An unmanned aerial vehicle formation anti-collision method

Abstract

The application relates to a UAV formation anti-collision method, which comprises the following steps: step one, acquiring real-time surrounding situation information of a local machine, and performing horizontal and vertical collision detection on surrounding aircrafts to screen out invading aircrafts which may collide with the local machine; step two, sorting the invading aircrafts according to the threat degree of the invading aircrafts to the local machine; step three, judging the avoidance situation according to the relative position of the invading aircrafts and the local machine, selecting an avoidance strategy set of the local machine to the invading aircrafts from a strategy set according to avoidance principles, and obtaining an anti-collision strategy set T by comprehensively considering the avoidance strategy sets corresponding to the invading aircrafts; step four, solving a minimum strategy set T final executable from the anti-collision strategy set T final ; step five, if the minimum strategy set T final is not empty, the local machine executes a strategy in the minimum strategy set T final ; if the minimum strategy set T final is empty, the avoidance strategy set corresponding to the invading aircraft with the lowest threat degree to the local machine is removed from the anti-collision strategy set T, and steps four to five are re-performed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of unmanned aerial vehicle formation collision avoidance design, and particularly relates to an unmanned aerial vehicle formation collision avoidance method. BACKGROUND

[0002] With the development of unmanned aerial vehicle technology, air traffic is increasingly congested, and airspace itself is a limited resource. Under certain interval standards and air traffic control rules, unmanned aerial vehicles and civil aircraft share airspace, which is an inevitable trend.

[0003] Existing unmanned aerial vehicle collision avoidance technologies, such as artificial potential field method, geometric analysis method and probability-based prediction method, do not consider the case of sharing airspace with civil aircraft, so the algorithms are not compatible with civil flight guidelines, which leads to three problems. First, the unmanned aerial vehicle collision avoidance algorithm makes its behavior unpredictable, which makes it impossible for air traffic controllers to know the flight position of the unmanned aerial vehicle after starting collision avoidance, so they cannot guide civil aircraft to reasonably avoid. Second, the unmanned aerial vehicle is not controlled by a person on board, and the ground control station personnel intervene in the control of the unmanned aerial vehicle through a link. However, the ground control station personnel usually do not belong to the civil aviation system, so air traffic controllers cannot communicate with the ground control station personnel in time, which delays the time and increases the risk of collision between the unmanned aerial vehicle and the civil aircraft. Third, the data link between the ground control station and the unmanned aerial vehicle is unstable. If the unmanned aerial vehicle meets a civil aircraft and the data link fails, the unmanned aerial vehicle is uncontrollable, which can easily lead to serious consequences.

[0004] The present application is proposed in view of the above technical defects. SUMMARY

[0005] The purpose of the present application is to provide an unmanned aerial vehicle formation collision avoidance method to overcome or alleviate at least one aspect of the known technical defects.

[0006] The technical solution of the present application is:

[0007] An unmanned aerial vehicle formation collision avoidance method, comprising:

[0008] Step 1, real-time acquisition of the surrounding situation information of the machine, and horizontal and vertical collision detection of the surrounding aircraft to screen out invading aircraft that may collide with the machine;

[0009] Step 2, sorting according to the threat degree of the invading aircraft to the machine;

[0010] Step 3, judging the avoidance situation according to the relative position of the invading aircraft and the machine, selecting the avoidance strategy set of the machine to the invading aircraft from the strategy set according to the avoidance principle, and comprehensively obtaining the collision avoidance strategy set T corresponding to each invading aircraft;

[0011] Step 4: Find the minimum set of collision avoidance strategies T that can be executed. final ;

[0012] Minimal policy set T final Let T be the intersection of all avoidance strategy sets in the collision avoidance strategy set;

[0013] Step 5: If the minimum policy set T is... final If the value is not empty, then the local machine executes the minimum policy set T. final Mid-term strategy;

[0014] If the minimum strategy set T final If the value is empty, remove the avoidance strategy set corresponding to the intruding aircraft with the lowest threat level from the collision avoidance strategy set T, and repeat steps four and five.

[0015] Optionally, in the above-mentioned drone formation collision avoidance method, in step one:

[0016] Define aircraft A as the local aircraft, and treat it as stationary; and aircraft B as the surrounding aircraft.

[0017] In d min When R ≤ R, calculate the time T taken for machine B to reach the horizontal projection monitoring area of ​​machine A. au1 :

[0018]

[0019] in,

[0020] d min For machine A to distance, Let A and B be the relative velocities of machines A and B in the XY plane. and These are the components of the velocities of machines A and B in the XY plane.

[0021] AB is the distance between machine A and machine B, and θ is the oblique angle between machine A and machine B;

[0022] R is set to 50 km;

[0023] exist Calculate the time T taken for machine B to reach the vertical projection monitoring area of ​​machine A. au2 :

[0024]

[0025] in,

[0026] Let A and B be the relative velocities of the two machines on the YZ plane. and are the components of the velocity of the A and B aircraft in the Z axis direction;

[0027] are the directional vectors of the A and B aircraft;

[0028] If (T au1 <20)∩(T au2 <20), the B aircraft is considered to be an intruding aircraft that may collide with the A aircraft.

