Horizontal reference path calculation method of eVTOL waiting mode

Abstract

The invention relates to the technical field of eVTOL and the like, and provides a horizontal reference path calculation method for an eVTOL waiting mode, which comprises the following steps: acquiring the position, track angle, ground speed and waiting mode type of the current eVTOL, determining a waiting positioning point according to the acquired information, and constructing an entering track; establishing an auxiliary dividing line by taking the entry edge as a reference to divide the space into four quadrants, and determining an entry path type according to the quadrant where the entry track is located; calling a corresponding path node generation rule to construct an entry section according to the path type, constructing an execution section, and generating an exit section when an end condition is met; in the entering section, the translation distance of the navigational arc is limited and subjected to interference checking, the arc parameter or the position of the waiting point is adjusted if necessary, and finally a complete reference path is formed. According to the method, the dynamic adaptability, geometric coordination and flight safety of path planning are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of electric vertical take-off and landing aircraft, path planning, and more particularly to a method for calculating a horizontal reference path in an eVTOL waiting mode. Background Art

[0002] With the rapid development of Urban Air Mobility (UAM), electric vertical take-off and landing (eVTOL) vehicles are becoming a crucial tool for future short-distance urban transportation. In typical urban airspace operations, eVTOLs often need to hold airborne within designated areas when performing docking, takeoff, landing, or holding missions to avoid route congestion, takeoff and landing resource conflicts, or temporary flight bans. To ensure flight safety and trajectory compliance, eVTOLs must generate a horizontal reference path based on predefined rules and fly in a loop until departure conditions are met. Existing path design methods for eVTOL holding modes often draw inspiration from the holding phase of traditional aircraft, employing fixed trajectory templates (such as standard elliptical or circular orbits) or matching with a library of pre-set paths. This approach lacks flexibility and cannot dynamically generate a customized holding path that meets operational requirements based on the eVTOL's current flight state, such as heading, speed, and entry angle. In addition, some methods ignore the geometric coordination relationship between different trajectory segments in the waiting path configuration, which may lead to discontinuity, non-smoothness or trajectory conflict between the entry path and the waiting path, or even spatial interference between path segments, thereby increasing the complexity of flight control and operational risks.

[0003] In summary, in the existing technology, the path planning technology for the eVTOL waiting mode lacks the ability to dynamically generate waiting path planning based on the real-time flight status of the eVTOL. The path classification method is rough and fails to accurately determine the appropriate entry type based on the entry angle and quadrant relationship. It is difficult to take into account the feasibility of the flight path and the coordination between spatial constraints. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the existing technologies, the present invention provides a horizontal reference path calculation method for the eVTOL waiting mode, which solves the technical problems of the existing technologies such as insufficient flexibility, rough entry path selection, and easy occurrence of trajectory conflicts in the eVTOL waiting path planning, thereby achieving the improvement of dynamic adaptability, geometric coordination and flight safety of path generation.

[0005] The horizontal reference path calculation method for the eVTOL waiting mode provided by the present invention includes: Collect the current eVTOL position, track angle, ground speed, and holding mode type, including hold (HF), hold (HM), and hold (HA). Determine the holding fix point based on the collected current eVTOL information, and define the straight line from the current eVTOL flying toward the holding fix point as the entry track. An auxiliary dividing line is created based on the incoming edge, pointing toward the waiting fix point, dividing the plane where the waiting fix point is located into four quadrants. The waiting entry path type is determined based on the quadrant in which the entry track is located. When the entry track is in the fourth or third quadrant, it is a direct entry type; when it is in the second quadrant, it is a modified angle entry type; when it is in the first quadrant, it is a parallel entry type. When the entry track flies toward the fix point along the outgoing edge, the modified angle entry type is forced to be selected. According to the determined waiting entry path type, the corresponding path node generation rule is called to select nodes E1 to E7 and connect them with the inbound arc, outbound arc, inbound edge, and outbound edge to form the entry segment. Then, starting from the waiting anchor point, the execution segment is formed by connecting along the waiting anchor point, outbound arc, outbound edge, inbound arc, inbound edge, and then to the waiting anchor point. When the end condition is met, the exit segment is constructed. Check the translation distance of the outbound arc relative to the original position in the entry segment. There is a maximum distance limit for the outer translation of the outbound arc, and the inner translation of the outbound arc must not cause geometric interference with the entry arc. If the outer translation distance exceeds the maximum distance limit, or the inner translation interferes with the entry arc, adjust the translation distance, arc radius or waiting position until the maximum distance limit or the requirement of not interfering with the entry arc is met, and finally form a complete eVTOL horizontal reference path.

