A Method for Generating an 8-Shaped Flight Path of an Unmanned Aerial Vehicle

Abstract

The present invention provides a method for generating an 8-shaped flight path of an unmanned aerial vehicle, comprising the following steps: determining relevant parameters in the 8-shaped flight path according to the mission situation, determining the length of the straight line and the coordinates of the endpoints; forming a navigation point data packet for the 8-shaped flight path, and the unmanned aerial vehicle planning and calculating the flight path according to the data in the data packet during flight; determining whether the unmanned aerial vehicle is in the defined 8-shaped flight path according to its actual position, if so, proceeding to the next step, if not, using the coordinates of the straight line endpoints or intersection points in the 8-shaped flight path as the end point of the flight path, flying after generating the flight path, and proceeding to the next step after reaching the end point; determining the representative position of the unmanned aerial vehicle in the 8-shaped flight path; and judging in real time whether the unmanned aerial vehicle has flown over the end point of the current theoretical flight path. The present invention can quickly, flexibly and conveniently generate 8-shaped flight paths with different headings, different radii and different sizes, meeting the diversified requirements for flight path changes during the mission execution of the unmanned aerial vehicle.

Description

Technical Field

[0001] The present invention belongs to the technical field of overall design of unmanned aerial vehicles, and particularly relates to a method for generating an 8-shaped flight path of an unmanned aerial vehicle. Background Art

[0002] Low-dynamic aircraft represented by high-altitude long-endurance unmanned aerial vehicles often need to fly in an 8-shaped flight path during the process of carrying loads to perform tasks, so as to achieve functions such as persistent ground surveillance, technical reconnaissance, communication relay, etc. At present, when designing the flight path of an unmanned aerial vehicle, it is usually achieved by pre-binding a series of navigation points to fly along the expected flight path. The navigation points are connected by straight lines, and information such as the turning radius and task attributes (such as retracting / extending the landing gear, turning on the task load switch) during the transition between straight lines is defined at the navigation points.

[0003] To achieve an 8-shaped flight path, there are mainly two traditional generation methods. One is to define a series of navigation points to approximately form an 8-shaped shape, and the unmanned aerial vehicle flies in a straight line between the navigation points and passes through these navigation points in sequence to finally form an 8-shaped flight path composed of multiple short straight line segments; the other is to define a certain navigation point as a hovering point, and through algorithmic logic control, the unmanned aerial vehicle circles clockwise and counterclockwise alternately when passing through this navigation point to form an 8 composed of two externally tangent circles. The first method above requires a large number of navigation points, is inconvenient to use, and has poor operability; the second method is simple, practical, vivid and intuitive, but due to the use of a periodic motion flight path composed of two circles, it cannot effectively adjust the heading, radius and size of the 8-shaped flight path. For example, when it is necessary to make the unmanned aerial vehicle fly against the wind in a certain direction or fly with its back to the sun, or when it is necessary to continuously adjust the flight path size and arc radius of the unmanned aerial vehicle, etc., the traditional 8-shaped flight path is not flexible enough and cannot easily meet the requirements of variable heading, variable radius and variable size. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a device and method for generating an 8-shaped flight path of an unmanned aerial vehicle. The solution of the present invention can solve the problems existing in the above prior art.

[0005] The technical solution of the present invention:

[0006] A method for generating an 8-shaped flight path of an unmanned aerial vehicle, comprising the following steps:

[0007] Determine the coordinates of the intersection point of two intersecting straight lines in the 8-shaped flight path, the heading angle of the straight line, and the radii of two symmetric arc segments of the 8-shaped shape according to the task situation, and determine the length of the straight line and the coordinates of the endpoints;

[0008] Construct an 8-shaped flight path navigation point data packet according to the coordinates of the straight line endpoints, the coordinates of the straight line intersection point, and the navigation point information, and the unmanned aerial vehicle plans and calculates the flight path according to the data in the data packet during flight;

[0009] Determine whether the UAV is in the defined figure-eight flight path according to its actual position. If it is, proceed to the next step; if not, use the coordinates of the straight-line endpoints or intersection points in the figure-eight flight path as the end point of the flight path, generate the flight path and fly. After reaching the end point, proceed to the next step;

[0010] Determine the representative position of the UAV in the figure-eight flight path according to the actual position of the UAV and the position of the defined figure-eight flight path;

[0011] According to the representative position of the UAV's current position in the defined figure-eight flight path, determine in real time whether the UAV has flown past the end point of the current theoretical flight path.

