A Path Planning Method for Cable Cruise Monitoring of Unmanned Aerial Vehicles

Abstract

The present invention discloses a method for path planning of cable cruise monitoring by an unmanned aerial vehicle. According to the distribution of power grid cables, the positions of obstacles and cable towers are marked and cylindrical piles are set on the computer map. The maximum cruise range, maximum cruise time and extreme environment discrimination parameters of the unmanned aerial vehicle cruise are determined. The three-dimensional coordinates are recorded with the center of the circular surface of the cylindrical pile of the cable tower. The number of cable towers within the cruise monitoring path range is determined. At the same time, a three-dimensional cruise route L is generated. According to different unmanned aerial vehicle models, the safety monitoring distance and the height deviation during the actual flight of the unmanned aerial vehicle are set to form a new cruise route Lp. Under the preset value of the unmanned aerial vehicle constraint conditions, the cruise path planning is carried out to make the cable cruise monitoring path applicable to various different cruise environments, improve the cruise efficiency, conduct real-time damage degree evaluation on the cables, reduce the misjudgment caused by manual detection, reduce resource waste, and improve the work efficiency of maintenance personnel.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and particularly to a method for planning a cruise monitoring path of an unmanned aerial vehicle cable. Background Art

[0002] With the development of intelligent devices, unmanned aerial vehicle technology has been widely used in various fields of daily production, such as aerial photography, agriculture, express delivery, disaster relief, wildlife observation, infectious disease monitoring, surveying and mapping, news reporting, power line inspection, disaster relief, film and television shooting, and many other fields.

[0003] Cable power supply is the most common power supply means in modern life. However, the inspection of cable wear is time-consuming and laborious, and many subtle cable abnormalities are not easily detected by operators. Therefore, using the aerial camera of an unmanned aerial vehicle to conduct cruise monitoring of cable lines and planning the cruise path has great significance for the maintenance of cable lines.

[0004] In addition, in actual application scenarios, the endurance time of unmanned aerial vehicles is often limited by battery technology. To enable unmanned aerial vehicles to cruise automatically for a long time, automatic charging devices are usually set at a certain fixed position. When the battery power of the unmanned aerial vehicle is insufficient, it returns to the automatic charging device for charging and continues to cruise after the charging is completed, extending the working time of the unmanned aerial vehicle. However, in the prior art, since the unmanned aerial vehicle needs to return to the automatic charging device for charging, the unmanned aerial vehicle can only cruise within a certain range centered on the automatic charging device, restricting the cruise range of the unmanned aerial vehicle.

[0005] For example, a "method for planning an unmanned aerial vehicle path" disclosed in a Chinese patent document with the publication number CN112327907A has the problem that the unmanned aerial vehicle needs to return to the automatic charging device for charging, resulting in the unmanned aerial vehicle being able to only cruise within a certain range centered on the automatic charging device, restricting the cruise range of the unmanned aerial vehicle. Summary of the Invention

[0006] The present invention is to overcome the problems in the prior art that it is impossible to reasonably use the aerial camera of an unmanned aerial vehicle to conduct cruise monitoring of cable lines and plan the cruise path, and the unmanned aerial vehicle is limited by battery technology and has a very limited endurance time, and provides a method for planning a cruise monitoring path of an unmanned aerial vehicle cable.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for planning a cruise monitoring path of an unmanned aerial vehicle cable includes the following steps:

[0009] Step SA1: Record the distribution of the power grid cables, upload the position coordinates of all obstacles and cable towers to the on-board computer of the UAV, and set cylindrical piles on the map of the on-board computer of the UAV to wrap the obstacles and cable towers;

[0010] Step SA2: Determine the cruise constraint conditions of the UAV and the constraint conditions of the UAV's endurance, that is, determine the maximum cruise range lmax, the maximum cruise time tmax and the extreme environment discrimination parameter Tex;

[0011] Step SA3: According to the constraint conditions in Step SA2, record the three-dimensional coordinates as (xi, yi, zi) with the center of the circular surface of the cylindrical pile of the cable tower, and record the two-dimensional plane coordinates as (xj, yj, zj) with the center of the circular surface of the cylindrical pile of the obstacle. Among them, xi is the longitude of the i-th tower, yi is the latitude of the i-th tower, and zi is the horizontal height of the top of the i-th tower;

