Unmanned aerial vehicle cluster area revisit coverage method and system based on micro-closed air route

Abstract

The invention discloses an unmanned aerial vehicle cluster area revisit coverage method and system based on a micro-closed air route, and relates to the unmanned aerial vehicle technology, and the method comprises the steps: configuring the area revisit coverage parameters of an unmanned aerial vehicle cluster, and calculating an area convex hull polygon; determining the length direction and the width direction of the calculated region convex hull polygon, and determining the region coverage direction; rotating the convex hull polygon based on the clock angle of the area coverage direction, and calculating an initial coverage node based on the rotated convex hull polygon; adjusting the calculated initial coverage node to repair an uncovered area; and calculating a cooperative revisit coverage path of the unmanned aerial vehicle cluster according to the adjusted coverage node. The embodiment of the invention provides the method for realizing unmanned aerial vehicle cluster area revisit coverage, which is safe, high in collaboration degree and low in unmanned aerial vehicle demand.

Description

Technical Field

[0001] The present application relates to the field of drone technology, and in particular to a method and system for revisiting and covering an area of ​​a drone cluster based on a differentiable closed route. Background Art

[0002] Many real-world applications require drone swarms to revisit and cover an irregular target area in the most efficient way to discover possible moving targets. This involves how to plan routes for drone swarms so that the swarms can collaboratively revisit and cover any target area. However, existing technologies require too many drones and are inefficient. Summary of the invention

[0003] The embodiments of the present application provide a method and system for revisiting and covering an area of ​​a drone cluster based on a differentiable closed route, so as to provide a method for achieving revisiting and covering an area of ​​a drone cluster that is safe, highly coordinated, and requires few drones.

[0004] The embodiment of the present application provides a method for revisiting and covering a UAV cluster area based on a differentiable closed route, comprising:

[0005] Configure the parameters of the area revisit coverage of the drone cluster and calculate the area convex hull polygon;

[0006] Determine the length direction and width direction of the calculated area convex hull polygon, and determine the area coverage direction;

[0007] Rotate the convex hull polygon based on the clock angle of the area coverage direction, and calculate the initial coverage node based on the rotated convex hull polygon;

[0008] The calculated initial coverage nodes are adjusted to fill the uncovered areas;

[0009] According to the adjusted coverage nodes, the coordinated revisit coverage path of the drone cluster is calculated.

[0010] Optionally, the parameters for configuring the area revisit coverage of the drone cluster include:

[0011] Define the cruising speed of each drone in the cluster as V uav , the detection field of view of each drone is a circular area with a circular field radius of R. The effective detection range is equivalent to a rectangular area with a length of L1 and a width of L2. The detection offset angle is α, the distance between the center of the field of view and the drone position is d, the area coverage requires a detection overlap rate of ρ, and the minimum speed of the target is V tgt,min , the maximum speed is V tgt,max , satisfying V tgt,max <V uav ;

[0012] Computing the convex hull polygon of a region involves:

[0013] Select a set number of points on the boundary of the area, and the selected points form a polygon;

[0014] Calculating the convex polygon of the polygon using a Graham scan algorithm;

[0015] The vertex set of the convex polygon to be calculated is {p1,p2,L,p J-1 ,p J}, where p1 is the point with the smallest ordinate and the leftmost position.

[0016] Optionally, determining the length direction and width direction of the calculated area convex hull polygon, and determining the area coverage direction includes:

[0017] The length and width of the convex polygon are calculated using the radial function method. The length direction is used as the area coverage direction, and the length and width of the convex polygon are recorded as L max and h min , the clock angle of the convex polygon covering direction is recorded as θ opt .

[0018] Optionally, the convex hull polygon is rotated based on the clock angle of the area coverage direction including:

[0019] The convex hull polygon is rotated by the clock angle of the direction covered by the region to obtain the rotated convex hull polygon, and the vertex set of the rotated convex polygon is recorded as {q1,q2,L,q J-1 ,q J}, where q1 is the point with the smallest ordinate and the leftmost position, and the smallest ordinate is marked as y min .

