Drone follow-the-line flight waypoint search method, flight path planning method and system

Abstract

The application discloses a kind of unmanned plane line simulation flight waypoint search method, route planning method and system, comprising: first, the center line discrete point sequence of the inspection road is obtained, and the waypoint spacing of line simulation flight route is set.Then according to the center line discrete point sequence, the direction vector of the to-be-searched polyline segment is determined.After that, according to the current waypoint coordinate, direction vector and waypoint spacing, the coordinates of candidate waypoint are determined, and whether the candidate waypoint is on the to-be-searched polyline segment is verified.If yes, the candidate waypoint is included in the waypoint set, and the candidate waypoint is used as the current waypoint to continue searching the next waypoint.If no, the remaining distance that needs to be moved after moving to the end point of the to-be-searched polyline segment is calculated, and the target line segment is searched out.Finally, the waypoint that meets the waypoint spacing is searched out by combining the direction vector and starting point coordinate of the target line segment, the remaining distance, so as to automatically generate line simulation inspection waypoint, improve the line simulation flight inspection route planning efficiency of long linear road unmanned plane.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of three-dimensional channel control, in particular to a method and system for searching for flight waypoints of an unmanned aerial vehicle (UAV) in line flight. BACKGROUND

[0002] Traditional UAV road inspection routes are usually planned manually point by point, and the planning of long linear road UAV inspection routes is complex. The planning personnel are required to have high professional skills, and the flight yaw angle cannot be automatically adjusted according to the road direction, which causes the image to deviate from the direction of the road, and the two-way lane coverage is not complete. The UAV position cannot be associated with the road vector data, and the UAV route parameters cannot be automatically calculated, which causes the UAV to deviate from the inspection target in curved roads and branch junctions. SUMMARY

[0003] To overcome the deficiencies of the prior art, the present application provides a method and system for searching for flight waypoints of an unmanned aerial vehicle (UAV) in line flight, which can improve the efficiency of planning the flight route of a long linear road UAV. The specific technical solutions are as follows:

[0004] In a first aspect, a method for searching for flight waypoints of an unmanned aerial vehicle (UAV) in line flight is provided. In a first implementation of the first aspect, the method comprises:

[0005] obtaining a sequence of discrete points of a center line of an inspection road and a flight point interval;

[0006] determining a direction vector of a to-be-searched polyline segment based on corresponding endpoint coordinates in the sequence of discrete points of the center line, the to-be-searched polyline segment being a road center line polyline segment where a current flight point is located, and the current flight point being a newly searched flight point;

[0007] determining a candidate flight point coordinate based on the current flight point coordinate, the direction vector, and the flight point interval, and the specific calculation formula being as follows:

[0008] ;

[0009] wherein, is the current flight point coordinate, is the flight point interval, is the direction vector;

[0010] verifying whether the candidate flight point is located on the to-be-searched polyline segment based on the candidate flight point coordinate;

[0011] in response to the candidate flight point being located on the to-be-searched polyline segment, taking the candidate flight point as a new current flight point, and continuing to search for a next flight point based on the new current flight point coordinate;

[0012] in response to the candidate waypoint not being located on the to-be-searched polyline segment, calculating a remaining distance to be moved subsequently after moving along the to-be-searched polyline segment;

[0013] searching a target segment from all the subsequent polyline segments according to the remaining distance;

[0014] determining a new current waypoint coordinate through the start point plane coordinate, the direction vector and the remaining distance of the target segment, and continuing to search a next waypoint according to the new current waypoint coordinate;

[0015] verifying whether the candidate waypoint is located on the to-be-searched polyline segment, comprising:

[0016] a coordinate range determined according to the start point plane coordinate and the end point coordinate corresponding to the to-be-searched polyline segment;

[0017] comparing the candidate waypoint coordinate with the coordinate range;

[0018] in response to the candidate waypoint coordinate not being in the coordinate range, the candidate waypoint not being on the to-be-searched polyline segment;

[0019] in response to the candidate waypoint coordinate being in the coordinate range, performing function fitting according to the start point plane coordinate and the end point coordinate corresponding to the to-be-searched polyline segment, and judging whether the candidate waypoint coordinate satisfies the fitting function;

[0020] in response to the candidate waypoint coordinate satisfying the fitting function, the candidate waypoint being on the to-be-searched polyline segment.

