Unmanned aerial vehicle offline conflict resolution method based on reachable time-space domain

Abstract

The invention provides an unmanned aerial vehicle offline conflict resolution method based on a reachable time-space domain. The method comprises the following steps: acquiring initial flight plan information of each unmanned aerial vehicle in a local space domain; the initial flight plan information comprises a route starting point, a route ending point and flight speed information; according to the obtained initial flight plan information, detecting whether space-time conflicts exist among the flight routes of the unmanned aerial vehicles; the conflict condition comprises an existing conflict and a potential conflict; based on the reachable time-space domain of the unmanned aerial vehicle, performing safety separation constraint analysis according to the initial flight plan information and the conflict condition, generating a route re-planning strategy, and adjusting the flight speed and / or course of the route of the unmanned aerial vehicle according to the route re-planning strategy; the initial plan of the unmanned aerial vehicle is considered when the route re-planning strategy of the unmanned aerial vehicle is generated, so that the deviation between the actual flight plan and the initial plan of the unmanned aerial vehicle is minimized, the influence on the task executed by the unmanned aerial vehicle and additional consumption are reduced, and the method can be widely applied to the technical field of unmanned aerial vehicles.

Description

Technical Field

[0001] This application belongs to the field of unmanned aerial vehicle (UAV) technology, and in particular relates to an offline conflict resolution method for UAVs based on reachable spatiotemporal domain. Background Technology

[0002] With the rapid development of drone technology, it has been widely and deeply applied in logistics delivery, agricultural monitoring, security inspection, and geographic surveying. The efficiency, flexibility, and cost-effectiveness of drones have made them a powerful tool for various industries, driving innovation and development in related sectors. However, with the dramatic increase in the number of drone applications, the contradiction between limited airspace resources and ever-growing flight demands has become increasingly acute. This contradiction not only limits the further development of drones but also makes them more likely to fly close to each other during missions, posing a serious threat to drone flight safety. Traditional air traffic management methods have limitations in design concepts and technical means, failing to meet the safety coordination requirements of large-scale and high-frequency flight operations. Therefore, to ensure the safety and efficiency of drone flights, it is urgent to design a more effective and intelligent air traffic management mechanism. This mechanism can coordinate and optimize large-scale drone flight plans, generating flight plans that meet mission requirements and are conflict-free. This patent aims to solve the spatiotemporal conflicts existing in the initial flight plans of large-scale drones, appropriately adjusting the initial flight plans to generate a conflict-free flight plan set and minimizing the impact on the original plan.

[0003] Currently, methods for resolving drone flight plan conflicts mainly include strategies such as adjusting takeoff time, speed adjustment, and route replanning. Adjusting drone takeoff time to avoid conflicts is a common offline conflict resolution method. For example, combining the "first-come, first-served" principle with mixed-integer linear programming, optimizing takeoff time adjustments can effectively reduce drone flight plan conflicts. Another method is a task scheduling algorithm based on crossover elimination strategies, utilizing improved ant colony optimization algorithms for multi-path planning, and determining the minimum takeoff delay time by considering all possible combinations of drone takeoff time adjustment strategies. These methods resolve conflicts through time-dimensional optimization; however, adjusting takeoff time directly changes the expected arrival time, thus affecting task execution efficiency. Especially when resolving head-on conflicts with parallel flight paths in opposite directions, significant adjustments to takeoff time may be necessary, leading to a significant increase in operating costs. Furthermore, these methods neglect the optimization potential of the spatial dimension, making them difficult to handle large-scale route conflicts in complex airspace, limiting their widespread adoption in practical applications.

[0004] Adjusting the flight speed of drones to achieve safe spatiotemporal separation is another common conflict resolution strategy. For example, by introducing constrained arrival times and combining them with the A* algorithm, speed allocation can be optimized to solve the four-dimensional conflict-free path planning problem in urban air traffic. Furthermore, methods based on adaptive multi-agent reinforcement learning can resolve conflicts by dynamically adjusting the speed and altitude of drones. The advantage of these methods is that they resolve conflicts without changing the flight path, improving the flexibility of conflict resolution. However, speed adjustment strategies may lead to hovering, causing queuing of subsequent drones in high-density traffic scenarios, significantly increasing energy consumption and operating costs. Moreover, this method also neglects the optimization potential of the spatial dimension, making it difficult to meet the safety and efficiency requirements of drone flight in complex airspace environments.

