A fixed-wing UAV air glide return strategy and online route planning method

Abstract

The present invention relates to the field of UAV flight test technology, and in particular to a fixed-wing UAV air glide return strategy and route online planning method. The method comprises the following steps: constructing a route online planning coordinate system and a coordinate transformation matrix group within the system, and obtaining the coordinates of the endpoint A, endpoint B, and parking point S of the UAV runway in the system; calculating the glide return point F n Coordinates of landing heading adjustment circle center O fi The coordinates of the parking point and the heading adjustment circle center O sj The coordinates of the runway are then divided into zones around the runway, and a return glide strategy is determined based on the coordinates of each point. Based on this strategy, a return glide route is generated. This technical solution ensures that an effective return glide strategy and return route are generated immediately after the drone is parked in mid-air. The drone then returns along the generated route, mitigating the risks of mid-air parking test flights and preventing drone asset losses.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) flight test technology, and in particular to an air-gliding return strategy and an online route planning method for a fixed-wing UAV. Background Art

[0002] During maneuvering, drones have relatively large angles of attack and sideslip, making them prone to mid-flight engine stalls due to air intake problems. Once a mid-flight stall occurs, the drone loses all thrust, unable to maintain high speeds and speeds. Energy continues to deplete, and when depleted, the drone crashes.

[0003] A glide return refers to the entire process of finding a suitable airport or open area within a limited timeframe after a drone loses thrust, developing a glide strategy and planning a glide route, and then gliding unpowered along the glide route until touchdown. Glide return is an emergency measure to ensure drone safety in the event of a stall. Improperly designed glide return strategies and routes can lead to a failed return, potentially resulting in a serious accident. For manned aircraft, glide return decisions primarily rely on the pilot's calm on-the-spot response and excellent flying skills. However, for drones, lacking pilot control and operational expertise, glide strategy development and route planning are even more crucial. The flight process after a drone stall is a continuous process of energy consumption. Therefore, a glide return strategy and route must be quickly implemented after a stall. These strategies and routes should adhere to the principles of optimal energy utilization and minimal energy loss, ensuring the drone's safe return to the air within its limited capacity without unnecessary energy loss. Since the parking status of a drone cannot be predicted in advance, an online glide return strategy and glide return route planning must be performed based on the drone's status when it is parked in the air. Summary of the Invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned existing technologies and propose a fixed-wing UAV air glide return strategy and route online planning method to ensure that an effective air glide return strategy and return route are generated in a timely manner after the UAV is parked in the air. The UAV air glides back along the generated route, eliminating the risk of UAV air parking test flight and avoiding UAV asset loss.

[0005] The technical solutions adopted to achieve the above objectives are as follows:

[0006] A fixed-wing UAV glide return strategy and route online planning method includes the following steps:

[0007] S1, with the midpoint of the drone runway as the center, build a coordinate system for online route planning;

[0008] S2, obtain the coordinates of the endpoint A, endpoint B and parking point S of the drone runway in the online route planning coordinate system;

[0009] S3, establishing a coordinate transformation matrix group within the online route planning coordinate system;

[0010] S4, in the online route planning coordinate system, calculate the air gliding point F based on endpoints A and B combined with the coordinate transformation matrix n coordinates, and use air gliding to slide point F n The coordinates of the landing course adjustment circle are calculated as O fi Coordinates of the landing course adjustment circle; where n represents the position of the glide path, n = 1, 2; i represents the position of the landing course adjustment circle, i = 1, 2, 3, 4;

[0011] S5, in the route online planning coordinate system, based on the coordinates of the parking point S and the coordinate conversion matrix, obtain the center O of the parking point heading adjustment circle sj Coordinates of; where j represents the position of the heading adjustment circle of the parking point, j = 1, 2;

[0012] S6, divide the area around the runway, and determine the return strategy based on the state of the UAV when it is parked and the runway area where the parking point S is located, including determining the gliding point F n , landing course adjustment circle center O fi and the center of the parking point heading adjustment circle O sj The position of the landing course adjustment circle and the circling direction of the parking point course adjustment circle;

[0013] S7, based on the air sliding return strategy, for the circle center O sj and the center O fi The parking point heading adjustment circle and the landing heading adjustment circle at the position are used to establish the common tangent of the two circles according to the circling directions of the landing heading adjustment circle and the parking point heading adjustment circle. And obtain the coordinates of the tangent point P1 on the parking point heading adjustment circle and the tangent point P2 on the landing heading adjustment circle;

[0014] S8, based on the air sliding return strategy, connect the parking point S, the tangent point P1, the tangent point P2 and the air sliding descent point F in sequence n According to the principle that the straight line between two points is the shortest and the arc is the shortest when there is curvature, an air-gliding return route that meets the principle of minimum energy loss is generated.

[0015] Preferably, in step S1, constructing the route online planning coordinate system includes the following steps:

[0016] S11, construct the northeast celestial coordinate system O with the midpoint of the drone runway as the center xyz_enu ; Among them, the northeast celestial coordinate system Oxyz_enu of The axis points to the east, the northeast celestial coordinate system O xyz_enu of The axis points north;

[0017] S12, construct the runway coordinate system O with the midpoint of the drone runway as the center of the circle xyz_AB ; Among them, the runway coordinate system O xyz_AB of Axis points to both ends direction, The axis rotates 90° counterclockwise to point to the runway coordinate system O xyz_AB of Axis direction;

[0018] S13, construct the track coordinate system O with the midpoint of the drone runway as the center of the circle xyz_vk ; Among them, the track coordinate system O xyz_vk of Axis pointing to the track velocity vector when parking direction, The axis rotates 90° counterclockwise to point to the track coordinate system O xyz_vk of Axis direction, track velocity vector when parking Obtained by measuring the onboard inertial navigation sensor.

[0019] Preferably, in step S2, the endpoint A, the endpoint B and the parking point S are obtained by calculation in the northeastern sky coordinate system O. xyz_enu Specifically, endpoint A, endpoint B, and parking point S are collectively referred to as point Q, then:

[0020]

[0021] y Q_enu =[6367449.134-32077×cos(B Q +B0)]×(B Q -B0);

[0022] Among them, (x Q_enu ,y Q_enu ) indicates that point Q is in the northeast celestial coordinate system O xyz_enu The coordinate value of B Q Indicates the latitude of point Q; B0 indicates the latitude of the coordinate origin; L Q represents the longitude of point Q; L0 represents the longitude of the coordinate origin; a and b are both constants, a=6383487.606, b=5357.31.

[0023] Preferably, in step S3, establishing a coordinate transformation matrix group within the route online planning coordinate system includes the following steps:

[0024] S31, establish the direction vector from endpoint A to endpoint B And use the direction vector Establish runway coordinate system O xyz_AB To the Northeast Celestial Coordinate System O xyz_enu The coordinate transformation matrix L AB2enu , that is:

[0025]

[0026] Among them, θ AB2OX Represents the direction vector and The angle between the axis and the

[0027] S32, establish the Northeast Celestial Coordinate System O xyz_enu To runway coordinate system O xyz_AB The coordinate transformation matrix L enu2AB , that is:

[0028] S33, using the trajectory velocity vector when parking Establish track coordinate system O xyz_vk To runway coordinate system O xyz_AB The coordinate transformation matrix L vk2AB , that is:

[0029]

[0030] Among them, θ vk2OX Represents the trajectory velocity vector when parking Direction and The angle between the axis and the

[0031] S34, establish runway coordinate system O xyz_AB To track coordinate system O xyz_vk The coordinate transformation matrix L AB2vk , that is:

[0032] Preferably, in step S4, the sliding point F is obtained according to the air sliding. n The coordinates of the position are calculated by the following steps:

[0033] S41, obtain the coordinates of endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below are:

[0034]

[0035]

[0036] Among them, (x A_enu ,y A_enu ) and (x B_enu ,y B_enu ) represent endpoints A and B in the northeast celestial coordinate system O xyz_enu The coordinates below; (x A_AB ,y A_AB ) and (x B_AB ,y B_AB ) are respectively represented as endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below;

[0037] S42, let the air slide down point F n The distance to the nearest endpoint is L, that is, L = h * k; where h is the height of the gliding point relative to the airport runway, and k is the optimal glide ratio of the UAV;

[0038] S43, calculate the air gliding descent point F n The coordinates of , that is:

[0039] When n=1, the air sliding gliding point F1 is on the side of the endpoint A, and the distance from the air sliding gliding point F1 to the endpoint A is L. The coordinate calculation formula is: Among them, (x F1_AB ,y F1_AB ) represents the airborne glide path F1 in the runway coordinate system O xyz_AB The coordinate value of the following;

[0040] When n=2, the air gliding descent point F2 is on the side of the endpoint B, and the distance from the air gliding descent point F2 to the endpoint B is L. The coordinate calculation formula is: Among them, (x F2_AB ,y F2_AB ) represents the gliding point F2 in the runway coordinate system O xyz_AB The coordinate value below.

