EVTOL conflict detection and collision avoidance decision method

Abstract

The invention belongs to the technical field of aircraft navigation guidance and control. The invention provides an eVTOL conflict detection and collision avoidance decision method. According to the embodiment of the invention, whether conflicts occur or not is judged in the horizontal direction and the vertical direction, the conflicts are divided into different levels and priorities according to the conflict time, a more reasonable collision avoidance target and a designed collision avoidance decision can be provided for a collision avoidance strategy, and the horizontal collision avoidance strategy and the vertical collision avoidance strategy are adaptively adopted according to the conflict levels, so that the collision avoidance efficiency is improved. And different maneuvering strategies are adaptively adopted according to the collision avoidance time, so that the optimal collision avoidance strategy with small influence and short time is selected. According to the method, the eVTOL can effectively identify possible threats in the airspace in a complex flight environment, and a high-quality collision avoidance strategy with relatively high adaptability is provided.

Description

Technical Field

[0001] The disclosed embodiments relate to the technical field of aircraft navigation, guidance and control, and in particular to an eVTOL conflict detection and collision avoidance decision method. Background Art

[0002] Although the development of eVTOL collision avoidance systems is still a new project, countries around the world have long conducted in-depth research on large aircraft collision avoidance issues. From the initial secondary radar, air traffic alert, TCAS to the new generation of airborne collision avoidance system ACASX (Airborne Collision Avoidance System X), the algorithms used in these generations of large aircraft collision avoidance systems are based on geometric rules to predict the approach time and approach distance between aircraft that may conflict in the possible airspace, and then give traffic alerts (TA) and decision alerts (RA) to guide pilots to maintain or increase vertical separation. Therefore, the thinking about aircraft collision avoidance is also in line with the idea and model establishment of large aircraft aerial detection of situational threats.

[0003] The definition of the clear zone is crucial to the establishment of the collision avoidance model. It is the basis for realizing the self-separation (SS) function of the aircraft to avoid collision. In realizing the collision avoidance (CA) function of the aircraft, there are three key links: situation awareness, conflict prediction and conflict resolution. Many Chinese and foreign scholars have conducted research on this. Through situation awareness and conflict prediction, it is necessary to obtain more accurate flight status information of other aircraft in the airspace in the future. The main methods currently used are probability analysis and geometric analysis.

[0004] However, the probability analysis method cannot meet the requirements of real-time prediction because the amount of calculation in practical applications is too large. The geometric analysis method does not meet the actual situation because the horizontal separation standard is much greater than the vertical separation standard in the current safety separation standard. Therefore, the cylindrical model is used to obtain better results; but the single collision risk model cannot best reflect the process from approach to collision of aircraft.

[0005] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0006] It should be noted that this section is intended to provide background or context for the technical solutions of the present disclosure stated in the claims. The description herein is not admitted to be prior art by virtue of being included in this section. Summary of the invention

[0007] The purpose of the embodiments of the present disclosure is to provide an eVTOL conflict detection and collision avoidance decision method, thereby overcoming one or more problems caused by the limitations and defects of the related art at least to a certain extent.

[0008] According to an embodiment of the present disclosure, an eVTOL conflict detection and collision avoidance decision method is provided, the method comprising: Using the own aircraft to obtain target position information and target speed information of each target aircraft, and converting the target position information and the target speed information into the coordinate system where the own aircraft is located, so as to obtain the relative position and relative speed of the own aircraft and each of the target aircraft; Performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the own aircraft conflicts with each of the target aircraft, and if so, calculating the conflict time; The conflict time is graded to obtain a conflict level; wherein the conflict level includes a prevention level conflict, a correction level conflict and a collision avoidance level conflict; According to the conflict level, a number of corresponding initial collision avoidance decisions are determined, and in combination with the maneuverability characteristic information of the own aircraft, collision avoidance times of all the initial collision avoidance decisions are obtained, and the optimal collision avoidance decision is selected according to the collision avoidance times.

[0009] Further, the step of using the own aircraft to obtain target position information and target speed information of each target aircraft, and converting the target position information and the target speed information into the coordinate system where the own aircraft is located, so as to obtain the relative position and relative speed of the own aircraft and each of the target aircraft, includes: Using the own aircraft to obtain the target position information and the target speed information of each target aircraft; The coordinate system is established by taking the aircraft as the origin of the coordinate system, the speed direction of the aircraft as the x-axis, the vertical upward direction as the z-axis, and the y-axis as determined by the right-hand rule; The target position information and the target speed information are converted into the coordinate system to obtain the relative position and the relative speed of the own aircraft and each of the target aircraft.

