A pre-allocated target artificial potential field based aircraft cluster collision avoidance method

Abstract

The application discloses a pre-allocated target artificial potential field-based aircraft cluster collision avoidance method, which quantifies the influence range and degree of the rear aircraft flight stability caused by the front aircraft wake vortex, instead of simply taking physical collision as a safety standard, so as to provide an accurate theoretical basis for safety avoidance; the method adopts a segmented improved artificial potential field to generate an avoidance acceleration instruction acting only in the normal direction, strictly prohibits the aircraft from entering the wake vortex danger area, and guarantees the real-time performance and engineering realizability of the instruction; the method also takes the consistency error of the aircraft estimated attack time as a coordination variable, and makes all the aircrafts reach the target at the same time within a limited time. One of the core purposes of the method is to organically integrate the above-mentioned collision avoidance and control scheme to form a unified guidance framework. The method can simultaneously process two key tasks of flight safety and time efficiency, and ensures that the cooperative task can be efficiently and reliably completed under the complex aerodynamic coupling environment.

Description

Technical Field

[0001] This invention relates to the field of swarm control technology for aircraft formations, and specifically to a method for collision avoidance in aircraft swarms based on pre-assigned targets and artificial potential fields. Background Technology

[0002] With the rapid development of UAV and other aircraft technologies, multi-aircraft swarm collaborative mission execution has become an important development direction in the future aviation field. Aircraft swarms have demonstrated significant advantages in scenarios such as dense formation flight, collaborative reconnaissance, area coverage, and material delivery. To achieve high-precision collaborative operations, each UAV in the swarm needs to maintain a precise relative position and stable flight attitude. Currently, mainstream aircraft collaborative guidance methods are mostly based on consensus theory, model predictive control, or artificial potential field methods. These methods typically treat each aircraft as an independent point mass or rigid body, mainly considering its own dynamics and kinematic constraints, and exchanging state information through inter-aircraft communication to achieve collaborative path tracking and formation maintenance.

[0003] However, these methods generally overlook the complex aerodynamic interactions that occur when aircraft swarms fly at close range. During dense flight, the presence of wing wake vortices causes the dynamic characteristics of aircraft within the swarm to be coupled with the wake vortex flow fields of neighboring aircraft, leading to flight safety issues. Therefore, coordinated strikes by aircraft swarms not only require studying spatiotemporally consistent coordinated guidance but also must consider the flight safety problems caused by wake vortices, making it uniquely complex.

[0004] Existing collaborative guidance methods for aircraft lack the ability to model and deeply integrate the wake vortex interference effect within the swarm into the guidance law design, making it difficult to meet the practical requirements of high-density, high-precision, and high-reliability collaborative flight of aircraft swarms. This has become a key technical bottleneck restricting the development of advanced aircraft swarm technology.

[0005] Based on the above problems, the inventors have conducted in-depth research on multi-aircraft swarm collision avoidance methods in order to design an aircraft swarm collision avoidance method with low computational cost and real-time output results. Summary of the Invention

[0006] To overcome the aforementioned problems, the inventors conducted in-depth research and designed a pre-assigned target collision avoidance method for aircraft swarms based on an artificial potential field. This method quantifies the range and degree of influence of the wake vortex of the preceding aircraft on the flight stability of the following aircraft, rather than simply using physical collision as the safety standard, thus providing a precise theoretical basis for safe avoidance. The method employs a segmented improved artificial potential field to generate avoidance acceleration commands that act only in the normal direction, strictly prohibiting aircraft from entering the wake vortex danger zone, while ensuring the real-time nature and engineering feasibility of the commands. The method also uses the consistency error of the aircraft's estimated attack time as a coordination variable to enable all aircraft to reach the target simultaneously within a finite time. One of the core objectives of this method is to organically integrate the above-mentioned collision avoidance and control schemes to form a unified guidance framework. This framework can simultaneously handle the two key tasks of flight safety and arrival timeliness, ensuring that the aircraft swarm can still efficiently and reliably complete collaborative tasks in complex aerodynamic coupling environments, thus completing this invention.

