An accurate method for measuring the sag of overhead lines by an unmanned aerial vehicle based on a coaxial dual coordinate system

Abstract

The present invention discloses a method for accurately measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial double coordinate system, which includes establishing a two-dimensional coordinate system plane with two adjacent iron towers, taking any one of the bases of the two adjacent iron towers and the conductor suspension point as the origin of the rectangular coordinate system, establishing a coaxial double rectangular coordinate system, establishing a rectangular coordinate system x'o'y' with the original coordinate origin of the conductor suspension point, and establishing a rectangular coordinate system xoy with the base of the iron tower as the coordinate origin. A coaxial double rectangular coordinate system xoy and x'o'y' is established by using the conductor suspension point and the base of the iron tower of any one of the two adjacent iron towers as the coordinate origin, and the coordinates (x1y1) of the unmanned aerial vehicle are obtained by using the lidar carried by the unmanned aerial vehicle, and the polar coordinates of any point on the conductor relative to the unmanned aerial vehicle are (ρθ). They are respectively substituted into the coaxial double rectangular coordinate systems xoy and x'o'y' to obtain the vertical distance from the sag measurement point to the unmanned aerial vehicle and the vertical distance from the sag measurement point to the straight line equation established relative to the conductor suspension point, so as to obtain the sag.

Description

Technical Field

[0001] The present invention relates to a method for measuring the sag of a wire, specifically a method for real-time and accurately measuring the sag of a wire by using an unmanned aerial vehicle (UAV) RTK technology based on a coaxial double rectangular coordinate system, and belongs to the technical field of tensioning construction of overhead transmission lines. Background Art

[0002] When the transmission distance is relatively long, due to the self-weight of the wire, a slight sag will be formed, making the wire in the shape of a catenary. And the sag of the transmission line is a main index for line design and operation, which is related to the operation safety of the line. Therefore, it must be controlled within the range specified by the design.

[0003] Since the changes in the line operation load and the surrounding environment will both cause changes in the line sag, an excessive sag will not only pose potential accident hazards but also limit the transmission capacity of the line, especially in the areas of crossing and densely populated areas. At present, the dynamic capacity increase technology has become the key to improving the power transmission capacity. There is a correlation between the sag of the power transmission wire and the transmission capacity of the wire, which also reflects the operation safety problem of the transmission wire. In recent years, due to the growth of the power consumption load, in order to improve the transmission capacity, the maximum allowable operating temperature of the wire of many existing transmission lines has been increased from 70 °C to 80 °C. At this time, the line sag has become the main limiting factor, and it is necessary to calibrate or monitor the sag in real time to ensure the safety of the line operation and the equipment being crossed.

[0004] In the prior art, the observation methods of the sag of the ground wire generally include the equal-length method, the unequal-length method, and the angle method. However, due to the defects such as the subjective error of the measurement personnel, the measurement risk, and the lag in issuing the measurement results in the traditional methods, in recent years, the domestic wire stringing construction has begun to vigorously explore the use of a real-time sag measurement system for the tensioning construction of transmission lines based on RTK positioning by using an unmanned aerial vehicle to replace the traditional manual observation method and improve the automation and intelligence level of sag measurement.

[0005] The commonly used methods for the UAV to measure the sag of the wire in real time are as follows: 1) A method for measuring the sag of a transmission line based on high-precision three-dimensional modeling of an unmanned aerial vehicle (Publication No.: CN114383553A); 2) A method for measuring the sag based on the carrier phase differential technology of an unmanned aerial vehicle for a transmission line (Publication No.: CN114543699A); 3) A wire sag measurement system based on RTK UAV point sampling curve fitting (Publication No.: CN114545469A); 4) A method for measuring the sag of a transmission line based on the laser point cloud model of an unmanned aerial vehicle (Publication No.: CN114396878A). In these four prior arts, the transmission wire is directly modeled, and the mathematical model of the wire is approximated as a parabola. However, the actual mathematical model of the wire is an irregular parabola, and the above technical solutions will all bring relatively large errors. Summary of the Invention

[0006] The object of the present invention is to provide a method for accurately measuring the sag of a conductor in real time using the UAV RTK technology based on a coaxial double rectangular coordinate system, so as to solve at least one of the above technical problems. The method uses a UAV to measure the sag of the conductor in real time, ensuring a safe distance between the transmission conductor and the ground, thereby ensuring the safe and effective operation of the transmission line.

