A load dropping method of a swarm aircraft aiming at a large target

Abstract

The application discloses a load dropping method for a cluster aircraft aiming at a large target. In the method, the large target is divided into a plurality of sub-regions based on the position and shape of the large target, each sub-region corresponds to a load dropping target of an aircraft, a load dropping window is set for each aircraft based on the specific target, and the formation condition of the plurality of aircrafts, especially the flight height of the aircrafts in the formation, is adjusted, so that the plurality of aircrafts in the aircraft formation can synchronously enter the load dropping window and simultaneously perform the load dropping task.

Description

Technical Field

[0001] This invention belongs to the field of aircraft swarm control technology, and particularly relates to a method for coordinated control of aircraft swarms targeting specific targets, specifically a method for payload delivery by swarm aircraft targeting large targets. Background Technology

[0002] Unmanned aerial vehicles (UAVs) have advantages such as low cost and ease of use, and are widely used.

[0003] However, as application environments become increasingly complex and mission requirements become more diverse, the limitations of using a single UAV with payloads are becoming increasingly apparent. In civilian applications, such as delivering supplies for disaster relief or conducting firefighting operations against large wildfires, a single UAV cannot achieve the required delivery efficiency and coverage area. Because of these challenges, UAV swarm payload delivery technology has received significant attention and is being vigorously developed.

[0004] Unmanned aerial vehicle (UAV) swarm technology is not simply an aggregation of the number of UAVs. Rather, it fully utilizes the flexibility, maneuverability, and other advantages of the UAVs themselves, as well as the multiplier effect that emerges from the consistent and coordinated behavior of the swarm, to improve the application efficiency of the UAV swarm, thereby improving the efficiency and accuracy of payload delivery, leveraging its unique advantages to complete payload delivery tasks that are difficult for a single UAV platform to accomplish.

[0005] However, the selection of payload delivery methods for swarm aircraft is influenced by many factors, such as the delivery environment and the type of mission target. The rules governing payload delivery by swarm aircraft and effective automatic control are all pressing practical problems that need to be addressed, yet domestic research in this area is limited. Faced with increasingly complex application environments and diverse mission requirements, how to efficiently design swarm aircraft payload delivery methods for specific large mission targets, achieve accurate delivery to large targets, improve mission success rates and application efficiency, and more effectively leverage the advantages of collaborative applications of unmanned aerial vehicle swarms has become an urgent issue to be solved.

[0006] Based on the above problems, in order to fully leverage the collaborative advantages of swarm aircraft and accurately deliver payloads to cover large targets, the inventors have conducted in-depth research on payload delivery methods, hoping to design a payload delivery method for large targets using swarm aircraft that can solve the above problems. Summary of the Invention

[0007] To overcome the above problems, the inventors conducted intensive research and designed a method for payload delivery to large targets by swarm aircraft. In this method, based on the position and shape of the large target, the large target is divided into multiple sub-regions, and each sub-region corresponds to a payload delivery target for an aircraft. Based on the specific target, a payload delivery window is set for each aircraft. Then, by adjusting the formation of multiple aircraft, especially the flight altitude of the aircraft in the formation, multiple aircraft in the formation can synchronously enter the payload delivery window and simultaneously perform the payload delivery task, thereby completing the invention.

[0008] Specifically, the purpose of this invention is to provide a method for payload delivery by swarm aircraft to large targets, the method comprising the following steps:

[0009] Step 1: Obtain the location and shape of the large target, and divide the target into multiple sub-regions according to the effective range of the load;

[0010] Step 2: Determine the number of aircraft in the cluster based on the number of sub-regions, and assign a sub-region as the target for each aircraft;

[0011] Step 3: Set the payload delivery window for each aircraft;

[0012] Step 4: Based on the safe distance between the aircraft and the arrangement of the targets, form an aircraft formation and control the aircraft to maintain the formation and fly towards the payload delivery window;

[0013] Step 5: Based on the arrangement of the targets and the type of the large targets, control the flight altitude of each row of aircraft in the formation and set the timing for payload release.

