Multi-gliding aircraft collaborative formation reentry trajectory rapid planning method

Abstract

The invention specifically relates to a rapid planning method for a reentry trajectory of a multi-gliding aircraft cooperative formation. The method comprises the following steps: predicting the arrival time, course angle and position adjustable range of a virtual aggregation point of each aircraft based on a space-time capability boundary prediction method; according to the arrival time, the course angle, the position and the formation configuration of the virtual aggregation point of each aircraft, determining the real aggregation point constraint of each aircraft; based on the coordination information, adaptively calculating a real aggregation point constraint value of each aircraft; taking the constraint value of the real gathering point of each aircraft as a terminal constraint, and planning the intersection gathering section trajectory of each aircraft based on a semi-analytical algorithm considering the obstacle avoidance constraint; performing trajectory planning on the leader based on a semi-analytical algorithm considering the obstacle avoidance constraint; and each follower generates a formation instruction through a progressive consistency control algorithm based on the height and course angle of the adjacent communicable aircraft, and realizes formation keeping section trajectory planning based on the formation instruction. Trajectory planning of a multi-gliding aircraft rendezvous and gathering section and a formation keeping section can be quickly realized.

Description

Technical Field

[0001] The present invention relates to the field of aircraft control technology, and in particular to a method for rapid planning of re-entry trajectories of a coordinated formation of multiple gliding aircraft. Background Art

[0002] The coordinated formation of multiple gliders can overcome the shortcomings of a single glider, such as the single mission execution type and weak penetration capability, and significantly improve the multi-task execution capability, penetration capability and anti-interference capability of the aircraft cluster. It is a necessary means to achieve coordinated tasks such as coordinated detection, coordinated penetration, and coordinated positioning. However, compared with fully driven aircraft such as cruise aircraft and drones, gliders have weaker control capabilities and lack effective means to control their speed. The under-driven characteristics of speed make it difficult for them to achieve strict formation flight. Relying solely on traditional coordinated reentry trajectory planning methods is no longer able to meet their stringent formation constraint requirements.

[0003] At present, the reentry trajectory can usually be divided into a rendezvous and assembly segment and a formation holding segment. During the rendezvous and assembly flight, each aircraft uses aerodynamic force to actively control the flight time and state, so that they tend to be consistent at the assembly point, thus forming a favorable formation situation; during the formation holding flight, each aircraft generates formation instructions based on its own state and formation reference information, so as to maintain the formation configuration until the task is handed over. However, the introduction of complex constraints such as assembly area and formation configuration makes the feasible domain of the coordinated formation reentry trajectory planning problem of underactuated gliding vehicles extremely small, and the difficulty of rapid solution is significantly increased. Therefore, it is necessary to carry out research on the rapid planning problem of coordinated reentry trajectory for assembly and formation flight.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The present invention provides a method for rapid re-entry trajectory planning of a multi-gliding aircraft coordinated formation, which can rapidly and efficiently implement trajectory planning for a rendezvous and assembly segment and a formation holding segment of the multi-gliding aircraft.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0007] According to a first aspect of the present invention, a method for rapid reentry trajectory planning of a multi-gliding aircraft cooperative formation is provided, the method comprising:

[0008] The trajectory planning of the intersection and assembly segment includes:

[0009] Predict the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point based on the space-time capability boundary prediction method; determine the real assembly point constraints of each aircraft based on the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; adaptively solve the real assembly point constraint values ​​of each aircraft based on the coordination information and the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point; use the real assembly point constraint values ​​of each aircraft as terminal constraints, and plan the rendezvous and assembly segment trajectories of each aircraft based on a semi-analytical algorithm that considers obstacle avoidance constraints;

[0010] The formation keeping segment trajectory planning includes:

[0011] The trajectory of the leader is planned based on a semi-analytical algorithm that takes obstacle avoidance constraints into consideration. Each follower generates formation instructions through an asymptotic consistency control algorithm based on the altitude and heading angle of the neighboring communicative aircraft. The trajectory planning of the formation holding segment is achieved based on the formation instructions.

[0012] In some exemplary embodiments, the adjustable range of the predicted arrival time of each aircraft at the virtual assembly point includes:

[0013] The aircraft range and time adjustable range are approximately a rhombus. When the position of the virtual assembly point is determined, the target range of the rendezvous and assembly section is also determined. At this time, the adjustable range of flight time is simplified to a straight line parallel to the time axis. The intersection of this straight line and the upper and lower boundaries of the rhombus is the adjustable range of arrival time of each aircraft at the assembly point when the position of the virtual assembly point is determined.

[0014] In some exemplary embodiments, predicting the adjustable range of the heading angle of each aircraft virtual assembly point includes:

[0015] The change in the sight angle between the segmentation point and the reentry point depends on the timing of the roll reversal. 0 ) case, the reentry trajectory corresponding to the maximum roll reversal timing obtains the adjustable range of the heading angle.

[0016] In some exemplary embodiments, the predicting the adjustable range of the virtual assembly point position of each aircraft includes:

[0017] Based on the adjustable formation azimuth angle, the adjustable range of the virtual assembly point of each aircraft is determined using the following formula:

[0018]

[0019] Among them, (λ VRP ,φ VRP ) is the virtual assembly point location, A VRP is the formation azimuth, S FMS is the formation range, R eis the radius of the Earth, φ f is the terminal latitude, λ f is the terminal longitude.

[0020] In some exemplary embodiments, the real assembly point constraints of each aircraft include altitude, speed, longitude, latitude, local ballistic inclination, heading angle, heading angle error and time constraints, and the specific form is as follows:

[0021]

[0022] In the formula, the subscript VRP represents the information related to the virtual assembly point, and the subscript RRP represents the information related to the real assembly point. and They are the altitude, speed, longitude, latitude, local ballistic inclination, heading angle and time constraint values ​​corresponding to the virtual assembly state. is the normalized energy at the real assembly point, f h,i (Γ), f λ,i (Γ), f φ,i (Γ) are the altitude, longitude and latitude corrections caused by the formation configuration Γ, ψ RRPLOS,i and are the line of sight angle at the actual assembly point and the line of sight angle error constraint value respectively.

