CN116520881A - Unmanned plane continuous tower foundation three-dimensional inspection path planning method based on laser point cloud - Google Patents
Unmanned plane continuous tower foundation three-dimensional inspection path planning method based on laser point cloud Download PDFInfo
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Abstract
The invention relates to a laser point cloud-based unmanned aerial vehicle continuous tower foundation three-dimensional inspection path planning method, which comprises the following steps: step 1: acquiring laser point cloud data of a power transmission line, and extracting plane position information and elevation information of a measured point to serve as information to be processed; step 2: downsampling the information to be processed to obtain information to be filtered; step 3: carrying out elevation filtering on the information to be filtered by utilizing an elevation threshold value, and reserving plane position information and elevation information of a measured point, of which the elevation information is higher than the elevation threshold value, as information to be fitted; step 4: performing piecewise fitting by utilizing information to be fitted to obtain a multi-piecewise linear equation of the power transmission wire based on the geodetic coordinates; step 5: extracting the lightning conductor coordinates and obtaining the continuous track point coordinates by utilizing a multi-piecewise linear equation: step 6: acquiring position information of a patrol track point of the unmanned aerial vehicle; step 7: and obtaining the three-dimensional inspection path of the unmanned aerial vehicle. The unmanned aerial vehicle inspection path planning method and the unmanned aerial vehicle inspection path planning system can rapidly conduct unmanned aerial vehicle inspection path planning, and are ideal in effect.
Description
Technical Field
The invention relates to the technical field of power inspection, in particular to an unmanned aerial vehicle continuous tower foundation three-dimensional inspection path planning method based on laser point cloud.
Background
The unmanned aerial vehicle application is a core carrier for intelligent replacement of power inspection operation. The current working mode of unmanned aerial vehicle autonomous patrol is that the unmanned aerial vehicle is manually controlled to completely patrol the line channel and the pole tower, laser point cloud data are collected and three-dimensional modeling is carried out, and a track is planned for the unmanned aerial vehicle, so that unmanned aerial vehicle autonomous patrol is realized. The premise of the track planning is to extract coordinates of a wire and a pole tower from laser point cloud data of a power transmission line. The lightning conductor and the power transmission conductor are positioned in the same two-dimensional plane, only the difference in elevation exists, and the conductors with different voltage levels have definite distance requirements in the vertical direction. Based on the extraction of lightning conductor coordinates, can make things convenient for unmanned aerial vehicle to patrol the lightning conductor defect, still can down-regulate unmanned aerial vehicle flight path's elevation to patrol the transmission line below the lightning conductor. In the prior art, various clustering, searching and fitting algorithms are adopted to extract transmission wires in restored point cloud data, the point cloud data volume in the researches is only millions, and when the point cloud data volume is larger than the huge point cloud data volume, such as more than 3 hundred million data, the running of the existing algorithm takes a lot of time, and the coordinates of the wires cannot be obtained quickly, so that the unmanned aerial vehicle inspection path planning efficiency is affected.
Disclosure of Invention
The invention aims to provide a method capable of rapidly extracting the coordinates of lightning wires in a power transmission wire from huge amount of point cloud data so as to efficiently carry out unmanned aerial vehicle inspection path planning.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the unmanned aerial vehicle continuous tower foundation three-dimensional inspection path planning method based on the laser point cloud is used for extracting the coordinates of a lightning wire from laser point cloud data of a power transmission line and planning a three-dimensional inspection path of an unmanned aerial vehicle, and comprises the following steps of:
step 1: acquiring laser point cloud data of the power transmission line, extracting plane position information and elevation information of each measured point from the laser point cloud data as information to be processed, and dividing the information to be processed into a plurality of groups according to a plurality of wire segments obtained by dividing a power transmission wire in the power transmission line;
step 2: respectively carrying out downsampling treatment on each group of information to be processed to obtain a plurality of groups of corresponding information to be filtered;
step 3: respectively carrying out elevation filtering treatment on each group of information to be filtered by using a preset elevation threshold value, and reserving plane position information and elevation information of the measured points with the elevation information higher than the elevation threshold value as information to be fitted;
step 4: performing piecewise fitting by utilizing the information to be fitted to obtain a multi-piecewise linear equation of the power transmission wire in an x-o-y plane based on geodetic coordinates;
step 5: the following steps are performed for each straight line segment of the multi-piecewise linear equation:
step 5-1: acquiring coordinates of each measured point on the electric transmission line corresponding to the straight line segment in the x-o-y plane as geodetic coordinates under an original coordinate system;
step 5-2: rotating the straight line segment in the x-o-y plane to be parallel to the x axis in the x-o-y plane, and converting to obtain the coordinates of each measured point on the electric transmission line corresponding to the straight line segment in the x-o-y plane as the coordinates in a new coordinate system;
step 5-3: setting a unit length, and equally segmenting the power transmission wires along the x-axis direction, wherein the length of each segment of power transmission wire is equal to the unit length;
