Inspection route auxiliary point generation method based on safety bounding box

Abstract

The invention relates to the field of unmanned aerial vehicle inspection, and discloses an inspection route auxiliary point generation method based on a safety bounding box. According to the method, a safety bounding box is constructed on a single tower of a power transmission tower, and a to-be-flied inspection point is obtained. And projecting the inspection points to the safety bounding box to obtain auxiliary points through which the unmanned aerial vehicle needs to fly, obtaining access points of the safety bounding box, traversing each auxiliary point from the access points, and constructing an inspection route of the unmanned aerial vehicle. According to the method, the safety and the quality of the route of the unmanned aerial vehicle are comprehensively considered, and the auxiliary points in the route are constructed according to the safety bounding box, so that the unmanned aerial vehicle can fly at the inspection points and the auxiliary points in sequence, the generation speed and the generation quality of the auxiliary points are improved, and a firm guarantee is provided for route planning; meanwhile, the algorithm of the generation method is lightweight, is adjusted according to the existing environment, and is convenient to deploy and use.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle inspection, and in particular to a method for generating auxiliary points of an inspection route based on a safety bounding box. Background Art

[0002] With the maturity of drone technology, it has become a trend to use drone inspection to maintain the stable operation of the power grid. At present, ground staff mainly conduct fault analysis based on the pictures sent back by the visual camera on the drone, and the drone's line inspection method is to mechanically shoot the pole tower and its components according to the set route. The route is generally composed of inspection points and flight assistance points. The inspection points are the objects on the power pole tower that the drone needs to shoot. The flight assistance points are points added between the inspection points to ensure the safety of the drone when inspecting the pole tower. The inspection points are generally fixed, and the flight assistance points are set manually. At the same time, people generally judge the feasibility of the auxiliary flight points based on experience and vision in the power pole tower simulation environment. The intelligence is insufficient. At the same time, because the flight assistance points are generated by manual operation, it is necessary to carefully judge the spatial relationship of any inspection point one by one to generate appropriate flight assistance points to ensure the quality and safety of the route, resulting in low efficiency. In addition, the manually generated flight assistance points often give priority to ensuring the safety of the drone's flight, but ignore the influence of the location of the flight assistance points on the total distance of the route, resulting in low quality of the generated route. Summary of the invention

[0003] In order to overcome the above technical problems, the present invention provides a method for generating auxiliary points for inspection routes based on a safety bounding box. Through the above method, the generation method comprehensively considers the safety and quality of the drone's route, and constructs auxiliary points in the route according to the safety bounding box, so that the drone can complete the flight at the inspection points and auxiliary points in order, thereby improving the speed and quality of auxiliary point generation and providing a solid guarantee for route planning; at the same time, the algorithm of the generation method is lightweight and can be adjusted according to the existing environment, which is easy to deploy and use. In order to achieve the above purpose, the present invention provides a method for generating auxiliary points for inspection routes based on a safety bounding box, and the generation method includes:

[0004] Construct a safety enclosing box on a single transmission tower;

[0005] Get the inspection points to be flown;

[0006] Projecting the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly over;

[0007] Obtaining the entry and exit points of the safety bounding box;

[0008] Starting from the entry and exit points, each of the auxiliary points is traversed to construct the inspection route of the drone.

[0009] Preferably, a safety enclosing box is constructed in a single transmission tower, including:

[0010] Acquiring point cloud data within the transmission tower;

[0011] Determine, according to the point cloud data, to decompose the transmission tower into a plurality of geometric point sets;

[0012] The mean of the geometric point set is determined according to formula (1):

[0013]

[0014] Among them, μ is the mean, n is the number of samples of the geometric point set, a i 、b i and c i are the endpoints of the geometric point set;

[0015] The covariance matrix of the geometric point set is determined according to formula (2):

[0016]

[0017] in, is the endpoint a of the i-th geometric point set i The j-th dimension coordinate of is the endpoint b of the i-th geometric point set i The j-th dimension coordinate of is the endpoint c of the i-th geometric point set i The j-th dimension coordinate of is the endpoint a of the i-th geometric point set i The k-th dimension coordinate of is the endpoint b of the i-th geometric point set i The k-th dimension coordinate of is the endpoint c of the i-th geometric point set i The k-th dimension coordinate, C jk is the kth element in the jth row of the covariance matrix,

[0018] Obtain three mutually perpendicular eigenvectors according to the covariance matrix;

[0019] Performing a normalization operation on the feature vector to obtain coordinate axes in three directions of the OBB bounding box of the transmission tower;

[0020] Determine the two farthest points of the point cloud data in the direction of the coordinate axis;

[0021] The safety bounding box is determined according to the two farthest points and a preset safety distance.