[0007] The present invention achieves the above object through the following technical solutions: A method for accurately measuring the sag of a conductor by a UAV based on a coaxial double coordinate system, comprising the following steps

[0008] Step 1: Establish a two-dimensional coordinate system plane with two adjacent iron towers. Take any one of the bases and the conductor suspension points in the two adjacent iron towers as the origin of the rectangular coordinate system, and establish coaxial double rectangular coordinate systems x'o'y' and xoy;

[0009] Among them, the suspension point of Tower 1 is A, and the suspension point of Tower 2 is C;

[0010] Step 2: Place the ground base station at the coordinate origin O. The UAV carries the mobile base station and takes off into the span between adjacent iron towers. The UAV transmits its own coordinates (x1, y1) in real time. The UAV establishes a polar coordinate system with its own position as the coordinate origin, and obtains the coordinates of any point B on the conductor relative to the UAV as (ρ, θ);

[0011] Step 3: Obtain the height h2 and horizontal distance h3 of any point B relative to the UAV according to the polar coordinates of any point B, and then obtain the horizontal and vertical coordinates of any point B as (x, y);

[0012] Among them, h2 is the vertical distance of the measured sag point on the conductor relative to the UAV, and h3 is the horizontal distance of the measured sag point on the conductor relative to the UAV;

[0013] Step 4: In the x'o'y' rectangular coordinate system, the horizontal and vertical coordinates of the suspension point C are (d, H1 - H2). According to the horizontal and vertical coordinates of the suspension points A and C of Tower 1, establish the straight line equation of the two suspension points A and C;

[0014] Among them, H1 is the height from the suspension point of Tower 1 to the tower base, H2 is the height from the suspension point of Tower 2 to the tower base, and d is the span between adjacent iron towers;

[0015] Step 5: Substitute the abscissa of any point B into the straight line equation, and the ordinate h1 generated by substituting any point B into the straight line equation determined by the suspension point in the xoy coordinate system can be obtained;

[0016] Step 6: At this time, the sag at any point B on the conductor is:

[0017] h4 = h1 + H1 - h2 - y1

[0018] As a further solution of the present invention: in the first step, a coaxial double rectangular coordinate system x'o'y' is established with the wire suspension point as the coordinate origin, and a coaxial double rectangular coordinate system xoy is established with the tower base as the coordinate origin.

[0019] As a further solution of the present invention: in the second step, a lidar installed is used to scan any point B to determine the coordinates of any point B relative to the unmanned aerial vehicle.

[0020] As a further solution of the present invention: in the third step,

[0021] The obtained height h2 of the unmanned aerial vehicle is: h2 = ρsinθ

[0022] The obtained horizontal distance h3 is: h3 = ρcosθ

[0023] The obtained abscissa and ordinate (x, y) of any point B are:

[0024] x = x1 - cosθ

[0025] y = y1 - sinθ

[0026] As a further solution of the present invention: in the fourth step, the straight-line equation determined by the suspension points A and C is:

[0027]

[0028] As a further solution of the present invention: in the fifth step, the calculation formula of h1 is:

[0029]

[0030] where h1 is the ordinate generated by substituting the abscissa x = x1 - cosθ into the straight-line equation determined by the suspension points in the xoy coordinate system.

[0031] The beneficial effects of the present invention are as follows: the sag of the wire is measured in real time by using an unmanned aerial vehicle, and a coaxial double rectangular coordinate system xoy and x'o'y' are established. Moreover, the coordinates (x1, y1) of the unmanned aerial vehicle and the polar coordinates of any point on the wire relative to the unmanned aerial vehicle are (ρ, θ) obtained by using the lidar carried by the unmanned aerial vehicle. They are respectively substituted into the coaxial double rectangular coordinate systems xoy and x'o'y' to obtain the vertical distance from the sag measurement point to the unmanned aerial vehicle and the vertical distance from the sag measurement point to the straight-line equation established relative to the wire suspension point, so as to obtain the sag, making the measurement result more accurate, easy to operate, ensuring the safe distance between the transmission wire and the ground, and thus ensuring the safe and effective operation of the transmission line. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of adjacent towers and wire suspensions of the present invention;

[0033] Figure 2 This is the sag measurement model diagram of the present invention for the wire. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment 1