[0029] Optionally, in the unmanned aerial vehicle formation collision avoidance method described above, in step two:

[0030] Take the smaller value of T au1 , T au2 as the Tau value of the intruding aircraft, and the smaller the Tau value, the higher the threat to the aircraft.

[0031] Optionally, in the unmanned aerial vehicle formation collision avoidance method described above, in step three, the evasion strategy set includes strategy 0: turn right, strategy 1: turn left, strategy 2: descend, strategy 3: climb, strategy 4: decelerate, strategy 5: accelerate, strategy 6: decelerate, turn right, strategy 7: decelerate, turn left, strategy 8: decelerate, climb, strategy 9: decelerate, descend, strategy 10: accelerate, climb, strategy 11: accelerate, descend, strategy 12: climb, turn right, strategy 13: descend, turn right, strategy 14: climb, turn left, strategy 15: descend, turn left.

[0032] Optionally, in the unmanned aerial vehicle formation collision avoidance method described above, in step three, the evasion situation includes:

[0033] Evasion situation 1: the intruding aircraft and the aircraft meet head-on at the same height, -190°≤θ≤-170°, -260m≤Z≤260m, where θ is the difference between the heading angles of the intruding aircraft and the aircraft, and Z is the difference between the heights of the intruding aircraft and the aircraft. From the strategy set, the evasion strategy set of the aircraft for the intruding aircraft is selected as strategy 0, strategy 6, strategy 12, and strategy 13.

[0034] Evasion situation 2: the intruding aircraft and the aircraft meet in the same direction at the same height, the aircraft is behind, -10°≤θ≤10°, -260m≤Z≤260m, from the strategy set, the evasion strategy set of the aircraft for the intruding aircraft is selected as strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, and strategy 13.

[0035] Evasion situation 3: description: the intruding aircraft and the aircraft meet in front and back at the same height, the aircraft is in front, -10°≤θ≤10°, -260m≤Z≤260m, from the strategy set, the evasion strategy set of the aircraft for the intruding aircraft is selected as strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, and strategy 13.

[0036] Avoidance case 4: Intruder aircraft intersects with the host aircraft at the same height, -90°≤θ≤-10°, -260m≤Z≤260m, the velocity direction points to the host aircraft, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8;

[0037] Avoidance case 5: Intruder aircraft intersects with the host aircraft at the same height, -170°≤θ≤-90°, -260m≤Z≤260m, the velocity direction points to the host aircraft, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 1, strategy 3, strategy 14, strategy 10, strategy 7, strategy 8, strategy 12.

[0038] Optionally, in the unmanned aerial vehicle formation collision avoidance method described above, in step three, the avoidance case further includes:

[0039] Avoidance case 6: Description: Intruder aircraft intersects with the host aircraft at the same height, 10°≤θ≤90°, -260m≤Z≤260m, the velocity direction points to the host aircraft, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9;

[0040] Avoidance case 7: Intruder aircraft intersects with the host aircraft at the same height, -270°≤θ≤-190°, -260m≤Z≤260m, the velocity direction points to the host aircraft, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 0, strategy 2, strategy 13, strategy 6, strategy 9, strategy 11, strategy 15;

[0041] Avoidance case 8: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -180°≤θ≤0°, -260m≤Z≤260m, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9;

[0042] Avoidance case 9: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -90°≤θ≤-10°, Z≥260m, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 1, strategy 2, strategy 15, strategy 7, strategy 9, strategy 11;

[0043] Avoidance case 10: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -180°≤θ≤-90°, Z≥260m, from the strategy set, the host aircraft's avoidance strategy set for the intruder aircraft is strategy 0, strategy 2, strategy 6, strategy 9, strategy 13, strategy 11.

[0044] Optionally, in the unmanned aerial vehicle formation collision avoidance method, in step three, the avoidance situation further includes:

[0045] Avoidance situation 11: the intruding aircraft is above the host aircraft and the speed points to the host aircraft, -90°≤θ≤-10°, Z≥260m, the avoidance strategy set of the host aircraft to the intruding aircraft is selected from the strategy set as strategy 0, strategy 1, strategy 2, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9, strategy 11.

[0046] Avoidance situation 12: the intruding aircraft is above the host aircraft and the speed points to the host aircraft, -10°≤θ≤10°, 0°≤θ≤90°, Z≥260m, the avoidance strategy set of the host aircraft to the intruding aircraft is selected from the strategy set as strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8.

[0047] Avoidance situation 13: the intruding aircraft is above the host aircraft and the speed points to the host aircraft, -100°≤θ≤-80°, Z≥260m, the avoidance strategy set of the host aircraft to the intruding aircraft is selected from the strategy set as strategy 1, strategy 3, strategy 14, strategy 7, strategy 8, strategy 10.