[0023] In some exemplary embodiments, the semi-analytical algorithm based on obstacle avoidance constraints is specifically: improving the lateral planning part of the near-analytical gliding trajectory planning method considering the full-time and space state constraints, selecting one of the trajectories as the trajectory to be adjusted, and avoiding the collision by adjusting the last roll reversal timing before the collision point, including:

[0024] The flight trajectory between the collision point and the previous bank reversal position is defined as the collision avoidance adjustment segment;

[0025] By analyzing the collision process of the aircraft and the characteristics of the collision avoidance adjustment section, the collision avoidance adjustment section range S is selected. c ,average height Average speed Average roll angle amplitude Minimum safety distance p safe and reversal timing adjustment is the key parameter;

[0026] Traverse S c , and As a simulation condition, the position change Δp of the adjusted trajectory at the original collision point energy is obtained by trajectory simulation method;

[0027] The input for the build is S c , psafe and The output is interpolation table; finally, when trajectory adjustment is required, enter S c , p safe and Find and output the values ​​that satisfy Δp≥p safe Requested The reversal timing adjustment amount that satisfies the collision avoidance constraint can be obtained.

[0028] In some exemplary embodiments, trajectory planning is performed for the leader based on a semi-analytical algorithm that considers obstacle avoidance constraints, without considering terminal time and heading angle constraints.

[0029] According to a second aspect of the present invention, there is provided a system for rapid reentry trajectory planning of a multi-gliding aircraft coordinated formation, comprising a rendezvous and assembly segment planning module and a formation holding segment trajectory planning module;

[0030] The intersection and assembly segment trajectory planning module adopts a coordination-execution double-layer architecture for trajectory planning;

[0031] Among them, the coordination layer includes a spatiotemporal capability boundary prediction submodule and a coordination information adaptive solution submodule; the spatiotemporal capability boundary prediction submodule is used to predict the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point based on the spatiotemporal capability boundary prediction method; the coordination information adaptive solution submodule is used to determine the real assembly point constraints of each aircraft according to the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; based on the coordination information and the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point, the constraint value of each aircraft's real assembly point is adaptively solved; the execution layer includes an assembly trajectory planning submodule, which is used to use the real assembly point constraint value of each aircraft as the terminal constraint, and plan the rendezvous and assembly segment trajectory of each aircraft based on a semi-analytical algorithm considering obstacle avoidance constraints;

[0032] The formation holding segment trajectory planning module adopts a leader-follower collaborative architecture for trajectory planning;

[0033] Among them, the leader includes a leader trajectory planning submodule, which is used to plan the trajectory of the leader based on a semi-analytical algorithm that considers obstacle avoidance constraints; the follower layer includes a follower trajectory planning submodule, which is used to generate formation instructions based on the altitude and heading angle of the neighboring communicative aircraft through a progressive consistency control algorithm, and realize the formation holding segment trajectory planning based on the formation instructions.

[0034] The embodiment of the present invention provides a method for rapid planning of reentry trajectories for a multi-gliding aircraft cooperative formation, which is a two-stage cooperative reentry trajectory planning based on the "rendezvous assembly-formation maintenance" strategy. Theoretical analysis and simulation results show that:

[0035] (1) Compared with the existing methods for solving the problem of collaborative formation with small initial deviation, the proposed method is oriented to the mission planning level and proposes an IAFM flight plan and assembly formation algorithm framework. This framework takes into account the large initial reentry deviation and can quickly and efficiently realize the trajectory planning of the rendezvous and assembly phase and the formation holding phase of multiple gliding vehicles.

[0036] (2) Compared with the existing methods in which assembly points are uncontrollable or artificially divided, the proposed method embeds the prediction of the spatiotemporal capability boundaries of multiple aircraft into the adaptive solution of coordination information, which maximizes the adjustment capabilities of the aircraft and improves the success rate of coordinated formation flight.

[0037] (3) Compared with the existing methods for collaborative formation flight in the same altitude plane, the proposed method uses virtual altitude and heading angle as coordination information and realizes formation maintenance flight based on the consistency principle, which removes the restrictions on the longitudinal movement of each aircraft and enables it to basically maintain the formation configuration in different altitude planes.

[0038] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings herein are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification are used to explain the principles of the present invention. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0040] Figure 1 A schematic diagram schematically illustrates a flight scheme of an exemplary embodiment of the present invention;

[0041] Figure 2 A schematic diagram schematically shows the adjustable range of the flight time according to an exemplary embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a flow chart of a method for planning a trajectory for an underactuated aircraft formation assembly according to an exemplary embodiment of the present invention is schematically shown;

[0043] Figure 4 A schematic diagram schematically illustrates a glider aircraft communication topology according to an exemplary embodiment of the present invention;

[0044] Figure 5 The simulation result curve diagrams of the exemplary embodiment of the present invention are schematically shown: (a) ground trajectory; (b) three-dimensional trajectory of the formation holding segment; (c) altitude-time curve; (d) heading angle-time curve.

[0045] Figure 6 A schematic diagram of a trajectory planning system for underactuated aircraft formation assembly according to an exemplary embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0046] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present invention will be more comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0047] In addition, the accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0048] Existing related research results mostly focus on single aspects such as the trajectory planning method for the rendezvous and assembly phase or the trajectory planning method for the formation holding phase. There are few integrated planning methods for the coordinated reentry trajectory that comprehensively consider the assembly and formation flying, and there are the following shortcomings: (1) The essence of the trajectory planning method for the rendezvous and assembly phase is the reentry trajectory planning method that considers the full-state constraints of time and space. This method mainly includes methods based on trajectory optimization and methods based on the idea of ​​prediction-correction. Although the former has high terminal accuracy, due to the harsh problem constraints, this method has a strong dependence on the initial value and is difficult to converge efficiently and reliably; the latter is generally designed based on the equilibrium gliding assumption, resulting in a small adjustable range of flight time and terminal angle in this method, making it difficult to fully utilize the reentry capability of the aircraft and to achieve the formation handover requirements of the full-state constraints of terminal time and space. (2) Existing trajectory planning methods for the formation holding phase of reentry gliding aircraft mainly include methods based on control theory, multi-constraint trajectory optimization, and reinforcement learning. Among them, the method based on control theory has a faster speed in solving formation instructions, but it is usually difficult to meet the relative position constraints of the formation shooting direction, and can only meet the formation configuration constraints in the height direction and the lateral direction; while the method based on multi-constraint trajectory optimization has the disadvantages of taking a long time to calculate the trajectory and being difficult to apply online; the method based on reinforcement learning is difficult to adapt to complex and changeable mission scenarios, that is, the multi-task applicability is weak. (3) Existing research on trajectory planning and control of gliding cooperative formations is mostly based on good initial conditions for the formation to carry out formation control method design, that is, assuming that the initial formation state deviation is small, which cannot meet the needs of assembly formation under large-scale dispersion conditions; or because the performance of the formation assembly trajectory planning algorithm is poor, it is necessary to introduce a formation formation stage to further adjust the flight state to ensure smooth entry into the formation control stage.

