Method for resolving multi-UAV dynamic conflict based on speed or heading allocation

Abstract

The present invention relates to a method for dynamic conflict resolution of unmanned aerial vehicles (UAVs) based on speed or heading allocation, belonging to the technical field of UAVs, and solves the problems that the existing obstacle avoidance method based on the speed obstacle method cannot achieve multi-aircraft dynamic conflict resolution and has poor obstacle avoidance safety. The method of the present invention includes: detecting whether there are potential collision aircraft in the current airspace; if multiple potential collision aircraft are detected, for each potential collision aircraft, single-aircraft conflict resolution calculation is respectively performed based on the maneuverability parameters of the UAV; comparing all the single-aircraft conflict resolution calculation results, selecting the speed adjustment method or rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle, and selecting the actual allocation parameters according to the maximum principle; the UAV adjusts its speed or heading according to the obtained speed adjustment method or rotation direction for multi-aircraft conflict resolution and the corresponding allocation parameters. The method of the present invention can solve the multi-aircraft dynamic conflict problem and improve the obstacle avoidance safety and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and particularly to a method for relieving multi-aircraft dynamic conflicts of unmanned aerial vehicles based on speed or heading allocation. Background Art

[0002] With the wide application of unmanned aerial vehicle systems in multiple fields such as industry, agriculture, and military, it has become a current trend for unmanned aerial vehicles to fly out of the "isolated airspace" and share the airspace with manned aircraft to perform diverse tasks. The key technology restricting the full-range flight of unmanned aerial vehicles is the reliable flight conflict relief ability. Different from manned aircraft, which mainly rely on flight conflict relief methods such as air traffic management and air collision avoidance systems, unmanned aerial vehicles have significant differences in conflict relief technology due to characteristics such as long command operation delay time, relatively small payload, complex dynamic models, and high uncertainty of threats faced. To ensure the reliability of obstacle avoidance performance, continuous changes in the state of unmanned aerial vehicles should be avoided as much as possible, and collision avoidance and task execution functions should be achieved on the basis of minimal maneuvering, which is convenient for operation and ensures flight safety.

[0003] In the prior art, most of the multi-aircraft dynamic conflict relief methods adopt obstacle avoidance methods based on machine learning. However, when the flight scenario changes, the obstacle avoidance accuracy of such methods decreases, and the model needs to be retrained. The offline learning and training of the model takes a long time and is not easy to converge, and the cost is relatively high.

[0004] In the prior art, the obstacle avoidance method based on the velocity obstacle method has achieved good results in the field of single-aircraft conflicts. The velocity obstacle method calculates the closest distance between each other during the movement process through the relative velocity between the two to determine whether there is a flight conflict between the unmanned aerial vehicle and the obstacle. For the obstacle avoidance method based on the velocity obstacle method, after determining the existence of a potential conflict, it is generally relieved by heading allocation or speed allocation. This method has low computational complexity, good real-time performance, and high obstacle avoidance accuracy. However, most of the existing obstacle avoidance methods based on the velocity obstacle method are used to solve single-aircraft conflict problems, and there is less research on multi-aircraft conflict problems. Specifically, the existing obstacle avoidance methods based on the velocity obstacle method focus on solving the optimal speed or optimal heading for unmanned aerial vehicle obstacle avoidance, and do not give specific strategies on how to plan the speed or heading allocation parameters for unmanned aerial vehicles to avoid multiple aircraft at the same time.

[0005] In addition, in the existing obstacle avoidance methods based on the velocity obstacle method, the actual maneuverability constraints of unmanned aerial vehicles are not considered, that is, it is not considered that the speed and heading adjustment of unmanned aerial vehicles is a gradual process. Specifically, for example, the speed of an unmanned aerial vehicle cannot immediately jump from 10 m / s to 20 m / s, resulting in the fact that the unmanned aerial vehicle cannot actually reach the planned relief point position, which generates an unpredictable risk to the relief effect, has poor obstacle avoidance safety, and makes the unmanned aerial vehicle unable to continue to perform tasks. Summary of the Invention

[0006] In view of the above analysis, the embodiments of the present invention aim to provide a method for multi - drone dynamic conflict resolution based on speed or heading allocation, which is used to solve the technical problems that the existing obstacle avoidance method based on the speed obstacle method cannot enable drones to achieve multi - drone dynamic conflict resolution, and the technical problem that the obstacle avoidance safety is poor due to the lack of consideration of the maneuverability constraints of drones during the resolution calculation.

[0007] On the one hand, the embodiments of the present invention provide a method for multi - drone dynamic conflict resolution based on speed allocation, and the method includes:

[0008] When a drone executes a flight mission, based on the speed obstacle method, detect whether there are potential collision aircraft in the current airspace that have a potential collision risk with the drone;

[0009] If multiple potential collision aircraft are detected, for each potential collision aircraft, respectively perform single - aircraft conflict resolution calculation based on the maneuverability parameters of the drone to obtain the speed adjustment method and the corresponding allocation parameters for which the drone can successfully resolve the conflict with each potential collision aircraft; the maneuverability parameters include the maximum longitudinal acceleration, the minimum longitudinal speed, and the maximum longitudinal speed; the speed adjustment methods include acceleration methods and deceleration methods; the allocation parameters include the obstacle avoidance flight distance and the speed adjustment amount;

[0010] Compare the single - aircraft conflict resolution calculation results of all potential collision aircraft, select a speed adjustment method as the speed adjustment method for multi - aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual allocation parameters from the allocation parameters corresponding to the speed adjustment method for multi - aircraft conflict resolution according to the maximum principle;

[0011] The drone adjusts its speed to the obstacle avoidance flight speed at the maximum longitudinal acceleration according to the obtained speed adjustment method for multi - aircraft conflict resolution and the actual speed adjustment amount, and then the drone flies at a constant speed at the obstacle avoidance speed until the flight distance of the drone reaches the actual obstacle avoidance flight distance, so as to achieve multi - drone dynamic conflict resolution.

[0012] Based on a further improvement of the above method, the method for performing single - aircraft conflict resolution calculation based on the maneuverability parameters of the drone is as follows:

[0013] Define the initial position of the drone as A and the initial speed as V A_0 ; the initial position of the target aircraft is O, the safety circle radius is R, and the flight speed is V 0 ; the initial distance between the drone and the target aircraft is L AO ;

[0014] According to the relative velocity vector between the drone and the target aircraft and the safety circle of the target aircraft, determine the position B of the release point corresponding to the acceleration method and the position C of the release point corresponding to the deceleration method;

[0015] Calculate the obstacle avoidance flight distance L of the UAV corresponding to the acceleration mode and the deceleration mode according to the following formula AD and the required obstacle avoidance flight time T to reach the obstacle avoidance flight distance L AD : total :

[0016] ||V A_1 || = ||-V 0 || · (sinα / sinβ);

[0017] ||V R_1 || = ||-V 0 || · (sin(α + β) / sinβ);

[0018]

[0019] T total = L AD / ||V A_1 ||;

[0020] In the formula, is the relative velocity vector of the UAV avoiding the target aircraft. In the acceleration mode In the deceleration mode, α is the angle between -V 0 and ; V A_1 is the speed that can achieve conflict resolution when it is assumed that the UAV can instantaneously change its speed. V A_1 has the same direction as V A_0 ; β is the angle between V A_1 and ; V R_1 is the relative velocity vector of V A_1 and V 0 , V R_1 = V A_1 -V 0 ;

[0021] Judge whether the UAV can successfully resolve the conflict through the acceleration mode or the deceleration mode respectively according to the obstacle avoidance flight distance L AD of the UAV, the obstacle avoidance flight time T total and the maneuverability parameters of the UAV. The formula is:

[0022]

[0023]

[0024]

[0025] In the formula, V A_max and VA_min are the maximum longitudinal velocity and minimum longitudinal velocity of the UAV, V A_max >V A_min >0;V A_limit is the speed limit of the drone; L max The maximum distance that the drone can actually fly; T min is the minimum time required for the drone to reach the speed limit; a is the acceleration of the drone, and in the acceleration mode a=a max , in the deceleration mode, a=-a max ;

[0026] If L max <L AD , then it cannot be successfully liberated; if L max ≥L AD , then you can be liberated successfully;

[0027] If the escape is successful, then according to the obstacle avoidance flight distance L AD , the obstacle avoidance flight time T total Calculate the speed adjustment ΔV of the drone A_1 , the drone accelerates to the obstacle avoidance speed V A_0 +ΔV A_1 The time required T 1 and the drone flies at obstacle avoidance speed V A_0 +ΔV A_1 The time of uniform flight T 2 , the formula is:

[0028] L AD =V A_0 ·T 1 +(a·T 1 2 ) / 2+(V A_0 +a·T 1 )·(T total -T 1 );

[0029] ΔV A_1 =a·T 1 ;

[0030] T 2 =T total -T 1 .

