Unmanned aerial vehicle path planning method

Abstract

The invention discloses an unmanned aerial vehicle path planning method, and belongs to the technical field of unmanned aerial vehicle path planning, and the method comprises the following steps: S1, according to the starting point coordinate and the terminal point coordinate of an unmanned aerial vehicle, carrying out the calculation through a Durbin algorithm, and obtaining an original path; s2, replacing a line segment in the middle of the original path with an arc, and enabling a circle where the arc is located to be tangent to a circle where another two arcs are located to obtain a new path; s3, establishing a rectangular plane coordinate system, rotating and translating the new path to the X axis, and respectively calculating to obtain a circle center point coordinate and a radius of a circle where the replacement arc is located, starting point and terminal point coordinates of an original path, and tangent point coordinates of circles where the other two arcs are located and the circle where the replacement arc is located; s4, discrete waypoints of the three arcs in the new path are calculated according to the coordinates of all the points, and multiple discrete waypoint coordinates are obtained; and S5, splicing the plurality of discrete route point coordinates in sequence to obtain a complete route. The unmanned aerial vehicle path planned by the method has higher flexibility and the possibility of avoiding obstacles.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicle (UAV) path planning, and particularly relates to a UAV path planning method. Background Art

[0002] The UAV path planning technology can generate a mission execution flight path for the UAV that satisfies the mission constraints and kinematic constraints from the starting pose point to the ending pose point, enabling the UAV to autonomously execute flight tasks. The kinematic constraints in the UAV path planning technology mainly include: flight speed, turning radius, climb and dive angle, endurance, etc., and the mission constraints mainly include the state of the starting and ending pose points, threat space, etc.

[0003] Currently, common path planning methods include the A* algorithm, the RRT algorithm, and the Dubins algorithm. The A* algorithm is a heuristic search algorithm that introduces an estimated cost function and simultaneously considers the existing expansions, and obtains relatively good points globally through the heuristic information of the estimated cost function. The RRT algorithm will generate a random expansion tree in the given state space with the given starting point as the root node and gradually increase the leaf nodes to reach the target point. These two methods have unique advantages in their respective aspects and can directly obtain discrete track sequences, but their calculation time is too long and they are prone to falling into local optimal solutions, resulting in still large defects in engineering applications. The Dubins algorithm can fully reflect the kinematic ability constraints of the UAV. Usually, the Dubins path consists of "arc segment - straight line segment - arc segment". During the Dubins path planning process, the turning performance ability of the UAV is fully considered, and by constructing continuous curves and straight lines in the two-dimensional plane, an analytical optimal solution that can be found under the premise of the UAV turning maneuver limit is obtained. However, at present, the research on the Dubins algorithm in UAV path planning still has limitations. The continuous path calculated by the Dubins algorithm cannot be directly used as track points to guide the UAV flight and needs to be discretized; in addition, the Dubins algorithm cannot meet the requirement of flying around. Generally, the Dubins algorithm defaults that there is no area that needs to be bypassed between the starting point and the target point. If there are impassable obstacles or dangers in the flight area, the generated Dubins path may not be applicable. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a UAV path planning method.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A UAV path planning method includes the following steps:

[0007] S1. Calculate according to the starting point coordinates and ending point coordinates of the unmanned aerial vehicle (UAV) through the Dubins algorithm to obtain the original path;

[0008] S2. Replace the line segment in the middle of the original path with an arc. The circle where the replaced arc is located is tangent to the circles where the other two arcs are located to obtain a new path;

[0009] S3. Establish a plane rectangular coordinate system, rotate and translate the new path obtained in step S2 onto the X-axis, and calculate respectively to obtain the center point coordinates and radius of the circle where the replaced arc is located, the starting point and ending point coordinates of the original path, and the tangent point coordinates of the circles where the other two arcs are located and the circle where the replaced arc is located;

[0010] S4. Calculate the discrete path points of the three arcs in the new path obtained in step S2 respectively according to the center point coordinates and radius of the circle where the replaced arc is located obtained in step S2, the starting point and ending point coordinates of the original path, and the tangent point coordinates of the circles where the other two arcs are located and the circle where the replaced arc is located to obtain the coordinates of multiple discrete waypoints;

[0011] S5. Concatenate the coordinates of the multiple discrete waypoints obtained in step S3 in sequence to obtain the complete UAV path.