[0049] This invention is based on the previous related research results "A near-analytical gliding trajectory planning method considering full-state constraints of space and time", and carries out corresponding planning framework and method research according to the requirements of cooperative formation missions of under-actuated gliding vehicles.

[0050] Aiming at the problem of cooperative formation of multiple reentry gliders, the present invention proposes a two-stage cooperative reentry trajectory planning method based on the "rendezvous assembly-formation keeping" strategy. First, according to the cooperative formation mission requirements and flight characteristics, the reentry trajectory is divided into the rendezvous assembly segment and the formation keeping segment. In the rendezvous assembly segment, a trajectory planning method based on the coordination-execution double-layer architecture is proposed, in which the coordination layer includes the space-time capability boundary prediction and coordination information adaptive solution links, which can realize the high-precision design and allocation of the real assembly point constraints before launch; the execution layer designs a reentry trajectory planning algorithm based on drag acceleration profile analytical prediction correction and two-stage roll reversal adaptive planning to meet the real assembly point space-time full state constraints and collision avoidance constraints. In the formation keeping segment, a consistent cooperative strategy based on the leader-follower architecture is adopted. The leader obtains the reentry trajectory that meets the terminal constraints through the proposed reentry trajectory planning algorithm, and the follower plans the trajectory by referring to the altitude and heading angle of the adjacent communicable aircraft through the progressive consistency control algorithm, thereby realizing long-range formation keeping.

[0051] Without loss of generality, the embodiments of the present invention make the following long-range assembly and formation scene settings: 1) The target formation area is set to be a circle with the mission handover point as the center and the formation range as the radius; 2) The initial position of each aircraft in the formation holding section is set as the real assembly point, and the area surrounded by the real assembly point of each aircraft is the formation assembly area, and its geometric center is the virtual assembly point; 3) Each aircraft is set to have completed the initial re-entry state, mission handover point state, formation range and formation azimuth information binding before re-entry; 4) The collaborative formation task requires multiple re-entry gliding aircraft to depart from their respective re-entry points, form a formation configuration and formation speed conditions in the designated formation assembly area, and maintain the configuration to fly to the mission handover area.

[0052] Under the above mission scenario setting, in order to solve the problem of coordinated formation of gliding aircraft, the present invention designs a rendezvous and assembly and formation-keeping flight scheme. Figure 1 As shown in the figure, the scheme divides the reentry formation flight of each glider into the initial descent segment, the rendezvous and assembly segment, and the formation holding segment, and defines the segmentation points between the initial descent segment and the rendezvous and assembly segment, and between the rendezvous and assembly segment and the formation holding segment as the conversion point and the real assembly point, respectively. Among them, the initial descent segment is a transition flight stage between the reentry point and the conversion point. The aerodynamic force in this stage is weak, the control ability is poor, and it is not suitable for large-scale maneuvering adjustments. During the rendezvous and assembly flight, each aircraft uses aerodynamic force to achieve active regulation of flight time and state, thereby satisfying the real assembly point constraint conditions and forming an initial formation situation. During the formation holding flight, each aircraft generates formation instructions based on its own state and formation reference information, thereby maintaining the formation configuration until the mission handover is completed.

[0053] Based on the flight plan formulated above, the present invention designs a collaborative formation trajectory planning method framework, which is divided into three parts: initial descent phase, rendezvous and assembly phase, and formation holding phase trajectory planning, as follows:

[0054] In the initial descent trajectory planning part, a constant roll angle strategy is used to perform open-loop control on the aircraft. TP When , the aircraft is considered to have entered the rendezvous and assembly flight phase.

[0055] In the trajectory planning part of the rendezvous and assembly section, a assembly trajectory planning method based on a coordination-execution two-layer architecture is designed. Among them, the coordination layer includes two modules: space-time capability boundary prediction and coordination information adaptive solution. First, based on the space-time capability boundary prediction method, the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point are quickly predicted; on this basis, the space-time adjustment capability of each aircraft and the formation mission requirements are comprehensively considered, and the real assembly point constraints of the formation are determined through the coordination information adaptive solution link. The execution layer designs a assembly trajectory planning algorithm based on drag acceleration profile analytical prediction correction and dual-stage roll reversal adaptive adjustment to receive the real assembly point constraint information of each aircraft and realize high-precision assembly of multiple aircraft, providing favorable initial conditions for formation maintenance.

[0056] In the formation holding phase trajectory planning part, a trajectory planning method based on leader-follower collaborative architecture and asymptotic consistency theory is designed. The leader uses the proposed reentry trajectory planning algorithm to generate a formation holding phase trajectory that satisfies the precise arrival at the mission handover point; each follower uses the altitude and heading angle of the neighboring communicable aircraft as reference information, and generates formation instructions through the asymptotic consistency control algorithm to maintain the formation configuration for a long time, thereby realizing formation trajectory planning.

[0057] The motion model of the aircraft is described as follows:

[0058] Assuming that the earth is a rotating sphere and that all aircraft are of the same model, a dimensionless three-DOF center-of-mass dynamics model with energy as the independent variable is established as follows:

[0059]

[0060] Where, the subscript i = 1, 2, ..., N is the number of the formation aircraft, and the dimensionless state quantity in formula (1) is x = [r, θ, φ, V, γ, ψ] T , where r is the dimensionless distance from the center of the earth, θ is the longitude of the center of the earth, φ is the latitude of the center of the earth, V is the dimensionless velocity, γ is the local ballistic inclination, ψ is the track yaw angle, and υ is the roll angle. L and D are the dimensionless lift acceleration and drag acceleration, which are the lift coefficient C L and the drag coefficient C DThe above aerodynamic coefficients are functions of the height h and the Mach number Ma, where the Mach number Ma can be calculated from the current height and speed, C γ,i , C ψ,i , and is an additional term caused by the rotation of the Earth.

[0061] The constraint model of the aircraft is described as follows:

[0062] Taking into account the collaborative formation mission mode and the characteristics of the gliding vehicle, the trajectory planning method needs to be designed to meet the constraints of both the single vehicle and the assembly formation.