[0021] in combination with the first implementation manner of the first aspect, in the second implementation manner of the first aspect, the method further comprises:

[0022] constructing a local plane coordinate system with the start point of the inspection road as the center, and converting the position coordinates of all end points in the sequence of the center line discrete points to the local plane coordinate system.

[0023] in combination with the first implementation manner of the first aspect, in the third implementation manner of the first aspect, the method further comprises:

[0024] planning an optimal flight height of the inspection according to the device parameters of the inspection unmanned aerial vehicle;

[0025] based on the optimal flight height, combining a set lateral overlap rate, a camera focal length and image parameters, and calculating the waypoint interval distance.

[0026] in combination with the first implementation manner of the first aspect, in the fourth implementation manner of the first aspect, the method further comprises:

[0027] According to the current waypoint coordinate and the end point coordinate of the to-be-searched polyline segment, a straight line distance from a previous waypoint to an end point of the to-be-searched polyline segment is calculated;

[0028] The remaining distance to be moved subsequently is calculated according to the straight line distance and the waypoint interval.

[0029] With reference to the first implementation manner of the first aspect, in a fifth implementation manner of the first aspect, searching for the target line segment in the subsequent polyline segment according to the remaining distance comprises:

[0030] The line segment length corresponding to the subsequent polyline segment is compared with the remaining distance in sequence;

[0031] In response to the line segment length of the subsequent polyline segment exceeding the remaining distance, the polyline segment is taken as the target line segment.

[0032] In response to the line segment lengths of all the subsequent polyline segments being less than the remaining distance, the remaining distance is updated based on the length of a next polyline segment of the to-be-searched polyline segment, and the target line segment is searched again.

[0033] With reference to the first implementation manner of the first aspect, in a sixth implementation manner of the first aspect, the method further comprises:

[0034] A point interval between the current waypoint and the inspection end point is calculated according to the corresponding coordinates, and it is determined whether the point interval is less than the waypoint interval;

[0035] In response to the point interval exceeding the waypoint interval, a next waypoint is searched continuously.

[0036] In response to the point interval being less than the waypoint interval, the waypoint searching is stopped.

[0037] In a second aspect, a method for planning a line-imitating flight route is provided, and in a first implementation manner of the second aspect, the method comprises:

[0038] The line-imitating flight waypoint searching method of any one of the first to sixth implementation manners of the first aspect is adopted to search for a waypoint set corresponding to the inspection road;

[0039] The coordinates of all the waypoints in the waypoint set are converted into longitude and latitude, and the converted waypoint set is yaw-corrected.

[0040] The line-imitating flight route is planned through the corrected waypoint set.

[0041] With reference to the first implementation manner of the second aspect, in a second implementation manner of the second aspect, the yaw correction of the waypoints in the waypoint set comprises:

[0042] Calculate the azimuth angles of the front and rear flight segments of the to-be-corrected waypoint based on the longitude and latitude of the adjacent preceding waypoint and the adjacent following waypoint of the to-be-corrected waypoint;

[0043] Correct the heading angle of the to-be-corrected waypoint according to the average value of the azimuth angles of the front and rear flight segments.

[0044] In a third aspect, a flight path planning system for line-imitating flight is provided, comprising:

[0045] A waypoint searching module configured to search for a set of waypoints corresponding to the inspection road by using the method for searching for waypoints for line-imitating flight of the unmanned aerial vehicle according to any one of the first to sixth possible implementations of the first aspect;

[0046] A waypoint correction module configured to convert the coordinates of all the waypoints in the set of waypoints into longitude and latitude, and correct the set of converted waypoints in yaw;

[0047] A flight path planning module configured to plan a flight path for line-imitating flight through the set of corrected waypoints.

