A transmission line sag measurement method and measurement device

Abstract

The present invention discloses a transmission line sag measurement method and device, comprising the following steps: ① a crawling robot crawls along the transmission line to fit the catenary and draw the shape of the transmission line; ② a first unmanned aerial vehicle flies, and a binocular camera records the coordinates of the crossarm; ③ the coordinates of the crossarm in the WGS-84 coordinate system are obtained; ④ the obtained coordinates are brought into the catenary formula obtained in step ① as the y value to obtain the x value; ⑤ the complete shape of the transmission line is drawn. The first unmanned aerial vehicle obtains the coordinate information that the crawling robot cannot reach through the binocular camera, and combines the coordinate information obtained by the crawling robot to jointly draw a complete and accurate shape of the transmission line. The crawling robot uses the starting point of the movement as the (0, 0) point, and subsequently records the absolute value coordinates relative to the starting point, so that the shape of the drawn transmission line has higher accuracy. The second unmanned aerial vehicle transports the crawling robot to the transmission line, and the crawling robot crawls autonomously along the transmission line.

Description

Technical Field

[0001] The invention belongs to the technical field of measurement methods, and in particular relates to a transmission line sag measurement method and a measurement device. Background Art

[0002] The size of the sag is a key factor in whether the line can operate safely. With the continuous advancement of urbanization, the importance of transmission line construction in the power supply work of enterprises has become increasingly prominent. The transmission line is based on the support of poles and towers to achieve the connection of the line in the air. The part with the largest bend is the sag. There are many reasons for the formation of sag, such as changes in atmospheric temperature, transmission capacity and transmission line stress. Good sag observation and adjustment can meet the seismic resistance requirements, and can coordinate the relationship between each point of the transmission line and carriers such as the ground and water surface, to ensure the safety of line operation and the stability of power supply.

[0003] However, when measuring the sag of power transmission lines, traditional measuring robots such as star measuring rods, levels and measuring rulers are generally used to measure on the ground. When the span of the transmission line is large, it is often necessary to walk back and forth in the measurement section, which is time-consuming and laborious. The measurement of sag generally needs to be determined in conjunction with naked eye observation. Affected by the professional level of the observer, the measurement accuracy is low, and good visibility conditions are required. In the case of poor perspective conditions in foggy winter days, sag measurement cannot be performed, which seriously affects the construction efficiency and project progress. This method is not only easily restricted during observation, but also requires a series of tedious and complex manual conversions after observation to obtain the sag size.

[0004] The Chinese patent document with publication number CN112833764B discloses a sag measurement system, method and device based on Beidou positioning and laser radar. The sag measurement system of the patent includes a measurement module, a travel control module and a main control MCU for being set at the transmission line. The measurement module is used to obtain the sag measurement data and send it to the main control MCU for processing, and the travel control module is used to receive the control of the main control MCU to realize movement at the transmission line.

[0005] The crawling device based on the above measurement system often fits the catenary by uniformly taking coordinate points on the transmission line. However, insulators, tension clamps, shock-absorbing hammers and other power devices are installed at both ends of the transmission line. The crawling device cannot walk on this installation distance of the power devices for measurement, and the fitted catenary is only the sag shape of the two ends removed. Taking the shock-absorbing hammer as an example, in order to prevent resonance, the distance between the shock-absorbing hammers at both ends of the transmission line and the power towers on both sides of the transmission line may not be the same; there are also cases where more than two shock-absorbing hammers are installed at one end of the transmission line; and there are many complex situations where the installation positions of the shock-absorbing hammers at both ends are different due to the suspension tower type and the power iron tower type at both ends of the transmission line. That is, the length removed at both ends of the fitted catenary is often different, and the length and curvature of the fitted catenary extending to both ends cannot be determined. The sag refers to the vertical distance between the lowest point and the line connecting the two ends of the sag. Therefore, the measurement indicators caused have errors, especially the sag shape when the two ends of the transmission line are no longer at the same horizontal height, and the error caused is more obvious. Summary of the invention

[0006] In order to overcome the technical problem that the electrical devices installed at both ends of the transmission line in the prior art prevent the crawling device from taking points at the two ends, resulting in a deviation between the fitted catenary and the actual sag shape, and causing errors in the corresponding measurement indicators; one purpose of the present invention is to provide a transmission line sag measurement method, i.e. a measuring device. In addition to relying on a crawling robot to automatically walk on the transmission line to obtain spatial coordinates, an unmanned aerial vehicle equipped with a binocular camera, an attitude sensor, and an RTK module is used to fly near the two ends of the transmission line to obtain the height values ​​of the transmission line endpoints, thereby accurately fitting the entire catenary.