[0005] Flight route replanning strategies resolve conflicts by adjusting flight direction or path, typically combining path optimization and obstacle avoidance algorithms. For example, multi-agent reinforcement learning-based flight route replanning methods can resolve conflicts in high-density traffic scenarios through trajectory adjustment. However, this method is highly dependent on the initial flight plan; if the initial plan is poorly designed, frequent fine-tuning of the replanning strategy is required. Data-driven conflict resolution generators automatically generate conflict resolution schemes by analyzing historical flight data, indirectly supporting flight route replanning. However, this method may introduce new conflicts in complex or dynamic environments, reducing the reliability of conflict resolution. Furthermore, an improved fractal search algorithm combined with a two-level optimization model and a risk assessment framework can optimize predefined four-dimensional routes to avoid conflicts. However, this method has high computational complexity, making it difficult to process in real-time, especially in large-scale UAV scenarios. Summary of the Invention

[0006] The purpose of this invention is to at least partially solve one of the technical problems existing in the prior art. This invention provides an offline conflict resolution method for unmanned aerial vehicles based on reachable spatiotemporal domain. This application provides an offline UAV conflict resolution method based on reachable spatiotemporal domain, the method comprising: Acquire initial flight plan information for each UAV in a local airspace; the initial flight plan information includes the origin, destination, and flight speed information of the flight path. Based on the obtained initial flight plan information, detect whether there are any spatiotemporal conflicts between the UAV flight paths; the conflicts include existing conflicts and potential conflicts. Based on the reachable space-time domain of the UAV, a safety separation constraint analysis is performed according to the initial flight plan information and conflict situation to generate a route replanning strategy. The flight speed and / or heading of the UAV route are adjusted according to the route replanning strategy.

[0007] Preferably, the method further includes: When there are multiple drone routes, the priority of the drones is determined according to the flight schedule in the initial drone plan, with the drone with the earliest take-off time having the highest priority.

[0008] Preferably, the method further includes: When the drone flight path involves multiple conflict scenarios, calculate the safety separation constraints for each conflict scenario.

[0009] Preferably, for multiple conflicts, The constraints are expressed as follows: (3).

[0010] Preferably, the method further includes: When faced with multiple conflicts The feasible solution region is The intersection of the feasible solution regions corresponding to each conflict involved in the route.

[0011] Preferably, the method further includes: according to The reachability space-time constraints and the aforementioned safe separation constraints will determine The route replanning strategy.

[0012] Preferably, the step of detecting whether there is a spatiotemporal conflict between UAV flight paths based on the obtained initial flight plan information includes: Each drone was defined with Centered on, with radius as circular safety area The maximum flight speed of each drone is ; Let the drones on the two interactive drone routes be denoted as follows: and The starting points are respectively and The flight time periods are respectively and Assuming that each conflict-affected route will employ a route rerouting strategy to resolve the conflict, The newly added waypoints on the route are denoted as drones The reachable spacetime domain is ; hour Compared to The position is recorded as ; Compared to The speed is ; In order to analyze and The relationship between them will exist The starting point of time is denoted as ;remember and The overlap of their flight time periods is ;when When the set is empty, the flight paths of the two UAVs will not conflict in time and space; when When the set is not empty, the flight paths of the two UAVs may have existing or potential conflicts. remember by flight After time and The distance is The conflict boundary conditions are obtained as follows: The discriminant is ;when When the discriminant has two solutions, they are: (1) The existing conflict is defined as: when the drone flies according to the initial flight plan, and The distance will be less than The situation is represented as and ; Potential conflict is defined as: when a drone flies according to its initial flight plan, and The distance will not be less than This situation can be represented as... and or However, if their flight plans are improperly adjusted, when the drones fly according to the adjusted flight plans, and The distance may be less than Potential conflicts can turn into existing conflicts.