[0012] Preferably, in step S1, the original path is composed of an arc, a line segment and another arc, and the straight line where the line segment part is located is tangent to the circles where the two arcs are located at the same time.

[0013] Preferably, in step S3, the plane rectangular coordinate system is established by taking the direction of the line connecting the center points of the two circles where the other two arcs are located as the positive direction of the X-axis, taking the starting point coordinates of the original path as the coordinate origin, and taking the direction perpendicular to the X-axis as the positive direction of the Y-axis.

[0014] Preferably, in step S3, the calculation formulas for the center point coordinates and radius of the circle where the replaced arc is located, and the tangent point coordinates of the circles where the other two arcs are located and the circle where the replaced arc is located are respectively:

[0015]

[0016] Among them, O 2 is the center point coordinates of the circle where the replaced arc is located, R 1 and R 3 are respectively the radii of the circles where the other two arcs are located, O 1 O 2 is the distance between the center point of the circle where the starting point arc of the original path is located and the center point of the circle where the replaced arc is located, O 1 O 3 is the distance between the center points of the circles where the other two arcs are located, t 0 is the size of the angle formed by the line connecting the O 2 point to the origin and the positive direction of the x-axis, R2 Let \(r\) be the radius of the circle where the replacement arc is located, \(B\) be the tangent point between the circle where the starting arc of the original path is located and the circle where the replacement arc is located, and \(C\) be the tangent point between the circle where the replacement arc is located and the circle where the ending arc of the original path is located. Let \(\overrightarrow{O_1O_2}\) be the vector from the center of the circle where the starting arc of the original path is located to the center of the circle where the replacement arc is located. Let \(\overrightarrow{O_3O_2}\) be the vector from the center of the circle where the ending arc of the original path is located to the center of the circle where the replacement arc is located, and \(|O_1O_2|\) be the distance between the center point of the circle where the starting arc of the original path is located and the center point of the circle where the replacement arc is located. 1 O 2 Let \(|O_2O_3|\) be the distance between the center point of the circle where the ending arc of the original path is located and the center point of the circle where the replacement arc is located. \(O_1\) 3 O 2 Let \(O_2\) be the center point coordinates of the circle where the starting arc of the original path is located, and \(O_3\) 1 be the center point coordinates of the circle where the ending arc of the original path is located. 3 Preferably, step S4 includes the following steps:

[0017] Preferably, step S4 includes the following steps:

[0018] S41. Translate the center of the arc to the origin and divide the arc into multiple arc segments.

[0019] S42. Calculate the starting and ending arc angles of the arc respectively according to the center point coordinates and radius of the circle where the replacement arc is located obtained in step S2, the starting and ending coordinates of the original path, and the tangent point coordinates between the circles where the other two arcs are located and the circle where the replacement arc is located, to obtain the starting arc angle and the ending arc angle.

[0020] S43. Calculate the tangent point coordinates of the multiple arc segments obtained in step S41 according to the starting arc angle obtained in step S42 to obtain the tangent point coordinates of the multiple arc segments.

[0021] S44. Calculate the coordinates of multiple discrete waypoints according to the tangent point coordinates of the multiple arc segments obtained in step S43.

[0022] Preferably, in step S43, the calculation formula for the tangent point coordinates of the arc segment is:

[0023]

[0024] where \(x\) c,k is the abscissa of the tangent point of the arc segment, \(y\) c,k is the ordinate of the tangent point of the arc segment, \(x_0\) S is the abscissa of the center of the circle where the arc is located, \(y_0\) S is the ordinate of the center of the circle where the arc is located, \(r\) S is the radius of the circle where the arc is located, and \(\theta_k\) is the arc angle corresponding to the \(k\)th tangent point of the arc segment.