[0007] In order to achieve the above object, the present invention adopts the following technical solution: a transmission line sag measurement method, comprising the following steps:

[0008] ① The crawling robot crawls along the transmission line and evenly obtains the coordinate points on the transmission line, and fits the catenary y=A*Math.Cosh(x / A)-A according to the obtained coordinate points, and draws the shape of the transmission line (excluding the parts where the power devices are set at both ends of the transmission line);

[0009] ② The first UAV flies near the crossarms at both ends of the transmission line, and the binocular camera takes pictures of the crossarms and records the coordinates of the crossarms. ;

[0010] ③ Convert the longitude and latitude coordinates of the binocular camera into WGS-84 coordinates X, Y, Z;

[0011] ④ The cross arm coordinates in the binocular camera coordinate system Converted into WGS-84 coordinates with the binocular camera as the origin :

[0012]

[0013] in, is the deviation distance between the binocular camera reference point and the positioning point;

[0014] R=

[0015] are the rotation Euler angles in three directions, obtained by the inertial sensor IMU of the first UAV;

[0016] ⑤ The coordinates of the cross arm in the WGS-84 coordinate system are:

[0017] , , ;

[0018] ⑥ The obtained Substitute the y value into the catenary formula obtained in step ① to obtain the x value;

[0019] ⑦ Substituting the coordinates of the two crossarms obtained in step ⑥ into the catenary formula obtained in step ①, and drawing the complete shape of the transmission line (including the parts where the power devices are set at both ends of the transmission line);

[0020] ⑧ Based on the sag shape of the transmission line drawn in step ⑦, obtain the relevant information of the minimum sag, midpoint sag, horizontal span, measured span, and wire length in this measurement.

[0021] The power industry has strict regulations on sag error standards. For example, for lines of 220kV and below, the sag error standard is generally between 3% and 5%. For high-voltage lines of 500KV to 1000KV, the sag error standard is 2% to 3%. The higher the voltage of the transmission line, the stricter the corresponding error standard.

[0022] The coordinate points at both ends of the transmission line are obtained by using a binocular camera, and the coordinate points obtained in the crawling path of the crawling robot are combined to obtain the accurate shape of the transmission line, thereby improving the accuracy of power measurement; compared with crawling robots with obstacle traversal capabilities, it has the characteristics of low cost and high safety.

[0023] The binocular camera relies on the recognition and processing of graphics to calculate data. Therefore, the closer the first drone is to the transmission line, the higher the risk of operation; the farther away from the transmission line, the more complex the background of image acquisition, the thinner the transmission line in the image, and the greater the difficulty of measurement. The cross arms at both ends of the transmission line are large in size, which is convenient for image acquisition and calculation. At the same time, the crawling robot is used to take points in the middle of the transmission line. The combination of the two significantly improves safety, data accuracy, and operational convenience.

[0024] In the above step ①, for the catenary y=A*Math.Cosh(x / A)-A, the transmission lines with different sag shapes correspond to a displacement constant A respectively. The coordinate points uniformly taken out by the crawling robot on the transmission line are simulated by iterative calculation and continuous approximation to find the constant A corresponding to the transmission line in the current formula.