[0048] Avoidance situation 14: the intruding aircraft is above the host aircraft and the speed points to the host aircraft, -270°≤θ≤-180°, Z≥260m, the avoidance strategy set of the host aircraft to the intruding aircraft is selected from the strategy set as strategy 0, strategy 3, strategy 12, strategy 6, strategy 8, strategy 10.

[0049] Avoidance situation 15: the intruding aircraft is above the host aircraft and the speed points to the host aircraft, -270°≤θ≤-190°, Z≥260m, the avoidance strategy set of the host aircraft to the intruding aircraft is selected from the strategy set as strategy 0, strategy 1, strategy 3, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8, strategy 10.

[0050] Optionally, in the unmanned aerial vehicle formation collision avoidance method, in step four, the minimum strategy set T final is the intersection of each avoidance strategy set in the collision avoidance strategy set T. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 is a schematic diagram of the unmanned aerial vehicle formation collision avoidance method provided by the embodiment of the application;

[0052] Figure 2 is a schematic diagram of the distance sphere model provided by the embodiment of the application;

[0053] Figure 3 is a schematic diagram of the time sphere model and its monitoring area provided by the embodiment of the application;

[0054] Figure 4 is a coordinate system definition schematic diagram provided by an embodiment of the present application;

[0055] Figure 5 is a schematic diagram of avoidance case 1 provided by an embodiment of the present application;

[0056] Figure 6 is a schematic diagram of avoidance case 2 provided by an embodiment of the present application;

[0057] Figure 7 is a schematic diagram of avoidance case 3 provided by an embodiment of the present application;

[0058] Figure 8 is a schematic diagram of avoidance case 4 provided by an embodiment of the present application;

[0059] Figure 9 is a schematic diagram of avoidance case 5 provided by an embodiment of the present application;

[0060] Figure 10 is a schematic diagram of avoidance case 6 provided by an embodiment of the present application;

[0061] Figure 11 is a schematic diagram of avoidance case 7 provided by an embodiment of the present application;

[0062] Figure 12 is a schematic diagram of avoidance case 8 provided by an embodiment of the present application;

[0063] Figure 13 is a schematic diagram of avoidance case 8 provided by an embodiment of the present application;

[0064] Figure 14 is a schematic diagram of avoidance case 9 provided by an embodiment of the present application;

[0065] Figure 15 is a schematic diagram of avoidance case 10 provided by an embodiment of the present application;

[0066] Figure 16 is a schematic diagram of avoidance case 11 provided by an embodiment of the present application;

[0067] Figure 17 is a schematic diagram of avoidance case 12 provided by an embodiment of the present application;

[0068] Figure 18 is a schematic diagram of avoidance case 12 provided by an embodiment of the present application;

[0069] Figure 19 is a schematic diagram of avoidance case 13 provided by an embodiment of the present application;

[0070] Figure 20 is a schematic diagram of avoidance case 14 provided by an embodiment of the present application;

[0071] Figure 21 FIG. 15 is a schematic diagram of the avoidance case 15 provided by the embodiment of the present application.

[0072] In order to better illustrate the embodiments, some components in the drawings can be omitted, enlarged or reduced, and do not represent the actual size of the product. In addition, the drawings are only used for illustrative description and cannot be understood as a limitation of the present application. DETAILED DESCRIPTION

[0073] In order to make the technical solutions of the present application and its advantages clearer, the technical solutions of the present application will be further clearly, completely and specifically described below with reference to the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, which are used to explain the present application, but not to limit the present application. It should be noted that, in order to facilitate the description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the general design.

[0074] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of the present application should be understood as the general meaning understood by the general technical personnel in the field of the present application. The words indicating the direction used in the description of the present application are only used to indicate the relative direction or positional relationship, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly. The "comprising" used in the description of the present application indicates that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, and other elements or objects are not excluded.

[0075] In addition, it should be further pointed out that, unless otherwise specified and limited, the "installation", "connection" and other similar words used in the description of the present application should be understood in a broad sense, for example, the connection can be fixed connection, or can be detachable connection; can be mechanical connection, or can be electrical connection; can be directly connected, or can be indirectly connected through intermediate medium, the skilled in the art can understand the specific meaning of the present application according to the specific circumstances.

[0076] A method for avoiding collisions in UAV formations mainly includes two parts: safety conflict detection and collision avoidance strategy design. The safety conflict detection defines a distance sphere model concept, a time sphere model based on a safety allowance time, and a monitoring zone concept. Horizontal and vertical safety conflict detection algorithms are designed based on the distance sphere and time sphere models. Once the collision avoidance conditions between the UAV and another aircraft are met, the collision avoidance strategy is activated. The collision avoidance strategy defines 15 scenarios based on the different positions and speed directions of the intruding aircraft relative to the UAV, covering all possible collision scenarios. Different strategy sets are designed for each scenario. All strategies are compatible with the "Basic Rules of Flight of the People's Republic of China." This method can address the need for simultaneous avoidance of UAVs and other aircraft in non-dense formations, making UAV avoidance actions predictable, meeting civil aviation standards, and reducing the safety risks of UAVs flying in the same airspace as civil aircraft.