[0041] Preferably, in step S4, the center O of the circle is calculated based on the position of the landing heading adjustment circle. fi coordinates; let the landing heading adjustment circle center O fi In the runway coordinate system O xyz_AB The coordinates below are expressed as (x Ofi_AB ,y Ofi_AB ), the radius of the landing course adjustment circle is R, that is:

[0042] When i=1, the landing course adjustment circle is the upper tangent circle of the airborne glide point F1, and the coordinate calculation formula is:

[0043] When i=2, the landing course adjustment circle is the circle tangent to the glide path F1, and the coordinate calculation formula is:

[0044] When i=3, the landing course adjustment circle is the circle tangent to the glide path F2, and the coordinate calculation formula is:

[0045] When i=4, the landing course adjustment circle is the upper tangent circle of the airborne glide path F2, and the coordinate calculation formula is:

[0046] Preferably, in step S5, the center O of the circle is obtained according to the position of the heading adjustment circle of the parking point. sj The coordinates of , including the following steps:

[0047] S51, obtain the parking point S in the runway coordinate system O xyz_AB The coordinates (x S_AB ,y S_AB );Right now Among them, (x S_enu ,y S_enu ) indicates that the parking point S is in the northeast celestial coordinate system O xyz_enu The coordinates below;

[0048] S52, obtain the parking point S in the track coordinate system O xyz_vk The coordinates (x S_vk ,y S_vk ),Right now:

[0049] S53, calculate the center O of the heading adjustment circle at the parking point S sj In the track coordinate system O xyz_vk The coordinates (x Osj_vk ,y Osj_vk ), the radius of the parking point heading adjustment circle is r, that is:

[0050] When j=1, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the upper tangent circle at the parking point S is:

[0051] When j = 2, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the tangent circle at the parking point S is:

[0052] S54, obtaining the center O of the parking point heading adjustment circle through coordinate conversion sj In the runway coordinate system O xyz_AB The coordinates (xOsj_AB ,y Osj_AB ),Right now:

[0053] Preferably, in step S6, dividing the area around the runway includes the following steps:

[0054] S611: Draw perpendicular lines to the runway based on the air gliding points F1 and F2, respectively, to establish coordinate systems with F1 and F2 as the center. F1 and O F2 ;

[0055] S612, coordinate system based on the center of the circle and Divide the area around the runway, that is: let the coordinate system The second quadrant is area A, the third quadrant is area B, and the coordinate system The fourth quadrant is area C, the first quadrant is area D, and the coordinate system The first quadrant and coordinate system The second quadrant is the E area, so that the coordinate system The fourth quadrant and coordinate system The third quadrant is the F area.

[0056] Preferably, in step S6, the air sliding point F is determined. n Position landing heading adjustment circle center O fi The method of adjusting the circling direction based on the position and landing heading is as follows:

[0057] When the parking point S is in area A, the gliding point is F1 and the center of the landing course adjustment circle is O. f1 , circling left in landing course adjustment circle;

[0058] When the parking point S is in area B, the gliding point is F1 and the landing course adjustment circle is O f2 , adjust the landing course circle to the right;

[0059] When the parking point S is in area C, the gliding point is F2 and the landing course adjustment circle is O f3 , circling left in landing course adjustment circle;

[0060] When the parking point S is in the D area, the gliding point is F2 and the landing course adjustment circle is O f4 , adjust the landing course circle to the right;

[0061] When the parking point S is in the E zone; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f4, the landing course adjustment circle turns right; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f1 , circling left in landing course adjustment circle;

[0062] When the parking point S is in the F area; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f3 , the landing course adjustment circle turns left; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f2 , adjust the landing course and circle right.

[0063] Preferably, in step S6, the center O of the parking point heading adjustment circle is determined. sj The method of adjusting the circling direction of the circle is as follows: based on the parking point S and the gliding point F n Create vector when When the parking point heading adjustment circle is centered at O s2 , the parking point course adjustment circle circles right; when When the parking point heading adjustment circle is centered at O s1 , the parking point heading adjustment circle circles right.

[0064] Preferably, in step S7, a common tangent line is established And obtaining the coordinates of the tangent point P1 and the tangent point P2 includes the following steps:

[0065] S71, using the determined parking point heading to adjust the circle center O sj and the landing heading adjustment circle center O fi Create a direction vector

[0066] S72, with the midpoint of the drone runway as the center, construct the center coordinate system O xyz_OO ; Center coordinate system O xyz_OO of Axis direction direction, The axis rotates 90° counterclockwise to point to the center coordinate system O xyz_OO of Axis direction;

[0067] S73, establish the circle center coordinate system O xyz_OO To runway coordinate system O xyz_ABThe coordinate transformation matrix L oo2AB ,Right now:

[0068]

[0069] Among them, θ oo2OX is the direction vector and The angle between the axis and the

[0070] S74, establish runway coordinate system O xyz_AB To the center coordinate system O xyz_OO The coordinate transformation matrix L AB2oo ,Right now

[0071] S75, calculate the center O of the parking point heading adjustment circle sj and the landing heading adjustment circle center O fi In the center coordinate system O xyz_OO The coordinates (x Osj_OO ,y Osj_OO ), that is: and

[0072] S76, based on the center O sj and the center O fi In the center coordinate system O xyz_OO According to the circling direction of the parking point heading adjustment circle and the landing heading adjustment circle, the tangent point P1 and the tangent point P2 are calculated in the circle center coordinate system O xyz_OO The coordinates of the tangent point P1 and the tangent point P2 are expressed as (x P1_OO ,y P1_OO ) and (x P2_OO ,y P2_OO ) that is:

[0073] When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the right, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0074]

[0075]

[0076] When the parking point course adjustment circle is circling left and the landing course adjustment circle is circling left, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0077]

[0078]

[0079] When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the left, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0080]

[0081]

[0082] When the parking point course adjustment circle circles left and the landing course adjustment circle circles right, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0083]

[0084]

[0085] Preferably, in step S8, the air taxi return route that satisfies the principle of minimum energy loss is generated by transforming the parking point S, the tangent point P1, the tangent point P2 and the air taxi descent point F into the corresponding coordinate transformation matrix. n Convert to the Northeast Celestial Coordinate System O xyz_enu Next, in the northeast sky coordinate system O xyz_enu Next, the connection points S, P1, P2 and F are generated. n The air gliding return route.

[0086] The beneficial technical effects brought about by the present invention are:

[0087] This technical solution proposes a method for online planning of a glide return strategy and route for a fixed-wing UAV, which realizes the online planning of the UAV's glide return strategy and route standardization. It can ensure that an effective glide return strategy and return route are generated in a timely manner after the UAV is parked in the air. The UAV glides back along the generated route, effectively eliminating the risks associated with the UAV's mid-air parking test flight and further avoiding the loss of UAV assets. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 This is the basic implementation flow chart of this technical solution;

[0089] Figure 2 This is a schematic diagram of the northeast celestial coordinate system;

[0090] Figure 3 This is a schematic diagram of the runway coordinate system;

[0091] Figure 4 It is a schematic diagram of the track coordinate system;

[0092] Figure 5The diagram is a schematic diagram of the position of the glide path point in the runway coordinate system;

[0093] Figure 6 This is a schematic diagram of the position of the landing heading adjustment circle in the runway coordinate system;

[0094] Figure 7 This is a schematic diagram of the position of the parking point heading adjustment circle in the runway coordinate system;

[0095] Figure 8 This is a schematic diagram of the parking area division in the runway coordinate system;

[0096] Figure 9 This is a schematic diagram of the entry and exit points of the outer common tangent;