[0048] Beneficial effects: The method for searching for waypoints for line-imitating flight of the unmanned aerial vehicle, the method for planning a flight path and the system can automatically generate inspection waypoints distributed along the center line of the inspection road in sequence through plane geometry calculation according to the sequence of center line discrete points corresponding to the inspection road and the distance between the waypoints adaptively calculated according to the width of the inspection road and the performance parameters of the unmanned aerial vehicle, thereby improving the efficiency of planning a flight path for line-imitating flight inspection of the unmanned aerial vehicle along the long linear road, and enabling the unmanned aerial vehicle to inspect along the center line of the road, avoiding phenomena such as angle deviation between the image and the extension direction of the road, incomplete coverage of the two-way lane, deviation from the inspection target in scenes such as curved roads and branch mouths, etc. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order to more clearly illustrate the specific embodiments of the present application, the drawings required to be used in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0050] Figure 1 A flowchart of the method for searching for waypoints for line-imitating flight of the unmanned aerial vehicle provided by an embodiment of the present application;

[0051] Figure 2 A flowchart of the method for planning a flight path for line-imitating flight provided by an embodiment of the present application. DETAILED DESCRIPTION

[0052] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, but cannot limit the protection scope of the present application.

[0053] As Figure 1 shown in the flow chart of the unmanned aerial vehicle follow-the-line flight waypoint search method, the search method comprises:

[0054] Step 1, obtaining the center line discrete point sequence of the inspection road and the waypoint spacing;

[0055] Step 2, determining the direction vector of the to-be-searched polyline segment according to the corresponding endpoint coordinates in the center line discrete point sequence;

[0056] Step 3, determining the candidate waypoint coordinates based on the current waypoint coordinates, combining the direction vector and the waypoint spacing;

[0057] Step 4, verifying whether the candidate waypoint is located on the to-be-searched polyline segment according to the candidate waypoint coordinates;

[0058] In response to the candidate waypoint being located on the to-be-searched polyline segment, taking the candidate waypoint as the current waypoint, and continuing to search the next waypoint according to the current waypoint coordinates;

[0059] In response to the candidate waypoint not being located on the to-be-searched polyline segment, calculating the remaining distance to be moved along the to-be-searched polyline segment;

[0060] Step 5, searching the target polyline segment from all the subsequent polyline segments according to the remaining distance;

[0061] Step 6, determining the current waypoint coordinates through the start point plane coordinates of the target polyline segment, the direction vector and the remaining distance.

[0062] Specifically, first, the road center line can be extracted from the surveying and mapping data corresponding to the inspection road, the road center line is composed of continuous polyline segments, the endpoint coordinates of each polyline segment can be obtained by discrete point sampling to generate the corresponding center line discrete point sequence, and the waypoint spacing between each waypoint in the follow-the-line inspection flight route corresponding to the inspection road is set. Then, the starting point of the follow-the-line inspection flight route can be set on the road center line, and the starting point is taken as the current waypoint, the polyline segment where the current waypoint is located is determined according to the waypoint coordinates, and the polyline segment is taken as the to-be-searched polyline segment, and the corresponding direction vector is calculated according to the endpoint coordinates of the to-be-searched polyline segment. The specific calculation formula is as follows:

[0063] ;

[0064] Wherein, , are the start point coordinates and the end point coordinates of the to-be-searched polyline segment .

[0065] Then, the coordinates of the candidate waypoint can be determined according to the current waypoint coordinates, the direction vector of the to-be-searched polyline segment and the set waypoint spacing, and the specific calculation formula is as follows:

[0066] ;

[0067] wherein, is the current waypoint coordinate, is the waypoint interval.

[0068] Then, since the candidate waypoint determined according to the above method may exceed the to-be-searched polyline segment, after determining the coordinate of the candidate waypoint, it is still necessary to verify whether the candidate waypoint is on the to-be-searched polyline segment according to the coordinate of the candidate waypoint. If it is on the to-be-searched polyline segment, the candidate waypoint can be included in the waypoint set, and the candidate waypoint is taken as a new current waypoint, and the next waypoint is searched along the road center line according to the above method.

