Aircraft over-the-horizon efficient maneuvering energy planning method based on control parameterization

Abstract

The invention discloses an aircraft over-the-horizon efficient maneuvering energy planning method based on control parameterization, and mainly solves the problems that an existing planning algorithm is poor in universality and cannot guarantee real-time performance under the airborne condition. According to the method, firstly, modeling is carried out on energy changes in the maneuvering process of the aircraft, energy currently owned by the aircraft is calculated, then the current maximum available overload of the aircraft is predicted, then the energy machine process carried out when the aircraft reaches a target instruction is established as an optimization problem, and then solving is carried out. And finally, a control parameterization method is used for solving, and the energy maneuvering process of the aircraft is obtained online. Compared with other algorithms based on model prediction, the method provided by the invention is shorter in solving time and has better real-time performance in airborne application.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft energy planning, and in particular, relates to an aircraft beyond-visual-range efficient maneuvering energy planning method based on control parameterization. Background Art

[0002] With the rapid development of modern weapons and radar technology, the battles between fighters have long been separated from the previous methods of relying on visual aiming and cannon shooting. Beyond visual range air combat has become the main scene of modern air combat. In the process of beyond visual range air combat, the fighter mainly uses its own maneuvers to put itself in an advantageous position, while avoiding the enemy's missile attack, it launches missiles to shoot down the enemy. Therefore, the final victory or defeat of the air combat mainly depends on the reconnaissance capabilities, weapon strike capabilities and its own maneuverability of both sides. When the aircraft accelerates, decelerates, climbs, descends, hovers, etc. during the maneuvering process, it will be accompanied by changes in energy and overload. In modern air combat, the reconnaissance and strike capabilities of both sides are often similar, so being able to efficiently plan the maneuvering energy can maximize the advantage in air combat.

[0003] Domestic and foreign research on beyond-visual-range air combat maneuver energy planning mainly focuses on the analysis of longitudinal flight trajectories, and is based on the current state. There are the following problems: (1) Only the longitudinal trajectory of the aircraft is analyzed, which cannot be applied in all scenarios. (2) The energy planning of the aircraft to achieve the target state can only be simply set, and it is impossible to achieve multiple states at the same time. (3) In the process of aircraft maneuver energy decision-making, the aircraft state is not updated, so there is a certain difference between the result and the expectation. (4) Traditional model prediction algorithms require a lot of computing resources and cannot guarantee the real-time and precision of the calculation under airborne conditions.

[0004] The above methods have the following technical problems: (1) the planning algorithm has poor versatility; (2) real-time performance cannot be guaranteed in airborne conditions. Summary of the invention

[0005] The purpose of the present invention is to provide a method for planning the energy of an aircraft beyond visual range efficient maneuver based on control parameterization, which mainly solves the problems that the existing planning algorithms have poor versatility and cannot guarantee real-time performance under airborne conditions.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization comprises the following steps:

[0008] S1, establish the three-degree-of-freedom dynamic equation of the aircraft's angle of attack and calculate the aircraft's overload;

[0009] S2, establish an energy model for the aircraft's maneuvering process and calculate the current energy of the aircraft;

[0010] S3, calculating the upper and lower limits of the available overload of the aircraft based on the current total available energy of the aircraft;

[0011] S4, establishing an objective function of the interception time that satisfies the aircraft kinematic model;

[0012] S5, using the performance constraints of the aircraft and the load factor of the aircraft as the constraints of the objective function, establish the optimal control problem of beyond visual range air combat maneuver energy planning;

[0013] S6, using the control parameter method to solve the optimal control problem, and finally outputting the control sequence for the aircraft to intercept the target speed command, so as to achieve the fastest speed and meet the optimal maneuver of intercepting the command without consuming more energy than the total energy of the aircraft.

[0014] Furthermore, in step S1, the three-degree-of-freedom dynamic equation is:

[0015]

[0016] x(t)=[x(t), y(t), z(t), V(t), γ(t), χ(t)] T

[0017] u(t)=[T(t),α(t),μ(t)] T

[0018] In the formula, the state quantity x is the position coordinate (x, y, z), the climb angle γ, the yaw angle χ, and the speed V, and the control quantity u is the aircraft thrust T, the aircraft angle of attack α and the roll angle μ; D is the resistance during the flight, W is the total weight of the aircraft, and g is the gravitational acceleration; then the overload of the aircraft is:

[0019]

[0020] Where n x is the tangential overload of the aircraft, that is, the overload pointing in the direction of flight, n n It is normal overload, and its direction is perpendicular to the flight direction.

[0021] Furthermore, in step S2, the energy model of the maneuvering process is:

[0022]

[0023] In the formula, E T is the total energy of the aircraft, which is composed of the kinetic energy and potential energy of the aircraft; E D is the kinetic energy of the aircraft, E Sis the potential energy of the aircraft; m is the mass of the aircraft, g is the acceleration due to gravity, and z is the flight altitude of the aircraft.

[0024] Furthermore, in step S4, the objective function is:

[0025]

[0026] where t f is the terminal time, that is, the optimization goal can be described as reaching the target in the shortest time.