[0020] Optionally, calculating the initial coverage node based on the rotated convex hull polygon includes:

[0021] Calculate the effective detection width L'1 = (1-ρ) L1;

[0022] Calculate the number of covered rows

[0023] According to the number of covered rows, when the number of covered rows N r = 1, the two nodes of the covering row are points and point [100,y min +h min / 2] T The two intersection points of the determined straight line and the rotated convex polygon, where is the ceiling rounding function;

[0024] When the number of covered rows N r >1 and L1 / 2+(Nr -1)L'1<h min When the two nodes corresponding to the i-th covering row are connected by the point and Point The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r ;

[0025] When the number of covered rows N r >1 and L1 / 2+(N r -1)L'1≥h min When the two nodes corresponding to the i-th covering row are connected by the point and Point The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r -1, Nth r The two nodes corresponding to the covering row are the Nth r -1 The two intersection points of the covering row add L'1 to the ordinate component;

[0026] Set the height of each covered node to h uav , each covering row i (i=1,2,L,N r )'s left and right nodes are denoted as r 2i-1 、r 2i .

[0027] Optionally, adjustments are made to the calculated initial coverage node to patch uncovered areas including:

[0028] For each node in the covered row, move it horizontally by the following distance:

[0029]

[0030] Where β is the clock angle of the convex polygon edge where the node is located, γ = β-π / 2;

[0031] For the rotated convex polygon, when the number of covered rows N r >1 and L1 / 2+(N r -1)L'1≥h min When N r -1 The intersection points of the covering upper bound line and the convex polygon of the covering row are denoted as The Nth r The two nodes corresponding to the covered rows are adjusted to

[0032]

[0033] Optionally, also include:

[0034] Along the ray Add a return node So that: line segment The length of the return node is ΔL; The height is h uav +Δh;

[0035] Add a return node along ray r2r1 So that: line segment The length of the return node is ΔL; The height is h uav +Δh;

[0036] The set of coverage nodes and return nodes is denoted as

[0037] Optionally, according to the adjusted coverage nodes, calculating the coordinated revisit coverage path of the drone cluster includes:

[0038] For every two adjacent nodes, the shortest Dubins curve is used to connect them to obtain a closed segmented Dubins curve path. The length of the Dubins curve path is calculated as L. path ;

[0039] Calculate the number of drones required to meet:

[0040]

[0041] Calculate the route distance between adjacent drones to satisfy:

[0042]

[0043] in

[0044] The regional revisit coverage strategy of drone swarms meets the following requirements:

[0045] The drone cluster consists of N drones, each of which is evenly distributed on a closed piecewise Dubins curve path, and the path distance between two adjacent drones is d.

[0046] An embodiment of the present application also proposes a drone cluster area revisit coverage system based on a differentiable closed path, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the drone cluster area revisit coverage method based on a differentiable closed path are implemented as described above.

[0047] The embodiments of the present application provide a method for achieving regional revisit coverage of drone clusters that is safe, highly coordinated, and requires few drones.

[0048] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0050] Figure 1 This is a basic flow diagram of the drone cluster area revisit coverage method according to an embodiment of the present application;

[0051] Figure 2 A schematic diagram of a drone detection area of ​​a drone cluster area revisit coverage method according to an embodiment of the present application;

[0052] Figure 3 This is a diagram illustrating coverage gaps in the drone cluster area revisit coverage method according to an embodiment of the present application;

[0053] Figure 4 This is a schematic diagram of the coverage vulnerability repair principle of the drone cluster area revisit coverage method in an embodiment of the present application;

[0054] Figure 5 This is a schematic diagram of the last row node adjustment principle of the drone cluster area revisit coverage method in an embodiment of the present application;

[0055] Figure 6 This is a schematic diagram of the revisited coverage route of the example of the embodiment of the present application;

[0056] Figure 7 The following is a schematic diagram of the arrangement of the drone cluster in the example of the embodiment of the present application;

[0057] Figure 8 It is a diagram showing the change of the detected target ratio over time in the example of the embodiment of the present application;

[0058] Fig. 9 A schematic diagram of the grid strategy (as a traditional strategy for comparison) of the example of the embodiment of the present application;

[0059] Fig.10 This is a comparison diagram of the number of drones required for the differentiable closing strategy and the grid strategy when the length of the fixed rectangular area in the example of the embodiment of the present application is 3000 meters. DETAILED DESCRIPTION

[0060] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0061] The present application embodiment provides a method for revisiting and covering a UAV cluster area based on a differentiable closed route, such as Figure 1 As shown, the following steps are included:

[0062] In step S101, the parameters of the area revisit coverage of the drone cluster are configured, and the area convex hull polygon is calculated.

