Roadbed slope and pavement flatness detection device and method based on unmanned aerial vehicle

Abstract

The invention relates to the technical field of roadbed slope and road surface flatness detection, in particular to a roadbed slope and road surface flatness detection device and method based on an unmanned aerial vehicle, the unmanned aerial vehicle can be fixed in height and fly parallel to the ideal flatness of a road surface, and the inner side of the bottom end of the unmanned aerial vehicle is rotatably connected with a connecting rod through a rotating ball; the bottom end of the connecting rod is fixedly connected with a connecting cylinder, the inner side of the connecting cylinder is slidably connected with a sliding plate, the bottom end of the sliding plate is fixedly connected with a lifting rod, the bottom end of the lifting rod is fixedly connected with a laser range finder, in the initial state, the sliding plate is located in the middle position in the connecting cylinder, and the vertical height between the laser range finder and the road surface is h, the method is suitable for detecting the flatness of any plane, including a horizontally extending road surface, a road surface in an uphill and downhill form and a roadbed slope with a relatively high gradient, has the advantages of high efficiency, small interference, high precision and the like, and gives full play to the advantages of hovering and fixed-line and fixed-path flight of the unmanned aerial vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of roadbed slope and road surface flatness detection, and in particular to a roadbed slope and road surface flatness detection device and method based on an unmanned aerial vehicle. Background Art

[0002] The flatness of the roadbed refers to the deviation of the longitudinal concavity and convexity of the roadbed surface during the road construction process. It is an important means to control the flatness of the road surface and an important measure to ensure the stability and safety of construction. The flatness of the roadbed is related to the accuracy of the road subgrade construction and the compaction performance of the subgrade, and has an important impact on the overall acceptance quality of the road.

[0003] like Figure 1 As shown in the figure, 1 is the road surface, a1 is the starting point of the road surface 1, and a2 is the end point of the road surface 1. Then the connecting line b from the starting point a1 to the end point a2 is the most ideal flatness of the road surface 1. However, there are more or less convex surfaces 1a and concave surfaces 1b on the road surface 1, which affect the flatness of the road surface 1.

[0004] The flatness detection in the existing technology often uses a vehicle-mounted laser flatness detector to detect the flatness of the roadbed surface. The principle is to use a laser displacement sensor to measure the elevation of the road surface, obtain three-dimensional information of the road surface and the objects along it, and finally obtain the international flatness index. This detection method is greatly affected by road bumps and has the problem of low accuracy. When facing a slope with a high slope, there is also the problem that the vehicle cannot go up and there is a danger.

[0005] In view of the above problems, the present invention proposes a roadbed slope and road surface flatness detection device and method based on drone, which can be applied to the detection of the flatness of any plane, including horizontally extending road surfaces, uphill and downhill road surfaces, and inclined roadbed slopes, and has the advantages of high efficiency, low interference, and high accuracy. Summary of the invention

[0006] The purpose of the present invention is to provide a roadbed slope and road surface flatness detection device and method based on a drone, which can be applied to the detection of the flatness of any plane, including horizontally extending roads, uphill and downhill roads, and inclined roadbed slopes, and has the advantages of high efficiency, low interference, and high accuracy.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a roadbed slope and road surface flatness detection device based on a drone, comprising a drone, the drone can be set at a certain height and fly parallel to the ideal flatness of the road surface, the inner side of the bottom end of the drone is rotatably connected to a connecting rod through a rotating ball, the bottom end of the connecting rod is fixedly connected to a connecting cylinder, the inner side of the connecting cylinder is slidably connected to a slide plate, the bottom end of the slide plate is fixedly connected to a lifting rod, the bottom end of the lifting rod is fixedly connected to a laser rangefinder, in an initial state, the slide plate is in the middle position in the connecting cylinder, and the vertical height between the laser rangefinder and the road surface is h;

[0008] The laser rangefinder can obtain the straight-line distance m between it and the road surface in real time. During the flight, the height position of the laser rangefinder is constantly changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone passes through a concave surface and the height of the laser rangefinder needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone passes through a convex surface and the height of the laser rangefinder needs to be increased.