[0014] In step 1, the effective range of the load is able to cover at least one sub-region.

[0015] In step 3, each aircraft obtains its payload delivery window through the following sub-steps:

[0016] Sub-step 1: Based on the load delivery method and wind field information at the target location, set the delivery height and simulate the average landing point and circular error probability (CEP) values ​​obtained from multiple deliveries.

[0017] Sub-step 2: Obtain the offset range corresponding to the deployment height in sub-step 1;

[0018] Sub-step 3: Adjust the set release altitude, repeat sub-step 1 and sub-step 2 multiple times to obtain the offset range corresponding to different release altitudes; Sub-step 4: Obtain the aircraft payload release window through data fitting.

[0019] Among them, in sub-step 1, the value of the CEP is obtained by the following formula (1):

[0020] CEP = 1.1774σ (1)

[0021] Among them, σ represents the standard deviation.

[0022] Preferably, the standard deviation σ is obtained by the following formula (2):

[0023]

[0024] Among them, σ

[0030] ,

[0033] represents the standard deviation in the x direction,

[0025] σ z represents the standard deviation in the z direction.

[0026] Among them, the standard deviation in the x direction and the standard deviation in the z direction are obtained by the following formula (3):

[0027]

[0028] Among them, x i represents the x-axis coordinate of the landing point of the i-th drop,​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​The offset range includes:

[0041] Lateral offset range (z-axis offset range) z 偏 =(z min , z max )

[0042] Longitudinal range (x-axis offset range) x 偏 =(x min x max ).

[0043] In sub-step 3, the following drop height is simulated, and the corresponding offset range is obtained:

[0044] 50m, 100m, 200m, 300m, 400m, 500m, 650m, 800m and 1000m.

[0045] In sub-step 4, cubic spline interpolation is used to fit the offset range corresponding to each delivery altitude obtained in sub-step 3, thereby obtaining the aircraft payload delivery window.

[0046] In step 4, the formation corresponds to the position of the target, and the minimum distance between adjacent aircraft is greater than the safe distance.

[0047] In step 5, the flight altitude of aircraft in the same row is consistent. By controlling the relative flight altitude between each row of aircraft, the aircraft can enter their respective payload delivery windows at the same time and then deliver the payload simultaneously.

[0048] The beneficial effects of this invention include:

[0049] (1) According to the method for delivering payloads to large targets by cluster aircraft provided by the present invention, the method is applicable to actual complex application environments and mission requirements, and can stably and accurately obtain the corresponding delivery windows of the aircraft payloads to the center of each sub-region, and design a cluster aircraft payload delivery scheme accordingly to achieve accurate delivery to each sub-region of the large target.

[0050] (2) According to the method for delivering payloads to large targets by cluster aircraft provided by the present invention, the delivery time of the aircraft is controlled by adjusting the flight altitude of the aircraft. The method has the characteristics of better sensitivity, maneuverability and coverage of large targets.

[0051] (3) According to the payload delivery method of the cluster aircraft for large targets provided by the present invention, for the scenario of the cluster aircraft delivering payloads to large targets under different mission requirements and environmental conditions, only by changing the corresponding payload delivery model, wind field model, aircraft model and large target model, the delivery window of each area center under different mission requirements and environmental conditions can be obtained, and the corresponding cluster aircraft payload delivery scheme can be designed accordingly.

[0052] (4) The payload delivery method for large targets by cluster aircraft provided by the present invention takes into account the influence of wind disturbance on the payload delivery process, is applicable to complex application environments and mission requirements in actual use, achieves accurate delivery, and improves efficiency in actual use due to simple calculation. It also takes into account diverse mission requirements and the types of payloads are diverse. Attached Figure Description

[0053] Figure 1 This paper presents an overall logic diagram of a method for delivering payloads to large targets using swarm aircraft, as described in this application.

[0054] Figure 2 This diagram illustrates how a large target is divided into six sub-regions in an embodiment.