[0025] Preferably, in step S44, the calculation formula for the discrete waypoint coordinates is as follows:

[0026]

[0027] where x a,k is the abscissa of the discrete waypoint, y a,k is the ordinate of the discrete waypoint, x S is the abscissa of the center of the circle where the arc is located, y S is the ordinate of the center of the circle where the arc is located, is the circular arc angle corresponding to the tangent point of the k-th circular arc segment, is the circular arc angle corresponding to the tangent point of the (k - 1)-th circular arc segment, r S is the radius of the circle where the arc is located, χ k is the turning angle, r k is the length of the line connecting the center of the circle where the arc is located and the discrete waypoint.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The UAV path planning method provided by the present invention replaces the straight line segment in the original Dubins path with an arc segment, can freely adjust the radius in the three arc segments, and gives the waypoints after discretization of the arc segment, making the planned UAV path have higher flexibility and the possibility of avoiding obstacles, thus greatly increasing the feasibility and applicability of the Dubins path;

[0030] (2) The present invention calculates the outer tangent point of the arc by using the tangent point information under the maximum turning angle constraint, thereby discretizing the original continuous curve. The path points after discretization can be directly used as waypoints to guide the UAV to fly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a flowchart of the UAV path planning method provided by the embodiment of the present invention;

[0032] Figure 2 is a Dubins path diagram of four types;

[0033] Figure 3 is a path diagram of the LSL type Dubins path;

[0034] Figure 4 is a new path diagram after transformation of the LSL type Dubins path;

[0035] Figure 5 is R 1 = R 3The new path diagram after the transformation of the LSL-type Dubins path at [time];

[0036] Figure 6 is R 3 > R 1 The new path diagram after the transformation of the LSL-type Dubins path at [time];

[0037] Figure 7 is the path diagram after rotation, flipping and translation;

[0038] Figure 8 is the path diagram after making a perpendicular ray along one side of the track through O 1 , O 3 ;

[0039] Figure 9 is the new path diagram containing the tangent point coordinates;

[0040] Figure 10 is the path diagram with multiple circular arc segments;

[0041] Figure 11 is the path diagram with newly added waypoints;

[0042] Figure 12 is the path diagram at [time];

[0043] Figure 13 is the path diagram containing the positions of each point. Specific implementation manner

[0044] Next, in combination with the Figures 1 to 13 of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0045] As Figure 1 shown, the embodiments of the present invention provide a method for unmanned aerial vehicle path planning, including the following steps:

[0046] S1. According to the starting point coordinates and ending point coordinates of the unmanned aerial vehicle, calculate through the Dubins algorithm to obtain the original path;

[0047] As Figure 2 shown, a typical Dubins path is composed of a circular arc, a line segment and another circular arc. Among them, the straight line where the line segment is located is tangent to the circles where the two circular arcs are located at the same time. Denote the circle where the first circular arc is located as ⊙O 1 , the center of the circle is point O 1 , and the radius is R 1; Denote the circle where the last arc lies as ⊙O 3 , with the center being point O 3 , and the radius being R 3 .

[0048] Calculate the tangent point coordinates of the circle where the starting point lies and the tangent point coordinates of the circle where the ending point lies:

[0049] Taking LSL as an example, as Figure 3 shown:

[0050] From the geometric relationship, it can be obtained that:

[0051]

[0052] Then:

[0053] V 2 = V 1 +(r 2 - r 1 ).n

[0054] Normalize V1 to obtain:

[0055]

[0056] Simplify to obtain:

[0057] V 1n .n = ||V 1n ||.||n||.cosθ = cosθ = c

[0058] Let V 1n =(v 1nx , v 1ny ), n=(n x , n y ), then according to the calculation method of vector rotation, it can be obtained that:

[0059]

[0060] That is:

[0061]

[0062] That is, the tangent point coordinates (x t1 , y t1 ) of the starting point circle are:

[0063] x t1 = x o1 + r 1 * n x

[0064] y t1 = y o1 + r 1 * ny

[0065] The tangent point coordinates (x t2 , y t2 ) of the end circle are as follows:

[0066] x t2 = x o2 + r 2 * n x

[0067] y t2 = y o2 + r 2 * n y

[0068] Among them, V 1 is the vector from the center of the circle where the starting point is located to the center of the circle where the end point is located, V 2 is the vector from the tangent point of the circle where the starting point is located to the tangent point of the circle where the end point is located, n is the unit normal vector of the V 2 vector, (x o1 , y o1 ) is the coordinate of the center of the circle where the starting point is located, (x o2 , y 02 ) is the coordinate of the center of the circle where the end point is located, r 1 is the radius of the circle where the starting point is located, r 2 is the radius of the circle where the end point is located.