[0063] In step S102, the length direction and width direction of the calculated area convex hull polygon are determined, and the area coverage direction is determined.

[0064] In step S103, the convex hull polygon is rotated based on the clock angle of the area coverage direction, and an initial coverage node is calculated based on the rotated convex hull polygon.

[0065] In step S104, the calculated initial coverage nodes are adjusted to repair the uncovered areas.

[0066] In step S105, the collaborative revisit coverage path of the drone cluster is calculated based on the adjusted coverage nodes.

[0067] The embodiments of the present application provide a method for achieving regional revisit coverage of drone clusters that is safe, highly coordinated, and requires few drones.

[0068] In some embodiments, Figure 2 As shown in the figure, the parameters for configuring the area revisit coverage of the drone cluster include:

[0069] Define the cruising speed of each drone in the cluster as V uav , the detection field of view of each drone is a circular area with a circular field radius of R. The effective detection range is equivalent to a rectangular area with a length of L1 and a width of L2. The detection offset angle is α, and the distance between the center of the field of view and the position of the drone is d. The detection overlap rate required for regional coverage is ρ (0<ρ<1) to facilitate subsequent image stitching and other work. The minimum speed of the target is set to V tgt,min , the maximum speed is V tgt,max , satisfying V tgt,max <V uav .

[0070] The area to be revisited is a planar area, which may be convex or concave. The regional revisit coverage problem of drone swarms refers to planning a collaborative coverage path for the drone swarm so that the drone swarm can continuously cover the target area, that is, each point in the area can be revisited at regular intervals and the moving targets in it can be detected in a relatively short time.

[0071] Computing the convex hull polygon of a region involves:

[0072] Select a set number of points on the boundary of the area, and the selected points form a polygon;

[0073] Calculating the convex polygon of the polygon using a Graham scan algorithm;

[0074] The vertex set of the convex polygon to be calculated is {p1,p2,L,p J-1 ,p J}, where p1 is the point with the smallest ordinate and the leftmost position.

[0075] In some embodiments, determining the length direction and the width direction of the calculated area convex hull polygon, and determining the area coverage direction includes:

[0076] The length and width of the convex polygon are calculated using the radial function method. The length direction is used as the area coverage direction, and the length and width of the convex polygon are recorded as L max and h min , the clock angle of the convex polygon covering direction is recorded as θ opt .

[0077] In some embodiments, rotating the convex hull polygon based on the clock angle of the area coverage direction includes:

[0078] The convex hull polygon is rotated by the clock angle of the direction covered by the region to obtain the rotated convex hull polygon, and the vertex set of the rotated convex polygon is recorded as {q1,q2,L,q J-1 ,q J}, where q1 is the point with the smallest ordinate and the leftmost position, and the smallest ordinate is marked as y min .

[0079] In some embodiments, for the rotated convex polygon, calculating the initial covering node includes:

[0080] Calculate the effective detection width L'1 = (1-ρ) L1;

[0081] Calculate the number of covered rows

[0082] According to the number of covered rows, when the number of covered rows N r = 1, the two nodes of the covering row are points and point [100,y min +h min / 2] T The two intersection points of the determined straight line and the rotated convex polygon, where is the ceiling rounding function;

[0083] When the number of covered rows N r >1 and L1 / 2+(N r -1)L'1<h min When the two nodes corresponding to the i-th covering row are connected by the point and Point The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r ;

[0084] When the number of covered rows N r >1 and L1 / 2+(N r -1)L'1≥h min When the two nodes corresponding to the i-th covering row are connected by the point and Point The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r -1, Nth r The two nodes corresponding to the covering row are the Nth r -1 The two intersection points of the covering row add L'1 to the ordinate component;

[0085] Set the height of each covered node to h uav , each covering row i (i=1,2,L,N r )'s left and right nodes are denoted as r 2i-1 、r 2i .

[0086] When the nodes calculated according to the above steps cover the area, coverage holes may appear, such as Figure 3 As shown, in some embodiments, adjusting the calculated initial coverage node to repair the uncovered area includes:

[0087] For each node in the covered row, move it horizontally by the following distance:

[0088]

[0089] Among them, β is the clock angle of the convex polygon edge where the node is located, γ=β-π / 2, such as Figure 4 shown.

