, by taking the equality sign on the right side of equation (4) and combining it with the definition in (2), the longitudinal sub-corridor constraint model can be constructed as follows:

[0086]

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

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

[0089] Based on the longitudinal and lateral motion coupling relationship, when the longitudinal lift-to-drag ratio ζ is given x At that time, the lateral lift-to-drag ratio ζ can be obtained. yThe size is:

[0090]

[0091] Where ζ represents the overall lift-to-drag ratio of the aircraft. Therefore, when ζ is determined... x boundary value ζ xmin and ζ xmax Then, we can obtain:

[0092]

[0093] Where, ζ ymin and ζ ymax These represent the minimum and maximum values ​​of the lateral lift-to-drag ratio, 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] Based on the constructed longitudinal and lateral sub-corridor model, with ζ x As a variable on the horizontal axis, its upper inner boundary on the vertical axis is:

[0096]

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

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

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

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

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

[0102]

[0103] Therefore, at a given point E, for each α, the range of values ​​for |σ| varies with D∈[D]. min D max The change is obvious. This only refers to the range of roll angle changes for the aircraft to maintain stable reentry flight. When the roll angle exceeds this range, it will cause significant shaking during flight, which is detrimental to stable flight.

[0104] As can be seen, this method addresses the analytical prediction problem of reentry trajectories for hypersonic glide vehicles. Based on a reduced-order lateral energy state model and combined with a designed three-dimensional profile, it uniquely and analytically obtains the corresponding trajectory terminal landing point. Furthermore, to improve trajectory prediction accuracy, a piecewise analytical prediction method is proposed through coordinate polar transformation. This method ensures that real-time trajectory prediction requirements are met while also considering high accuracy, thus providing effective technical support for hypersonic glide vehicle trajectory planning and guidance methods.

[0105] Second Embodiment

[0106] like Figures 1-2 As shown in the figure, this embodiment is a method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider, including the following steps:

[0107] S1: Conduct in-depth analysis of the mapping relationship between constraints and motion model of glider reentry process, and determine the variables of the three-dimensional flight corridor model;

[0108] S2: Based on the quasi-equilibrium gliding condition, the reentry process constraints are transformed into longitudinal sub-corridor model constraints;

[0109] S3: Based on the longitudinal and 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 variables;

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

[0113] In this embodiment, the above implementation process corresponds to Figure 3 The given flowchart describes the construction of a three-dimensional lift-to-drag ratio corridor model. In step S1, the energy per unit mass E of the glider is defined as:

[0114] E = V 2 / 2-μ / r (11)

[0115] Where V represents the spacecraft velocity, μ is the Earth's gravitational constant, and r is the distance from the spacecraft's center of mass to the Earth's center. A three-dimensional profile frame quantity (ζ) is introduced. x ,ζ y ,E), where:

[0116]

[0117] In the formula, σ represents the tilt angle; D and L are the aerodynamic drag acceleration and lift acceleration, respectively, and are defined as follows:

[0118]

[0119] In the formula, C D and C L These are the aerodynamic drag and lift coefficients of a glider, respectively, and are generally determined by the control parameters angle of attack α, altitude h, and velocity V or Mach number Ma; S ref M and M represent the aerodynamic characteristic area and the mass of the aircraft, respectively; ρ is the atmospheric density, which can be approximated by the following exponential model:

[0120]

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

[0122] In step S2, the feasibility of a hypersonic glide vehicle's reentry trajectory is evaluated, generally by checking whether it meets the following constraints. First, there are constraints on the maximum dynamic pressure, maximum overload, and stagnation point heat flux density during the reentry process:

[0123]

[0124] In the formula, These are the maximum permissible values ​​for stagnation heat flux density, dynamic pressure, and overload, respectively; K hThe empirical constant for calculating the heat flux density related to the overall spacecraft is given, where g0 is the gravitational acceleration at sea level. Additionally, for the reentry phase, to maintain stable gliding flight, the quasi-equilibrium gliding condition must be satisfied, namely:

[0125]