[0025] Furthermore, step ① includes the following steps:

[0026] (1) The crawling robot crawls from one side of the transmission line to the other side, and records the longitude and latitude of the starting point as the reference point (0,0) for calculating the absolute distance coordinates;

[0027] (2) Evenly select points in the crawling path and record the absolute distance coordinates (x, y) of each point relative to the reference point (0, 0);

[0028] ⑶Substitute all recorded absolute distance coordinates (x, y) into the catenary formula y=A*Math.Cosh(x / A)-A in turn, and use iterative calculation to continuously approximate to obtain A;

[0029] (4) Substitute the obtained A into the catenary formula again, substitute the x values ​​of all absolute distance coordinates in sequence, and find the corresponding y values;

[0030] (5) Draw the shape of the transmission line (excluding the parts where power devices are installed at both ends of the transmission line) according to the x value of each absolute distance coordinate and the corresponding y value.

[0031] Specifically, the crossarm coordinates are the connection points between the crossarm and the transmission line.

[0032] A transmission line sag measuring device includes the crawling robot, the crawling robot includes a shell, a clamping part arranged at the lower part of the shell, and at least one straight driving part arranged at the upper part of the shell; an RTK positioning module is arranged on the shell to record the coordinate information of each sampling point on the transmission line.

[0033] Furthermore, it includes a second drone for carrying the crawling robot; a drone docking portion is provided on the upper part of the shell; the drone docking portion includes a T-nut movably connected to the upper end of the shell; a screw is longitudinally slidably connected to the lower end of the second drone; a docking motor for driving the screw to rotate is provided on the second drone; the screw can be optionally extended from the lower end of the second drone.

[0034] Specifically, the drone docking part includes two T-shaped magnets symmetrically arranged on the upper end of the shell and two anti-twist holes symmetrically arranged on the upper end of the shell; the magnetic poles at the upper ends of the two T-shaped magnets are different; the lower end of the second drone is provided with two positioning magnets for magnetically attracting the corresponding T-shaped magnets; the lower end of the second drone is provided with two plugs for inserting into the corresponding anti-twist holes.

[0035] Specifically, a nut pressure plate is provided at the upper end of the shell; a handle connecting plate is provided at the lower end of the nut pressure plate; a movable cavity is provided at the lower end of the nut pressure plate; the T-nut is located in the movable cavity, and the T-nut can slide horizontally or longitudinally in the movable cavity but cannot rotate.

[0036] The two T-shaped magnets provide positioning assistance for the UAV, so that the screw rod is directly opposite to the T-shaped nut, the screw rod rotates and extends downward and enters into the T-shaped nut, and the crawling robot is loaded on the second UAV.

[0037] Furthermore, the clamping part includes two sets of clamping rods rotatably connected to the shell and a clamping motor arranged in the shell for driving the clamping rods to rotate; the ends of the clamping rods are rotatably connected to abutment rollers; the straight driving part includes creeping rollers horizontally rotatably connected to the shell; the abutment rollers and the creeping rollers clamp the power transmission line.

[0038] Specifically, a posture sensor is arranged in the shell; the posture sensor is used to monitor the angle of the crawling robot relative to the horizontal plane; the clamping motor adjusts the clamping force according to the angle provided by the posture sensor.

[0039] That is, the crawling robot can monitor the inclination angle of the power transmission line. The larger the inclination angle, the greater the clamping force; the smaller the inclination angle, the smaller the clamping force; there is a sufficiently large friction between the crawling roller of the crawling robot and the power transmission line, which enables it to have a sufficiently large climbing ability.

[0040] Specifically, the clamping part includes two main rotating rods rotatably connected to the shell, and two fan gears respectively arranged at one end of the corresponding main rotating rods; the fan gears are transmission connected to the clamping motor; and the clamping rods are respectively arranged at both ends of the main rotating rod.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The first drone uses a binocular camera to obtain the coordinate information of the power devices installed at both ends of the transmission line, which the crawling robot cannot reach. Combined with the coordinate information obtained by the crawling robot, a complete and accurate shape of the transmission line is drawn together, which helps to improve the accuracy of the corresponding indicators.

[0043] 2. The crawling robot takes the starting point of the movement as the (0, 0) point, and subsequently records the absolute value coordinates relative to the starting point, which can more conveniently and quickly calculate the relative distances of other collected coordinates, making it easier to fit the line shape and draw curves.