[0069] If it is not on the to-be-searched polyline segment, cross-segment processing needs to be performed. Specifically, first, the straight-line distance from the last waypoint to the end point of the to-be-searched polyline segment can be calculated, and then the remaining distance that needs to be moved after the UAV moves to the end point of the to-be-searched polyline segment is calculated in combination with the set waypoint interval. The specific calculation formula is as follows:

[0070] ;

[0071] ;

[0072] wherein, is the remaining distance, is the straight-line distance from the last waypoint to the end point of the to-be-searched polyline segment, is the end point coordinate of the polyline segment , which is also the start point coordinate of the polyline segment .

[0073] Then, the polyline segment whose segment length exceeds the remaining distance can be searched out as a target segment in the subsequent polyline segment of the to-be-searched polyline segment. Finally, the direction vector corresponding to the target segment can be calculated according to the above calculation method of the direction vector, and the waypoint meeting the waypoint interval can be searched out in the target segment in combination with the start point coordinate of the target segment and the remaining distance. The specific calculation formula is as follows:

[0074] ;

[0075] ;

[0076] wherein, is the start point coordinate of the target segment , is the segment length of the target segment, is the end point coordinate of the target segment, is the direction vector corresponding to the target segment, The searched waypoint on the target line segment can be used as a new current waypoint, and the next waypoint is searched along the center line of the road according to the above method.

[0077] In this way, the simulated-line inspection waypoints of the inspection road can be automatically generated according to the set waypoint interval, thereby improving the simulated-line flight inspection route planning efficiency of the unmanned aerial vehicle for long linear roads.

[0078] In the embodiment, the sequence of discrete points of the center line of the inspection road is obtained, including:

[0079] A local plane coordinate system is constructed with the starting point of the inspection road as the center, and the position coordinates of all end points in the sequence of discrete points of the center line are converted to the local plane coordinate system.

[0080] Specifically, in order to improve the geometric calculation efficiency and accuracy, after obtaining the sequence of discrete points of the center line, the coordinates of each end point in the sequence of discrete points of the center line can be converted to a local plane coordinate system constructed with the starting point of the inspection road as the center, so as to simplify the subsequent waypoint search from spherical calculation to plane calculation. The specific calculation formula is as follows:

[0081] ;

[0082] ;

[0083] wherein, is the radius of the earth, is the coordinate of the end point before conversion, is the coordinate of the starting point, is the coordinate of the end point after conversion, , are the conversion coefficients corresponding to the axis coordinate and the axis coordinate, respectively.

[0084] In the embodiment, the waypoint interval of the inspection road is obtained, including:

[0085] The optimal flight height of the inspection is planned according to the equipment parameters of the inspection unmanned aerial vehicle;

[0086] Based on the optimal flight height, the waypoint interval is calculated in combination with the set lateral overlap rate, camera focal length and image parameters.

[0087] Specifically, the height corresponding to the inspection waypoint will affect the coverage range and spatial resolution of the inspection image. If the waypoint is set manually, it is difficult to balance the spatial resolution and coverage range of the inspection image. If the flight height corresponding to the waypoint is too low, the image coverage range will be insufficient. If it is too high, the ground resolution will decrease, which is difficult to meet the detection requirements of cracks, markings and other details.

[0088] To this end, the corresponding optimal flight height in the inspection process can be calculated in combination with the device parameters of the inspection unmanned aerial vehicle and the width of the inspection road, and the specific calculation formula is as follows:

[0089]

[0090] wherein, is the focal length of the camera of the unmanned aerial vehicle, is the sensor pixel size, is the number of horizontal pixels of the image, is the width of the inspection road.

[0091] Then, based on the optimal flight height, the lateral overlap rate set by the artificial, the camera focal length and the image parameters are combined to adaptively set the flight point spacing, and the specific calculation formula is as follows:

[0092]

[0093] wherein, is the number of longitudinal pixels, is the lateral overlap rate.

