Bridge beam plate bottom surface patrol system based on automatic scanning of unmanned aerial vehicle

Abstract

The invention relates to a bridge beam plate bottom surface patrol system based on unmanned aerial vehicle automatic scanning. The system comprises a mobile vehicle and a multi-rotor unmanned aerial vehicle; the moving vehicle is arranged on a bridge deck, a mechanical arm is arranged on the moving vehicle, the mechanical arm extends to the position below the bottom face of a bridge beam plate along the side edge of a bridge, a hovering platform is arranged on the mechanical arm, and the multi-rotor unmanned aerial vehicle is located on the hovering platform; a laser radar is carried on the multi-rotor unmanned aerial vehicle, and the laser radar is used for scanning the bottom surface of a bridge beam plate to obtain beam bottom point cloud data; a control terminal is arranged on the mobile vehicle, and a flight control module, a generation module and a labeling module are configured in the control terminal; the flight control module is used for planning a flight path and controlling the multi-rotor unmanned aerial vehicle to fly along the flight path, the generation module is used for acquiring beam bottom point cloud data to generate a beam bottom point cloud model, and the labeling module is used for identifying the beam bottom point cloud model and labeling crack positions. The method has the effect of improving the detection efficiency.

Description

Technical Field

[0001] This application relates to the technical field of bridge engineering, and in particular to a bridge beam and slab bottom surface inspection system based on unmanned aerial vehicle (UAV) automated scanning. Background Technology

[0002] With the rapid development of my country's social economy, the construction and maintenance of roads and bridges have made significant progress. However, after bridges are built and opened to traffic, their safety can decline over time due to various factors, affecting the safety of vehicle operation. Therefore, it is necessary to conduct regular inspections and timely repairs of bridges to improve their safety.

[0003] Regarding the aforementioned technologies, the bottom of bridges is difficult to reach during bridge inspection. Traditional inspection methods often employ truss-type or folding-arm bridge inspection vehicles, using hydraulically driven robotic arms to deliver a platform carrying inspection workers to the bottom of the bridge. Workers then manually inspect the bridge bottom using handheld flaw detection equipment. This method has low inspection efficiency and therefore requires improvement. Summary of the Invention

[0004] To improve inspection efficiency, this application provides a bridge beam and slab bottom surface inspection system based on UAV automated scanning.

[0005] The bridge beam and slab bottom surface inspection system based on UAV automated scanning provided in this application adopts the following technical solution: A bridge beam underside inspection system based on drone-based automated scanning includes a mobile vehicle and a multi-rotor drone; The mobile vehicle is set on the bridge deck, and a robotic arm is installed on the mobile vehicle. The robotic arm extends along the side of the bridge to below the bottom surface of the bridge beam. A hovering platform is installed on the robotic arm, and the multi-rotor UAV is located on the hovering platform. The multi-rotor UAV is equipped with a lidar, which is used to scan the bottom surface of the bridge beam to obtain point cloud data of the beam bottom. The mobile vehicle is equipped with a control terminal, which includes a flight control module, a generation module, and an annotation module. The flight control module is used to plan the flight path and control the multi-rotor UAV to fly along the flight path. The generation module is used to acquire the beam bottom point cloud data to generate a beam bottom point cloud model. The annotation module is used to identify the beam bottom point cloud model and annotate the crack locations.

[0006] Preferably, the multi-rotor UAV is equipped with an onboard controller, which is connected to a flight attitude control module, a positioning module and a communication module. The lidar is connected to the onboard controller, and the communication module is used to establish a connection with the control terminal. The flight attitude control module and the positioning module control the flight of the multi-rotor UAV based on the flight path.

[0007] Preferably, the airborne controller is connected to an ultrasonic module, and the airborne controller uses the ultrasonic data from the ultrasonic module to control the safe distance between the multi-rotor UAV and the ground and the bottom surface of the bridge beam through the flight attitude control module.

[0008] Preferably, the control terminal is equipped with a trajectory module, which generates a flight spraying trajectory based on the crack location; The multi-rotor drone is equipped with a spraying assembly for applying waterproof coating. The onboard controller controls the multi-rotor drone to fly and spray based on the flight spraying trajectory through the flight attitude control module and the positioning module.