[0077] A method for avoiding collisions in drone formations, such as Figure 1 As shown, it includes the following steps.

[0078] Step 1: Acquire real-time situational information about the surroundings of the aircraft and perform horizontal and vertical collision detection on the surrounding aircraft to screen out intruding aircraft that may collide with the aircraft.

[0079] Define a three-dimensional region with a radius of 150m centered on the local machine as a distance sphere, such as... Figure 2 As shown, the distance sphere represents the size of the machine. If another machine invades the distance sphere, it is considered that the other machine has collided with the machine.

[0080] Define Tau as the reserved time, which is the time required for the intruding aircraft to travel from the distance sphere to the local machine. Centered on the local machine, a three-dimensional area within Tau < 40s is designated as the warning zone, and a three-dimensional area within Tau < 20s is designated as the alert zone. This results in the time sphere, as follows: Figure 3 As shown.

[0081] Define the monitoring area as a three-dimensional spherical region with a radius of R = 50 km centered on the local machine. Figure 3 As shown, this aircraft only takes collision avoidance measures against intruding aircraft within the monitored area.

[0082] Establish a three-dimensional coordinate system with the machine as the center, with the positive X-axis pointing east, the positive Y-axis pointing north, and the positive Z-axis pointing to the sky. Figure 4 As shown.

[0083] Horizontal collision detection of surrounding aircraft is performed, as detailed below:

[0084] In the XY plane, aircraft A is considered stationary, while aircraft B represents surrounding aircraft, and the two are moving relative to each other at a certain speed. near:

[0085]

[0086] wherein,

[0087] and are the components of the velocity of the A and B aircraft in the XY plane.

[0088] define d min as the distance from the A aircraft to the B aircraft, if d min ≤ R, then a horizontal collision risk is considered and the time T au1 is calculated for the B aircraft to reach the horizontal projection monitoring area of the A aircraft.

[0089]

[0090] wherein,

[0091] AB is the distance between the A and B aircraft and θ is the oblique angle between the A and B aircraft.

[0092] The vertical collision detection is performed for the surrounding aircraft, and the following is specifically referred to:

[0093] On the YZ plane, the A aircraft is the own aircraft and is considered as static, and the B aircraft is the surrounding aircraft, and the two aircrafts approach with the relative motion velocity :

[0094]

[0095] wherein,

[0096] and are the components of the velocity of the A and B aircraft in the Z axis direction.

[0097] If the included angle of the vector is less than 90, wherein, is the direction vector of the A and B aircraft, then a vertical collision risk is considered and the time T au2 is calculated for the B aircraft to reach the vertical projection monitoring area of the A aircraft.

[0098]

[0099] If (T au1 <20)∩(T au2 <20), then the B aircraft is considered as the invading aircraft which is likely to collide with the A aircraft.

[0100] Step two, the invading aircrafts are sorted according to the threat degree to the own aircraft.

[0101] T au1 , T au2 ​The smaller the Tau value is, the higher the threat degree to the aircraft is.

[0102] Step three, according to the relative position of the invading aircraft and the aircraft, the avoidance situation is judged, and the avoidance strategy set of the aircraft to the invading aircraft is selected from the strategy set according to the avoidance principle, and the avoidance strategy set T is obtained by combining the avoidance strategy set corresponding to each invading aircraft.

[0103] The aircraft mainly changes the height (climb, descend), speed (accelerate, decelerate) and heading (left turn and right turn) to avoid collision, and the following avoidance strategy set is formed by combining the above three operations:

[0104] Strategy 0: right turn, strategy 1: left turn, strategy 2: descend, strategy 3: climb, strategy 4: decelerate, strategy 5: accelerate, strategy 6: decelerate, right turn, strategy 7: decelerate, left turn, strategy 8: decelerate, climb, strategy 9: decelerate, descend, strategy 10: accelerate, climb, strategy 11: accelerate, descend, strategy 12: climb, right turn, strategy 13: descend, right turn, strategy 14: climb, left turn, strategy 15: descend, left turn, as shown in the following table:

[0105]

[0106]

[0107] According to the quadrant where the invading aircraft is located and the speed direction, all possible scenarios of the unmanned aerial vehicle are classified, and the avoidance principle of each type of scene is formed based on the flight basic rules of the People's Republic of China as the design constraint. Based on the avoidance principle, a special strategy set is designed for each type of scene.

[0108] For each invading aircraft, according to its relative position with the aircraft, the invading aircraft is judged in the quadrant relative to the aircraft, and the speed of the invading aircraft and the speed of the aircraft are combined to form the avoidance strategy set Ti of the aircraft for each invading aircraft. If there are N invading aircrafts, the corresponding avoidance strategy set T = {T1, T2, … Tn}.