[0044] 3. The second UAV transports the crawling robot to the power line. The crawling robot crawls autonomously along the power line. The T-shaped magnet on the crawling robot provides positioning assistance for the connection between the second UAV and the crawling robot. At the same time, the studs and T-shaped nuts also increase the stability and firmness of the connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The schematic diagram of the binocular camera of the present invention for calculating the cross arm coordinates;

[0046] Figure 2 , Figure 3 It is a schematic structural diagram of the front and back sides of the crawling robot of the present invention;

[0047] Figure 4 It is a structural schematic diagram of the straight driving part of the present invention;

[0048] Figure 5 It is a structural schematic diagram of the clamping part of the present invention;

[0049] Figure 6 It is a structural schematic diagram of the UAV docking part of the present invention;

[0050] Figure 7 It is a schematic cross-sectional structure diagram of the UAV docking part of the present invention.

[0051] In the figure: 1. Shell; 2. Straight drive unit; 21. Crawling roller; 22. Big gear; 23. Crawling motor; 24. Small gear; 25. Cooling fan; 3. Clamping unit; 31. Clamping rod; 32. Main rotating rod; 33. Eccentric rotating rod; 34. Fan gear; 35. Reversing gear; 36. Clamping motor; 37. Motor gear; 38. Abutment roller; 4. UAV docking unit; 41. T-shaped magnet; 42. Handle connecting plate; 43. Nut pressure plate; 44. T-shaped nut; 45. Anti-twist hole; 51. Camera module; 52. Communication module; 53. Main board; 54. Laser ranging module; 55. Battery module. DETAILED DESCRIPTION

[0052] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0053] In the description of the present invention, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating directions and positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and should not be understood as limiting the specific scope of protection of the present invention.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. Therefore, the definition of "first" and "second" features can explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise specified and limited, the terms "setting", "installation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can also be a mechanical connection; it can be directly connected, or it can be connected through an intermediate medium, or the two elements can be internally connected. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] See also Figure 1-Figure 7 A transmission line sag measurement method comprises the following steps:

[0057] ① The crawling robot crawls from one side of the transmission line to the other side, and records the longitude and latitude of the starting point as the reference point (0,0) for calculating the absolute distance coordinates;

[0058] ② Evenly select points in the crawling path and record the absolute distance coordinates (x, y) of each point relative to the reference point (0, 0);

[0059] ③ Substitute all (x, y) in step ② into the catenary formula y=A*Math.Cosh(x / A)-A in turn, and use iterative calculation to continuously approximate to obtain A, where the catenary formula and multiple coordinate points on the transmission line are known, and the scattered points are fitted into the catenary according to Newton's method. This is specifically implemented in Haskell language, which is a prior art content and will not be described in detail.

[0060] ④ Substitute the obtained A into the catenary formula again, and substitute the x values ​​of all the absolute distance coordinates in step ② in turn to find the corresponding y values;

[0061] ⑤ The first UAV flies near the crossarms at both ends of the transmission line, and the binocular camera takes pictures of the crossarms and records the coordinates of the crossarms. ;

[0062] ⑥ Convert the longitude and latitude coordinates of the binocular camera into WGS-84 coordinates X, Y, Z, wherein the binocular camera is provided with a positioning device capable of outputting the longitude and latitude coordinates externally;

[0063] ⑦ The cross arm coordinates (i.e., the connection point between the cross arm and the transmission line) in the binocular camera coordinate system Converted into WGS-84 coordinates with the binocular camera as the origin :

[0064]

[0065] in, is the deviation distance between the binocular camera reference point and the positioning point;

[0066] R=

[0067] are the rotation Euler angles in three directions, obtained by the inertial sensor IMU of the first UAV;

[0068] ⑧ The coordinates of the cross arm in the WGS-84 coordinate system are:

[0069]

[0070] ⑨ The obtained Substitute the y value into the catenary formula obtained in step ③ to obtain the x value;

[0071] ⑩ Draw the complete shape of the transmission line based on the coordinates of the two crossarms obtained in step ⑨ and the coordinates in step ④, and obtain the relevant information of the minimum sag, midpoint sag, horizontal span, measured span, and wire length in this measurement.