[0009] A vertically arranged potentiometer is fixedly connected to the inner side of the connecting tube, a slider is embedded in the inner side of one end of the sliding plate, and the slider is slidably arranged on the surface of the potentiometer. The maximum distance difference between the slider and the laser rangefinder moving up and down during the entire flight process is obtained through the potentiometer. The larger the maximum distance difference, the lower the flatness of the road surface.

[0010] Under the above settings, the present invention is suitable for detecting the flatness of any plane, including horizontally extended roads, roads with ups and downslopes, and roadbed slopes with high inclinations. It has the advantages of high efficiency, low interference, high precision, etc., and gives full play to the advantages of drone hovering and fixed-line and fixed-path flight. The present invention realizes the detection of flatness by making the drone fly at a fixed height and parallel to the ideal flatness of the road surface, and obtaining the height difference between the actual convex and concave surfaces of the road surface and the ideal flatness. The main detection principle is that in the initial state, the slide plate is in the middle position in the connecting tube, the vertical height between the laser rangefinder and the road surface is h, and the laser rangefinder can obtain the straight-line distance m between it and the road surface in real time. During the flight, the height position of the laser rangefinder is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone passes through the concave surface and the height of the laser rangefinder needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone passes through the convex surface and the height of the laser rangefinder needs to be increased. The maximum distance difference between the slider and the laser rangefinder moving up and down during the entire flight process is obtained by the potentiometer. The larger the maximum distance difference, the lower the flatness of the road surface.

[0011] As a preferred device for detecting roadbed slope and road surface flatness based on a drone of the present invention, the top of the connecting cylinder is fixedly connected to a motor, the end of the main shaft of the motor is fixedly connected to a screw, the bottom end of the screw is rotatably connected to the inner side of the bottom end of the connecting cylinder, the inner side of the screw is spirally connected to the inner side of a slide board, and the lifting and lowering movement of the slide board is realized by the forward and reverse rotation of the motor.

[0012] As a preferred embodiment of the roadbed slope and road surface flatness detection device based on a drone of the present invention, a vertically arranged limit rod is fixedly connected to the inner side of the connecting cylinder, and the outer side of the limit rod is slidably connected to the inner side of the slide plate.

[0013] As a preferred embodiment of the roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle of the present invention, the center of gravity of the connecting cylinder is located in the middle position of the connecting cylinder.

[0014] As a preferred embodiment of the roadbed slope and road surface flatness detection device based on a drone of the present invention, racks are fixedly connected to both sides of the top of the slide plate, a ratchet is rotatably connected to the middle position of the top of the connecting tube, and two racks are respectively arranged on both sides of the ratchet.

[0015] As a preferred device for detecting the flatness of roadbed slope and road surface based on a drone of the present invention, the outer side of the ratchet is rotatably connected with a pawl via a hinge, a tension spring is arranged on the inner side of one end of the pawl, and the two ends of the tension spring are respectively fixedly connected with one end of the pawl and the outer side of the ratchet; when the skateboard drives the laser rangefinder upward, the rack on the left side clamps the pawl, causing the ratchet to rotate clockwise, and the rack on the right side slides over the pawl, causing the ratchet to rotate clockwise; when the skateboard drives the laser rangefinder downward, the rack on the left side slides over the pawl, and the rack on the right side clamps the pawl, causing the ratchet to rotate clockwise again.

[0016] As a preferred device for detecting roadbed slope and road surface flatness based on a drone of the present invention, the ratchet is coaxially connected with a turn counter, which can accumulate the number of turns of the ratchet. The circumference of the ratchet multiplied by the number of turns can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder during the flight. The larger the cumulative amount, the greater the number of convex and concave surfaces.

