A method for avoiding and handling drone swarms

Abstract

The present application relates to the field of drone avoidance technology, and in particular to a method for avoiding a drone swarm. The method comprises: obtaining a horizontal speed list V of drones in a target drone swarm; traversing V, and calculating the horizontal speed of the drones according to V. i Get the turning radius R of the i-th drone in the target drone group i According to V i and R i Get the turning angular velocity ω of the i-th UAV in the target UAV group i According to d 1 i,j and d 2 i,j Get the target horizontal avoidance distance D between the i-th UAV and the j-th UAV in the target UAV group i,j ; Obtain the target horizontal avoidance distance set D of the target drone group, and determine max(D) as the horizontal avoidance distance between any two drones in the target drone group. The present invention can determine the horizontal avoidance distance between drones in a drone group, reduce the hidden danger of collision of drones in the target drone group in the horizontal direction, and effectively ensure the overall airspace safety.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle avoidance, and in particular to an avoidance processing method for a group of unmanned aerial vehicles. Background Art

[0002] The safe interval (i.e., avoidance distance) of drones in urban low-altitude airspace is the key to ensuring the safe and orderly flight of low-altitude aircraft. In the face of the future large-scale flight needs of multiple types of drones in multiple scenarios, such as multi-rotor drones, fixed-wing drones, and electric vertical take-off and landing (eVTOL), it is necessary to study the dynamic safe interval of drones in low-altitude airspace. For drone swarms including three, four, or even more drones, the relative position relationship of the drones varies. For example, for a drone swarm including four drones, it is possible that two of the drones it includes fly relative to the other two drones, or one of the drones it includes flies relative to the other three drones. How to determine the avoidance distance between drones in a drone swarm to reduce the risk of collision between drones in a drone swarm is an urgent problem to be solved. Summary of the invention

[0003] The object of the present invention is to provide an avoidance processing method for a drone swarm, so as to determine the horizontal avoidance distance between drones in the drone swarm and reduce the hidden danger of collision between drones in the drone swarm in the horizontal direction.

[0004] According to the present invention, a method for avoiding a drone swarm is provided, the method comprising the following steps:

[0005] S100, obtain the horizontal speed list V of the drones in the target drone group, V=(V1, V2, …, V i ,…,V n ), V i is the horizontal speed of the i-th drone in the target drone swarm, the value of i ranges from 1 to n, n is the number of drones included in the target drone swarm, and n≥3.

[0006] S200, traverse V, according to V i Get the turning radius R of the i-th drone in the target drone group i .

[0007] S300, according to V i and R i Get the turning angular velocity ω of the i-th UAV in the target UAV group i .

[0008] S400, obtaining a first horizontal avoidance distance d between the i-th drone and the j-th drone in the target drone group.1 i,j ; , j ranges from 1 to n, and j≠i; R j is the turning radius of the jth UAV in the target UAV swarm, ω j is the turning angular velocity of the jth UAV in the target UAV swarm.

[0009] S500: Obtain the second horizontal avoidance distance d between the i-th UAV and the j-th UAV in the target UAV group. 2 i,j ; .

[0010] S600: Obtain the target horizontal avoidance distance D between the i-th UAV and the j-th UAV in the target UAV group. i,j ;D i,j =min(d 1 i,j ,d 2 i,j ), min() is to find the minimum value.

[0011] S700, obtain the target horizontal avoidance distance set D of the target UAV group, D={D1,D2,…,D k ,…,D q}, D k is the target horizontal avoidance distance of the kth UAV pair in the target UAV swarm, the value range of k is 1 to q, and q is the number of UAV pairs constituting the target UAV swarm.

[0012] S800, max(D) is determined as the horizontal avoidance distance between any two drones in the target drone group; max( ) is the maximum value.