[0022] Preferably, the inspection points are projected onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including:

[0023] Traversing each of the inspection points, determining two side surfaces in the safety enclosing box parallel to the line of the transmission tower and the top surface of the safety enclosing box as projection surfaces of the inspection point, so as to obtain a left plane, a right plane and an upper plane;

[0024] Determine the distance between the inspection point and the left plane, the right plane and the upper plane;

[0025] When the inspection point is closest to the left plane, obtaining a projection point of the inspection point on the left plane as a first projection point;

[0026] Determine whether the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than a preset inspection safety distance;

[0027] When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected;

[0028] When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, obtaining the projection point of the inspection point on the upper plane as the second projection point;

[0029] Determine whether the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0030] When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected;

[0031] When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a distance correction operation is performed on the first projection point to obtain a point to be corrected;

[0032] When the distance between the inspection point and the right plane is the shortest, obtaining a projection point of the inspection point on the right plane as a first projection point;

[0033] Determine whether the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than a preset inspection safety distance;

[0034] When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected;

[0035] When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, obtaining the projection point of the inspection point on the upper plane as the second projection point;

[0036] Determine whether the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0037] When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected;

[0038] When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a distance correction operation is performed on the first projection point to obtain a point to be corrected;

[0039] When the distance between the inspection point and the upper plane is the shortest, the inspection point is projected onto the upper plane to obtain the first projection point;

[0040] Determine whether the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0041] When the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected;

[0042] When the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, select the left plane or the right plane with the smallest distance from the inspection point for projection to obtain the second projection point;

[0043] Determine whether the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0044] When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected;

[0045] When the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, the inspection point is re-projected on the upper plane and a distance correction is performed to obtain the point to be corrected.

[0046] Preferably, the inspection points are projected onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including:

[0047] The straight line within the safety bounding box and the transmission tower is taken as the X-axis, the straight line perpendicular to the straight line and located in the horizontal plane is taken as the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is taken as the Z-axis;

[0048] Obtaining the two inspection points and the corresponding points to be corrected;

[0049] Obtain the distances between the inspection points and the points to be corrected as waypoint distances;

[0050] Determine whether the waypoint distances are all greater than a preset limit distance;

[0051] In the case where the waypoint distance is greater than the limited distance, determining whether the distance correction operation has been performed on the point to be corrected;

[0052] In the case where the distance correction operation has not been performed, taking the point to be corrected as the auxiliary point;

[0053] In the case where the distance correction operation has been performed on the point to be corrected, determining the plane where the point to be corrected is located;

[0054] When the plane where the point to be corrected is located is the left plane or the right plane, the Y-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Y-axis coordinate before correction, so as to obtain the auxiliary point;

[0055] When the plane where the point to be corrected is located is the upper plane, the Z-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Z-axis coordinate before correction, so as to obtain the auxiliary point;

[0056] In the case where the distance of any of the waypoints is less than or equal to the limited distance, determining the projection surface closest to each of the inspection points;

[0057] Acquire a corresponding projection point on the projection surface as a new point to be corrected;

[0058] Correct the point to be corrected according to formula (3) to obtain the auxiliary point.

[0059]

[0060] Among them, δ is the offset distance, θ is the limit distance, a is the inspection point, b is the projection point, d ab is the distance between a and b.

[0061] Preferably, the inspection points are projected onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including:

[0062] Expanding the safety bounding box to obtain an expanded plane;

[0063] Determine a line connecting the auxiliary points corresponding to any two inspection points on the unfolded plane;

[0064] The intersection point of the connecting line and the edge of the safety bounding box is determined as a connection point.

[0065] Preferably, the inspection points are projected onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including:

[0066] Uniformly downsampling the point cloud data of the transmission tower to obtain simplified point cloud data;

[0067] Traversing every two inspection points, obtaining the auxiliary points and connection points corresponding to the two inspection points;

[0068] Determine a connection path between the two inspection points;

[0069] Performing a discrete operation on the connection path to obtain inspection point cloud data;

[0070] Calculate the shortest distance between the inspection point cloud data and the simplified point cloud data, and use it as the minimum safety distance;

[0071] Determine whether the minimum safety distance is less than the preset inspection safety distance;

[0072] When the minimum safety distance is greater than or equal to the inspection safety distance, all auxiliary points and connection points corresponding to the two inspection points are deleted.

[0073] Preferably, the method further comprises:

[0074] Obtaining relative positions of the access points of different transmission towers;

[0075] The inspection routes between different transmission towers are determined according to the preset inspection order of the transmission towers and the positions of the entry and exit points.