[0055] Figure 3 This diagram illustrates different load delivery windows in the embodiments.

[0056] Figure 4 This diagram illustrates the formation of six aircraft in the embodiment.

[0057] Figure 5 The diagram shows the distances between the six final load landing points and the target obtained in the embodiment. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] This invention provides a method for payload delivery by swarm aircraft to large targets, such as... Figure 1 As shown, the method includes the following steps:

[0061] Step 1: Obtain the location and shape of the large target, and divide the target into multiple sub-regions according to the effective range of the load;

[0062] The large targets described in this application can be, for example, forest fires, with fire extinguishing bombs deployed as payloads, or disaster-stricken areas affected by earthquakes, floods, or other natural disasters, with relief supplies such as living materials deployed as payloads. The method proposed in this application has high versatility. Preferably, the effective range of the payload is related to the type and size of the payload, and can be selected and set according to specific circumstances.

[0063] Preferably, the large target can be divided into multiple rectangular sub-regions by using a rectangular frame, so that the effective range of the load can cover at least one sub-region, and on this basis, the effective ranges of connected loads overlap as little as possible.

[0064] Step 2: Determine the number of aircraft in the cluster based on the number of sub-regions, and assign a sub-region as the target for each aircraft;

[0065] Preferably, for each sub-region, a corresponding payload-carrying aircraft is configured. The flight direction of the aircraft and the ideal landing point of the payload are both the center point of the target corresponding to the aircraft.

[0066] Step 3: Set the payload delivery window for each aircraft;

[0067] In step 3, each aircraft obtains its payload delivery window through the following sub-steps:

[0068] Sub-step 1: Based on the load delivery method and wind field information at the target location, set the delivery height and simulate the average landing point and circular error probability (CEP) values ​​obtained from multiple deliveries.

[0069] In sub-step 1, the Monte Carlo shooting method is used to simulate the impact point dispersion of the payload. The payload delivery method includes information such as the payload's external dimensions, mass, trajectory tilt angle at the time of delivery, and roll angle, as well as the position and attitude information of the aircraft at the moment of delivery.

[0070] The wind field information includes wind speed magnitude and wind speed direction.

[0071] The average x-axis coordinate of all landing points is the average x-axis coordinate of the landing point, and the average z-axis coordinate of all landing points is the average z-axis coordinate of the landing point.

[0072] The circular probability deviation (CEP) measures the accuracy of payload delivery by an aircraft. It is defined as follows: half of the payloads land within a circle centered on the average landing point. The radius R of this circle is called the CEP.

[0073] Preferably, in sub-step 1, the value of CEP is obtained by the following formula (a):

[0074] CEP = 1.1774σ (1)

[0075] Among them, σ represents the standard deviation. In this application, setting the value of CEP to 1.1774 times the standard deviation as above can make the finally obtained release window more accurate, ensure that the payload thrown within this release window can fall within the planned area, be close enough to the target center point, and achieve the predetermined effect.

[0076] More preferably, the standard deviation σ is obtained by the following formula (2):

[0077]

[0078] Among them, σ x represents the standard deviation in the X direction,

[0079] σ z represents the standard deviation in the Z direction.

[0080] The standard deviation in the x direction and the standard deviation in the z direction are obtained by the following formula (3):

[0081]

[0082] Among them, x i represents the x-axis coordinate of the landing point of the i-th release,

[0083] z i represents the z-axis coordinate of the landing point of the i-th release,

[0084] represents the x-axis coordinate of the average release landing point,

[0085] represents the z-axis coordinate of the average release landing point,

[0086] n represents the number of releases. In sub-step 1, based on each release height, at least 100 releases are simulated. In order to shorten the simulation time, it can be specifically set to 100 releases, that is, n = 100.

[0087] The coordinate system in this application: The projection of the flight direction of the aircraft on the horizontal plane is the x-axis direction, the vertical direction is the y-axis direction, and the direction perpendicular to xy is the z-axis direction.