[0013] Preferably, the method for generating a route replanning strategy based on the reachable spatiotemporal domain of the UAV, according to the initial flight plan information and conflict situation, involves performing a safety separation constraint analysis, including: definition by In time period The flight segment is a relative flight segment. The starting point of this segment is The destination is ;definition In order to obtain Safety separation constraints, passing through point and Make respectively The tangents are denoted as follows: , , and ;So The safety separation constraint can be represented by the half-planes corresponding to these four tangents; let be... The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is ;So Safety separation constraints can be provided by , , , express; For existing conflict situations, the safe separation constraint is: ; For potential conflict scenarios, its safe separation constraints and and besides It is related to the relationship, when At that time, its safe separation constraint ;when At that time, safety separation constraint ; Under the premise of satisfying the reachability space-time constraints and the safety separation constraints, in order to ensure air traffic efficiency and reduce route replanning costs, the objective function of conflict resolution is to minimize additional flight costs. The objective function is defined as follows: (2) in, These are the weighting coefficients.

[0014] Beneficial technical effects of the present invention: This invention discloses an offline conflict resolution method for unmanned aerial vehicles (UAVs) based on reachable spatiotemporal domain, comprising: acquiring initial flight plan information of UAVs in a local airspace; determining a priority sequence of UAVs based on the information; detecting spatiotemporal conflicts between UAV routes based on the acquired information; performing reachable spatiotemporal domain and safety separation constraint analysis based on the acquired information and conflict status; calculating the intersection of reachable spatiotemporal domain constraints and safety separation constraints of each conflict when the UAV route faces multiple conflict situations; generating a route replanning strategy for the UAV based on the spatiotemporal reachable domain constraints, safety separation constraints, and objective function obtained from the analysis; updating the UAV route according to the route replanning strategy; selecting the next priority UAV route, repeating the above analysis, and updating the UAV route; repeating the above process until the lowest priority UAV route is updated. This invention considers the initial flight plan of the UAV when generating the route replanning strategy, minimizing the deviation between the actual flight plan and the initial plan, reducing the impact on the tasks performed by the UAV and the additional consumption, and can be widely applied in the field of UAV technology. Attached Figure Description

[0015] Figure 1 This is an example of a drone in this invention. A schematic diagram of the reachable spatiotemporal domain constrained by the arrival time; Figure 2 This is an embodiment of the present invention. With relative speed During flight and A schematic diagram of distance changes; Figure 3 This is an example of a conflict situation in the embodiments of the present invention. A schematic diagram of the feasible region; Figure 4 In the embodiments of the present invention, when In the event of potential conflict A schematic diagram of the feasible region; Figure 5 In the embodiments of the present invention, when In the event of potential conflict A schematic diagram of the feasible region; Figure 6 This is a flowchart of a multi-UAV conflict resolution algorithm based on reachability spatiotemporal domain and geometric analysis in an embodiment of the present invention. Detailed Implementation

[0016] This invention provides an offline conflict resolution method for unmanned aerial vehicles (UAVs) based on reachability spatiotemporal domain, applicable to UAVs, comprising the following steps: Acquire initial flight plan information for each UAV in a local airspace; the initial flight plan information includes the origin, destination, and flight speed information of the flight path. Based on the obtained initial flight plan information, detect whether there are any spatiotemporal conflicts between the UAV flight paths; the conflicts include existing conflicts and potential conflicts. Based on the reachable space-time domain of the UAV, a safety separation constraint analysis is performed according to the initial flight plan information and conflict situation to generate a route replanning strategy. The flight speed and / or heading of the UAV route are adjusted according to the route replanning strategy.

[0017] Among them, the initial flight plan of the UAV is taken into account when generating the route replanning strategy, so as to minimize the deviation between the actual flight plan of the UAV and the initial flight plan.