[0012] Furthermore, the data in the navigation point data packet includes navigation point information and line segment information between navigation points. The navigation point information includes the coordinates of the four endpoints of the straight line segment and the angle between the straight line segment and the axis of symmetry of the figure-eight flight path. The line segment information between navigation points includes the length and curvature of the line segment.

[0013] Furthermore, the method for determining the representative position of the UAV in the defined figure-eight flight path is as follows:

[0014] S4.1 Taking the coordinates of the center point of the figure-eight flight path as a reference, calculate the actual coordinates of the UAV's actual position relative to this reference point in the north-east-earth coordinate system;

[0015] S4.2 Determine whether the UAV is on a straight line segment or a curve segment in the figure-eight flight path according to the actual coordinates of the UAV and the curvature in its data packet. If it is on a straight line segment, proceed to S4.3; if it is on a curve segment, proceed to S4.4;

[0016] S4.3 Taking the current position of the UAV as the center of a circle, draw a circle with a radius of R L There are three relative positions between the drawn circle and the straight line segment in the figure-eight flight path. One is no intersection, one is one intersection, and one is two intersections. When the relative position is no intersection and one intersection, take the point on the straight line segment in the figure-eight flight path closest to the UAV's position as the representative position of the UAV in the figure-eight flight path. When the relative position is two intersections, take the intersection point of the straight line segment along the flight direction as the representative position of the UAV in the figure-eight flight path;

[0017] S4.4 Taking the current position of the UAV as the center of a circle, draw a circle with a radius of R LDraw a circle with a radius. There are three relative positions between the drawn circle and the curve segment in the figure-eight trajectory. One is no intersection, one is one intersection, and one is two intersections. When the relative position is no intersection or one intersection, take the curve point in the figure-eight trajectory closest to the UAV's position as the UAV's represented position in the figure-eight trajectory. When the relative position is two intersections, take the intersection on the curve along the forward direction of the flight path as the UAV's represented position in the figure-eight trajectory.

[0018] Further, the R L is a given value determined according to the characteristics of the UAV itself. Reducing this value can make the UAV correct more quickly towards the theoretical flight path after deviating from it, enhance the control response ability, and improve the tracking accuracy, but it may bring instability to the control system. On the contrary, increasing this value can ensure the stability of the control system, but it may make the control response force of the UAV insufficient and fail to meet the expected tracking expectation.

[0019] Further, if the UAV performs repeated flights along the same figure-eight trajectory, set the end point of the previous figure-eight trajectory as the starting point and repeat the recording in the data packet.

[0020] Further, when the UAV performs flights along different figure-eight trajectories, revise the figure-eight flight direction, the radius of the figure-eight arc segment, and the figure-eight size to obtain the revised figure-eight trajectory, and then generate the flight path according to the described method for generating a UAV figure-eight trajectory.

[0021] Advantages of the present invention compared with the prior art:

[0022] The present invention parametrically describes the figure-eight trajectory through three variables: the figure-eight flight direction, the radius of the figure-eight arc segment, and the figure-eight size. It can quickly, flexibly, and conveniently generate figure-eight trajectories with different flight directions, different radii, and different sizes, overcoming the disadvantages in traditional figure-eight trajectories that cannot effectively change the flight direction, radius, and size, and meeting the diverse requirements for flight path changes during the UAV's mission execution. Brief Description of the Drawings