[0076] Preferably, the inspection routes between different transmission towers are determined according to the preset inspection order of the transmission towers and the positions of the entry and exit points, including:

[0077] Determine the starting tower and the ending tower of the inspection route;

[0078] Determine all intermediate points and transition points passed between the starting tower and the ending tower;

[0079] The intermediate point and the transition point are connected to obtain the inspection route.

[0080] Preferably, determining all intermediate points and transition points passed between the starting tower and the ending tower comprises:

[0081] Taking a point at a preset height above the highest point in the point cloud data of each transmission tower between the starting tower and the ending tower as the intermediate point;

[0082] The set consisting of the intermediate point, the entry and exit points of the starting tower and the ending tower is used as the flight point set;

[0083] Determine whether the heights of every two adjacent flight points are equal;

[0084] In the case where the heights of two adjacent flight points are not equal, a transition point is set above the lower one of the two adjacent flight points, and the height of the transition point is equal to the higher one of the two adjacent flight points.

[0085] Preferably, the inspection routes between different transmission towers are determined according to the preset inspection order of the transmission towers and the positions of the entry and exit points, including:

[0086] Obtaining the intermediate point;

[0087] Calculate the distance between each two intermediate points and sort them from small to large;

[0088] Generate a path between the intermediate points according to a greedy rule;

[0089] Determining whether the number of switching times of the path reaches a preset threshold;

[0090] When the number of exchanges reaches a preset threshold, saving the current path between the intermediate points as the inspection route;

[0091] When the number of exchanges does not reach a preset threshold, the path segments in the path are exchanged, and the exchanged path is calculated;

[0092] determining whether the length of the path decreases;

[0093] In the case where the length of the path is reduced, the exchanged path is used as a new path, and the process returns to the step of determining whether the number of exchanges of the path reaches a preset threshold;

[0094] In the case that the length of the path is not reduced, the process returns to the step of determining whether the number of exchanges of the path reaches a preset threshold.

[0095] Through the above technical scheme, the generation method constructs a safety bounding box on the point cloud data of the transmission tower, which tightly surrounds the object and meets the uniformity of the modeling specification; and the inspection points that the drone needs to fly are projected onto the safety bounding box to generate auxiliary points, and the connection points of the drone flight on the safety bounding box are generated according to the auxiliary points, and the entry and exit points of the drone on the safety bounding box are preset. The drone passes through the entry and exit points, inspection points, and auxiliary points in the order of flight to construct the inspection route; at the same time, according to the relative positions of the entry and exit points of different transmission towers, and the middle point of the middle tower to be flown through is obtained, the transition point between the flight points is obtained, and the shortest connection path between multiple middle points is constructed. The drone flies through the entry and exit points, transition points and middle points in order to realize the generation of the drone's cross-tower route; under the condition of ensuring flight safety, the generation method improves the speed and quality of the generation of auxiliary points, middle points and other position points that are convenient for auxiliary flight, greatly shortens the flight distance of the drone, and provides a reliable guarantee for route planning; at the same time, the algorithm of the generation method is lightweight and adjusted according to the existing environment, which is convenient for deployment and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0096] Figure 1 is a flow chart of a method for generating auxiliary points of an inspection route based on a safety bounding box according to an embodiment of the present invention;

[0097] Figure 2 , 3 It is a schematic block diagram of judging the generation of points to be corrected in a method for generating auxiliary points of an inspection route based on a safety bounding box according to an embodiment of the present invention;

[0098] Figure 4 It is a schematic block diagram of judging auxiliary point generation of a method for generating auxiliary points of an inspection route based on a safety bounding box according to an embodiment of the present invention;

[0099] Figure 5 It is a schematic block diagram of the determination of connection point reduction of a method for generating auxiliary points of inspection routes based on a safety bounding box according to an embodiment of the present invention;

[0100] Figure 6 It is a schematic block diagram of judging the generation of paths between intermediate points in a method for generating auxiliary points for inspection routes based on a safety bounding box according to an embodiment of the present invention. DETAILED DESCRIPTION

[0101] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0102] like Figure 1 FIG. 1 is a flow chart of a method for generating auxiliary points of inspection routes based on a safety bounding box according to an embodiment of the present invention; Figure 1 In the method, the method may include the following steps:

[0103] In step S10, a safety bounding box is constructed on a single transmission tower.

[0104] In step S11, the inspection points to be flown are obtained.

[0105] In step S12, the inspection points are projected onto the safety bounding box to obtain auxiliary points that the UAV needs to fly over.

[0106] In step S13, the entry and exit points of the safety bounding box are obtained.

[0107] In step S14, starting from the entry and exit points, each auxiliary point is traversed to construct the inspection route of the drone.