[0018] Furthermore, the step of detecting whether there are spatiotemporal conflicts between UAV flight paths based on the obtained initial flight plan information includes: Each drone was defined with Centered on, with radius as circular safety area The maximum flight speed of each drone is ; Let the drones on the two interactive drone routes be denoted as follows: and The starting points are respectively and The flight time periods are respectively and Assuming that each conflict-affected route will employ a route rerouting strategy to resolve the conflict, The newly added waypoints on the route are denoted as drones The reachable spacetime domain is ; hour Compared to The position is recorded as ; Compared to The speed is ; In order to analyze and The relationship between them will exist The starting point of time is denoted as ;remember and The overlap of their flight time periods is ;when When the set is empty, the flight paths of the two UAVs will not conflict in time and space; when When the set is not empty, the flight paths of the two UAVs may have existing or potential conflicts. remember by flight After time and The distance is The conflict boundary conditions can be obtained as follows: The discriminant is ;when When the discriminant has two solutions, they are: (1) The existing conflict is defined as: when the drone flies according to the initial flight plan, and The distance will be less than This situation can be represented as... and ; The potential conflict is defined as: when the drone flies according to the initial flight plan, and The distance will not be less than This situation can be represented as... and or However, if their flight plans are improperly adjusted, when the drones fly according to the adjusted flight plans, and The distance may be less than Potential conflicts can turn into existing conflicts.

[0019] definition by In time period The flight segment is a relative flight segment. The starting point of this segment is The destination is ;definition In order to obtain Safety separation constraints, passing through point and Make respectively The tangents are denoted as follows: , , and ;So The safety separation constraint can be represented by the half-planes corresponding to these four tangents; let be... The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is ;So Safety separation constraints can be provided by , , , express; 1) For existing conflict situations, the safe separation constraint is: ; 2) For potential conflict situations; its safe separation constraints and and besides It is related to the relationship, when At that time, its safe separation constraint ;when At that time, safety separation constraint .

[0020] Under the premise of satisfying the reachability space-time constraints and the safety separation constraints, in order to ensure air traffic efficiency and reduce route replanning costs, the objective function of conflict resolution is to minimize additional flight costs. The objective function is defined as follows: (2) in These are the weighting coefficients.

[0021] Furthermore, the UAV offline conflict resolution method based on reachable spatiotemporal domain also includes the following steps: When there are multiple drone routes, the priority of the drones is determined according to the flight schedule in the initial drone plan, with the drone with the earliest take-off time having the highest priority.

[0022] Furthermore, when the UAV flight path involves multiple conflict scenarios, the safety separation constraints for each conflict scenario are calculated; for multiple conflicts, The constraints can be expressed as: (3) When faced with multiple conflicts The feasible solution region is The intersection of the feasible solution regions corresponding to each conflict involved in the route; according to The reachability space-time constraints and the aforementioned safe separation constraints can be determined. The route replanning strategy.

[0023] Example 1 like Figure 6 As shown, this embodiment provides an offline conflict resolution method for UAVs based on reachable spatiotemporal domain, applied to UAVs, including the following steps: S1. Obtain the initial flight plan information of the UAV in the local airspace; the initial flight plan information includes the starting point, ending point and flight speed information of the route; determine the priority sequence of the UAV based on the above information; S2. Detect whether there are spatiotemporal conflicts between the obtained information and other drone flight paths; the conflicts include existing conflicts and potential conflicts. S3. Based on the obtained information and conflict situation, perform reachability spatiotemporal domain and safety separation constraint analysis; when the UAV route faces multiple conflict situations, calculate the intersection of reachability spatiotemporal domain constraints and safety separation constraints of each conflict; S4. Based on the spatiotemporal reachability constraints, safety separation constraints, and objective function obtained from the analysis, generate a flight path replanning strategy for the UAV; update the UAV flight path according to the flight path replanning strategy. S5. Select the next priority drone route, repeat the above analysis and update the drone route; repeat the above process until the lowest priority drone route has been updated. This invention proposes an offline UAV conflict resolution method based on reachable spatiotemporal domain. Addressing the conflict detection problem between initial UAV plans, this method models the UAV flight trajectory as a continuous function of time through continuous spatiotemporal domain modeling. It describes the distance change relationship between two UAVs based on their relative speed and detects whether a conflict has occurred by calculating the distance between the two UAVs at each moment. During conflict resolution, the conflict detection results are analyzed based on geometric analysis, and the safe separation constraints between UAVs are accurately determined by combining the reachable spatiotemporal domain of the UAVs. Then, a nonlinear optimization model is constructed to minimize the additional flight cost introduced by conflict resolution while ensuring task execution efficiency, transforming the conflict resolution problem into a mathematical optimization problem. To further improve computational efficiency and adapt to the needs of multi-UAV conflict resolution, this method introduces a priority allocation mechanism based on the "first-come, first-served" principle. By sorting UAV segments by start time, the conflict resolution needs of high-priority UAV segments are processed first, proposing a multi-UAV offline conflict resolution algorithm based on the reachable spatiotemporal domain model and geometric analysis.