[0072] A transmission line sag measuring device includes the crawling robot and a second UAV for carrying the crawling robot; the crawling robot includes a shell 1, a clamping portion 3 arranged at the lower part of the shell 1, two straight driving portions 2 arranged at the upper part of the shell 1, and a UAV docking portion 4 arranged at the upper end of the shell 1.

[0073] The drone docking part 4 includes two T-shaped magnets 41 symmetrically arranged on the upper end of the shell 1, and a T-shaped nut 44 movably connected to the upper end of the shell 1 and located between the two T-shaped magnets 41; the magnetic poles at the upper ends of the two T-shaped magnets 41 are different; the lower end of the second drone is provided with two positioning magnets for magnetically attracting the corresponding T-shaped magnets 41; the lower end of the second drone is longitudinally slidably connected with a screw; the second drone is provided with a docking motor for driving the screw to rotate; the screw can be optionally extended from the lower end of the second drone.

[0074] The upper end of the shell 1 is symmetrically provided with two anti-twist holes 45 ; the lower end of the second UAV is provided with two plugs for inserting into the corresponding anti-twist holes 45 .

[0075] A nut pressing plate 43 is provided at the upper end of the shell 1; a handle connecting plate 42 is provided at the lower end of the nut pressing plate 43; a movable cavity is provided at the lower end of the nut pressing plate 43; the T-nut 44 is located in the movable cavity, and the T-nut 44 can slide horizontally or longitudinally in the movable cavity but cannot rotate.

[0076] The clamping part 3 includes two main rotating rods 32 rotatably connected to the shell 1, two fan gears 34 respectively arranged at one end of the corresponding main rotating rods 32, and a clamping motor 36 arranged in the shell 1; the main rotating rod 32 is arranged along the movement direction of the shell 1; the two ends of the main rotating rod 32 are respectively provided with clamping rods 31; the lower end of the clamping rod 31 is rotatably connected to a coaxially arranged abutment roller 38.

[0077] A motor gear 37 is coaxially arranged on the output shaft of the clamping motor 36; a reversing gear 35 which is rotatably connected to the motor gear 37 is provided in the housing 1; wherein one of the sector gears 34 is transmission connected to the motor gear 37, and the other sector gear 34 is transmission connected to the reversing gear 35.

[0078] An eccentric rotating rod 33 is disposed on the sector gear 34 ; the rotating axis of the eccentric rotating rod 33 is parallel to the rotating axis of the main rotating rod 32 and does not overlap.

[0079] A posture sensor is arranged in the shell 1; the posture sensor is used to monitor the angle of the crawling robot relative to the horizontal plane; the clamping motor 36 adjusts the clamping force according to the angle provided by the posture sensor.

[0080] The straight driving part 2 includes a creeping roller 21 horizontally rotatably connected to the shell 1, a large gear 22 coaxially arranged at one end of the creeping roller 21, a creeping motor 23 arranged in the shell 1, and a small gear 24 arranged on the output shaft of the creeping motor 23; the small gear 24 is transmission-connected to the large gear 22; the abutment roller 38 and the creeping roller 21 clamp the power transmission line; the clamping motor 36 adjusts the clamping force according to the stress feedback of the abutment roller 38; and a cooling fan 25 is arranged at the lower end of the creeping motor 23.

[0081] Camera modules 51 are respectively provided at the front and rear ends of the shell 1; a communication module 52 is provided at the upper end of the shell 1; the shell 1 is an inverted U-shaped structure; a main board 53 is provided at the lower part of the shell 1; laser ranging modules are respectively provided at the front and rear ends of the shell 1; and a battery module 55 is provided at the lower part of the shell 1.

[0082] Transmission line measurements:

[0083] ① The crawling robot is placed on the power line through the second UAV. The crawling robot automatically detects the loading of the power line (a sensor for detecting the loading of the power line is set between the two clamping rods). When the power line is loaded, the clamping part automatically sets the clamping angle and clamping force according to the inclination angle of the power line to keep the power line clamped.