[0126] Where V represents the aircraft velocity, γ is the flight path angle, r is the distance from the Earth's center, L represents the lift acceleration, and σ EQ This represents the quasi-equilibrium gliding tilt angle; g is the Earth's gravitational acceleration, calculated as follows:

[0127]

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

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

[0130]

[0131] Among them, D qmax D nmax , and D eg Let represent the maximum dynamic pressure, maximum overload, maximum stagnation point heat flux density, and drag acceleration values ​​corresponding to the quasi-equilibrium gliding conditions, respectively. Therefore, we can summarize as follows:

[0132]

[0133] Since the flight path angle γ is almost 0, combining the quasi-equilibrium gliding condition (16) and taking the equality, we get:

[0134]

[0135] Based on the above constraints, and combined with the longitudinal lift-to-drag ratio ζ in the quasi-equilibrium gliding conditions (20) and (12), x The defined formula allows for the construction of a longitudinal sub-corridor constraint model as follows:

[0136]

[0137] Among them, D min and D max ζ represents the minimum and maximum drag accelerations corresponding to the reentry process constraints; xmin and ζ xmaxThese represent the minimum and maximum longitudinal lift-to-drag ratios allowed by the reentry process constraints, respectively.

[0138] In step S3, based on the longitudinal and lateral motion coupling relationship, when a given longitudinal lift-to-drag ratio ζ is obtained... x At that time, the lateral lift-to-drag ratio ζ can be obtained. y The amplitude is:

[0139]

[0140] remember:

[0141]

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

[0143]

[0144] Equation (24) represents the longitudinal lift-to-drag ratio corridor boundary given energy E. Using energy E as the independent variable, the equation iterates through E∈[E0, E... f Then, we can sequentially calculate equation (24) to construct the vertical sub-corridor model. Similarly, if we let:

[0145]

[0146] Therefore, for every α, ζ y Amplitude | ζ y (α)|all have a maximum value|ζ ymax | and |ζ ymin |, that is:

[0147]

[0148] Similarly, with energy E as the independent variable, we iterate through E∈[E0,E... f Combine equation (24) and then successively solve equation (26) to construct the lateral sub-corridor model.

[0149] In step S4, for a given three-dimensional profile corridor frame, for a given energy E, with ζ x As a variable on the horizontal axis, its upper inner boundary on the vertical axis is:

[0150]

[0151] The outer upper boundary is determined by two parts:

[0152]

[0153] In equation (28), the "+" sign indicates taking the union. Therefore, when the energy E is determined, by traversing all feasible angles of attack α∈[α... min ,α max By combining equations (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, two steps can be taken:

[0154] Step 1: First, take energy E as the independent variable, and then iterate through all feasible angles of attack α∈[α... min ,α max By combining equations (27) and (28), the corresponding three-dimensional flight corridor can be obtained;

[0155] Step 2: Then iterate through E∈[E0,E... f Repeat Step 1 to obtain the entire reentry 3D flight corridor model.

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

[0157]

[0158] Therefore, at a given point E, for each α, the range of values ​​for |σ| varies with D∈[D]. min D max [Changes]. To obtain the mapping relationship between the roll angle of the entire reentry process and the three-dimensional flight corridor model, it is necessary to traverse E∈[E0,E...] again. f Then, the range of |σ| values ​​determined by equation (29) is repeatedly solved for each E. Obviously, this is only the range of the tilt angle variation for the aircraft to maintain stable reentry flight. When the tilt angle exceeds this range, it will cause large vibrations in the flight, which is not conducive to stable flight.