[0006] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for calculating a horizontal reference path for an eVTOL waiting mode. The method collects the current position, track angle, ground speed and waiting mode type of the eVTOL, wherein the waiting mode types include positioning point waiting HF, manual command waiting HM and altitude layer waiting HA. The waiting positioning point is determined according to the collected current eVTOL information, and a straight line from the current eVTOL flying to the waiting positioning point is defined as an entry track. An auxiliary dividing line is created based on the inbound edge, and the direction of the auxiliary dividing line points to the waiting positioning point. The plane where the waiting positioning point is located is divided into four areas. The waiting entry path type is determined according to the area where the entry track is located, wherein when the entry track is located in the fourth or third area, it is a direct entry type, when it is located in the second area, it is a correction angle entry type, and when it is located in the first area, it is a parallel entry type. When the entry track flies to the positioning point along the outbound edge direction, the correction angle entry type is forcibly selected. The corresponding path node generation rule is called according to the determined waiting entry path type, and nodes E1 to E7 are selected. An entry segment is constructed by connecting with the entry arc, the exit arc, the entry edge, and the exit edge. Then, starting from the waiting positioning point, the execution segment is formed by sequentially connecting along the waiting positioning point, the exit arc, the exit edge, the entry arc, the entry edge, and the waiting positioning point. When the end condition is met, an exit segment is constructed. The translation distance of the exit arc relative to the original position in the entry segment is checked. There is a maximum distance limit for the outer translation of the exit arc, and the inner translation of the exit arc shall not cause geometric interference with the entry arc. If the outer translation distance exceeds the maximum distance limit, or the inner translation interferes with the entry arc, the translation distance, arc radius or waiting positioning point position is adjusted until the maximum distance limit or the requirement of not interfering with the entry arc is met, and finally a complete eVTOL horizontal reference path is formed, thereby solving the technical problems of insufficient flexibility, rough entry path selection, and easy occurrence of trajectory conflicts in the existing eVTOL waiting path planning, thereby achieving the improvement of dynamic adaptability, geometric coordination and flight safety of path generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute an undue limitation of the present invention. Some specific embodiments of the present invention will be described in detail in an illustrative and non-restrictive manner with reference to the drawings. The same reference numerals in the drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 This is a flow chart of a method for calculating a horizontal reference path in an eVTOL waiting mode according to an embodiment of the present invention; Figure 2 Schematic diagram of an auxiliary dividing line dividing the plane where the waiting positioning point is located into four quadrants in an embodiment of the present invention; Figure 3 is a schematic diagram of a horizontal reference path in an embodiment of the present invention; Figure 4 This is a schematic diagram of the horizontal reference path corresponding to the outbound arc entry type in an embodiment of the present invention; Figure 5 This is a schematic diagram of the horizontal reference path corresponding to the outbound arc entry type in the HF mode in an embodiment of the present invention; Figure 6 This is a schematic diagram of the horizontal reference path corresponding to the outbound arc entry type in the HM / HA mode in an embodiment of the present invention; Figure 7 This is a schematic diagram of the horizontal reference path corresponding to the outbound arc entry type in an embodiment of the present invention; Figure 8 This is a schematic diagram of the horizontal reference path corresponding to the entry type within the departure arc in an embodiment of the present invention; Figure 9 This is a schematic diagram of the horizontal reference path corresponding to the entry type within the departure arc in the HF mode in an embodiment of the present invention; Figure 10 2 is another schematic diagram of the horizontal reference path corresponding to the entry type within the departure arc in the HF mode in an embodiment of the present invention; Figure 11 This is a schematic diagram of the horizontal reference path corresponding to the entry type within the outbound arc in the HM / HA mode in an embodiment of the present invention; Figure 12 This is a schematic diagram of a horizontal reference path corresponding to the SC entry type in an embodiment of the present invention; Figure 13 This is a schematic diagram of a horizontal reference path corresponding to the SC entry type in the HF mode in an embodiment of the present invention; Figure 14 is another schematic diagram of the horizontal reference path corresponding to the SC entry type in the HF mode in an embodiment of the present invention; Figure 15 This is a schematic diagram of a horizontal reference path corresponding to the SC entry type in the HM / HA mode in an embodiment of the present invention; Figure 16 is a schematic diagram of a horizontal reference path corresponding to the CSC entry type in an embodiment of the present invention; Figure 17 This is a schematic diagram of a horizontal reference path corresponding to the CSC entry type in the HF mode in an embodiment of the present invention; Figure 18 is another schematic diagram of the horizontal reference path corresponding to the CSC entry type in the HF mode in an embodiment of the present invention; Figure 19 This is a schematic diagram of a horizontal reference path corresponding to the CSC entry type in the HM / HA mode in an embodiment of the present invention; Figure 20 This is a schematic diagram of a horizontal reference path corresponding to the parallel entry type in an embodiment of the present invention; Figure 21 This is a schematic diagram of a horizontal reference path corresponding to the parallel entry type in the HF mode in an embodiment of the present invention; Figure 22 is another schematic diagram of the horizontal reference path corresponding to the parallel entry type in the HF mode in an embodiment of the present invention; Figure 23 is another schematic diagram of the horizontal reference path corresponding to the parallel entry type in the HM / HA mode in an embodiment of the present invention; Figure 24 is a schematic diagram of a horizontal reference path corresponding to an exit segment in an embodiment of the present invention; Figure 25 This is a schematic diagram of the horizontal reference path corresponding to the departure arc in an embodiment of the present invention; Figure 26 is a schematic diagram of a horizontal reference path corresponding to an outbound leg in an embodiment of the present invention; Figure 27 is another schematic diagram of the horizontal reference path corresponding to the outbound leg in an embodiment of the present invention; Figure 28 is a schematic diagram of a horizontal reference path corresponding to an entry arc in an embodiment of the present invention; Figure 29 is a schematic diagram of a horizontal reference path corresponding to an incoming leg in an embodiment of the present invention; Figure 30 2 is another schematic diagram of the horizontal reference path corresponding to the incoming edge in an embodiment of the present invention.