step 5-4: setting matrices XB, YB and ZB, wherein the lengths of the matrices XB, YB and ZB are the number of segments for averagely segmenting the power transmission wire along the x-axis direction, the elements in the matrices XB correspond to the x-coordinate of the measured point on each segment of the power transmission wire, the elements in the matrices YB correspond to the y-coordinate of the measured point on each segment of the power transmission wire, the elements in the matrices ZB correspond to the z-coordinate of the measured point on each segment of the power transmission wire, and the initial values of the matrices XB, YB and ZB are all 0;
step 5-5: traversing each section of the power transmission wire, and for any section of the power transmission wire, if a measured point on the power transmission wire meets the condition that an x coordinate is in a corresponding segmented interval and a z coordinate is larger than a value of a corresponding element in the matrix ZB, updating the corresponding element in the matrix XB, the matrix YB and the matrix ZB by using the coordinate of the current measured point under the new coordinate system;
step 5-6: removing zero values in the matrix XB, the matrix YB and the matrix ZB;
step 5-7: extracting point cloud data of the lightning conductor under the new coordinate system based on the matrix XB, the matrix YB and the matrix ZB;
step 5-8: based on the point cloud data of the lightning conductor under the new coordinate system, shifting each point cloud data by a meter along the positive direction of the y axis and by d meters along the negative direction of the z axis to obtain the tracking wire track point coordinate of the unmanned aerial vehicle under the new coordinate system;
step 5-9: searching point cloud data of the lightning conductor in a distance of b meters from the center of each tower along the transmission conductor based on the point cloud data of the lightning conductor in the new coordinate system, and shifting the point cloud data by c meters along the positive direction of the z axis to obtain the tower and conductor connection track point coordinates of the unmanned aerial vehicle in the new coordinate system;
step 5-10: based on the tracking guide line track point coordinates of the unmanned aerial vehicle under the new coordinate system and the tower and guide line connection track point coordinates of the unmanned aerial vehicle under the new coordinate system, interpolating at the discontinuous positions of the track points to obtain the coordinates of continuous track points under the new coordinate system;
step 5-11: converting the coordinates of the continuous track points in the new coordinate system into geodetic coordinates of the continuous track points in the original coordinate system;
step 6: correspondingly converting the x coordinate and the y coordinate of the continuous track point in the geodetic coordinates under the original coordinate system into the longitude and latitude coordinates of the continuous track point under the original coordinate system, thereby obtaining the position information of the unmanned aerial vehicle inspection track point;
step 7: and obtaining a three-dimensional inspection path of the unmanned aerial vehicle based on the position information of the inspection track point of the unmanned aerial vehicle.
In the step 1, plane position information and elevation information of the measured point are extracted through a lasty library of python language.
In the step 1, the power transmission wire is divided into a plurality of wire segments according to the tower position and the number of the laser point cloud data, so that the number of the laser point cloud data corresponding to each wire segment is four tens of millions to eight tens of millions.
In the step 2, a function in an open3D library is adopted to carry out downsampling processing on the data to be processed after format conversion.
In the step 2, the information to be processed is subjected to downsampling processing by adopting uniform downsampling, voxel downsampling or curvature downsampling.
In the step 3, the elevation threshold value corresponding to each wire segment is the sum of the elevation mean value of the wire segment and a preset value.
And for the power transmission line positioned in a mountain area or a rugged terrain area, in the step 3, after the information to be filtered is ordered based on an x-axis direction coordinate or a y-axis direction, dividing the information into a plurality of small range areas, and carrying out elevation filtering processing in each small range area.
In the step 4, when the segment fitting is performed, if a segment of the power transmission line cannot form a function related to the y-axis direction in the x-axis direction, converting the x-axis direction and the y-axis direction for fitting, and performing inverse function transformation on the obtained function to obtain a corresponding linear equation; if one section of the power transmission line cannot form a function in the x-axis direction and the y-axis direction, the power transmission line is segmented again and then segmented fitting is carried out.
In the step 5, the piecewise point of the multi-piecewise linear equation is a tower position.
In the step 5-1, the density of the measured point on the power transmission wire is obtained by using a density function in a seaborn library, and then the position of the tower is judged by using the density of the measured point on the power transmission wire.
In the steps 5-8, the value of a is 2, the value of d is determined by the voltage level of the power transmission line, and the value of d is 2, 3.5, 6 or 10.
In the steps 5-9, the value of b is 10, and the value of c is 2.
In the steps 5-10, linear interpolation is performed at the discontinuous position of the navigation points.
In the step 6, the x coordinate and the y coordinate in the geodetic coordinates of the continuous track points in the original coordinate system are correspondingly converted into the longitude and latitude coordinates of the continuous track points in the original coordinate system through a plane four-parameter model.
In the step 7, the position information of the unmanned aerial vehicle inspection track point is input into an unmanned aerial vehicle terminal for autonomous flight.