[0013] Compared with the prior art, the present invention has at least the following beneficial effects:

[0014] For the avoidance scenario of a drone group including at least three drones, the present invention first obtains the horizontal speed of each drone in the target drone group, and then further obtains the turning radius and turning angular velocity of each drone in the target drone group; on this basis, the target horizontal avoidance distance of the corresponding two drones is obtained by obtaining the first horizontal avoidance distance and the second horizontal avoidance distance of any two drones in the target drone group, and the maximum value of the target horizontal avoidance distance of any two drones in the target drone group is determined as the horizontal avoidance distance of any two drones in the target drone group, thereby, the present invention obtains the horizontal avoidance distance between the drones in the drone group. The horizontal avoidance distance obtained by the present invention is the avoidance distance in the horizontal direction, and the horizontal avoidance distance obtained by the present invention is determined according to the actual flight parameters of the drones included in the target drone group, and has high accuracy. The horizontal avoidance distance obtained by the present invention is used as a reference for avoiding collision between any two drones in the target drone group in the horizontal direction, which can reduce the hidden danger of collision of drones in the target drone group in the horizontal direction and effectively ensure the overall airspace safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A flowchart of a method for avoiding a swarm of drones provided in an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the case where the horizontal speeds of three machines provided by an embodiment of the present invention are at a relative angle;

[0018] Figure 3 A schematic diagram of horizontal avoidance when three aircraft meet provided by an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of a first horizontal avoidance method when four aircraft meet provided by an embodiment of the present invention;

[0020] Figure 5 A schematic diagram of a second type of horizontal avoidance when four aircraft meet provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0022] According to this embodiment, Figure 1 As shown, a method for avoiding a drone group is provided, and the method comprises the following steps:

[0023] S100, obtain the horizontal speed list V of the drones in the target drone group, V=(V1, V2, …, V i ,…,V n ), V i is the horizontal speed of the i-th drone in the target drone swarm, the value of i ranges from 1 to n, n is the number of drones included in the target drone swarm, and n≥3.

[0024] In this embodiment, the speed of the drone is a vector. The speed of the i-th drone is decomposed into two components: horizontal speed and vertical speed. The decomposed horizontal speed is V i .

[0025] S200, traverse V, according to V i Get the turning radius R of the i-th drone in the target drone group i .

[0026] As a specific implementation, S200 includes:

[0027] S210, obtaining the maximum turning angle θ of the i-th UAV in the target UAV group i .

[0028] In this embodiment, the maximum turning angle of the drone is directly given by the drone manufacturer.

[0029] S220, according to θ i Get the load factor LF of the i-th drone in the target drone group i .

[0030] In this embodiment, LF i Satisfies the following relationship: LF i =1 / (cos(θ i )) ’ , ( ) ’ To seek guidance.

[0031] S230, according to V i and LF i Get R i, R i =(V i ×V i ) / (g×((LF i ×LF i -1) 0.5 ) ’ ), where g is the acceleration due to gravity, ( ) ’ For guidance.

[0032] S300, according to V i and R i Get the turning angular velocity ω of the i-th UAV in the target UAV group i .

[0033] In this embodiment, ω i Satisfies the following relationship: i =V i / R i .

[0034] S400, obtaining a first horizontal avoidance distance d between the i-th drone and the j-th drone in the target drone group. 1 i,j ; , j ranges from 1 to n, and j≠i; R j is the turning radius of the jth UAV in the target UAV swarm, ω j is the turning angular velocity of the jth UAV in the target UAV swarm.

[0035] In this embodiment, R j Satisfies the following relationship: R j =(V j ×V j ) / (g×((LF j ×LF j -1) 0.5 ) ’ ), where V j is the horizontal speed of the jth UAV in the target UAV group, LF j is the load factor of the jth UAV in the target UAV group, g is the gravitational acceleration, ( ) ’ To find the derivative. LF j Satisfies the following relationship: LF j =1 / (cos(θ j )) ’ ,θ j is the maximum turning angle of the jth UAV in the target UAV swarm.