[0109] There are fifteen avoidance situations:

[0110] Avoidance situation 1:

[0111] Description: The invading aircraft meets the aircraft head-on at the same height, -190°≤θ≤-170°, -260m≤Z≤260m, where θ is the difference between the heading angle of the invading aircraft and the aircraft, and Z is the difference between the height of the invading aircraft and the aircraft, as shown in Figure 5

[0112] Avoidance principle: head-on encounter at the same height, right avoidance. ​

[0113] The avoidance strategy set of the intruder aircraft is selected from the strategy set as strategy 0, strategy 6, strategy 12, and strategy 13, as shown in the following table:

[0114] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 6 - √ - - - √ Strategy 12 - - √ - - √ Strategy 13 - - - √ - √

[0115] Avoidance case 2:

[0116] Description: The intruder aircraft and the host aircraft meet at the same height and in the same direction, the host aircraft is behind, -10°≤θ≤10°, -260m≤Z≤260m, as shown in the following figure: Figure 6

[0117] Avoidance principle: When meeting at the same height, the rear aircraft avoids to the right, climbs in height, the front aircraft avoids to the left, and descends in height.

[0118] The avoidance strategy set of the intruder aircraft is selected from the strategy set as strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, and strategy 13, as shown in the following table:

[0119] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 3 - - √ - - - Strategy 6 - √ - - - √ Strategy 8 - √ √ - - - Strategy 12 - - √ - - √ Strategy 13 - - - √ - √

[0120] Avoidance case 3:

[0121] Description: The intruder aircraft and the host aircraft meet at the same height and in the same direction, the host aircraft is in front, -10°≤θ≤10°, -260m≤Z≤260m, as shown in the following figure: Figure 7

[0122] Avoidance principle: When meeting at the same height, the rear aircraft avoids to the right, climbs in height, the front aircraft avoids to the left, and descends in height.

[0123] The avoidance strategy set of the intruder aircraft is selected from the strategy set as strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, and strategy 13, as shown in the following table:

[0124] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 1 - - - - √ - Strategy 2 - - - √ - - Strategy 11 √ - - √ - - Strategy 14 - - √ - √ - Strategy 15 - - - √ √ -

[0125] Avoidance case 4:

[0126] Description: The intruder aircraft and the host aircraft meet at the same height and cross each other, -90°≤θ≤-10°, -260m≤Z≤260m, the speed direction points to the host aircraft, as shown in the following figure: Figure 8

[0127] Avoidance principle: When meeting at the same height and crossing each other, the other aircraft is on the left side, the host aircraft descends in height, and the other aircraft is on the right side, the host aircraft climbs in height.

[0128] The avoidance strategy set of the intruder aircraft is selected from the strategy set as strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, and strategy 8, as shown in the following table:​​​

[0129] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 1 - - - - √ - Strategy 3 - - √ - - - Strategy 10 √ - √ - - - Strategy 12 - - √ - - √ Strategy 14 - - √ - √ - Strategy 6 - √ - - - √ Strategy 7 - √ - - √ - Strategy 8 - √ √ - - -

[0130] Avoidance situation 5:

[0131] Description: Invading aircraft and the native same height cross encounter, -170°≤θ≤-90°, -260m≤Z≤260m, the direction of velocity points to the native, as shown in Figure 9 .

[0132] Avoidance principle: Cross encounter at the same height, the other aircraft on the left, the native reduces height, the other aircraft on the right, the native climbs height.

[0133] From the strategy set, the native evasive strategy set for the invading aircraft is strategy 1, strategy 3, strategy 14, strategy 10, strategy 7, strategy 8, strategy 12, as shown in the following table:

[0134] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 1 - - - - √ - Strategy 3 - - √ - - - Strategy 14 - - √ - √ - Strategy 10 √ - √ - - - Strategy 7 - √ - - √ - Strategy 8 - √ √ - - - Strategy 12 - - √ - - √

[0135] Avoidance situation 6:

[0136] Description: Invading aircraft and the native same height cross encounter, 10°≤θ≤90°, -260m≤Z≤260m, the direction of velocity points to the native, as shown in Figure 10 .

[0137] Avoidance principle: Cross encounter at the same height, the other aircraft on the left, the native reduces height, the other aircraft on the right, the native climbs height.

[0138] From the strategy set, the native evasive strategy set for the invading aircraft is strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9, as shown in the following table:

[0139] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 1 - - - - √ - Strategy 2 - - - √ - - Strategy 11 √ - - √ - - Strategy 13 - - - √ - √ Strategy 15 - - - √ √ - Strategy 6 - √ - - - √ Strategy 7 - √ - - √ - Strategy 9 - √ - √ - -

[0140] Avoidance situation 7:

[0141] Description: Invading aircraft and the native same height cross encounter, -270°≤θ≤-190°, -260m≤Z≤260m, the direction of velocity points to the native, as shown in Figure 11 .

[0142] Avoidance principle: Cross encounter at the same height, the other aircraft on the left, the native reduces height, the other aircraft on the right, the native climbs height.