In the step 5-2, the rotation angle of the straight line segment is equal to alpha based on the slope tan alpha of the straight line segment, and thenCalculating the coordinates of each measured point on the electric transmission line corresponding to the straight line segment under the new coordinate system, wherein ∈>Has the value of-alpha, X 1 、Y 1 Is the x coordinate and y coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the original coordinate system, < ->Is the x coordinate and the y coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the new coordinate system.
In the steps 5-11, use is made ofCalculating the geodetic coordinates of the successive track points in said original coordinate system, wherein +.>Has the value alpha, X 2 、Y 2 、Z 2 Is the x-coordinate, y-coordinate, z-coordinate of the successive track points in said original coordinate system,/-coordinate>Is the x-coordinate, y-coordinate, z-coordinate of the successive track points in the new coordinate system.
In the step 6, use is made ofCalculating longitude and latitude coordinates of continuous track points in the original coordinate system, wherein X 2 、Y 2 Is the X coordinate, the y coordinate and the X coordinate of the continuous track point in the geodetic coordinates under the original coordinate system 3 、Y 3 Is the longitude and latitude coordinates of the continuous track point under the original coordinate system, delta X 0 、ΔY 0 For translation parameters, ε is the rotation parameter and m is the scale parameter.
The translation parameter, the rotation parameter and the scale parameter are obtained through calculation of two pairs of control points, and the coordinates of each pair of control points in a geodetic coordinate system and the coordinates of each pair of control points in a longitude and latitude coordinate system are known.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages: the invention can rapidly position the lightning conductor in the transmission wire, thereby rapidly realizing the planning of the unmanned aerial vehicle inspection path and having ideal effect.
Drawings
Fig. 1 is a flow chart of a laser point cloud-based unmanned aerial vehicle continuous tower base three-dimensional inspection path planning method.
Fig. 2 is a schematic diagram of uniform downsampling.
Fig. 3 is a schematic diagram of voxel downsampling.
Fig. 4 is a schematic diagram of curvature downsampling.
Fig. 5 is a schematic diagram of elevation filtering.
Fig. 6 is a three-dimensional view of a transmission line without a tower.
Fig. 7 is a two-dimensional projection of a transmission line without a tower in the x-o-y plane.
Fig. 8 is a two-dimensional projection view of a transmission line without a tower in an x-o-y plane after rotation.
Fig. 9 is a two-dimensional projection view of a transmission line without a tower in an x-o-z plane after rotation.
Fig. 10 is a schematic diagram of a transmission line including a tower.
FIG. 11 is a schematic diagram of finding a tower location using a density function.
Detailed Description
The invention will be further described with reference to examples of embodiments shown in the drawings.
Embodiment one: the transmission line is composed of a plurality of towers and transmission lines erected on the towers, and generally, two sets of transmission lines of left and right loops are erected on two sides of the towers respectively, and each set of transmission lines of the loops comprises a lightning conductor positioned at the uppermost part and a plurality of return transmission lines below the lightning conductor. According to different voltage levels of the power transmission lines, the distances between the power transmission wires in the vertical direction are different. Typically, about 2.5m below the lightning conductor is the uppermost power transmission conductor, the vertical distance of the 35kV power transmission conductor is about 2 meters, the vertical distance of the 110kV power transmission conductor is about 3.5 meters, the vertical distance of the 220kV power transmission conductor is about 6 meters, and the vertical distance of the 500kV power transmission conductor is about 10 meters.
As shown in fig. 1, the laser point cloud-based unmanned aerial vehicle continuous tower base three-dimensional inspection path planning method for extracting the coordinates of a lightning conductor from laser point cloud data of a power transmission line and planning a three-dimensional inspection path of an unmanned aerial vehicle comprises the following steps:
step 1: and acquiring laser point cloud data of the power transmission line, extracting plane position information and elevation information of each measured point from the laser point cloud data as information to be processed, and dividing the information to be processed into a plurality of groups according to a plurality of wire segments obtained by dividing the power transmission wires in the power transmission line.
Laser point cloud data is collected by radar. When the laser point cloud data of the transmission line are collected, the unmanned aerial vehicle loads the radar, flies right above the transmission line and the pole tower, adopts the Time of Flight (TOF) technology, ensures that the radar measurement accuracy can not change along with the distance change, and under the condition of a long-distance object, the measurement accuracy is still accurate and stable. The flying height of the unmanned aerial vehicle is known, the elevation of the measured point can be obtained through conversion, and the position of the transmission wire can be obtained through a subsequent algorithm flow.
The data format of the laser point cloud data is las. The point cloud information includes: the plane position and elevation of the measured point, RGB (red, green and blue) color information, reflection intensity and the like. And extracting plane position information and elevation information of the measured point through a lasty library of python language for research. Elevation is the altitude in meters.
The geodetic coordinate system is a right-hand 3D coordinate centered on the earth and fixed to the earth, consisting of 3 orthogonal axes, the x-axis and y-axis lying in the equatorial plane, and the z-axis being parallel to the average earth axis of rotation and pointing toward the north pole. By python programming, all three-dimensional points in laser point cloud data are projected to a two-dimensional plane, and a circuit diagram is in a strip shape and is consistent with a circuit distribution trend obtained through longitude and latitude coordinates of a pole tower.