[0012] Step SA4: According to the two-dimensional coordinates (xi, yi, zi) of the cable tower obtained in Step S2, determine the number of cable towers i (i = 1, 2, 3,... n) within the cruise monitoring path range, and at the same time generate a three-dimensional cruise route L (x1, y1, z1, x2, y2, z2, x3, y3, z3,... xn, yn, zn). The cruise route L is generated according to the following logic: starting from the tower with coordinates (x1, y1, z1), the tower closest to (x1, y1, z1) is marked as (x2, y2, z2), the tower closest to (x2, y2, z2) is marked as (x3, y3, z3), and so on. The tower closest to (xn-1, yn-1, zn-1) is marked as (xn, yn, zn), and any tower is only marked once during the marking process;

[0013] Step SA5: According to different UAV models, set the safety monitoring distance as a and the height deviation during the actual flight of the UAV as b, and add a and b to the cruise route L to form a new cruise route Lp (x1, y1 + a + b, z1, x2, y2 + a + b, z2, x3, y3 + a + b, z3,... xn, yn + a + b, zn), and use Lp as the actual cruise monitoring route.

[0014] In the above process, before the UAV conducts cruise monitoring of the planned path, preset the constraint conditions of the UAV, including the following content:

[0015] A. Assume that the UAV flies along the feasible shortest path between each node, the shortest path remains unchanged in the entire road network planning, and the accurate shortest path distance can be obtained before path planning;

[0016] B. Assume that the UAV cruises at a specified cruising speed and altitude, and the endurance time and cruising distance are fixed and unchanged;

[0017] C. Before path planning, obtain the positions, shapes, and distribution states of each cable tower column;

[0018] D. Conduct environmental detection before path planning to determine the influence range and degree of extreme environments on the flight time, flight space, and flight state of the UAV.

[0019] Obtain the maximum cruising range lmax and maximum cruising time tmax of the UAV in a normal environment through the shortest path distance; as well as the extreme environment threshold Tex and the maximum cruising range lmax and maximum cruising time tmax in an extreme environment state; and then better set the cruising path of the UAV and the charging threshold of the UAV separately for the normal state and the extreme environment state, and intelligently adjust the working time and cruising path planning of the UAV.

[0020] Preferably, the path planning method further includes the coordinate planning of the UAV charging base point, including the following steps:

[0021] Step SB1: Obtain the tower pole coordinate data recorded in step SA3 and step SA4;

[0022] Step SB2: According to the coordinates of the three points (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3), connect the three positions pairwise to form a triangular area, and set the UAV charging base point at the centroid position of this triangular area, and its coordinates are P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3);

[0023] Step SB3: Set the last coordinate point of the triangular area of each base point as the initial coordinate point of the next triangular area, that is, P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3), P2((x3 + x4 + x5) / 3, (y3 + y4 + y5) / 3, (z3 + z4 + z5) / 3)…, Pn((x2n - 1 + x2n + x2n + 1) / 3, (y2n - 1 + y2n + y2n + 1) / 3, (z2n - 1 + z2n + z2n + 1) / 3).

[0024] Set a triangular area based on the coordinates of three cable tower poles, and use the centroid of this triangular area as the charging base point coordinates, reduce the path for the UAV to return to the base point for charging when reaching the charging threshold, improve the cruising efficiency of the UAV, and reduce resource waste.

[0025] Preferably, the base point also includes a UAV cruise control device, which collects the current power of the UAV and receives cable damage status data from the UAV in real time, and issues instructions for the UAV to continue its flight or return to charge.

[0026] Preferably, during the cruising process, the drone receives a control signal sent by a base point of the current triangular area. When the drone is low on power or receives an emergency rerouting signal sent by a base point, it returns to the base point in the triangular area for charging or new route data and resumes cruising.

[0027] Preferably, the drone includes a base point ranging module, which calculates in real time the distance between the current drone position and the base points in the current triangular area and the base points in the adjacent triangular areas. When the drone is at a cable tower and receives a return signal sent by the base point, the base point closest to the current drone position is selected for the return operation.