[0024] The above method will be explained in detail below with reference to the accompanying drawings and specific embodiments.

[0025] I. Description of the problem of offline UAV conflict resolution based on flight path replanning In local airspace, the task of UAV conflict resolution based on route replanning is to detect conflicts in the initial UAV plans and determine the optimal route replanning strategy while ensuring mission efficiency and minimizing the overhead of route replanning. A set of... A collection of drone indexes consisting of drones These drones have predefined flight plans, including routes and schedules, within specific airspace. The start and arrival times of the route are respectively and The coordinates of the start and end points are defined as follows: and Speed ​​is defined as To ensure the flight safety of each drone, this embodiment defines a spherical safety zone for each drone. .in express Time of the first The location of the drone This refers to the safe distance between drones. To generate conflict-free flight plans, the method in this embodiment involves... The route adjustment will be divided into two phases, with the first phase having a speed of [missing information]. The duration is The speed of the second stage is The duration is ,in To ensure the efficiency of the flight plan, we need to ensure that the drone arrives at its destination on time, so , and satisfy: (1) The objective function is to minimize the change in distance and the change in velocity between the two stages, i.e.: (2) in These are the weighting coefficients.

[0026] Therefore, the UAV conflict resolution problem based on route replanning is transformed into a nonlinear optimization problem, which is solved by finding the solution that satisfies the safety separation constraints and the objective function. , and To generate conflict-free flight plans.

[0027] II. Offline UAV Conflict Resolution Based on Flight Route Replanning Step 1. Modeling the reachable spatiotemporal domain of UAVs based on Spacetime Prism Theory (STP) Spacetime prism theory can analyze all possible spatial locations a moving object can occupy within a specific time range, given a starting point, an ending point, and a maximum flight speed. Based on spacetime prism theory, the reachable spacetime domain of a UAV constrained by its arrival time is as follows: Figure 1 As shown.

[0028] This embodiment defines exist The coordinates of the time are ,but , and It can be represented as: (3) in, Indicates from Departure time Locations that can be reached by drones. Indicates time Internal drones can reach The location, among which . yes The reachable spacetime domain. yes Maximum flight speed.

[0029] The projection onto the XY plane is an elliptical region, describing the time interval. Inside The set of physically reachable locations. This can be represented as: (4) Step 2. Conflict Detection To improve the efficiency of conflict detection for large-scale UAV flight paths, this embodiment designs a continuous spatiotemporal conflict detection method, which can determine the safe separation constraints of UAVs through geometric analysis. By aligning takeoff times, the distance between UAVs is analyzed in the same time domain. Two types of conflicts are defined: existing conflicts and potential conflicts. The safe separation constraints differ for each type of conflict.

[0030] Step 2.1 Detection of existing and potential conflicts To reduce unnecessary calculations, this embodiment first filters out pairs of UAVs whose flight times do not overlap. This means that when these UAVs fly according to their initial plans, they will not conflict with each other. This can be described by equation (5): (5) if This indicates and There may be conflicts between them, requiring further analysis of their positional relationships. To improve the efficiency of conflict detection, this embodiment proposes a continuous spatiotemporal conflict detection method. Specifically, conflict detection is the determination of conflicts occurring during flight. and Will the distance between them become too close? To perform collision detection, we need to analyze the drones. and Will the distance between them be less than the safe distance? However, due to and Their takeoff times are usually different, so we first need to synchronize their takeoff times. and Then, we can analyze the changes in distance between them within the same time domain. Since the drone flies at a constant speed in a straight line, we can follow... Directional movement a period of time This gives us a new starting coordinate. .therefore, exist The initial state at time t can be represented as .

