A tree obstacle early warning method for power transmission channels based on UAV laser radar

Abstract

The invention relates to a tree barrier early warning method for a power transmission channel based on a UAV laser radar. A catenary curve model is established for a cable so that a line patrol UAV flies along a route and detects the height of the lower front cable at the same time. When the height differs greatly from a calculated result, a tree barrier early warning is issued and the vehicle flies around. When flying around, a laser radar is used to transmit a radar signal to the tree barrier. When the echo measurement height is consistent with the curve model, it is proved that the cable can be reached through the gap. At this time, an optical image is obtained by an optical lens to complete the line patrol at the tree barrier. The invention can enable the line patrol UAV to effectively avoid the tree barrier of the overhead cable and complete the line patrol of the cable in the tree barrier as much as possible.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) line patrol, and in particular to a tree obstacle early warning method for a power transmission channel based on an unmanned aerial vehicle (UAV) laser radar. Background Art

[0002] Lidar is a radar system that emits laser beams to detect the position, speed and other characteristic quantities of a target. Its working principle is to emit a detection signal (laser beam) to the target, and then compare the received signal reflected from the target (target echo) with the transmitted signal. After appropriate processing, relevant information about the target can be obtained, such as target distance, direction, height, speed, attitude, and even shape parameters, which can be used in line patrol operations to detect and identify obstacles.

[0003] During existing UAV line inspections, they are often disturbed by trees and bushes, which not only poses a danger to the UAVs, but also interferes with the capture of images of the cables. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a tree barrier warning method for a power transmission channel based on a UAV laser radar, which can warn of tree barriers in the UAV route during the line inspection process, and at the same time help the line inspection UAV to photograph parts of the cables blocked by the tree barriers.

[0005] The present invention provides a power transmission channel tree obstacle early warning method based on unmanned aerial vehicle laser radar, comprising the steps of:

[0006] The cable parameters are obtained by using a line inspection drone, and a curve model of the cable is established according to the cable parameters and the catenary equation. A route is made according to the curve model, and the route is located directly above the curve model and parallel to the curve model.

[0007] Use a line inspection drone to inspect the cables. The camera at the bottom of the drone takes optical images. The laser radar at the bottom of the drone sends laser signals forward and downward, and determines the height of the cables below and in front of the drone based on the echo signals.

[0008] The cable heights directly below the line-patrolling drone are modeled and compared with the curve model. Based on the comparison results, it is determined whether there are tree obstacles around the cables.

[0009] If it is determined that there is a tree obstacle, the line inspection drone adjusts its route when it flies to the tree obstacle and flies over the tree obstacle. At the same time, the line inspection drone circles the tree obstacle and turns the laser radar to send a laser signal to the tree obstacle. If the echo detects a cable that is consistent with the curve model, the camera is turned to take an optical image.

[0010] The patrol drone that passes the tree barrier returns to the route and continues patrolling until the end of the route.

[0011] Furthermore, the required parameters of the curve model are the sag and the height of the cable suspension points at both ends. The cable suspension point height is directly measured by a line patrol drone. The sag calculation formula is:

[0012]

[0013] Among them, l is the span, f is the sag, h is the height difference between the two poles, θ is the observation angle, a is the vertical distance from the suspension point to the laser radar, and α is the height difference angle;

[0014] The above formula obtains the maximum sag f1 and the minimum sag f2, which are substituted into the catenary equation:

[0015]

[0016] a' is a constant.

[0017] Furthermore, a distance sensor is provided at the bottom of the line-patrol UAV facing downward, and the distance sensor is connected to the flight control system of the line-patrol UAV. When the line-patrol UAV is navigating on a route or over a tree barrier, the distance sensor is used to keep the line-patrol UAV at a specific distance from the cable or tree barrier surface.

[0018] Furthermore, when the cable height measured by the laser radar differs from the height of the corresponding point in the curve model by no more than ±3%, the cable segment is deemed to be obstacle-free, and the line patrol drone flies over the cable segment according to the predetermined route; otherwise, it flies over the cable segment at a flight altitude that is the measured height plus a specific height.

[0019] Furthermore, the laser radar is installed in front of the bottom of the line patrol drone and is set at 45° directly downward.

[0020] The beneficial effects of the present invention are as follows: a tree barrier warning method for a power transmission channel based on a UAV laser radar of the present invention establishes a catenary curve model for the cable, so that the line patrol UAV flies along the route, and at the same time detects the height of the lower front cable. When the height differs greatly from the calculated result, a tree barrier warning is issued and the drone flies around. At the same time, the laser radar is used to transmit a radar signal to the tree barrier during the circumvention. When the echo measurement height is consistent with the curve model, it proves that the cable can be reached through the gap. At this time, an optical image is obtained by an optical lens to complete the line patrol at the tree barrier. The present invention can enable the line patrol UAV to effectively avoid the tree barrier of the overhead cable, and at the same time complete the line patrol of the cables in the tree barrier as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative work:

[0022] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0025] like Figure 1 As shown: A tree obstacle warning method for a power transmission channel based on a UAV laser radar in this embodiment includes the following steps:

[0026] Use the line patrol drone to obtain the cable parameters, and establish the cable curve model according to the cable parameters and the catenary equation. The parameters that need to be collected by the line patrol drone include the height difference h and the span L (i.e., the horizontal distance between the suspension points) at both ends of the cable. Both can be measured using the laser radar, altitude sensor and other measuring instruments on the line patrol drone. A route is made according to the curve model. The route is located directly above the curve model and is parallel to the curve model, that is, the line patrol drone flies directly above the cable at a constant altitude.