[0028] Plan the distances between charging points and cruise paths to reduce the charging distance of drones during intelligent cruise, improve the cruise efficiency of drones, and reduce the impact on efficiency caused by the limited battery technology and limited flight time of drones.

[0029] Preferably, the detected data of the cable by the drone includes the downward curvature of the cable, the reflectivity of the cable surface and the surface temperature of the cable in the current power-on state.

[0030] Preferably, the real-time cable detection data collected by the drone is sent back to the base station for weighted numerical scoring. When the numerical score reaches a damage threshold, the drone sends the coordinates of two cable towers adjacent to the cable to the maintenance center, marks the cable, and records the number of repairs and the maintenance status of each cable.

[0031] The camera on the drone is used to detect the cable in real time and record the current physical state of the cable. The downward curvature of the cable, the reflectivity of the rubber surface and the surface temperature of the cable are evaluated by a weighted comprehensive scoring system to obtain a damage score. This score is then compared with the preset damage threshold score to quickly provide feedback on the damage state of the detected cable during the cruise process, and send the damage location and degree to the maintenance personnel, reducing misjudgments caused by manual inspections, thereby reducing resource waste and improving the work efficiency of maintenance personnel.

[0032] Therefore, the beneficial effects of the present invention are as follows:

[0033] Under the preset values ​​of the UAV constraint conditions, the cruise path planning is carried out to make the cable cruise monitoring path suitable for various cruise environments and improve the cruise efficiency;

[0034] Divide the coordinates of the cable towers into points to divide the triangular areas, and use the centroid of the triangular areas as the charging and signal base points to improve the charging and information interaction efficiency of the UAV, and reduce the endurance impact caused by the very limited endurance time of the UAV due to the limitation of battery technology;

[0035] Evaluate the real-time damage degree of the cable, have accurate data reference and positioning for the damage degree of the cable, reduce the misjudgment caused by manual detection, reduce resource waste, and improve the work efficiency of maintenance personnel. Description of the Drawings

[0036] Figure 1 is the flowchart for establishing the cruise route planning model of the present invention;

[0037] Figure 2 is the flowchart for planning the charging base point position of the UAV of the present invention;

[0038] Figure 3 is the schematic diagram for planning the charging and signal base point positions of the present invention. Detailed Embodiment

[0039] The present invention will be further specifically described below in conjunction with the drawings and detailed embodiments.

[0040] As Figure 1 shown, a method for planning the cruise monitoring path of a UAV for a cable includes the following steps:

[0041] Step SA1: Record the distribution of the power grid cables, upload the position coordinates of all obstacles and cable towers to the on-board computer of the UAV, and set cylindrical piles on the map of the on-board computer of the UAV to wrap the obstacles and cable towers;

[0042] Step SA2: Determine the cruise constraint conditions of the UAV and the constraint conditions of the UAV endurance ability, that is, determine the maximum cruise range lmax, the maximum cruise time tmax and the extreme environment discrimination parameter Tex of the UAV;

[0043] Step SA3: According to the constraint conditions in Step SA2, record the three-dimensional coordinates as (xi, yi, zi) with the center of the circular surface of the cylindrical pile of the cable tower, and record the plane two-dimensional coordinates as (xj, yj, zj) with the center of the circular surface of the cylindrical pile of the obstacle, where xi is the longitude of the i-th tower, yi is the latitude of the i-th tower, and zi is the horizontal height of the top of the i-th tower;

[0044] Step SA4: According to the two-dimensional coordinates (xi, yi, zi) of the cable towers obtained in Step S2, determine the number i (i = 1, 2, 3, … n) of cable towers within the range of the cruise monitoring path, and simultaneously generate a three-dimensional cruise route L (x1, y1, z1, x2, y2, z2, x3, y3, z3, … xn, yn, zn). The cruise route L is generated according to the following logic: starting from the tower with coordinates (x1, y1, z1), the tower closest to (x1, y1, z1) is marked as (x2, y2, z2), the tower closest to (x2, y2, z2) is marked as (x3, y3, z3), and so on. The tower closest to (xn-1, yn-1, zn-1) is marked as (xn, yn, zn), where any tower is only marked once during the marking process;

[0045] Step SA5: Set the safety monitoring distance as a and the height deviation during the actual flight of the drone as b according to different drone models, and add a and b to the cruise route L to form a new cruise route Lp (x1, y1 + a + b, z1, x2, y2 + a + b, z2, x3, y3 + a + b, z3, … xn, yn + a + b, zn), and use Lp as the actual cruise monitoring route.