[0031] Based on the further improvement of the above method, the method of selecting a speed regulation mode as the speed regulation mode for multi-machine conflict resolution according to the consistency principle and the safety principle includes:

[0032] After comparing the single - aircraft conflict resolution calculation results of all potential collision aircraft, if only one speed - adjustment method can successfully resolve the conflict between the UAV and all potential collision aircraft, then select this speed - adjustment method as the speed - adjustment method for multi - aircraft conflict resolution;

[0033] After comparing the single - aircraft conflict resolution calculation results of all potential collision aircraft, if two speed - adjustment methods can both successfully resolve the conflict between the UAV and all potential collision aircraft, then judge the safer speed - adjustment method for the UAV with respect to this potential collision aircraft according to the relative position between the relative velocity vector of the UAV and the potential aircraft and the safety circle of this potential collision aircraft, and take it as the preferred speed - adjustment method;

[0034] Compare the preferred speed - adjustment methods of the UAV for each potential collision aircraft, and select a speed - adjustment method from the preferred speed - adjustment methods as the speed - adjustment method for multi - aircraft conflict resolution according to the consistency principle and the safety principle. Based on a further improvement of the above method, the step of comparing the preferred speed - adjustment methods of the UAV for each potential collision aircraft and selecting a speed - adjustment method from the preferred speed - adjustment methods as the speed - adjustment method for multi - aircraft conflict resolution according to the consistency principle and the safety principle includes:

[0035] If the preferred speed - adjustment methods of the UAV for each potential collision aircraft are the same, then select the preferred speed - adjustment method as the speed - adjustment method for multi - aircraft conflict resolution;

[0036] If the preferred speed - adjustment methods of the UAV for each potential collision aircraft are not the same, then compare the longest obstacle - avoidance flight times corresponding to the two speed - adjustment methods, and select the speed - adjustment method corresponding to the smaller value according to the safety principle as the speed - adjustment method for multi - aircraft conflict resolution.

[0037] Based on a further improvement of the above method, the step of comparing the preferred speed - adjustment methods of the UAV for each potential collision aircraft and selecting a speed - adjustment method from the preferred speed - adjustment methods as the speed - adjustment method for multi - aircraft conflict resolution according to the consistency principle and the safety principle includes:

[0038] If the preferred speed - adjustment methods of the UAV for each potential collision aircraft are the same, then select the preferred speed - adjustment method as the speed - adjustment method for multi - aircraft conflict resolution;

[0039] If the preferred speed - adjustment methods of the UAV for each potential collision aircraft are not the same, then for each potential collision aircraft, calculate the distance between the UAV and this potential collision aircraft at a preset moment during the obstacle - avoidance flight process based on the acceleration method and the deceleration method respectively, and take it as the dangerous distance; the preset moment is the moment when the relative velocity vector of the UAV and this potential collision aircraft points to the center point of this potential collision aircraft;

[0040] Compare the dangerous distances between the UAV corresponding to the acceleration method and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance of the acceleration method; compare the dangerous distances between the UAV corresponding to the deceleration method and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance of the deceleration method;

[0041] Compare the minimum dangerous distance of the acceleration method and the minimum dangerous distance of the deceleration method, and select the speed regulation method corresponding to the larger value based on the safety principle as the speed regulation method for multi-aircraft conflict resolution.

[0042] On the other hand, an embodiment of the present invention provides a method for multi-aircraft dynamic conflict resolution of UAVs based on heading allocation, and the method includes:

[0043] When the UAV executes a flight mission, detect whether there are potential collision aircraft in the current airspace that have a potential collision risk with the UAV based on the velocity obstacle method;

[0044] If multiple potential collision aircraft are detected, for each potential collision aircraft, perform single-aircraft conflict resolution calculation based on the maneuverability parameters of the UAV to obtain the rotation direction in which the UAV can successfully resolve the conflict with each potential collision aircraft and the corresponding allocation parameters; the maneuverability parameters include the maximum angular velocity; the rotation directions include counterclockwise and clockwise; the allocation parameters include the obstacle avoidance flight distance and the rotation angle;

[0045] Compare the single-aircraft conflict resolution calculation results of all potential collision aircraft, select a rotation direction as the rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual allocation parameters from the allocation parameters corresponding to the rotation direction of the multi-aircraft conflict resolution according to the principle of taking the larger value;

[0046] The UAV adjusts its heading at the maximum angular velocity in the rotation direction and actual rotation angle obtained for multi-aircraft conflict resolution, and maintains a constant speed flight at the initial speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, thereby realizing multi-aircraft dynamic conflict resolution.

[0047] Based on a further improvement of the above method, the method for performing single-aircraft conflict resolution calculation based on the maneuverability parameters of the UAV is as follows:

[0048] Define the initial position of the UAV as A and the initial velocity as V A_0 ; the initial position of the target aircraft is O, the safety circle radius is R, and the flight speed is V 0 ; the initial distance between the UAV and the target aircraft is L AO ;

[0049] Determine the release point position B' corresponding to the counterclockwise direction and the release point position C' corresponding to the clockwise direction according to the relative velocity vector of the UAV and the target aircraft and the safety circle of the target aircraft;

[0050] Calculate the rotation angle θ of the UAV and the obstacle avoidance flight distance L corresponding to the counterclockwise direction and the clockwise direction according to the following formula AD and the obstacle avoidance flight distance L is reached AD The required obstacle avoidance flight time T' total , the formula is:

[0051] ||V A_2 || / sinα = ||-V 0 || / sinδ;

[0052] ||V A_2 || = ||V A_0 ||;

[0053] V R_2 = V A_2 -V 0 ;

[0054] δ = arcsin(||-V 0 ||·sinα / ||V A_2 ||);

[0055] θ = δ - β;

[0056]

[0057] L AD = ||V A_0 ||·T' total ;

[0058] In the formula, V A_2 is the velocity vector after the rotation angle θ of the UAV; V R_2 is the relative velocity vector between the UAV and the target aircraft after the rotation angle θ of the UAV; The relative velocity vector of the UAV avoiding potential aircraft, when rotating counterclockwise when rotating clockwise, α is the angle between -V 0 and ; β is the angle between the velocity vector V A_0 and the vector ; δ is the angle between the velocity vector V A_2 and V R_2 ; when the UAV rotates counterclockwise, 0 < θ < 90°; when the UAV rotates clockwise, -90° < θ < 0;

[0059] Obtain the rotation angle θ of the UAV and the obstacle avoidance flight time T' of the UAVtotal After that, it is determined whether the UAV can successfully disengage by rotating counterclockwise or clockwise according to the maximum angular velocity ω of the UAV.

[0060] If θ ≤ ω·T' total , the UAV can successfully disengage. If θ > ω·T' total , the UAV cannot successfully disengage.

[0061] Based on the further improvement of the above method, the selection of a rotation direction as the rotation direction for multi-UAV conflict disengagement according to the consistency principle and the safety principle includes:

[0062] After comparing the single-UAV conflict disengagement calculation results of all potential collision UAVs, if only one rotation direction can enable the UAV to successfully disengage from all potential collision UAVs, then select this rotation direction as the rotation direction for multi-UAV conflict disengagement;

[0063] After comparing the single-UAV conflict disengagement calculation results obtained by all potential collision UAVs, if both rotation directions can enable the UAV to successfully disengage from all potential collision UAVs, then judge the safer rotation direction of the UAV for this potential collision UAV according to the relative position of the relative velocity vector of the UAV and the potential UAV to the safety circle of this potential collision UAV, and use it as the preferred rotation direction;

[0064] Compare the preferred rotation directions of the UAV for each potential collision UAV, and select a rotation direction from the preferred rotation directions as the rotation direction for multi-UAV conflict disengagement according to the consistency principle and the safety principle. Based on the further improvement of the above method, the comparison of the preferred rotation directions of the UAV for each potential collision UAV, and the selection of a rotation direction from the preferred rotation directions as the rotation direction for multi-UAV conflict disengagement according to the consistency principle and the safety principle includes:

[0065] If the preferred rotation directions of the UAV for each potential collision UAV are the same, then select the preferred rotation direction as the rotation direction for multi-UAV conflict disengagement;

[0066] If the preferred rotation directions of the UAV for each potential collision UAV are not the same, then compare the longest obstacle avoidance flight times corresponding to the two rotation directions, and select the rotation direction corresponding to the smaller value according to the safety principle as the rotation direction for multi-UAV conflict disengagement.

[0067] Based on the further improvement of the above method, the comparison of the preferred rotation directions of the UAV for each potential collision UAV, and the selection of a rotation direction from the preferred rotation directions as the rotation direction for multi-UAV conflict disengagement according to the consistency principle and the safety principle includes:

[0068] If the preferred rotation directions of the UAV with respect to all potential collision aircraft are the same, then select the preferred rotation direction as the rotation direction for multi-aircraft conflict resolution;

[0069] If the preferred rotation directions of the UAV with respect to all potential collision aircraft are not the same, then for each potential collision aircraft, calculate the distance between the UAV and the potential collision aircraft at a preset moment during the obstacle avoidance flight based on the counterclockwise direction and the clockwise direction respectively, and use it as the dangerous distance; the preset moment is the moment when the relative velocity vector of the UAV and the potential collision aircraft points to the center point of the potential collision aircraft;

[0070] Compare the dangerous distances between the UAV corresponding to the counterclockwise direction and all potential collision aircraft, and select the minimum value among them as the minimum dangerous distance in the counterclockwise direction; compare the dangerous distances between the UAV corresponding to the clockwise direction and all potential collision aircraft, and select the minimum value among them as the minimum dangerous distance in the clockwise direction;

[0071] Compare the minimum dangerous distance in the counterclockwise direction and the minimum dangerous distance in the clockwise direction, and select the rotation direction corresponding to the larger value among them as the rotation direction for multi-aircraft conflict resolution according to the safety principle.