[0023] The accompanying drawings included are used to provide a further understanding of the embodiments of the present invention. They form a part of the description and are used to illustrate the embodiments of the present invention and, together with the written description, explain the principles of the present invention. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0024] Figure 1 Shows a schematic diagram of the steps of a method for generating a UAV figure-eight trajectory according to an embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of 8-shaped parameterization in a method for generating an 8-shaped flight path with variable course, variable radius and variable size provided by an embodiment of the present invention;

[0026] Figure 3 It is a schematic diagram of a flight path with variable course in a method for generating an 8-shaped flight path with variable course, variable radius and variable size provided by an embodiment of the present invention;

[0027] Figure 4 It is a schematic diagram of a flight path with variable course and variable radius in a method for generating an 8-shaped flight path with variable course, variable radius and variable size provided by an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of a flight path with variable course, variable radius and variable size in a method for generating an 8-shaped flight path with variable course, variable radius and variable size provided by an embodiment of the present invention. Detailed implementation manners

[0029] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restrictive of the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that for ease of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0032] As Figure 1 shown, according to an embodiment of the present invention, a method for generating an 8-shaped flight path of a drone is provided, including the following steps:

[0033] Step 1, determine the coordinates of the intersection point of the two intersecting straight lines in the 8-shaped flight path, the heading angles of the straight lines, and the radii of the two symmetric arc segments of the 8-shaped according to the mission situation, and determine the length of the straight line and the coordinates of the endpoints;

[0034] Given the longitude, latitude, and altitude coordinates (x0, y0, z0) of the intersection point (i.e., the center point of the 8-shaped) of the two intersecting straight lines in the variable-heading variable-radius variable-size 8-shaped flight path, the radius R of the two symmetric arc segments of the 8-shaped, and the clockwise angle between the symmetric central axis of the 8-shaped (i.e., the straight line where the centers of the two arc segments are connected) and the due north direction in the ground north-east-earth coordinate system (i.e., the heading angle) The distance L between the two intersection points after the symmetric central axis of the 8-shaped and the two arc segments intersect (i.e., the size of the 8-shaped flight path). In one embodiment, to ensure that the 8-shaped flight path includes a straight line segment, generally L≥5R can be taken in parameter selection. If the restriction L≥5R is removed and L = 4R is set, a traditional 8-shaped flight path formed by two externally tangent circles can be generated. All longitude and latitude coordinates involved in the present invention are coordinates in the standard WGS84 coordinate system.

[0035] Calculate the lengths L1 and L3 of the two equal-length straight line segments in the 8-shaped flight path, and the heading angles of the two straight line segments and Calculate the lengths L2 and L4 of the two equal-length arc segments in the 8-shaped flight path, and the used formula is as follows.

[0036]

[0037] L2 = L4 = R(2μ + π)

[0038]

[0039]

[0040] where μ is the angle between the central axis and a straight line segment in the figure-eight, and μ, and are in radians, and are in degrees. The mod is the modulo operator, used to ensure that and are within the specified range of [0, 2π].

[0041] Calculate the coordinates of the 4 endpoints of the two straight line segments of the figure-eight trajectory. The calculation formula is as follows.

[0042]

[0043] Step 2: Construct a figure-eight trajectory navigation point data packet based on the coordinates of the straight line endpoints, the coordinates of the straight line intersection point, and the information of the navigation points. When the UAV is flying, it plans and calculates the trajectory according to the data in the data packet;

[0044] Furthermore, in one embodiment, the data in the navigation point data packet includes the navigation point information traj_points and the line segment information traj_curves between the navigation points. The navigation point information includes the coordinates of each navigation point (i.e., the four endpoints of the straight line segment) on the north axis X and the east axis Y in the north-east-earth coordinate system and the angle between the straight line segment and the symmetry axis of the figure-eight trajectory, that is, the heading value. The line segment information between the navigation points includes the length and curvature of each line segment; the length of the line segment between the navigation points is used to assist in calculating where the UAV's current position is on this line segment, and the curvature is used to determine the center of the circle for generating the arc segment curve.