[0046] In the above process, before the drone conducts cruise monitoring of the planned path, preset the default values of the drone constraint conditions, including the following:

[0047] A. Assume that the drone flies along the feasible shortest path between nodes, the shortest path remains unchanged in the entire road network planning, and the accurate shortest path distance can be obtained before path planning;

[0048] B. Assume that the drone conducts cruise flight at a specified cruise speed and cruise altitude, and the endurance time and the number of cruise distances are fixed;

[0049] C. Before path planning, obtain the position, shape and distribution status of each cable tower column;

[0050] D. Conduct environmental detection before path planning to determine the influence range and influence degree of extreme environments on the flight time, flight space and flight state of the drone.

[0051] Obtain the maximum cruise range lmax and maximum cruise time tmax of the drone in normal environments through the shortest path distance; as well as the extreme environment threshold Tex and the maximum cruise range lmax and maximum cruise time tmax in extreme environment states; and then better set the cruise path of the drone and the charging threshold of the drone for normal and extreme environment states respectively, and intelligently adjust the working time and cruise path planning of the drone.

[0052] AsFigure 2 As shown, the path planning method further includes the coordinate planning of the UAV charging base point, which includes the following steps:

[0053] Step SB1: Obtain the tower pole coordinate data recorded in step SA3 and step SA4;

[0054] Step SB2: According to the coordinates of the three points (x1, y1, z1), (x2, y2, z2) and (x3, y3, z3), connect the three positions in pairs to form a triangular area. At the centroid position of this triangular area, set the UAV charging base point, and its coordinates are P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3);

[0055] Step SB3: Set the last coordinate point of the triangular area of each base point as the initial coordinate point of the next triangular area, that is, P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3), P2((x3 + x4 + x5) / 3, (y3 + y4 + y5) / 3, (z3 + z4 + z5) / 3)…, Pn((x2n - 1 + x2n + x2n + 1) / 3, (y2n - 1 + y2n + y2n + 1) / 3, (z2n - 1 + z2n + z2n + 1) / 3).

[0056] Based on the coordinates of three cable tower poles, set a triangular area, and use the centroid of this triangular area as the charging base point coordinates, which can reduce the path for the UAV to return to the base point for charging when it reaches the charging threshold, improve the cruising efficiency of the UAV, and reduce resource waste.

[0057] The base point also includes a UAV cruise control device, which can collect the current power of the UAV in real time and receive the cable damage status data received by the UAV, and issue instructions for the UAV to continue cruising or return for charging.

[0058] During the UAV cruise, receive the control signal sent by the base point of the current triangular area. When the UAV's power is insufficient or receives the emergency course change signal sent by the base point, return to the base point within the triangular area for charging or new route data, and resume cruising.

[0059] The UAV includes a base point ranging module, which can calculate the distances between the current UAV position and the base points in the current triangular area and the base points in adjacent triangular areas in real time. When the UAV receives the return signal sent by the base point at the cable tower pole, select the base point closest to the current UAV position for the return operation.

[0060] Plan the distances between charging points and cruise paths to reduce the charging distance of drones during intelligent cruise, improve the cruise efficiency of drones, and reduce the impact on efficiency caused by the limited battery technology and limited flight time of drones.

[0061] The detection data of the cable by the drone includes the downward curvature of the cable, the reflectivity of the cable surface and the surface temperature of the cable in the current power-on state.

[0062] The real-time cable detection data collected by the drone is sent back to the base station for weighted numerical scoring. When the numerical score reaches the damage threshold, the drone sends the coordinates of the two cable towers adjacent to the cable to the maintenance center, marks the cable, and records the number of repairs and maintenance status of each cable.