Because of the huge data volume of laser point cloud data, for example, the data size of one transmission line is about 10g,3 billion measured points. A computer with a general memory of 8G cannot process more than 3 million data at a time, so that a power transmission wire is divided into a plurality of wire segments according to the position of a pole tower and the number of laser point cloud data, and the number of the laser point cloud data corresponding to each wire segment is four tens of millions to eight tens of millions. For example, the power transmission line is divided into 5 wire segments, each wire segment has 4000 to 8000 ten thousand points, and then the subsequent downsampling process is performed.
Step 2: and respectively carrying out downsampling treatment on each group of information to be treated to obtain a plurality of groups of corresponding information to be filtered.
Firstly, converting the data in the las format into the pcd format, and then adopting a function in an open3D library to carry out downsampling processing on the data to be processed after format conversion. Since the power transmission line is divided into a plurality of line segments, downsampling processing is performed on the information to be processed corresponding to each line segment.
The downsampling method generally comprises uniform downsampling, voxel downsampling and curvature downsampling, so that the information to be processed is downsampled by adopting the uniform downsampling, the voxel downsampling or the curvature downsampling. The three are distinguished as follows:
(1) As shown in FIG. 2, there are various ways to uniformly downsample, in which the sampling of the farthest point is simpler, a seed point is first selected, and an interior point set is set, and a point farthest from the interior point is found out from the set of non-interior points in the point cloud each time. The sampling point cloud in the mode is uniformly distributed, but the algorithm complexity is high and the efficiency is low.
(2) As shown in fig. 3, voxel downsampling is to voxel a three-dimensional space and then sample a point within each voxel, usually the center point or the point closest to the center is chosen as the sampling point. The sampling efficiency is very high in the mode, the sampling points are distributed uniformly, the distance between the points can be controlled by the voxel size, and the number of the sampling points cannot be controlled accurately.
(3) As shown in fig. 4, curvature downsampling is where the greater the curvature of the point cloud, the more points are sampled. Firstly, calculating the neighborhood of each point, and then calculating the normal angle value from the point to the neighborhood point, wherein the larger the curvature is, the larger the angle value is; then setting an angle threshold, setting 30 degrees herein, wherein points with neighborhood included angle values larger than the threshold are regarded as areas with obvious characteristics, and the rest are unobvious areas; and finally uniformly sampling the characteristic obvious area and the characteristic unobvious area, wherein the sampling number is S (1-U), S is U, S is the target sampling number, and U is the sampling uniformity. The sampling points in the mode are distributed uniformly locally, and the sampling result has stronger noise immunity due to the division of the geometric characteristic region.
The advantages and disadvantages of the three are as follows:
(1) In time, uniform downsampling and voxel downsampling are shortest in time, and curvature downsampling is far more than the former two. Taking a certain section of line containing 8700 ten thousand point clouds as an example, the time for voxel downsampling is about 8s, the time for uniform downsampling is about 5s, and the time for curvature downsampling is about 2.2 hours, because the curvature downsampling needs to extract points to calculate the included angle between the normal vector and the neighborhood fitting plane, classify the included angle value, and finally sample according to the weight according to the classification result.
(2) In effect, the voxel downsampling results in a minimum number of points, the remaining two depending on parameters. Taking a certain section of line containing 8700 ten thousand point clouds as an example, setting the voxel size to be 5 by voxel downsampling to obtain about 5 ten thousand points; sampling every 100 points to obtain about 87 ten thousand points; the curvature downsampling sets 50 points in the neighborhood, the angle threshold is 30 degrees, one point is sampled every 100 points in the feature obvious region, one point is sampled every 200 points in the feature unobvious region, and finally about 60 ten thousand points are obtained.
It can be seen that the number of points obtained by uniform downsampling and curvature downsampling is relatively large, the features of the tower, the wires and the ground can be kept relatively completely, and the curvature downsampling is more advantageous in reflecting local features. The points obtained by voxel downsampling are sparse, the tower point cloud can be hardly reserved, the ground point cloud is greatly reduced, but the sparse wire point cloud still can well reflect the plane distribution characteristics of wires. The voxel downsampling is the best choice considering both the time cost and the sampling effect.
Step 3: and respectively carrying out elevation filtering treatment on each group of information to be filtered by using a preset elevation threshold value, and reserving plane position information and elevation information of a measured point with the elevation information higher than the elevation threshold value as information to be fitted.
The corresponding elevation threshold value of each wire segment is the sum of the elevation mean value of the wire segments and a preset value. For example, according to the operation regulations of overhead transmission lines, the shortest distance between 220kV transmission lines and the ground is 7.5m, the top of a tower is generally 30m higher than the ground, and meanwhile, the elevation threshold value is set to be the average value of the elevation of a section of line segment plus 20m in consideration of the fact that few buildings with elevations near the section of transmission line are similar to the buildings and the transmission line is located in a plain area. As shown in figure 5, all ground points can be filtered through elevation filtering, and lightning wires and two or three wires are reserved without affecting the construction of a plane equation. The extremely discrete points may be airborne flying objects such as birds.