[0010] Further, performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the own aircraft conflicts with each of the target aircraft, and if so, calculating the conflict time, includes: The relative horizontal distance between the own aircraft and each of the target aircraft is obtained according to the relative position and relative vertical distance , according to the relative speed, the relative horizontal speed between the own aircraft and each of the target aircraft is obtained and relative vertical velocity ; The relative horizontal distance Horizontal distance threshold The values ​​are compared; If the relative horizontal distance Greater than the horizontal distance threshold , then determine the relative horizontal speed Whether it is directed to the clear airspace of the target aircraft, if so, it means that a horizontal conflict will occur, if not, it means that a horizontal conflict will not occur; If the relative horizontal distance Less than or equal to the horizontal distance threshold , it means that a horizontal conflict has occurred; According to the direction of the relative speed, the position of entering the clear airspace is calculated to obtain the distance from the aircraft to the intrusion point. , combined with the relative horizontal velocity , get the horizontal conflict time ; The relative vertical distance Vertical distance threshold Compare; If the relative vertical distance Greater than the vertical distance threshold , then determine the relative vertical speed and the relative vertical distance Are the directions opposite? If yes, it means that vertical conflict will occur; if no, it means that no conflict will occur; If the relative vertical distance Less than or equal to the vertical distance threshold , it means that vertical conflict has occurred; According to the relative vertical velocity and the relative vertical distance , get the vertical conflict time ; Conflict time according to the level and the vertical conflict time , get the conflict time .

[0011] Further, the relative horizontal speed is determined The expression of the clear airspace pointing to the target aircraft is:

[0012] in, Indicates the direction of the target aircraft relative to the own aircraft. represents the direction of the relative horizontal velocity, Indicates the relative horizontal distance between the own aircraft and the target aircraft. Indicates the radius of the clear airspace; The level conflict time The expression is:

[0013] in, represents the relative horizontal speed, Indicates the distance from the aircraft to the invasion point; The vertical conflict time The expression is:

[0014] in, is the relative vertical distance.

[0015] Furthermore, if both horizontal and vertical conflicts occur at the same time, it means that a conflict will occur, and the conflict time is .

[0016] Furthermore, the step of classifying the conflict time to obtain the conflict level includes: If the conflicting time Less than or equal to the first time threshold , and is greater than 0, it is the collision avoidance level conflict; If the conflicting time Less than or equal to the second time threshold , and is greater than the first time threshold , then it is the correction level conflict; If the conflicting time Greater than the second time threshold , then it is the prevention-level conflict; If the conflicting time If it is equal to 0, it means a conflict has occurred.

[0017] Furthermore, the priority order of the conflict levels is: The collision avoidance level conflicts, the correction level conflicts and the prevention level conflicts.

[0018] Further, a plurality of initial collision avoidance decisions corresponding to the conflict level are determined, and collision avoidance times of all the initial collision avoidance decisions are obtained in combination with the maneuverability characteristic information of the own aircraft, and the step of selecting the optimal collision avoidance decision according to the collision avoidance time includes: If it is determined to be the prevention-level conflict, the strategy of adjusting the horizontal speed is adopted, and the horizontal adjustment time for adjusting the horizontal speed is calculated in combination with the maneuvering characteristic information of the aircraft. , if the level adjustment time Less than the conflict time , then the horizontal speed maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy, otherwise the heading maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy; If it is determined to be the correction level conflict or the collision avoidance level conflict, the horizontal collision avoidance time is calculated respectively in combination with the maneuverability characteristic information of the own aircraft. and vertical collision avoidance time , select the direction with short collision avoidance time as the optimal collision avoidance strategy.