[0143] From the strategy set, the native evasive strategy set for the invading aircraft is strategy 0, strategy 2, strategy 13, strategy 6, strategy 9, strategy 11, strategy 15, as shown in the following table:

[0144] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 2 - - - √ - - Strategy 13 - - - √ - √ Strategy 6 - √ - - - √ Strategy 9 - √ - √ - - Strategy 11 √ - - √ - - Strategy 15 - - - √ √ -

[0145] Avoidance case 8:

[0146] Description: The intruder aircraft is above the own aircraft and the velocity points to the own aircraft, -180°≤θ≤0°, -260m≤Z≤260m, as shown in Figure 12 13 .

[0147] Avoidance principle: Cross each other at different altitudes, the low-altitude aircraft does not climb, and the high-altitude aircraft does not descend.

[0148] From the strategy set, the avoidance strategy set of the own aircraft to the intruder aircraft is selected as strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9, as shown in the following table:

[0149] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 1 - - - - √ - Strategy 2 - - - √ - - Strategy 11 √ - - √ - - Strategy 13 - - - √ - √ Strategy 15 - - - √ √ - Strategy 6 - √ - - - √ Strategy 7 - √ - - √ - Strategy 9 - √ - √ - -

[0150] Avoidance case 9:

[0151] Description: The intruder aircraft is above the own aircraft and the velocity points to the own aircraft, -90°≤θ≤-10°, Z≥260m, as shown in Figure 14 .

[0152] Avoidance principle: Cross each other at different altitudes, the low-altitude aircraft does not climb, and the high-altitude aircraft does not descend.

[0153] From the strategy set, the avoidance strategy set of the own aircraft to the intruder aircraft is selected as strategy 1, strategy 2, strategy 15, strategy 7, strategy 9, strategy 11, as shown in the following table:

[0154] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 1 - - - - √ - Strategy 2 - - - √ - - Strategy 15 - - - √ √ - Strategy 7 - √ - - √ - Strategy 9 - √ - √ - - Strategy 11 √ - - √ - -

[0155] Avoidance case 10:

[0156] Description: The intruder aircraft is above the own aircraft and the velocity points to the own aircraft, -180°≤θ≤-90°, Z≥260m, as shown in Figure 15 .

[0157] Avoidance principle: Cross each other at different altitudes, the low-altitude aircraft does not climb, and the high-altitude aircraft does not descend.

[0158] From the strategy set, the avoidance strategy set of the own aircraft to the intruder aircraft is selected as strategy 0, strategy 2, strategy 6, strategy 9, strategy 13, strategy 11, as shown in the following table:

[0159] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 2 - - - √ - - Strategy 6 - √ - - - √ Strategy 9 - √ - √ - - Strategy 13 - - - √ - √ Strategy 11 √ - - √ - -

[0160] Avoidance case 11:

[0161] ​Description: Intruder aircraft is above the host aircraft, and the speed points to the host aircraft, -90°≤θ≤-10°, Z≥260m, as shown in Figure 16

[0162] Avoidance principle: cross each other at different altitudes, low-altitude aircraft do not climb, high-altitude aircraft do not descend.

[0163] From the strategy set, the host aircraft's evasion strategy set for the intruder aircraft is strategy 0, strategy 1, strategy 2, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9, strategy 11, as shown in the following table:

[0164] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 1 - - - - √ - Strategy 2 - - - √ - - Strategy 13 - - - √ - √ Strategy 15 - - - √ √ - Strategy 6 - √ - - - √ Strategy 7 - √ - - √ - Strategy 9 - √ - √ - - Strategy 11 √ - - √ - -

[0165] Avoidance case 12:

[0166] Description: Intruder aircraft is above the host aircraft, and the speed points to the host aircraft, -10°≤θ≤10°, 0°≤θ≤90°, Z≥260m, as shown in Figure 17 、 18 .

[0167] Avoidance principle: cross each other at different altitudes, low-altitude aircraft do not climb, high-altitude aircraft do not descend.

[0168] From the strategy set, the host aircraft's evasion strategy set for the intruder aircraft is strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8, as shown in the following table:

[0169] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 1 - - - - √ - Strategy 3 - - √ - - - Strategy 10 √ - √ - - - Strategy 12 - - √ - - √ Strategy 14 - - √ - √ - Strategy 6 - √ - - - √ Strategy 7 - √ - - √ - Strategy 8 - √ √ - - -

[0170] Avoidance case 13:

[0171] Description: Intruder aircraft is above the host aircraft, and the speed points to the host aircraft, -100°≤θ≤-80°, Z≥260m, as shown in Figure 19 .

[0172] Avoidance principle: cross each other at different altitudes, low-altitude aircraft do not climb, high-altitude aircraft do not descend.