[0072] Compared with the prior art, the present invention can at least achieve one of the following beneficial effects:

[0073] 1. The present invention provides a method for multi-aircraft dynamic conflict resolution of UAVs based on speed allocation and a method for dynamic conflict resolution of UAVs based on heading allocation, which are used to solve the problem of multi-aircraft dynamic conflicts. By planning the speed or heading of the UAV and the obstacle avoidance flight distance, the UAV can avoid multiple aircraft at the same time. The mathematical model is simple and the calculation is fast, meeting the real-time requirement of obstacle avoidance.

[0074] Specifically, when there is a potential collision risk between the UAV and multiple flights, first perform single-aircraft conflict resolution calculations for each potential collision aircraft respectively, and obtain all the speed adjustment methods or rotation directions that can achieve conflict resolution and the corresponding allocation parameters in the single-aircraft conflict calculation results. Then compare the single-aircraft conflict resolution calculation results of all potential collision aircraft, so as to select the conflict resolution plan result that can be applied to all potential aircraft and is optimal, and realize multi-aircraft dynamic conflict resolution.

[0075] 2. In the present invention, when performing single - aircraft conflict resolution calculation, the maneuverability parameters of the UAV are fully considered. Specifically, in the method based on speed allocation, maneuverability parameters such as the maximum longitudinal acceleration, the minimum longitudinal speed, and the maximum longitudinal speed are fully considered, and the speed allocation parameters for the UAV to achieve conflict resolution can be accurately calculated. In the method for multi - aircraft dynamic conflict resolution of UAVs based on speed allocation of the present invention, when performing single - aircraft conflict resolution calculation, maneuverability parameters such as the maximum angular velocity are fully considered, and the heading allocation parameters for the UAV to achieve conflict resolution can be accurately calculated, making the planned resolution scheme close to the actual flight situation, thereby improving the collision avoidance safety and stability of the UAV in actual flight.

[0076] In the present invention, the above - mentioned technical solutions can also be combined with each other to achieve more preferred combined solutions. Other features and advantages of the present invention will be described in the subsequent description. Moreover, some advantages can be made obvious from the description, or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the content specifically pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The drawings are only for the purpose of showing specific embodiments and are not considered as a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0078] Figure 1 is a flowchart of the method for multi - aircraft dynamic conflict resolution of UAVs based on speed allocation according to an embodiment of the present invention;

[0079] Figure 2 is a schematic diagram of the principle for detecting potential collision aircraft according to an embodiment of the present invention;

[0080] Figure 3 is a schematic diagram of the principle for single - aircraft conflict resolution calculation based on speed allocation according to an embodiment of the present invention;

[0081] Figure 4 is a schematic diagram of the principle for multi - aircraft dynamic conflict resolution based on speed allocation according to an embodiment of the present invention;

[0082] Figure 5 is a flowchart of the method for multi - aircraft dynamic conflict resolution of UAVs based on heading allocation according to an embodiment of the present invention;

[0083] Figure 6 is a schematic diagram of the principle for single - aircraft conflict resolution calculation based on heading allocation according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0084] The preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0085] The embodiments of the present invention provide a method for resolving multi - drone dynamic conflict based on speed allocation and a method for resolving multi - drone dynamic conflict based on heading allocation, which achieve multi - drone conflict resolution through speed allocation and heading allocation respectively. In the method based on speed allocation and the method based on heading allocation in the embodiments of the present invention, for each potentially colliding aircraft, single - aircraft conflict resolution calculation is first performed based on the corresponding maneuverability parameters of the drone, and then the single - aircraft conflict resolution calculation results of all potentially colliding aircraft are compared. According to the consistency principle, safety principle, and maximum - value principle, the optimal conflict resolution plan result that can be applied to all potential aircraft is selected to achieve multi - drone dynamic conflict resolution.

[0086] In the embodiments of the present invention, the method for resolving multi - drone dynamic conflict based on speed allocation avoids obstacles by adjusting the speed of the drone without changing the heading, so there will be no heading deviation, making it easier for the drone to restore the flight path; the method for resolving multi - drone dynamic conflict based on heading allocation avoids obstacles by adjusting the heading of the drone, and the drone can perform the heading allocation operation more conveniently. During implementation, the speed - allocation obstacle - avoidance method or the heading - allocation obstacle - avoidance method can be selected according to actual needs to achieve multi - drone dynamic conflict resolution.

[0087] It should be noted that in the embodiments of the present invention, the flight route refers to the flight path of the drone; the flight track refers to the flight trajectory of the drone, including the flight speed, heading, position, etc. of the drone at each moment.

[0088] Example 1

[0089] The embodiments of the present invention provide a method for resolving multi - drone dynamic conflict based on speed allocation, as Figure 1 shown in. The method includes:

[0090] Step A1, when the drone executes a flight mission, detect whether there are potentially colliding aircraft in the current airspace that have a potential collision risk with the drone based on the speed - obstacle method;

[0091] Step A2: If multiple potential collision aircraft are detected, for each potential collision aircraft, perform single-aircraft conflict resolution calculation based on the mobility parameters of the UAV to obtain the speed adjustment methods that the UAV can successfully resolve the conflict for each potential collision aircraft and the corresponding deployment parameters; the mobility parameters include the maximum longitudinal acceleration, the minimum longitudinal speed, and the maximum longitudinal speed; the speed adjustment methods include acceleration methods and deceleration methods; the deployment parameters include the obstacle avoidance flight distance and the speed adjustment amount.

[0092] Step A3: Compare the single-aircraft conflict resolution calculation results of all potential collision aircraft, and select a speed adjustment method as the speed adjustment method for multi-aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual deployment parameters from the deployment parameters corresponding to the speed adjustment method for multi-aircraft conflict resolution according to the maximum principle.

[0093] Step A4: The UAV adjusts its speed to the obstacle avoidance flight speed at the maximum longitudinal acceleration according to the obtained speed adjustment method for multi-aircraft conflict resolution and the actual speed adjustment amount, and then the UAV flies at a constant speed at the obstacle avoidance speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, so as to achieve multi-aircraft dynamic conflict resolution.

[0094] Compared with the prior art, the method for multi-aircraft dynamic conflict resolution of UAVs based on speed deployment implemented in the present invention is used to solve the problem of multi-aircraft dynamic conflict. By planning the speed of the UAV and the obstacle avoidance flight distance, the UAV can avoid multiple aircraft at the same time. The mathematical model is simple and the calculation is fast, meeting the real-time requirement of obstacle avoidance.

[0095] Specifically, when there is a potential collision risk between the UAV and multiple aircraft, first perform single-aircraft conflict resolution calculation for each potential collision aircraft respectively, and the obtained single-aircraft conflict calculation results include all speed adjustment methods or rotation directions that can achieve conflict resolution and the corresponding deployment parameters, and then compare all the single-aircraft conflict resolution calculation results of all potential collision aircraft, so as to select the conflict resolution plan result that is applicable to all potential collision aircraft and optimal, and achieve multi-aircraft dynamic conflict resolution.

[0096] When performing single-aircraft conflict resolution calculation in the embodiment of the present invention, both acceleration methods and deceleration methods are comprehensively considered, and then the actual conflict resolution plan result of the UAV is determined according to the consistency principle, the safety principle, and the maximum principle, which not only improves the possibility of achieving multi-aircraft dynamic conflict resolution, but also improves the obstacle avoidance safety of the UAV.

[0097] Among them, the consistency principle is used to select the speed adjustment method applicable to all potential collision aircraft, the safety principle is used to select a better speed adjustment method, and the maximum principle is used to select the deployment parameters applicable to all potential collision aircraft.

[0098] Step A1. When the UAV executes a flight mission, it detects whether there are potential collision aircraft in the current airspace that have a potential collision risk with the UAV based on the velocity obstacle method, including the following steps:

[0099] Judge the height difference H between the UAV and the target aircraft S Whether it exceeds the height difference threshold H 0 , and the three-dimensional distance d 3D Whether it exceeds the distance threshold d 0 ;

[0100] If H S ≤H 0 and d 3D ≤d 0 , then judge the distance D R between the center point of the target aircraft and the velocity vector difference V of the UAV and the target aircraft L Whether it exceeds the safety circle radius R of the target aircraft;

[0101] If D L ≤R, it is determined that the target aircraft is a potential collision aircraft.

[0102] During implementation, after obtaining the information of the UAV itself and the surrounding aircraft, based on the velocity obstacle method, it is judged one by one whether the surrounding aircraft are potential collision aircraft with potential collision risks. When the number of potential collision aircraft is greater than or equal to two, then for each potential collision aircraft, single-aircraft conflict resolution calculation is performed respectively, and then the single-aircraft conflict resolution calculation results of the potential collision aircraft are compared to obtain a conflict resolution plan result that can avoid all potential collision aircraft at the same time.