[0090] For the rotated convex polygon, when the number of covered rows N r >1 and L1 / 2+(N r -1)L'1≥hmin When N r -1 The intersection points of the covering upper bound line and the convex polygon of the covering row are denoted as like Figure 5 As shown, the Nth r The two nodes corresponding to the covered rows are adjusted to

[0091] In some embodiments, the return node is further added by the following steps:

[0092] Along the ray Add a return node So that: line segment The length of the return node is ΔL; The height is h uav +Δh;

[0093] Add a return node along ray r2r1 So that: line segment The length of the return node is ΔL; The height is h uav +Δh;

[0094] The set of coverage nodes and return nodes is denoted as

[0095] In some embodiments, according to the adjusted coverage nodes, calculating the coordinated revisit coverage path of the drone cluster includes:

[0096] For every two adjacent nodes (r i r i+1 ,i=1,2,L,2N r +1, and ), use the shortest Dubins curve to connect, obtain a closed segmented Dubins curve path, and calculate the length of the Dubins curve path as L path ;

[0097] Calculate the number of drones required to meet:

[0098]

[0099] Calculate the route distance between adjacent drones to satisfy:

[0100]

[0101] in

[0102] The regional revisit coverage strategy of drone swarms meets the following requirements:

[0103] The drone cluster consists of N drones, each of which is evenly distributed on a closed piecewise Dubins curve path, and the path distance between two adjacent drones is d.

[0104] Figure 6-Figure 10 An implementation example of the drone cluster area revisit coverage method based on differentiable closed paths according to an embodiment of the present application is shown. Figure 6 The figure shows a drone cluster revisit coverage route for an area, where the shaded area is the area to be covered, the circles are the vertices of the area, the squares are the adjusted coverage nodes, and the closed curve is the cluster revisit coverage route. Figure 7 To show the arrangement of a cluster of 42 drones for revisiting coverage of an area, the distance between every two adjacent drones is the same. Figure 8 The variation of the detected target ratio in the area over time is given. At 56 seconds, all 100 randomly distributed and randomly moving targets in the area are detected by the cluster. Fig. 9 A schematic diagram of the traditional grid strategy is given in Figure 2 for comparison. In this strategy, each drone is responsible for a sub-area and revisits the sub-area by circling continuously. Fig.10 A comparison between the method in the embodiment of the present application and the traditional grid strategy is given in the figure. The length of the rectangular area to be covered is fixed to 3000 meters, and its width is varied from 100 meters to 3000 meters. The number of drones required for each of the two methods is counted. It can be seen that compared with the traditional grid strategy, the number of drones required for the method in the embodiment of the present application is greatly reduced.

[0105] The drone cluster area revisit coverage method of the present application can be used for the area revisit coverage problem of any non-convex area, and a small number of drones are required.

[0106] An embodiment of the present application also proposes a drone cluster area revisit coverage system based on a differentiable closed path, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the drone cluster area revisit coverage method based on a differentiable closed path are implemented as described above.

[0107] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0108] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0109] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0110] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A method for revisiting and covering the area of ​​a UAV cluster based on a differentiable closed route, characterized in that: include: Configure the parameters of the area revisit coverage of the drone cluster and calculate the area convex hull polygon; Determine the length direction and width direction of the calculated area convex hull polygon, and determine the area coverage direction; Rotate the convex hull polygon based on the clock angle of the area coverage direction, and calculate the initial coverage node based on the rotated convex hull polygon; The calculated initial coverage nodes are adjusted to fill the uncovered areas; According to the adjusted coverage nodes, the coordinated revisit coverage path of the drone cluster is calculated.

2. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route according to claim 1, characterized in that: The parameters for configuring the area revisit coverage of the drone cluster include: Define the cruising speed of each drone in the cluster as V uav , the detection field of view of each drone is a circular area with a circular field radius of R. The effective detection range is equivalent to a rectangular area with a length of L1 and a width of L2. The detection offset angle is α, the distance between the center of the field of view and the drone position is d, the area coverage requires a detection overlap rate of ρ, and the minimum speed of the target is V tgt,min , the maximum speed is V tgt,max , satisfying V tgt,max <V uav ; Computing the convex hull polygon of a region involves: Select a set number of points on the boundary of the area, and the selected points form a polygon; Calculating the convex polygon of the polygon using a Graham scan algorithm; The vertex set of the convex polygon to be calculated is {p1,p2,L,p J-1 ,p J }, where p1 is the point with the smallest ordinate and the leftmost position.

3. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 2, characterized in that: Determine the length direction and width direction of the calculated area convex hull polygon, and determine the area coverage direction including: The length and width of the convex polygon are calculated using the radial function method. The length direction is used as the area coverage direction, and the length and width of the convex polygon are recorded as L max and h min , the clock angle of the convex polygon covering direction is recorded as θ opt .

4. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 3, characterized in that: The clock angle rotation convex hull polygon based on the area coverage direction includes: The convex hull polygon is rotated by the clock angle of the direction covered by the region to obtain the rotated convex hull polygon, and the vertex set of the rotated convex polygon is recorded as {q1,q2,L,q J-1 ,q J }, where q1 is the point with the smallest ordinate and the leftmost position, and the smallest ordinate is marked as y min .

5. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 4, characterized in that: Calculating the initial coverage nodes based on the rotated convex hull polygon includes: Calculate the effective detection width L'1 = (1-ρ) L1; Calculate the number of covered rows According to the number of covered rows, when the number of covered rows N r = 1, the two nodes of the covering row are the points [-100, y min +h min / 2] T and point [100,y min +h min / 2] T The two intersection points of the determined straight line and the rotated convex polygon, where is the ceiling rounding function; When the number of rows covered is N r >1 and L1 / 2+(N r -1)L'1<h min When the two nodes corresponding to the i-th covered row are the points [-100,y min +L1 / 2+(i-1)L'1] T and point [100,y min +L1 / 2+(i-1)L'1] T The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r ; When the number of rows covered is N r >1 and L1 / 2+(N r -1)L'1≥h min When the two nodes corresponding to the i-th covered row are the points [-100,y min +L1 / 2+(i-1)L'1] T and point [100,y min +L1 / 2+(i-1)L'1] T The two intersection points of the determined straight line and the rotated convex polygon, where i = 1, 2, L, N r -1, Nth r The two nodes corresponding to the covering row are the Nth r -1 The two intersection points of the covering row add L'1 to the ordinate component; Set the height of each covered node to h uav , each covering row i (i=1,2,L,N r )'s left and right nodes are denoted as r 2i-1 、r 2i .

6. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 5, characterized in that: Adjustments to the computed initial coverage node to patch uncovered areas include: For each node in the covered row, move it horizontally by the following distance: Where β is the clock angle of the convex polygon edge where the node is located, γ = β-π / 2; For the rotated convex polygon, when the number of covered rows N r >1 and L1 / 2+(N r -1)L'1≥h min When N r -1 The intersection points of the covering upper bound line and the convex polygon of the covering row are denoted as The Nth r The two nodes corresponding to the covered rows are adjusted to 7. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 6, characterized in that: Also includes: Along the ray Add a return node So that: line segment The length of the return node is ΔL; The height is h uav +Δh; Add a return node along ray r2r1 So that: line segment The length of the return node is ΔL; The height is h uav +Δh; The set of coverage nodes and return nodes is denoted as 8. The method for revisiting and covering the area of ​​a drone cluster based on a differentiable closed route as claimed in claim 7, characterized in that: According to the adjusted coverage nodes, the coordinated revisit coverage path of the drone cluster is calculated including: For every two adjacent nodes, the shortest Dubins curve is used to connect them to obtain a closed segmented Dubins curve path. The length of the Dubins curve path is calculated as L. path ; Calculate the number of drones required to meet: Calculate the route distance between adjacent drones to satisfy: in The regional revisit coverage strategy of drone swarms meets the following requirements: The drone cluster consists of N drones, each of which is evenly distributed on a closed piecewise Dubins curve path, and the path distance between two adjacent drones is d.

9. A UAV cluster area revisit coverage system based on differentiable closed routes, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the steps of the method for revisiting and covering an area of ​​a drone cluster based on a differentiable closed route as described in any one of claims 1 to 8 are implemented.

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