[0069] S2. Replace the line segment in the middle of the original path with an arc. The circle ⊙O 2 where the replaced arc BC is located is tangent to the circles ⊙O 1 and the circle ⊙O 3 to obtain a new path;

[0070] The new path is as Figure 4 shown, specifically an LSL-type variant dubins path with the center at point O 2 and a radius of R 2 . Since the parameters of the original dubins path are input conditions, O 1 , O 3 , R 1 , R 3 are known.

[0071] From the tangency relationship between the circles, it can be known that O 1 O 2 - R 1 = R 2 = O 2 O 3 - R 3 . After arrangement, it can be obtained:

[0072] O1 O 2 -O 2 O 3 =R 1 -R 3

[0073] As Figure 5 shown, when R 1 =R 3 , there is O 1 O 2 =O 2 O 3 O, and O 2 is on the perpendicular bisector of the line segment O 1 O 3 . Let R 3 >R 1 . At this time, O 2 is on one side of the hyperbola with O 1 , O , O 3 as the foci. The focal length of the hyperbola 2c = O 1 O 3 , and the eccentricity As Figure 6 shown.

[0074] S3. For a Dubins path of the RSR or LSL type, the centers of the starting and final circular arcs are O 1 , O 3 , and the radii are R 1 , R 3 . Taking the line connecting the centers of the other two circular arcs (i.e., ) as the positive direction of the X-axis, and taking the starting point of the original path as the coordinate origin to establish a plane rectangular coordinate system. By means of orthogonal rotation and translation, the centers O 1 , O 3 of the starting and ending circular arcs of the new path obtained in step S1 are moved to the X-axis, and the midpoint of the two points is located at the origin. As Figure 7 shown, at this time, O 2 satisfying the circle tangency condition is on one side of the hyperbola with O 1 , O 3 as the foci. The focal length of the hyperbola 2c = O 1 O 3 , and the eccentricity Calculate the coordinates of the center point O 2 of the circle ⊙O 2 , the radius R 2 of the circle ⊙O 2 , the coordinates of the starting point A and the ending point D of the original path, the coordinates of the tangent point B of the circle ⊙O 1 and the circle ⊙O 2 , and the coordinates of the tangent point B of the circle ⊙O 2 and the circle ⊙O 3The coordinates of the tangent point C. The specific calculation methods for the coordinates of the above points are as follows:

[0075] Circle ⊙O 2 The center point O of 2 The coordinate parametric equation of:

[0076]

[0077] where t is a parameter, and the angle formed by the line connecting the point at t = t 0 to the origin and the positive x-axis direction is 2π - t 0 . R 3 > R 1 The constraint condition makes the value range of the parameter t be Also, due to the limitation of the actual flight direction, the value range of the parameter is

[0078] At Figure 7 respectively, draw perpendicular rays along one side of the track through O 1 , O 3 to obtain Figure 8 Through Figure 8 it can be seen that when the center point O of the circle ⊙O 2 moves on the hyperbola, the angle change amount of the arc segment of the circle ⊙O 2 is equal to the sum of the angle change amounts of the arc segments of the circle ⊙O 2 , that is: 1 , ⊙O 3 The sum of the angle change amounts of the arc segments, that is:

[0079] Δβ = Δα + Δγ

[0080] where Δβ is the angle change amount of the arc segment of the circle ⊙O 2 , Δα is the angle change amount of the arc segment of the circle ⊙O 1 , and Δγ is the angle change amount of the arc segment of the circle ⊙O 3 .