[0103] Specifically, calculate the height difference and three-dimensional distance between the UAV and the target aircraft according to their position information. If the height difference between the two exceeds the height difference threshold, or the three-dimensional distance exceeds the distance threshold, it means that there is no conflict between the UAV and the target aircraft. If not, it is necessary to further judge the distance D R between the center point of the target aircraft and the velocity vector difference V of the UAV and the target aircraft L Whether it exceeds the safety circle radius R of the target aircraft. If D L ≤R, it means that there is a potential collision risk between the UAV and the target aircraft, and it is necessary to adjust the speed and / or heading of the UAV through trajectory planning to achieve conflict resolution.

[0104] It should be noted that in the embodiments of the present invention, the unmanned aircraft is simplified to a mass point, and the target aircraft is expanded into a circle with a radius of R, that is, the safety circle. Among them, both the height difference threshold and the distance threshold are greater than the radius of the safety circle of the target aircraft. In addition, both the height difference threshold and the distance threshold are preset critical values and can be set according to actual needs.

[0105] Define the position of the UAV as A and the current speed as V A ; the position of the target aircraft is O, the safety circle radius is R, and the flight speed is V 0 . As Figure 2 shown, V R = V A - V 0 , it can be seen that D L < R, then there is a potential collision risk between the UAV and the target aircraft.

[0106] In addition, when judging that there is a potential collision risk between the UAV and the target aircraft, the information of the closest collision position and collision time between the UAV and the target aircraft can be returned.

[0107] Specifically, the distance between the UAV and the closest collision position is D AB , and its calculation formula is:

[0108]

[0109] The collision time T AB between the UAV and the target aircraft is calculated as:

[0110] T AB = D AB / ||V A ||.

[0111] The reception and forwarding of the real-time information of the UAV and the aircraft are mainly processed by the ground station software, including the information of the UAV itself, the information of the surrounding aircraft, etc. The information of the UAV itself includes the position, speed information and maneuverability parameters of the UAV. Among them, the position information includes longitude, latitude, altitude, etc., the speed information includes ground speed, ground track angle, longitudinal speed and vertical speed, etc., and the maneuverability parameters include longitudinal acceleration, maximum angular velocity, minimum longitudinal speed and maximum longitudinal speed, etc. The information of the surrounding aircraft can generally be obtained through the ADS-B system (Automatic Dependent Surveillance - Broadcast), including the position and speed information of the aircraft. The position information includes longitude, latitude, altitude, heading angle, etc., and the speed information includes longitudinal speed, vertical speed, etc.

[0112] In step A2, the method for calculating the single - aircraft conflict resolution based on the maneuverability parameters of the UAV is as follows:

[0113] Define the initial position of the drone as A and the initial velocity as V A_0 ; The initial position of the target aircraft is O, the safety circle radius is R, and the flight speed is V 0 ; The initial distance between the drone and the target aircraft is L AO ;

[0114] Determine the release point position B corresponding to the acceleration mode and the release point position C corresponding to the deceleration mode according to the relative velocity vector of the drone and the target aircraft and the safety circle of the target aircraft;

[0115] Calculate the obstacle avoidance flight distance L of the drone corresponding to the acceleration mode and the deceleration mode according to the following formula AD and the obstacle avoidance flight time T required to reach the obstacle avoidance flight distance L AD : total :

[0116] ||V A_1 || = ||-V 0 || · (sinα / sinβ);

[0117] ||V R_1 || = ||-V 0 || · (sin(α + β) / sinβ);

[0118]

[0119] T total = L AD / ||V A_1 ||;

[0120] In the formula, is the relative velocity vector for the drone to avoid the target aircraft. In the acceleration mode In the deceleration mode, α is the angle between -V 0 and ; V A_1 is the velocity that can achieve conflict resolution assuming the drone can instantaneously change its velocity. V A_1 has the same direction as V A_0 ; β is the angle between V A_1 and ; V R_1 is V A_1 and V 0 's relative velocity vector, V R_1 = V A_1 -V 0 ;

[0121] According to the obstacle avoidance flight distance L of the drone AD and the obstacle avoidance flight time T totalJudge whether the UAV can escape successfully through acceleration or deceleration respectively according to the maneuverability parameters of the UAV. The formula is:

[0122]

[0123]

[0124]

[0125] In the formula, V A_max and V A_min are the maximum longitudinal speed and the minimum longitudinal speed of the UAV respectively, V A_max > V A_min > 0; V A_limit is the speed limit of the UAV; L max is the maximum distance that the UAV can actually fly; T min is the minimum time required for the UAV to reach the speed limit; a is the acceleration of the UAV. In the acceleration mode, a = a max , and in the deceleration mode, a = -a max ;

[0126] If L max < L AD , then it cannot escape successfully; if L max ≥ L AD , then it can escape successfully;

[0127] If it can escape successfully, then calculate the speed adjustment amount ΔV AD of the UAV, the time T total required for the UAV to accelerate to the obstacle avoidance speed V A_1 +ΔV A_0 A_1 and the time T 1 for the UAV to fly at a constant speed at the obstacle avoidance flight speed V A_0 +ΔV A_1 2 according to the obstacle avoidance flight distance L AD . The formula is:

[0128] L AD = V A_0 ·T 1 +(a·T 1 2 ) / 2+(V A_0 +a·T 1 )·(T total -T 1 );

[0129] ΔV A_1 = a·T 1 ;

[0130] T 2 = T total - T 1 。

[0131] In the single - aircraft conflict resolution calculation of the embodiments of the present invention, it is considered to adjust the speed of the UAV by accelerating or decelerating methods to achieve conflict resolution. And according to the maximum longitudinal acceleration of the UAV, the obstacle - avoidance speed of the UAV, as well as the acceleration / deceleration and variable - speed (acceleration or deceleration) flight time and constant - speed flight time are calculated.

[0132] Figure 3 The principle of single - aircraft conflict resolution calculation based on speed allocation in the embodiments of the present invention is shown. If the UAV can instantaneously adjust its speed to V A_1 , it can successfully avoid the safety circle of the target aircraft. Further, according to V A_1 , the obstacle - avoidance flight distance L AD and the obstacle - avoidance flight time T total can be calculated, that is, the UAV needs to fly a distance L total in time T AD to avoid the safety circle of the aircraft. At the same time, due to the mobility constraints of the UAV, it is impossible for the UAV to instantaneously adjust from the initial speed V A_0 to V A_1 . Considering the mobility parameters of the UAV, corresponding conversion calculations are carried out. The specific conversion principle is that the UAV first accelerates or decelerates to a certain speed with full power, and then maintains a constant - speed flight, just flying a distance L total in time T AD , so that it can be the same as the UAV instantaneously accelerating to V A_1 , and then maintaining a constant - speed flight for time T total and flying a distance L AD , achieving the same effect.

[0133] At the same time, before the conversion calculation, according to the mobility parameters such as the maximum longitudinal acceleration, the maximum longitudinal speed and the minimum longitudinal speed of the UAV, it is judged whether the UAV can fly a distance L total in time T AD . Specifically, according to the above - mentioned mobility parameters, the maximum distance L max that the UAV can actually fly by using the acceleration method and the deceleration method is calculated. If L max < L AD , it means that the UAV cannot reach the release point position by adjusting the speed in time T total , that is, the conflict cannot be resolved successfully; if L max ≥L AD , it means that the UAV can reach the release point position by adjusting the speed in time T total , that is, the conflict can be resolved successfully.

[0134] If the disengagement is successful, the speed adjustment amount ΔV of the UAV can be further calculated. A_1 and the time T for variable speed (acceleration or deceleration) flight 1 and the time T for uniform speed flight 2 and other parameters.

[0135] Step A3: Compare the single - aircraft conflict disengagement calculation results of all potential collision aircraft, select a speed adjustment method as the speed adjustment method for multi - aircraft conflict disengagement according to the consistency principle and the safety principle, and then obtain the actual deployment parameters from the deployment parameters corresponding to the speed adjustment method for multi - aircraft conflict disengagement according to the principle of taking the larger value.

[0136] In the embodiment of the present invention, the consistency principle is used to select a speed adjustment method applicable to all potential conflict aircraft, the safety principle is used to select a better speed adjustment method, and the principle of taking the larger value is used to select the deployment parameters applicable to all potential conflict aircraft.

[0137] In step A3, the selection of a speed adjustment method as the speed adjustment method for multi - aircraft conflict disengagement according to the consistency principle and the safety principle includes:

[0138] Step A301: After comparing the single - aircraft conflict disengagement calculation results of all potential collision aircraft, if only one speed adjustment method can successfully disengage the UAV from all potential collision aircraft, select this speed adjustment method as the speed adjustment method for multi - aircraft conflict disengagement;

[0139] Step A302: After comparing the single - aircraft conflict disengagement calculation results of all potential collision aircraft, if two speed adjustment methods can both successfully disengage the UAV from all potential collision aircraft, judge the safer speed adjustment method of the UAV for the potential collision aircraft according to the relative position of the relative velocity vector of the UAV and the potential aircraft and the safety circle of the potential collision aircraft, and use it as the preferred speed adjustment method;

[0140] Step A303: Compare the preferred speed adjustment methods of the UAV for each potential collision aircraft, and select a speed adjustment method from the preferred speed adjustment methods as the speed adjustment method for multi - aircraft conflict disengagement according to the consistency principle and the safety principle..