[0108] exist Figure 1 In step S10, the point cloud data of the transmission tower is obtained, and the point cloud data is decomposed into multiple geometric point sets, and the coordinate axes of the OBB bounding box of the transmission tower in three directions are obtained by calculation based on the geometric point sets, and the two farthest points of the point cloud data in the direction of the coordinate axis are determined; the safety bounding box is determined according to the two farthest points in the point cloud data and the preset safety distance.

[0109] Step S11 obtains the inspection points to be flown inside the transmission tower.

[0110] In step S12, the inspection points are first projected onto the surface of a suitable safety bounding box according to the projection rule to obtain projection points. After processing the projection points, auxiliary points that the UAV needs to pass during flight are obtained.

[0111] Step S13 obtains a safety bounding box according to a single transmission tower, obtains the midpoints of the highest sides of the symmetrical sides of the safety bounding box, and sets them as entry and exit points.

[0112] Step S14 obtains the auxiliary points that the drone needs to pass through. The drone starts from the entry and exit points and passes through the auxiliary points in order to obtain the inspection route of the drone.

[0113] Through the above method, the generation method comprehensively considers the safety and quality of the UAV's route, and constructs auxiliary points in the route according to the safety bounding box, so that the UAV can complete the flight at the inspection points and auxiliary points in order, which improves the speed and quality of auxiliary point generation and provides a solid guarantee for route planning; at the same time, the algorithm of the generation method is lightweight and can be adjusted according to the existing environment, which is easy to deploy and use.

[0114] In order to construct a safety bounding box of a single transmission tower and avoid collision between the UAV and the tower during inspection, in one embodiment of the present invention, point cloud data in the transmission tower is first obtained, and the transmission tower is decomposed into multiple geometric point sets according to the point cloud data, and the mean of the geometric point sets is determined according to formula (1).

[0115]

[0116] Among them, μ is the mean, n is the number of samples of the geometric point set, a i 、b i and c i is the endpoint of the geometric point set;

[0117] According to formula (2), the covariance matrix of the geometric point set is determined:

[0118]

[0119] in, is the endpoint a of the i-th geometric point set i The j-th dimension coordinate of is the endpoint b of the i-th geometric point set i The j-th dimension coordinate of is the endpoint c of the i-th geometric point set i The j-th dimension coordinate of is the endpoint a of the i-th geometric point set i The k-th dimension coordinate of is the endpoint b of the i-th geometric point set i The k-th dimension coordinate of is the endpoint c of the i-th geometric point set i The k-th dimension coordinate, C jk is the kth element in the jth row of the covariance matrix, At the same time, three mutually perpendicular eigenvectors are obtained according to the covariance matrix, and the eigenvectors are standardized to obtain the coordinate axes of the OBB bounding box of the transmission tower in three directions. The two farthest points of the point cloud data in the direction of the coordinate axis are determined, and the AABB bounding box of the transmission tower is obtained by line expansion. The safety distance is set on the three direction axes of the AABB bounding box to obtain a safety protection box.

[0120] like Figure 2 and 3 FIG. 1 is a schematic diagram showing the determination of the generation of points to be corrected in a method for generating auxiliary points of an inspection route based on a safety bounding box according to an embodiment of the present invention; FIG. Figure 2 and 3 In the design, considering that the drone will hit the tower when flying in a straight line between two inspection points, it is necessary to generate several auxiliary points according to the positions of the two inspection points to help the drone adjust the flight track. For the inside of the tower, that is, the area near the tower, the surrounding wires and ground wires are complicated, and the flight safety of the drone is greatly threatened. Therefore, a regular route is designed according to the safety bounding box. In one embodiment of the present invention, the inspection points can be projected onto the safety bounding box according to the faces of the cube of the safety bounding box to obtain the auxiliary points that the drone needs to fly through.

[0121] In step S200, each inspection point is traversed to determine the two side surfaces in the safety enclosing box parallel to the line of the transmission tower and the top surface of the safety enclosing box as the projection surfaces of the inspection point to obtain the left plane, the right plane and the upper plane; the distance between the inspection point and the left plane, the right plane and the upper plane is determined;

[0122] In step S201, when the inspection point is closest to the left plane or the right plane, a projection point of the inspection point on the left plane is obtained as a first projection point;

[0123] In step S202, it is determined whether the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than a preset inspection safety distance;

[0124] In step S204, when the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected;

[0125] In step S203, when the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, the projection point of the inspection point on the upper plane is obtained as the second projection point;

[0126] In step S205, it is determined whether the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0127] In step S207, when the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected;

[0128] In step S206, when the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a distance correction operation is performed on the first projection point to obtain a point to be corrected;

[0129] In step S208, when the inspection point is closest to the upper plane, the inspection point is projected onto the upper plane to obtain a first projection point;

[0130] In step S209, it is determined whether the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0131] In step S211, when the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected;

[0132] In step S210, when the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a left plane or a right plane with the smallest distance from the inspection point is selected for projection to obtain a second projection point;

[0133] In step S212, it is determined whether the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance;

[0134] In step S214, when the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected;

[0135] In step S213, when the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, the inspection point is re-projected on the upper plane and the distance correction is performed to obtain the point to be corrected.