[0081] For the center O 0 with parameter t 2 , substitute the parameter value t 0 within the domain range to obtain the coordinates of O 2 :

[0082]

[0083] where O 2 is the coordinate of the center point of the circle where the arc BC is located, R 1 and R 3 are the radii of the circles where the other two arcs are located respectively, and the distance between the center points of the circles where the arcs AB and CD are located is O 1 O 3 t0 is O 2 The angle formed by the line connecting point O to the origin and the positive x-axis direction;

[0084] Calculate O through the distance formula between two points 1 O 2 to obtain the radius R of the middle arc segment 2 = O 1 O 2 - R 1 .

[0085] As Figure 9 shown, A and D are respectively the starting point and the ending point of the Dubins path, B is the tangent point of circle O 1 and circle O 2 , C is the tangent point of circle O 2 and circle O 3 . Calculate the coordinates of the starting point A and the ending point D of the original path, the coordinates of the tangent point B of circle ⊙O 1 and circle ⊙O 2 , and the coordinates of the tangent point C of circle ⊙O 2 and circle ⊙O 3 through the following formulas:

[0086] A = known

[0087]

[0088] D = known

[0089] where O 2 is the coordinate of the center point of the circle where arc BC is located, R 1 and R 3 are respectively the radii of the circles where arc AB and arc CD are located, O 1 O 2 is the distance between the center point of the circle where arc AB is located and the center point of the circle where arc BC is located, O 1 O 3 is the distance between the center points of the circles where arc AB and arc CD are located, t 0 is the angle formed by the line connecting point O 2 to the origin and the positive x-axis direction, B is the tangent point of the circle where arc AB is located and the circle where arc BC is located, C is the tangent point of the circle where arc BC is located and the circle where arc CD is located, is the vector pointing from the center of the circle where arc AB is located to the center of the circle where arc BC is located, is the vector pointing from the center of the circle where arc CD is located to the center of the circle where arc BC is located, |O 1 O 2 | is the distance between the center point of the circle where arc AB is located and the center point of the circle where arc BC is located, |O 3 O 2| is the distance between the center point of the circle where arc CD is located and the center point of the circle where arc BC is located, O 1 is the coordinate of the center point of the circle where arc AB is located, O 3 is the coordinate of the center point of the circle where arc CD is located;

[0090] S4. According to the circle ⊙O obtained in step S2 2 of the center point O 2 of the coordinates, the circle ⊙O 2 of the radius R 2 , the starting point A and the ending point D coordinates of the original path, the circle ⊙O 1 and the circle ⊙O 2 of the tangent point B coordinates, the circle ⊙O 2 and the circle ⊙O 3 of the tangent point C coordinates are used to calculate the discrete path points of the arcs AB, BC, and CD in the new path obtained in step S2 respectively, and a plurality of discrete waypoint coordinates are obtained. The specific steps are as follows:

[0091] Since the calculation methods of the discrete path points of arcs AB, BC, and CD are the same, only the calculation method of the discrete path points of one arc will be introduced:

[0092] For different arcs, P S , P A , O S , r S The corresponding points and values are shown in Table 1 below.

[0093] Table 1 Comparison table of parameters for different arc segments

[0094]

[0095] S41. As Figure 10 shown, translate the center of the arc to the origin, and divide the arc into multiple arc segments;

[0096] It can be seen through Figure 10 that on the arc P S P A , it is considered that the center O S is the origin of the coordinate system, the points P S , P A are the starting point and the ending point of this section of the path respectively, and the radius is r S . Considering the maximum turning angle χ max restriction of the UAV, P c,1 , P c,1 , …, P c,5 are the tangent points determined according to the maximum waypoint turning angle. Denote the arc angle direction of the starting point P S as

[0097] S42. Calculate the starting arc angle and the ending arc angle of the arc respectively based on the center point coordinates and radius of the circle where the replacement arc is located obtained in step S2, the starting and ending coordinates of the original path, and the tangent point coordinates of the circles where the other two arcs are located and the circles where the replacement arc is located, specifically as follows:

[0098] For the radian angle of P S calculate its sine and cosine values as:

[0099]

[0100] Through the inverse trigonometric function, the value of can be calculated. Similarly, replace P in the formula with P S to obtain the value of the radian angle of P A A c,k The calculation formula for the arc angle of the tangent point P of the arc segment is:

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] c,k (x c,k , y c,k ) is:

[0108]

[0109] where x c,k is the abscissa of the tangent point of the arc segment, y c,k is the ordinate of the tangent point of the arc segment, x S is the abscissa of the center of the circle where the arc is located, y S is the ordinate of the center of the circle where the arc is located, r S is the radius of the circle where the arc is located, is the arc angle corresponding to the k-th tangent point of the arc segment. k The magnitude of the turning angle χ is:

[0107]

[0108]

[0109] S44. Calculate multiple discrete waypoint coordinates based on the multiple arc segment tangent point coordinates obtained in step S43.

[0110] As shown Figure 11 in, P a,1 , P a,2 , …, P a,5 are the newly added waypoints of the linearized Dubins path. P a,k is on the angle bisector of ∠P a,k- 1 O S P a,k . The straight line P a,k P a,k+1 passes through point P c,k and is tangent to the arc;

[0111] According to the coordinate and central angle relationship between P c,k-1 and P c,k , the coordinates of P a,k (x a,k , y a,k ) are calculated as follows:

[0112]

[0113] where, x a,k is the abscissa of the discrete waypoint, y a,k is the ordinate of the discrete waypoint, x S is the abscissa of the center of the circle where the arc is located, y S is the ordinate of the center of the circle where the arc is located, is the arc angle corresponding to the k-th tangent point of the arc segment, is the arc angle corresponding to the (k - 1)-th tangent point of the arc segment, r S is the radius of the circle where the arc is located, χ k is the turning angle, r k is the length of the line connecting the center of the circle where the arc is located and the discrete waypoint.

[0114] S5. Splice the coordinates of the multiple discrete waypoints obtained in step S3 in sequence to obtain the complete UAV path (route).

[0115] The following demonstrates the UAV path planning method provided by the embodiments of the present invention through actual calculation examples

[0116] Set O 1 = (-10, 0), O 3 = (10, 0), R 1 = 5, R 3 = 7, the starting point coordinates are (-15, 0), the speed direction is vertically upward, the ending point coordinates are (17, 0), the speed direction is vertically downward, and the parametric equation of the coordinates of O 2 is calculated as follows:

[0117]

[0118] Take any one within the range of t value As a demonstration, obtain O 2 = (-1.24, 7.23), R 2 = 6.36 (retaining two significant figures), see Figure 12 .

[0119] According to the UAV path planning method proposed by the embodiment of the present invention, under the condition of the maximum turning angle , the positions of each point are as Figure 13 shown, and the coordinates of each point are shown in Table 2 below.

[0120] Table 2 Specific coordinates of discrete path points

[0121]

[0122]

[0123] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for UAV path planning, characterized in that: The following steps are involved: S1, according to the starting point coordinates and the end point coordinates of the UAV, the original path is calculated by the Dubins algorithm; S2. Replace the line segment in the middle of the original path with an arc, and make the circle where the replaced arc is located tangent to the circles where the other two arcs are located, so as to obtain a new path; S3, establish a plane rectangular coordinate system, rotate and translate the new path obtained in step S2 to the X-axis, and calculate the coordinates of the center point and radius of the circle where the replacement arc is located, the coordinates of the starting point and end point of the original path, and the coordinates of the tangent points of the circles where the other two arcs are located and the circle where the replacement arc is located; S4, according to the coordinates of the center point and radius of the circle where the replacement arc is located obtained in step S2, the coordinates of the starting point and the end point of the original path, and the coordinates of the tangent points of the circles where the other two arcs are located and the circle where the replacement arc is located, respectively calculate the discrete path points of the three arcs in the new path obtained in step S2 to obtain multiple discrete waypoint coordinates; S5. Sequentially concatenate the coordinates of the multiple discrete waypoints obtained in step S3 to obtain a complete drone path.