[0027] Use a line inspection drone to inspect the cables. The camera at the bottom of the drone takes optical images. The laser radar at the bottom of the drone sends laser signals to the front and bottom, and determines the height of the cable in front of and below the drone based on the echo signal. The drone's own height is measured by an altitude sensor and is known. The distance between the drone and the corresponding point of the cable is measured by the echo. The angle of the laser signal is consistent, so the height difference and horizontal distance between the drone and the measurement point can be calculated by trigonometric functions, and then compared with the model data by corresponding to the curve model.

[0028] The cable heights directly below the line-patrolling drone are modeled and compared with the curve model. Based on the comparison results, it is determined whether there are tree obstacles around the cables.

[0029] If it is determined that there is a tree obstacle, the line inspection drone adjusts its route when it flies to the tree obstacle and flies over the tree obstacle. At the same time, the line inspection drone circles the tree obstacle and turns the laser radar to send a laser signal to the tree obstacle. If the echo detects a cable that is consistent with the curve model, the camera is turned to take an optical image.

[0030] The patrol drone that passes the tree barrier returns to the route and continues patrolling until the end of the route.

[0031] In this embodiment, the required parameters of the curve model are the sag and the height of the cable suspension points at both ends. The cable suspension point height is directly measured by a line patrol drone. The sag calculation formula is:

[0032]

[0033] Wherein, l is the span, f is the sag, h is the height difference between the two poles, θ is the observation angle, a is the vertical distance from the suspension point to the laser radar, and α is the height difference angle; the sag formula is an existing technology, so it is not repeated;

[0034] The above formula obtains the maximum sag f1 and the minimum sag f2, which are substituted into the catenary equation:

[0035]

[0036] a' is a constant, constant a' = horizontal tension / line density, which can be obtained by referring to the data during cable laying.

[0037] In this embodiment, a distance sensor is provided at the bottom of the line patrol drone facing downward, and the distance sensor is connected to the flight control system of the line patrol drone. When the line patrol drone is navigating on a route or crossing a tree barrier, the distance sensor is used to keep the line patrol drone at a specific distance from the cable or tree barrier surface.

[0038] In this embodiment, when the cable height measured by the laser radar differs from the height of the corresponding point in the curve model by no more than ±3%, the cable segment is deemed to be obstacle-free. When the line patrol drone flies over the cable segment, it navigates according to the predetermined route. Otherwise, it flies over the cable segment at a flight altitude that is the measured height plus a specific height.

[0039] In this embodiment, the laser radar is installed in front of the bottom of the line patrol drone and is set at 45° directly downward. The distance between the laser radar and the cable is 1 / 2 of the detection distance.

[0040] The present invention discloses a power transmission channel tree barrier early warning method based on UAV laser radar. By establishing a catenary curve model for the cable, the line patrol UAV flies along the route and detects the height of the lower front cable at the same time. When the height differs greatly from the calculated result, a tree barrier early warning is issued and the drone flies around. At the same time, the laser radar is used to transmit a radar signal to the tree barrier during the flyaround. When the echo measurement height is consistent with the curve model, it is proved that the cable can be reached through the gap. At this time, an optical image is obtained by an optical lens to complete the line patrol at the tree barrier. The present invention can enable the line patrol UAV to effectively avoid the tree barrier of the overhead cable and complete the line patrol of the cables in the tree barrier as much as possible.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A tree obstacle early warning method for power transmission channels based on UAV laser radar, characterized in that: Includes steps: The cable parameters are obtained by using a line inspection drone, and a curve model of the cable is established according to the cable parameters and the catenary equation. A route is made according to the curve model, and the route is located directly above the curve model and parallel to the curve model. Use a line inspection drone to inspect the cables. The camera at the bottom of the drone takes optical images. The laser radar at the bottom of the drone sends laser signals forward and downward, and determines the height of the cables below and in front of the drone based on the echo signals. The cable heights directly below the line-patrolling drone are modeled and compared with the curve model. Based on the comparison results, it is determined whether there are tree obstacles around the cables. If it is determined that there is a tree obstacle, the line inspection drone adjusts its route when it flies to the tree obstacle and flies over the tree obstacle. At the same time, the line inspection drone circles the tree obstacle and turns the laser radar to send a laser signal to the tree obstacle. If the echo detects a cable that is consistent with the curve model, the camera is turned to take an optical image. The patrol drone that has passed the tree barrier returns to the route and continues patrolling until the end of the route; The required parameters of the curve model are the sag and the height of the cable suspension points at both ends. The cable suspension point height is directly measured by a line patrol drone. The sag calculation formula is: Among them, l is the span, f is the sag, h is the height difference between the two poles, θ is the observation angle, a is the vertical distance from the suspension point to the laser radar, and α is the height difference angle; The above formula obtains the maximum sag f1 and the minimum sag f2, which are substituted into the catenary equation: Where a' is a constant.

2. The tree obstacle early warning method for power transmission channel based on UAV laser radar according to claim 1 is characterized by: A distance sensor facing downward is provided at the bottom of the line patrol drone, and the distance sensor is connected to the flight control system of the line patrol drone. When the line patrol drone is navigating on a route or over a tree barrier, the distance sensor is used to keep the line patrol drone at a specific distance from the cable or tree barrier surface.

3. The tree obstacle early warning method for power transmission channel based on UAV laser radar according to claim 1 is characterized by: When the cable height measured by the laser radar differs from the height of the corresponding point in the curve model by no more than ±3%, the cable segment is deemed to be obstacle-free. When the line patrol drone flies over the cable segment, it navigates according to the predetermined route. Otherwise, it flies over the cable segment at a flight altitude that is the measured height plus a specific height.

4. The tree obstacle early warning method for power transmission channel based on UAV laser radar according to claim 1 is characterized by: The laser radar is installed in front of the bottom of the line patrol drone and is set at 45° directly downward.

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