[0031] like Figure 2 As shown, through time alignment, we can... and The distance between them is expressed as a function of time. In the local coordinate system O-XY, it is defined as follows: Located at the origin, then Compared to The relative velocity is and Compared to The relative position is Define when With relative speed flight After a period of time, it and The distance is The conflict boundary conditions can be obtained, expressed as: This equation is a quadratic equation in one variable. Its discriminant is: (6) when When the quadratic equation has two solutions... and In other words, when At that time, drones and The distance between them will be less than the safe distance. .

[0032] Based on drones and Regarding the relative positional relationships, this embodiment defines two types of conflicts, namely existing conflicts and potential conflicts. Existing conflicts refer to those occurring when the drone flies according to the initial flight plan. and The distance will be less than This situation can be represented as... and Potential conflict refers to situations where a drone is flying according to its initial flight plan. and The distance will not be less than This situation can be represented as... and or However, if their flight plans are improperly adjusted, when the drones fly according to the adjusted flight plans, and The distance may be less than Potential conflicts can become existing conflicts. Using the rules described above, we can determine whether drones will encounter conflicts when flying according to their initial flight plans, and whether the conflict is an existing or potential conflict.

[0033] Step 2.2 Determine safe separation constraints After determining the conflict type between the two UAVs, safety separation constraints for different conflict types are determined based on the conflict detection process.

[0034] For existing conflict situations, the determination of their safe separation constraints is as follows: Figure 3 As shown. This embodiment defines... With relative speed In time period The flight segment is a relative flight segment. The starting coordinates of this flight segment are The endpoint coordinates are .Adjustment After the speed, Divided into two parts, its endpoint can be represented as: (7) Will Substituting into equation (7) and simplifying, we get equation (8): (8) Therefore, we can know that in the local coordinate system, while ensuring that the arrival time of the drone remains unchanged, adjusting the drone... After reaching a certain speed, the relative flight segment The endpoint coordinates will not change. Definition .like Figure 3 As shown in the shaded area, when When located in the shaded area, both the first and second phases of the relative flight segment are within the safety circle. There are no intersections, meaning there are no conflicts. Therefore, we can analyze... The feasible region is used to determine the safe separation constraints.

[0035] Passing point and Make respectively Tangent, defined and arrive The unit vector is and Define them and tangent and and The angle between the tangents is and Define the rotation matrix as : (9) in The angle of rotation of the rotation matrix.

[0036] Using rotation matrices, we can perform rotation on unit vectors. and Rotate clockwise and counterclockwise respectively and The four tangents are obtained as shown in equation (10): (10) Define the outer normal vectors corresponding to these four tangent lines as follows: , , and They can be represented as: (11) in and It is an orthogonal transformation matrix.

[0037] Therefore, we can obtain the half-plane represented by the four external normal vectors: (12) Define the safety separation constraint as Then, the safe separation constraint for conflict situations is: For the safety separation constraint in potential conflict situations, its safety separation constraint is related to the relative velocity and the external normal vector. and It is related to the relationship. When At that time, its safe separation constraints are as follows: Figure 4 As shown in the shaded area, the safety separation constraint for potential conflict situations can therefore be expressed as... .when At that time, its safe separation constraints are as follows: Figure 5 As shown in the shaded area, the safety separation constraint for potential conflict situations can therefore be expressed as...

[0038] Step 3 Conflict Resolution Step 3.1 Modeling the nonlinear optimization problem Based on the reachability spatiotemporal domain modeling in step 1, we can determine the drone's arrival time constraint. In time interval The set of physically reachable locations. Based on step 2, we can determine whether there are conflicts and their types among the initial UAV plans, and we can determine their safe separation constraints. Therefore, based on the constraints of the above two steps, we can model the UAV conflict resolution problem as a nonlinear optimization problem: (13) st (13a) (13b) (13c) in .