[0141] In the embodiments of the present invention, if both speed regulation methods can successfully disengage the UAV from all potential collision aircraft, a better speed regulation method for each potential collision aircraft is selected based on obstacle avoidance safety. Then, according to the consistency principle and the safety principle, a speed regulation method is selected from the preferred speed regulation methods as the speed regulation method for multi-aircraft conflict resolution. In step A302, the obstacle avoidance safety is judged according to the relative position between the relative speed vector of the UAV and the potential aircraft and the safety circle of the potential collision aircraft. Specifically, the relative position between the relative speed vector of the UAV and the potential collision aircraft and the safety circle of the potential collision aircraft can reflect the change of the closest distance between the UAV and the target aircraft. Among them, the mode in which the closest distance between the UAV and the target aircraft is always increasing is more conducive to obstacle avoidance safety.

[0142] The following is an example to illustrate how to select the preferred speed regulation method.

[0143] As Figure 3 shown, the critical relative speed vector directions of the UAV to avoid the safety circle of the aircraft are the AB direction and the AC direction. That is, as long as the relative speed vector of the UAV and the target aircraft is along the AB or AC direction, the UAV will successfully avoid the safety circle of the aircraft. In order to change the relative speed direction between the UAV and the target aircraft to the AB or AC direction, it can be achieved by accelerating or decelerating the UAV. Figure 3 In, the relative speed direction between the UAV and the target aircraft points between point O and point B. The relative speed between the UAV and the target aircraft can become the AB direction by accelerating and the AC direction by decelerating. At the same time, according to the relative position between the relative speed vector of the UAV and the target aircraft and the safety circle of the target aircraft, it can be seen that when the acceleration method is adopted, the closest distance between the UAV and the target aircraft is always increasing; when the deceleration method is adopted, the closest distance between the UAV and the target aircraft first decreases and then increases. Therefore, considering obstacle avoidance safety, the acceleration method is the preferred speed regulation method.

[0144] After determining the preferred speed regulation method for each potential collision aircraft, there will also be two situations. One is that the preferred speed regulation methods of the UAV for each potential collision aircraft are the same, and the preferred speed regulation method is directly used as the speed regulation method for multi-aircraft conflict resolution of the UAV. The other is that the preferred speed regulation methods of the UAV for each potential collision aircraft are different. For this situation, in the embodiments of the present invention, the obstacle avoidance safety of the two speed regulation methods is judged respectively by other safety indicators. In a specific embodiment, the safety indicator - the "longest obstacle avoidance flight time" corresponding to each speed regulation method is used for judgment; in another specific embodiment, the safety indicator - the "minimum dangerous distance" corresponding to each speed regulation method is used for judgment.

[0145] In a specific embodiment, step A303 includes the following sub-steps: step A303-a1, if the preferred speed adjustment methods for the UAV with respect to each potential collision aircraft are the same, then select the preferred speed adjustment method as the speed adjustment method for multi-aircraft conflict resolution;

[0146] Step A303-a2, if the preferred speed adjustment methods for the UAV with respect to each potential collision aircraft are not the same, then compare the longest obstacle avoidance flight times corresponding to the two speed adjustment methods, and select the speed adjustment method corresponding to the smaller value based on the safety principle as the speed adjustment method for multi-aircraft conflict resolution.

[0147] In the embodiment of the present invention, the "longest obstacle avoidance flight time" corresponding to each speed adjustment method is further used to judge the obstacle avoidance safety. Specifically, the shorter the "longest obstacle avoidance flight time" is, the faster the UAV can achieve multi-aircraft dynamic conflict resolution, and thus the higher the obstacle avoidance safety is.

[0148] It should be noted that when performing single-aircraft conflict calculation for each potential collision aircraft, the obstacle avoidance flight time corresponding to the acceleration method and the obstacle avoidance flight time of the deceleration method of the UAV relative to each potential collision aircraft can be obtained respectively. Among them, the maximum value of the obstacle avoidance flight times corresponding to each speed adjustment method is the longest obstacle avoidance flight time.

[0149] In another specific embodiment, step A303 includes the following sub-steps, including:

[0150] Step A303-b1, if the preferred speed adjustment methods for the UAV with respect to each potential collision aircraft are the same, then select the preferred speed adjustment method as the speed adjustment method for multi-aircraft conflict resolution;

[0151] Step A303-b2, if the preferred speed adjustment methods for the UAV with respect to each potential collision aircraft are not the same, then for each potential collision aircraft, calculate the distance between the UAV and the potential collision aircraft at a preset moment during the obstacle avoidance flight process when the UAV adjusts its speed based on the acceleration method and the corresponding deployment parameters and the deceleration method and the corresponding deployment parameters, and use it as the dangerous distance; the preset moment is the moment when the relative velocity vector of the UAV and the potential collision aircraft points to the center point of the potential collision aircraft;

[0152] Step A303-b3, compare the dangerous distances between the UAV corresponding to the acceleration method and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance of the acceleration method; compare the dangerous distances between the UAV corresponding to the deceleration method and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance of the deceleration method;

[0153] Step A303-b4: Compare the minimum dangerous distance of the acceleration mode and the minimum dangerous distance of the deceleration mode, and select the speed regulation mode corresponding to the larger value based on the safety principle as the speed regulation mode for multi-aircraft conflict resolution.

[0154] In this embodiment, for each potentially colliding aircraft, at the above preset moment, the relative velocity vector of the UAV and the potentially colliding aircraft points to the center point of the potentially colliding aircraft. At this time, the UAV and the potentially colliding aircraft are in the most dangerous state. If the UAV malfunctions at this time, it is very likely to collide with the potentially colliding aircraft. Therefore, the above preset moment is considered the most dangerous moment between the two, and the distance between the UAV and the potentially colliding aircraft at the preset moment can be used to judge the safety of obstacle avoidance.

[0155] During implementation, in step A303-b2, the dangerous distance can be calculated using Vincenty's formula or the geometric method. Among them, Vincenty's formula is also known as the geodetic problem formula. The geodetic problem includes the direct geodetic problem and the inverse geodetic problem. The direct geodetic problem is to know the geodetic longitude B 1 、L 1 of point 1 and the geodetic azimuth A 1-2 from point 1 to point 2 and the geodetic line length s, and deduce the geodetic longitude B 2 、L 2 of point 2 and the geodetic azimuth A 2-1 from point 2 to point 1.

[0156] In step A3, then obtain the actual deployment parameters from the deployment parameters corresponding to the speed regulation mode for multi-aircraft conflict resolution according to the principle of taking the larger value.

[0157] As Figure 4 shown, there is a potential collision risk between the UAV and two aircraft. The two potentially colliding aircraft are O 1 and O 2 . Assume that multi-aircraft conflict resolution can be achieved based on speed deployment, and the speed regulation mode for UAV multi-aircraft conflict resolution is the acceleration mode; for the potentially colliding aircraft O 1 , the speed adjustment amount is ΔV A_1_1 , and the obstacle avoidance flight distance is For the potentially colliding aircraft O 2 , the speed adjustment amount is ΔV A_1_2 , and the obstacle avoidance flight distance is If ΔV A_1_1 > ΔV A_1_2 , then the actual speed adjustment amount of the UAV is ΔV A_1_1 , and the actual obstacle avoidance flight distance is

[0158] Step A4: The UAV adjusts its speed to the obstacle avoidance flight speed at the maximum longitudinal acceleration according to the obtained speed regulation method for multi-UAV conflict resolution and the actual speed adjustment amount, and then the UAV flies at a constant speed at the obstacle avoidance speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, thus realizing multi-UAV dynamic conflict resolution.

[0159] In this embodiment, considering the mobility parameter of the UAV - the maximum longitudinal acceleration, when avoiding obstacles, the UAV first accelerates to the obstacle avoidance flight speed with full power and then flies at a constant speed at the obstacle avoidance flight speed, which is conducive to realizing multi-UAV conflict resolution as soon as possible.

[0160] In addition, the UAV flies the planned flight distance within the planned time according to the obtained speed regulation method for multi-UAV conflict resolution and the actual deployment parameters, so as to reach the planned conflict resolution point position and realize conflict resolution. At this time, the conflict resolution calculation ends until a new conflict situation is encountered and the conflict resolution calculation is started again.

[0161] Example 2

[0162] An embodiment of the present invention provides a method for multi-UAV dynamic conflict resolution based on heading deployment, as Figure 5 shown in. The method includes:

[0163] Step B1: When the UAV executes a flight mission, based on the velocity obstacle method, it detects whether there are potential collision aircraft in the current airspace that have a potential collision risk with the UAV;

[0164] Step B2: If multiple potential collision aircraft are detected, for each potential collision aircraft, a single-UAV conflict resolution calculation is respectively performed based on the mobility parameters of the UAV to obtain the rotation direction in which the UAV can successfully resolve the conflict for each potential collision aircraft and the corresponding deployment parameters; the mobility parameters include the maximum angular velocity; the rotation direction includes the counterclockwise direction and the clockwise direction; the deployment parameters include the obstacle avoidance flight distance and the rotation angle;

[0165] Step B3: Compare the single-UAV conflict resolution calculation results of all potential collision aircraft, and select a rotation direction as the rotation direction for multi-UAV conflict resolution according to the consistency principle and the safety principle, and then obtain the actual deployment parameters from the deployment parameters corresponding to the rotation direction for multi-UAV conflict resolution according to the maximum principle;

[0166] Step B4: The UAV adjusts its heading at the maximum angular velocity according to the obtained rotation direction for multi-UAV conflict resolution and the actual rotation angle, and maintains a constant speed flight at the initial speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, thus realizing multi-UAV dynamic conflict resolution.