[0017] The roadbed slope and road surface flatness detection method based on drone includes the following steps:

[0018] S1: For the first flight, the drone is controlled to take the starting position directly above the starting point of the road surface as the initial position and the ending position directly above the end point of the road surface as the end point for horizontal flight. During the flight of the drone, the vertical distance difference between the starting point and the end point and the horizontal flight distance are obtained by the laser rangefinder installed on the drone to obtain the ideal flatness and slope of the road surface;

[0019] S2: Second flight, the drone is set at a fixed height just above the starting point of the road surface and flies parallel to the ideal flatness. In the initial state, the skateboard is in the middle position of the connecting tube, and the vertical height between the laser rangefinder and the road surface is h. The laser rangefinder can obtain the straight-line distance m between it and the road surface in real time. During the flight, the height position of the laser rangefinder is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone passes through a concave surface and the height of the laser rangefinder needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone passes through a convex surface and the height of the laser rangefinder needs to be increased.

[0020] S3: Detection and analysis: The maximum distance difference between the slider and the laser rangefinder during the entire flight process is obtained through the potentiometer. The larger the maximum distance difference, the lower the flatness of the road surface.

[0021] As a preferred method for detecting the flatness of roadbed slope and road surface based on a drone of the present invention, during the secondary flight process in S2, when the skateboard drives the laser rangefinder upward, the rack on the left side clamps the pawl, causing the ratchet to rotate clockwise, and the rack on the right side will slide over the pawl, causing the ratchet to rotate clockwise. When the skateboard drives the laser rangefinder downward, the rack on the left side will slide over the pawl, and the rack on the right side will clamp the pawl, causing the ratchet to rotate clockwise again. The circle counter can accumulate the number of circles of rotation of the ratchet. The circumference of the ratchet multiplied by the number of circles can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder during the flight. The larger the cumulative amount, the greater the number of convex and concave surfaces on the surface, providing more detection data.

[0022] As a preferred method for detecting the flatness of roadbed slope and road surface based on an unmanned aerial vehicle of the present invention, during the initial flight in S1, the height of the horizontal flight of the unmanned aerial vehicle is greater than the highest position of the road surface.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The roadbed slope and road surface flatness detection device based on drone, in the initial state, the slide plate is in the middle position in the connecting tube, the vertical height between the laser rangefinder and the road surface is h, and the laser rangefinder can obtain the straight-line distance m between it and the road surface in real time. During the flight, the height position of the laser rangefinder is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone passes through a concave surface and the height of the laser rangefinder needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone passes through a convex surface and the height of the laser rangefinder needs to be increased. The maximum distance difference between the slider and the laser rangefinder moving up and down during the entire flight process is obtained through a potentiometer. The larger the maximum distance difference, the lower the flatness of the road surface.

[0025] 2. The UAV-based roadbed slope and road surface flatness detection device is suitable for detecting the flatness of any plane, including horizontally extending roads, uphill and downhill roads, and roadbed slopes with high inclinations. It has the advantages of high efficiency, low interference, and high precision, and gives full play to the advantages of UAV hovering and fixed-line and fixed-path flight.

[0026] 3. The roadbed slope and road surface flatness detection device based on the UAV, during the second flight, when the skateboard drives the laser rangefinder upward, the rack on the left side clamps the pawl, causing the ratchet to rotate clockwise, and the rack on the right side will slide over the pawl, causing the ratchet to rotate clockwise. When the skateboard drives the laser rangefinder downward, the rack on the left side will slide over the pawl, and the rack on the right side will clamp the pawl, causing the ratchet to rotate clockwise again. The circle counter can accumulate the number of circles of the ratchet wheel. The circumference of the ratchet wheel multiplied by the number of circles can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder during the flight. The larger the cumulative amount, the greater the number of convex and concave surfaces on the surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the existing road surface structure and the uneven surface;

[0028] Figure 2 This is a schematic diagram of the first flight of a UAV during the detection process of the present invention;

[0029] Figure 3 A schematic diagram of the secondary flight of the UAV during the detection process of the present invention;

[0030] Figure 4 It is a schematic diagram of the overall appearance structure of the detection device of the present invention;

[0031] Figure 5 It is a schematic diagram of the cross-sectional installation structure in the connecting cylinder of the present invention;

[0032] Figure 6 For the present invention Figure 5 Schematic diagram of the structure at C in FIG.