[0136] In general, when projecting inspection points, the faces that are close to the safety bounding box are given priority. Then, when the line connecting the projection point and the inspection point is too close to the surrounding environment entity, other faces are selected for secondary projection. If the secondary projection is still too close to the surrounding environment entity, the distance can only be corrected on the basis of the first projection to obtain the required projection point as the point to be corrected, which is convenient for the subsequent generation of auxiliary points of the drone and ensures that the drone has a safe distance from the environmental entity during flight.

[0137] like Figure 4 FIG. 1 is a schematic diagram showing the determination of auxiliary point generation in a method for generating auxiliary points for inspection routes based on a safety bounding box according to an embodiment of the present invention; FIG. Figure 4In the present invention, considering that when the inspection points are projected, the distances between the generated projection points, the inspection points, and the projection points and the inspection points are too small, which will affect the generation of the flight trajectory, in one embodiment of the present invention, the straight line where the line of the transmission tower is located in the safety bounding box is taken as the X-axis, the straight line perpendicular to the straight line where the line is located and located in the horizontal plane is taken as the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is taken as the Z-axis; two inspection points and the corresponding points to be corrected are obtained; the distances between the inspection points and the points to be corrected are obtained as the waypoint distances;

[0138] In step S30, it is determined whether the waypoint distances are all greater than a preset limit distance;

[0139] In step S31, when the waypoint distance is greater than the specified distance, it is determined whether the point to be corrected has performed a distance correction operation;

[0140] In step S33, in the case where the distance correction operation has not been performed, the point to be corrected is used as an auxiliary point;

[0141] In step S32, when the distance correction operation has been performed on the point to be corrected, the plane where the point to be corrected is located is determined;

[0142] In step S35, when the plane where the point to be corrected is located is the left plane or the right plane, the Y-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Y-axis coordinate before correction, so as to obtain an auxiliary point;

[0143] In step S34, when the plane where the point to be corrected is located is the upper plane, the Z-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Z-axis coordinate before correction, so as to obtain an auxiliary point;

[0144] In step S36, when the distance of any waypoint is less than or equal to the defined distance, the projection surface closest to each inspection point is determined;

[0145] In step S37, the corresponding projection point is obtained on the projection surface as a new point to be corrected; the point to be corrected is corrected according to formula (3) to obtain an auxiliary point.

[0146]

[0147] Among them, δ is the offset distance, θ is the limit distance, a is the inspection point, b is the projection point, d abis the distance between a and b. When generating projection points, projection is first performed directly, and then the distance between the generated projection points, between the inspection points, and between the projection points and the inspection points is determined to be greater than the specified distance, and the point to be corrected can be used as an auxiliary point. However, when the distance is less than the specified distance, the inspection point can only be directly projected according to the principle of proximity to obtain the projection point as the new point to be corrected, and then the offset distance is corrected to obtain the auxiliary point, which ensures that the distance between the waypoints is not too close, thereby generating a safe flight route.

[0148] Considering that the generated auxiliary points can generate connection points of auxiliary points that facilitate the flight of the drone based on the safety bounding box, in one embodiment of the present invention, the safety bounding box is unfolded to obtain an unfolded plane; the connecting line of the auxiliary points corresponding to any two inspection points on the unfolded plane is determined, and the intersection of the connecting line and the edge of the safety bounding box is determined as the connecting point. The connecting point and the auxiliary point are used to assist the flight, and the distance between the auxiliary points formed in this way is the shortest, thereby improving the quality of the guaranteed route.

[0149] like Figure 5 FIG. 1 is a schematic block diagram showing the determination of connection point reduction in a method for generating auxiliary points of inspection routes based on a safety bounding box according to an embodiment of the present invention; FIG. Figure 5 In the invention, when two inspection points on the same side can be directly connected, no auxiliary points and connection points are required, which can greatly reduce the number of auxiliary points and connection points; thereby improving flight efficiency, the number of auxiliary points and connection points can be reduced as much as possible by judging whether the inspection points can be directly connected; in one embodiment of the present invention, the following operations can be performed:

[0150] In step S40, the point cloud data of the transmission tower is uniformly downsampled to obtain simplified point cloud data;

[0151] In step S41, traverse every two inspection points to obtain the auxiliary points and connection points corresponding to the two inspection points;

[0152] In step S42, a connection path between two inspection points is determined;

[0153] In step S43, a discrete operation is performed on the connection path to obtain inspection point cloud data;

[0154] In step S44, the shortest distance between the inspection point cloud data and the simplified point cloud data is calculated and used as the minimum safety distance;

[0155] In step S45, it is determined whether the minimum safety distance is less than the preset inspection safety distance;

[0156] In step S46, when the minimum safety distance is greater than or equal to the inspection safety distance, all auxiliary points and connection points corresponding to the two inspection points are deleted.