[0036] In this embodiment, when n=3, that is, the number of drones included in the target drone group is 3, no matter what mode and angle the three drones included in the target drone group meet at, in general, it can be summarized as two drones meeting each other head-on in the same direction. Even if the three drones in the target drone group meet at a relative angle, it can be essentially summarized as the radial velocity vectors of the two drones meeting the radial velocity vector of another drone, such as Figure 2 As shown, α is the relative angle, D is the horizontal avoidance distance when α is between 0° and 180°, and d avoid is the horizontal avoidance distance when α=0°. When α=0°, Figure 3 As shown in the figure, two drones turn left and right to take evasive action, while the other drone flies straight. After the two drones take evasive action, the tangent point at a certain point reaches the closest distance (Point of Closest Approach, PCA) with the track of the drone with a horizontal speed of V1. After that, the three drones continue to move away, and the PCA gradually increases, finally reaching a stable and safe state.

[0037] When n=4, that is, the number of drones included in the target drone group is 4, no matter how the 4 drones in the target drone group meet in what mode and angle, in general, they can be summarized into two situations, that is, two drones meet head-on with the other two drones, such as Figure 4 As shown in the figure, two drones with horizontal speeds of V1 and V2 meet head-on with another two drones with horizontal speeds of V3 and V4. Then the two drones with horizontal speeds of V3 and V4 begin to adopt a maneuvering avoidance strategy. At a certain point, the tangent line and the track of the two drones with horizontal speeds of V1 and V2 reach PCA. After that, the two drones with horizontal speeds of V3 and V4 continue to turn left and right, and the distance between the four drones continues to increase, and finally reaches a safe and stable state; or three drones meet head-on with one drone, as shown in the figure. Figure 5 As shown in the figure, three drones with horizontal speeds of V1, V2 and V3 meet head-on with another drone with horizontal speed of V4. Then the four drones begin to adopt maneuver avoidance strategies, in which the two drones with horizontal speeds of V1 and V2 turn left respectively, and the two drones with horizontal speeds of V3 and V4 turn right respectively. The smallest PCA is the minimum distance between the tangent line of a certain point when the drone turning with the horizontal speed of V4 avoids to the right and the drone turning left with the horizontal speed of V2, or the minimum distance between the drone turning with the horizontal speed of V4 and the drone turning right with the horizontal speed of V3 when avoiding to the right; finally, the four drones reach a safe and stable state.

[0038] Therefore, the horizontal avoidance distance is derived according to the scenario when the target drone group includes multiple drones. When there are n drones in the target drone group, their speeds are V1, V2, …, V i ,…,V n The turning radii are R1, R2, …, R i ,…,R n , the maximum turning angles are θ1,θ2,…,θ i ,…,θ n For the i-th UAV in the target UAV group, at time t after the turn begins, the position x of the i-th UAV in the two-dimensional plane is i (t) and y i (t) can be expressed as: i (t) = R i ×sin(ω i ×t),y i (t) = R i ×(1-cos(ω i ×t)).

[0039] Considering that each drone has the same height, the distance between the i-th drone and the j-th drone can be expressed as: d ij (t)=((x j (t)-x i (t)) 2 +(y j (t)-y i (t)) 2 ) 0.5 , x i (t), y i (t), x j (t) and y j Substituting (t) into the equation, we get: ij (t)=((R j ×sin(ω j ×t)-R i ×sin(ω i ×t)) 2 +(R j ×(1-cos(ω j ×t))-R i (1-cos(ω j ×t))) 2 ) 0.5 .

[0040] In order to find the minimum distance point, ij(t) Take the derivative with respect to time t and solve for the time points where the derivative is zero. These time points correspond to possible extreme points (i.e., minimum or maximum values). By taking the derivative, find the point where the derivative is zero; in the symbolic solution process, the following two key point expressions are obtained. Among them, the first key point expression is , this expression is obtained by using symmetry or by direct solution when two drones meet at certain symmetrical positions or under certain conditions; this expression is obtained at a specific time point t=π / ω i Or t = π / ω j , solve and substitute, and this is the time point at which the drone may approach the closest distance. Specifically, after substituting the time, we can get the coordinate difference x j (t)-x i (t) = R j ×sin(π×ω j / ω i ) and y j (t)-y i (t) = R i ×cos(π×ω j / ω i )-R j Substituting these coordinate differences into the above distance formula, we can get the above d 1 i,j expression.