[0045] In one embodiment, to enable the UAV to continuously fly in a cyclic and periodic manner on the proposed figure-eight trajectory, it is necessary to repeatedly add the information of the first line at the end of the navigation point data packet, thereby obtaining 5 navigation points. The 5 navigation points are sequentially connected in order and respectively correspond to 4 line segments. The endpoints of each line segment are the starting point and the ending point of this section of the trajectory, corresponding to the 5 navigation points in sequence.

[0046]

[0047] Furthermore, in one embodiment, the present invention uses a conventional and mature Dubins curve generation algorithm to achieve a smooth transition of the tangent arc curve between two straight lines.

[0048] Step 3: Determine whether the UAV is on the defined figure-eight flight path according to its actual position. If it is, proceed to the next step; if not, use the coordinates of the straight-line endpoints or intersection points on the figure-eight flight path as the end point of the flight path, generate the flight path and fly. After reaching the end point, proceed to the next step;

[0049] Step 4: Determine the representative position of the UAV on the figure-eight flight path according to its actual position and the position of the defined figure-eight flight path;

[0050] Further, in one embodiment, the method for determining the representative position of the UAV on the defined figure-eight flight path is as follows:

[0051] S4.1: Taking the coordinates of the center point of the figure-eight flight path as a reference, calculate the actual coordinates of the UAV's actual position relative to this reference point in the north-east-earth coordinate system;

[0052] In one embodiment, taking the longitude, latitude, and altitude coordinates (x0, y0, z0) of the center point of the figure-eight as a reference point, calculate the coordinates (x uav , y uav ) of the UAV's current longitude and latitude position relative to this reference point in the north-east-earth coordinate system (x u ′ av , y u ′ av ). The calculation formula is as follows:

[0053] x u ′ av =(x uav -x0)(R m +z0)

[0054] y u ′ av =(y uav -y0)(R n +z0)cos(x0)

[0055] e2 = b*(2 - b)

[0056]

[0057]

[0058] where a = 6378137.0 and b = 1 / 298.257223563.

[0059] S4.2: Determine whether the UAV is on the straight-line segment or the curve segment of the figure-eight flight path according to its actual coordinates and the curvature in its data packet. If it is on the straight-line segment, proceed to S4.3; if it is on the curve segment, proceed to S4.4;

[0060] When the drone flies into the defined figure-eight flight path, since its actual position usually has a certain deviation from the theoretical flight path, it is necessary to calculate the representative position of the drone's current position on the straight line segment or arc segment of the theoretical flight path according to the traj_points and traj_curves information. If the curvature of the theoretical flight path corresponding to the representative position of the drone's current position is 0, it means that the defined figure-eight flight path where the drone is located is a straight line; if it is judged that the curvature of the theoretical flight path corresponding to the representative position of the drone's current position is not equal to 0, it means that the defined figure-eight flight path where the drone is located is a curve.

[0061] S4.3 Draw a circle with the current position of the drone as the center and a radius of R L The relative position of the drawn circle and the straight line segment in the figure-eight flight path has three cases: one is no intersection, one is one intersection, and one is two intersections; when the relative position is no intersection and one intersection, take the point on the straight line segment in the figure-eight flight path that is closest to the drone's position as the representative position of the drone in the figure-eight flight path When the relative position is two intersections, take the intersection of the straight line segment along the forward direction as the representative position of the drone in the figure-eight flight path

[0062] The calculation formula is as follows:

[0063]

[0064]

[0065] Among them, S0 and D are intermediate calculation process variables, indicating the distance from the representative position of the drone on the theoretical flight path to the starting point of the theoretical flight path, x start and y start are the starting point coordinates of this section of the theoretical straight flight path respectively.