[0007] Specifically, the purpose of this invention is to provide a method for collision avoidance of aircraft swarms based on pre-assigned targets and artificial potential fields. In the process of each aircraft in the aircraft swarm flying independently toward its target, each aircraft performs the following steps. Step 1: The aircraft receives the position, speed and remaining flight time information of neighboring aircraft in real time, and at the same time transmits its own position, speed and remaining flight time information to the neighboring aircraft. Step 2: Generate normal guidance acceleration commands based on proportional guidance method to control the aircraft to fly toward the target; Step 3: Based on the relative position with the nearby aircraft in front, use an artificial potential field to generate a normal avoidance acceleration command to avoid the wake vortex interference of the aircraft in front. Step 4: Based on the received remaining flight time information of neighboring aircraft, generate axial acceleration commands to eliminate arrival time errors of individual aircraft in the cluster. Step 5: Combine the total normal acceleration command and the axial acceleration command to form a total control command, and control the aircraft to fly toward the target through the aircraft's control system.

[0008] In step 2, the first Normal guidance acceleration command for the aircraft Obtained through the following formula (i): (one) in, Indicates the proportional guidance coefficient; Indicates the first The speed of the aircraft; Indicates the first The line-of-sight angular velocity between the aircraft and its target.

[0009] In step 3, when the following aircraft is in the wake warning zone of the preceding aircraft, the normal avoidance acceleration command is obtained by the following formula (ii): (two); When the following aircraft is in the strictly restricted area of ​​the preceding aircraft, the normal avoidance acceleration command is given by the following equation (iii): (three); in, and Each represents a segmentation ratio coefficient independently; A coefficient representing the magnitude of the further constraint repulsive force; Indicates the first The speed of the aircraft; It indicates the distance between the following aircraft and the preceding aircraft.

[0010] The wake vortex warning region and the strictly restricted region are obtained through the following sub-steps: Sub-step 1: Based on the mass, speed and wingspan parameters of the forward-facing aircraft, obtain the initial circulation of its wake vortex; Sub-step 2: Using the Hallock-Burnham vortex model, based on the position of the vortex core and the real-time circulation intensity, the vertical induced velocity generated by any point in the wake vortex field on the aircraft behind is obtained. This vertical induced velocity is integrated along the wingspan of the aircraft behind to obtain the induced roll moment coefficient generated by the aerodynamic coupling effect. Based on the moment balance relationship, the equivalent induced roll angular velocity required to counteract this moment is derived. Sub-step 3: Retrieve the maximum induced roll angular velocity threshold that the flight control system of the aircraft can stably withstand. The equivalent induced roll angular velocity value is 0.3. -0.5 The spatial region is defined as the wake vortex warning region, with the equivalent induced roll velocity value set at 0.5. -0.8 The spatial region is defined as a strictly restricted region.

[0011] In step 4, the first The axial acceleration command on the aircraft is obtained by the following formula (iv): (Four) in, Indicates the first Consistency error in estimated arrival time of individual aircraft within the cluster; This represents the coefficient used to adjust the axial acceleration of the aircraft; its value is 0.5. This represents the proportional coefficient of the coordinated guidance law within a finite time, and its value is 0.8.

[0012] Among them, the first Consistency error in estimated arrival time of individual aircraft within the cluster Obtained through the following formula (5): (five) in, Represents the first in the cluster One aircraft, This indicates the total number of aircraft in the cluster; Indicates the first The aircraft and the first The communication relationship between the aircraft, when the first The aircraft and the first When individual aircraft can communicate and exchange information The value is 1 if it is set to 1, otherwise the value is 0. Indicates the first The estimated arrival time of each aircraft; Indicates the first The estimated arrival time of an aircraft is obtained based on the remaining flight time.