[0173] From the strategy set, the host aircraft's evasion strategy set for the intruder aircraft is strategy 1, strategy 3, strategy 14, strategy 7, strategy 8, strategy 10, as shown in the following table:

[0174]

[0175]

[0176] Avoidance case 14:

[0177] ​Description: The intruder aircraft is above the own aircraft, and the speed points to the own aircraft, -270°≤θ≤-180°, Z≥260m, as shown in Figure 20

[0178] Avoidance principle: cross each other at different altitudes, the low-altitude aircraft does not climb, and the high-altitude aircraft does not descend.

[0179] The avoidance strategy set of the own aircraft to the intruder aircraft is selected from the strategy set as strategy 0, strategy 3, strategy 12, strategy 6, strategy 8, and strategy 10, as shown in the following table:

[0180] Accelerate Decelerate Climb Descend Left turn Right turn Strategy 0 - - - - - √ Strategy 3 - - √ - - - Strategy 12 - - √ - - √ Strategy 6 - √ - - - √ Strategy 8 - √ √ - - - Strategy 10 √ - √ - - -

[0181] Avoidance case 15:

[0182] Description: The intruder aircraft is above the own aircraft, and the speed points to the own aircraft, -270°≤θ≤-190°, Z≥260m, as shown in Figure 21

[0183] Avoidance principle: cross each other at different altitudes, the low-altitude aircraft does not climb, and the high-altitude aircraft does not descend.

[0184] The avoidance strategy set of the own aircraft to the intruder aircraft is selected from the strategy set as strategy 0, strategy 1, strategy 3, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8, and strategy 10, as shown in the following table:

[0185]

[0186]

[0187] Step four, solving the minimum strategy set T final .

[0188] The minimum strategy set T final is the intersection of each avoidance strategy set in the collision avoidance strategy set T.

[0189] Step five, if the minimum strategy set T final is not empty, the own aircraft executes the strategy in the minimum strategy set T final .

[0190] If the minimum strategy set T final is empty, the avoidance strategy set corresponding to the intruder aircraft with the lowest threat degree to the own aircraft is removed from the collision avoidance strategy set T, and steps four to five are performed again.

[0191] ​​The unmanned aerial vehicle formation anti-collision method disclosed in the above embodiments classifies all situations in which the unmanned aerial vehicle may encounter invading aircraft, and designs anti-collision rules based on the Basic Rules of Flight of the People's Republic of China for each category, so that the unmanned aerial vehicle can avoid both the same aircraft in the formation and the civil aircraft, the evasive behavior of the unmanned aerial vehicle in uncontrolled situations is predictable, and is compatible with the flight rules of civil aircraft, which reduces the safety hazard of collision between the two aircraft, improves the utilization rate of limited airspace resources, and makes the existing air traffic management system meet the needs of manned and unmanned development, and greatly improves the efficiency of air transportation.

[0192] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, and those skilled in the art should understand that the protection scope of the present application is obviously not limited to these specific embodiments, and those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solutions after these changes or replacements will fall within the protection scope of the present application.

Claims

1. A method for collision avoidance of unmanned aerial vehicle formation, characterized in that, Comprise: Step one, real-time acquisition of the situation information around the native, and the surrounding aircraft for horizontal and vertical conflict detection, screening out the possible with the native invasion aircraft collision; Step two, according to the threat degree of the invasion aircraft to the native, sorting; Step three, according to the relative position of the invasion aircraft and the native, to judge the avoidance situation, according to the avoidance principle, from the strategy set, the native to the invasion aircraft avoidance strategy set, comprehensive corresponding to each invasion aircraft avoidance strategy set, get the anti-collision strategy set T; Step four, solving the minimum strategy set T executable by the anti-collision strategy set T final ; Step five, if the minimum strategy set T final is not empty, then the local executes the minimum strategy set T final strategy in T If the minimum strategy set T final is empty, the avoidance strategy set corresponding to the intruder aircraft with the lowest threat level to the host aircraft is removed from the collision avoidance strategy set T, and steps four to five are repeated. Step one: Define A machine as the native, as static, B machine as the surrounding aircraft; In d min When R≤Rth, calculate the time T that the B machine reaches the horizontal projection monitoring area of the A machine au1 : Wherein, d min is the distance from A to is the distance from A to is the relative velocity of A and B in XY plane; and is the component of A and B velocity in XY plane; AB is the distance between A machine and B machine, θ is the angle between A machine and B machine; R is 50Km; In case the B machine reaches the vertical projection monitoring area of the A machine, the time T au2 : Wherein, for YZ plane, relative motion speed of A machine, B machine; and for A machine and B machine speed in the direction of the Z axis component; are the direction vectors of the A and B machines; If (T au1 <20)∩(T au2 <20), the B machine is considered as an intruding aircraft that may collide with the A machine.

2. The unmanned aerial vehicle formation collision avoidance method according to claim 1, wherein, Step two: Take T au1 , T au2 The smaller value as the number of intruding aircraft Tau value, the smaller the Tau value, the higher the threat to the home.