[0157] In order to meet the generation of inspection routes between different transmission towers and the need for cross-tower flight, based on the known basic information of the intermediate towers between different transmission towers, in one embodiment of the present invention, the relative positions of the entry and exit points of different transmission towers are obtained; the inspection routes between different transmission towers are determined according to the preset inspection order of the transmission towers and the positions of the entry and exit points. Based on the information between the starting tower and the ending tower and the intermediate towers, the intermediate tower can be used as an environmental support for the construction of the route, so that the route between different transmission towers meets the safety requirements and the quality of the route can also be guaranteed.

[0158] Considering that the locations of the entry and exit points should be convenient for the UAV to fly across the tower, while also providing diversified options for the choice of cross-tower methods, reasonable processing is performed based on the point cloud data of the middle tower between the starting tower and the ending tower to obtain the environmental support of the middle tower, avoid colliding with the middle tower during the cross-tower flight, and thus construct a safe inspection route. In one embodiment of the present invention, the starting tower and the ending tower of the inspection route can be first determined, and then all the intermediate points and transition points passed between the starting tower and the ending tower can be determined; the intermediate points and transition points are connected to obtain the inspection route. At this time, the intermediate points and transition points are used to assist the UAV flight, avoid the influence of environmental factors, and ensure the safe flight of the UAV.

[0159] Considering the convenience of UAVs to quickly enter and exit the tower, the inspection route between the starting tower and the ending tower of the UAV is constructed. It is necessary to reasonably process the point cloud data of the middle tower between the starting tower and the ending tower to obtain the support of the environment of the middle tower; at the same time, to avoid the UAV from flying in the middle tower, in one embodiment of the present invention, the point at a preset height above the highest point in the point cloud data of each transmission pole tower between the starting tower and the ending tower is taken as the middle point; the set consisting of the middle point, the entry and exit points of the starting tower and the ending tower is taken as the flight point set; it is judged whether the heights of each two adjacent flight points are equal; when the heights of the two adjacent flight points are not equal, a transition point is set above the lower of the two adjacent flight points, and the height of the transition point is equal to the higher of the two adjacent flight points. The intermediate point formed in this way is based on the top of the highest point of the middle tower between the starting tower and the ending tower, which not only meets the actual needs, but also can fully consider the structural characteristics and terrain factors of the pole tower, meet the generation of the inspection route between the starting tower and the ending tower, and at the same time, the transition point generated based on the height relationship between the two adjacent flight points can solve the problem of the UAV passing through the inside of the middle tower, and prevent the collision of the UAV with the tower body.

[0160] like Figure 6is a schematic diagram of judging the path generation between the intermediate points of the inspection route auxiliary point generation method based on the safety bounding box according to an embodiment of the present invention; Figure 6 In the process, considering the different orders of passing through the intermediate towers in the inspection route and the different flying distances of the drone, the reasonable planning of the access order of each intermediate point should ensure that each point is visited and the total distance of the route is minimized. At the same time, considering that the flight time of the drone is limited and the number of intermediate towers is generally small, in one embodiment of the present invention, it is necessary to obtain the intermediate points of the intermediate towers and perform algorithmic calculations on the paths between the intermediate points to obtain the shortest path:

[0161] In step S50, the distance between every two intermediate points is calculated and sorted from small to large;

[0162] In step S51, a path between intermediate points is generated according to a greedy rule;

[0163] In step S52, it is determined whether the number of path switching times reaches a preset threshold;

[0164] In step S56, when the number of exchanges reaches a preset threshold, the current path between the intermediate points is saved as an inspection route;

[0165] In step S53, when the number of exchanges does not reach a preset threshold, the path segments in the path are exchanged, and the exchanged path is calculated;

[0166] In step S54, it is determined whether the length of the path is reduced;

[0167] In step S55, when the length of the path is reduced, the exchanged path is used as a new path, and the process returns to the step of determining whether the number of exchange times of the path reaches a preset threshold;

[0168] At the same time, if the length of the path is not reduced, the step of determining whether the number of path exchanges reaches the preset threshold is returned. Through the above steps, the path sorting between the intermediate points obtained according to the greedy rule can find the shortest distance for the drone to fly across the tower, and the inspection route obtained is of high quality.