[0013] Among them, the Remaining flight time for each aircraft Obtained through the following formula (VI): (six) in, Indicates the first The relative distance between an aircraft and its target; express The derivative of, i.e., the first The relative speed between the aircraft and its target.

[0014] In step 5, the first The total normal acceleration command for the aircraft Obtained through the following formula (vii); (seven).

[0015] Among them, when ,and At that time, or when ,and hour, ; when ,and At that time, or when ,and hour, ; in, Indicates the first The heading angle of the aircraft.

[0016] The beneficial effects of this invention include: (1) According to the pre-allocated target-based artificial potential field collision avoidance method of the aircraft swarm provided by the present invention, the method introduces a dynamic danger zone model with induced roll angular velocity as the core criterion, which changes the limitation of the traditional method that only considers physical collision. This enables the aircraft to perceive and quantify the instability threat caused by aerodynamic disturbance in advance, so as to be more forward-looking and scientific when performing evasive maneuvers, and fundamentally avoid roll loss of control caused by entering the strong wake vortex region.

[0017] (2) According to the pre-allocated target-based artificial potential field collision avoidance method of the aircraft swarm provided by the present invention, the method ensures that evasion maneuvers and cooperative guidance are no longer conflicting tasks through the integrated design of the fusion control law; even when evasion maneuvers are continuously performed, the swarm can ensure that all aircraft achieve simultaneous attack within a limited time through the distributed cooperative algorithm, thus solving the traditional problem of "sacrificing cooperative accuracy for safety".

[0018] (3) According to the pre-assigned target-based artificial potential field collision avoidance method for aircraft swarms provided by the present invention, the proposed normal-only avoidance strategy does not require the aircraft to provide large axial overloads that are difficult to achieve, which greatly reduces the burden on the propulsion system and is more in line with actual engineering constraints. The improved artificial potential field method is simple to calculate and responds quickly, which can meet the stringent requirements for real-time online calculation during dense formation flight.

[0019] (4) According to the pre-assigned target-based collision avoidance method for aircraft swarms provided by the present invention, the method provides a complete perception-decision-control framework, rather than a fixed trajectory planning; therefore, it can adapt to the dynamic changes in formation, the switching of communication topology and the movement of targets during the flight of aircraft swarms, and other uncertainties, and exhibits strong robustness. Attached Figure Description

[0020] Figure 1This paper presents an overall logic diagram of the aircraft swarm collision avoidance method based on an artificial potential field for pre-assigned targets. Figure 2 This application illustrates a communication topology diagram in an embodiment of the invention. Figure 3 This diagram illustrates the flight trajectories of 10 aircraft in the embodiment. Figure 4 The curve showing the change in the axial acceleration of the aircraft is shown. Figure 5 This diagram illustrates the variation of normal avoidance acceleration over time on some aircraft in the embodiment, generated to avoid the dangerous area of ​​the wake vortex. Figure 6 A schematic diagram showing how the remaining flight time of the aircraft changes over time; Figure 7 The relative positions of the second aircraft in the wake vortex warning zone, strictly restricted zone, and danger zone generated by the third aircraft are shown in the embodiment. Figure 8 The diagram shows the relative positions of the 8th aircraft in the wake vortex warning zone, strictly restricted zone, and danger zone generated by the 9th aircraft in the embodiment. Figure 9 The diagram shows the roll angular velocity curves of each aircraft within the cluster affected by the wake vortices of other aircraft when the method of this application is used. Figure 10 The diagram shows the roll velocity curves of each aircraft in the cluster affected by the wake vortices of other aircraft when no wake vortex avoidance is performed, as shown in the comparative example. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present invention will become clearer and more apparent.

[0022] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0023] According to the present invention, a pre-assigned target-based collision avoidance method for aircraft swarms based on artificial potential fields is provided. During the process of each aircraft in the aircraft swarm flying independently toward its target, each aircraft performs the following steps. Step 1: The aircraft receives the position, speed and remaining flight time information of neighboring aircraft in real time, and at the same time transmits its own position, speed and remaining flight time information to the neighboring aircraft. In this application, the selection range of neighboring aircraft is determined based on factors such as the model and power of the equipment used to transmit signals on the aircraft. Each aircraft corresponds to at least one neighboring aircraft, and by setting this selection range, it is ensured that for any aircraft, the aircraft that its own wake vortex can interfere with are its neighboring aircraft.