[0033] Figure 7 For the present invention Figure 5 Schematic diagram of the structure at D in FIG.

[0034] Figure 8 It is a schematic diagram of the structure of the ratchet wheel of the present invention;

[0035] Fig. 9 For the present invention Figure 8 Schematic diagram of the structure at E in .

[0036] In the figure: 1, road surface; 2, drone; 21, connecting rod; 22, connecting tube; 23, circle counter; 24, lifting rod; 25, laser rangefinder; 26, limit rod; 27, skateboard; 28, slider; 29, screw; 210, motor; 211, ratchet; 212, pawl; 213, tension spring; 214, potentiometer; 215, rack; 216, rotating ball. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example 1, please refer to Figure 1-Figure 6 The present invention provides a technical solution: a roadbed slope and road surface flatness detection device based on a drone, comprising a drone 2, the drone 2 can be set at a fixed height and fly parallel to the ideal flatness b of the road surface 1, the inner side of the bottom end of the drone 2 is rotatably connected to a connecting rod 21 through a rotating ball 216, the purpose of rotatably connecting the connecting rod 21 through the rotating ball 216 is to play a role in angle compensation, so as to avoid the tilt of the connecting tube 22 caused by the tilt of the drone 2 during flight, and the connecting tube 22 droops under the action of gravity, and a counterweight block can be added in the connecting tube 22 to increase stability, the bottom end of the connecting rod 21 is fixedly connected to the connecting tube 22, the inner side of the connecting tube 22 is slidably connected to a slide plate 27, the bottom end of the slide plate 27 is fixedly connected to a lifting rod 24, the bottom end of the lifting rod 24 is fixedly connected to a laser rangefinder 25, in the initial state, the slide plate 27 is in the middle position in the connecting tube 22, and the vertical height between the laser rangefinder 25 and the road surface 1 is h;

[0039] The laser rangefinder 25 can obtain the straight-line distance m between it and the road surface 1 in real time. During the flight, the height position of the laser rangefinder 25 is constantly changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone 2 passes through the concave surface 1b, and the height of the laser rangefinder 25 needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone 2 passes through the convex surface 1a, and the height of the laser rangefinder 25 needs to be increased.

[0040] A vertically arranged potentiometer 214 is fixedly connected to the inner side of the connecting tube 22, a slider 28 is embedded in the inner side of one end of the sliding plate 27, and the slider 28 is slidably arranged on the surface of the potentiometer 214. The maximum distance difference between the slider 28 and the laser rangefinder 25 moving up and down during the entire flight process is obtained through the potentiometer 214. The larger the maximum distance difference, the lower the flatness of the road surface.

[0041] Under the above settings, the present invention is suitable for detecting the flatness of any plane, including horizontally extended roads, uphill and downhill roads, and roadbed slopes with high inclinations. It has the advantages of high efficiency, low interference, and high precision, and gives full play to the advantages of drone hovering and fixed-line and fixed-path flight. The present invention detects the flatness by making the drone 2 fly at a fixed height and parallel to the ideal flatness b of the road surface 1, and obtaining the height difference between the actual convex surface 1a and concave surface 1b of the road surface 1 and the ideal flatness b. The main detection principle is that in the initial state, the slide plate 27 is in the middle position in the connecting tube 22, the vertical height between the laser rangefinder 25 and the road surface 1 is h, and the laser rangefinder 25 can detect the flatness in real time. The straight-line distance m between it and the road surface 1 is obtained. If the road surface 1 is flat, then the straight-line distance m and the fixed height h will not produce a large height difference. During the flight, the height position of the laser rangefinder 25 is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone 2 passes through the concave surface 1b, and the height of the laser rangefinder 25 needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone 2 passes through the convex surface 1a, and the height of the laser rangefinder 25 needs to be increased. The maximum distance difference between the slider 28 and the laser rangefinder 25 moving up and down during the entire flight process is obtained through the potentiometer 214. The larger the maximum distance difference, the lower the flatness of the road surface.