[0169] Through the above technical scheme, the generation method constructs a safety bounding box on the point cloud data of the transmission tower, which tightly surrounds the object and meets the uniformity of the modeling specification; and the inspection points that the drone needs to fly are projected onto the safety bounding box to generate auxiliary points, and the connection points of the drone flight on the safety bounding box are generated according to the auxiliary points, and the entry and exit points of the drone on the safety bounding box are preset. The drone passes through the entry and exit points, inspection points, and auxiliary points in the order of flight to construct the inspection route; at the same time, according to the relative positions of the entry and exit points of different transmission towers, and the middle point of the middle tower to be flown through is obtained, the transition point between the flight points is obtained, and the shortest connection path between multiple middle points is constructed. The drone flies through the entry and exit points, transition points and middle points in order to realize the generation of the drone's cross-tower route; under the condition of ensuring flight safety, the generation method improves the speed and quality of the generation of auxiliary points, middle points and other points that are convenient for auxiliary flight, greatly shortens the flight distance of the drone, and provides a reliable guarantee for route planning; at the same time, the algorithm of the generation method is lightweight and adjusted according to the existing environment, which is convenient for deployment and use.

[0170] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0171] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A method for generating auxiliary points of inspection routes based on safety bounding boxes, characterized in that: The generation method comprises: Construct a safety enclosing box on a single transmission tower; Get the inspection points to be flown; Projecting the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly over; Obtaining the entry and exit points of the safety bounding box; Starting from the entry and exit points, each of the auxiliary points is traversed to construct the inspection route of the drone.

2. The generation method according to claim 1, characterized in that: Construct a safety bounding box inside a single transmission tower, including: Acquiring point cloud data within the transmission tower; Determine, according to the point cloud data, to decompose the transmission tower into a plurality of geometric point sets; The mean of the geometric point set is determined according to formula (1): Among them, μ is the mean, n is the number of samples of the geometric point set, a i 、b i and c i are the endpoints of the geometric point set; The covariance matrix of the geometric point set is determined according to formula (2): in, is the endpoint a of the i-th geometric point set i The j-th dimension coordinate of is the endpoint b of the i-th geometric point set i The j-th dimension coordinate of is the endpoint c of the i-th geometric point set i The j-th dimension coordinate of is the endpoint a of the i-th geometric point set i The k-th dimension coordinate of is the endpoint b of the i-th geometric point set i The k-th dimension coordinate of is the endpoint c of the i-th geometric point set i The k-th dimension coordinate, C jk is the kth element in the jth row of the covariance matrix, Obtain three mutually perpendicular eigenvectors according to the covariance matrix; Performing a normalization operation on the feature vector to obtain coordinate axes in three directions of the OBB bounding box of the transmission tower; Determine the two farthest points of the point cloud data in the direction of the coordinate axis; The safety bounding box is determined according to the two farthest points and a preset safety distance.

3. The generation method according to claim 1, characterized in that: Project the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including: Traversing each of the inspection points, determining two side surfaces in the safety enclosing box parallel to the line of the transmission tower and the top surface of the safety enclosing box as projection surfaces of the inspection point, so as to obtain a left plane, a right plane and an upper plane; Determine the distance between the inspection point and the left plane, the right plane and the upper plane; When the inspection point is closest to the left plane, obtaining a projection point of the inspection point on the left plane as a first projection point; Determine whether the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than a preset inspection safety distance; When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected; When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, obtaining the projection point of the inspection point on the upper plane as the second projection point; Determine whether the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance; When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected; When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a distance correction operation is performed on the first projection point to obtain a point to be corrected; When the distance between the inspection point and the right plane is the shortest, obtaining a projection point of the inspection point on the right plane as a first projection point; Determine whether the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than a preset inspection safety distance; When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected; When the minimum distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, obtaining the projection point of the inspection point on the upper plane as the second projection point; Determine whether the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance; When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected; When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, a distance correction operation is performed on the first projection point to obtain a point to be corrected; When the distance between the inspection point and the upper plane is the shortest, the inspection point is projected onto the upper plane to obtain the first projection point; Determine whether the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance; When the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the first projection point is used as the point to be corrected; When the distance between the line connecting the first projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, select the left plane or the right plane with the smallest distance from the inspection point for projection to obtain the second projection point; Determine whether the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance; When the minimum distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is greater than or equal to the inspection safety distance, the second projection point is used as the point to be corrected; When the distance between the line connecting the second projection point and the inspection point and the surrounding environment entity is less than the inspection safety distance, the inspection point is re-projected on the upper plane and a distance correction is performed to obtain the point to be corrected.