The elevation filtering scheme is suitable for plain areas, and in the step 3, the information to be filtered is divided into a plurality of small-range areas after being ordered based on the x-axis direction coordinate or the y-axis direction, and elevation filtering processing is carried out in each small-range area.
Step 4: and performing piecewise fitting by utilizing the information to be fitted to obtain a multi-piecewise linear equation of the power transmission wire based on the geodetic coordinates, wherein the multi-piecewise linear equation is a linear equation of the power transmission wire on an x-o-y plane.
After the elevation filtering treatment, only the point cloud of the power transmission wire and part of the point cloud of the pole tower are remained, the projection is a segmented straight line on a two-dimensional plane, and then a linear equation of the power transmission wire under a geodetic coordinate system is obtained through multi-segment linear fitting. The multi-piecewise linear equation is as follows:
the precondition for multi-segment fitting is that y is a function of x. If a section of power transmission line cannot form a function related to the x-axis direction in the y-axis direction, converting the x-axis direction and the y-axis direction for fitting, and performing inverse function transformation on the obtained function to obtain a corresponding linear equation of a consistent variable; if a section of power transmission line cannot form a function in the x-axis direction and the y-axis direction, the section fitting is performed after the sections are re-segmented.
Step 5: the piecewise points of the multi-piecewise linear equation are tower positions, and the following steps are respectively executed for each straight line segment of the multi-piecewise linear equation to extract the lightning conductor coordinates:
step 5-1: and acquiring coordinates of each measured point on the electric transmission line corresponding to the straight line segment in the x-o-y plane as the geodetic coordinates under the original coordinate system. Coordinates of the measured point in the x-o-y plane are obtained from plane position information of the measured point.
Step 5-2: and rotating the straight line segment in the x-o-y plane to enable the straight line segment to be parallel to the x axis in the x-o-y plane, and converting to obtain the coordinates of each measured point on the power transmission wire corresponding to the straight line segment in the x-o-y plane as the coordinates under a new coordinate system.
Specifically, the slope tanα of each straight line segment can be obtained. The piecewise point coordinates of the multi-piecewise linear equation and the slope of each straight line segment can be derived separately using the following functions:
break=mypwlf. Fit (value), where value represents the number of fragments
slopes=myPWLF.calc_slopes()
If no tower exists in the straight line segment, the three-dimensional diagram and the two-dimensional projection of the transmission line in the x-o-y plane are respectively shown in figures 6 and 7. Based on the slope tan alpha of the straight line segment, the rotation angle of the straight line segment is equal to alpha, so that the lead is parallel to the x axis, as shown in figure 8, and thenCalculating the new measured points on the electric transmission line corresponding to the straight line segmentCoordinates in a coordinate system, wherein +.>The value of (a) is-alpha, because the rotation matrix takes the anticlockwise positive direction, alpha is the angle between the lead and the X-axis, X 1 、Y 1 Is the x coordinate and y coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the original coordinate system, ">The x coordinate and the y coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the new coordinate system. The elevation (z coordinate) of each point cloud is unchanged by plane rotation. After plane rotation, the projection of the transmission line in the x-o-z plane is shown in figure 9, the distance between the lightning conductor and the wires of several loops below the lightning conductor is obvious, and the corresponding wires of the left loop and the right loop almost coincide. Since the lightning conductor is located at the uppermost position, the coordinates of the lightning conductor can be continuously extracted.
Step 5-3: setting a unit length, and equally segmenting the power transmission wires along the x-axis direction, wherein the length of each segment of power transmission wire is equal to the unit length. Too small a unit length can generate more discrete point clouds of the lower wires, and too large a unit length can discard many lightning conductor corona, so that reasonable selection is needed.
Step 5-4: the matrices XB, YB, ZB are set. The lengths of the matrix XB, the matrix YB and the matrix ZB are the number of segments for averagely segmenting the transmission conductor along the x-axis direction, the elements in the matrix XB correspond to the x coordinates of the measured points on each segment of transmission conductor, the elements in the matrix YB correspond to the y coordinates of the measured points on each segment of transmission conductor, the elements in the matrix ZB correspond to the z coordinates of the measured points on each segment of transmission conductor, and the initial values of the matrix XB, the matrix YB and the matrix ZB are all 0.
Step 5-5: and traversing each section of power transmission wire, namely traversing each x section of the wire after the wire is segmented, and updating corresponding elements in the matrix XB, the matrix YB and the matrix ZB by using the coordinates of the current measured point under a new coordinate system if the measured point on the power transmission wire meets that the x coordinate is in the corresponding segmented section and the z coordinate is larger than the value of the corresponding element in the matrix ZB for any section of power transmission wire. The z-coordinate of the measured point is obtained from its elevation information. So that the finally obtained matrixes XB, YB and ZB correspond to the information containing the lightning conductor.