[0088] Sub-step 2, obtain the offset range corresponding to the release height in sub-step 1;

[0089] In sub-step 2, first obtain the extreme value coordinates corresponding to the release height,

[0090] Then obtain the offset range based on the extreme value coordinates.

[0091] Preferably, the extreme coordinates include:

[0092] Maximum coordinates of x-axis offset

[0093] Minimum coordinates of x-axis offset

[0094] Minimum coordinates of z-axis offset

[0095] Maximum coordinates of the offset in the z-axis direction

[0096] The offset range includes:

[0097] Lateral offset range (z-axis offset range) z 偏 =(z min , z max )

[0098] Longitudinal range (x-axis offset range) x 偏 =(x min x max ).

[0099] Sub-step 3: Adjust the set deployment height, and repeat sub-step 1 and sub-step 2 multiple times to obtain the offset range corresponding to different deployment heights;

[0100] In sub-step 3, the following drop height is simulated, and the corresponding offset range is obtained:

[0101] 50m, 100m, 200m, 300m, 400m, 500m, 650m, 800m and 1000m.

[0102] The inventors have discovered that by setting the above nine height dimensions, an accurate payload delivery window can be obtained, and the coverage of this payload delivery window can meet the needs of common task types.

[0103] Sub-step 4: Obtain the aircraft payload delivery window through data fitting.

[0104] In sub-step 4, cubic spline interpolation is used to fit the offset range corresponding to each delivery altitude obtained in sub-step 3, thereby obtaining the aircraft payload delivery window.

[0105] Preferably, the fitting is performed using the "spline" function of MATLAB's interp1 algorithm.

[0106] The obtained aircraft payload delivery window is a three-dimensional spatial region. When the aircraft enters this spatial region, the delivery task is performed, which means that the delivered payload can fall near the target center point.

[0107] Step 4: Based on the safe distance between the aircraft and the arrangement of the targets, form an aircraft formation and control the aircraft to maintain the formation and fly towards the payload delivery window;

[0108] In step 4, the formation corresponds to the position of the target, and the minimum distance between adjacent aircraft is greater than the safe distance.

[0109] In this application, the center point position of each target is determined, and the shape of the aircraft formation is arranged according to the shape formed by all the center points, and the two shapes are consistent.

[0110] Based on path planning, each aircraft flies towards its corresponding payload delivery window in a straight line as much as possible. During flight, if it encounters obstacles or disturbances, each aircraft can guide and control itself. With the target coordinates known in advance, it can obtain its own position information in real time based on radar or GPS, and can control the aircraft to avoid obstacles and fly towards the target relatively accurately and stably.

[0111] Step 5: Based on the arrangement of the targets and the type of the large targets, control the flight altitude of each row of aircraft in the formation and set the timing for payload release.

[0112] In step 5, the flight altitude of aircraft in the same row is consistent. By controlling the relative flight altitude between each row of aircraft, the aircraft can enter their respective payload delivery windows at the same time and then deliver the payload simultaneously.

[0113] In this application, the effective range of the aircraft payload can be understood as a circular area centered on the landing point and with the effective distance as the radius. Since in actual operation, this radius will be larger than the safe distance between adjacent aircraft, the flight altitude of the foremost aircraft can be controlled to be as low as possible, with each subsequent row of aircraft flying at a relatively higher altitude. Of course, the minimum flight altitude of the aircraft should still be set based on the type of large target. For example, when dropping fire extinguishing bombs, the flight altitude must be high enough to ensure that the aircraft's flight status is not affected by airflow. When dropping disaster relief supplies, the flight altitude can be as low as possible to facilitate locating and determining the landing point of the supplies.

[0114] Example

[0115] A large target, approximately rectangular in shape, measuring 60m in length and 40m in width, is designed. A swarm of aircraft will deploy payloads to this target. The payloads are cylindrical, missile-like structures. The technical parameters of the payloads are shown in Table 1 below.