[0019] Further, the horizontal adjustment time of adjusting the horizontal speed The expression is:

[0020] in, Indicates the speed direction of the aircraft. Indicates the speed direction of the target aircraft, Indicates the speed of the target aircraft. Indicates the direction of the target aircraft relative to the own aircraft. Indicates the relative horizontal distance between the own aircraft and the target aircraft. represents the radius of the clear space, To adjust the horizontal speed, Indicates the maximum horizontal acceleration of the aircraft; The horizontal collision avoidance time The expression is:

[0021] in, Indicates the speed direction of the aircraft. Indicates the speed direction of the target aircraft, Indicates the speed of the target aircraft. Indicates the direction of the target aircraft relative to the own aircraft. Indicates the relative horizontal distance between the own aircraft and the target aircraft. represents the radius of the clear space, To adjust the speed direction of the aircraft, Indicates the maximum yaw rate of the aircraft; The vertical collision avoidance time The expression is:

[0022] in, represents the relative vertical velocity, Indicates the maximum vertical acceleration of the aircraft.

[0023] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects: In the embodiment of the present disclosure, through the above-mentioned eVTOL conflict detection and collision avoidance decision method, on the one hand, first detect the airspace where the aircraft is located, the three-dimensional position and speed information of the target aircraft, establish a coordinate system with the aircraft as the coordinate origin, and calculate the position and speed information of other target aircraft relative to the aircraft; then use the distance and time method to perform conflict detection, calculate the conflict time, and divide the conflict priority; the aircraft with the highest conflict priority and the highest threat will preferentially select the optimal collision avoidance method according to the collision avoidance strategy. On the other hand, by judging whether a conflict will occur in the horizontal and vertical directions, and dividing the conflict into different levels and priorities according to the conflict time, it is possible to provide a more reasonable collision avoidance target for the collision avoidance strategy, and the designed collision avoidance decision, according to the conflict level, adaptively adopt horizontal and vertical collision avoidance strategies, and adaptively adopt different maneuvering strategies according to the collision avoidance time, so as to select the optimal collision avoidance strategy with small impact and short time. It can enable eVTOL to effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0025] Figure 1 A step diagram showing an eVTOL conflict detection and collision avoidance decision method in an exemplary embodiment of the present disclosure; Figure 2 A schematic diagram showing the eVTOL conflict detection process and conflict division principle in an exemplary embodiment of the present disclosure is shown; Figure 3 A schematic diagram of a collision avoidance strategy in an exemplary embodiment of the present disclosure is shown; Figure 4 A specific flow chart of an eVTOL conflict detection and collision avoidance decision method in an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0026] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the disclosure will be more comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0027] In addition, the accompanying drawings are only schematic illustrations of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0028] This example embodiment provides an eVTOL conflict detection and collision avoidance decision method. Figure 1 As shown in , the eVTOL conflict detection and collision avoidance decision method may include: step S101 to step S104.

[0029] Step S101: using the own aircraft to obtain target position information and target speed information of each target aircraft, and converting the target position information and the target speed information into the coordinate system where the own aircraft is located, so as to obtain the relative position and relative speed of the own aircraft and each target aircraft; Step S102: performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the own aircraft conflicts with each of the target aircrafts, and if so, calculating the conflict time; Step S103: classifying the conflict time to obtain a conflict level; wherein the conflict level includes a prevention level conflict, a correction level conflict and a collision avoidance level conflict; Step S104: determining a number of corresponding initial collision avoidance decisions according to the conflict level, obtaining collision avoidance times of all the initial collision avoidance decisions in combination with the maneuverability characteristic information of the own aircraft, and selecting the optimal collision avoidance decision according to the collision avoidance times.

[0030] Through the above-mentioned eVTOL conflict detection and collision avoidance decision-making method, on the one hand, the airspace where the aircraft is located, the three-dimensional position and speed information of the target aircraft are first detected, and the coordinate system is established with the aircraft as the coordinate origin to calculate the position and speed information of other target aircraft relative to the aircraft; then the distance and time method is integrated to detect the conflict, calculate the conflict time, and divide the conflict priority; the aircraft with the highest conflict priority and the highest threat will first select the optimal collision avoidance method according to the collision avoidance strategy. On the other hand, by judging whether a conflict will occur in the horizontal and vertical directions, and dividing the conflict into different levels and priorities according to the conflict time, it can provide a more reasonable collision avoidance target for the collision avoidance strategy, and the designed collision avoidance decision, according to the conflict level, the horizontal collision avoidance and vertical collision avoidance strategies are adaptively adopted, and different maneuvering strategies are adaptively adopted according to the collision avoidance time, so as to select the optimal collision avoidance strategy with small impact and short time. It can enable eVTOL to effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability.

[0031] Next, we will refer to Figures 1 to 4 Each step of the above-mentioned eVTOL conflict detection and collision avoidance decision method in this example implementation is described in more detail.