[0097] Figure 10 Schematic diagram of the entry and exit points of the internal tangent line;

[0098] Figure 11 It is a schematic diagram of the entry and exit points in the circle center coordinate system;

[0099] Figure 12 This is a schematic diagram of the relative positions of the runway and the parking point in the northeast celestial coordinate system;

[0100] Figure 13 Schematic diagram of the relative positions of the runway, the glide path point and the parking point in the runway coordinate system;

[0101] Figure 14 This is a schematic diagram of the landing heading adjustment circle position in the runway coordinate system;

[0102] Figure 15 The data table for planning the return taxi route in the runway coordinate system;

[0103] Figure 16 This is the data table for planning the return route of the air taxi in the northeast celestial coordinate system;

[0104] Figure 17 Schematic diagram of the air taxi return route planning in the runway coordinate system;

[0105] Figure 18 This is a schematic diagram of the air gliding return route planning in the northeast celestial coordinate system. DETAILED DESCRIPTION

[0106] In order to make the purpose, technical solutions and advantages of the invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0107] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0108] Example 1

[0109] This embodiment discloses a fixed-wing UAV air glide return strategy and route online planning method, as a basic implementation scheme of the present invention, such as Figure 1 As shown, the following steps are included:

[0110] S1: Construct an online route planning coordinate system with the midpoint of the drone runway as the center. This coordinate system includes several coordinate systems required by the aircraft control system. Different measurement or control tasks require different coordinate systems.

[0111] S2, obtain the coordinates of the endpoint A, endpoint B and parking point S of the drone runway in the route online planning coordinate system.

[0112] S3: Establishing a coordinate transformation matrix group within the online route planning coordinate system. The air taxi return route of this technical solution requires coordinate data in different coordinate systems. These coordinate data need to be unified into the same coordinate system, which requires a corresponding coordinate transformation matrix. The coordinate transformation matrix group is composed of several coordinate transformation matrices.

[0113] S4, in the online route planning coordinate system, calculate the air gliding point F based on endpoints A and B combined with the coordinate transformation matrix n coordinates, and use air gliding to slide point F n The coordinates of the landing course adjustment circle are calculated as O fi The coordinates of the landing course adjustment circle are as follows: n represents the position of the gliding point, n=1,2; i represents the position of the landing course adjustment circle, i=1,2,3,4.

[0114] S5, in the route online planning coordinate system, based on the coordinates of the parking point S and the coordinate conversion matrix, obtain the center O of the parking point heading adjustment circle sj Coordinates of; where j represents the position of the heading adjustment circle of the parking point, j = 1, 2;

[0115] S6, divide the area around the runway, and determine the return strategy based on the state of the UAV when it is parked and the runway area where the parking point S is located, including determining the gliding point F n , landing course adjustment circle center O fi and the center of the parking point heading adjustment circle O sjThe position of the landing course adjustment circle and the circling direction of the parking point course adjustment circle;

[0116] S7, based on the air sliding return strategy, for the circle center O sj and the center O fi The parking point heading adjustment circle and the landing heading adjustment circle at the position are used to establish the common tangent of the two circles according to the circling directions of the landing heading adjustment circle and the parking point heading adjustment circle. And obtain the coordinates of the tangent point P1 on the parking point heading adjustment circle and the tangent point P2 on the landing heading adjustment circle;

[0117] S8, based on the air sliding return strategy, connect the parking point S, the tangent point P1, the tangent point P2 and the air sliding descent point F in sequence n According to the principle that the straight line between two points is the shortest and the arc is the shortest when there is curvature, an air-gliding return route that meets the principle of minimum energy loss is generated.

[0118] Example 2

[0119] This embodiment discloses a fixed-wing UAV glide return strategy and route online planning method, which, as a preferred embodiment of the present invention, includes the following steps:

[0120] S1, with the midpoint of the drone runway as the center, build a route online planning coordinate system as follows:

[0121] S11, such as Figure 2 As shown, the northeast celestial coordinate system O is constructed with the midpoint of the drone runway as the center. xyz_enu ; Among them, the northeast celestial coordinate system O xyz_enu of The axis points to the east, the northeast celestial coordinate system O xyz_enu of The axis points north.

[0122] S12, such as Figure 3 As shown, the runway coordinate system O is constructed with the midpoint of the drone runway as the center. xyz_AB ; Among them, the runway coordinate system O xyz_AB of Axis points to both ends direction, The axis rotates 90° counterclockwise to point to the runway coordinate system O xyz_AB of Axis direction.

[0123] S13, such as Figure 4 As shown, the track coordinate system O is constructed with the midpoint of the drone runway as the center. xyz_vk ; Among them, the track coordinate system O xyz_vk of Axis pointing to the track velocity vector when parking direction, The axis rotates 90° counterclockwise to point to the track coordinate system O xyz_vk of Axis direction, track velocity vector when parking Obtained by measuring the onboard inertial navigation sensor.

[0124] S2, in the online route planning coordinate system, obtain the endpoint A, endpoint B and parking point S of the drone runway in the northeast sky coordinate system O xyz_enu Lower coordinates;

[0125] S3, establish the coordinate transformation matrix group within the route online planning coordinate system, as follows:

[0126] S31, establish the direction vector from endpoint A to endpoint B And use the direction vector Establish runway coordinate system O xyz_AB To the Northeast Celestial Coordinate System O xyz_enu The coordinate transformation matrix L AB2enu , that is:

[0127]

[0128] Among them, θ AB2OX Represents the direction vector and The angle between the axis and the

[0129] S32, establish the Northeast Celestial Coordinate System O xyz_enu To runway coordinate system O xyz_AB The coordinate transformation matrix L enu2AB , that is:

[0130] S33, using the trajectory velocity vector when parking Establish track coordinate system O xyz_vk To runway coordinate system O xyz_AB The coordinate transformation matrix L vk2AB , that is:

[0131]

[0132] Among them, θ vk2OX Represents the trajectory velocity vector when parking Direction and The angle between the axis and the

[0133] S34, establish runway coordinate system O xyz_AB To track coordinate system O xyz_vkThe coordinate transformation matrix L AB2vk , that is:

[0134] S4, in the online route planning coordinate system, calculate the air gliding point F based on endpoints A and B combined with the coordinate transformation matrix n coordinates, and use air gliding to slide point F n The coordinates of the landing course adjustment circle are calculated as O fi The coordinates of the landing course adjustment circle are as follows: n represents the position of the gliding point, n=1,2; i represents the position of the landing course adjustment circle, i=1,2,3,4.

[0135] S5, in the route online planning coordinate system, based on the coordinates of the parking point S and the coordinate conversion matrix, obtain the center O of the parking point heading adjustment circle sj Coordinates of the vehicle; where j represents the position of the heading adjustment circle of the parking point, j = 1, 2.

[0136] S6, divide the area around the runway, and determine the return strategy based on the state of the UAV when it is parked and the runway area where the parking point S is located, including determining the gliding point F n , landing course adjustment circle center O fi and the center of the parking point heading adjustment circle O sj The position of the landing heading adjustment circle and the circling direction of the parking point heading adjustment circle.

[0137] S7, based on the air sliding return strategy, for the circle center O sj and the center O fi The parking point heading adjustment circle and the landing heading adjustment circle at the position are used to establish the common tangent of the two circles according to the circling directions of the landing heading adjustment circle and the parking point heading adjustment circle. And obtain the coordinates of the tangent point P1 on the parking point heading adjustment circle and the tangent point P2 on the landing heading adjustment circle.

[0138] S8, based on the air sliding return strategy, connect the parking point S, the tangent point P1, the tangent point P2 and the air sliding descent point F in sequence n According to the principle that the straight line between two points is the shortest and the arc is the shortest when there is curvature, an air-gliding return route that meets the principle of minimum energy loss is generated.