[0042] Specifically, the top of the connecting tube 22 is fixedly connected to the motor 210, the end of the main shaft of the motor 210 is fixedly connected to the screw 29, the bottom end of the screw 29 is rotatably connected to the inner side of the bottom end of the connecting tube 22, the inner side of the screw 29 is spirally connected to the inner side of the slide 27, and the lifting and lowering movement of the slide 27 is realized by the forward and reverse rotation of the motor 210.

[0043] Specifically, a vertically arranged limiting rod 26 is fixedly connected to the inner side of the connecting tube 22 , and the outer side of the limiting rod 26 is slidably connected to the inner side of the sliding plate 27 .

[0044] Specifically, the center of gravity of the connecting tube 22 is located in the middle of the connecting tube 22 .

[0045] Example 2: This example is a further improvement of Example 1. Figure 1-Figure 9 Racks 215 are fixedly connected to both sides of the top of the slide plate 27, and a ratchet 211 is rotatably connected to the middle position of the top of the connecting tube 22. Two racks 215 are respectively arranged on both sides of the ratchet 211.

[0046] Specifically, the outer side of the ratchet 211 is rotatably connected to the pawl 212 through a hinge, and a tension spring 213 is arranged on the inner side of one end of the pawl 212. The two ends of the tension spring 213 are respectively fixedly connected to one end of the pawl 212 and the outer side of the ratchet 211. When the slide plate 27 drives the laser rangefinder 25 upward, the rack 215 on the left side clamps the pawl 212, so that the ratchet 211 rotates clockwise, and the rack 215 on the right side slides over the pawl 212, so that the ratchet 211 rotates clockwise. When the slide plate 27 drives the laser rangefinder 25 downward, the rack 215 on the left side slides over the pawl 212, and the rack 215 on the right side clamps the pawl 212, so that the ratchet 211 rotates clockwise again.

[0047] Specifically, the ratchet 211 is coaxially connected to a turn counter 23, which can accumulate the number of turns of the ratchet 211. The circumference of the ratchet 211 multiplied by the number of turns can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder 25 during the flight. The larger the cumulative amount, the greater the number of convex surfaces 1a and concave surfaces 1b on the surface.

[0048] The present invention also discloses a method for detecting the flatness of a roadbed slope and a road surface based on an unmanned aerial vehicle, the steps of which are:

[0049] S1: Initial flight, control the drone 2 to take the starting point 1a of the road surface 1 as the initial position, and take the ending point 1b of the road surface 1 as the end position to perform horizontal flight. During the flight of the drone 2, the vertical distance difference between the starting point 1a and the end point 1b and the horizontal flight distance are obtained by the laser rangefinder 25 installed on the drone 2, and the inclination slope of the ideal flatness b of the road surface 1 is obtained;

[0050] S2: Second flight, the UAV 2 is set at a height just above the starting point 1a of the road surface 1, and flies parallel to the ideal flatness b. In the initial state, the slide plate 27 is in the middle position in the connecting tube 22, and the vertical height between the laser rangefinder 25 and the road surface 1 is h. The laser rangefinder 25 can obtain the straight-line distance m between it and the road surface 1 in real time. During the flight, the height position of the laser rangefinder 25 is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the UAV 2 passes through the concave surface 1b, and the height of the laser rangefinder 25 needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the UAV 2 passes through the convex surface 1a, and the height of the laser rangefinder 25 needs to be increased.

[0051] S3: Detection and analysis: the maximum distance difference between the slider 28 and the laser rangefinder 25 during the entire flight process is obtained through the potentiometer 214. The larger the maximum distance difference is, the lower the flatness of the road surface is.