[0039] By solving the above nonlinear optimization problem, we can obtain the UAV. Optimal route replanning and adjustment strategy .

[0040] Step 3.2 Design of Multi-UAV Conflict Resolution Algorithm Based on the first-come, first-served principle, this embodiment designs a multi-UAV conflict resolution algorithm based on reachability spatiotemporal domain and geometric analysis. The algorithm flow is as follows: Figure 6 As shown. We first determine the priority of the drones based on the flight schedule in the initial drone plan, with the drone taking off earliest having the highest priority, defined as... Then the priority sequence of N drones is: From the second priority drone Initially, conflict detection is performed with drones of higher priority according to step 2.1. If a conflict exists, proceed to step 2.2 to determine their safe separation constraints. This continues until all drones with higher priority than itself have been detected. Then, step 3.1 is entered to form a nonlinear optimization problem as shown in equation (13). Solving the nonlinear optimization problem yields the optimal route replanning strategy. Then, update the drone's flight plan. After the update, select the drone with the lowest priority and execute steps 2.1, 2.2, and 3.1 in sequence. Repeat the above process until the drone with the lowest priority completes the above process. The algorithm is then complete, and a conflict-free drone flight plan is obtained.

[0041] Example 2 This invention also provides an electronic device, which includes a processor and a memory. The memory stores at least one instruction, at least one program, a code set, or an instruction set. The at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to achieve the following: Figure 6 This paper presents an offline conflict resolution method for unmanned aerial vehicles (UAVs) based on reachable spatiotemporal domain.

[0042] It is understood that the memory may include random access memory (RAM) or read-only memory. Optionally, the memory may include non-transitory computer-readable storage medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a stored program area and a stored data area, wherein the stored program area may store instructions for implementing an operating system, instructions for at least one function, instructions for implementing the various method embodiments described above, etc.; the stored data area may store data created according to the use of the server, etc.

[0043] A processor may include one or more processing cores. The processor connects to various parts of the server via various interfaces and lines, performing various server functions and processing data by running or executing instructions, programs, code sets, or instruction sets stored in memory, and by accessing data stored in memory. Optionally, the processor may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor may integrate one or more of a Central Processing Unit (CPU) and a modem. The CPU primarily handles the operating system and applications; the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0044] Since this electronic device is the electronic device corresponding to the offline conflict resolution method for unmanned aerial vehicles based on reachable spatiotemporal domain in the embodiments of the present invention, and the principle of solving the problem by this electronic device is similar to that of this method, the implementation of this electronic device can refer to the implementation process of the above method embodiments, and the repeated parts will not be described again.

[0045] Example 3 This embodiment provides a drone equipped with a device for performing tasks such as... Figure 6 The electronic device described in the method. Specifically, the drone can be a fixed-wing drone, a rotary-wing aircraft, or other types of drones.

[0046] Example 4 This invention also provides a computer-readable storage medium storing at least one instruction, at least one program, a code set, or an instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to achieve the following: Figure 6 This paper presents an offline conflict resolution method for unmanned aerial vehicles (UAVs) based on reachable spatiotemporal domain.

[0047] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compactdisc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium capable of carrying or storing data.

[0048] Since this storage medium is the storage medium corresponding to the offline conflict resolution method for unmanned aerial vehicles based on reachable spatiotemporal domain in an embodiment of the present invention, and the principle of the storage medium in solving the problem is similar to that of the method, the implementation of this storage medium can refer to the implementation process of the above method embodiment, and the repeated parts will not be described again.

[0049] Example 5 In some possible implementations, various aspects of the methods of the embodiments of the present invention can also be implemented as a program product comprising program code that, when run on a computer device, causes the computer device to perform the steps of an offline UAV conflict resolution method based on an reachable spatiotemporal domain according to various exemplary embodiments of this application as described above. The executable computer program code or "code" used to perform the various embodiments can be written in high-level programming languages ​​such as C, C++, C#, Smalltalk, Java, JavaScript, Visual Basic, Structured Query Language (e.g., Transact-SQL), Perl, or in various other programming languages.