[0139] Example 3

[0140] This embodiment discloses a fixed-wing UAV air glide return strategy and route online planning method. As a preferred embodiment of the present invention, based on Example 2, in step S12, the endpoint A, endpoint B and parking point S are obtained by calculation in the northeast celestial coordinate system O xyz_enu The coordinate values under are:

[0141]

[0142] y Q_enu =[6367449.134-32077×cos(B Q +B0)]×(B Q -B0);

[0143] Among them, endpoint A, endpoint B and parking point S are collectively referred to as point Q, (x Q_enu ,y Q_enu ) indicates that point Q is in the northeast celestial coordinate system O xyz_enu That is, when point Q is the endpoint A, (x A_enu ,y A_enu ) indicates that endpoint A is in the northeast celestial coordinate system O xyz_enu The coordinate value under the Q point is the endpoint B, (x B_enu ,y B_enu ) indicates that endpoint B is in the northeast celestial coordinate system O xyz_enu When point Q is the parking point S, (x S_enu ,y S_enu ) indicates that the parking point S is in the northeast celestial coordinate system O xyz_enu The coordinate value below.

[0144] B Q Indicates the latitude of point Q. Correspondingly, when point Q is endpoint A, B A is the latitude of endpoint A, which is loaded by the ground station before the drone takes off; when point Q is endpoint B, B B is the latitude of endpoint B, which is loaded by the ground station before the drone takes off; when point Q is the parking point S, B S is the latitude of the parking point S, measured by the onboard inertial navigation sensor.

[0145] L Q Indicates the longitude of point Q. Correspondingly, when point Q is endpoint A, L A is the latitude of endpoint A, which is loaded by the ground station before the drone takes off; when point Q is endpoint B, L B is the latitude of endpoint B, which is loaded by the ground station before the drone takes off; when point Q is the parking point S, L S is the latitude of the parking point S, measured by the onboard inertial navigation sensor.

[0146] B0 represents the latitude of the coordinate origin; L0 represents the longitude of the coordinate origin; a and b are both constants, a=6383487.606, b=5357.31.

[0147] Example 4

[0148] This embodiment discloses a fixed-wing UAV air gliding return strategy and route online planning method. As a preferred embodiment of the present invention, based on Example 3, step S4 is based on the air gliding gliding point F. n The coordinates of the position are calculated by the following steps:

[0149] S41, obtain the coordinates of endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below are:

[0150]

[0151]

[0152] Among them, (x A_enu ,y A_enu ) and (x B_enu ,y B_enu ) represent endpoints A and B in the northeast celestial coordinate system O xyz_enu The coordinates below; (x A_AB ,y A_AB ) and (x B_AB ,y B_AB ) are respectively represented as endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below;

[0153] S42, let the air slide down point F n The distance to the nearest endpoint is L, that is, L = h * k; where h is the height of the glide point relative to the airport runway, which is set by the ground station before the drone takes off; k is the optimal glide ratio of the drone, which is set by the ground station before the drone takes off.

[0154] S43, calculate the air gliding descent point F n The coordinates of Figure 5 As shown, there are:

[0155] When n=1, the air sliding gliding point F1 is on the side of the endpoint A, and the distance from the air sliding gliding point F1 to the endpoint A is L. The coordinate calculation formula is: Among them, (x F1_AB ,y F1_AB ) represents the airborne glide path F1 in the runway coordinate system O xyz_AB The coordinate value of the following;

[0156] When n=2, the air gliding descent point F2 is on the side of the endpoint B, and the distance from the air gliding descent point F2 to the endpoint B is L. The coordinate calculation formula is: Among them, (x F2_AB ,y F2_AB ) represents the gliding point F2 in the runway coordinate system O xyz_AB The coordinate value below.

[0157] Example 5

[0158] This embodiment discloses a fixed-wing UAV air gliding return strategy and route online planning method. As a preferred embodiment of the present invention, in step S4 of embodiment 3, the landing course adjustment circle is a guidance circle for adjusting the course of the UAV to align with the runway before the air gliding descent, passing the air gliding descent point F n And it is tangent to the extended line of the runway. Figure 6 As shown, the circle with the tangent point F1 is O f1 and O f2 The two landing course adjustment circles are: the circle with the tangent point F2 as the center is O f3 and O f4 Based on this, the technical solution is to calculate the center O of the landing course adjustment circle according to the position of the landing course adjustment circle. fi Specifically, let the center of the landing heading adjustment circle be O fi In the runway coordinate system O xyz_AB The coordinates below are expressed as (x Ofi_AB ,y Ofi_AB ), the radius of the landing course adjustment circle is R, that is:

[0159] When i=1, the landing course adjustment circle is the upper tangent circle of the airborne glide point F1, and the coordinate calculation formula is:

[0160] When i=2, the landing course adjustment circle is the circle tangent to the glide path F1, and the coordinate calculation formula is:

[0161] When i=3, the landing course adjustment circle is the circle tangent to the glide path F2, and the coordinate calculation formula is:

[0162] When i=4, the landing course adjustment circle is the upper tangent circle of the airborne glide path F2, and the coordinate calculation formula is:

[0163] Example 6

[0164] This embodiment discloses a fixed-wing UAV air glide return strategy and route online planning method. As a preferred embodiment of the present invention, in step S5 of embodiment 3, the parking point heading adjustment circle is a guidance circle that adjusts the heading to align with the common tangent direction of the landing heading adjustment circle after the UAV stops. The radius of the heading adjustment circle is r (r=R), passing through the parking point S and tangent to the track velocity vector Direction, such as Figure 7 As shown, the tangent point of the parking point S has a circle center of O s1 and O s2Based on this, the technical solution is to obtain the center O of the parking point heading adjustment circle according to the position of the parking point heading adjustment circle. sj The coordinates of , including the following steps:

[0165] S51, obtain the parking point S in the runway coordinate system O xyz_AB The coordinates (x S_AB ,y S_AB );Right now Among them, (x S_enu ,y S_enu ) indicates that the parking point S is in the northeast celestial coordinate system O xyz_enu The coordinates below;

[0166] S52, obtain the parking point S in the track coordinate system O xyz_vk The coordinates (x S_vk ,y S_vk ),Right now:

[0167] S53, calculate the center O of the heading adjustment circle at the parking point S sj In the track coordinate system O xyz_vk The coordinates (x Osj_vk ,y Osj_vk ), the radius of the parking point heading adjustment circle is r, that is:

[0168] When j=1, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the upper tangent circle at the parking point S is:

[0169] When j = 2, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the tangent circle at the parking point S is:

[0170] S54, obtaining the center O of the parking point heading adjustment circle through coordinate conversion sj In the runway coordinate system O xyz_AB The coordinates (x Osj_AB ,y Osj_AB ),Right now:

[0171] Example 7

[0172] This embodiment discloses a fixed-wing UAV air glide return strategy and route online planning method, as a preferred embodiment of the present invention, that is, in step S6 of embodiment 3, as Figure 8 As shown, the area division around the runway includes the following steps:

[0173] S611: Draw perpendicular lines to the runway based on the air gliding points F1 and F2, and establish coordinate systems with F1 and F2 as the center. and

[0174] S612, coordinate system based on the center of the circle and Divide the area around the runway, that is: let the coordinate system The second quadrant is area A, the third quadrant is area B, and the coordinate system The fourth quadrant is area C, the first quadrant is area D, and the coordinate system The first quadrant and coordinate system The second quadrant is the E area, so that the coordinate system The fourth quadrant and coordinate system The third quadrant is the F area.

[0175] Furthermore, based on the above-mentioned area division, the air gliding descent point F is determined. n Position landing heading adjustment circle center O fi The method of adjusting the circling direction based on the position and landing heading is as follows:

[0176] When the parking point S is in area A, the gliding point is F1 and the center of the landing course adjustment circle is O. f1 , adjust the landing course and circle left.

[0177] When the parking point S is in area B, the gliding point is F1 and the landing course adjustment circle is O f2 , adjust the landing course and circle right.

[0178] When the parking point S is in area C, the gliding point is F2 and the landing course adjustment circle is O f3 , adjust the landing course and circle left.

[0179] When the parking point S is in the D area, the gliding point is F2 and the landing course adjustment circle is O f4 , adjust the landing course and circle right.

[0180] When the parking point S is in the E zone; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f4 , the landing course adjustment circle turns right; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f1 , adjust the landing course and circle left.

[0181] When the parking point S is in the F area; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f3 , the landing course adjustment circle turns left; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f2 , adjust the landing course and circle right.

[0182] Determine the center of the parking point and adjust the heading circle O sj The method of adjusting the circling direction of the circle is as follows: based on the current determined parking point S and the air gliding point F n Create vector when When the parking point heading adjustment circle is centered at O s2 , the parking point course adjustment circle circles right; when When the parking point heading adjustment circle is centered at O s1 , the parking point heading adjustment circle circles right.