[0027] Furthermore, the optimal control problem obtained in step S5 is:

[0028]

[0029]

[0030] x(0)=x0

[0031] u(t)=[T(t),α(t),μ(t)] T

[0032]

[0033]

[0034]

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The present invention considers both longitudinal and lateral maneuvers of the aircraft and analyzes the entire energy planning process. The aircraft status can be updated along with the planning process. Compared with other algorithms based on model prediction, the present invention has a shorter solution time and better real-time performance for airborne applications.

[0037] (2) The present invention can carry out diversified designs of aircraft terminal interception instructions, which is applicable to more scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a principle block diagram of the present invention.

[0039] Figure 2 This is the fastest speed interception target speed curve diagram in the embodiment of the present invention.

[0040] Figure 3 This is a graph showing the minimum energy capture target speed in an embodiment of the present invention.

[0041] Figure 4 This is a graph of the target height captured at the fastest speed in an embodiment of the present invention.

[0042] Figure 5 This is a graph showing the minimum energy target height interception in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The embodiments of the present invention include but are not limited to the following embodiments.

[0044] like Figure 1 As shown, the invention discloses a method for efficient energy planning of over-the-horizon maneuvering of an aircraft based on control parameterization. It first considers modeling the energy change of the aircraft maneuvering process, calculating the current energy of the aircraft, and then predicting the current maximum available overload of the aircraft. Then, the energy machine process for the aircraft to reach the target instruction is established as an optimization problem, and then solved. Finally, the control parameterization method is used to solve the problem, and the aircraft energy maneuvering process is obtained online.

[0045] The present invention uses a nonlinear predictive control method to optimize the energy during the maneuvering process of the aircraft. The three-degree-of-freedom dynamic equation considering the angle of attack of the aircraft is as follows:

[0046]

[0047] x(t)=[x(t), y(t), z(t), V(t), γ(t), χ(t)] T

[0048] u(t)=[T(t),α(t),μ(t)] T

[0049] Wherein, the state quantity x is the position coordinate (x, y, z), the climb angle γ, the yaw angle χ, and the speed V, and the control quantity u is the aircraft thrust T, the aircraft angle of attack α, and the roll angle μ; L is the aircraft lift, D is the resistance during flight, W is the total weight of the aircraft, and g is the acceleration of gravity;

[0050]

[0051] where n x is the tangential overload of the aircraft, that is, the overload pointing in the direction of flight, n n It is normal overload, and its direction is perpendicular to the flight direction.

[0052] After establishing the dynamic equation, the energy model of the aircraft maneuvering process is established. According to the analysis of energy changes during the flight of the aircraft, the total energy can be expressed as:

[0053]

[0054] In the formula, ET is the total energy of the aircraft, which is composed of the kinetic energy and potential energy of the aircraft; E D is the kinetic energy of the aircraft, E S is the potential energy of the aircraft; m is the mass of the aircraft, g is the acceleration due to gravity, and z is the flight altitude of the aircraft.

[0055] Assuming that the initial thrust of the aircraft offsets the aircraft drag during level flight, and the drag on the aircraft does not change when the flight state changes, the thrust and flight state increment equations can be expressed as:

[0056]

[0057] The thrust change of the aircraft is proportional to the rate of change of the unit aircraft energy. In the analysis, it is approximately assumed that the deflection of the aircraft's elevator and rudder does not change the total energy of the aircraft, indicating that the kinetic energy and potential energy of the aircraft can be converted into each other by manipulating the rudder deflection without significant energy loss. Therefore, the upper and lower limits of the aircraft's available overload can be calculated based on the current total available energy of the aircraft, providing a basis for the subsequent planning algorithm.

[0058] For example, when the interception target is a speed command, the total energy currently available is calculated based on our state, the target is set to intercept the target speed command at the fastest speed, and the target function is established based on the interception time:

[0059]

[0060] where t f is the terminal time, that is, the optimization goal can be described as reaching the target in the shortest time.

[0061] The objective function satisfies the vehicle kinematic model:

[0062]

[0063] x(0)=x0

[0064] Considering the performance constraints of the aircraft, the value range of the aircraft load factor should meet the following requirements:

[0065] T min ≤T(t)≤T max

[0066] α min ≤α(t)≤α max

[0067] μ min ≤μ(t)≤μ max

[0068] E(t)≤E Tmax

[0069] V min ≤V(t)≤V max

[0070] χ min ≤χ(t)≤χ max

[0071] γ min ≤γ(t)≤γ max

[0072] Among them, E Tmax The upper and lower limits of the control quantity [T, α, μ] are determined by the performance of the aircraft itself, and the upper and lower limits of the state quantity are determined by the performance of the aircraft itself and the specific scenario.

[0073] The optimal control problem of beyond visual range air combat maneuver energy planning is: under the constraint of the system dynamic equation:

[0074]

[0075] x(0)=x0

[0076] And the performance inequality constraints:

[0077] T min ≤T(t)≤T max

[0078] α min ≤α(t)≤α max

[0079] μ min ≤μ(t)≤μ max

[0080] E(t)≤E Tmax

[0081] V min ≤V(t)≤V max

[0082] χ min ≤χ(t)≤χ max

[0083] γ min ≤γ(t)≤γ max

[0084] At the same time, the constraints such as radar frame angle are considered to minimize the above objective function, and the interception target instruction is set as the terminal constraint. For different scenarios, the threshold and constraint form in the performance inequality constraint are different.