[0063] The camera on the drone is used to detect the cable in real time and record the current physical state of the cable. The downward curvature of the cable, the reflectivity of the rubber surface and the surface temperature of the cable are evaluated by a weighted comprehensive scoring system to obtain a damage score. This score is then compared with the preset damage threshold score to quickly provide feedback on the damage state of the detected cable during the cruise process, and send the damage location and degree to the maintenance personnel, reducing misjudgments caused by manual inspections, thereby reducing resource waste and improving the work efficiency of maintenance personnel.

[0064] In the above detection and evaluation of the physical state of the cable, the rated threshold or permanent threshold of each detection value is set. When the deviation from the rated threshold is within 20%, the built-in data anomaly score increases by 1 for every 0.5% increase; when the deviation from the current set threshold is 20%-35%, the built-in data anomaly score increases by 1 for every 0.25% increase; when the deviation from the current set threshold exceeds 35%, the data anomaly signal is directly sent to the risk assessment module through the communication module for risk assessment. When the data anomaly score is within 30, the risk assessment is "not serious" and recorded as a D-level fault; when the data anomaly score is between 30-50, the risk assessment is "relatively serious" and recorded as a C-level fault; when the data anomaly score is between 50-75, the risk assessment is "serious" and recorded as a B-level fault; when the data anomaly score exceeds 75 or the current data deviates from the set threshold by more than 35%, the risk assessment is "very serious" and recorded as an A-level fault; while scoring the data anomaly, the location where the current data collection anomaly occurs is also recorded, and the location where the anomaly occurs is divided into important levels.

[0065] By comprehensively judging the degree of data abnormality and the location where it occurs, the data abnormality situation is divided into 8 levels. While carrying out alarm processing, the above-mentioned fault levels and fault records are recorded in historical data. The drone sends this data to the charging base station in real time, and the data is replaced every month. The maximum data storage period is one year, which is convenient for subsequent division of vulnerable areas and reduces the workload of maintenance staff.

[0066] The above has described in detail the structure, features and function effects of the present invention according to the illustrated embodiments. However, the above are only the preferred embodiments of the present invention. It should be noted that for the technical features involved in the above embodiments and their preferred modes, those skilled in the art can reasonably combine and match them into a variety of equivalent solutions without departing from and changing the design concept and technical effects of the present invention. Therefore, the scope of implementation of the present invention is not limited by the drawings shown. Any changes made in accordance with the concept of the present invention, or modified into equivalent embodiments with equivalent changes, should still be within the protection scope of the present invention as long as they do not exceed the spirit covered by the description and the drawings.

Claims

1. A method for path planning of cable cruise monitoring of an unmanned aerial vehicle, characterized in that, including the following steps Step SA1: Record the distribution of power grid cables, upload the position coordinates of all obstacles and cable towers to the on-board computer of the drone, and set cylindrical piles on the map of the on-board computer of the drone to wrap the obstacles and cable towers; Step SA2: Determine the maximum cruising range lmax, maximum cruising time tmax and extreme environment discrimination parameter Tex of the drone; Step SA3: According to the constraints in Step SA2, record the three-dimensional coordinates as (xi, yi, zi) with the center of the circular surface of the cylindrical pile of the cable tower, and record the two-dimensional plane coordinates as (xj, yj, zj) with the center of the circular surface of the cylindrical pile of the obstacle, where xi is the longitude of the i-th tower, yi is the latitude of the i-th tower, and zi is the horizontal height of the top of the i-th tower; Step SA4: According to the two-dimensional coordinates (xi, yi, zi) of the cable towers obtained in Step S2, determine the number i of cable towers within the cruising monitoring path range, and at the same time generate a three-dimensional cruising route L(x1, y1, z1, x2, y2, z2, x3, y3, z3,... xn, yn, zn). The cruising route L is generated according to the following logic: starting from the tower with coordinates (x1, y1, z1), the tower closest to (x1, y1, z1) is marked as (x2, y2, z2), the tower closest to (x2, y2, z2) is marked as (x3, y3, z3), and so on. The tower closest to (xn-1, yn-1, zn-1) is marked as (xn, yn, zn), and any one tower is only marked once during the marking process; Step SA5: According to different drone models, set the safety monitoring distance as a and the height deviation during the actual flight of the drone as b, and add a and b to the cruising route L to form a new cruising route Lp(x1, y1+a+b, z1, x2, y2+a+b, z2, x3, y3+a+b, z3,... xn, yn+a+b, zn), and use Lp as the actual cruising monitoring route; Step SA6: Obtain the tower coordinate data recorded in Step SA3 and Step SA4, generate charging base points based on the coordinates of three consecutive towers, and use the centroid of the triangular area formed by every three adjacent tower coordinates as the base point coordinates, and its coordinates are P1((x1+x2+x3) / 3, (y1+y2+y3) / 3, (z1+z2+z3) / 3), and the last coordinate point of each triangle is used as the starting point of the next triangle, that is, P1((x1+x2+x3) / 3, (y1+y2+y3) / 3, (z1+z2+z3) / 3), P2((x3+x4+x5) / 3, (y3+y4+y5) / 3, (z3+z4+z5) / 3)..., Pn((x2n-1+x2n+x2n+1) / 3, (y2n-1+y2n+y2n+1) / 3, (z2n-1+z2n+z2n+1) / 3).