[0008] Description of the accompanying drawings: Figure 3-30 middle, Indicates the departure arc, with O1 as the center; Indicates the entry arc, with the center at O2; Represents an auxiliary arc. The center of the circle from left to right is Oi, where i is a natural number greater than or equal to 3. The black solid line is the executed waiting path, the green solid line is the entry track, the red solid line (transparent) is the entry segment path and the exit segment path, and the blue dashed line is the auxiliary line and arc. Indicates the length of the incoming leg, represents the diameter of the flight arc, and R represents the radius of the flight arc. DETAILED DESCRIPTION

[0009] In order to enable those skilled in the art to better understand the present invention, the technical solution in this embodiment will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiment is only a part of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.

[0010] See also Figure 1-Figure 30 This embodiment provides a method for calculating a horizontal reference path in an eVTOL waiting mode, comprising the following steps: S101, collecting the current eVTOL position, track angle, ground speed, and holding mode type, where the holding mode types include hold (HF), hold (HM), and hold (HA), determining a holding fix point based on the collected current eVTOL information, and defining a straight line from the current eVTOL flying toward the holding fix point as an entry track; S102: Creating an auxiliary dividing line based on the incoming leg, with the auxiliary dividing line pointing toward the waiting fix point, and dividing the plane where the waiting fix point is located into four quadrants; determining the waiting entry path type based on the quadrant in which the incoming track is located, wherein the incoming track is a direct entry type when it is in the fourth or third quadrant, a modified angle entry type when it is in the second quadrant, and a parallel entry type when it is in the first quadrant; and when the incoming track flies toward the fix point along the outgoing leg, the modified angle entry type is forcibly selected; S103: Based on the determined waiting entry path type, the corresponding path node generation rule is called to select nodes E1 to E7 and connect them with the inbound arc, outbound arc, inbound edge, and outbound edge to form an entry segment. Starting from the waiting anchor point, the execution segment is formed by sequentially connecting the waiting anchor point, the outbound arc, the outbound edge, the inbound arc, the inbound edge, and the waiting anchor point. When the termination condition is met, an exit segment is constructed. S104. Check the translation distance of the outbound arc relative to the original position in the entry segment. There is a maximum distance limit for the outer translation of the outbound arc, and the inner translation of the outbound arc must not geometrically interfere with the entry arc. If the outer translation distance exceeds the maximum distance limit, or the inner translation interferes with the entry arc, adjust the translation distance, arc radius, or waiting position until the maximum distance limit or the requirement of not interfering with the entry arc is met, ultimately forming a complete eVTOL horizontal reference path.