[0167] Compared with the prior art, the method for multi - drone dynamic conflict resolution based on heading allocation in the embodiments of the present invention is used to solve the problem of multi - drone dynamic conflicts. By planning the headings and obstacle - avoidance flight distances of the drones, the drones can avoid multiple flying vehicles simultaneously. The mathematical model is simple and the calculation is fast, meeting the real - time requirement of obstacle avoidance.

[0168] Specifically, when there is a potential collision risk between a drone and multiple flying objects, first, for each potentially colliding flying vehicle, single - drone conflict resolution calculation is performed separately, and the obtained single - drone conflict resolution calculation results include all the rotation directions that can achieve conflict resolution and the corresponding allocation parameters. Then, compare the single - drone conflict resolution calculation results of all potentially colliding flying vehicles to select the optimal resolution plan result that is applicable to all potentially colliding flying vehicles, thus achieving multi - drone dynamic conflict resolution.

[0169] When performing single - drone conflict resolution calculation in the embodiments of the present invention, both counter - clockwise and clockwise rotation directions are comprehensively considered. Then, according to the consistency principle, safety principle, and maximum - value principle, the actual resolution plan result of the drone is determined, which not only improves the possibility of achieving multi - drone dynamic conflict resolution but also enhances the obstacle - avoidance safety of the drones.

[0170] Among them, the consistency principle is used to select the rotation direction applicable to all potentially conflicting flying vehicles, the safety principle is used to select a better rotation direction, and the maximum - value principle is used to select the allocation parameters applicable to all potentially conflicting flying vehicles.

[0171] In step B1 of this embodiment, when the drone executes a flight mission, the method for detecting whether there are potentially colliding flying vehicles with potential collision risks with the drone in the current airspace based on the velocity obstacle method is the same as that in step A1 of Embodiment 1, and will not be elaborated here.

[0172] Step B2, the method for performing single - drone conflict resolution calculation based on the mobility parameters of the drone is as follows:

[0173] Define the initial position of the drone as A and the initial velocity as V A_0 ; the initial position of the target flying vehicle is O, the safety circle radius is R, and the flight speed is V 0 ; the initial distance between the drone and the target flying vehicle is L AO ;

[0174] According to the relative velocity vector between the drone and the target flying vehicle and the safety circle of the target flying vehicle, determine the position B' of the resolution point corresponding to the counter - clockwise direction and the position C' of the resolution point corresponding to the clockwise direction;

[0175] Calculate the rotation angle θ and the obstacle - avoidance flight distance L of the drone corresponding to the counter - clockwise direction and the clockwise direction according to the following formulaAD and the obstacle avoidance flight distance L is reached AD The required obstacle avoidance flight time T' total , the formula is:

[0176] ||V A_2 || / sinα|| - V 0 || / sinδ;

[0177] ||V A_2 || = ||V A_0 ||;

[0178] V R_2 = V A_2 - V 0 ;

[0179] δ = arcsin(|| - V 0 ||·sinα / ||V A_2 ||);

[0180] θ = δ - β;

[0181]

[0182] L AD = ||V A_0 ||·T' total ;

[0183] In the formula, V A_2 is the velocity vector after the UAV rotates by the angle θ; V R_2 is the relative velocity vector between the UAV and the target aircraft after the UAV rotates by the angle θ; The relative velocity vector of the UAV to avoid potential aircraft, when rotating counterclockwise when rotating clockwise, α is the angle between -V 0 and ; β is the angle between the velocity vector V A_0 and the vector ; δ is the angle between the velocity vector V A_2 and V R_2 ; when the UAV rotates counterclockwise, 0 < θ < 90°; when the UAV rotates clockwise, -90° < θ < 0;

[0184] After obtaining the rotation angle θ of the UAV and the obstacle avoidance flight time T' of the UAV total , it is judged whether the UAV can successfully escape by rotating counterclockwise or clockwise according to the maximum angular velocity ω of the UAV,

[0185] If θ ≤ ω·T' total , then the UAV can successfully escape. If θ > ω·T'total , the UAV cannot successfully disengage.

[0186] In the UAV multi-aircraft dynamic conflict resolution method based on heading allocation according to the embodiments of the present invention, the UAV rotates to adjust its heading to achieve conflict resolution. When calculating the single-aircraft conflict resolution, the maximum angular velocity of the UAV is considered to calculate the rotation angle of the UAV.

[0187] Figure 6 Fig. shows the single-aircraft conflict resolution calculation principle (counterclockwise direction) based on heading allocation according to the embodiments of the present invention. When the flight speed remains unchanged, if the UAV can instantaneously rotate an angle θ, it can successfully avoid the safety circle of the target aircraft. The maneuverability constraint of the UAV determines that the UAV cannot instantaneously rotate an angle θ. It is necessary to judge whether the UAV can rotate an angle θ within time T' according to the maneuverability parameter of the UAV - the maximum angular velocity. total If so, the UAV can successfully disengage; if not, the UAV cannot successfully disengage. And when calculating the rotation angle θ, the relative velocity between the UAV and the target aircraft after the UAV rotates an angle θ can be obtained, and then the obstacle avoidance flight distance L AD and the obstacle avoidance flight time T' total .

[0188] Step B3: Compare the single-aircraft conflict resolution calculation results of all potential collision aircraft, and select a rotation direction as the rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual allocation parameters from the allocation parameters corresponding to the rotation direction of the multi-aircraft conflict resolution according to the principle of taking the larger value.

[0189] In the embodiments of the present invention, the consistency principle is used to select the rotation direction applicable to all potential collision aircraft, the safety principle is used to select a better rotation direction, and the principle of taking the larger value is used to select the allocation parameters applicable to all potential collision aircraft.

[0190] In step B3, the selection of a rotation direction as the rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle includes:

[0191] Step B301: After comparing the single-aircraft conflict resolution calculation results of all potential collision aircraft, if only one rotation direction can enable the UAV to successfully disengage from all potential collision aircraft, then select this rotation direction as the rotation direction for multi-aircraft conflict resolution;

[0192] Step B302: After comparing the single-vehicle conflict resolution calculation results obtained by all potential collision aircraft, if both rotation directions can successfully resolve the conflict between the UAV and all potential collision aircraft, determine the safer rotation direction of the UAV for the potential collision aircraft based on the relative position of the relative velocity vector between the UAV and the potential aircraft and the safety circle of the potential collision aircraft, and use it as the preferred rotation direction;

[0193] Step B303: Compare the preferred rotation directions of the UAV for each potential collision aircraft, and select a rotation direction from the preferred rotation directions as the rotation direction for multi-vehicle conflict resolution according to the consistency principle and the safety principle. In the embodiment of the present invention, if both rotation directions can successfully resolve the conflict between the UAV and all potential collision aircraft, based on the obstacle avoidance safety, select a better rotation direction for each potential collision aircraft, and then determine a rotation direction from the preferred rotation directions as the rotation direction for multi-vehicle conflict resolution according to the consistency principle and the safety principle. In step B302, the obstacle avoidance safety is judged according to the relative position of the relative velocity vector between the UAV and the potential aircraft and the safety circle of the potential collision aircraft. Specifically, the relative position of the relative velocity vector between the UAV and the potential collision aircraft and the safety circle of the potential collision aircraft can reflect the change of the closest distance between the UAV and the target aircraft. Among them, the mode in which the closest distance between the UAV and the target aircraft is always increasing is more conducive to obstacle avoidance safety.

[0194] The following is an example to illustrate how to select the preferred rotation direction.

[0195] As Figure 6 shown, the critical relative velocity vector directions for the UAV to avoid the safety circle of the aircraft are the AB direction and the AC direction, that is, as long as the relative velocity vector between the UAV and the target aircraft is along the AB or AC direction, the UAV will successfully avoid the safety circle of the aircraft. To change the relative velocity direction of the UAV to the AB or AC direction, the heading of the UAV can be changed. Figure 6 In, the relative velocity direction between the UAV and the target aircraft points between point O and point B. The relative velocity between the UAV and the target aircraft can be changed to the AB direction by counterclockwise rotation and to the AC direction by clockwise rotation. At the same time, according to the relative position of the relative velocity vector between the UAV and the target aircraft and the safety circle of the target aircraft, it can be seen that when the counterclockwise direction is adopted, the closest distance between the UAV and the target aircraft is always increasing; when the clockwise direction is adopted, the closest distance between the UAV and the target aircraft first decreases and then increases. Therefore, considering the obstacle avoidance safety, the counterclockwise direction is the preferred rotation direction.