[0085] For the above energy planning optimal control problem, the control parameter method is used to solve it, and finally the aircraft control sequence for intercepting the target speed command is output, which achieves the fastest speed and satisfies the optimal maneuver of intercepting the command without consuming more energy than the total energy of the aircraft.

[0086] The above-mentioned continuous-time aircraft particle model can be regarded as a discrete system within a short step size, and the continuous system can be approximated by a discrete difference system. The time periods are equally discretized, and the continuous-time maneuvering decision control quantity is approximated by parameter discretization. When the optimization time domain is short, the tracking control hysteresis and calculation time of the underlying controller can be further optimized.

[0087] Taking actual operation as an example, the intercepted target speed is analyzed, and the specific values ​​of various performance parameters and optimization problem parameters in the simulation are shown in Table 1. The simulation environment is Matlab2019a, and Fmincon is used to solve the optimization problem.

[0088] Table 1 Aircraft maneuverability parameters and optimization problem parameters

[0089]

[0090]

[0091] Consider that the aircraft reaches a given height and speed, and intercepts the given command as quickly as possible and with the least energy consumption. Set the initial state of the aircraft to:

[0092] [x, y, z, V, χ, γ] T =[30000, 0, 5000, 160, π, 0] T

[0093] Set the target height to h tf =6500m, set the target speed to V tf =200m / s, by Figures 2 to 5 It can be seen that when the aircraft wants to reach the target speed as quickly as possible, it needs a larger thrust to accelerate. If it wants to consume less energy to reach the target speed, it chooses to trade altitude for speed and dives down. The situation of reaching the target altitude is similar. The energy consumed by the aircraft to reach the target command and the time are shown in Table 2.

[0094] Table 2. Results of energy maneuvers for aircraft in BVR air combat

[0095]

[0096] Through the above design, the present invention simultaneously considers the longitudinal and lateral maneuvers of the aircraft, and analyzes the entire energy planning process. The aircraft status can be updated along with the planning process. Compared with other algorithms based on model prediction, the present invention has a shorter solution time and better real-time performance in airborne applications.

[0097] The above embodiment is only one of the preferred implementation modes of the present invention and should not be used to limit the protection scope of the present invention. Any changes or modifications that are made to the main design concept and spirit of the present invention and have no substantive significance, and the technical problems they solve are still consistent with the present invention, should be included in the protection scope of the present invention.

Claims

1. A method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization, characterized in that: The steps include: S1, establish the three-degree-of-freedom dynamic equation of the aircraft's angle of attack and calculate the aircraft's overload; S2, establish an energy model for the aircraft's maneuvering process and calculate the current energy of the aircraft; S3, calculating the upper and lower limits of the available overload of the aircraft based on the current total available energy of the aircraft; S4, establishing an objective function of the interception time that satisfies the aircraft kinematic model; S5, using the performance constraints of the aircraft and the load factor of the aircraft as the constraints of the objective function, establish the optimal control problem of beyond visual range air combat maneuver energy planning; S6, using the control parameter method to solve the optimal control problem, and finally outputting the control sequence for the aircraft to intercept the target speed command, so as to achieve the fastest speed and meet the optimal maneuver of intercepting the command without consuming more energy than the total energy of the aircraft.

2. The method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization according to claim 1, characterized in that: In step S1, the three-degree-of-freedom dynamic equation is: x(t)=[x(t),y(t),z(t),V(t),γ(t),χ(t)] T u(t)=[T(t),α(t),μ(t)] T In the formula, the state quantity x is the position coordinate (x, y, z), the climb angle γ, the yaw angle χ, and the speed V, and the control quantity u is the aircraft thrust T, the aircraft angle of attack α and the roll angle μ; L is the aircraft lift, D is the resistance during flight, W is the total weight of the aircraft, and g is the acceleration of gravity; then the overload of the aircraft is: where n x is the tangential overload of the aircraft, that is, the overload pointing in the direction of flight, n n It is normal overload, and its direction is perpendicular to the flight direction.

3. The method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization according to claim 2 is characterized in that: In step S2, the energy model of the maneuvering process is: In the formula, E T is the total energy of the aircraft, which is composed of the kinetic energy and potential energy of the aircraft; E D is the kinetic energy of the aircraft, E S is the potential energy of the aircraft; m is the mass of the aircraft, g is the acceleration due to gravity, and z is the flight altitude of the aircraft.

4. The method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization according to claim 3 is characterized in that: In step S4, the objective function is: where t f To optimize the terminal time of the problem, the goal is to consume the least time to achieve the goal.

5. The method for efficient beyond visual range maneuvering energy planning of an aircraft based on control parameterization according to claim 4 is characterized in that: The optimal control problem obtained in step S5 is: stx(t)=f(x(t),u(t)) x(0)=x0 u(t)=[T(t),α(t),μ(t)] T

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