[0066] In one embodiment, R Lis a given value, which comes from the L1-navigation algorithm proposed by S. Park in 2004 (see the literature Park, S., Deyst, J., and How, J. P., “A New Nonlinear Guidance Logic for Trajectory Tracking,” AIAA Guidance, Navigation, and Control Conference and Exhibit, Aug. 2004.). This value directly affects the expected turning rate of the UAV and thus affects the aileron deflection. Reducing this value can enable the UAV to correct more quickly towards the theoretical flight path after deviating from it, enhance the control response ability, and improve the tracking accuracy, but it may bring instability to the control system. Conversely, increasing this value can ensure the stability of the control system, but it may cause the control response of the UAV to be insufficient and fail to achieve the expected tracking expectation. Considering the characteristics of the UAV itself, the value of this parameter varies. For low-speed aircraft, it is generally in the order of hundreds of meters (150m - 300m).

[0067] S4.4 With the current position of the UAV as the center, draw a circle with radius R L There are three relative positions between the drawn circle and the curve segment in the figure-eight flight path: one is no intersection, one is one intersection, and one is two intersections; when the relative position is no intersection and one intersection, take the curve point in the figure-eight flight path closest to the UAV position as the representative position of the UAV in the figure-eight flight path; when the relative position is two intersections, take the intersection on the forward curve as the representative position of the UAV in the figure-eight flight path.

[0068] In the theoretical curve flight path, according to the curvature R′ of the curve, the corresponding center coordinates (x center , y center ) can be solved. Then, according to the current position of the UAV and the starting position of the theoretical curve flight path, their polar coordinates (θ uav , ρ uav ) and (θ start , ρ start ) relative to the curve center are solved respectively. The calculation formulas are as follows

[0069]

[0070] where seg represents the serial number of the current flight segment curve on the defined theoretical flight path, sign represents the sign function, if its parameter is negative, take -1, if its parameter is 0, take 0, if its parameter is positive, take 1, represents the heading of the seg-th flight path segment, represents the position of the UAV represented on the theoretical flight path, Indicates the distance from the position represented by the UAV on the theoretical flight path to the starting point of the theoretical flight path, x start and y start are respectively the starting point coordinates in this section of the theoretical straight flight path.

[0071] Step Five: According to the position represented by the UAV at its current position in the defined figure-eight flight path, determine in real time whether the UAV has flown past the end point of the current theoretical flight path.

[0072] Further, in an embodiment, it is determined whether the UAV has flown past the end point of the theoretical flight path based on whether the distance of the UAV from its position represented on the current theoretical flight path is greater than the length traj_curves(seg, 1) of the current theoretical flight segment seg. The calculation formula is as follows.

[0073]

[0074] According to the definition and corresponding method of traj_points and traj_curves in Step 4, the method of setting the flown end point as the starting point and the next point in the original flight path information as the end point can be achieved by adding 1 to the current flight segment number seg of the flight path. If it is necessary to fly in a loop along the figure-eight flight path, it needs to be further achieved by taking the remainder. The calculation formula is as follows.

[0075]

[0076] Among them, seg is the line segment number of the current flight segment of the UAV, traj_N represents the number of navigation points. For the figure-eight flight path defined in the present invention, the value of traj_N is 4, and mod is the remainder operator. Whether it is necessary for the UAV to fly in a loop along the set flight path can be achieved by sending a remote control command on the ground. Jumping out of the figure-eight flight path and making the UAV fly to other flight paths can also be achieved by sending a remote control command on the ground.

[0077] Further, when the UAV performs different figure-eight flight paths, the revised figure-eight flight path is obtained by revising the figure-eight course, the radius of the figure-eight arc segment, and the figure-eight size, and then the flight path is generated according to the described method for generating a UAV figure-eight flight path.

[0078] In order to have a further understanding of the method for generating a UAV figure-eight flight path provided by the present invention, the following will be described in detail with specific examples and accompanying drawings.

[0079] First, assume that an eight-shaped flight path needs to be executed in a certain area according to the flight mission. After on-site measurement, the geodetic coordinates of the center point of the eight-shaped flight path are set as (23.70987991°, 103.81817501°, 1700 m), the heading of the eight-shaped path is 137.7°, the radius of the circular arc segment of the eight-shaped path is 1500 m, and the size of the eight-shaped path is 8000 m.