[0183] Example 8

[0184] This embodiment discloses a fixed-wing UAV air glide return strategy and route online planning method, as a preferred embodiment of the present invention, that is, in step S7 of embodiment 3, as shown in FIG. Figure 9 As shown in , when the circling directions of the landing course adjustment circle and the parking point course adjustment circle are consistent, the common tangent of the two circles is the external common tangent; Figure 10 As shown, when the landing course adjustment circle and the parking point course adjustment circle are in opposite directions N1, the common tangent of the two circles is the inner common tangent N2. Based on this, the common tangent is established. And obtaining the coordinates of the tangent point P1 and the tangent point P2 includes the following steps:

[0185] S71, using the current determined parking point heading to adjust the circle center O sj and the landing heading adjustment circle center O fi Create a direction vector

[0186] S72, with the midpoint of the drone runway as the center, construct the center coordinate system O xyz_OO ; Center coordinate system O xyz_OO of Axis direction direction, The axis rotates 90° counterclockwise to point to the center coordinate system O xyz_OO of Axis direction;

[0187] S73, establish the circle center coordinate system O xyz_OO To runway coordinate system O xyz_AB The coordinate transformation matrix L oo2AB ,Right now:

[0188]

[0189] Among them, θ oo2OX is the direction vector and The angle between the axis and the

[0190] S74, establish runway coordinate system O xyz_AB To the center coordinate system O xyz_OO The coordinate transformation matrix L AB2oo ,Right now

[0191] S75, calculate the center O of the parking point heading adjustment circle sj and the landing heading adjustment circle center O fi In the center coordinate system O xyz_OO The coordinates (x Osj_OO ,y Osj_OO ), that is: and

[0192] S76, based on the center O sj and the center O fi In the center coordinate system O xyz_OO According to the circling direction of the parking point heading adjustment circle and the landing heading adjustment circle, the tangent point P1 and the tangent point P2 are calculated in the circle center coordinate system O xyz_OO The coordinates below. Figure 11 As shown, the center coordinate system O xyz_OO Under this situation, the circling directions of the parking point heading adjustment circle and the landing heading adjustment circle are different, and the relative positions of the tangent point P1 and the tangent point P2 are different. Based on this, let the coordinates of the tangent point P1 and the tangent point P2 be expressed as (x P1_OO ,y P1_OO ) and (x P2_OO ,y P2_OO ), that is:

[0193] like Figure 11 As shown in (a), when the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the right, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0194]

[0195]

[0196] like Figure 11 As shown in (b), when the parking point course adjustment circle circles left and the landing course adjustment circle circles left, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0197]

[0198]

[0199] like Figure 11 As shown in (c), when the parking point course adjustment circle circles right and the landing course adjustment circle circles left, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0200]

[0201]

[0202] like Figure 11 As shown in (d), when the parking point course adjustment circle circles to the left and the landing course adjustment circle circles to the right, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0203]

[0204]

[0205] Example 9

[0206] This embodiment discloses a fixed-wing UAV glide return strategy and route online planning method, which, as a preferred implementation of the present invention, includes the following steps:

[0207] S1, with the midpoint of the drone runway as the center, construct a coordinate system for online route planning. Constructing the coordinate system for online route planning includes the following steps:

[0208] S11, construct the northeast celestial coordinate system O with the midpoint of the drone runway as the center xyz_enu ; Among them, the northeast celestial coordinate system O xyz_enu of The axis points to the east, the northeast celestial coordinate system O xyz_enu of The axis points north;

[0209] S12, construct the runway coordinate system O with the midpoint of the drone runway as the center of the circle xyz_AB ; Among them, the runway coordinate system O xyz_AB of Axis points to both ends direction, The axis rotates 90° counterclockwise to point to the runway coordinate system O xyz_AB of Axis direction;

[0210] S13, construct the track coordinate system O with the midpoint of the drone runway as the center of the circle xyz_vk ; Among them, the track coordinate system O xyz_vk of Axis pointing to the track velocity vector when parking direction, The axis rotates 90° counterclockwise to point to the track coordinate system O xyz_vk of Axis direction, track velocity vector when parking Obtained by measuring the onboard inertial navigation sensor.

[0211] S2, obtain the coordinates of the endpoint A, endpoint B and parking point S of the drone runway in the route online planning coordinate system. Specifically, the coordinates of the endpoint A, endpoint B and parking point S in the northeast sky coordinate system O are obtained by calculation. xyz_enu Specifically, endpoint A, endpoint B, and parking point S are collectively referred to as point Q, then:

[0212]

[0213] y Q_enu =[6367449.134-32077×cos(B Q +B0)]×(B Q -B0);

[0214] Among them, (x Q_enu ,y Q_enu ) indicates that point Q is in the northeast celestial coordinate system O xyz_enu The coordinate value of B Q Indicates the latitude of point Q; B0 indicates the latitude of the coordinate origin; L Q represents the longitude of point Q; L0 represents the longitude of the coordinate origin; a and b are both constants, a=6383487.606, b=5357.31.

[0215] S3, establishing a coordinate transformation matrix group within the online route planning coordinate system. Specifically, establishing a coordinate transformation matrix group within the online route planning coordinate system includes the following steps:

[0216] S31, establish the direction vector from endpoint A to endpoint B And use the direction vector Establish runway coordinate system O xyz_AB To the Northeast Celestial Coordinate System Oxyz_enu The coordinate transformation matrix L AB2enu , that is:

[0217]

[0218] Among them, θ AB2OX Represents the direction vector and The angle between the axis and the

[0219] S32, establish the Northeast Celestial Coordinate System O xyz_enu To runway coordinate system O xyz_AB The coordinate transformation matrix L enu2AB , that is:

[0220]

[0221] S33, using the trajectory velocity vector when parking Establish track coordinate system O xyz_vk To runway coordinate system O xyz_AB The coordinate transformation matrix L vk2AB , that is:

[0222]

[0223] Among them, θ vk2O Represents the trajectory velocity vector when parking Direction and The angle between the axis and the

[0224] S34, establish runway coordinate system O xyz_AB To track coordinate system O xyz_vk The coordinate transformation matrix L AB2vk , that is:

[0225] S4, in the online route planning coordinate system, calculate the air gliding point F based on endpoints A and B combined with the coordinate transformation matrix n coordinates, and use air gliding to slide point F n The coordinates of the landing course adjustment circle are calculated as O fi The coordinates of the gliding point F are: n = 1, 2; i = 1, 2, 3, 4. n The coordinates of the position are calculated by the following steps:

[0226] S41, obtain the coordinates of endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below are:

[0227]

[0228]

[0229] Among them, (x A_enu ,y A_enu ) and (x B_enu ,y B_enu ) represent endpoints A and B in the northeast celestial coordinate system O xyz_enu The coordinates below; (x A_AB ,y A_AB ) and (x B_AB ,y B_AB ) are respectively represented as endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below;

[0230] S42, let the air slide down point F n The distance to the nearest endpoint is L, that is, L = h * k; where h is the height of the gliding point relative to the airport runway, and k is the optimal glide ratio of the UAV;

[0231] S43, calculate the air gliding descent point F n The coordinates of , that is:

[0232] When n=1, the air sliding gliding point F1 is on the side of the endpoint A, and the distance from the air sliding gliding point F1 to the endpoint A is L. The coordinate calculation formula is: Among them, (x F1_AB ,y F1_AB ) represents the airborne glide path F1 in the runway coordinate system O xyz_AB The coordinate value of the following;

[0233] When n=2, the air gliding descent point F2 is on the side of the endpoint B, and the distance from the air gliding descent point F2 to the endpoint B is L. The coordinate calculation formula is: Among them, (x F2_AB ,y F2_AB ) represents the gliding point F2 in the runway coordinate system O xyz_AB The coordinate value below.