[0159] In step S6, to verify the feasibility of constructing the three-dimensional lift-to-drag ratio corridor model, CAV-H was used for simulation verification. CAV-H is a general-purpose hypersonic vehicle demonstration model manufactured by Lockheed Martin, with a mass of 908 kg, an aerodynamic reference area of ​​0.908 m², and aerodynamic coefficients represented by a fitting function of angle of attack and Mach number. The initial altitude was set to 51 km, the speed to 5600 m / s, the initial velocity tilt angle to 0°, and the initial orientation to fly due east, with the initial latitude and longitude at (0°, 0°). The terminal altitude of the glider was required to be 32 km, and the terminal speed to be 2700 m / s. Furthermore, during reentry, the glider should meet the following requirements: maximum overload not exceeding 3g, maximum easterly pressure not exceeding 80 kPa, and stagnation point heat flux density constrained to 2200 KW / m². Simultaneously, the range of angle of attack and tilt angle during reentry was limited, i.e., α ∈ [10°, 20°], σ ∈ [-85°, 85°]. Based on the above simulation scenario and the algorithm described above, the following sections will conduct simulation verification of the construction of a three-dimensional flight corridor model.

[0160] The simulation results of the three-dimensional flight corridor are as follows: Figures 3-6 As shown. Among them, Figure 3 This represents a complete three-dimensional flight corridor. Figure 4 and Figure 5 These are the display results of the 3D flight corridor from different perspectives, and... Figure 6 This represents a local cross-sectional view when the normalized energy e = 0.6.

[0161] Analysis shows that, Figure 3 The simulation results of the three-dimensional flight corridor are consistent with the theoretical results of equations (27) and (28), that is, the inner boundary of the corridor is generated by the combined effect of the lift-to-drag ratio corresponding to the maximum angle of attack and the feasible range of longitudinal lift-to-drag ratio under process constraints. The outer boundary is divided into two parts. One part is generated by the combined effect of the lift-to-drag ratio corresponding to the minimum angle of attack and the feasible range of longitudinal lift-to-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 generated by the combined effect of the lift-to-drag ratio corresponding to the change from the minimum angle of attack to the maximum angle of attack and the feasible range of longitudinal lift-to-drag ratio, that is, the outer boundary of the reentry process constraints. In fact, for Figure 4 The upper boundary of the corridor can actually be understood as the upper boundary determined by the quasi-equilibrium gliding conditions, while its lower boundary corresponds to the reentry process constraints. When the longitudinal lift-to-drag ratio is lower than the lower boundary value of the corridor, since the available longitudinal lift of the aircraft is limited, in order to further reduce the lift-to-drag ratio, the drag acceleration can only be increased, which in turn causes the maximum overload, dynamic pressure and other process constraints to exceed the boundary values. Figure 5 The upper and lower boundaries of the middle corridor are actually symmetrical, and their values ​​are jointly determined by the maximum lift-to-drag ratio and the reentry process constraint value. Figure 6This provides a corridor with a lateral lift-to-drag ratio varying with the longitudinal lift-to-drag ratio when the normalized energy e = 0.6. Therefore, for the designed 3D profile to be feasible, it must be ensured that it is within the corridor constraints, especially the upper outer boundary of the corridor constrained by the reentry process. If it exceeds these constraints, the reentry process constraints will not be satisfied, leading to mission failure.

[0162] In summary, the essence of three-dimensional profile design is the allocation of lift-to-drag ratio in the longitudinal and lateral directions. The total lift-to-drag ratio is constant; a higher longitudinal allocation reduces the amount available for lateral motion adjustment, and vice versa. Compared to traditional two-dimensional profiles, three-dimensional profiles intuitively and clearly demonstrate the on-demand allocation of an aircraft's maneuverability.

[0163] As can be seen, the above method addresses the analytical prediction problem of reentry trajectories for hypersonic glide vehicles. Based on a reduced-order lateral energy state model and combined with a designed three-dimensional profile, it uniquely and analytically obtains the corresponding trajectory terminal landing point. Furthermore, to improve trajectory prediction accuracy, a piecewise analytical prediction method is proposed through coordinate polar transformation. This method ensures that real-time trajectory prediction requirements are met while also considering high accuracy, thus providing effective technical support for hypersonic glide vehicle trajectory planning and guidance methods.