[0080] Combined with Figure 2 It can be seen that in the defined eight-shaped flight path, the lengths L1 and L3 of the two symmetric straight-line segments (numbered ① and ③) are both 4000 m and the curvature is 0, and the lengths L2 and L4 of the two symmetric circular arc segments (numbered ② and ④) are both 6642.89 m and the curvatures are -0.00067 and 0.00067 respectively, where a positive curvature indicates counterclockwise circular arc flight and a negative curvature indicates clockwise circular arc flight.

[0081] According to the calculation formula in the above invention content, the navigation point information traj_points of the eight-shaped flight path and the line segment information traj_curves between the navigation points are obtained as follows

[0082]

[0083] Then, perform the logical judgment and calculation during the UAV flight process according to the above invention content.

[0084] Figure 3 The schematic diagram of the variable-heading eight-shaped flight path generated by the eight-shaped flight path generation method proposed by the present invention is given. The UAV flies with a fixed eight-shaped size of 8000 m as a parameter and a fixed circular arc radius of 1500 m as a parameter. According to the mission requirements, the heading is switched from 100° to 200° and then to 300°. It can be seen that the UAV switches according to the required heading angle with the center point of the eight-shaped flight path as the center, and flexibly executes the variable-heading eight-shaped flight path mission.

[0085] Furthermore, in one embodiment, Figure 4 The schematic diagram of the variable-heading and variable-radius eight-shaped flight path generated by the eight-shaped flight path generation method proposed by the present invention is given. The UAV flies with a fixed eight-shaped size of 10000 m as a parameter. According to the mission requirements, the heading is switched from 100° to 200° and then to 300°, and the corresponding radius of the circular arc segment is also switched from 1000 m to 1500 m and then to 2000 m. It can be seen that the UAV switches according to the required heading angle and the radius of the circular arc segment with the center point of the eight-shaped flight path as the center, and flexibly executes the variable-heading and variable-radius eight-shaped flight path mission.

[0086] Furthermore, in one embodiment, Figure 5Fig. 0 shows a schematic diagram of an eight-shaped trajectory with variable heading, variable radius, and variable size generated by using the eight-shaped trajectory generation method proposed by the present invention. During the flight of the UAV, according to the mission requirements, the heading is switched from 100° to 200° and then to 300° respectively. The corresponding arc segment radii are also switched from 1000 m to 1500 m and then to 2000 m respectively. The corresponding eight-shaped sizes are also switched from 5000 m to 8000 m and then to 10000 m respectively. It can be seen that the UAV switches according to the required heading angle, arc segment radius, and size parameters with the center of the eight-shaped trajectory as the center, and flexibly executes the flight mission of the eight-shaped trajectory with variable heading, variable radius, and variable size.

[0087] It should be noted that the present invention uses a mature Dubins curve algorithm to automatically generate a smooth tangent transition arc curve between straight line segments. This kind of transition requires a small segment of trajectory adjustment, which is also the reason for the appearance of a small part of irregular curves or straight lines with lateral intersections during the switching transition of eight-shaped trajectories with different headings, different radii, or different sizes. Affected by factors such as flight missions and changes in the external environment, the switching points for the UAV to execute different eight-shaped trajectories during flight may occur at any position of the current eight-shaped trajectory. The Dubins curve can flexibly, quickly, and conveniently adapt to this arbitrariness and randomness, and is a relatively practical and mature engineering method. In other embodiments, appropriate calculation methods can be selected according to needs. Figures 2 to 4 According to an embodiment, a UAV is provided, and the eight-shaped trajectory generation method of the present invention is used for trajectory planning.

[0088] In summary, the eight-shaped trajectory of the UAV provided by the present invention has at least the following advantages compared with the prior art:

[0089] The present invention parametrically describes the eight-shaped trajectory through three variables: the eight-shaped heading, the eight-shaped arc segment radius, and the eight-shaped size, and can quickly, flexibly, and conveniently generate eight-shaped trajectories with different headings, different radii, and different sizes, overcoming the disadvantages of the traditional eight-shaped trajectory that cannot effectively change the heading, radius, and size, and meeting the diversified requirements for trajectory changes during the mission execution of the UAV.