[0011] It should be noted that the method provided in this embodiment addresses technical issues in existing eVTOL holding path planning, such as insufficient flexibility, rough entry path selection, and prone to trajectory conflicts. This method further enhances dynamic adaptability, geometric coordination, and flight safety in path generation. The method collects the current eVTOL position, track angle, ground speed, and holding mode type (including hold at a fix (HF), hold at hand (HM), and hold at altitude (HA)). Based on this collected current eVTOL information, a holding fix is determined, and the straight line from the current eVTOL to the holding fix is defined as the entry track. This enables path planning to perceive and respond to the eVTOL's flight status in real time. Instead of relying on fixed trajectory templates, the method dynamically determines the holding fix and constructs the corresponding entry track, providing a foundation for subsequent path type selection and trajectory segment layout. This effectively addresses the existing problem of lack of real-time personalized path adaptation and improves the dynamic and airworthiness of path generation. In addition, an auxiliary dividing line is created based on the inbound edge. The direction of the auxiliary dividing line points to the waiting positioning point, dividing the plane where the waiting positioning point is located into four areas. The waiting entry path type is determined according to the area where the entry track is located. When the entry track is in the fourth or third area, it is a direct entry type. When it is in the second area, it is a corrected angle entry type. When it is in the first area, it is a parallel entry type. When the entry track flies toward the positioning point along the outbound edge, the corrected angle entry type is forced to be selected, thereby realizing intelligent determination of the path type based on spatial orientation and entry angle. By linking regional division with path type, the problems of rough path classification and highly subjective entry method selection in the existing technology are solved, ensuring that the selected path type is highly matched with the current posture and direction of the eVTOL, effectively improving the smoothness and execution rationality of the entry segment. In addition, according to the determined waiting entry path type, the corresponding path node generation rule is called, and nodes E1 to E7 are selected to connect with the inbound arc, outbound arc, inbound edge, and outbound edge to construct the entry segment. Then, starting from the waiting positioning point, the execution segment is formed along the waiting positioning point, outbound arc, outbound edge, inbound arc, inbound edge, and then to the waiting positioning point. When the end condition is met, the exit segment is constructed, realizing the modular design and continuity guarantee of the waiting path structure, ensuring the clear connection logic and continuous geometric shape between path segments, solving the problem of discontinuity or trajectory conflict between path segments, and significantly improving the spatial coordination and control stability of trajectory planning.In addition, the translation distance of the outbound arc relative to the original position in the entry segment is checked. There is a maximum distance limit for the outer translation of the outbound arc, and the inner translation of the outbound arc must not cause geometric interference with the entry arc. If the outer translation distance exceeds the maximum distance limit, or the inner translation interferes with the entry arc, the translation distance, arc radius or waiting position is adjusted until the maximum distance limit or the requirement of not interfering with the entry arc is met, thereby realizing geometric interference detection and automatic parameter adjustment between path segments, ensuring that the path structure complies with the spatial layout specifications, effectively solving the problems of trajectory conflicts and unavailable flight paths, and improving the engineering feasibility and operational safety of the path plan.

[0012] Preferably, the direct entry type is subdivided into the outbound arc entry type, the outbound arc entry type and the outbound arc entry type according to the relative position of the outbound arc and the entry track. It should be noted that the direct entry type is subdivided into the outbound arc entry type, the outbound arc entry type and the outbound arc entry type according to the relative position of the outbound arc and the entry track, which solves the technical problem that the existing path classification is too rough and cannot accurately match the aircraft entry angle and the waiting structure, thereby providing a more recognizable path selection basis, making the path construction more consistent with the actual spatial position relationship, realizing the precision of path type determination and the systematicness of operation logic, providing a flexible adaptation basis for flight path matching under different situations, and enhancing the practicality and safety of path planning.

[0013] Preferably, the specific path of the entry segment of the entry type outside the outbound arc includes: the path from the entry track to node E1, wherein E1 is the tangent point of the entry track and the arc after translation outside the outbound arc; the path from node E1 to node E3, wherein E3 is the tangent point of the arc after translation outside the outbound arc and the outbound edge; the path from node E3 to node E4, wherein E4 is the node connecting the arc after translation outside the outbound arc and the starting end of the execution segment; node E4 is connected to the starting position of the execution segment. It should be noted that the specific entry path of the entry type outside the outbound arc includes: the path from the entry track to node E1, where E1 is the tangent point of the entry track and the arc after the outbound arc is translated outside; the path from node E1 to node E3, where E3 is the tangent point of the arc after the outbound arc is translated outside and the outbound edge; the path from node E3 to node E4, where E4 is the node connecting the arc after the outbound arc is translated outside and the starting end of the execution segment; node E4 is connected to the starting position of the execution segment, which solves the problems of unclear path connection order and disordered node layout in the scenario of entry outside the outbound arc. By proposing a path logic of cutting in along the entry direction, smoothly transitioning to the outbound edge and then connecting to the execution segment, the feasibility of the external entry path and the continuity of the trajectory are ensured. At the same time, the clarity and reconfigurability of the path construction are enhanced through the node series structure, and the systematization and boundary controllability of trajectory calculation are realized.