[0041] S500: Obtain the second horizontal avoidance distance d between the i-th UAV and the j-th UAV in the target UAV group. 2 i,j ; .

[0042] In this embodiment, another special case is considered, where the i-th UAV and the j-th UAV are moving horizontally at speeds V i and V j Doing uniform circular motion, the turning radii are R i and R j , and their turning angular velocities are: ω i =V i / R i and ω j =V j / R j , their trajectories are circular paths on the plane. Assuming that the two drones are at the same height and are highly stable, for the i-th drone, its position coordinates on the two-dimensional plane are: i (t) = R i ×cos(ω i ×t),y i (t) = R i ×sin(ωi ×t); for the jth UAV, its position coordinates on the two-dimensional plane are: j (t) = R j ×cos(ω j ×t),y j (t) = R j ×sin(ω j ×t); the distance between the two drones is: d ij (t)=((x j (t)-x i (t)) 2 +(y j (t)-y i (t)) 2 ) 0.5 .

[0043] For the i-th drone, at time t=π / ω j When , its position coordinates on the two-dimensional plane are: i (π / ω j )=-R i ×cos(ω j ×π / ω i ), y i (π / ω j )=R i ×sin(ω j ×π / ω i ); For the jth UAV, at time t=π / ω j When , its position coordinates on the two-dimensional plane are: j (π / ω j )=R j ,y j (π / ω j )=0; i (t) and x j (t), and y i (t) and y j Substituting the difference of (t) into the above distance formula, the distance formula between the i-th UAV and the j-th UAV in the horizontal direction is: ij (t)=((R j +R i ×cos(ω j ×π / ω i )) 2 +R 2 i ×sin 2 (ω j ×π / ω i )) 0.5 On this basis, the second key point expression is obtained as , which corresponds to the minimum distance obtained at different time points.

[0044] S600: Obtain the target horizontal avoidance distance D between the i-th UAV and the j-th UAV in the target UAV group. i,j ;D i,j =min(d 1 i,j ,d 2 i,j ), min() is to find the minimum value.

[0045] In this embodiment, d 1 i,j and d 2 i,j The smaller value of is determined as the minimum distance between the i-th UAV and the j-th UAV during the turning process, that is, the target horizontal avoidance distance D between the i-th UAV and the j-th UAV i,j .

[0046] S700, obtain the target horizontal avoidance distance set D of the target UAV group, D={D1,D2,…,D k ,…,D q}, D k is the target horizontal avoidance distance of the kth UAV pair in the target UAV swarm, the value range of k is 1 to q, and q is the number of UAV pairs constituting the target UAV swarm.

[0047] In this embodiment, q=n×(n-1) / 2, if n=3, then q=3; if n=4, then q=6.

[0048] S800, max(D) is determined as the horizontal avoidance distance between any two drones in the target drone group; max( ) is the maximum value.

[0049] In this embodiment, the maximum target horizontal avoidance distance in D is determined as the final safety distance, and the safety distance is used as the horizontal avoidance distance d between any two drones in the target drone group. avoid .

[0050] As a specific implementation, a UI ground station that comes with Ardupilot is used. By using the ground station map, the obstacle avoidance effect of the drone is clearly displayed and monitored. In conjunction with the drone flight control system driven by Ardupilot, python code is used to call drone control, and then a maneuvering avoidance distance experiment is performed; the experiment shows that the horizontal avoidance distance obtained in this embodiment can be used as a safety interval to avoid drone collisions in the target drone group; the three-machine experimental data is shown in Table 1, the four-machine experimental data is shown in Table 2, and the five-machine experimental data is shown in Table 3.