[0116] Table 1 Technical Parameters

[0117] Technical parameters value Total weight 1.25kg full length 278mm radius 60mm

[0118] The roll angle of the payload is always 0°, and it is dropped horizontally (ballistic inclination angle θ = 0°).

[0119] Under the ideal conditions of the position and attitude of the unmanned aerial vehicle at the moment of payload release, the parameter data of the unmanned aerial vehicle at the release moment are shown in Table 2.

[0120] Table 2 Parameters of the aircraft at the release moment

[0121]

[0122] There is wind disturbance at the target. Since the take-off position of the aircraft is relatively close to the target position, the wind field information at the take-off position of the aircraft is used to replace the wind field information at the target position. The specific wind field information is shown in Table 3 below:

[0123] Table 3 Wind field information

[0124] wind direction Speed ​​(m / s) Random error (m / s) WindX 0 -2～2 crosswind 0 -2～2

[0125] The specific operation process is as follows:

[0126] Step 1: Obtain the position and shape of the large target, and divide the target into 6 sub-regions according to the action range of the payload. The side length of each sub-region is 20 m; as Figure 2 shown in

[0127] Step 2: Determine that the number of aircraft in the cluster is 6 based on the number of the sub-regions, and assign a sub-region as the target to each aircraft. Specifically, the center point of the sub-region is used as the target.

[0128] Step 3: Set a payload release window for each aircraft. For each aircraft, the following sub-steps are specifically executed:

[0129] Sub-step 1: Based on the payload release form and the wind field information at the target, set the release height to 50 m, and use the Monte Carlo shooting method to simulate the average landing point and the value of the circular error probability CEP obtained from 100 releases.

[0130] The value of the CEP is obtained by the following formula (1):

[0131] CEP = 1.1774σ (1)

[0132] The standard deviation σ is obtained by the following formula (2):

[0133]

[0134] where, σ x represents the standard deviation in the X direction,

[0135] σ zThis represents the standard deviation in the Z direction.

[0136] The standard deviations in the x-direction and z-direction are obtained by the following formula (iii):

[0137]

[0138] Where, x i The z-axis coordinate represents the x-coordinate of the i-th drop point. i This represents the z-axis coordinate of the i-th drop point.

[0139] The x-axis coordinate represents the average landing point of the drop.

[0140] The z-axis coordinate represents the average drop point.

[0141] n = 100.

[0142] Sub-step 2: Obtain the offset range corresponding to the deployment height in sub-step 1; first, obtain the extreme coordinates corresponding to the deployment height.

[0143] Then, the offset range is obtained based on the extreme value coordinates.

[0144] The extreme value coordinates include:

[0145] Maximum coordinates of x-axis offset Minimum coordinates of x-axis offset Minimum coordinates of z-axis offset Maximum coordinates of the offset in the z-axis direction The offset range includes:

[0146] Lateral offset range (z-axis offset range) z 偏 =(z min , z max Longitudinal range (x-axis offset range) x 偏 =(x min x max ).

[0147] Sub-step 3: Adjust the set deployment height, and repeat sub-step 1 and sub-step 2 8 times to obtain the offset ranges corresponding to the following 9 deployment heights.

[0148] 50m, 100m, 200m, 300m, 400m, 500m, 650m, 800m and 1000m.

[0149] Sub-step 4: Use cubic spline interpolation to fit the offset range corresponding to each delivery altitude obtained in sub-step 3, thereby obtaining the aircraft payload delivery window.

[0150] Six aircraft performed the above sub-steps a total of six times, resulting in six payload delivery windows for each aircraft. Since the delivery altitude for large targets in this embodiment cannot be lower than 500 meters, Figure 3 The document only shows the payload delivery window at heights above 500 meters.

[0151] Step 4: Based on the safe distance between the aircraft and the target's position, form an aircraft formation. The aircraft are divided into two rows. The first row targets sub-regions 4, 5, and 6, while the second row targets sub-regions 1, 2, and 3. The aircraft are then controlled to maintain their formation and fly towards the payload delivery window. A schematic diagram of the formation of the six aircraft is shown below. Figure 4 As shown;

[0152] Step 5: Based on the arrangement of the targets and the type of the large targets, control the flight altitude of each row of aircraft in the formation. The flight altitude of the first row of aircraft is 920m, the flight altitude of the second row of aircraft is 940m, and the payload is released 1 second after the aircraft enters the payload release window.