[0196] After determining the preferred rotation direction of each potential collision aircraft, two situations will also occur. One is that the preferred rotation directions of the UAV for each potential collision aircraft are the same, and then the preferred rotation direction is directly used as the rotation direction for multi-aircraft conflict resolution of the UAV. The other is that the preferred rotation directions of the UAV for each potential collision aircraft are not the same. For this situation, in the embodiments of the present invention, the obstacle avoidance safety of the two speed regulation methods is respectively judged by additional safety indicators. In a specific embodiment, the safety indicator - the "longest obstacle avoidance flight time" corresponding to each rotation direction is used for judgment; in another specific embodiment, the safety indicator - the "minimum danger distance" corresponding to each rotation direction is used for judgment.

[0197] In a specific embodiment, step B303 includes the following sub-steps

[0198] Step B303-a1, if the preferred rotation directions of the UAV for each potential collision aircraft are the same, then select the preferred rotation direction as the rotation direction for multi-aircraft conflict resolution;

[0199] Step B303-a2, if the preferred rotation directions of the UAV for each potential collision aircraft are not the same, then compare the longest obstacle avoidance flight times corresponding to the two rotation directions, and select the rotation direction corresponding to the smaller value according to the safety principle as the rotation direction for multi-aircraft conflict resolution.

[0200] In the embodiments of the present invention, the obstacle avoidance safety is further judged by the "longest obstacle avoidance flight time" corresponding to each speed regulation method. Specifically, the shorter the "longest obstacle avoidance flight time" is, the faster the UAV can achieve multi-aircraft dynamic conflict resolution, and thus the higher the obstacle avoidance safety is.

[0201] It should be noted that when performing single-aircraft conflict calculation for each potential collision aircraft, the obstacle avoidance flight time corresponding to the counterclockwise direction and the clockwise direction of the UAV relative to each potential collision aircraft can be respectively obtained. Among them, the maximum value of the obstacle avoidance flight times corresponding to each rotation direction is the longest obstacle avoidance flight time.

[0202] In another specific embodiment, step B303 includes the following sub-steps:

[0203] Step B303-b1, if the preferred rotation directions of the UAV for each potential collision aircraft are the same, then select the preferred rotation direction as the rotation direction for multi-aircraft conflict resolution;

[0204] Step B303-b2: If the preferred rotation directions of the UAV for each potential collision aircraft are inconsistent, then for each potential collision aircraft, calculate the distances between the UAV and the potential collision aircraft at a preset moment during the obstacle avoidance flight process when the UAV adjusts its heading based on the counterclockwise direction and the corresponding deployment parameters and the clockwise direction and the corresponding deployment parameters respectively, and take them as the dangerous distances; the preset moment is the moment when the relative velocity vector of the UAV and the potential collision aircraft points to the center point of the potential collision aircraft.

[0205] Step B303-b3: Compare the dangerous distances between the UAV corresponding to the counterclockwise direction and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance in the counterclockwise direction; compare the dangerous distances between the UAV corresponding to the clockwise direction and each potential collision aircraft, and select the minimum value among them as the minimum dangerous distance in the clockwise direction.

[0206] Step B303-b4: Compare the minimum dangerous distance in the counterclockwise direction and the minimum dangerous distance in the clockwise direction, and select the rotation direction corresponding to the larger value among them as the rotation direction for multi-aircraft conflict resolution according to the safety principle.

[0207] In this embodiment, for each potential collision aircraft, at the above-mentioned preset moment, the relative velocity vector of the UAV and the potential collision aircraft points to the center point of the potential collision aircraft. At this time, the UAV and the potential collision aircraft are in the most dangerous state. If the UAV malfunctions at this time, it is very likely to collide with the potential collision aircraft. Therefore, the above-mentioned preset moment is considered the most dangerous moment between the two, and the distance between the UAV and the potential collision aircraft at the preset moment can be used to judge the safety of obstacle avoidance.

[0208] During implementation, in Step B303-b2, the dangerous distance can be calculated using the Vincenty formula or the geometric method.

[0209] Step B4: The UAV adjusts its heading at the maximum angular velocity according to the obtained rotation direction for multi-aircraft conflict resolution and the actual rotation angle, and maintains a constant speed of the initial speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, so as to achieve multi-aircraft dynamic conflict resolution. In this embodiment, considering the maneuverability parameter of the UAV - the maximum angular velocity, during obstacle avoidance flight, the UAV keeps the speed magnitude unchanged and adjusts its heading from the initial position at the maximum angular velocity, which is conducive to achieving multi-aircraft conflict resolution as soon as possible.

[0210] It should be noted that the UAV realizes multi-aircraft conflict resolution by adopting heading deployment. While avoiding obstacles, it also deviates from the original route. Next, there are two options. One is that the UAV quickly returns to the original route and executes the flight mission according to the original heading. The other is that the UAV re-plans the route with the conflict resolution point position as the starting point.

[0211] In addition, according to the speed regulation method for multi-aircraft conflict resolution obtained and the actual deployment parameters, the UAV flies the planned flight distance within the planned time, so as to reach the planned conflict resolution point position and achieve conflict resolution. At this time, the conflict resolution calculation ends, and until a new conflict situation is encountered, the conflict resolution calculation is started again.

[0212] Those skilled in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a magnetic disk, an optical disk, a read-only memory or a random access memory, etc.

[0213] The above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for resolving dynamic conflicts among multiple unmanned aerial vehicles based on speed allocation, characterized in that: The method comprises: When the UAV is performing a flight mission, it detects whether there are potential collision aircraft in the current airspace that may pose a potential collision risk to the UAV based on the speed obstacle method; If multiple potential collision aircraft are detected, a single-aircraft conflict resolution calculation is performed for each potential collision aircraft based on the maneuverability parameters of the UAV to obtain a speed control mode and corresponding adjustment parameters for the UAV to successfully resolve each potential collision aircraft; the maneuverability parameters include the maximum longitudinal acceleration, the minimum longitudinal speed and the maximum longitudinal speed; the speed control mode includes the acceleration mode and the deceleration mode; the adjustment parameters include the obstacle avoidance flight distance and the speed adjustment amount; Compare the calculation results of single-aircraft conflict resolution of all potential collision aircraft, select a speed regulation method as the speed regulation method for multi-aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual deployment parameters from the deployment parameters corresponding to the speed regulation method for multi-aircraft conflict resolution according to the principle of taking the largest one; The UAV adjusts its speed to the obstacle avoidance flight speed with the maximum longitudinal acceleration according to the acquired speed regulation mode of multi-aircraft conflict resolution and the actual speed adjustment amount, and then the UAV flies at a constant speed at the obstacle avoidance speed until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, thereby realizing dynamic conflict resolution of multiple aircraft; The method for calculating the single-machine conflict resolution based on the maneuverability parameters of the UAV is as follows: Define the initial position of the drone as A and the initial speed as V A_0 ; The initial position of the target aircraft is O, the radius of the safety circle is R, and the flight speed is V0; the initial distance between the UAV and the target aircraft is L AO ; According to the relative velocity vector between the UAV and the target aircraft and the safety circle of the target aircraft, the release point position B corresponding to the acceleration mode and the release point position C corresponding to the deceleration mode are determined; The obstacle avoidance flight distance L of the drone corresponding to the acceleration mode and deceleration mode is calculated according to the following formula AD And reach obstacle avoidance flight distance L AD The required obstacle avoidance flight time T total : ||V A_1 ||=||-V0||·(sinα / sinβ); ||V R_1 ||=||-V0||·(sin(α+β) / sinβ); T total =L AD / ||V A_1 ||; In the formula, The relative speed vector of the drone to avoid the target aircraft, in acceleration mode In deceleration mode, α is -V0 and The angle between A_1 V is the speed at which the conflict can be resolved assuming that the UAV can change speed instantly. A_1 With V A_0 The direction is the same; β is V A_1 and The angle between R_1 V A_1 Relative velocity vector with respect to V0, V R_1 =V A_1 -V0; According to the obstacle avoidance flight distance L of the UAV AD , the obstacle avoidance flight time T total The maneuverability parameters of the UAV are used to determine whether the UAV can be successfully released by accelerating or decelerating. The formula is: Where V A_max and V A_min are the maximum longitudinal velocity and minimum longitudinal velocity of the UAV, V A_max >V A_min >0;V A_limit is the speed limit of the drone; L max The maximum distance that the drone can actually fly; T min is the minimum time required for the drone to reach the speed limit; a is the acceleration of the drone, and in the acceleration mode a=a max , in the deceleration mode, a=-a max ; If L max <L AD , then it cannot be successfully liberated; if L max ≥L AD , then you can be liberated successfully; If the escape is successful, then according to the obstacle avoidance flight distance L AD , the obstacle avoidance flight time T total Calculate the speed adjustment ΔV of the drone A_1 , the drone accelerates to the obstacle avoidance speed V A_0 +ΔV A_1 The time required T1 and the drone's obstacle avoidance flight speed V A_0 +ΔV A_1 The time T2 of uniform flight is: 50 AD =V A_0 ·T1+(a·T1 2 ) / 2+(V A_0 +a·T1)·(T total -T1); ΔV A_1 =a·T1; T2=T total -T1。 2. The method according to claim 1, characterized in that The method of selecting a speed regulation mode as the speed regulation mode for multi-machine conflict resolution according to the consistency principle and the safety principle includes: After comparing the calculation results of single-aircraft conflict resolution of all potential collision aircraft, if there is only one speed control method that can successfully resolve the UAV from all potential collision aircraft, then this speed control method is selected as the speed control method for multi-aircraft conflict resolution; After comparing the calculation results of the single-machine conflict release of all potential collision aircraft, if both speed control methods can successfully release the UAV from all potential collision aircraft, the safer speed control method of the UAV for the potential collision aircraft is determined based on the relative speed vector between the UAV and the potential collision aircraft and the relative position of the safety circle of the potential collision aircraft, and it is used as the preferred speed control method; The preferred speed control modes of the UAVs for each potential collision aircraft are compared, and a speed control mode is selected from the preferred speed control modes according to the consistency principle and the safety principle as the speed control mode for multi-aircraft conflict resolution.