[0024] Step 2: Generate normal guidance acceleration commands based on proportional guidance method to control the aircraft to fly toward the target; Preferably, in step 2, the first Normal guidance acceleration command for the aircraft Obtained through the following formula (i): (one) in, This represents the proportional guidance coefficient, with a value of 4. Indicates the first The speed of an aircraft can be obtained through a satellite receiver or an inertial navigation system. Indicates the first The line-of-sight angular velocity between an aircraft and its target is obtained in real time by sensors on the aircraft.

[0025] Step 3: Based on the relative position with the nearby aircraft in front, use an artificial potential field to generate a normal avoidance acceleration command to avoid the wake vortex interference of the aircraft in front. Preferably, in step 3, when the following aircraft is in the wake warning zone of the preceding aircraft, the normal avoidance acceleration command is:

[0026] When the following aircraft is within the strictly restricted area of ​​the preceding aircraft, the normal evasion acceleration command is:

[0027] in, and Each represents a segmentation ratio coefficient independently; A coefficient representing the magnitude of the further constraint repulsive force is preferably taken as a value of ; Indicates the first The speed of the aircraft; It indicates the distance between the following aircraft and the preceding aircraft.

[0028] Preferably, when ,and At that time, or when ,and hour, ; when ,and At that time, or when ,and hour, ; Indicates the first The line-of-sight angle between the aircraft and the target is obtained in real time through the seeker. in, Indicates the first The heading angle of each aircraft is measured in real time using a magnetic compass on the aircraft.

[0029] Preferably, the wake vortex warning region and the strictly restricted region are obtained through the following sub-steps: Sub-step 1: Based on the mass, speed and wingspan parameters of the forward-facing aircraft, obtain the initial circulation of its wake vortex; Sub-step 2: Using the Hallock-Burnham vortex model, based on the position of the vortex core and the real-time circulation intensity, the vertical induced velocity generated by any point in the wake vortex field on the aircraft behind is obtained. This vertical induced velocity is integrated along the wingspan of the aircraft behind to obtain the induced roll moment coefficient generated by the aerodynamic coupling effect. Based on the moment balance relationship, the equivalent induced roll angular velocity required to counteract this moment is derived. Sub-step 3: Retrieve the maximum induced roll angular velocity threshold that the flight control system of the aircraft can stably withstand. The equivalent induced roll angular velocity value is 0.3. -0.5 The spatial region is defined as the wake vortex warning region, in which the artificial potential field begins to take effect; the equivalent induced roll angular velocity value is set at 0.5. -0.8 The spatial region is defined as a strictly confined region where an artificial potential field provides a large force; the equivalent induced roll angular velocity exceeds 0.8. The spatial region is defined as the wake vortex hazard zone. In principle, the UAV following behind should not enter this hazard zone. If it does enter, it must provide maximum normal avoidance acceleration to escape as quickly as possible. During testing, simulation, and actual controlled flight, no UAVs have entered this hazard zone, indicating that the establishment of the aforementioned warning zone and strictly restricted zone eliminates the possibility of a following aircraft entering the hazard zone. In this application, the wake vortex hazard zone is included within the strictly restricted zone, and the strictly restricted zone is included within the wake vortex warning zone. These zones are spatially shaped as approximate strips, longer longitudinally and narrower laterally, centered on the preceding UAV.

[0030] Step 4: Based on the received remaining flight time information of neighboring aircraft, generate axial acceleration commands to eliminate arrival time errors of individual aircraft in the cluster. Preferably, in step 4, the first The axial acceleration command on the aircraft is obtained by the following formula (iv): (Four) in, Indicates the first Consistency error in estimated arrival time of individual aircraft within the cluster; This represents the coefficient used to adjust the axial acceleration of the aircraft; its value is 0.5. This represents the proportional coefficient of the coordinated guidance law within a finite time, and its value is 0.8.