[0051] Table 1

[0052]

[0053] Table 2

[0054]

[0055] Table 3

[0056]

[0057] For the avoidance scenario of a drone group including at least three drones, this embodiment first obtains the horizontal speed of each drone in the target drone group, and then further obtains the turning radius and turning angular velocity of each drone in the target drone group; on this basis, the target horizontal avoidance distance of the corresponding two drones is obtained by obtaining the first horizontal avoidance distance and the second horizontal avoidance distance of any two drones in the target drone group, and the maximum value of the target horizontal avoidance distance of any two drones in the target drone group is determined as the horizontal avoidance distance of any two drones in the target drone group, thereby, this embodiment obtains the horizontal avoidance distance between the drones in the drone group. The horizontal avoidance distance obtained in this embodiment is the avoidance distance in the horizontal direction, and the horizontal avoidance distance obtained in this embodiment is determined according to the actual flight parameters of the drones included in the target drone group, and has high accuracy. The horizontal avoidance distance obtained in this embodiment is used as a reference for avoiding collision between any two drones in the target drone group in the horizontal direction, which can reduce the hidden danger of collision between drones in the target drone group in the horizontal direction and effectively ensure the overall airspace safety.

[0058] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will also be appreciated by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for avoiding a swarm of drones, characterized in that: The method comprises the following steps: S100, obtain the horizontal speed list V of the drones in the target drone group, V=(V1, V2, …, V i ,…,V n ), V i is the horizontal speed of the i-th drone in the target drone group, the value range of i is 1 to n, n is the number of drones included in the target drone group, n ≥ 3; S200, traverse V, according to V i Get the turning radius R of the i-th drone in the target drone group i ; S300, according to V i and R i Get the turning angular velocity ω of the i-th UAV in the target UAV group i ; S400, obtaining a first horizontal avoidance distance d between the i-th drone and the j-th drone in the target drone group. 1 i,j ; , j ranges from 1 to n, and j≠i; R j is the turning radius of the jth UAV in the target UAV swarm, ω j is the turning angular velocity of the jth UAV in the target UAV group; S500: Obtain the second horizontal avoidance distance d between the i-th UAV and the j-th UAV in the target UAV group. 2 i,j ;d 2 i,j = ; S600: Obtain the target horizontal avoidance distance D between the i-th UAV and the j-th UAV in the target UAV group. i,j ;D i,j =min(d 1 i,j ,d 2 i,j ), min() is to find the minimum value; S700, obtain the target horizontal avoidance distance set D of the target UAV group, D={D1,D2,…,D k ,…,D q }, D k is the target horizontal avoidance distance of the kth drone pair in the target drone group, the value range of k is 1 to q, and q is the number of drone pairs that constitute the target drone group; S800, max(D) is determined as the horizontal avoidance distance between any two drones in the target drone group; max( ) is the maximum value; S200 includes: S210, obtaining the maximum turning angle θ of the i-th UAV in the target UAV group i ; S220, according to θ i Get the load factor LF of the i-th drone in the target drone group i ; S230, according to V i and LF i Get R i , R i =(V i ×V i ) / (g×((LF i ×LF i -1) 0.5 ) ’ ), where g is the acceleration due to gravity, ( ) ’ To seek guidance; LF i Satisfies the following relationship: LF i =1 / (cos(θ i )) ’ ; R j Satisfies the following relationship: R j =(V j ×V j ) / (g×((LF j ×LF j -1) 0.5 ) ’ ), where V j is the horizontal speed of the jth UAV in the target UAV group, LF j is the load factor of the jth UAV in the target UAV group, g is the gravitational acceleration, ( ) ’ To seek guidance; LF j Satisfies the following relationship: LF j =1 / (cos(θ j )) ’ ,θ j is the maximum turning angle of the jth UAV in the target UAV swarm.

2. The method for avoiding a swarm of drones according to claim 1, characterized in that: ω i Satisfies the following relationship: i =V i / R i .

3. The method for avoiding a swarm of drones according to claim 1, characterized in that: ω j Satisfies the following relationship: j =V j / R j , V j is the horizontal speed of the jth UAV in the target UAV swarm.

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