2. The method for planning the cruise monitoring path of the UAV cable according to claim 1, characterized in that, The path planning method also includes the coordinate planning of the charging base points of the drone, including the following steps: Step SB1: Obtain the tower pole coordinate data recorded in Step SA3 and Step SA4; Step SB2: According to the coordinates of the three points (x1, y1, z1), (x2, y2, z2) and (x3, y3, z3), connect the three positions in pairs to form a triangular area. At the centroid position of this triangular area, set the UAV charging base point, and its coordinates are P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3); Step SB3: Set the last coordinate point of the triangular area of each base point as the initial coordinate point of the next triangular area, that is, P1((x1 + x2 + x3) / 3, (y1 + y2 + y3) / 3, (z1 + z2 + z3) / 3), P2((x3 + x4 + x5) / 3, (y3 + y4 + y5) / 3, (z3 + z4 + z5) / 3)…, Pn((x2n - 1 + x2n + x2n + 1) / 3, (y2n - 1 + y2n + y2n + 1) / 3, (z2n - 1 + z2n + z2n + 1) / 3).

3. A method for path planning of drone cable cruise monitoring according to claim 1 or 2, characterized in that, The base point also includes a UAV cruise control device, which collects the current power of the UAV in real time and receives the cable damage status data received by the UAV, and issues instructions for the UAV to continue cruising or return for charging.

4. A method for path planning of cable cruise monitoring of an unmanned aerial vehicle according to claim 3, characterized in that, During the UAV cruise, it receives the control signal sent by the base point of the current triangular area. When the UAV's power is insufficient or it receives the emergency course change signal sent by the base point, it returns to the base point in the triangular area for charging or new route data, and resumes cruising.

5. A method for planning a cruise monitoring path of a drone cable, according to claim 2 or 3 or 4, characterized in that The UAV includes a base point ranging module, which calculates the distances between the current UAV position and the base points in the current triangular area and the base points in the adjacent triangular areas in real time. When the UAV receives the return signal sent by the base point at the cable tower pole, it selects the base point closest to the current UAV position for the return operation.

6. The method for path planning of cable cruise monitoring of an unmanned aerial vehicle according to claim 1, characterized in that, The data detected by the UAV for the cable includes the downward curvature of the cable, the reflectivity of the cable surface, and the surface temperature of the cable under the current energized state.

7. A method for path planning of cable cruise monitoring of an unmanned aerial vehicle according to claim 4 or 6, characterized in that, The detected data of the real-time cable collected by the UAV is sent back to the base station for weighted numerical scoring. When the numerical score reaches the damage threshold, the UAV sends the coordinates of the two cable tower poles adjacent to this cable to the maintenance center, marks this cable, and records the repair times and repair conditions of each cable; in the detection and evaluation of the physical state of the cable, set the rated threshold or permanent threshold of each detection value for risk assessment.

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