[0031] In this application, the flight speed is adjusted by the aforementioned axial acceleration command, thereby adjusting the arrival time and ensuring finite-time convergence. Based on Lyapunov stability theory, the inventors constructed a Lyapunov function and verified that under the guidance law, the system's consistency error can converge to zero within a finite time, i.e., achieving consistency in arrival time.

[0032] Preferably, the first Consistency error in estimated arrival time of individual aircraft within the cluster Obtained through the following formula (5): (five) in, Represents the first in the cluster One aircraft, This indicates the total number of aircraft in the cluster; Indicates the first The aircraft and the first The communication relationship between the aircraft, when the first The aircraft and the first When individual aircraft can communicate and exchange information The value is 1 if it is set to 1, otherwise the value is 0. Indicates the first The estimated arrival time of each aircraft; Indicates the first The estimated arrival time of an aircraft is obtained based on the remaining flight time, which is obtained by adding the remaining flight time to the current time.

[0033] Preferably, the first Remaining flight time for each aircraft Obtained through the following formula (VI): (six) in, Indicates the first The relative distance between an aircraft and its target; express The derivative of, i.e., the first The relative speed between the aircraft and its target.

[0034] Step 5: Combine the total normal acceleration command and the axial acceleration command to form a total control command, and control the aircraft to fly toward the target through the aircraft's control system.

[0035] Preferably, in step 5, the first The total normal acceleration command for the aircraft Obtained through the following formula (vii); (seven). Example

[0036] In the square area km, There are 10 aircraft on a surface of km, each with an initial position fixed within a square area. km, There are 10 targets at a distance of km. The aircraft's flight speed is set to... The mission involves 10 aircraft simultaneously reaching 10 target locations within an area. Each aircraft... All according to Figure 2 The communication topology shown enables communication with other aircraft.

[0037] The control methods on the aircraft are as follows: Step 1: The aircraft receives the position, speed and remaining flight time information of neighboring aircraft in real time, and at the same time transmits its own position, speed and remaining flight time information to the neighboring aircraft. Step 2: Generate normal guidance acceleration commands based on proportional guidance method to control the aircraft to fly toward the target; No. Normal guidance acceleration command for the aircraft Obtained through the following formula (i): (one) in, This represents the proportional guidance coefficient, with a value of 4. Indicates the first The speed of the aircraft; Indicates the first The line-of-sight angular velocity between the aircraft and its target.

[0038] Step 3: Based on the relative position with the nearby aircraft in front, use an artificial potential field to generate a normal avoidance acceleration command to avoid the wake vortex interference of the aircraft in front. In step 3, when the following aircraft is within the wake vortex warning zone of the preceding aircraft, the normal avoidance acceleration command is:

[0039] When the following aircraft is within the strictly restricted area of ​​the preceding aircraft, the normal evasion acceleration command is: .

[0040] in, and Each represents a segmentation ratio coefficient independently; when ,and At that time, or when ,and hour, ; when ,and At that time, or when ,and hour, ; A coefficient representing the magnitude of the further constraint repulsive force, with a value of 30; Indicates the first The speed of the aircraft; This indicates the distance between the following and preceding aircraft. The wake vortex warning zone and the strictly restricted zone are obtained through the following sub-steps: Sub-step 1: Based on the mass, speed and wingspan parameters of the forward-facing aircraft, obtain the initial circulation of its wake vortex; Sub-step 2: Using the Hallock-Burnham vortex model, based on the position of the vortex core and the real-time circulation intensity, the vertical induced velocity generated by any point in the wake vortex field on the aircraft behind is obtained. This vertical induced velocity is integrated along the wingspan of the aircraft behind to obtain the induced roll moment coefficient generated by the aerodynamic coupling effect. Based on the moment balance relationship, the equivalent induced roll angular velocity required to counteract this moment is derived. Sub-step 3: Retrieve the maximum induced roll angular velocity threshold that the flight control system of the aircraft can stably withstand. The equivalent induced roll angular velocity value is 0.3. -0.5 The spatial region is defined as the wake vortex warning region; the equivalent induced roll velocity value is set at 0.5. -0.8 The spatial region is defined as a strictly restricted region.