[0234] Furthermore, the center O of the circle is calculated based on the position of the landing heading adjustment circle. fi coordinates; let the landing heading adjustment circle center O fi In the runway coordinate system O xyz_AB The coordinates below are expressed as (x Ofi_AB ,y Ofi_AB ), the radius of the landing course adjustment circle is R, that is:

[0235] When i=1, the landing course adjustment circle is the upper tangent circle of the airborne glide point F1, and the coordinate calculation formula is:

[0236] When i=2, the landing course adjustment circle is the circle tangent to the glide path F1, and the coordinate calculation formula is:

[0237] When i=3, the landing course adjustment circle is the circle tangent to the glide path F2, and the coordinate calculation formula is:

[0238] When i=4, the landing course adjustment circle is the upper tangent circle of the airborne glide path F2, and the coordinate calculation formula is:

[0239] S5, in the route online planning coordinate system, based on the coordinates of the parking point S and the coordinate conversion matrix, obtain the center O of the parking point heading adjustment circle sj The coordinates of the parking point heading adjustment circle are obtained based on the position of the parking point heading adjustment circle. sj The coordinates of , including the following steps:

[0240] S51, obtain the parking point S in the runway coordinate system O xyz_AB The coordinates (x S_AB ,y S_AB );Right now Among them, (x S_enu ,y S_enu ) indicates that the parking point S is in the northeast celestial coordinate system O xyz_enu The coordinates below;

[0241] S52, obtain the parking point S in the track coordinate system O xyz_vk The coordinates (x S_vk ,y S_vk ),Right now:

[0242] S53, calculate the center O of the heading adjustment circle at the parking point S sj In the track coordinate system O xyz_vk The coordinates (x Osj_vk ,y Osj_vk ), the radius of the parking point heading adjustment circle is r, that is:

[0243] When j=1, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the upper tangent circle at the parking point S is:

[0244] When j = 2, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the tangent circle at the parking point S is:

[0245] S54, obtaining the center O of the parking point heading adjustment circle through coordinate conversion sj In the runway coordinate system O xyz_AB The coordinates (x Osj_AB ,y Osj_AB ),Right now:

[0246] S6, divide the area around the runway, and determine the return strategy based on the state of the UAV when it is parked and the runway area where the parking point S is located, including determining the gliding point F n , landing course adjustment circle center O fi and the center of the parking point heading adjustment circle O sj The position of the runway and the circling direction of the landing course adjustment circle and the parking point course adjustment circle. The area division around the runway includes the following steps:

[0247] S611: Draw perpendicular lines to the runway based on the air gliding points F1 and F2, and establish coordinate systems with F1 and F2 as the center. and

[0248] S612, coordinate system based on the center of the circle and Divide the area around the runway, that is: let the coordinate system The second quadrant is area A, the third quadrant is area B, and the coordinate system The fourth quadrant is area C, the first quadrant is area D, and the coordinate system The first quadrant and coordinate system The second quadrant is the E area, so that the coordinate system The fourth quadrant and coordinate system The third quadrant is the F area.

[0249] Further development, determine the air gliding descent point F n Position landing heading adjustment circle center O fi The method of adjusting the circling direction based on the position and landing heading is as follows:

[0250] When the parking point S is in area A, the gliding point is F1 and the center of the landing course adjustment circle is O. f1 , circling left in landing course adjustment circle;

[0251] When the parking point S is in area B, the gliding point is F1 and the landing course adjustment circle is O f2 , adjust the landing course circle to the right;

[0252] When the parking point S is in area C, the gliding point is F2 and the landing course adjustment circle is O f3, circling left in landing course adjustment circle;

[0253] When the parking point S is in the D area, the gliding point is F2 and the landing course adjustment circle is O f4 , adjust the landing course circle to the right;

[0254] When the parking point S is in the E zone; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f4 , the landing course adjustment circle turns right; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f1 , circling left in landing course adjustment circle;

[0255] When the parking point S is in the F area; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f3 , the landing course adjustment circle turns left; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f2 , adjust the landing course and circle right.

[0256] Further, determine the center O of the parking point heading adjustment circle sj The method of adjusting the circling direction of the circle is as follows: based on the parking point S and the gliding point F n Create vector when When the parking point heading adjustment circle is centered at O s2 , the parking point course adjustment circle circles right; when When the parking point heading adjustment circle is centered at O s1 , the parking point heading adjustment circle circles right.

[0257] S7, based on the air sliding return strategy, for the circle center O sj and the center O fi The parking point heading adjustment circle and the landing heading adjustment circle at the position are used to establish the common tangent of the two circles according to the circling directions of the landing heading adjustment circle and the parking point heading adjustment circle. And obtain the coordinates of the tangent point P1 on the parking point heading adjustment circle and the tangent point P2 on the landing heading adjustment circle. And obtaining the coordinates of the tangent point P1 and the tangent point P2 includes the following steps:

[0258] S71, using the determined parking point heading to adjust the circle center O sj and the landing heading adjustment circle center O fi Create a direction vector

[0259] S72, with the midpoint of the drone runway as the center, construct the center coordinate system O xyz_OO ; Center coordinate system O xyz_OO of Axis direction direction, The axis rotates 90° counterclockwise to point to the center coordinate system O xyz_OO of Axis direction;

[0260] S73, establish the circle center coordinate system O xyz_OO To runway coordinate system O xyz_AB The coordinate transformation matrix L oo2AB ,Right now:

[0261]

[0262] Among them, θ oo2OX is the direction vector and The angle between the axis and the

[0263] S74, establish runway coordinate system O xyz_AB To the center coordinate system O xyz_OO The coordinate transformation matrix L AB2oo ,Right now

[0264] S75, calculate the center O of the parking point heading adjustment circle sj and the landing heading adjustment circle center O fi In the center coordinate system O xyz_OO The coordinates (x Osj_OO ,y Osj_OO ), that is: and

[0265] S76, based on the center O sj and the center O fi In the center coordinate system O xyz_OO According to the circling direction of the parking point heading adjustment circle and the landing heading adjustment circle, the tangent point P1 and the tangent point P2 are calculated in the circle center coordinate system O xyz_OO The coordinates of the tangent point P1 and the tangent point P2 are expressed as (x P1_OO ,y P1_OO ) and (x P2_OO ,yP2_OO ) that is:

[0266] When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the right, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0267]

[0268]

[0269] When the parking point course adjustment circle is circling left and the landing course adjustment circle is circling left, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0270]

[0271]

[0272] When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the left, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0273]

[0274]

[0275] When the parking point course adjustment circle circles left and the landing course adjustment circle circles right, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

[0276]

[0277]

[0278] S8, based on the air sliding return strategy, connect the parking point S, the tangent point P1, the tangent point P2 and the air sliding descent point F in sequence n According to the principle that the straight line between two points is the shortest and the arc is the shortest when there is curvature, the return route of the air taxi that meets the principle of minimum energy loss is generated. The return route of the air taxi that meets the principle of minimum energy loss is generated by transforming the parking point S, the tangent point P1, the tangent point P2 and the air taxi descent point F into the corresponding coordinate transformation matrix. n Convert to the Northeast Celestial Coordinate System O xyz_enu Next, in the northeast sky coordinate system O xyz_enu Next, the connection points S, P1, P2 and F are generated. nThe air sliding return route is the air sliding return route starting from the parking point S, cutting out from the tangent point P1, cutting in from the tangent point P2, and finally sliding down the landing point F. n is the end point. Among them are:

[0279] Get the tangent point P1 and tangent point P2 in the runway coordinate system O xyz_AB The coordinates below are:

[0280]

[0281]

[0282] Get the parking point S, tangent point P1, tangent point P2 and air sliding descent point F n In the northeast celestial coordinate system O xyz_enu The coordinates below are:

[0283]

[0284]

[0285]

[0286]

[0287] Example 10

[0288] This embodiment is based on a fixed-wing UAV air-gliding return strategy and route online planning method disclosed by the present invention, and is involved in practical application. Specifically, this embodiment adopts the following assumptions: the optimal air-gliding ratio of the UAV k = 20, the radius of the landing heading adjustment circle R = 500m, the relative altitude of the air-gliding descent point to the airport h = 60m, the longitude and latitude coordinates of the runway endpoint A (99.7755, 41.3738) and the longitude and latitude coordinates of the endpoint B (99.7906, 41.3881) are all bound by the ground station before takeoff, and the longitude and latitude coordinates of the runway midpoint O are (99.7831, 41.3809). The longitude and latitude coordinates of the UAV position (parking point S) when the engine stops in the air are (99.8421, 41.3526), and the track velocity vector The direction is 40° north by east. Based on this, the specific implementation steps are as follows:

[0289] S1, construct the Northeast Sky coordinate system O xyz_enu Calculate the runway endpoint A, endpoint B and parking point S in the northeast celestial coordinate system O xyz_enu The coordinates under the calculation result are: the coordinates of endpoint A enu =(-631.5675, -794.0369); coordinate B of endpoint B enu =(631.5675, 794.0369); coordinates of parking point Senu =(4940, -3148). Northeast celestial coordinate system O xyz_enu The relative position of the runway between endpoints A and B and the parking point S is as follows: Figure 12 shown.