[0014] Preferably, the specific path of the entry segment of the outbound arc entry type includes: the entry track is directly connected to the tangent point B on the outbound arc and the entry track, without setting other path node transitions, wherein the tangent point B is the position where the entry track is directly tangent to the outbound arc. It should be noted that the specific path of the entry segment of the outbound arc entry type includes: the entry track is directly connected to the tangent point B on the outbound arc and the entry track, which solves the problem of unnecessary addition of transition nodes in the path and resulting in complex control. This path type is suitable for scenarios where the aircraft directly enters the outbound arc in a tangent direction, avoids path detours and node redundancy, achieves the shortest connection path, and improves control response speed and execution efficiency.

[0015] Preferably, the specific path of the entry segment of the entry type within the outbound arc includes: the path of the entry track connected to the node E1; the path of the node E1 connected to the node E3; the path of the node E3 connected to the node E4; the node E4 connected to the starting position of the execution segment; when the arc of the inner translation of the outbound arc geometrically interferes with the inbound arc, the positions of the nodes E1, E3, and E4 are determined by gradually reducing the distance of the inner translation until the interference is eliminated. It should be noted that when the arc of the inner translation of the outbound arc geometrically interferes with the inbound arc, the positions of the nodes E1, E3, and E4 are determined by gradually reducing the distance of the inner translation until the interference is eliminated, thereby solving the technical problem that the spatial overlapping interference problem is easily ignored in the path calculation and affects the flight safety. In this embodiment, the trajectory conflict is eliminated by dynamically adjusting the translation distance to ensure that there is a minimum safety distance between the outbound arc and the inbound arc, achieve geometric compatibility and dynamic adjustability between the path segments, and improve the robustness of the overall path and the stability of the flight process.

[0016] Preferably, the correction angle entry type is divided into SC entry type and CSC entry type according to the angle between the entry track and the outbound leg. The SC entry type is composed of the entry track to node E1 and then to node E3. The CSC entry type path is composed of the entry track to node E1, and then through node E2, node E4 to node E5. The CSC entry type reduces the interception distance by increasing the angle of intercepting the outbound leg to 45°. It should be noted that the correction angle entry type is divided into SC entry type and CSC entry type according to the angle between the entry track and the outbound leg. The SC entry type is composed of the entry track to node E1 and then to node E3. The CSC entry type path is composed of the entry track to node E1, and then through node E2, node E4 to node E5. The CSC entry type reduces the interception distance by increasing the angle of intercepting the outbound leg to 45°, which solves the problem that the entry track deviation angle is too large, resulting in a long distance connecting the outbound leg, which is not conducive to the compact configuration of the path. In this embodiment, through the classification structure and angle restriction, the function of capturing control points by the shortest path is realized under the condition of limited space resources, effectively taking into account the simplicity of the path and the smoothness of the entry angle, and realizing the optimization of the angle constraint during path connection and the enhancement of the track controllability.

[0017] Preferably, the entry segment path of the parallel entry type is from the entry track to node E1, connected to the entry edge via node E2, and then connected to node E4 via node E3, and node E4 is connected to node E6 via node E5 to enter the execution segment; the parallel entry type ensures that the interception angle of the entry path is within the specified range, and there is no geometric interference between all arcs. It should be noted that the entry segment path of the parallel entry type is from the entry track to node E1, connected to the entry edge via node E2, and then connected to node E4 via node E3, and node E4 is connected to node E6 via node E5 to enter the execution segment; the parallel entry type ensures that the interception angle of the entry path is within the specified range, and there is no geometric interference between all arcs, which solves the problem that the parallel entry path is prone to long-distance parallel flight and overlapping interference of curves. In this embodiment, by strictly limiting the interception angle and controlling the geometric relationship of the trajectory segments, the overall geometric rationality of the path and the safety of the control operation are improved, which is particularly suitable for scenarios where the aircraft approaches the waiting area from a long distance and in a parallel direction.

[0018] Preferably, when the waiting mode type is HM, if there is insufficient space when the current position enters the waiting mode, the waiting positioning point will be moved a preset distance ahead of the entry track to expand the entry path space, and then the entry path will be re-determined. It should be noted that when the waiting mode type is HM, if there is insufficient space when the current position enters the waiting mode, the waiting positioning point will be moved a preset distance ahead of the entry track to solve the problem of being unable to construct an entry path due to limited space in dynamic scenes. In this embodiment, through the intelligent adjustment of the waiting point position, the risk of path planning failure due to space constraints in the waiting area is avoided, the system's response capability in high-density airspace is improved, and the path planning scene adaptability and space utilization are significantly enhanced.