[0094] Based on the adaptive calculation of the flight point spacing, the search flight point can be ensured to strictly set the straight line distance between adjacent flight points according to the flight point distance, so as to ensure that the unmanned aerial vehicle can fully cover the inspection road of the flight point area, while avoiding reducing the spatial resolution of the inspection result to meet the detection requirements of cracks, markings and other details.

[0095] In the embodiment, optionally, whether the candidate flight point is located on the to-be-searched polyline segment includes:

[0096] determining a coordinate range according to the start point plane coordinate and the end point coordinate corresponding to the to-be-searched polyline segment;

[0097] comparing the candidate flight point coordinate with the coordinate range;

[0098] in response to the candidate flight point coordinate not being in the coordinate range, the candidate flight point is not on the to-be-searched polyline segment;

[0099] in response to the candidate flight point coordinate being in the coordinate range, performing function fitting according to the start point plane coordinate and the end point coordinate corresponding to the to-be-searched polyline segment, and determining whether the candidate flight point coordinate satisfies the fitting function;

[0100] in response to the candidate flight point coordinate satisfying the fitting function, the candidate flight point is on the to-be-searched polyline segment.

[0101] ​​Specifically, the coordinates of the searched candidate waypoints can be compared with the following verification conditions. If the candidate waypoint coordinates meet all of the following verification conditions, it indicates that the candidate waypoint lies on the polyline segment to be searched. The verification conditions are as follows:

[0102] ;

[0103] The verification conditions mentioned above can be obtained by solving for the starting and ending coordinates of the line segment to be searched. and , and These are the coefficients corresponding to the fitted function. These are the coordinates of the candidate waypoints.

[0104] In this embodiment, optionally, it also includes:

[0105] Calculate the distance between the current waypoint and the inspection endpoint based on the corresponding coordinates, and determine whether the distance between the points is less than the waypoint distance.

[0106] If the point spacing exceeds the waypoint spacing, continue searching for the next waypoint;

[0107] In response to the point spacing being less than the waypoint spacing, the waypoint search is stopped.

[0108] Specifically, after finding a new waypoint, before searching for the next waypoint, it is necessary to determine whether the distance between the current waypoint and the endpoint of the simulated inspection route is sufficient for a waypoint search. Specifically, the distance between the current waypoint and the inspection endpoint can be calculated based on their coordinates. The specific calculation formula is as follows:

[0109] ;

[0110] in, The coordinates of the inspection endpoint The distance between dots is the distance between dots.

[0111] Then, the calculated point spacing is compared with the waypoint spacing. If the point spacing exceeds the waypoint spacing, the search for the next waypoint can continue. Otherwise, the current waypoint is the final waypoint, and the waypoint search stops.

[0112] like Figure 2 The flowchart shown illustrates a linear flight path planning method, which includes:

[0113] Step S1: Using the above-mentioned UAV waypoint search method, search for the set of waypoints corresponding to the inspection road.

[0114] Step S2, converting the coordinates of all the waypoints in the set of waypoints into latitude and longitude, and performing yaw correction on the converted set of waypoints;

[0115] Step S3, planning a line-simulating flight route through the corrected set of waypoints.

[0116] Specifically, first, the search method described above can be used to automatically search for each waypoint of the inspection route along the road centerline, generating a corresponding set of waypoints. Then, since the set of waypoints is constructed based on a local plane coordinate system, the coordinates of all the waypoints in the set of waypoints can be converted into latitude and longitude, and the converted waypoints can be yaw-corrected to avoid angular deviation of the inspection image from the extension direction of the road. The specific latitude and longitude conversion formula is as follows:

[0117]

[0118] wherein, is the coordinate of the waypoint. is the latitude and longitude of the waypoint.

[0119] Finally, the line-simulating flight route of the inspection UAV can be automatically generated according to the corrected set of waypoints.