3. The unmanned aerial vehicle formation collision avoidance method according to claim 2, wherein, Step three, avoidance strategy set includes strategy 0: right turn, strategy 1: left turn, strategy 2: descent, strategy 3: climb, strategy 4: deceleration, strategy 5: acceleration, strategy 6: deceleration, right turn, strategy 7: deceleration, left turn, strategy 8: deceleration, climb, strategy 9: deceleration, descent, strategy 10: acceleration, climb, strategy 11: acceleration, descent, strategy 12: climb, right turn, strategy 13: descent, right turn, strategy 14: climb, left turn, strategy 15: descent, left turn.

4. The unmanned aerial vehicle formation collision avoidance method according to claim 3, wherein, Step three, avoidance situation includes: Avoidance situation 1: the invasion aircraft and the native meet head-on at the same height, -190°≤θ≤-170°, -260m≤Z≤260m, wherein, θ is the difference between the heading angle of the invasion aircraft and the native, Z is the difference between the height of the invasion aircraft and the native, the avoidance strategy set of the native to the invasion aircraft is selected from the strategy set, strategy 0, strategy 6, strategy 12, strategy 13; Avoidance situation 2: the invasion aircraft and the native meet in the same direction at the same height, the native is behind, -10°≤θ≤10°, -260m≤Z≤260m, the avoidance strategy set of the native to the invasion aircraft is selected from the strategy set, strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, strategy 13; Avoidance situation 3: description: the invasion aircraft and the native meet in front and back at the same height, the native is in front, -10°≤θ≤10°, -260m≤Z≤260m, the avoidance strategy set of the native to the invasion aircraft is selected from the strategy set, strategy 0, strategy 3, strategy 6, strategy 8, strategy 12, strategy 13; Avoidance situation 4: the invasion aircraft and the native meet at the same height, -90°≤θ≤-10°, -260m≤Z≤260m, the speed direction points to the native, the avoidance strategy set of the native to the invasion aircraft is selected from the strategy set, strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8; Evasion case 5: Intruder aircraft intersects with the host aircraft at the same height, -170°≤θ≤-90°, -260m≤Z≤260m, the velocity direction points to the host aircraft, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 1, strategy 3, strategy 14, strategy 10, strategy 7, strategy 8, strategy 12.

5. The unmanned aerial vehicle formation collision avoidance method according to claim 4, wherein, In step three, the evasion case further includes: Evasion case 6: Description: Intruder aircraft intersects with the host aircraft at the same height, 10°≤θ≤90°, -260m≤Z≤260m, the velocity direction points to the host aircraft, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9; Evasion case 7: Intruder aircraft intersects with the host aircraft at the same height, -270°≤θ≤-190°, -260m≤Z≤260m, the velocity direction points to the host aircraft, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 2, strategy 13, strategy 6, strategy 9, strategy 11, strategy 15; Evasion case 8: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -180°≤θ≤0°, -260m≤Z≤260m, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 1, strategy 2, strategy 11, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9; Evasion case 9: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -90°≤θ≤-10°, Z≥260m, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 1, strategy 2, strategy 15, strategy 7, strategy 9, strategy 11; Evasion case 10: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -180°≤θ≤-90°, Z≥260m, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 2, strategy 6, strategy 9, strategy 13, strategy 11.

6. The unmanned aerial vehicle formation collision avoidance method according to claim 5, wherein, In step three, the evasion case further includes: Evasion case 11: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -90°≤θ≤-10°, Z≥260m, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 1, strategy 2, strategy 13, strategy 15, strategy 6, strategy 7, strategy 9, strategy 11; Evasion case 12: Intruder aircraft is above the host aircraft, and the velocity direction points to the host aircraft, -10°≤θ≤10°, 0°≤θ≤90°, Z≥260m, the host aircraft selects the evasion strategy set from the whole strategy set as strategy 0, strategy 1, strategy 3, strategy 10, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8; Avoidance case 13: the invading aircraft is above the host aircraft and the speed points to the host aircraft, -100°≤θ≤-80°, Z≥260m, the evasion strategy set of the host aircraft to the invading aircraft is selected from the whole strategy set as strategy 1, strategy 3, strategy 14, strategy 7, strategy 8, strategy 10; Avoidance case 14: the invading aircraft is above the host aircraft and the speed points to the host aircraft, -270°≤θ≤-180°, Z≥260m, the evasion strategy set of the host aircraft to the invading aircraft is selected from the whole strategy set as strategy 0, strategy 3, strategy 12, strategy 6, strategy 8, strategy 10; Avoidance case 15: the invading aircraft is above the host aircraft and the speed points to the host aircraft, -270°≤θ≤-190°, Z≥260m, the evasion strategy set of the host aircraft to the invading aircraft is selected from the whole strategy set as strategy 0, strategy 1, strategy 3, strategy 12, strategy 14, strategy 6, strategy 7, strategy 8, strategy 10.

7. The unmanned aerial vehicle formation collision avoidance method according to claim 6, characterized in that, In step four, the minimum strategy set T final The intersection of each evasive strategy set in the collision avoidance strategy set T.

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