[0019] Preferably, the exit segment is applicable to the waiting modes HM and HA. The exit path must be separated from the execution segment at the approaching side. The eVTOL separation order is determined when the execution segment is separated. The specific exit path is determined according to the location at the time of separation to connect to the subsequent flight phase. It should be noted that the exit segment is applicable to the waiting modes HM and HA. The exit path must be separated from the execution segment at the approaching side. The eVTOL separation order is determined when the execution segment is separated. The specific exit path is determined according to the location at the time of separation to connect to the subsequent flight phase. This solves the problem of the traditional waiting path lacking an exit strategy at the end link, ensures that the eVTOL can quickly and orderly separate from the trajectory and enter the next mission flight path after completing the waiting mission, effectively improving the integrity of path planning and the safety of mission switching. It is particularly suitable for multi-machine scheduling or temporary scheduling change scenarios.

[0020] Preferably, the exit segment path is determined according to the different positions of the eVTOL when it disengages from the execution segment: when the eVTOL is located at the outbound arc, it flies to the inbound side and then disengages; when the eVTOL is located at the front section of the outbound side, it continues to fly along the outbound side; when the eVTOL is located at the rear section of the outbound side, a turn is created at the current position to disengage; when the eVTOL is located at the inbound arc, it flies to the inbound side and then disengages; when the eVTOL is located at the front section of the inbound side, it continues to fly along the inbound side; when the eVTOL is located at the rear section of the inbound side, a turn is created at the current position to disengage. It should be noted that the determination of the exit path is based on the different positions of the eVTOL when it leaves the execution segment: when the eVTOL is on the outbound arc, it flies to the inbound side and then leaves; when the eVTOL is at the front of the outbound side, it continues to fly along the outbound side; when the eVTOL is at the back of the outbound side, a turn is created at the current position to leave; when the eVTOL is on the inbound arc, it flies to the inbound side and then leaves; when the eVTOL is at the front of the inbound side, it continues to fly along the inbound side; when the eVTOL is at the back of the inbound side, a turn is created at the current position to leave, solving the problem that the exit path is fixed and rigid and cannot be adapted to local conditions. In this embodiment, different trajectory exit strategies are matched to the different actual detachment points of the eVTOL to achieve accurate and rapid path connection and task transfer, improve the flexibility of the path final state control, ensure the safe closed loop of the flight mission, and high path logic integrity. It is suitable for high-precision path control systems for autonomous flight scheduling.

[0021] In some embodiments, the present invention provides entry, execution, and exit paths for wait mode. Figure 2 In the entry phase, when the aircraft is flying along a straight line toward the anchor point, the track along the straight line is the entry track. Taking clockwise rotation as an example, rotate the entry edge 70° counterclockwise to create an auxiliary dividing line. The dividing line points toward the anchor point, dividing the plane into four parts. Based on the area to which the entry track belongs, the type of waiting entry path is determined. The relationship is as follows: 1) : Direct access (Direct); 2) : Correction angle entry (Teardrop); 3) : Parallel entry (Parallel).

[0022] See also Figure 3 , Indicates the angle from the dividing line to the entry track in a clockwise direction. In special cases, when the entry track is flying toward the fix point along the outbound side, a holding entry path with a correction angle should be used. When the holding mode is HM, when entering the holding mode at the current position, if necessary, the fix point can be moved a short distance ahead of the entry track to create enough space for the entry path. Based on the position of the path relative to the outbound arc, the direct entry path should be subdivided into the following three categories: 1) : Outbound arc entry type; 2) : Outbound arc entry type; 3) : Entry type within the departure arc; see Figure 4-Figure 6 When the direct entry path is the entry outside the departure arc, E1 is and the point of tangency of the entry track. E2 is The point of tangency with the inbound edge. E3 is The point of tangency with the outbound edge. Is the outer translation relative to the departure arc toward the holding pattern , the maximum translation distance is: ; There is no interference with the entry arc. Figure 5 , when the holding pattern type is HF, the entry path is: "Enter track → E1 → E3 → E4 → E5 → B". Figure 6 , when the holding mode type is HM / HA, the entry path is: "Enter track → E1 → E3 → E4 → B". and is the same circle. Figure 7 , when the direct entry path is the outbound arc entry type, the entry path is: "Enter track → B". Figure 8 When the direct entry path is within the departure arc, the entry path is: "Enter track → B". E1 is and the tangent point of the incoming track. E2 is the intersection of the incoming track and the outgoing track. E3 is The point of tangency with the outbound edge. Is the inboard translation relative to the outbound arc toward the holding pattern , possibly with Interference occurs. Figure 9 and Figure 10 , when the waiting mode type is HF, when , exist On the left, the entry path is: "Enter track → E1 → E3 → E4 → E5 → B". Figure 10 ,when , exist On the right, the entry path is "Enter Track → E1 → E3 → E4 → B". Figure 11 , when the holding mode type is HM / HA, the entry path is: "Enter track → E1 → E3 → E4 → B".