[0052] Specifically, during the secondary flight in S2, when the skateboard 27 drives the laser rangefinder 25 upward, the rack 215 on the left side clamps the pawl 212, causing the ratchet 211 to rotate clockwise, and the rack 215 on the right side will slide over the pawl 212, causing the ratchet 211 to rotate clockwise. When the skateboard 27 drives the laser rangefinder 25 downward, the rack 215 on the left side will slide over the pawl 212, and the rack 215 on the right side will clamp the pawl 212, causing the ratchet 211 to rotate clockwise again. The circle counter 23 can accumulate the number of circles of the ratchet 211. The circumference of the ratchet 211 multiplied by the number of circles can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder 25 during the flight. The larger the cumulative amount, the greater the number of convex surfaces 1a and concave surfaces 1b on the surface.

[0053] Specifically, during the initial flight in S1 , the height at which the drone 2 flies horizontally is greater than the highest position of the road surface 1 .

[0054] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle, comprising an unmanned aerial vehicle (2), characterized in that: The drone (2) can fly at a fixed altitude and parallel to the ideal flatness (b) of the road surface (1); the inner side of the bottom end of the drone (2) is rotatably connected to a connecting rod (21) through a rotating ball (216); the bottom end of the connecting rod (21) is fixedly connected to a connecting cylinder (22); the inner side of the connecting cylinder (22) is slidably connected to a slide plate (27); the bottom end of the slide plate (27) is fixedly connected to a lifting rod (24); the bottom end of the lifting rod (24) is fixedly connected to a laser rangefinder (25); in an initial state, the slide plate (27) is in a middle position in the connecting cylinder (22); and the vertical height between the laser rangefinder (25) and the road surface (1) is h; The laser rangefinder (25) can obtain the straight-line distance m between it and the road surface (1) in real time. During the flight, the height position of the laser rangefinder (25) is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone (2) passes through a concave surface (1b), and the height of the laser rangefinder (25) needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone (2) passes through a convex surface (1a), and the height of the laser rangefinder (25) needs to be increased. A vertically arranged potentiometer (214) is fixedly connected to the inner side of the connecting tube (22); a slider (28) is embedded in the inner side of one end of the sliding plate (27); the slider (28) is slidably arranged on the surface of the potentiometer (214); and the maximum distance difference between the slider (28) and the laser rangefinder (25) moving up and down during the entire flight process is obtained through the potentiometer (214); the greater the maximum distance difference, the lower the flatness of the road surface.

2. The roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle according to claim 1 is characterized in that: The top end of the connecting tube (22) is fixedly connected to a motor (210), the end of the main shaft of the motor (210) is fixedly connected to a screw rod (29), the bottom end of the screw rod (29) is rotatably connected to the inner side of the bottom end of the connecting tube (22), the inner side of the screw rod (29) is spirally connected to the inner side of the slide plate (27), and the lifting and lowering movement of the slide plate (27) is achieved by the forward and reverse rotation of the motor (210).

3. The roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle according to claim 2 is characterized in that: A vertically arranged limiting rod (26) is fixedly connected to the inner side of the connecting tube (22), and the outer side of the limiting rod (26) is slidably connected to the inner side of the sliding plate (27).

4. The roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle according to claim 3 is characterized in that: The center of gravity of the connecting tube (22) is located in the middle of the connecting tube (22).

5. The device for detecting roadbed slope and road surface flatness based on an unmanned aerial vehicle according to any one of claims 1 to 4, characterized in that: Both sides of the top of the slide plate (27) are fixedly connected with racks (215), and the middle position of the top of the connecting tube (22) is rotatably connected with a ratchet (211), and two racks (215) are respectively arranged on both sides of the ratchet (211).