2. The UAV path planning method according to claim 1, characterized in that: In step S1, the original path is composed of an arc, a line segment and another arc, and the straight line where the line segment is located is tangent to the circles where the two arcs are located at the same time.

3. The UAV path planning method according to claim 1, characterized in that: In step S3, the plane rectangular coordinate system is established by taking the direction of the line connecting the two center points of the other two arcs as the positive direction of the X-axis, the starting coordinates of the original path as the coordinate origin, and the direction perpendicular to the X-axis as the positive direction of the Y-axis.

4. The UAV path planning method according to claim 1, characterized in that: In step S3, the calculation formulas for the coordinates of the center point and radius of the circle where the replacement arc is located, and the coordinates of the tangent points of the circles where the other two arcs are located and the circle where the replacement arc is located are respectively: R2=O1O2-R1 Among them, O2 is the coordinate of the center point of the circle where the replacement arc is located, R1 and R3 are the radii of the circles where the other two arcs are located, O1O2 is the distance between the center point of the circle where the original path starting point arc is located and the center point of the circle where the replacement arc is located, O1O3 is the distance between the center points of the circles where the other two arcs are located, t0 is the angle formed by the line connecting point O2 to the origin and the positive direction of the x-axis, R2 is the radius of the circle where the replacement arc is located, B is the tangent point of the circle where the original path starting point arc is located and the circle where the replacement arc is located, C is the tangent point of the circle where the replacement arc is located and the circle where the original path end point arc is located, is the vector from the center of the circle where the original path starts to the center of the circle where the replacement arc is located. is the vector pointing from the center of the circle where the original path endpoint arc is located to the center of the circle where the replacement arc is located, |O1O2| is the distance between the center point of the circle where the original path starting point arc is located and the center point of the circle where the replacement arc is located, |O3O2| is the distance between the center point of the circle where the original path endpoint arc is located and the center point of the circle where the replacement arc is located, O1 is the coordinate of the center point of the circle where the original path starting point arc is located, and O3 is the coordinate of the center point of the circle where the original path endpoint arc is located.

5. The UAV path planning method according to claim 1, characterized in that: Step S4 comprises the following steps: S41, translating the center of the arc to the origin, and dividing the arc into a plurality of arc segments; S42, calculating the arc angles of the starting point and the ending point of the arc respectively according to the coordinates of the center point and the radius of the circle where the replacement arc is located obtained in step S2, the coordinates of the starting point and the ending point of the original path, and the coordinates of the tangent points of the circles where the other two arcs are located and the circle where the replacement arc is located, to obtain the starting point arc angle and the ending point arc angle; S43, calculating the tangent point coordinates of the multiple arc segments obtained in step S41 according to the starting point arc angle obtained in step S42, to obtain the tangent point coordinates of the multiple arc segments; S44. Calculate the coordinates of multiple discrete waypoints based on the coordinates of the multiple arc segment tangent points obtained in step S43.

6. The UAV path planning method according to claim 5, characterized in that: In step S43, the calculation formula of the arc segment tangent point coordinates is: Among them, x c,k is the horizontal coordinate of the arc segment tangent point, y c,k is the ordinate of the point of tangency of the arc segment, x S is the horizontal coordinate of the center of the circle where the arc is located, y S is the ordinate of the center of the circle where the arc is located, r S is the radius of the circle where the arc lies, is the arc angle corresponding to the tangent point of the kth arc segment.

7. The UAV path planning method according to claim 5, characterized in that: In step S44, the calculation formula of the discrete waypoint coordinates is: Among them, x a,k is the horizontal coordinate of the discrete waypoint, y a,k is the ordinate of the discrete waypoint, x S is the horizontal coordinate of the center of the circle where the arc is located, y S is the ordinate of the center of the circle where the arc lies, is the arc angle corresponding to the tangent point of the kth arc segment, is the arc angle corresponding to the tangent point of the k-1th arc segment, r S is the radius of the circle where the arc lies, χ k is the turning angle, r k It is the length of the line connecting the center of the circle where the arc is located and the discrete waypoint.

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