[0023] In special cases where the correction angle is used for entry, the correction angle entry path should be subdivided into the following two categories based on the planned starting track angle: 1) :SC entry type; 2) : CSC entry type. See Figure 12 , when the modified angle entry path is SC entry type, E1 is and the tangent point of the incoming track. E2 is the intersection of the incoming track and the outgoing track. E3 is The point of tangency with the outbound edge. Is the inboard translation relative to the outbound arc toward the holding pattern , possibly with Interference occurs. The aircraft intercepts the straight line of the outbound edge along the "straight line segment-circular arc segment" and intercepts the angle of the outbound edge. See also Figure 13 , when the waiting mode type is HF, when , exist On the left, the entry path is: "Enter track → E1 → E3 → E4 → E5 → B". Figure 14 ,when , exist On the right, the entry path is: "Enter track → E1 → E3 → E4 → B". Figure 15 , when the holding mode type is HM / HA, the entry path is: "Enter track → E1 → E3 → E4 → B". Figure 16 When the corrected angle entry path is CSC entry type, E1 is the tangent point of C_3 and the entry track. E2 is and The tangent point of the track. E3 is The intersection of the track and the outbound edge. E4 is and The tangent point of the track. E5 is The point of tangency with the outbound edge. Is the outer translation relative to the departure arc toward the holding pattern . It is the inward translation relative to the departure arc toward the holding pattern , possibly with Interference occurs. The aircraft intercepts the straight line of the outbound edge along the arc segment-straight segment-arc segment. Increase the angle of intercepting the outbound leg to 45°, reducing the distance required to intercept the outbound leg. Figure 17, when the waiting mode type is HF, when hour, exist On the left, enter the path: "Enter track → E1 → E2 → E4 → E5 → E6 → E7 → B". See Figure 18 ,when hour, exist On the right, enter the path: "Enter track → E1 → E2 → E4 → E5 → E6 → B". Figure 19 , when the holding mode type is HM / HA, the entry path is: "Enter track → E1 → E2 → E4 → E5 → E6 → B".

[0024] In case of parallel entry, see Figure 20 , E1 is and the point of tangency of the entry track. E2 is The point of tangency with the inbound edge. E3 is and the intersection of the inbound leg. E4 is The tangent point of the outbound edge. E5 is and The tangent point of the track. E6 is and The tangent point of the track. Is the inboard translation relative to the outbound arc toward the holding pattern , possibly with Interference occurs. It is the inward translation relative to the departure arc toward the holding pattern , possibly with Interference occurs. ,Right now exist The aircraft follows the path of "circular segment-straight segment-circular segment" to intercept the angle From interception to Therefore, with The following relationship should be satisfied: ; ; .

[0025] See also Figure 21 , when the waiting mode type is HF, when hour, exist On the left, the intercept angle is less than , the entry path is: "Enter track → E1 → E2 → E3 → E4 → E5 → E6 → B". Figure 22 ,when hour, exist On the right, enter the path: "Enter track → E1 → E2 → E3 → E4 → E5 → E6 → B". Figure 23 When the waiting mode type is HM / HA, the entry path is: “Enter track → E1 → E2 → E3 → E4 → E5 → E6 → B”.

[0026] The execution phase (racetrack) begins at the fix point and traverses the path from the fix point to the outbound arc, outbound edge, inbound arc, inbound edge, and back to the fix point. This completes the execution phase (racetrack). The exit phase applies to both HM and HA. The exit and entry phases of HF are integrated. The exit phase should adhere to the following principles: 1) racetrack must be disengaged on the inbound edge; 2) disengagement must be sequenced; and 3) the transition path after disengagement should refer to the transition procedure.