[0063] Among them, the single aircraft constraints include process constraints, assembly formation, control constraints and terminal constraints, specifically:

[0064] (1) Process Constraint Assembly Formation

[0065] The process constraints mainly include the stagnation point heat flux density Dynamic pressure q i , Overload n i and balanced gliding conditions, specifically:

[0066]

[0067] In the formula, k Q is the heat flux coefficient, g 0 is the gravitational acceleration at sea level, q max and n max are the corresponding constraint peaks, σ QEGC To balance the gliding roll angle, it is uniformly set to 0°. Among them, the first three constraints are hard constraints, while the balanced gliding condition is a soft constraint that does not need to be strictly satisfied.

[0068] To facilitate the subsequent profile design, the initial and terminal energies of the i-th spacecraft’s reentry phase are assumed to be E 0,i and E f,i , for the dimensionless energy E i Normalization is performed, that is, The normalized energies of the initial and terminal reentry segments are and On this basis, equation (2) is converted into resistance acceleration D i About Normalized Energy The functional relationship of and Then the boundary of the DE profile reentry corridor can be determined by the following formula:

[0069]

[0070] In the formula, are the upper and lower boundaries of the reentry corridor, respectively. Therefore, equation (3) can be transformed into the drag acceleration constraint:

[0071]

[0072] (2) Control constraints

[0073] The control constraint aims to limit the angle of attack α i With the tilt angle σ i Amplitude, that is:

[0074] α min ≤α i ≤α max ,σ min ≤|σ i |≤σ max (5)

[0075] In the formula, α min , α max , σ min and σ max They are the upper and lower limits of the attack angle and roll angle amplitude respectively.

[0076] Taking into account the thermal protection and range requirements of the glider, the three-stage linear angle of attack profile is designed as follows:

[0077]

[0078] In the formula, α max , α L / Dmax are the maximum flight angle of attack and the maximum lift-to-drag ratio angle of attack respectively; V a 、V b is the angle of attack profile segmentation parameter.

[0079] (3) Terminal constraints

[0080] The leader terminal constraints include the mission handover point altitude, speed, longitude, latitude, local ballistic inclination and heading angle error constraints, and their specific forms are as follows:

[0081]

[0082] In the formula, ψ fLOS is the terminal sight angle, and are the corresponding terminal constraint values. It is worth noting that since the main flight mission of the follower is to maintain the formation configuration, no strict terminal constraints are set for it.

[0083] Among them, the assembly formation constraints are as follows:

[0084] In addition to the basic single-vehicle constraints, each aircraft must also meet assembly formation constraints during formation flight, which mainly include assembly point constraints, assembly process constraints and formation process constraints, as follows.

[0085] (1) Assembly point constraints

[0086] In order to improve the efficiency of solving the real assembly point constraints of each aircraft, the present invention uses the virtual assembly point constraints as a link to build a connection between the collaborative formation task and the real assembly point constraints of each aircraft. Among them, the virtual assembly point constraint value can be comprehensively determined based on the formation segment range requirements and the rendezvous segment flight capability; the real assembly point constraint value of each aircraft is comprehensively determined based on the virtual assembly point constraint value and the formation configuration.

[0087] The virtual assembly point constraints include the virtual assembly point altitude, speed, longitude, latitude, local ballistic inclination, heading angle and time constraints, and their specific forms are as follows:

[0088]

[0089] In the formula, the subscript VRP represents the information related to the virtual assembly point. and are the corresponding constraint values ​​of the virtual assembly states respectively.

[0090] It is worth noting that, affected by the formation configuration, the position constraints of the real assembly points of each aircraft are not exactly the same as the position constraints of the virtual assembly points, and they need to be corrected according to the geometric relationship of the formation configuration to obtain accurate constraint values. Here, the formation configuration function is defined as Γ, and the real assembly point constraints of each aircraft include altitude, speed, longitude, latitude, local ballistic inclination, heading angle, heading angle error and time constraints, and their specific forms are as follows:

[0091]

[0092] In the formula, the subscript RRP represents the real assembly point related information, is the normalized energy at the real assembly point, f h,i (Γ), f λ,i (Γ), f φ,i (Γ) are the altitude, longitude and latitude corrections caused by the formation configuration Γ, ψ RRPLOS,i and are the line of sight angle at the actual assembly point and the line of sight angle error constraint value respectively.

[0093] (2) Constraints on the Aggregation Process

[0094] Considering the flight safety during the dynamic assembly process, each aircraft must meet the following collision avoidance constraints during the rendezvous and assembly phase:

[0095]

[0096] In the formula, the subscript IAS represents the information related to the intersection and assembly segment. is the normalized energy during the flight process; Δp i is the relative position vector between any two aircraft; p safe The minimum safe position to avoid collision can be given according to the aircraft structure size and mission requirements.

[0097] (3) Formation process constraints

[0098] During the formation holding phase, the distance between formations is usually much larger than the size of the aircraft itself, so when the formation configuration holding algorithm works normally, there is almost no collision accident between the aircraft. Therefore, during the formation holding phase, the present invention mainly considers the following formation process constraints:

[0099]

[0100] In the formula, the subscript FMS represents the relevant information of the rendezvous and assembly segment. is any normalized energy during formation flying; ΔV i and Δp i are the velocity vector and position vector between any two aircraft, Represents Δp i The expected value can be determined based on the expected formation configuration; ε p , ε V are the relative position and velocity vector error limits respectively.

[0101] Based on the previous related research results "A Nearly Analytical Gliding Trajectory Planning Method Considering Space-Time Full State Constraints", this invention proposes a reentry trajectory planning method that satisfies both space-time full state constraints and collision avoidance constraints, which can be used as the basic algorithm for subsequent rendezvous and assembly phase trajectory planning and formation holding phase leader trajectory planning. The following only introduces the improved content based on "A Nearly Analytical Gliding Trajectory Planning Method Considering Space-Time Full State Constraints".

[0102] In order to deal with the possible collision problem during the assembly process, the present invention proposes a semi-analytical reentry trajectory fast planning algorithm considering collision avoidance constraints. The following improvements are made to the lateral planning part of the previous research results - the nearly analytical gliding trajectory planning method considering the full-state constraints of space and time:

[0103] After completing the trajectory planning, if it is detected that there is a risk of collision between the two aircraft trajectories, one of the trajectories can be selected as the trajectory to be adjusted, and the collision can be avoided by fine-tuning the timing of the previous bank reversal of the collision point. The specific method is as follows. First, define the flight trajectory between the collision point and the previous bank reversal position as the collision avoidance adjustment segment; second, by analyzing the characteristics of the aircraft collision process and the collision avoidance adjustment segment, select the collision avoidance adjustment segment range S c ,average height Average speed Average roll angle amplitude Minimum safety distance p safe and reversal timing adjustment is the key parameter; then, traverse S c , and As the simulation condition, a large number of trajectory simulation methods are used to obtain the position change Δp of the adjusted trajectory at the original collision point energy; on this basis, the input is constructed as S c , p safe and The output is interpolation table; finally, when trajectory adjustment is required, enter S c , p safe and Find and output the values ​​that satisfy Δp≥p safe Requested The reversal timing adjustment amount that satisfies the collision avoidance constraint can be obtained.