[0041] Step 4: Based on the received remaining flight time information of neighboring aircraft, generate axial acceleration commands to eliminate arrival time errors of individual aircraft in the cluster. In step 4, the first The axial acceleration command on the aircraft is obtained by the following formula (iv): (Four) in, Indicates the first Consistency error in estimated arrival time of individual aircraft within the cluster; This represents the coefficient used to adjust the axial acceleration of the aircraft; its value is 0.5. This represents the proportional coefficient of the coordinated guidance law within a finite time, and its value is 0.8.

[0042] The first Consistency error in estimated arrival time of individual aircraft within the cluster Obtained through the following formula (5): (five) in, Represents the first in the cluster One aircraft, This indicates the total number of aircraft in the cluster; Indicates the first The aircraft and the first The communication relationship between the aircraft, when the first The aircraft and the first When individual aircraft can communicate and exchange information The value is 1 if it is set to 1, otherwise the value is 0. Indicates the first The estimated arrival time of each aircraft; Indicates the first The estimated arrival time of an aircraft is obtained based on the remaining flight time.

[0043] No. Remaining flight time for each aircraft Obtained through the following formula (VI): (six) in, Indicates the first The relative distance between an aircraft and its target; Indicates the first The relative speed between the aircraft and its target.

[0044] Step 5: Combine the total normal acceleration command and the axial acceleration command to form a total control command, and control the aircraft to fly toward the target through the aircraft's control system.

[0045] Among them, the The total normal acceleration command for the aircraft Obtained through the following formula (vii); (seven).

[0046] Specific simulation results are as follows: Figures 3 to 8 As shown; Figure 3 The flight trajectories of 10 aircraft are shown in the figure. It can be seen from the figure that by using the control scheme of this application, multiple aircraft in the cluster can reach the target position.

[0047] Figure 4 The figure shows the axial acceleration variation curve of the aircraft; it can be seen from the figure that the present application scheme achieves the effect of simultaneously reaching the target position by adjusting the axial acceleration of the aircraft to match the normal acceleration variation.

[0048] Figure 5 The diagram shows the variation of normal evasion acceleration generated on a partial aircraft over time to avoid the dangerous area of ​​the wake vortex. The diagram shows that the proposed solution will perform necessary normal evasion maneuvers to ensure flight safety.

[0049] Figure 6 The diagram shows the remaining flight time of the aircraft as a function of time. It can be seen from the diagram that the proposed solution provides a good guarantee for the consistency of cooperative arrival time.

[0050] Figure 7 The diagram shows the relative positions of the second aircraft near the wake vortex warning area, the strictly restricted area, and the danger zone generated by the third aircraft. As can be seen from the diagram, the second aircraft only passed through the wake vortex warning area and did not enter the strictly restricted area or the danger zone.

[0051] Figure 8 The diagram shows the relative positions of the 8th aircraft near the wake vortex warning area, the strictly restricted area, and the danger zone generated by the 9th aircraft. As can be seen from the diagram, the 9th aircraft only passed through the wake vortex warning area and did not enter the strictly restricted area or the danger zone.

[0052] Figure 9 The figure shows the roll angular velocity curves of each aircraft in the cluster affected by the wake vortices of other aircraft when using the method of this application. As can be seen from the figure, the scheme of this application takes into account the influence of the wake vortex of the aircraft in front and makes evasive maneuvers, effectively ensuring that the induced roll angular velocity of the aircraft is kept within the limit range, thus guaranteeing the flight safety of the whole process.