[0164] This invention, based on quasi-equilibrium gliding conditions, constructs a three-dimensional lift-to-drag ratio corridor model for gliders by rationally selecting three-dimensional profile frame variables. This model comprehensively considers various process constraints, control constraints, and longitudinal and lateral motion requirements. Since it does not rely on pre-planned reference angle of attack or roll angle schemes and takes into account longitudinal and lateral motion requirements, the resulting three-dimensional flight corridor better reflects the inherent maneuverability boundary of the glider. Therefore, when using this flight corridor model for trajectory planning, it ensures that the obtained trajectory not only better utilizes the glider's high lateral maneuverability potential but also satisfies various reentry process constraints, ensuring trajectory feasibility. Thus, the method proposed in this invention can solve the problem of generating three-dimensional flight corridors for reentry trajectory planning of hypersonic gliders, reentry vehicles, and space-to-ground vehicles. This will not only drive the comprehensive development of related advanced aircraft platforms, weapons, sensors, and communication 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, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider, characterized in that, The method includes: Step S1: By analyzing the mapping relationship between the reentry process constraints and the motion model of the glider, determine the variables of the three-dimensional flight corridor model; Step S2: Based on the quasi-equilibrium gliding condition, the reentry process constraints are transformed into longitudinal sub-corridor model constraints; Step S3: Based on the longitudinal and lateral motion coupling relationship, construct longitudinal and lateral sub-corridor models; Step S4: Construct a three-dimensional flight corridor model by combining the longitudinal and lateral sub-corridor models; Step S5: Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control variables; Step S6: Set up the simulation scene and construct a three-dimensional lift-to-drag ratio corridor model for the glider; In step S1: Energy per unit mass of a glider for: in, Indicates the speed of the aircraft. The gravitational constant of Earth, This is the distance from the spacecraft's center of mass to the Earth's center; Introducing three-dimensional profile frame quantity ,in: in, , , These represent the longitudinal lift-to-drag ratio, the lateral lift-to-drag ratio, and the overall lift-to-drag ratio of the aircraft, respectively. These represent aerodynamic drag acceleration and lift acceleration, respectively. Indicates the tilt angle; The expression is: in, and These are the aerodynamic drag and lift coefficients of the glider, respectively, determined by the control variable angle of attack. ,high Aircraft speed or Mach number Decide; These represent the aerodynamic characteristic area and the aircraft mass, respectively. The density is atmospheric density; and: in, This represents the atmospheric density at sea level. Indicates the generalization height of atmospheric density; In step S2: The maximum dynamic pressure, maximum overload, and stagnation point heat flux density constraints during the reentry process are: in, These are the maximum permissible values ​​for stagnation heat flux density, dynamic pressure, and overload, respectively. Empirical constants for calculating heat flux density related to the overall aircraft were established. This represents the gravitational acceleration at sea level. For the reentry phase, the quasi-equilibrium gliding conditions are met: in, The flight path angle, The distance from the Earth's center. Represents lift acceleration. This indicates the quasi-equilibrium gliding tilt angle. Earth's gravitational acceleration; Constructing constraints for the vertical sub-corridor model: in, and This represents the minimum and maximum drag accelerations corresponding to the reentry process constraints; and These are the minimum and maximum longitudinal lift-to-drag ratios allowed by the reentry process constraints, respectively. In step S3: Based on the coupling relationship between longitudinal and lateral motion, given the longitudinal lift-to-drag ratio Lateral lift-to-drag ratio The amplitude is: in, Indicates the overall lift-to-drag ratio of the aircraft; for boundary values and Then we have: in, and These represent the minimum and maximum values ​​of the lateral lift-to-drag ratio, respectively. In step S4: Based on the constructed longitudinal and lateral sub-corridor models, with As a variable on the horizontal axis, its upper inner boundary on the vertical axis is: The upper boundary inside the vertical axis represents the angle of attack at its maximum value. Longitudinal lift-to-drag ratio maximum value The change in lateral lift-to-drag ratio The range of amplitude variation; The range of variation of the outer upper boundary is as follows: Where + indicates taking the union; Indicates angle of attack The change in longitudinal lift-to-drag ratio This represents the longitudinal lift-to-drag ratio, determined by process constraints.