[0104] The improved trajectory planning method obtains a reference profile that satisfies the terminal altitude, speed, local ballistic inclination, range and time constraints through longitudinal analytical planning, and generates a lateral trajectory that satisfies the terminal position and heading constraints through lateral planning, and then generates a three-degree-of-freedom trajectory that satisfies the terminal constraints in the form of (9) through trajectory iterative correction. For the reentry trajectory planning problem with terminal constraints in the form of formula (7), that is, it is not necessary to satisfy the terminal time and heading angle constraints, the improved longitudinal planning can be simplified to a single-parameter profile form, the lateral planning can be simplified to a heading angle error corridor method, and the trajectory iterative correction strategy can be simplified to only correct the range error without considering collision avoidance.

[0105] A fast reentry trajectory planning method for multi-gliding vehicle cooperative formation, such as Figure 3 As shown, it includes trajectory planning for the rendezvous and assembly phase and trajectory planning for the formation keeping phase:

[0106] The trajectory planning of the rendezvous and assembly segment includes:

[0107] Predict the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point based on the space-time capability boundary prediction method; determine the real assembly point constraints of each aircraft based on the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; adaptively solve the real assembly point constraint values ​​of each aircraft based on the coordination information and the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point; use the real assembly point constraint values ​​of each aircraft as terminal constraints, and plan the rendezvous and assembly segment trajectories of each aircraft based on a semi-analytical algorithm that considers obstacle avoidance constraints;

[0108] Formation keeping trajectory planning includes:

[0109] The trajectory of the leader is planned based on a semi-analytical algorithm that takes obstacle avoidance constraints into consideration. Each follower generates formation instructions based on the altitude and heading angle of the neighboring communicative aircraft through an asymptotic consistency control algorithm, and implements trajectory planning for the formation holding segment based on the formation instructions.

[0110] Below, each step of the phased array radar design method in this example implementation will be described in more detail with reference to the accompanying drawings and embodiments.

[0111] In the trajectory planning of the rendezvous and assembly phase, the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point are predicted based on the spatiotemporal capability boundary prediction method.

[0112] For example, the flight capability boundary of each aircraft at the virtual assembly point is the basis for solving the subsequent coordination information, and is also the key to providing a good initial state of the formation and improving the success rate of the formation. Taking into account the task requirements of the coordinated formation, the computational cost and the importance of the parameters, the present invention selects the time t for each aircraft to arrive at the virtual assembly point VRP,i , heading angle ψ VRP,i and position (λ VRP,i ,φ VRP,i ) adjustable range represents its flight capability. VRP,i , VRP,i and (λ VRP,i ,φ VRP,i ) A quick prediction method is used to provide a selection range for subsequent coordination information solution. The specific method is as follows.

[0113] (1) Quick prediction of adjustable time range

[0114] From the above semi-analytical reentry trajectory fast planning algorithm considering collision avoidance constraints, it can be seen that for a glider with certain mission conditions, its range and time are only k 1 , k 2 function, that is, any set of k 1 , k 2There is a set of S and t corresponding to each of them. When the aircraft flies along the upper boundary of the corridor, its trajectory corresponds to the shortest range and flight time, that is, On the contrary, when flying along the lower boundary of the corridor, its trajectory corresponds to the longest range and flight time.

[0115] Therefore, by traversing k 1 , k 2 The method can quickly obtain the adjustable range of each aircraft's range and flight time. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that the range and time adjustable range of the aircraft are approximately a rhombus. When the virtual assembly point is determined, the target range of the rendezvous and assembly section is also determined. At this time, the adjustable range of flight time is simplified to a straight line parallel to the time axis, as shown by the black solid line in the figure. The intersection of this straight line and the upper and lower boundaries of the rhombus can be roughly regarded as the adjustable range of assembly time of each aircraft when the virtual assembly point is determined [t VRPmin,i ,t VRPmax,i ].

[0116] (2) Quick indication of the adjustable heading angle range

[0117] From the above semi-analytical reentry trajectory fast planning algorithm considering collision avoidance constraints, it can be seen that during the rendezvous and assembly phase, the segmentation points Compared to reentry point Change in sight angle Depends on the timing of the roll reversal size. The larger the value, the longer the lateral maneuvering time of the aircraft in a certain direction, the larger the corresponding lateral distance, and the greater the change in the line of sight angle. Therefore, Δψ LOS,0S About Therefore, by planning different initial roll angle signs sgn(σ 0 ) case, the reentry trajectory corresponding to the maximum roll reversal timing obtains the adjustable range of heading angle [ψ VRPmin,i ,ψ VRPmax,i ]. At this point, the adjustable range of the heading angle of each aircraft when the virtual assembly point position is determined can be obtained.

[0118] (3) Rapid prediction of the adjustable range of the virtual assembly point

[0119] From the above analysis, it can be seen that when the mission conditions and the position of the virtual assembly point are determined, the flight time and the adjustable range of the heading angle at the virtual assembly point can be quickly predicted. However, how to determine the position of the virtual assembly point is often a complex and sensitive issue. To this end, the present invention proposes a method for predicting the adjustable range of the virtual assembly point position based on the above-mentioned method for predicting the adjustable range of the angle, which can provide a theoretical basis and selection range for setting mission conditions.

[0120] Define the assembly azimuth as the task handover point Relative to the spherical azimuth of the virtual assembly point, the position of the given task handover point and the formation range S FMS In this case, the adjustable range of the virtual assembly point position is an arc on the boundary of the target detection area, and the virtual assembly point position is only related to the formation azimuth A. VRP So we can find A VRP The adjustable range is then used to obtain the adjustable range of the virtual assembly point position, and the specific method is as follows.