Step 5-6: zero values in the matrices XB, YB, ZB are removed because there may be no point cloud within the pole individual x-section.
Step 5-7: and extracting point cloud data of the lightning conductor under a new coordinate system based on the matrix XB, the matrix YB and the matrix ZB.
Step 5-8: based on the point cloud data of the lightning conductor under the new coordinate system, each point cloud data is offset by a meter along the positive direction of the y axis and offset by d meter along the negative direction of the z axis, namely, each element in the matrix YB is increased by a, each element in the matrix ZB is reduced by d, and each element in the matrix XB is kept unchanged, so that the tracking wire track point coordinate of the unmanned aerial vehicle under the new coordinate system is obtained.
In this step, the value of a is 2, the value of d is determined by the voltage class of the transmission line, i.e. for a 35kV transmission line, the value of d is 2, for a 110kV transmission line, the value of d is 3.5, for a 220kV transmission line, the value of d is 6, and for a 500kV transmission line, the value of d is 10.
Step 5-9: and searching point cloud data of b meters along the transmission line from the center of each tower based on the point cloud data of the lightning conductor in the new coordinate system, and shifting the point cloud data by c meters along the positive direction of the z axis to obtain the coordinates of the connection track points of the towers and the lines of the unmanned aerial vehicle in the new coordinate system.
In the step, the value of b is 10, the value of c is 2, namely, each element in the matrix ZB is increased by 2 at the position of each tower which is 10 meters away from the center of the tower along the direction of the transmission line, and each element in the matrix XB and the matrix YB is unchanged, so that a tower connection track point where the towers are connected with the transmission line is obtained.
Tracking the coordinates of the guide track points and the coordinates of the guide track points connected with the towers and the guide tracks together form the track points for inspection of the unmanned aerial vehicle.
Step 5-10: and carrying out linear interpolation at the discontinuous positions of the track points based on the track wire track point coordinates of the unmanned aerial vehicle under the new coordinate system and the tower and wire joint track point coordinates of the unmanned aerial vehicle under the new coordinate system to obtain the coordinates of the continuous track points under the new coordinate system.
Step 5-11: converting the coordinates of the continuous track points in the new coordinate system into the geodetic coordinates of the continuous track points in the original coordinate system;
in this step, use is made ofCalculating the geodetic coordinates of the successive track points in the original coordinate system, wherein +.>Has the value alpha, X 2 、Y 2 、Z 2 Is the x coordinate, y coordinate, z coordinate of the continuous track point in the original coordinate system,/->Is the x coordinate, y coordinate and z coordinate of the continuous track point in the new coordinate system.
Step 6: and correspondingly converting the x coordinate and the y coordinate of the continuous track point in the geodetic coordinate under the original coordinate system into the longitude and latitude coordinate of the continuous track point under the original coordinate system through the plane four-parameter model, and keeping the z coordinate in the geodetic coordinate unchanged, thereby obtaining the position information of the unmanned aerial vehicle routing inspection track point.
In this step, use is made ofCalculating longitude and latitude coordinates of continuous track points in an original coordinate system, wherein X 2 、Y 2 Is the X coordinate, the y coordinate and the X coordinate of the continuous track point in the geodetic coordinates under the original coordinate system 3 、Y 3 Is the longitude and latitude coordinates of the continuous track point in the original coordinate system, delta X 0 、ΔY 0 For translation parameters, ε is the rotation parameter and m is the scale parameter. The translation parameter, the rotation parameter and the scale parameter are calculated by two pairs of control points (points with known geodetic coordinates and longitude and latitude coordinates are called control points), and the coordinates of each pair of control points in the geodetic coordinate system and the coordinates of each pair of control points in the longitude and latitude coordinate system are known.
Step 7: the three-dimensional inspection path of the unmanned aerial vehicle is obtained based on the position information of the inspection track point of the unmanned aerial vehicle, so that the position information (including longitude and latitude coordinates and elevation) of the inspection track point of the unmanned aerial vehicle can be input into the RTK centimeter-level positioning unmanned aerial vehicle terminal for autonomous flight of the unmanned aerial vehicle to realize inspection of a power transmission line.
In the above step 5-1, if the power transmission conductor corresponding to the straight line segment includes a tower, as shown in fig. 10, coordinates of each measured point on the power transmission conductor in the x-o-y plane are extracted by using the tower as a demarcation point. The density of the measured points on the electric transmission line can be used for judging the position of the tower. For example, the density function in the seaborn library is used to obtain the density of the measured points on the electric transmission line, and the density function is used to find out the x positions of the positions with obviously higher density, namely the positions of the towers (as shown in fig. 11, the positions of 7 towers can be obviously found), so as to use the x positions as demarcation points, extract the wire point cloud between the towers, and then continue to extract the coordinates of the electric transmission line.