6. The roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle according to claim 5 is characterized in that: The outer side of the ratchet (211) is rotatably connected to a pawl (212) via a hinge, and a tension spring (213) is arranged on the inner side of one end of the pawl (212), and the two ends of the tension spring (213) are respectively fixedly connected to one end of the pawl (212) and the outer side of the ratchet (211). When the slide plate (27) drives the laser rangefinder (25) upward, the rack (215) on the left side clamps the pawl (212), so that the ratchet (211) rotates clockwise, and the rack (215) on the right side slides over the pawl (212), so that the ratchet (211) rotates clockwise. When the slide plate (27) drives the laser rangefinder (25) downward, the rack (215) on the left side slides over the pawl (212), and the rack (215) on the right side clamps the pawl (212), so that the ratchet (211) rotates clockwise again.

7. The roadbed slope and road surface flatness detection device based on an unmanned aerial vehicle according to claim 6 is characterized in that: The ratchet wheel (211) is coaxially connected to a revolution counter (23), which can accumulate the revolutions of the ratchet wheel (211). The circumference of the ratchet wheel (211) multiplied by the revolutions can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder (25) during flight. The greater the cumulative amount, the greater the number of convex surfaces (1a) and concave surfaces (1b) on the surface.

8. The method for detecting the flatness of roadbed slope and road surface based on drone is characterized in that: The roadbed slope and road surface flatness detection device based on drone as claimed in claim 7 comprises the following steps: S1: initial flight, control the drone (2) to take the starting point (1a) of the road surface (1) as the initial position, and take the ending point (1b) of the road surface (1) as the ending position to perform horizontal flight. During the flight of the drone (2), the vertical distance difference between the starting point (1a) and the ending point (1b) and the horizontal flight distance are obtained by using a laser rangefinder (25) installed on the drone (2), and the inclination slope of the ideal flatness (b) of the road surface (1) is obtained; S2: Second flight, the drone (2) is set at a height directly above the starting point (1a) of the road surface (1), and flies parallel to the ideal flatness (b). In the initial state, the slide plate (27) is in the middle position in the connecting tube (22), the vertical height between the laser rangefinder (25) and the road surface (1) is h, and the laser rangefinder (25) can obtain the straight-line distance m between it and the road surface (1) in real time. During the flight, the height position of the laser rangefinder (25) is continuously changed so that the straight-line distance m is equal to the fixed height h. When the straight-line distance m is greater than the fixed height h, it indicates that the drone (2) passes through the concave surface (1b), and the height of the laser rangefinder (25) needs to be lowered. When the straight-line distance m is less than the fixed height h, it indicates that the drone (2) passes through the convex surface (1a), and the height of the laser rangefinder (25) needs to be increased. S3: Detection and analysis: obtaining the maximum distance difference between the slider (28) and the laser rangefinder (25) moving up and down during the entire flight process through the potentiometer (214). The greater the maximum distance difference, the lower the flatness of the road surface.

9. The method for detecting roadbed slope and road surface flatness based on an unmanned aerial vehicle according to claim 8, characterized in that: During the secondary flight in S2, when the slide plate (27) drives the laser rangefinder (25) upward, the rack (215) on the left side clamps the pawl (212), so that the ratchet (211) rotates clockwise, and the rack (215) on the right side slides over the pawl (212), so that the ratchet (211) rotates clockwise. When the slide plate (27) drives the laser rangefinder (25) downward, the rack (215) on the left side slides over the pawl (212), and the rack (215) on the right side clamps the pawl (212), so that the ratchet (211) rotates clockwise again. The revolution counter (23) can accumulate the revolutions of the ratchet (211), and the circumference of the ratchet (211) multiplied by the revolutions can obtain the cumulative amount of the absolute value of the rise and fall of the laser rangefinder (25) during the flight. The larger the cumulative amount, the greater the number of convex surfaces (1a) and concave surfaces (1b) on the surface.

10. The method for detecting roadbed slope and road surface flatness based on an unmanned aerial vehicle according to claim 8, characterized in that: During the initial flight in S1, the altitude at which the drone (2) flies horizontally is greater than the highest position of the road surface (1).

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