[0084] ② Use the ground computer to control the movement and stop of the crawling robot; the crawling robot is equipped with camera modules and laser ranging modules at the front and back, which can observe the surrounding situation and sense the distance of obstacles in front in real time so as to respond.

[0085] ③ The crawling robot is integrated with the RTK Beidou positioning module. During its movement on the transmission line, it performs carrier phase differential calculation with the RTK ground base station on the ground, collects Beidou observation data at the same time, and forms differential observation values ​​within the system for real-time processing to obtain the positioning coordinate information of the transmission line in real time.

[0086] Endpoint measurement:

[0087] ① The first drone is equipped with an RTK Beidou positioning module, a binocular camera, and an attitude sensor, and controls the drone to fly near the crossarm.

[0088] ② Use the binocular camera for visual positioning to find the endpoint to be positioned (the connection point between the transmission line and the crossarm); because the first UAV has a certain angle when flying and docking, it is equipped with an attitude sensor to obtain angle information; the RTK Beidou positioning module can obtain the height value of the endpoint.

[0089] ③ Given the height of the endpoint and the spatial coordinates of each point on the transmission line segment, the ground computer draws the sag shape of the transmission line after receiving the coordinate information, and accurately obtains the sag data of the transmission line and the adjustment direction and value.

[0090] In view of the shortcomings of the prior art, the present invention improves the convenience, adaptability and accuracy of measurement from five aspects:

[0091] 1. It is small and light, easy to carry and transfer, and can be used on overhead transmission lines without changing the original sag of the transmission lines. It can also be used when the minimum line distance of multiple split transmission lines is 115mm.

[0092] 2. The wheel claw composite mechanism and variable clamping mechanism are designed, and the clamping rod is lengthened to adapt to more transmission line sizes (diameter 15mm-60mm); there is a pair of abutment rollers on each side, and the abutment rollers are equipped with rubber sleeves to protect the clamping claws, increase the contact area, and increase the friction when clamping the transmission line; driving rollers are respectively arranged on both sides of the shell, and the abutment rollers symmetrical on both sides keep the transmission line in the center position of the crawling rollers at all times to ensure the correct posture of the crawling robot; the clamping motor adopts a servo motor with a harmonic reduction structure and is directly driven by 4 gears. Due to the reversibility of the straight drive part, the abutment rollers symmetrical on both sides are elastically clamped, and the straight drive part will not be stuck due to changes in the diameter of the transmission line.

[0093] 3. The servo motor can output different torques by driving different currents. Therefore, when the crawling robot encounters a large slope, the system gives the servo motor a corresponding large current. On a straight road, it uses a small current to drive. Due to the sufficient torque of the servo motor, when encountering a large slope power transmission line, the clamping force of the symmetrical abutment rollers on both sides increases, and the friction of the crawling rollers increases, so the crawling robot has a great climbing ability.

[0094] 4. RTK Beidou navigation positioning technology and binocular camera target positioning technology can obtain all spatial three-dimensional coordinate data of the transmission line (including the crossarm), and through data analysis and calculation, quickly and accurately obtain the transmission line sag data and adjustment direction and value.

[0095] 5. Use drones to carry crawling robots up and down the line. Drones also allow the machines to cross over hardware such as spacers on transmission lines.

[0096] 6. Support static detection of transmission lines and dynamic detection during line laying.

[0097] The above description is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the patent scope of the present invention.

Claims

1. A method for measuring sag of a transmission line, characterized in that: The steps include: ① The crawling robot crawls along the transmission line and evenly obtains the coordinate points on the transmission line. According to the obtained coordinate points, it fits the catenary y=A*Math.Cosh(x / A)-A and draws the shape of the transmission line; ② The first UAV flies near the crossarms at both ends of the transmission line, and the binocular camera takes pictures of the crossarms and records the coordinates of the crossarms. ; ③ Convert the longitude and latitude coordinates of the binocular camera into WGS-84 coordinates X, Y, Z; ④ The cross arm coordinates in the binocular camera coordinate system Converted into WGS-84 coordinates with the binocular camera as the origin : ， in, is the deviation distance between the binocular camera reference point and the positioning point, R= ， are the rotation Euler angles in three directions, obtained by the inertial sensor IMU of the first UAV; ⑤ The coordinates of the cross arm in the WGS-84 coordinate system are: ， ， ； ⑥ The obtained Substitute the y value into the catenary formula obtained in step ① to obtain the x value; ⑦ Substitute the coordinates of the two crossarms obtained in step ⑥ into the catenary formula obtained in step ① to draw the complete shape of the transmission line; ⑧ Based on the sag shape of the transmission line drawn in step ⑦, obtain the relevant information of the minimum sag, midpoint sag, horizontal span, measured span, and wire length in this measurement.