3. The method according to claim 2, characterized in that The comparing the preferred speed control modes of the UAVs for the potential collision aircraft, and selecting a speed control mode from the preferred speed control modes as the speed control mode for multi-aircraft conflict resolution according to the consistency principle and the safety principle, includes: If the preferred speed control modes of the UAVs for each potential collision aircraft are consistent, the preferred speed control mode is selected as the speed control mode for multi-aircraft conflict resolution; If the preferred speed control modes for each potential collision aircraft are inconsistent, the longest obstacle avoidance flight times corresponding to the two speed control modes are compared, and the speed control mode corresponding to the smaller value is selected as the speed control mode for multi-aircraft conflict resolution based on the principle of safety.

4. The method according to claim 2, characterized in that: The comparing the preferred speed control modes of the UAVs for each potential collision aircraft, and selecting a speed control mode from the preferred speed control modes as the speed control mode for multi-aircraft conflict resolution according to the consistency principle and the safety principle, includes: if the preferred speed control modes of the UAVs for each potential collision aircraft are consistent, selecting the preferred speed control mode as the speed control mode for multi-aircraft conflict resolution; If the preferred speed control mode of the UAV for each potential collision aircraft is inconsistent, then for each potential collision aircraft, the distance between the UAV and the potential collision aircraft at a preset time during the obstacle avoidance flight based on the acceleration mode and the deceleration mode is calculated respectively, and the distance is used as the danger distance; the preset time is the time when the relative speed vector between the UAV and the potential collision aircraft points to the center point of the potential collision aircraft; Compare the danger distances between the UAV corresponding to the acceleration mode and each potential collision aircraft, and select the minimum value as the minimum danger distance of the acceleration mode; compare the danger distances between the UAV corresponding to the deceleration mode and each potential collision aircraft, and select the minimum value as the minimum danger distance of the deceleration mode; The minimum danger distance of the acceleration mode and the minimum danger distance of the deceleration mode are compared, and the speed regulation mode corresponding to the larger value is selected as the speed regulation mode for multi-machine conflict resolution according to the safety principle.

5. A method for resolving dynamic conflicts among multiple unmanned aerial vehicles based on heading adjustment, characterized in that: The method comprises: When the UAV is performing a flight mission, it detects whether there are potential collision aircraft in the current airspace that may pose a potential collision risk to the UAV based on the speed obstacle method; If multiple potential collision aircraft are detected, a single-aircraft conflict resolution calculation is performed for each potential collision aircraft based on the maneuverability parameters of the UAV to obtain the rotation direction and corresponding adjustment parameters of the UAV that can successfully resolve each potential collision aircraft; the maneuverability parameters include the maximum angular velocity; the rotation direction includes the counterclockwise direction and the clockwise direction; the adjustment parameters include the obstacle avoidance flight distance and the rotation angle; Compare the calculation results of single-aircraft conflict resolution of all potential collision aircraft, select a rotation direction as the rotation direction of multi-aircraft conflict resolution according to the consistency principle and the safety principle, and then obtain the actual deployment parameters from the deployment parameters corresponding to the rotation direction of the multi-aircraft conflict resolution according to the principle of taking the largest one; The UAV adjusts its heading at the maximum angular velocity according to the rotation direction of the multi-machine conflict resolution obtained and the actual rotation angle, and maintains the initial speed and uniform flight until the flight distance of the UAV reaches the actual obstacle avoidance flight distance, thereby realizing multi-machine dynamic conflict resolution; the method for calculating single-machine conflict resolution based on the maneuverability parameters of the UAV is as follows: Define the initial position of the drone as A and the initial speed as V A_0 ; The initial position of the target aircraft is O, the radius of the safety circle is R, and the flight speed is V0; the initial distance between the UAV and the target aircraft is L AO ; According to the relative velocity vector between the UAV and the target aircraft and the safety circle of the target aircraft, determine the release point position B' corresponding to the counterclockwise direction and the release point position C' corresponding to the clockwise direction; According to the following formula, the rotation angle θ and obstacle avoidance flight distance L of the drone corresponding to the counterclockwise and clockwise directions are calculated. AD And reach obstacle avoidance flight distance L AD The required obstacle avoidance flight time T' total , the formula is: ||V A_2 || / sinα=||-V0|| / sinδ; ||V A_2 ||=||V A_0 ||; V R_2 =V A_2 -V0; δ=arcsin(||-V0||·sinα / ||V A_2 ||); θ = δ - β; L AD =||V A_0 ||·T’ total ; Where V A_2 V is the velocity vector of the drone after rotating at an angle θ; R_2 is the relative velocity vector of the UAV with respect to the target aircraft after the UAV rotates by an angle θ; The relative velocity vector of the drone avoiding potential aircraft, when rotating counterclockwise When rotating clockwise, α is -V0 and The angle between them; β is the velocity vector V A_0 With vector The angle between the velocity vector V A_2 With V R_2 When the drone rotates counterclockwise, 0<θ<90°; when the drone rotates clockwise, -90°<θ<0; Get the rotation angle θ of the drone and the obstacle avoidance flight time T' of the drone total After that, the maximum angular velocity ω of the drone is used to determine whether the drone can be released successfully by rotating counterclockwise or clockwise. If θ≤ω·T' total , then the drone can be released successfully, if θ>ω·T' total , the drone cannot be freed successfully.

6. The method according to claim 5, characterized in that The step of selecting a rotation direction as the rotation direction for multi-machine conflict resolution according to the consistency principle and the safety principle includes: After comparing the calculation results of single-aircraft conflict resolution of all potential collision aircraft, if there is only one rotation direction that can successfully resolve the UAV from all potential collision aircraft, then this rotation direction is selected as the rotation direction for multi-aircraft conflict resolution; After comparing the single-aircraft conflict resolution calculation results obtained by all potential collision aircraft, if both rotation directions can successfully free the UAV from all potential collision aircraft, the safer rotation direction of the UAV with respect to the potential collision aircraft is determined based on the relative velocity vector between the UAV and the potential collision aircraft and the relative position of the safety circle of the potential collision aircraft, and is used as the preferred rotation direction; The preferred rotation directions of the UAVs for each potential collision aircraft are compared, and a rotation direction is selected from the preferred rotation directions as the rotation direction for multi-aircraft conflict resolution based on the consistency principle and the safety principle.

7. The method according to claim 6, characterized in that The comparing the preferred rotation directions of the UAVs for each potential collision aircraft, and selecting a rotation direction from the preferred rotation directions as the rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle, comprises: If the preferred rotation directions of the UAVs for each potential collision aircraft are consistent, the preferred rotation direction is selected as the rotation direction for multi-aircraft conflict resolution; If the preferred rotation directions of the UAVs for each potential collision aircraft are inconsistent, the longest obstacle avoidance flight times corresponding to the two rotation directions are compared, and the rotation direction corresponding to the smaller value is selected as the rotation direction for multi-aircraft conflict resolution based on the safety principle.

8. The method according to claim 6, characterized in that The comparing the preferred rotation directions of the UAVs for each potential collision flight, and selecting a rotation direction from the preferred rotation directions as the rotation direction for multi-aircraft conflict resolution according to the consistency principle and the safety principle, includes: If the preferred rotation directions of the UAVs for each potential collision aircraft are consistent, the preferred rotation direction is selected as the rotation direction for multi-aircraft conflict resolution; If the preferred rotation direction of the UAV for each potential collision aircraft is inconsistent, then for each potential collision aircraft, the distance between the UAV and the potential collision aircraft at a preset time during the obstacle avoidance flight of the UAV based on the counterclockwise direction and the clockwise direction is calculated respectively, and the distance is used as the danger distance; the preset time is the time when the relative velocity vector between the UAV and the potential collision aircraft points to the center point of the potential collision aircraft; Compare the danger distances between the UAVs corresponding to the counterclockwise direction and each potential collision aircraft, and select the minimum value as the minimum danger distance in the counterclockwise direction; compare the danger distances between the UAVs corresponding to the clockwise direction and each potential collision aircraft, and select the minimum value as the minimum danger distance in the clockwise direction; The minimum danger distance in the counterclockwise direction is compared with the minimum danger distance in the clockwise direction, and the rotation direction corresponding to the larger value is selected as the rotation direction for multi-machine conflict resolution according to the safety principle.

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