[0120] In this embodiment, optionally, the waypoints in the set of waypoints are yaw-corrected, including:

[0121] Based on the latitude and longitude of the adjacent preceding waypoint and the adjacent following waypoint of the waypoint to be corrected, the azimuth angles of the front and rear flight segments of the waypoint to be corrected are calculated.

[0122] The heading angle of the waypoint to be corrected is corrected according to the average of the azimuth angles of the front and rear flight segments.

[0123] Specifically, first, the longitude difference can be calculated according to the latitude and longitude of the adjacent preceding waypoint and the adjacent following waypoint of the waypoint to be corrected, and the specific calculation formula is as follows:

[0124]

[0125] Then, the azimuth angle component is calculated based on the calculated longitude difference, and the specific calculation formula is as follows:

[0126]

[0127]

[0128] wherein, is the latitude of the waypoint to be corrected, , are the latitudes of the preceding waypoint and the following waypoint, , ​​​​respectively are the longitude difference between the to-be-corrected waypoint and the previous waypoint and the after waypoint. , respectively are the azimuth component between the to-be-corrected waypoint and the previous waypoint and the after waypoint.

[0129] Then, the azimuth of the to-be-corrected waypoint can be calculated according to the calculated azimuth component , and the specific calculation formula is as follows:

[0130] ;

[0131] wherein, , respectively are the front segment azimuth and the after segment azimuth. Finally, the heading angle of the waypoint can be corrected according to the azimuth of the to-be-corrected waypoint , and the specific correction calculation formula is as follows:

[0132] .

[0133] wherein, is the corrected flight yaw angle.

[0134] A flight path planning system for line following flight, comprising:

[0135] a waypoint search module configured to search out a set of waypoints corresponding to the inspection road according to the above-mentioned method for searching out waypoints for line following flight of a UAV;

[0136] a waypoint correction module configured to convert the coordinates of all waypoints in the set of waypoints into latitude and longitude, and to perform yaw correction on the converted set of waypoints;

[0137] a flight path planning module configured to plan a flight path for line following flight from the corrected set of waypoints.

[0138] Specifically, the planning system comprises a waypoint search module, a waypoint correction module and a flight path planning module. The waypoint search module can automatically search out each waypoint of the inspection flight path along the center line of the road and generate a corresponding set of waypoints using the above-mentioned search method. The waypoint correction module can convert the coordinates of all waypoints in the set of waypoints into latitude and longitude, and perform yaw correction on the converted waypoints to avoid angular deviation between the inspection image and the extension direction of the road. The flight path planning module can automatically generate a flight path for line following flight of the inspection UAV according to the corrected set of waypoints, thereby achieving automatic planning of the flight path for line following flight of the inspection UAV and improving the planning efficiency of the flight path for line following flight of the UAV for long linear roads.

[0139] The above examples are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some or all of the technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A method for searching waypoints during UAV line-following flight, characterized in that, include: Obtain the discrete point sequence of the centerline of the inspected road and the waypoint spacing; Based on the corresponding endpoint coordinates in the discrete point sequence of the centerline, determine the direction vector of the polyline segment to be searched. The polyline segment to be searched is the road centerline polyline segment where the current waypoint is located, and the current waypoint is the latest waypoint found. Based on the current waypoint coordinates, combined with the direction vector and waypoint spacing, the coordinates of candidate waypoints are determined. The specific calculation formula is as follows: ； in, The coordinates of the current waypoint The distance between waypoints, It is the direction vector; Verify whether the candidate waypoint is located on the polyline segment to be searched based on the candidate waypoint coordinates; In response to a candidate waypoint being located on the polyline segment to be searched, the candidate waypoint is used as the new current waypoint, and the search for the next waypoint continues based on the coordinates of the new current waypoint; In response to the fact that the candidate waypoint is not located on the polyline segment to be searched, calculate the remaining distance to be moved after moving along the polyline segment to be searched; Based on the remaining distance, search for the target line segment in all subsequent polyline segments; The new waypoint coordinates are determined by the starting plane coordinates, direction vector and remaining distance of the target line segment, and the search for the next waypoint continues based on the new current waypoint coordinates; Verify whether the candidate waypoint lies on the polyline segment to be searched, including: The coordinate range is determined based on the starting plane coordinates and ending plane coordinates of the polyline segment to be searched; Compare the candidate waypoint coordinates with the coordinate range; If the candidate waypoint coordinates are not within the coordinate range, the candidate waypoint is not on the polyline segment to be searched. In response to the candidate waypoint coordinates being within the coordinate range, a function is fitted based on the starting plane coordinates and ending plane coordinates of the polyline segment to be searched, and it is determined whether the candidate waypoint coordinates satisfy the fitting function. If the coordinates of the candidate waypoints satisfy the fitted function, then the waypoint is selected on the polyline segment to be searched.