[0032] In step S101, the own aircraft (i.e., the own aircraft) is taken as the coordinate origin, and the own aircraft speed direction is Axis, vertically upward Axis, determined by right-hand rule Axis, establish a coordinate system, and then convert the position information and speed information of other aircraft (i.e. target aircraft) into this coordinate system.

[0033] In step S102, Figure 2 As shown, the conflict detection is: 1) Set the horizontal distance between the host and the target (i.e. relative horizontal distance) and horizontal distance threshold Compare; 2) If the horizontal distance is greater than the horizontal distance threshold, determine whether the relative horizontal speed points to the clear airspace of the target aircraft. If so, it means that a horizontal conflict will occur. Otherwise, it means that a horizontal conflict will not occur. If the horizontal distance is less than or equal to the horizontal distance threshold, it means that a horizontal conflict has occurred.

[0034] If satisfied:

[0035] It means that the relative horizontal speed points to the clear airspace of the target aircraft, where Indicates the direction of the target machine relative to the local machine. represents the direction of the relative horizontal velocity, Indicates the horizontal distance between the host and the target machine. Indicates the radius of the clear airspace; 3) According to the direction of relative speed, calculate the position of entering the clear airspace and obtain the distance from the aircraft to the intrusion point , using the magnitude of the horizontal relative velocity (i.e., relative horizontal velocity) , calculate the horizontal conflict time .

[0036] Horizontal conflict time The calculation method is:

[0037] in, Indicates the direction of the target machine relative to the local machine. represents the direction of the relative horizontal velocity, Indicates the horizontal distance between the host and the target machine. represents the radius of the clear space, represents the magnitude of the horizontal relative velocity, Indicates the distance from the machine to the intrusion point.

[0038] 4) Change the vertical distance between the host and the target Vertical distance threshold Compare; 5) If the vertical distance is greater than the vertical distance threshold, determine whether the directions of the relative vertical speed (i.e., relative vertical speed) and the relative vertical distance (i.e., relative vertical distance) are opposite. If so, it indicates that a vertical conflict will occur. Otherwise, it indicates that no conflict will occur. If the relative vertical distance is less than or equal to the vertical distance threshold, it indicates that a vertical conflict has occurred. 6) Based on relative vertical speed and relative vertical distance , calculate the time when vertical conflict occurs ; 7) If both horizontal and vertical conflicts are determined to occur, a conflict will occur and the conflict time is ; In step S103, conflicts are divided into prevention-level conflicts, correction-level conflicts and collision avoidance-level conflicts according to the conflict time. Among the conflicts with the highest priority, the conflicts with the highest threat are avoided first.

[0039] like Figure 2 As shown, the conflict division principle is: if the conflict time Greater than time threshold , then it is a prevention-level conflict. If the conflict time Less than or equal to the time threshold , and greater than the time threshold , then it is a correction level conflict. If the conflict time Less than or equal to the time threshold , and is greater than 0, it is a collision avoidance level conflict. If the conflict time If it is equal to 0, it means a conflict has occurred.

[0040] The order of conflict priority is: collision avoidance conflict > correction conflict > prevention conflict, threat and conflict time Related, conflict time The smaller it is, the greater the threat.

[0041] In step S104, according to different conflict levels, the target aircraft with the highest priority and the greatest threat is selected, and the collision avoidance time of different collision avoidance strategies is determined based on the maneuverability characteristics of the eVTOL, so as to select the optimal collision avoidance strategy; like Figure 3 As shown in the figure, the collision avoidance strategy is: if it is determined to be a preventive-level conflict, a horizontal collision avoidance strategy is adopted. On the principle of not changing the original flight path as much as possible, the time required to adjust the horizontal speed is first calculated based on the eVTOL maneuvering characteristics. , if less than the conflict time , the speed control maneuver strategy is used first, otherwise the heading adjustment strategy is used; if it is determined to be a correction level conflict or a collision avoidance level conflict, the horizontal collision avoidance time is calculated according to the eVTOL maneuver characteristics. and vertical collision avoidance time , select the one with short collision avoidance time as the optimal collision avoidance strategy.

[0042] The time required to adjust the horizontal speed is calculated as:

[0043] in Indicates the speed direction of the machine. Indicates the speed direction of the target machine. Indicates the speed of the target machine. Indicates the direction of the target machine relative to the local machine. Indicates the horizontal distance between the host and the target machine. represents the radius of the clear space, To adjust to the horizontal speed, Indicates the maximum horizontal acceleration of the aircraft.