[0036] As Figures 1 to 2 shown, a method for accurately measuring the sag of a wire by an unmanned aerial vehicle based on a coaxial double coordinate system includes the following steps

[0037] Step 1: Establish a two-dimensional coordinate system plane with two adjacent iron towers. Take any one of the bases and the wire suspension points in the two adjacent iron towers as the origin of the rectangular coordinate system, and establish coaxial double rectangular coordinate systems x'o'y' and xoy;

[0038] Among them, the suspension point of Tower 1 is A, and the suspension point of Tower 2 is C;

[0039] Step 2: Place the ground base station at the coordinate origin O. The unmanned aerial vehicle carries the mobile base station and takes off into the span between adjacent iron towers. The unmanned aerial vehicle transmits its own coordinates (x1, y1) in real time. The unmanned aerial vehicle takes its own position as the origin of the coordinate system, establishes a polar coordinate system, and obtains the coordinates of any point B on the wire relative to the unmanned aerial vehicle as (ρ, θ);

[0040] Step 3: Obtain the height h2 and the horizontal distance h3 of any point B relative to the unmanned aerial vehicle according to the polar coordinates of any point B, and further obtain the horizontal and vertical coordinates of any point B as (x, y);

[0041] Among them, h2 is the vertical distance of the measured sag point on the wire relative to the unmanned aerial vehicle, and h3 is the horizontal distance of the measured sag point on the wire relative to the unmanned aerial vehicle;

[0042] Step 4: In the x'o'y' rectangular coordinate system, the horizontal and vertical coordinates of the suspension point C are (d, H1 - H2). According to the horizontal and vertical coordinates of the suspension point A and the suspension point C of Tower 1, establish the straight line equation of the two suspension points A and C;

[0043] Among them, H1 is the height from the suspension point of Tower 1 to the tower base, H2 is the height from the suspension point of Tower 2 to the tower base, and d is the span between adjacent iron towers;

[0044] Step 5: Substitute the abscissa of any point B into the linear equation, and the ordinate h1 generated by substituting any point B into the linear equation determined by the suspension points in the xoy coordinate system can be obtained.

[0045] Step 6: At this time, the sag at any point B on the wire is:

[0046] h4 = h1 + H1 - h2 - y1

[0047] In the embodiment of the present invention, in the said Step 1, the coaxial double rectangular coordinate system x'o'y' is established with the suspension point of the wire as the coordinate origin, and the coaxial double rectangular coordinate system xoy is established with the tower base as the coordinate origin.

[0048] In the embodiment of the present invention, in the said Step 2, a lidar is used to scan any point B to determine the coordinates of any point B relative to the unmanned aerial vehicle.

[0049] In the embodiment of the present invention, in the said Step 3,

[0050] The obtained height h2 of the unmanned aerial vehicle is: h2 = ρsinθ

[0051] The obtained horizontal distance h3 is: h3 = ρcosθ

[0052] The obtained abscissa and ordinate (x, y) of any point B are:

[0053] x = x1 - cosθ

[0054] y = y1 - sinθ

[0055] In the embodiment of the present invention, in the said Step 4, the linear equation determined by the suspension points A and C is:

[0056]

[0057] In the embodiment of the present invention, in the said Step 5, the calculation formula of h1 is:

[0058]

[0059] where h1 is the ordinate generated by substituting the abscissa x = x1 - cosθ into the linear equation determined by the suspension points in the xoy coordinate system.

[0060] Embodiment 2

[0061] As Figures 1 to 2As shown in the figure, a method for accurately measuring the sag of a wire by an unmanned aerial vehicle (UAV) based on a coaxial double coordinate system. Here, A is the wire suspension point of the first tower, H1 is the height from the suspension point of the first tower to the tower base, C is the wire suspension point of the second tower, H2 is the height from the suspension point of the second tower to the tower base, B is the sag measurement point on the wire; ρ is the straight-line distance between the sag measurement point on the wire and the UAV, θ is the horizontal angle between the sag measurement point on the wire and the UAV, d is the span between adjacent towers, h4 is the wire sag, h2 is the vertical distance from the sag measurement point on the wire to the UAV, h3 is the horizontal distance from the sag measurement point on the wire to the UAV, h1 is the ordinate generated by substituting x = x1 - cosθ into the straight-line equation determined by the suspension point in the xoy coordinate system, and (x1, y1) is the UAV coordinate in the xoy coordinate system. The specific method is as follows:

[0062] Step 1: Establish a two-dimensional coordinate system plane with two adjacent towers. Take any base and the wire suspension point of one of the two adjacent towers as the origin of the rectangular coordinate system, and establish a coaxial double rectangular coordinate system. Establish the x'o'y' rectangular coordinate system with the original coordinate origin of the wire suspension point, and establish the xoy rectangular coordinate system with the base of this tower as the coordinate origin;

[0063] Step 2: Place the ground base station at the coordinate origin O. The UAV takes off with a mobile base station into the span between adjacent towers. The UAV transmits its own coordinates (x1, y1) in real time. The UAV takes its own position as the coordinate origin and establishes a polar coordinate system. Use lidar to scan the coordinates of any point B on the wire relative to the UAV as (ρ, θ);

[0064] Step 3: According to the polar coordinates of point B, the height and horizontal distance of point B relative to the UAV can be obtained: h2 = ρsinθ, h3 = ρcosθ. The abscissa and ordinate of point B are: x = x1 - cosθ, y = y1 - sinθ;

[0065] Step 4: In the x'o'y' rectangular coordinate system, the ordinate of the suspension point C is (d, H1 - H2). It can be obtained that in the x'o'y' rectangular coordinate system, the straight-line equation determined by the suspension points A and C is

[0066] Step 5: Substitute the abscissa x = x1 - cosθ of point B into the straight-line equation, and it can be obtained

[0067] Step 6: At this time, the sag at any point B on the wire is h4 = h1 + H1 - h2 - y1.

[0068] Embodiment 3

[0069] As Figures 1 to 2 shown, a method for accurately measuring the sag of a wire by an unmanned aerial vehicle (UAV) based on a coaxial double coordinate system, Figure 1It is a schematic diagram of adjacent iron towers and wire suspension. A is the wire suspension point of Tower 1. The height H1 from the suspension point of Tower 1 to the tower base is 45m. C is the wire suspension point of Tower 2. B is the measured sag point on the wire. Figure 2 It is a wire sag measurement model. The straight-line distance ρ1 between the measured sag point on the wire and the UAV is 40m. The horizontal angle θ1 between the measured sag point on the wire and the UAV is 30°. The straight-line distance ρ2 between the suspension point C of Tower 2 and the UAV is 50m. The horizontal angle θ1 between the measured sag point on the wire and the UAV is 60°. The span d between adjacent towers is 300m. h4 is the wire sag. h2 is the vertical distance from the measured sag point on the wire to the UAV. h3 is the horizontal distance from the measured sag point on the wire to the UAV. h1 is the ordinate generated by substituting the abscissa x = x1 - ρ1cosθ1 into the straight-line equation determined by the suspension point in the xoy coordinate system. (x1, y1) is the UAV coordinate in the xoy coordinate system. Specifically, in the implementation case, a coordinate system is established with the base and wire suspension point of Tower 1 as the coordinate origin. The steps are as follows:

[0070] Step 1: Take the base and wire suspension point of Tower 1 as the origin of the right-angle coordinate system, establish a coaxial double right-angle coordinate system. Establish the x'o'y' right-angle coordinate system with the original coordinate origin of the wire suspension point, and establish the xoy right-angle coordinate system with the tower base as the coordinate origin.

[0071] Step 2: Place the ground base station at the coordinate origin O. The UAV carries the mobile base station and takes off into the span between adjacent towers. The UAV real-time transmits its own coordinates as (200, 25). The UAV takes its own position as the coordinate origin and establishes a polar coordinate system. Using lidar to scan, the coordinates of point B on the wire relative to the UAV are (40, 30°), and the coordinates of the suspension point C of Tower 2 relative to the UAV are (50, 60°).

[0072] Step 3: According to the polar coordinates of point B, the height and horizontal distance of point B relative to the UAV can be obtained. h2 = 20. The abscissa and ordinate of point B are x = 180.

[0073] Step 4: In the x'o'y' right-angle coordinate system, the ordinate of the suspension point C is (300, h5). It can be obtained that in the x'o'y' right-angle coordinate system, the straight-line equation determined by the suspension points A and C is h5 = ρ2sinθ2 + y1 - H1, that is, h5 = 23.3, d = 300.