[0053] Comparative Example Under the same initial conditions and application scenario as in the embodiments, 10 aircraft All according to Figure 2 The communication topology shown enables communication with other aircraft.

[0054] The control method on the aircraft is similar to that in the embodiment, except that the normal avoidance acceleration command has been removed, as detailed below: Step 1: The aircraft receives the position, speed and remaining flight time information of neighboring aircraft in real time, and at the same time transmits its own position, speed and remaining flight time information to the neighboring aircraft. Step 2: Generate normal guidance acceleration commands based on proportional guidance method to control the aircraft to fly toward the target; No. Normal guidance acceleration command for the aircraft Obtained through the following formula (i): (one) in, This represents the proportional guidance coefficient, with a value of 4. Indicates the first The speed of the aircraft; Indicates the first The line-of-sight angular velocity between the aircraft and its target.

[0055] Step 3: Based on the received remaining flight time information of neighboring aircraft, generate axial acceleration commands to eliminate arrival time errors of individual aircraft in the cluster. In step 3, the first The axial acceleration command on the aircraft is obtained by the following formula (iv): (Four) in, Indicates the first Consistency error in estimated arrival time of individual aircraft within the cluster; This represents the coefficient used to adjust the axial acceleration of the aircraft; its value is 0.5. This represents the proportional coefficient of the coordinated guidance law within a finite time, and its value is 0.8.

[0056] The first Consistency error in estimated arrival time of individual aircraft within the cluster Obtained through the following formula (5): (five) in, Represents the first in the cluster One aircraft, This indicates the total number of aircraft in the cluster; Indicates the first The aircraft and the first The communication relationship between the aircraft, when the first The aircraft and the first When individual aircraft can communicate and exchange information The value is 1 if it is set to 1, otherwise the value is 0. Indicates the first The estimated arrival time of each aircraft; Indicates the first The estimated arrival time of an aircraft is obtained based on the remaining flight time.

[0057] No. Remaining flight time for each aircraft Obtained through the following formula (VI): (six) in, Indicates the first The relative distance between an aircraft and its target; Indicates the first The relative speed between the aircraft and its target.

[0058] Step 4: Integrate the normal guidance acceleration command and the axial acceleration command to form a general control command, and control the aircraft to fly toward the target through the aircraft's control system.

[0059] Specific simulation results are as follows: Figure 10 As shown.

[0060] Figure 10 The figure shows the roll velocity curves of each aircraft in the cluster affected by the wake vortices of other aircraft when the method of this application is not used, i.e., vortex avoidance is not performed. This figure demonstrates that failing to avoid wake vortices poses flight safety risks. Figure 9 and Figure 10 The comparison demonstrates the clear advantages of the proposed solution.

[0061] The present invention has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present invention based on these embodiments, all of which fall within the scope of protection of the present invention.

Claims

1. A method for collision avoidance of aircraft swarms based on pre-assigned targets and artificial potential fields, characterized in that, In the process of each aircraft flying independently toward its target in a swarm of aircraft, each aircraft performs the following steps; Step 1: The aircraft receives the position, speed and remaining flight time information of neighboring aircraft in real time, and at the same time transmits its own position, speed and remaining flight time information to the neighboring aircraft. Step 2: Generate normal guidance acceleration commands based on proportional guidance method to control the aircraft to fly toward the target; Step 3: Based on the relative position with the nearby aircraft in front, use an artificial potential field to generate a normal avoidance acceleration command to avoid the wake vortex interference of the aircraft in front. Step 4: Based on the received remaining flight time information of neighboring aircraft, generate axial acceleration commands to eliminate arrival time errors of individual aircraft in the cluster. Step 5: Combine the total normal acceleration command and the axial acceleration command to form a total control command, and control the aircraft to fly toward the target through the aircraft's control system.