Claims

1. A method for offline conflict resolution of unmanned aerial vehicles (UAVs) based on reachability in spatiotemporal domain, characterized in that, The method includes: Acquire initial flight plan information for each UAV in a local airspace; the initial flight plan information includes the origin, destination, and flight speed information of the flight path. Based on the obtained initial flight plan information, detect whether there are any spatiotemporal conflicts between the UAV flight paths; the conflicts include existing conflicts and potential conflicts. Based on the reachable space-time domain of the UAV, a safety separation constraint analysis is performed according to the initial flight plan information and conflict situation to generate a route replanning strategy. The flight speed and / or heading of the UAV route are adjusted according to the route replanning strategy.

2. The method according to claim 1, characterized in that, The method further includes: When there are multiple drone routes, the priority of the drones is determined according to the flight schedule in the initial drone plan, with the drone with the earliest take-off time having the highest priority.

3. The method according to claim 2, characterized in that, The method further includes: When the drone flight path involves multiple conflict scenarios, calculate the safety separation constraints for each conflict scenario.

4. The method according to claim 3, characterized in that, For multiple conflicts, The constraints are expressed as follows: （3）。 5. The method according to claim 4, characterized in that, The method further includes: When faced with multiple conflicts The feasible solution region is The intersection of the feasible solution regions corresponding to each conflict involved in the route.

6. The method according to claim 5, characterized in that, The method further includes: according to The reachability space-time constraints and the aforementioned safe separation constraints will determine The route replanning strategy.

7. The method according to claim 1, characterized in that, The step of detecting whether there are spatiotemporal conflicts between UAV flight paths based on the obtained initial flight plan information includes: Each drone was defined with Centered on, with radius as circular safety area The maximum flight speed of each drone is ; Let the drones on the two interactive drone routes be denoted as follows: and The starting points are respectively and The flight time periods are respectively and Assuming that each conflict-affected route will employ a route rerouting strategy to resolve the conflict, The newly added waypoints on the route are denoted as drones The reachable spacetime domain is ; hour Compared to The position is recorded as ; Compared to The speed is ; In order to analyze and The relationship between them will exist The starting point of time is denoted as ;remember and The overlap of their flight time periods is ;when When the set is empty, the flight paths of the two UAVs will not conflict in time and space; when When the set is not empty, the flight paths of the two UAVs may have existing or potential conflicts. remember by flight After time and The distance is The conflict boundary conditions are obtained as follows: The discriminant is ;when When the discriminant has two solutions, they are: （1） The existing conflict is defined as: when the drone flies according to the initial flight plan, and The distance will be less than The situation is represented as and ; Potential conflict is defined as: when a drone flies according to its initial flight plan, and The distance will not be less than This situation can be represented as... and or However, if their flight plans are improperly adjusted, when the drones fly according to the adjusted flight plans, and The distance may be less than Potential conflicts can turn into existing conflicts.

8. The method according to claim 7, characterized in that, The UAV-based reachable spatiotemporal domain, based on initial flight plan information and conflict conditions, performs safety separation constraint analysis to generate a route replanning strategy, including: definition by In time period The flight segment is a relative flight segment. The starting point of this segment is The destination is ;definition In order to obtain Safety separation constraints, passing through point and Make respectively The tangents are denoted as follows: , , and ;So The safety separation constraint can be represented by the half-planes corresponding to these four tangents; let be... The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is , The corresponding one does not include The half-plane is ;So Safety separation constraints can be provided by , , , express; For existing conflict situations, the safe separation constraint is: ; For potential conflict scenarios, its safe separation constraints and and besides It is related to the relationship, when At that time, its safe separation constraint ;when At that time, safety separation constraint ; Under the premise of satisfying the reachability space-time constraints and the safety separation constraints, in order to ensure air traffic efficiency and reduce route replanning costs, the objective function of conflict resolution is to minimize additional flight costs. The objective function is defined as follows: （2） in, These are the weighting coefficients.

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