[0074] So:

[0075] Step 5: Substitute the abscissa x = x1 - ρ1cosθ1 of point B into the straight-line equation, and we can get It can be obtained that h1 = 12.84m.

[0076] Step 6: At this time, the sag at any point B on the wire is h4 = h1 + H1 - h2 - y1.

[0077] Substitute h1 = 12.84, H1 = 45, h2 = 20, and y1 = 25. It can be obtained that the sag h4 of the wire is 12.84m.

[0078] Working principle: Use any one of the wire suspension points and the tower base in two adjacent towers as the coordinate origin to establish coaxial double rectangular coordinate systems xoy and x'o'y'. And use the lidar carried by the drone to obtain the coordinates (x1, y1) of the drone and the polar coordinates (ρ, θ) of any point on the wire relative to the drone. Substitute them into the coaxial double rectangular coordinate systems xoy and x'o'y' respectively to obtain the vertical distance from the sag measurement point to the drone and the vertical distance from the sag measurement point to the straight line equation established relative to the wire suspension point, so as to obtain the sag.

[0079] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claims.

[0080] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An accurate method for measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial dual coordinate system, characterized in that: Including the following steps Step 1: Establish a two-dimensional coordinate plane with two adjacent iron towers. Take the base of any one of the two adjacent iron towers and the wire suspension point as the origin of the rectangular coordinate system, and establish coaxial double rectangular coordinate systems x'o'y' and xoy; Among them, the suspension point of Tower 1 is A, and the suspension point of Tower 2 is C; Step 2: Place the ground base station at the coordinate origin O. The unmanned aerial vehicle (UAV) takes off with a mobile base station to within the span of the adjacent iron towers. The UAV transmits its own coordinates (x1, y1) in real time. Taking its own position as the coordinate origin, the UAV establishes a polar coordinate system and obtains the coordinates of any point B on the wire relative to the UAV as (ρ, θ); Step 3: Obtain the height h2 and the horizontal distance h3 of any point B relative to the UAV according to the polar coordinates of any point B, and then obtain the horizontal and vertical coordinates (x, y) of any point B; Among them, h2 is the vertical distance from the measured sag point on the wire to the UAV, and h3 is the horizontal distance from the measured sag point on the wire to the UAV; Step 4: In the x'o'y' rectangular coordinate system, the horizontal and vertical coordinates of the suspension point C are (d, H1 - H2). According to the horizontal and vertical coordinates of the suspension point A and the suspension point C of Tower 1, establish the straight-line equation of the two suspension points A and C; Among them, H1 is the height from the suspension point of Tower 1 to the tower base, H2 is the height from the suspension point of Tower 2 to the tower base, and d is the span of the adjacent iron towers; Step 5: Substitute the abscissa of any point B into the straight-line equation, and the ordinate h1 generated by substituting any point B into the straight-line equation determined by the suspension points in the xoy coordinate system can be obtained; Step 6: At this time, the sag at any point B on the wire is: h4 = h1 + H1 - h2 - y1.

2. The method for accurately measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial dual coordinate system according to claim 1, wherein: In the said Step 1, x'o'y' of the coaxial double rectangular coordinate system is established with the wire suspension point as the coordinate origin, and xoy of the coaxial double rectangular coordinate system is established with the tower base as the coordinate origin.

3. A method for accurately measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial dual coordinate system according to claim 1, characterized in that: In the said Step 2, a lidar is used to scan any point B to determine the coordinates of any point B relative to the UAV.

4. A method for accurately measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial dual coordinate system according to claim 1, characterized in that: In the said Step 3, The obtained height h2 of the UAV is: h2 = ρsinθ The obtained horizontal distance h3 is: h3 = ρcosθ The obtained horizontal and vertical coordinates (x, y) of any point B are: x = x1 - cosθ y = y1 - sinθ.

5. The method for accurately measuring the sag of a wire by an unmanned aerial vehicle based on a coaxial dual coordinate system according to claim 1, wherein: In the said Step 4, the straight-line equation established by the suspension points A and C is:

6. The method for accurately measuring the sag of a conductor by an unmanned aerial vehicle based on a coaxial dual coordinate system according to claim 1, wherein: In the said Step 5, the calculation formula for h1 is: Among them, h1 is the ordinate generated by substituting the abscissa x = x1 - cosθ into the straight-line equation determined by the suspension points in the xoy coordinate system.

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