2. The method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider according to claim 1, characterized in that, In step S5: Given energy By traversing all feasible angles of attack The corresponding three-dimensional flight corridor is determined, and the three-dimensional flight corridor simultaneously traverses all angles of attack based on quasi-equilibrium gliding conditions. and the magnitude of the tilt angle We obtain the following: The magnitude of the tilt angle satisfies: Among them, in the given In this case, The range of values ​​varies change.

3. The method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider according to claim 2, characterized in that, In the method, the glider is a CAV-H general-purpose hypersonic glider.

4. A system for constructing a three-dimensional lift-to-drag ratio corridor model of a glider, characterized in that, The system includes a processing unit configured to perform: By analyzing the mapping relationship between the reentry process constraints and the motion model of the glider, the variables of the three-dimensional flight corridor model are determined; among which: Energy per unit mass of a glider for: Indicates the speed of the aircraft. The gravitational constant of Earth, This is the distance from the spacecraft's center of mass to the Earth's center; Introducing three-dimensional profile frame quantity ,in: , , These represent the longitudinal lift-to-drag ratio, the lateral lift-to-drag ratio, and the overall lift-to-drag ratio of the aircraft, respectively. These represent aerodynamic drag acceleration and lift acceleration, respectively. Indicates the tilt angle; The expression is: and These are the aerodynamic drag and lift coefficients of the glider, respectively, determined by the control variable angle of attack. ,high Aircraft speed or Mach number Decide; These represent the aerodynamic characteristic area and the aircraft mass, respectively. The density is atmospheric density; and: This represents the atmospheric density at sea level. Indicates the generalization height of atmospheric density; Based on the quasi-equilibrium gliding condition, the reentry process constraints are transformed into longitudinal sub-corridor model constraints; where: The maximum dynamic pressure, maximum overload, and stagnation point heat flux density constraints during the reentry process are: These are the maximum permissible values ​​for stagnation heat flux density, dynamic pressure, and overload, respectively. Empirical constants for calculating heat flux density related to the overall aircraft were established. This represents the gravitational acceleration at sea level. For the reentry phase, the quasi-equilibrium gliding conditions are met: The flight path angle, The distance from the Earth's center. Represents lift acceleration. This indicates the quasi-equilibrium gliding tilt angle. Earth's gravitational acceleration; Constructing constraints for the vertical sub-corridor model: and This represents the minimum and maximum drag accelerations corresponding to the reentry process constraints; and These are the minimum and maximum longitudinal lift-to-drag ratios allowed by the reentry process constraints, respectively. Based on the coupling relationship between longitudinal and lateral motion, longitudinal and lateral sub-corridor models are constructed; where: Based on the coupling relationship between longitudinal and lateral motion, given the longitudinal lift-to-drag ratio Lateral lift-to-drag ratio The amplitude is: Indicates the overall lift-to-drag ratio of the aircraft; for boundary values and Then we have: and These represent the minimum and maximum values ​​of the lateral lift-to-drag ratio, respectively. A three-dimensional flight corridor model is constructed by combining longitudinal and lateral sub-corridor models; wherein: Based on the constructed longitudinal and lateral sub-corridor models, with As a variable on the horizontal axis, its upper inner boundary on the vertical axis is: The upper boundary inside the vertical axis represents the angle of attack at its maximum value. Longitudinal lift-to-drag ratio maximum value The change in lateral lift-to-drag ratio The range of amplitude variation; The range of variation of the outer upper boundary is as follows: + indicates taking the union of sets; Indicates angle of attack The change in longitudinal lift-to-drag ratio This represents the longitudinal lift-to-drag ratio, determined by process constraints. Establish the constraint mapping relationship between the three-dimensional flight corridor model and the control variables; Set up a simulation scenario and construct a three-dimensional lift-to-drag ratio corridor model for the glider.

5. An electronic device, characterized in that, The electronic device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider as described in any one of claims 1-3.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for constructing a three-dimensional lift-to-drag ratio corridor model of a glider as described in any one of claims 1-3.

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