4. The generation method according to claim 3, characterized in that: Project the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including: The straight line within the safety bounding box and the transmission tower is taken as the X-axis, the straight line perpendicular to the straight line and located in the horizontal plane is taken as the Y-axis, and the direction perpendicular to the X-axis and the Y-axis is taken as the Z-axis; Obtaining the two inspection points and the corresponding points to be corrected; Obtain the distances between the inspection points and the points to be corrected as waypoint distances; Determine whether the waypoint distances are all greater than a preset limit distance; In the case where the waypoint distance is greater than the limited distance, determining whether the distance correction operation has been performed on the point to be corrected; In the case where the distance correction operation has not been performed, taking the point to be corrected as the auxiliary point; In the case where the distance correction operation has been performed on the point to be corrected, determining the plane where the point to be corrected is located; When the plane where the point to be corrected is located is the left plane or the right plane, the Y-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Y-axis coordinate before correction, so as to obtain the auxiliary point; When the plane where the point to be corrected is located is the upper plane, the Z-axis coordinate of the point to be corrected is corrected to the sum of the preset point cloud safety distance and the Z-axis coordinate before correction, so as to obtain the auxiliary point; In the case where the distance of any of the waypoints is less than or equal to the limited distance, determining the projection surface closest to each of the inspection points; Acquire a corresponding projection point on the projection surface as a new point to be corrected; Correct the point to be corrected according to formula (3) to obtain the auxiliary point. Among them, δ is the offset distance, θ is the limit distance, a is the inspection point, b is the projection point, d ab is the distance between a and b.

5. The generation method according to claim 4, characterized in that: Project the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including: Expanding the safety bounding box to obtain an expanded plane; Determine a line connecting the auxiliary points corresponding to any two inspection points on the unfolded plane; The intersection point of the connecting line and the edge of the safety bounding box is determined as a connection point.

6. The generation method according to claim 5, characterized in that: Project the inspection points onto the safety bounding box to obtain auxiliary points that the drone needs to fly through, including: Uniformly downsampling the point cloud data of the transmission tower to obtain simplified point cloud data; Traversing every two inspection points, obtaining the auxiliary points and connection points corresponding to the two inspection points; Determine a connection path between the two inspection points; Performing a discrete operation on the connection path to obtain inspection point cloud data; Calculate the shortest distance between the inspection point cloud data and the simplified point cloud data, and use it as the minimum safety distance; Determine whether the minimum safety distance is less than the preset inspection safety distance; When the minimum safety distance is greater than or equal to the inspection safety distance, all auxiliary points and connection points corresponding to the two inspection points are deleted.

7. The generation method according to claim 1, characterized in that: The method further comprises: Obtaining relative positions of the access points of different transmission towers; The inspection routes between different transmission towers are determined according to the preset inspection order of the transmission towers and the positions of the entry and exit points.

8. The generation method according to claim 7, characterized in that: According to the preset inspection order of the transmission towers and the positions of the entry and exit points, the inspection routes between different transmission towers are determined, including: Determine the starting tower and the ending tower of the inspection route; Determine all intermediate points and transition points passed between the starting tower and the ending tower; The intermediate point and the transition point are connected to obtain the inspection route.

9. The generation method according to claim 8, characterized in that: Determine all intermediate points and transition points between the starting tower and the ending tower, including: Taking a point at a preset height above the highest point in the point cloud data of each transmission tower between the starting tower and the ending tower as the intermediate point; The set consisting of the intermediate point, the entry and exit points of the starting tower and the ending tower is used as the flight point set; Determine whether the heights of every two adjacent flight points are equal; In the case where the heights of two adjacent flight points are not equal, a transition point is set above the lower one of the two adjacent flight points, and the height of the transition point is equal to the higher one of the two adjacent flight points.

10. The generation method according to claim 9, characterized in that: According to the preset inspection order of the transmission towers and the positions of the entry and exit points, the inspection routes between different transmission towers are determined, including: Obtaining the intermediate point; Calculate the distance between each two intermediate points and sort them from small to large; Generate a path between the intermediate points according to a greedy rule; Determining whether the number of switching times of the path reaches a preset threshold; When the number of exchanges reaches a preset threshold, saving the current path between the intermediate points as the inspection route; When the number of exchanges does not reach a preset threshold, the path segments in the path are exchanged, and the exchanged path is calculated; determining whether the length of the path decreases; In the case where the length of the path is reduced, the exchanged path is used as a new path, and the process returns to the step of determining whether the number of exchanges of the path reaches a preset threshold; In the case that the length of the path is not reduced, the process returns to the step of determining whether the number of exchanges of the path reaches a preset threshold.

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