[0121] In A VRP Under certain circumstances, the position of the virtual assembly point can be calculated using the spherical geometry formula, and the above-mentioned heading angle adjustable range prediction algorithm can be used to quickly obtain [ψ VRPmin,i ,ψ VRPmax,i ]. In order to make the intersection of the adjustable ranges of the heading angles of each aircraft at the corresponding virtual assembly point a non-empty set, and to be able to smoothly enter the heading angle error corridor of the formation holding phase, we have:

[0122]

[0123] In the formula, [ψ min ,ψ max ] is A VRP The adjustable range of the heading angle of the virtual assembly point under certain conditions, Δψ bF1 is the initial width of the heading angle error corridor in the formation holding phase. Therefore, equation (12) can be used as a feasibility criterion for the formation azimuth or virtual assembly point position to screen feasible formation azimuth and virtual assembly point position. On this basis, the following process can be used to find the adjustable range of the formation azimuth [A VRPmin ,A VRPmax ]:

[0124] Step 1: Set the spherical azimuth of the mission handover point relative to the reentry point of each aircraft to The average reentry azimuth is calculated as And let the initial formation azimuth be

[0125] Step 2: Change A at equal intervals in a clockwise direction VRP , and judge the current A in turn VRPWhether it satisfies formula (12) until the first infeasible formation azimuth is encountered, and the last feasible formation azimuth is recorded as A VRPmax ;

[0126] Step 3: Change A at equal intervals in a counterclockwise direction VRP , and judge the current A in turn VRP Whether it satisfies formula (12) until the first infeasible formation azimuth is encountered, and the last feasible formation azimuth is recorded as A VRPmin .

[0127] So far, the rapid prediction of the adjustable range of the formation azimuth has been completed. After the following geometric calculation, the corresponding virtual assembly point position (λ VRP ,φ VRP )Adjustable range:

[0128]

[0129] In the trajectory planning of the rendezvous and assembly phase, the constraints of each aircraft's real assembly point are adaptively solved based on the coordination information and the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point;

[0130] For example, the assembly point constraint design is the key point connecting the rendezvous assembly section and the formation maintenance section, which directly determines the feasibility of assembly trajectory planning and the formation configuration maintenance effect. To this end, the present invention selects the virtual assembly point flight time t VRP With the full state vector x VRP =[h VRP ,λ VRP ,φ VRP ,V VRP ,γ VRP ,ψ VRP ] as the first-level coordination information; the actual assembly point flight time of each aircraft With the full state vector As the second-level coordination information, the first-level and second-level coordination information are quickly solved through an adaptive method, as follows.

[0131] (1) First-level coordination information solution method

[0132] a.λ VRP ,φ VRP Solution method

[0133] Before the coordinated formation mission is executed, the space-time capability boundary can be used to quickly predict the adjustable range of the formation heading angle and the virtual assembly point position, and the formation azimuth angle A can be selected according to the actual mission requirements. VRP and the virtual assembly point position (λ VRP ,φ VRP ).

[0134] B V VRP Solution method

[0135] Considering that each aircraft has almost the same assembly state and the flight trajectory of the formation holding stage is relatively stable, it can be considered that the aerodynamic parameters of each aircraft in the formation holding stage have a small variation range, and the lift-to-drag ratio of each aircraft can be approximated as a constant value (L / D) VRP According to the formation range requirement and range estimation formula, the formation range can be expressed as:

[0136]

[0137] It can be deduced that V VRP for:

[0138]

[0139] Where K = 2S FMS / R e (L / D) VRP .

[0140] ch VRP Solution method

[0141] Using formula (15) to get V VRP On the basis of the approximate solution, in order to further ensure that each aircraft has sufficient energy at the virtual assembly point to support its formation holding flight mission, the following method is designed to determine the energy E at the virtual assembly point: VRP With height h VRP .

[0142] Firstly, considering the computational efficiency and trajectory form approximation comprehensively, the leader aircraft is taken as the planning object, and Equation (7) is the terminal constraint. A simplified version of the near-analytical gliding trajectory planning method considering the full-state constraints of space and time is used to construct an approximate trajectory. Secondly, in the range-energy profile of the approximate trajectory, the waiting range S is intercepted. togo =S FMS The corresponding energy in this case is considered as E VRP ; Finally, V VRP Substituting into the dimensionless energy expression E = V 2 / 2-1 / r, we can solve and get h VRP .

[0143] d.γ VRP Solution method

[0144] In addition, in order to enhance the range capability of the formation, γ VRP Equal to the equilibrium glide path angle γ QEGC , then:

[0145]

[0146] Where D VRP is the dimensionless drag acceleration at the virtual assembly point, V VRP 、h VRP OK; 1 and a 2 is the physical quantity related to the state of the virtual assembly point, and its specific expression is as follows:

[0147]

[0148] et VRP Solution method

[0149] After the location of the virtual assembly point is determined, the time and space capability boundary can be used to quickly predict the time for each aircraft to arrive at the virtual assembly point. The adjustable range is [t VRPmin,i ,t VRPmax,i ], and thus t is determined by the following formula VRP Adjustable range:

[0150]

[0151] In actual missions, the success rate of formation assembly is often the primary consideration. Therefore, the middle value of the adjustable range is selected as the coordinated flight time, that is, t VRP =(t min +t max ) / 2. If the adjustable time ranges of each aircraft have no intersection, that is, t VRP If it does not exist, then the equation (18) can be established by adjusting the reentry time of each spacecraft.

[0152] f.ψ VRP Solution method

[0153] After determining the location of the virtual assembly point, similar to equation (18), considering the adjustment capability of each aircraft and the flight capability of the formation holding phase, determine ψ VRP The adjustable range is:

[0154] [ψ min ,ψ max ]=[ψ VRPmin ,ψ VRPmax ]∩[A VRP -Δψ bF1 ,A VRP +Δψ bF1 ] (19)

[0155] In order to improve the convergence of the trajectory planning algorithm in the intersection and assembly stage, ψ VRP It can be further taken as [ψ min ,ψ max ]Intermediate value ψVRP =(ψ min +ψ max ) / 2.

[0156] (2) Secondary coordination information solution method

[0157] After obtaining the above-mentioned first-level coordination information, the formation configuration function Γ can be substituted into equation (9) to quickly solve the second-level coordination information of each aircraft, that is, the real assembly point constraint. So far, the high-precision, adaptive solution and allocation of the real assembly point constraints of each aircraft have been completed.

[0158] Exemplarily, the real assembly point constraint value of each aircraft is used as the terminal constraint, and the rendezvous and assembly segment trajectory of each aircraft is planned based on a semi-analytical algorithm considering obstacle avoidance constraints.

[0159] Assembly trajectory planning is the basis for achieving high-precision assembly of multiple aircraft, and is also an important link in providing a good initial state for the formation holding phase. As the execution layer, after receiving the real assembly point constraints of each aircraft, the assembly trajectory planning link can quickly realize the rendezvous and assembly segment trajectory planning of each aircraft through a semi-analytical algorithm based on obstacle avoidance constraints.