[0290] S2, build runway coordinate system O xyz_AB and track coordinate system O xyz_vk , calculate the coordinate transformation matrix. Calculate is 51.5°, is 358.5°, then the standard conversion matrix is:

[0291]

[0292]

[0293]

[0294]

[0295] S3, calculate the air gliding descent point F n In the runway coordinate system O xyz_AB The runway endpoint A, endpoint B and parking point S are in the runway coordinate system O xyz_AB The coordinates below are: A AB =(-1015, 0), B AB =(1015,0),S AB =(611, -5826). Calculate the gliding point F n The distance from the nearest runway end is L = 20 × 60 = 1200m, and the glide path points F1 and F2 are obtained in the runway coordinate system O xyz_AB The coordinates below are: F1 AB =(-2215,0) and F2 AB =(2215,0). Runway coordinate system O xyz_AB The relative positions of each point and the runway are as follows: Figure 13 shown.

[0296] S4, calculate the coordinates of the center of the landing heading adjustment circle. Runway coordinate system O xyz_AB Next, the four landing heading adjustment circles have their centers O fi The coordinates are: Of1 AB =(-2215,500),Of2 AB =(-2215,-500),Of3 AB =(2215,-500),Of4 AB =(2215,500).

[0297] S5, calculate the coordinates of the center of the heading adjustment circle of the parking point. Track coordinate system O xyz_vk Next, the coordinates of parking point S are: S vk =(763.5, -5808), then in the track coordinate system O xyz_vk Next, the two parking points are oriented to adjust the center of the circle O. sj The coordinates are: Os1 vk =(763.5, -5308), Os1 vk =(763.5, -6308). Calculate the runway coordinate system O xyz_AB Center of the heading adjustment circle at the lower parking point O sj Coordinates: Os1 AB =(624,-5326),Os2 AB =(598, -6326). Runway coordinate system O xyz_AB The relative positions of the centers of the circles are as follows: Figure 14 shown.

[0298] S6, determine the return strategy. Runway coordinate system O xyz_AB In this case, the parking point S is located in the F region, and the trajectory velocity vector Pointing to the four quadrants of the runway coordinate system, the gliding point is F2; the center of the landing point heading adjustment circle is O f3 , and the landing point heading adjustment circle circles left. Further calculations yield Therefore, the parking point heading adjustment circle circles left, with its center at O s1 .

[0299] S7, generate the air taxi return route. Calculate the center of the circle as O f3 The landing point course adjustment circle is centered at O s1 The common tangent of the parking point heading adjustment circle The coordinates of the tangent points P1 and P2 on the corresponding circles. Since the current landing point heading adjustment circle and the parking point heading adjustment circle are both circling left, the tangent points P1 and P2 are points on the external common tangent line. Construct the circle center coordinate system O xyz_OO , calculated Then the corresponding standard conversion matrix is:

[0300]

[0301]

[0302] Center coordinate system O xyz_OO The coordinates of the tangent points P1 and P2 are: P1 oo =(218, -2760) and P2 oo =(-4864, -2760). Runway coordinate system O xyz_ABBelow, the coordinates of the tangent point P1 and the tangent point P2 are: P1 AB =(2689, -656) and P2 AB =(1099,-5483).

[0303] In summary, the above embodiment assumes that the online planning result of the return route of the air taxi is as follows: Figures 15 to 18 shown.

Claims

1. A fixed-wing UAV glide return strategy and route online planning method, characterized by: The following steps are involved: S1, with the midpoint of the drone runway as the center, build a coordinate system for online route planning; S2, obtain the coordinates of the endpoint A, endpoint B and parking point S of the drone runway in the online route planning coordinate system; S3, establishing a coordinate transformation matrix group within the online route planning coordinate system; S4, in the online route planning coordinate system, calculate the air gliding point F based on endpoints A and B combined with the coordinate transformation matrix n coordinates, and use air gliding to slide point F n The coordinates of the landing course adjustment circle are calculated as O fi Coordinates of; where n represents the position of the glide path point, n = 1, 2; i represents the position of the landing course adjustment circle, i = 1, 2, 3, 4; S5, in the route online planning coordinate system, based on the coordinates of the parking point S and the coordinate conversion matrix, obtain the center O of the parking point heading adjustment circle sj Coordinates of; where j represents the position of the heading adjustment circle of the parking point, j = 1, 2; S6, divide the area around the runway, and determine the return strategy based on the state of the UAV when it is parked and the runway area where the parking point S is located, including determining the gliding point F n , landing course adjustment circle center O fi and the center of the parking point heading adjustment circle O sj The position of the landing course adjustment circle and the circling direction of the parking point course adjustment circle; S7, based on the air sliding return strategy, for the circle center O sj and the center O fi The parking point heading adjustment circle and the landing heading adjustment circle at the position are used to establish the common tangent of the two circles according to the circling directions of the landing heading adjustment circle and the parking point heading adjustment circle. And obtain the coordinates of the tangent point P1 on the parking point heading adjustment circle and the tangent point P2 on the landing heading adjustment circle; S8, based on the air sliding return strategy, connect the parking point S, the tangent point P1, the tangent point P2 and the air sliding descent point F in sequence n According to the principle that the straight line between two points is the shortest and the arc is the shortest when there is curvature, an air-gliding return route that meets the principle of minimum energy loss is generated.

2. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 1, characterized in that: In step S1, constructing the online route planning coordinate system includes the following steps: S11, construct the northeast celestial coordinate system O with the midpoint of the drone runway as the center xyz_enu ; Among them, the northeast celestial coordinate system O xyz_enu of The axis points to the east, the northeast celestial coordinate system O xyz_enu of The axis points north; S12, construct the runway coordinate system O with the midpoint of the drone runway as the center of the circle xyz_AB ; Among them, the runway coordinate system O xyz_AB of Axis points to both ends direction, The axis rotates 90° counterclockwise to point to the runway coordinate system Ox yz_AB of Axis direction; S13, construct the track coordinate system O with the midpoint of the drone runway as the center of the circle xyz_vk ; Among them, the track coordinate system O xyz_vk of Axis pointing to the track velocity vector when parking direction, The axis rotates 90° counterclockwise to point to the track coordinate system O xyz_vk of Axis direction, track velocity vector when parking Obtained by measuring the onboard inertial navigation sensor.

3. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 2, characterized in that: In step S2, the endpoint A, the endpoint B and the parking point S are obtained by calculation in the northeastern sky coordinate system O xyz_enu Specifically, endpoint A, endpoint B, and parking point S are collectively referred to as point Q, then: yes Q_enu =[6367449.134-32077×cos(B Q +B0)]×(B Q -B0); Among them, (x Q_enu ,y Q_enu ) indicates that point Q is in the northeast celestial coordinate system O xyz_enu The coordinate value of B Q Indicates the latitude of point Q; B0 indicates the latitude of the coordinate origin; L Q represents the longitude of point Q; L0 represents the longitude of the coordinate origin; a and b are both constants, a=6383487.606, b=5357.

31.

4. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 3, characterized in that: In step S3, establishing a coordinate transformation matrix group within the route online planning coordinate system includes the following steps: S31, establish the direction vector from endpoint A to endpoint B And use the direction vector Establish runway coordinate system O xyz_AB To the Northeast Celestial Coordinate System O xyz_enu The coordinate transformation matrix L AB2enu , that is: Among them, θ AB2Ox Represents the direction vector and The angle between the axis and the S32, establish the Northeast Celestial Coordinate System O xyz_enu To runway coordinate system O xyz_AB The coordinate transformation matrix L enu2AB , that is: S33, using the trajectory velocity vector when parking Establish track coordinate system O xyz_vk To runway coordinate system O xyz_AB The coordinate transformation matrix L vk2AB , that is: Among them, θ vk2OX Represents the trajectory velocity vector when parking Direction and The angle between the axis and the S34, establish runway coordinate system O xyz_AB To track coordinate system O xyz_vk The coordinate transformation matrix L AB2vk , that is:

5. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 4, characterized in that: In step S4, the air sliding point F n The coordinates of the position are calculated by the following steps: S41, obtain the coordinates of endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below are: Among them, (x A_enu ,y A_enu ) and (x B_enu ,y B_enu ) represent endpoints A and B in the northeast celestial coordinate system O xyz_enu The coordinates below; (x A_AB ,y A_AB ) and (x B_AB ,y B_AB ) are respectively represented as endpoint A and endpoint B in the runway coordinate system O xyz_AB The coordinates below; S42, let the air slide down point F n The distance to the nearest endpoint is L, that is, L = h * k; where h is the height of the gliding point relative to the airport runway, and k is the optimal glide ratio of the UAV; S43, calculate the air gliding descent point F n The coordinates of , that is: When n=1, the air sliding gliding point F1 is on the side of the endpoint A, and the distance from the air sliding gliding point F1 to the endpoint A is L. The coordinate calculation formula is: Among them, (x F1_AB ,y F1_AB ) represents the airborne glide path F1 in the runway coordinate system O xyz_AB The coordinate value of the following; When n=2, the air gliding descent point F2 is on the side of the endpoint B, and the distance from the air gliding descent point F2 to the endpoint B is L. The coordinate calculation formula is: Among them, (x F2_AB ,y F2_AB ) represents the gliding point F2 in the runway coordinate system O xyz_AB The coordinate value below.

6. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 5, characterized in that: In step S4, the center O of the circle is calculated based on the position of the landing heading adjustment circle. fi coordinates; let the landing heading adjustment circle center O fi In the runway coordinate system O xyz_AB The coordinates below are expressed as (x Ofi_AB ,y Ofi_AB ), the radius of the landing course adjustment circle is R, that is: When i=1, the landing course adjustment circle is the upper tangent circle of the airborne glide point F1, and the coordinate calculation formula is: When i=2, the landing course adjustment circle is the circle tangent to the glide path F1, and the coordinate calculation formula is: When i=3, the landing course adjustment circle is the circle tangent to the glide path F2, and the coordinate calculation formula is: When i=4, the landing course adjustment circle is the upper tangent circle of the airborne glide path F2, and the coordinate calculation formula is:

7. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 6, characterized in that: In step S5, the center O of the circle is obtained according to the position of the circle in the direction of the parking point. sj The coordinates of , including the following steps: S51, obtain the parking point S in the runway coordinate system O xyz_AB The coordinates (x S_AB ,y S_AB );Right now Among them, (x S_enu ,y S_enu ) indicates that the parking point S is in the northeast celestial coordinate system O xyz_enu The coordinates below; S52, obtain the parking point S in the track coordinate system O xyz_vk The coordinates (x S_vk ,y S_vk ),Right now: S53, calculate the center O of the heading adjustment circle at the parking point S sj In the track coordinate system O xyz_vk The coordinates (x Osj_vk ,y Osj_vk ), the radius of the parking point heading adjustment circle is r, that is: When j=1, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the upper tangent circle at the parking point S is: When j = 2, the parking point heading adjustment circle is the track velocity vector when parking. The coordinate calculation formula for the tangent circle at the parking point S is: S54, obtaining the center O of the parking point heading adjustment circle through coordinate conversion sj In the runway coordinate system O xyz_AB The coordinates (x Osj_AB ,y Osj_AB ),Right now:

8. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 6, characterized in that: In step S6, dividing the area around the runway includes the following steps: S611: Draw perpendicular lines to the runway based on the air gliding points F1 and F2, and establish coordinate systems with F1 and F2 as the center. and S612, coordinate system based on the center of the circle and Divide the area around the runway, that is: let the coordinate system The second quadrant is area A, the third quadrant is area B, and the coordinate system The fourth quadrant is area C, the first quadrant is area D, and the coordinate system The first quadrant and coordinate system The second quadrant is the E area, so that the coordinate system The fourth quadrant and coordinate system The third quadrant is the F area.

9. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 8, characterized in that: In step S6, determine the air gliding gliding point F n Position landing heading adjustment circle center O fi The method of adjusting the circling direction based on the position and landing heading is as follows: When the parking point S is in area A, the gliding point is F1 and the center of the landing heading adjustment circle is O. f1 , circling left in landing course adjustment circle; When the parking point S is in area B, the gliding point is F1 and the landing course adjustment circle is O f2 , adjust the landing course circle to the right; When parking point S is in zone C; The gliding point of the air gliding is F2 and the landing heading adjustment circle is O f3 , circling left in landing course adjustment circle; When parking spot S is in zone D; The gliding point of the air gliding is F2 and the landing heading adjustment circle is O f4 , adjust the landing course circle to the right; When the parking point S is in the E zone; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f4 , the landing course adjustment circle turns right; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f1 , circling left in landing course adjustment circle; When the parking point S is in the F area; if the track velocity vector Pointing to runway coordinate system O xyz_AB If the first and fourth quadrants are in the gliding direction, the gliding point is F2 and the landing course adjustment circle is O. f3 , the landing course adjustment circle turns left; if the track velocity vector is Pointing to runway coordinate system O xyz_AB The second and third quadrants of the gliding point are F1 and the landing course adjustment circle is O. f2 , adjust the landing course and circle right.

10. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 7, characterized in that: In step S6, the center of the parking point heading adjustment circle O is determined. sj The method of adjusting the circling direction of the circle is as follows: based on the parking point S and the gliding point F n Create vector when When the parking point heading adjustment circle is centered at O s2 , the parking point course adjustment circle circles right; when When the parking point heading adjustment circle is centered at O s1 , the parking point heading adjustment circle circles right.

11. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 7, characterized in that: In step S7, a common tangent line is established. And obtaining the coordinates of the tangent point P1 and the tangent point P2 includes the following steps: S71, using the determined parking point heading to adjust the circle center O sj and the landing heading adjustment circle center O fi Create a direction vector S72, with the midpoint of the drone runway as the center, construct the center coordinate system O xyz_OO ; Center coordinate system O xyz_OO of Axis direction direction, The axis rotates 90° counterclockwise to point to the center coordinate system O xyz_OO of Axis direction; S73, establish the circle center coordinate system O xyz_OO To runway coordinate system O xyz_AB The coordinate transformation matrix L oo2AB ,Right now: Among them, θ oo2OX is the direction vector and The angle between the axis and the S74, establish runway coordinate system O xyz_AB To the center coordinate system O xyz_OO The coordinate transformation matrix L AB2oo ,Right now S75, calculate the center O of the parking point heading adjustment circle sj and the landing heading adjustment circle center O fi In the center coordinate system O xyz_OO The coordinates (x Osj_OO ,y Osj_OO ), that is: and S76, based on the center O sj and the center O fi In the center coordinate system O xyz_OO According to the circling direction of the parking point heading adjustment circle and the landing heading adjustment circle, the tangent point P1 and the tangent point P2 are calculated in the circle center coordinate system O xyz_OO The coordinates of the tangent point P1 and the tangent point P2 are expressed as (x P1_OO ,y P1 x OO ) and (x P2_OO ,y P2_OO ), that is: When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the right, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is: When the parking point course adjustment circle is circling left and the landing course adjustment circle is circling left, is the external common tangent, and the coordinate calculation formula of the tangent point P1 and the tangent point P2 is: When the parking point course adjustment circle is circling to the right and the landing course adjustment circle is circling to the left, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is: When the parking point course adjustment circle circles left and the landing course adjustment circle circles right, For the internal common tangent, the coordinate calculation formula of the tangent point P1 and the tangent point P2 is:

12. A fixed-wing UAV glide return strategy and route online planning method as claimed in claim 11, characterized in that: In step S8, the return route of the air taxi that meets the principle of minimum energy loss is generated by transforming the parking point S, the tangent point P1, the tangent point P2 and the air taxiing descent point F into the corresponding coordinate transformation matrix. n Convert to the Northeast Celestial Coordinate System O xyz_enu Next, in the northeast sky coordinate system O xyz_enu Next, the connection points S, P1, P2 and F are generated. n The air gliding return route.

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