[0027] See also Figure 24 To ensure the space for the subsequent transition path, sufficient lead time should be reserved when entering the port and entering the side of the channel. According to the position when the end condition is met, the exit path has the following forms: 1) outbound arc; 2) outbound edge; 3) inbound arc; 4) inbound edge. Figure 25 ; See the departure side Figure 26 and Figure 27 , Figure 26 Shows the outbound side forward, Figure 27 Shows the outbound side Then, create at the end position , turn immediately. Figure 28 . See the entry side Figure 29 and Figure 30 , Figure 29 Shows the inbound edge at forward, Figure 30 Shows the inbound edge at Then, create at the end position , turn immediately.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calculating a horizontal reference path in an eVTOL waiting mode, characterized in that: include: Collect the current eVTOL position, track angle, ground speed, and holding mode type, including hold (HF), hold (HM), and hold (HA). Determine the holding fix point based on the collected current eVTOL information, and define the straight line from the current eVTOL flying toward the holding fix point as the entry track. An auxiliary dividing line is created based on the incoming edge, pointing toward the waiting fix point, dividing the plane where the waiting fix point is located into four areas. The waiting entry path type is determined based on the area where the incoming track is located. When the incoming track is in the fourth or third area, it is a direct entry type; when it is in the second area, it is a modified angle entry type; when it is in the first area, it is a parallel entry type. When the incoming track flies toward the fix point along the outgoing edge, the modified angle entry type is forced to be selected. According to the determined waiting entry path type, the corresponding path node generation rule is called to select nodes E1 to E7 and connect them with the inbound arc, outbound arc, inbound edge, and outbound edge to form the entry segment. Then, starting from the waiting anchor point, the execution segment is formed by connecting along the waiting anchor point, outbound arc, outbound edge, inbound arc, inbound edge, and then to the waiting anchor point. When the end condition is met, the exit segment is constructed. Check the translation distance of the outbound arc relative to the original position in the entry segment. There is a maximum distance limit for the outer translation of the outbound arc, and the inner translation of the outbound arc must not cause geometric interference with the entry arc. If the outer translation distance exceeds the maximum distance limit, or the inner translation interferes with the entry arc, adjust the translation distance, arc radius or waiting position until the maximum distance limit or the requirement of not interfering with the entry arc is met, and finally form a complete eVTOL horizontal reference path.

2. The horizontal reference path calculation method for the eVTOL waiting mode according to claim 1, characterized in that: The direct entry type is subdivided into entry outside the departure arc type, entry outside the departure arc type and entry inside the departure arc type according to the relative position of the departure arc and the entry track.

3. The horizontal reference path calculation method for the eVTOL waiting mode according to claim 2, characterized in that: The specific path of the entry segment of the entry type outside the outbound arc includes: the path from the entry track to node E1, where E1 is the tangent point of the entry track and the arc after the outbound arc is translated outside; the path from node E1 to node E3, where E3 is the tangent point of the arc after the outbound arc is translated outside the outbound arc and the outbound edge; the path from node E3 to node E4, where E4 is the node connecting the arc after the outbound arc is translated outside the outbound arc and the starting end of the execution segment; node E4 is connected to the starting position of the execution segment.

4. The horizontal reference path calculation method for the eVTOL waiting mode according to claim 2, characterized in that: The specific path of the entry segment of the outbound arc entry type includes: the entry track is directly connected to the tangent point B on the outbound arc and the entry track, without setting other path node transitions, where the tangent point B is the position where the entry track is directly tangent to the outbound arc.

5. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 3, wherein: The specific path of the entry segment of the entry type within the outbound arc includes: the path of the entry track connected to node E1; the path of node E1 connected to node E3; the path of node E3 connected to node E4; node E4 is connected to the starting position of the execution segment; when the arc of the inner translation of the outbound arc geometrically interferes with the inbound arc, the positions of nodes E1, E3, and E4 are determined by gradually reducing the distance of the inner translation until the interference is eliminated.

6. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 1, wherein: The corrected angle approach is divided into SC approach and CSC approach based on the angle between the approach track and the outbound leg. The SC approach consists of the approach track to node E1 and then to node E3. The CSC approach path consists of the approach track to node E1, then to node E2, node E4 and finally to node E5. The CSC approach reduces the interception distance by increasing the interception angle of the outbound leg to 45°.

7. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 1, wherein: The entry path of the parallel entry type is from the entry track to node E1, connected to the entry edge through node E2, then connected to node E4 through node E3, and node E4 is connected to node E6 through node E5 to enter the execution segment; the parallel entry type ensures that the interception angle of the entry path is within the specified range and there is no geometric interference between all arcs.

8. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 1, wherein: When the holding mode type is HM, if there is insufficient space when the current position enters the holding mode, the holding position will be moved a preset distance ahead of the entry track to expand the entry path space, and then the entry path will be re-determined.

9. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 1, wherein: The exit segment is applicable to the holding modes HM and HA. The exit path must be separated from the execution segment on the approaching side. The eVTOL separation order is determined when separating from the execution segment, and the specific exit path is determined according to the location at the time of separation to connect the subsequent flight phase.

10. The method for calculating the horizontal reference path in the eVTOL waiting mode according to claim 9, characterized in that: The exit segment path is determined according to the different positions of the eVTOL when it leaves the execution segment: when the eVTOL is on the outbound arc, it flies to the inbound side and then leaves; when the eVTOL is at the front of the outbound side, it continues to fly along the outbound side; when the eVTOL is at the back of the outbound side, a turn is created at the current position to leave; when the eVTOL is on the inbound arc, it flies to the inbound side and then leaves; when the eVTOL is at the front of the inbound side, it continues to fly along the inbound side; when the eVTOL is at the back of the inbound side, a turn is created at the current position to leave.

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