2. The measuring method according to claim 1, characterized in that: Step ① includes the following steps: (1) The crawling robot crawls from one side of the transmission line to the other side, and records the longitude and latitude of the starting point as the reference point (0,0) for calculating the absolute distance coordinates; (2) Evenly select points in the crawling path and record the absolute distance coordinates (x, y) of each point relative to the reference point (0, 0); ⑶ Substitute all recorded absolute distance coordinates (x, y) into the catenary formula y=A*Math.Cosh(x / A)-A in turn, and use iterative calculation to continuously approximate to obtain A; (4) Substitute the obtained A into the catenary formula again, substitute the x values ​​of all absolute distance coordinates in sequence, and find the corresponding y values; ⑸ Draw the shape of the transmission line based on the x value of each absolute distance coordinate and the corresponding y value.

3. The measuring method according to claim 1, characterized in that: The cross arm coordinates are the connection points between the cross arm and the transmission line.

4. A transmission line sag measuring device, applied to the measuring method according to any one of claims 1 to 3, characterized in that: The crawling robot includes a shell, a clamping part arranged at the lower part of the shell, and at least one straight driving part arranged at the upper part of the shell; an RTK positioning module is arranged on the shell to record the coordinate information of each sampling point on the transmission line.

5. The measuring device according to claim 4, characterized in that: It includes a second drone for carrying the crawling robot; a drone docking portion is provided on the upper part of the shell; the drone docking portion includes a T-nut movably connected to the upper end of the shell; a screw is longitudinally slidably connected to the lower end of the second drone; a docking motor for driving the screw to rotate is provided on the second drone; the screw can be selectively extended from the lower end of the second drone.

6. The measuring device according to claim 5, characterized in that: The drone docking part includes two T-shaped magnets symmetrically arranged at the upper end of the shell and two anti-twist holes symmetrically arranged at the upper end of the shell; the magnetic poles at the upper ends of the two T-shaped magnets are different; the lower end of the second drone is provided with two positioning magnets for magnetically attracting the corresponding T-shaped magnets; the lower end of the second drone is provided with two plugs for inserting into the corresponding anti-twist holes.

7. The measuring device according to claim 5, characterized in that: A nut pressing plate is provided at the upper end of the shell; a handle connecting plate is provided at the lower end of the nut pressing plate; a movable cavity is provided at the lower end of the nut pressing plate; the T-nut is located in the movable cavity, and the T-nut can slide horizontally or longitudinally in the movable cavity but cannot rotate.

8. The measuring device according to any one of claims 4 to 7, characterized in that: The clamping part includes two sets of clamping rods rotatably connected to the shell and a clamping motor arranged in the shell for driving the clamping rods to rotate; the ends of each clamping rod are rotatably connected to abutment rollers; the straight driving part includes creeping rollers horizontally rotatably connected to the shell; the abutment rollers and the creeping rollers clamp the power transmission line.

9. The measuring device according to claim 8, characterized in that: A posture sensor is arranged in the shell; the posture sensor is used to monitor the angle of the crawling robot relative to the horizontal plane; the clamping motor adjusts the clamping force according to the angle provided by the posture sensor.

10. The measuring device according to claim 8, characterized in that: The clamping part includes two main rotating rods rotatably connected to the shell, and two fan gears respectively arranged at one end of the corresponding main rotating rods; the fan gears are transmission-connected to the clamping motor; and the clamping rods are respectively arranged at both ends of the main rotating rod.

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