According to the scheme, based on the laser point cloud data of the power transmission line, the wire position can be rapidly determined through downsampling, elevation filtering processing and multi-piecewise linear fitting, and then the specific position of the lightning conductor is extracted, so that the routing inspection path planning is rapidly conducted. Voxel downsampling is advantageous in terms of time cost and sampling effect compared to uniform downsampling and curvature downsampling in the wire extraction algorithm. The multi-piecewise linear fitting effect is good, the average line of each section can complete fitting within 10s, and for line distribution with non-functional properties, the x and y coordinates or piecewise fitting can be converted. The scheme is more suitable for the power transmission lines in plain areas, and when laser point cloud data are scanned, certain fitting errors can be generated if a plurality of power transmission lines exist.
The above embodiments are provided to illustrate the technical concept and features of the present invention and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be construed to be included in the scope of the present invention.
Claims (19)
1. The utility model provides a three-dimensional route planning method that patrols and examines of unmanned aerial vehicle continuous tower base based on laser point cloud for draw the coordinate of lightning conductor and plan unmanned aerial vehicle's three-dimensional route of patrolling and examining from transmission line's laser point cloud data, its characterized in that: the unmanned aerial vehicle continuous tower foundation three-dimensional inspection path planning method based on the laser point cloud comprises the following steps of:
step 1: acquiring laser point cloud data of the power transmission line, extracting plane position information and elevation information of each measured point from the laser point cloud data as information to be processed, and dividing the information to be processed into a plurality of groups according to a plurality of wire segments obtained by dividing a power transmission wire in the power transmission line;
step 2: respectively carrying out downsampling treatment on each group of information to be processed to obtain a plurality of groups of corresponding information to be filtered;
step 3: respectively carrying out elevation filtering treatment on each group of information to be filtered by using a preset elevation threshold value, and reserving plane position information and elevation information of the measured points with the elevation information higher than the elevation threshold value as information to be fitted;
step 4: performing piecewise fitting by utilizing the information to be fitted to obtain a multi-piecewise linear equation of the power transmission wire in an x-o-y plane based on geodetic coordinates;
step 5: the following steps are performed for each straight line segment of the multi-piecewise linear equation:
step 5-1: acquiring coordinates of each measured point on the electric transmission line corresponding to the straight line segment in the x-o-y plane as geodetic coordinates under an original coordinate system;
step 5-2: rotating the straight line segment in the x-o-y plane to be parallel to the x axis in the x-o-y plane, and converting to obtain the coordinates of each measured point on the electric transmission line corresponding to the straight line segment in the x-o-y plane as the coordinates in a new coordinate system;
step 5-3: setting a unit length, and equally segmenting the power transmission wires along the x-axis direction, wherein the length of each segment of power transmission wire is equal to the unit length;
step 5-4: setting matrices XB, YB and ZB, wherein the lengths of the matrices XB, YB and ZB are the number of segments for averagely segmenting the power transmission wire along the x-axis direction, the elements in the matrices XB correspond to the x-coordinate of the measured point on each segment of the power transmission wire, the elements in the matrices YB correspond to the y-coordinate of the measured point on each segment of the power transmission wire, the elements in the matrices ZB correspond to the z-coordinate of the measured point on each segment of the power transmission wire, and the initial values of the matrices XB, YB and ZB are all 0;
step 5-5: traversing each section of the power transmission wire, and for any section of the power transmission wire, if a measured point on the power transmission wire meets the condition that an x coordinate is in a corresponding segmented interval and a z coordinate is larger than a value of a corresponding element in the matrix ZB, updating the corresponding element in the matrix XB, the matrix YB and the matrix ZB by using the coordinate of the current measured point under the new coordinate system;
step 5-6: removing zero values in the matrix XB, the matrix YB and the matrix ZB;
step 5-7: extracting point cloud data of the lightning conductor under the new coordinate system based on the matrix XB, the matrix YB and the matrix ZB;
step 5-8: based on the point cloud data of the lightning conductor under the new coordinate system, shifting each point cloud data by a meter along the positive direction of the y axis and by d meters along the negative direction of the z axis to obtain the tracking wire track point coordinate of the unmanned aerial vehicle under the new coordinate system;
step 5-9: searching point cloud data of the lightning conductor in a distance of b meters from the center of each tower along the transmission conductor based on the point cloud data of the lightning conductor in the new coordinate system, and shifting the point cloud data by c meters along the positive direction of the z axis to obtain the tower and conductor connection track point coordinates of the unmanned aerial vehicle in the new coordinate system;
step 5-10: based on the tracking guide line track point coordinates of the unmanned aerial vehicle under the new coordinate system and the tower and guide line connection track point coordinates of the unmanned aerial vehicle under the new coordinate system, interpolating at the discontinuous positions of the track points to obtain the coordinates of continuous track points under the new coordinate system;
step 5-11: converting the coordinates of the continuous track points in the new coordinate system into geodetic coordinates of the continuous track points in the original coordinate system;
step 6: correspondingly converting the x coordinate and the y coordinate of the continuous track point in the geodetic coordinates under the original coordinate system into the longitude and latitude coordinates of the continuous track point under the original coordinate system, thereby obtaining the position information of the unmanned aerial vehicle inspection track point;
step 7: and obtaining a three-dimensional inspection path of the unmanned aerial vehicle based on the position information of the inspection track point of the unmanned aerial vehicle.
2. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 1, plane position information and elevation information of the measured point are extracted through a lasty library of python language.
3. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 1, the power transmission wire is divided into a plurality of wire segments according to the tower position and the number of the laser point cloud data, so that the number of the laser point cloud data corresponding to each wire segment is four tens of millions to eight tens of millions.
4. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 2, a function in an open3D library is adopted to carry out downsampling processing on the data to be processed after format conversion.
5. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 2, the information to be processed is subjected to downsampling processing by adopting uniform downsampling, voxel downsampling or curvature downsampling.
6. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 3, the elevation threshold value corresponding to each wire segment is the sum of the elevation mean value of the wire segment and a preset value.
7. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: and for the power transmission line positioned in a mountain area or a rugged terrain area, in the step 3, after the information to be filtered is ordered based on an x-axis direction coordinate or a y-axis direction, dividing the information into a plurality of small range areas, and carrying out elevation filtering processing in each small range area.
8. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 4, when the segment fitting is performed, if a segment of the power transmission line cannot form a function related to the y-axis direction in the x-axis direction, converting the x-axis direction and the y-axis direction for fitting, and performing inverse function transformation on the obtained function to obtain a corresponding linear equation; if one section of the power transmission line cannot form a function in the x-axis direction and the y-axis direction, the power transmission line is segmented again and then segmented fitting is carried out.
9. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 5, the piecewise point of the multi-piecewise linear equation is a tower position.
10. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 5-1, the density of the measured point on the power transmission wire is obtained by using a density function in a seaborn library, and then the position of the tower is judged by using the density of the measured point on the power transmission wire.
11. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the steps 5-8, the value of a is 2, the value of d is determined by the voltage level of the power transmission line, and the value of d is 2, 3.5, 6 or 10.
12. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the steps 5-9, the value of b is 10, and the value of c is 2.
13. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the steps 5-10, linear interpolation is performed at the discontinuous position of the navigation points.
14. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 6, the x coordinate and the y coordinate in the geodetic coordinates of the continuous track points in the original coordinate system are correspondingly converted into the longitude and latitude coordinates of the continuous track points in the original coordinate system through a plane four-parameter model.
15. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 7, the position information of the unmanned aerial vehicle inspection track point is input into an unmanned aerial vehicle terminal for autonomous flight.
16. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud as defined in claim 1, wherein the method is characterized by comprising the following steps: in the step 5-2, the rotation angle of the straight line segment is equal to alpha based on the slope tan alpha of the straight line segment, and thenCalculating the coordinates of each measured point on the electric transmission line corresponding to the straight line segment under the new coordinate system, wherein ∈>Has the value of-alpha, X 1 、Y 1 Is the X coordinate, y coordinate and X coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the original coordinate system 1 T 、Y 1 T Is the x coordinate and the y coordinate of each measured point on the electric transmission line corresponding to the straight line segment under the new coordinate system.
17. The laser point cloud based unmanned aerial vehicle continuous tower base three-dimensional inspection path planning method according to claim 16, wherein the method comprises the following steps: in the steps 5-11, use is made ofCalculating the geodetic coordinates of the successive track points in said original coordinate system, wherein +.>Has the value alpha, X 2 、Y 2 、Z 2 Is the x-coordinate, y-coordinate, z-coordinate of the successive track points in said original coordinate system,/-coordinate>Is the x-coordinate, y-coordinate, z-coordinate of the successive track points in the new coordinate system.
18. The unmanned aerial vehicle continuous tower footing three-dimensional inspection path planning method based on the laser point cloud of claim 17, wherein the method comprises the following steps: in the step 6, use is made ofCalculating longitude and latitude coordinates of continuous track points in the original coordinate system, wherein X 2 、Y 2 Is the X coordinate, the y coordinate and the X coordinate of the continuous track point in the geodetic coordinates under the original coordinate system 3 、Y 3 Is the longitude and latitude sitting of the continuous track point under the original coordinate systemMark, deltaX 0 、ΔY 0 For translation parameters, ε is the rotation parameter and m is the scale parameter.
19. The laser point cloud based unmanned aerial vehicle continuous tower base three-dimensional inspection path planning method according to claim 18, wherein the method comprises the following steps: the translation parameter, the rotation parameter and the scale parameter are obtained through calculation of two pairs of control points, and the coordinates of each pair of control points in a geodetic coordinate system and the coordinates of each pair of control points in a longitude and latitude coordinate system are known.
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CN117115491B (en) * | 2023-08-18 | 2024-04-09 | 国网山东省电力公司临沂供电公司 | Method, system and storage medium for extracting protection angle of lightning conductor of power transmission tower pole based on laser point cloud data |
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