[0153] The final schematic diagram showing the distances between the six load impact points and the target is as follows: Figure 5 As shown. By Figure 5 It can be seen that the payload landing points obtained by the payload delivery method for large targets using swarm aircraft are all located in sub-regions and are close to the center of the sub-regions, which shows that the method has good practical effect.

[0154] 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 payload delivery by swarm aircraft to a large target, characterized in that, The method includes the following steps: Step 1: Obtain the position and shape of the large target, and divide the target into multiple sub-regions according to the action range of the payload; Step 2: Determine the number of aircraft in the cluster based on the number of the sub-regions, and assign a sub-region to each aircraft as the target; Step 3: Set the payload delivery window for each aircraft; Step 4: Form the formation of the aircraft based on the safe distance between the aircraft and the arrangement position of the target; Step 5: Control the flight altitude of each row of aircraft in the formation and set the timing of payload delivery based on the arrangement form of the target and the type of the large target; In Step 3, each aircraft obtains the payload delivery window through the following sub-steps: Sub-step 1: Set the delivery altitude based on the payload delivery form and the wind field information at the target, and simulate the average landing point and the value of the circular error probability (CEP) obtained from multiple deliveries; Sub-step 2: Obtain the offset range corresponding to the delivery altitude in Sub-step 1; Sub-step 3: Adjust the set delivery altitude, and repeat Sub-step 1 and Sub-step 2 multiple times to obtain the offset ranges corresponding to different delivery altitudes; Sub-step 4: Obtain the payload delivery window of the aircraft through data fitting; In Sub-step 1, the value of CEP is obtained through the following formula (I): CEP = 1.1774σ (I) where, σ represents the standard deviation; The standard deviation σ is obtained through the following formula (II): Where, σ x The standard deviation in the x-direction. σ z This represents the standard deviation in the z-direction.

2. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein in Step 1, the action range of the payload can cover at least one sub-region.

3. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein the standard deviation in the x direction and the standard deviation in the z direction are obtained through the following formula (III): Where, x i This represents the x-coordinate of the i-th drop point. z i This represents the z-axis coordinate of the i-th drop point. The x-axis coordinate represents the average landing point of the drop. The z-axis coordinate represents the average drop point. n represents the number of deliveries.

4. The method for payload delivery of a cluster of aircraft against a large target according to claim 3, wherein in Sub-step 2, first obtain the extreme value coordinates corresponding to the delivery altitude, and then obtain the offset range based on the extreme value coordinates; The extreme value coordinates include: Maximum coordinates of x-axis offset Minimum coordinates of x-axis offset Minimum coordinates of z-axis offset Maximum coordinates of the offset in the z-axis direction The offset range includes: z-axis offset range 偏 =(z min , z max ) x-axis offset range x 偏 =(x min x max ).

5. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein in Sub-step 3, simulate the following delivery altitudes and obtain the corresponding offset ranges: 50m, 100m, 200m, 300m, 400m, 500m, 650m, 800m and 1000m.

6. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein in Sub-step 4, use the cubic spline interpolation method to fit the offset ranges corresponding to each delivery altitude obtained in Sub-step 3, so as to obtain the payload delivery window of the aircraft.

7. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein in Step 4, the formation of the aircraft corresponds to the arrangement position of the target, and the minimum distance between adjacent aircraft is greater than the safe distance.

8. The method for payload delivery of a cluster of aircraft against a large target according to claim 1, wherein In step 5, the flight altitude of aircraft in the same row is consistent. By controlling the relative flight altitude between each row of aircraft, the aircraft can enter their respective payload delivery windows at the same time and then deliver the payload simultaneously.

Images