[0090] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0091] ​

Claims

1. A method for generating an 8-shaped flight path of an unmanned aerial vehicle, characterized in that, It includes the following steps: Determine the coordinates of the intersection point of the two intersecting straight lines in the figure-eight flight path, the course angle of the straight line, and the radii of the two symmetric arc segments of the figure-eight according to the mission situation. Determine the length of the straight line and the coordinates of the endpoints, and take L≥5R, where R is the radius of the two symmetric arc segments of the figure-eight, and L is the distance between the two intersection points after the two arc segments intersect; Construct a figure-eight flight path navigation point data packet based on the coordinates of the straight line endpoints, the coordinates of the straight line intersection point, and the navigation point information. When the UAV is flying, it plans and calculates the flight path according to the data in the data packet; Determine whether the UAV is in the defined figure-eight flight path according to its actual position. If it is, proceed to the next step. If not, use the coordinates of the straight line endpoints or intersection point in the figure-eight flight path as the end point of the flight path, generate the flight path and fly. After reaching the end point, proceed to the next step; Determine the representative position of the UAV in the figure-eight flight path according to the actual position of the UAV and the position of the defined figure-eight flight path; The method for determining the representative position of the UAV in the defined figure-eight flight path is as follows: S4.1 Take the coordinates of the center point of the figure-eight flight path as the reference point, and calculate the actual coordinates of the UAV's actual position relative to this reference point in the north-east-earth coordinate system; S4.2 Determine whether the UAV is in the straight line segment or the curve segment of the figure-eight flight path according to the actual coordinates of the UAV and the curvature in its data packet. If it is in the straight line segment, proceed to S4.

3. If it is in the curve segment, proceed to S4.4; S4.3 With the current position of the drone as the center, draw a circle with a radius of R L There are three relative positions between the drawn circle and the straight-line segment in the figure-eight flight path. One is no intersection, one is one intersection, and one is two intersections. When the relative position is no intersection or one intersection, take the point on the straight-line segment in the figure-eight flight path that is closest to the drone's position as the representative position of the drone in the figure-eight flight path. When the relative position is two intersections, take the intersection of the straight-line segment along the forward direction of the flight path as the representative position of the drone in the figure-eight flight path; S4.4 With the current position of the drone as the center, draw a circle with a radius of R L There are three relative positions between the drawn circle and the curved segment in the figure-eight flight path: one is no intersection, one is one intersection, and one is two intersections. When the relative position is no intersection or one intersection, take the curve point in the figure-eight flight path that is closest to the drone's position as the representative position of the drone in the figure-eight flight path. When the relative position is two intersections, take the intersection point on the curve along the forward direction of the flight path as the representative position of the drone in the figure-eight flight path; According to the representative position of the UAV's current position in the defined figure-eight flight path, determine in real time whether the UAV has flown past the end point of the current theoretical flight path.

2. The method for generating an 8-shaped flight path of an unmanned aerial vehicle according to claim 1, characterized in that, The data in the navigation point data packet includes navigation point information and the line segment information between navigation points. The navigation point information includes the coordinates of the four endpoints of the straight line segment and the angle between the straight line segment and the symmetry axis of the figure-eight flight path. The line segment information between navigation points includes the length and curvature of the line segment.

3. The method for generating an 8-shaped flight path of an unmanned aerial vehicle according to claim 2, characterized in that, If the UAV flies the same figure-eight flight path repeatedly, set the end point of the previous figure-eight flight path as the start point and record it repeatedly in the data packet.

4. The method for generating an 8-shaped flight path of an unmanned aerial vehicle according to claim 3, characterized in that, When the UAV flies different figure-eight flight paths, obtain the revised figure-eight flight path by revising the figure-eight course, the radius of the figure-eight arc segment, and the figure-eight size, and then generate the flight path according to the described method for generating a UAV figure-eight flight path.

5. An unmanned aerial vehicle, characterized in that, Use the method described in any one of claims 1 to 4 for flight path planning.

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