[0044] Horizontal collision avoidance time The calculation method is:

[0045] in Indicates the speed direction of the machine. Indicates the speed direction of the target machine. Indicates the speed of the target machine. Indicates the direction of the target machine relative to the local machine. Indicates the horizontal distance between the host and the target machine. represents the radius of the clear space, To adjust the speed direction to the local speed, Indicates the maximum yaw rate of the aircraft.

[0046] Vertical collision avoidance time The calculation method is ,in represents the relative vertical speed, Indicates the maximum vertical acceleration of the aircraft.

[0047] like Figure 4 The figure shows a specific flow chart of this application.

[0048] Through the above-mentioned eVTOL conflict detection and collision avoidance decision-making method, on the one hand, the airspace where the aircraft is located, the three-dimensional position and speed information of the target aircraft are first detected, and the coordinate system is established with the aircraft as the coordinate origin to calculate the position and speed information of other target aircraft relative to the aircraft; then the distance and time method is integrated to detect the conflict, calculate the conflict time, and divide the conflict priority; the aircraft with the highest conflict priority and the highest threat will first select the optimal collision avoidance method according to the collision avoidance strategy. On the other hand, by judging whether a conflict will occur in the horizontal and vertical directions, and dividing the conflict into different levels and priorities according to the conflict time, it can provide a more reasonable collision avoidance target for the collision avoidance strategy, and the designed collision avoidance decision, according to the conflict level, the horizontal collision avoidance and vertical collision avoidance strategies are adaptively adopted, and different maneuvering strategies are adaptively adopted according to the collision avoidance time, so as to select the optimal collision avoidance strategy with small impact and short time. It can enable eVTOL to effectively identify possible threats in the airspace in a complex flight environment and provide a high-quality collision avoidance strategy with strong adaptability.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0051] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

Claims

1. An eVTOL conflict detection and collision avoidance decision method, characterized in that: The method includes: Using the own aircraft to obtain target position information and target speed information of each target aircraft, and converting the target position information and the target speed information into the coordinate system where the own aircraft is located, so as to obtain the relative position and relative speed of the own aircraft and each of the target aircraft; Performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the own aircraft conflicts with each of the target aircraft, and if so, calculating the conflict time; The conflict time is graded to obtain a conflict level; wherein the conflict level includes a prevention level conflict, a correction level conflict and a collision avoidance level conflict; According to the conflict level, a number of corresponding initial collision avoidance decisions are determined, and in combination with the maneuverability characteristic information of the own aircraft, collision avoidance times of all the initial collision avoidance decisions are obtained, and the optimal collision avoidance decision is selected according to the collision avoidance times.

2. The eVTOL conflict detection and collision avoidance decision method according to claim 1, characterized in that: The step of using the own aircraft to obtain target position information and target speed information of each target aircraft, and converting the target position information and the target speed information into a coordinate system where the own aircraft is located, so as to obtain the relative position and relative speed of the own aircraft and each of the target aircraft, includes: Using the own aircraft to obtain the target position information and the target speed information of each target aircraft; The coordinate system is established by taking the aircraft as the origin of the coordinate system, the speed direction of the aircraft as the x-axis, the vertical upward direction as the z-axis, and the y-axis as determined by the right-hand rule; The target position information and the target speed information are converted into the coordinate system to obtain the relative position and the relative speed of the own aircraft and each of the target aircraft.

3. The eVTOL conflict detection and collision avoidance decision method according to claim 1, characterized in that: The step of performing eVTOL conflict detection according to the relative position and the relative speed to determine whether the own aircraft conflicts with each of the target aircraft, and if so, calculating the conflict time includes: The relative horizontal distance between the own aircraft and each of the target aircraft is obtained according to the relative position and relative vertical distance , according to the relative speed, the relative horizontal speed between the own aircraft and each of the target aircraft is obtained and relative vertical velocity ; The relative horizontal distance Horizontal distance threshold The values ​​are compared; If the relative horizontal distance Greater than the horizontal distance threshold , then determine the relative horizontal speed Whether it is directed to the clear airspace of the target aircraft, if so, it means that a horizontal conflict will occur, if not, it means that a horizontal conflict will not occur; If the relative horizontal distance Less than or equal to the horizontal distance threshold , it means that a horizontal conflict has occurred; According to the direction of the relative speed, the position of entering the clear airspace is calculated to obtain the distance from the aircraft to the intrusion point. , combined with the relative horizontal velocity , get the horizontal conflict time ; The relative vertical distance Vertical distance threshold Compare; If the relative vertical distance Greater than the vertical distance threshold , then determine the relative vertical speed and the relative vertical distance Are the directions opposite? If yes, it means that vertical conflict will occur; if no, it means that no conflict will occur; If the relative vertical distance Less than or equal to the vertical distance threshold , it means that vertical conflict has occurred; According to the relative vertical velocity and the relative vertical distance , get the vertical conflict time ; Conflict time according to the level and the vertical conflict time , get the conflict time .