2. The pre-assigned target collision avoidance method for aircraft swarms based on artificial potential fields according to claim 1, characterized in that, In step 2, the first Normal guidance acceleration command for the aircraft Obtained through the following formula (i): (one) in, Indicates the proportional guidance coefficient; Indicates the first The speed of the aircraft; Indicates the first The line-of-sight angular velocity between the aircraft and its target.

3. The pre-assigned target collision avoidance method for aircraft swarms based on artificial potential fields according to claim 1, characterized in that, In step 3, when the following aircraft is in the wake warning zone of the preceding aircraft, the normal avoidance acceleration command is obtained by the following formula (ii): (two); When the following aircraft is in the strictly restricted area of ​​the preceding aircraft, the normal avoidance acceleration command is given by the following equation (iii): (three); in, and Each represents a segmentation ratio coefficient independently; A coefficient representing the magnitude of the further constraint repulsive force; Indicates the first The speed of the aircraft; It indicates the distance between the following aircraft and the preceding aircraft.

4. The pre-assigned target collision avoidance method for aircraft swarms based on artificial potential fields according to claim 3, characterized in that, The wake vortex warning region and the strictly restricted region are obtained through the following sub-steps: Sub-step 1: Based on the mass, speed and wingspan parameters of the forward-facing aircraft, obtain the initial circulation of its wake vortex; Sub-step 2: Using the Hallock-Burnham vortex model, based on the position of the vortex core and the real-time circulation intensity, the vertical induced velocity generated by any point in the wake vortex field on the aircraft behind is obtained. This vertical induced velocity is integrated along the wingspan of the aircraft behind to obtain the induced roll moment coefficient generated by the aerodynamic coupling effect. Based on the moment balance relationship, the equivalent induced roll angular velocity required to counteract this moment is derived. Sub-step 3: Retrieve the maximum induced roll angular velocity threshold that the flight control system of the aircraft can stably withstand. The equivalent induced roll angular velocity value is 0.

3. -0.5 The spatial region is defined as the wake vortex warning region, with the equivalent induced roll velocity value set at 0.

5. -0.8 The spatial region is defined as a strictly restricted region.

5. The method for pre-assigned target collision avoidance based on artificial potential field for aircraft swarms according to claim 1, characterized in that, In step 4, the first The axial acceleration command on the aircraft is obtained by the following formula (iv): (Four) in, Indicates the first Consistency error in estimated arrival time of individual aircraft within the cluster; This represents the coefficient used to adjust the axial acceleration of the aircraft; its value is 0.

5. This represents the proportional coefficient of the coordinated guidance law within a finite time, and its value is 0.

8.

6. The pre-assigned target collision avoidance method for aircraft swarms based on an artificial potential field according to claim 5, characterized in that, The first Consistency error in estimated arrival time of individual aircraft within the cluster Obtained through the following formula (5): (five) in, Represents the first in the cluster One aircraft, This indicates the total number of aircraft in the cluster; Indicates the first The aircraft and the first The communication relationship between the aircraft, when the first The aircraft and the first When individual aircraft can communicate and exchange information The value is 1 if it is set to 1, otherwise the value is 0. Indicates the first The estimated arrival time of each aircraft; Indicates the first The estimated arrival time of an aircraft is obtained based on the remaining flight time.

7. The pre-assigned target collision avoidance method for aircraft swarms based on an artificial potential field according to claim 6, characterized in that, No. Remaining flight time for each aircraft Obtained through the following formula (VI): (six) in, Indicates the first The relative distance between an aircraft and its target; express The derivative of, i.e., the first The relative speed between the aircraft and its target.

8. The pre-assigned target collision avoidance method for aircraft swarms based on artificial potential fields according to claim 1, characterized in that, In step 5, the first The total normal acceleration command for the aircraft Obtained through the following formula (vii); (seven).

9. The method for pre-assigned target collision avoidance based on artificial potential field for aircraft swarms according to claim 3, characterized in that, when ,and At that time, or when ,and hour, ; when ,and At that time, or when ,and hour, ; in, Indicates the first The heading angle of the aircraft.

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