[0160] In the trajectory planning of the rendezvous and assembly phase, the trajectory planning of the leader is carried out based on a semi-analytical algorithm considering obstacle avoidance constraints.

[0161] For example, the leader can implement trajectory planning by a semi-analytical algorithm based on obstacle avoidance constraints. However, unlike the rendezvous and assembly phase, the leader of the formation holding phase does not need to consider the terminal time and heading angle constraints, so a simplified version of the semi-analytical algorithm based on obstacle avoidance constraints can be used for trajectory planning.

[0162] In the trajectory planning of the rendezvous and assembly phase, each follower generates formation instructions through a progressive consistency control algorithm based on the altitude and heading angle of the adjacent communicative aircraft, and implements the trajectory planning of the formation holding phase based on the formation instructions.

[0163] Exemplarily, the follower uses the trajectory of the neighboring communicative aircraft as reference information and uses the asymptotic consistency theory to generate a formation trajectory to achieve long-distance formation maintenance. The specific method is as follows.

[0164] After the intersection and convergence is completed, each follower can achieve formation maintenance and trajectory planning based on the state information of the neighboring communicable aircraft through the theory of asymptotic consistency, while satisfying various process constraints. Taking into account the difficulty and physical significance of state measurement during actual flight, this embodiment selects the virtual altitude and heading angle ψ i As the longitudinal and lateral coordination variables, respectively, Δh i is the expected relative height determined by the formation configuration. When the virtual heights are consistent, then With h i -h j =Δh i -Δh j , that is, the height distance between aircraft i and aircraft j is Δh i -Δh j .

[0165] First, for the longitudinal plane, consider the first and second order derivatives of the virtual height with respect to time as follows:

[0166]

[0167] On this basis, the second-order consistency theory is applied to design the virtual control input as:

[0168]

[0169] In the formula, is the control gain. Under the control law, each aircraft and can achieve asymptotic consistency, thus forming a longitudinal formation. Further, it can be obtained that the actual control input angle of attack α of each aircraft is i With the tilt angle σ i The equation should be satisfied Solving the above equations yields the required longitudinal component of lift (L i cosσ i ) c for:

[0170]

[0171] Secondly, for the lateral plane, consider the first-order derivative of the heading angle with respect to time as follows:

[0172]

[0173] On this basis, the first-order consistency theory is applied to design the virtual control input as:

[0174]

[0175] In the formula, K ψ1 >0 is the control gain. Similarly, under the control law, each aircraft ψ i can achieve asymptotic consistency, thus forming a lateral formation. Further, it can be obtained that the actual control input angle of attack α of each aircraft is i With the tilt angle σ i It should also satisfy the equation Solving the above equations yields the required lateral component of lift (L i sinσ i ) c for:

[0176] (L i sinσ i ) c =u ψi V i cosγ i (25)

[0177] Finally, according to the inherent properties of reentry gliding, the actual control input of each aircraft can be given by the following formula:

[0178]

[0179] The α calculated from the above formula i With σ i Substituting into the equation of motion and performing numerical integration, the trajectory of the follower formation can be obtained.

[0180] As another aspect, the present application also provides a system for rapid reentry trajectory planning of a multi-gliding aircraft coordinated formation, such as Figure 6 As shown, it includes a rendezvous and assembly segment planning module and a formation maintaining segment trajectory planning module.

[0181] The trajectory planning module of the rendezvous and assembly segment adopts a coordination-execution two-layer architecture for trajectory planning;

[0182] Among them, the coordination layer includes a spatiotemporal capability boundary prediction submodule and a coordination information adaptive solution submodule; the spatiotemporal capability boundary prediction submodule is used to predict the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point based on the spatiotemporal capability boundary prediction method; the coordination information adaptive solution submodule is used to determine the real assembly point constraints of each aircraft according to the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; based on the coordination information and the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point, the constraint value of each aircraft's real assembly point is adaptively solved; the execution layer includes an assembly trajectory planning submodule, which is used to use the real assembly point constraint value of each aircraft as the terminal constraint, and plan the rendezvous and assembly segment trajectory of each aircraft based on a semi-analytical algorithm considering obstacle avoidance constraints;

[0183] The trajectory planning module of the formation-keeping phase adopts a leader-follower collaborative architecture for trajectory planning;

[0184] Among them, the leader includes a leader trajectory planning submodule, which is used to plan the trajectory of the leader based on a semi-analytical algorithm that considers obstacle avoidance constraints; the follower layer includes a follower trajectory planning submodule, which is used to generate formation instructions based on the altitude and heading angle of the neighboring communicative aircraft through a progressive consistency control algorithm, and realize the formation holding segment trajectory planning based on the formation instructions.

[0185] The simulation verification of the above-mentioned multi-glider coordinated formation re-entry trajectory rapid planning method is as follows:

[0186] In an exemplary embodiment, a formation mission scenario simulation in a plumb plane is carried out using CAV-H as a model to verify the feasibility, rapidity, and multi-task applicability of the proposed flight scheme and algorithm framework. The number of formation aircraft N is set to 3, the formation configuration is an isosceles triangle with a base length of 10 km and a height of 3 km, and the formation range S FMS = 800km, where aircraft 1 is the leader, aircraft 2 and 3 are followers, and the communication topology between aircraft is as follows: Figure 4 The initial and terminal position constraints of each aircraft are set as shown in Table 1. The initial state of each aircraft is set to: t 0 =0s,h 0 =75km, V 0 =6500m / s,γ 0 =-0.1°, ψ 0 is the azimuth of the virtual assembly point relative to the reentry point. The leader terminal state constraint is set as: The process constraints are set to q max =100kPa and n max =3. The preset angle of attack profile and angle of attack constraint are set to α min =5°, α maxLD =10°, α max =20°, V a =5000m / s, V b =4000m / s. The heel angle constraint is σ min =0°,σ max =80°, |σ 0 |=5°. The mid-shift handover distance is 30km. All simulations are completed on a desktop computer equipped with an Intel Core i7-8700 3.20GHz Intel processor, and the simulation environment is the VisualStudio 2019 platform.