2. The method for searching waypoints by UAV line-following flight according to claim 1, characterized in that, Obtain the discrete point sequence of the centerline of the inspected road, including: A local plane coordinate system is constructed with the starting point of the inspection road as the center, and the position coordinates of all endpoints in the discrete point sequence of the center line are transformed to the local plane coordinate system.

3. The method for searching waypoints by UAV line-following flight according to claim 1, characterized in that, Obtain the waypoint spacing of the inspected road, including: The optimal flight altitude for inspection is planned based on the equipment parameters of the inspection drone; Based on the optimal flight altitude, and combined with the set lateral overlap rate, camera focal length, and image parameters, the waypoint spacing is calculated.

4. The method for searching waypoints by UAV line-following flight according to claim 1, characterized in that, Calculate the remaining distance that needs to be moved, including: Based on the current waypoint coordinates and the endpoint coordinates of the polyline segment to be searched, calculate the straight-line distance from the previous waypoint to the endpoint of the polyline segment to be searched; The remaining distance to be traveled is calculated using the straight-line distance and waypoint spacing.

5. The method for searching waypoints by UAV line-following flight according to claim 1, characterized in that, Based on the remaining distance, the target line segment is searched in the subsequent polyline segments, including: The lengths of the subsequent line segments are compared with the remaining distance in turn; If the length of a subsequent polyline segment exceeds the remaining distance, then that polyline segment is taken as the target segment. In response to the fact that the length of all subsequent polyline segments is less than the remaining distance, the remaining distance is updated based on the length of the next polyline segment of the polyline segment to be searched, and the target segment is searched again.

6. The method for searching waypoints by UAV line-following flight according to claim 1, characterized in that, Also includes: Calculate the distance between the current waypoint and the inspection endpoint based on the corresponding coordinates, and determine whether the distance between the points is less than the waypoint distance. If the point spacing exceeds the waypoint spacing, continue searching for the next waypoint; In response to the point spacing being less than the waypoint spacing, the waypoint search is stopped.

7. A method for planning flight paths using linear flight paths, characterized in that, include: Using the UAV waypoint search method described in any one of claims 1-6, the set of waypoints corresponding to the inspection road is searched. Convert the coordinates of all waypoints in the waypoint set to latitude and longitude, and perform yaw correction on the converted waypoint set; A simulated flight route was planned using the revised waypoint set.

8. The method for planning flight paths based on linear flight according to claim 7, characterized in that, Yaw corrections are performed on waypoints in the waypoint set, including: Based on the latitude and longitude of the preceding and following waypoints adjacent to the waypoint to be corrected, calculate the azimuth of the preceding and following segments of the waypoint to be corrected. The heading angle of the waypoint to be corrected is adjusted based on the average azimuth angle of the preceding and following segments.

9. A line-following flight path planning system, characterized in that, include: The waypoint search module is configured to use the UAV waypoint search method as described in any one of claims 1-6 to search for the set of waypoints corresponding to the inspection road. The waypoint correction module is configured to convert the coordinates of all waypoints in the waypoint set into latitude and longitude, and to perform yaw correction on the converted waypoint set. The route planning module is configured to plan a mimicry flight route using the modified waypoint set.

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