4. The eVTOL conflict detection and collision avoidance decision method according to claim 1, characterized in that: Determine the relative horizontal speed The expression of the clear airspace pointing to the target aircraft is: in, Indicates the direction of the target aircraft relative to the own aircraft. represents the direction of the relative horizontal velocity, Indicates the relative horizontal distance between the own aircraft and the target aircraft. Indicates the radius of the clear airspace; The level conflict time The expression is: in, represents the relative horizontal speed, Indicates the distance from the aircraft to the invasion point; The vertical conflict time The expression is: in, is the relative vertical distance.

5. The eVTOL conflict detection and collision avoidance decision method according to claim 4, characterized in that: If both horizontal and vertical conflicts occur at the same time, it means a conflict will occur, and the conflict time is .

6. The eVTOL conflict detection and collision avoidance decision method according to claim 4, characterized in that: The step of classifying the conflict time to obtain the conflict level includes: If the conflicting time Less than or equal to the first time threshold , and is greater than 0, it is the collision avoidance level conflict; If the conflicting time Less than or equal to the second time threshold , and is greater than the first time threshold , then it is the correction level conflict; If the conflicting time Greater than the second time threshold , then it is the prevention-level conflict; If the conflicting time If it is equal to 0, it means a conflict has occurred.

7. The eVTOL conflict detection and collision avoidance decision method according to claim 6, characterized in that: The order of priority of the conflict levels is: The collision avoidance level conflicts, the correction level conflicts and the prevention level conflicts.

8. The eVTOL conflict detection and collision avoidance decision method according to claim 7, characterized in that: The step of determining a number of corresponding initial collision avoidance decisions according to the conflict level, combining the maneuverability characteristic information of the own aircraft, obtaining collision avoidance times of all the initial collision avoidance decisions, and selecting the optimal collision avoidance decision according to the collision avoidance times includes: If it is determined to be the prevention-level conflict, the strategy of adjusting the horizontal speed is adopted, and the horizontal adjustment time for adjusting the horizontal speed is calculated in combination with the maneuvering characteristic information of the aircraft. , if the level adjustment time Less than the conflict time , then the horizontal speed maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy, otherwise the heading maneuvering collision avoidance strategy is used as the optimal collision avoidance strategy; If it is determined to be the correction level conflict or the collision avoidance level conflict, the horizontal collision avoidance time is calculated respectively in combination with the maneuverability characteristic information of the own aircraft. and vertical collision avoidance time , select the direction with short collision avoidance time as the optimal collision avoidance strategy.

9. The eVTOL conflict detection and collision avoidance decision method according to claim 8, characterized in that: Adjust the horizontal speed by the horizontal adjustment time The expression is: in, Indicates the speed direction of the aircraft. Indicates the speed direction of the target aircraft, Indicates the speed of the target aircraft. Indicates the direction of the target aircraft relative to the own aircraft. Indicates the relative horizontal distance between the own aircraft and the target aircraft. represents the radius of the clear space, To adjust the horizontal speed, Indicates the maximum horizontal acceleration of the aircraft; The horizontal collision avoidance time The expression is: in, Indicates the speed direction of the aircraft. Indicates the speed direction of the target aircraft, Indicates the speed of the target aircraft. Indicates the direction of the target aircraft relative to the own aircraft. Indicates the relative horizontal distance between the own aircraft and the target aircraft. represents the radius of the clear space, To adjust the speed direction of the aircraft, Indicates the maximum yaw rate of the aircraft; The vertical collision avoidance time The expression is: in, represents the relative vertical velocity, Indicates the maximum vertical acceleration of the aircraft.

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