[0187] Table 1 Initial and terminal positions of each aircraft

[0188]

[0189] Based on the above simulation conditions, the trajectory planning results of multi-gliding aircraft cooperative formation are obtained as follows: Figure 5 As shown. Figure 5 From (a) and (b), we can see that when assembling in formation at different altitude planes, each aircraft can still achieve high-precision assembly before the formation, and maintain the basic formation configuration in the formation holding phase until the leader accurately arrives at the middle and end handover positions. Figure 5From (c) and (d), we can see that the follower can closely track the leader’s altitude and heading angle throughout the formation holding phase, thus maintaining effective formation flight.

[0190] Other embodiments of the invention will readily occur to those skilled in the art after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0191] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for rapid reentry trajectory planning of a multi-gliding aircraft coordinated formation, characterized in that: The method includes trajectory planning for the rendezvous and assembly phase and trajectory planning for the formation-keeping phase: The trajectory planning of the intersection and assembly segment includes: Predict the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point based on the space-time capability boundary prediction method; determine the real assembly point constraints of each aircraft based on the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; adaptively solve the real assembly point constraint values ​​of each aircraft based on the coordination information and the arrival time, heading angle and adjustable position range of each aircraft's virtual assembly point; use the real assembly point constraint values ​​of each aircraft as terminal constraints, and plan the rendezvous and assembly segment trajectories of each aircraft based on a semi-analytical algorithm that considers obstacle avoidance constraints; The formation keeping segment trajectory planning includes: The trajectory of the leader is planned based on a semi-analytical algorithm that takes obstacle avoidance constraints into consideration. Each follower generates formation instructions based on the altitude and heading angle of the neighboring communicative aircraft through an asymptotic consistency control algorithm, and implements trajectory planning for the formation holding segment based on the formation instructions.

2. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 1, characterized in that: The adjustable range of the predicted arrival time of each aircraft virtual assembly point includes: The aircraft range and time adjustable range are approximately a rhombus. When the position of the virtual assembly point is determined, the target range of the rendezvous and assembly section is also determined. At this time, the adjustable range of flight time is simplified to a straight line parallel to the time axis. The intersection of this straight line and the upper and lower boundaries of the rhombus is the adjustable range of arrival time of each aircraft at the assembly point when the position of the virtual assembly point is determined.

3. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 2, characterized in that: The predicted adjustable range of the heading angle of each aircraft virtual assembly point includes: The change in the sight angle between the segmentation point and the reentry point depends on the size of the roll reversal opportunity. The adjustable range of the heading angle is obtained by planning the reentry trajectory corresponding to the maximum roll reversal opportunity under different initial roll angle signs sgn(σ0).

4. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 3, characterized in that: The predicted adjustable range of the virtual assembly point position of each aircraft includes: Based on the adjustable formation azimuth angle, the adjustable range of the virtual assembly point of each aircraft is determined using the following formula: Among them, (λ VRP ,φ VRP ) is the virtual assembly point location, A VRP is the formation azimuth, S FMS is the formation range, R e is the radius of the Earth, φ f is the terminal latitude, λ f is the terminal longitude.

5. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 4, characterized in that: The actual assembly point constraints of each aircraft include altitude, speed, longitude, latitude, local ballistic inclination, heading angle, heading angle error and time constraints, and the specific form is as follows: In the formula, the subscript VRP represents the information related to the virtual assembly point, and the subscript RRP represents the information related to the real assembly point. and They are the altitude, speed, longitude, latitude, local ballistic inclination, heading angle and time constraint values ​​corresponding to the virtual assembly state. is the normalized energy at the real assembly point, f h,i (Γ), f λ,i (Γ), f φ,i (Γ) are the altitude, longitude and latitude corrections caused by the formation configuration Γ, ψ RRPLOS,i and are the line of sight angle at the actual assembly point and the line of sight angle error constraint value respectively.

6. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 1, characterized in that: The semi-analytical algorithm based on obstacle avoidance constraints is specifically: improving the lateral planning part of the near-analytical gliding trajectory planning method considering the full-state constraints of time and space, selecting one of the trajectories as the trajectory to be adjusted, and avoiding collision by adjusting the last roll reversal timing before the collision point, including: The flight trajectory between the collision point and the previous bank reversal position is defined as the collision avoidance adjustment segment; By analyzing the collision process of the aircraft and the characteristics of the collision avoidance adjustment section, the collision avoidance adjustment section range S is selected. c ,average height Average speed Average roll angle amplitude Minimum safety distance p safe and reversal timing adjustment is the key parameter; Traverse S c , and As a simulation condition, the position change Δp of the adjusted trajectory at the original collision point energy is obtained by trajectory simulation method; The input for the build is S c , p safe and The output is interpolation table; finally, when trajectory adjustment is required, enter S c , p safe and Find and output the values ​​that satisfy Δp≥p safe Requested The reversal timing adjustment amount that satisfies the collision avoidance constraint can be obtained.

7. The method for rapid reentry trajectory planning of multiple gliding aircraft coordinated formation according to claim 1, characterized in that: The trajectory of the leader is planned based on a semi-analytical algorithm that considers obstacle avoidance constraints, without considering terminal time and heading angle constraints.

8. A multi-gliding aircraft coordinated formation re-entry trajectory rapid planning system, characterized in that: It includes the rendezvous and assembly phase planning module and the formation-keeping phase trajectory planning module; The intersection and assembly segment trajectory planning module adopts a coordination-execution double-layer architecture for trajectory planning; Among them, the coordination layer includes a spatiotemporal capability boundary prediction submodule and a coordination information adaptive solution submodule; the spatiotemporal capability boundary prediction submodule is used to predict the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point based on the spatiotemporal capability boundary prediction method; the coordination information adaptive solution submodule is used to determine the real assembly point constraints of each aircraft according to the arrival time, heading angle, position and formation configuration of each aircraft's virtual assembly point; based on the coordination information and the arrival time, heading angle and position adjustable range of each aircraft's virtual assembly point, the constraint value of each aircraft's real assembly point is adaptively solved; the execution layer includes an assembly trajectory planning submodule, which is used to use the real assembly point constraint value of each aircraft as the terminal constraint, and plan the rendezvous and assembly segment trajectory of each aircraft based on a semi-analytical algorithm considering obstacle avoidance constraints; The formation holding segment trajectory planning module adopts a leader-follower collaborative architecture for trajectory planning; Among them, the leader includes a leader trajectory planning submodule, which is used to plan the trajectory of the leader based on a semi-analytical algorithm that considers obstacle avoidance constraints; the follower layer includes a follower trajectory planning submodule, which is used to generate formation instructions based on the altitude and heading angle of the neighboring communicative aircraft through a progressive consistency control algorithm, and realize the formation holding segment trajectory planning based on the formation instructions.

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