[0009] Preferably, the spraying assembly includes a mounting base disposed at the bottom of the multi-rotor UAV, a spray chamber disposed within the mounting base, a waterproof coating disposed within the spray chamber, a spray channel communicating with the spray chamber disposed within the mounting base, a spray pipe connected to the spray channel, a spray head disposed at the top of the multi-rotor UAV, the spray pipe connected to the spray head, a spray solenoid valve and a spray pump mounted on the spray pipe, and the spray solenoid valve and the spray pump being controlled by the onboard controller.

[0010] Preferably, the hovering platform is equipped with a paint refill component; The paint refill assembly includes a receiving seat mounted on a hovering platform, a receiving groove on the receiving seat for receiving the mounting base, a paint tank mounted on the hovering platform, a paint pipe connected to the paint tank, a paint pump mounted on the paint pipe, a paint flow channel at the center of the receiving seat, one end of the paint flow channel communicating with the center of the receiving groove, and the paint pipe connected to the other end of the paint flow channel; A supplementary flow channel is provided at the center of the bottom surface of the mounting base. One end of the supplementary flow channel is connected to the spray chamber, and the other end of the supplementary flow channel is connected to the bottom surface of the mounting base. A supplementary one-way valve is provided in the supplementary flow channel.

[0011] Preferably, the bottom of the multi-rotor UAV is provided with a drive base, and the drive base is provided with a lifting part for driving the mounting base to engage with the receiving groove.

[0012] Preferably, the lifting unit includes a lifting electric cylinder, the upper end of the cylinder body of the lifting electric cylinder is connected to the drive seat through a ball joint, and the lower end of the telescopic rod of the lifting electric cylinder is connected to the top center of the mounting seat through a ball joint.

[0013] Preferably, the lower surface of the mounting base is provided with a first hemisphere, the receiving groove is provided with a second hemisphere that matches the first hemisphere, the other end opening of the supplementary flow channel is located at the center of the first hemisphere, and the one end opening of the paint flow channel is located at the center of the second hemisphere.

[0014] Preferably, a metal ring is provided on the outer wall of the mounting base, and an electromagnet for attracting the metal ring is provided on the receiving base.

[0015] In summary, this application includes at least one of the following beneficial technical effects: In this application, the mobile vehicle can travel along the bridge deck. After moving to the corresponding inspection section, the robotic arm extends to the bottom of the bridge beam. A multi-rotor drone, equipped with a lidar, hovers on a platform. The drone plans its flight path and flies over the bottom of the bridge beam. The lidar scans and generates point cloud data of the beam bottom. By analyzing the point cloud data, a point cloud model of the beam bottom is generated, thereby identifying the location of cracks. After the inspection of one inspection section is completed, the mobile vehicle moves to the next inspection section. This method effectively improves the inspection efficiency. Attached Figure Description

[0016] Figure 1 This is a structural schematic diagram of the bottom surface of a bridge beam.

[0017] Figure 2 This is a system block diagram of a bridge beam and slab underpass inspection system that uses drones for automated scanning.

[0018] Figure 3 This is a schematic diagram of a multi-rotor drone hovering and landing.

[0019] Figure 4 This is a structural diagram of a multi-rotor drone.

[0020] Figure 5 This is a schematic diagram of the installation of the receiving seat.

[0021] Explanation of reference numerals in the attached drawings: 1. Mobile vehicle; 2. Multi-rotor UAV; 21. Hovering bracket; 3. Robotic arm; 4. Hovering platform; 5. Spraying assembly; 51. Mounting base; 52. Spray chamber; 53. Spray channel; 54. Spray pipe; 55. Spray bracket; 56. Spray head; 57. Spray solenoid valve; 58. Spray pump; 6. Paint refill assembly; 61. Receiver; 62. Receiver groove; 63. Paint tank; 64. Paint pipe; 65. Paint pump; 66. Paint channel; 7. Refill channel; 8. Refill check valve; 9. Drive base; 10. Lifting cylinder; 11. First hemisphere; 12. Second hemisphere; 13. Metal ring; 14. Electromagnet; 15. Proximity sensor; 16. Detection ring. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0023] A bridge beam and slab underside inspection system based on unmanned aerial vehicle (UAV) automated scanning, referring to Figure 1 and Figure 2 As shown, it includes a mobile vehicle 1 and a multi-rotor drone 2. The mobile vehicle 1 is set on the bridge deck. The mobile vehicle 1 can be a flatbed gasoline vehicle. The mobile vehicle 1 can move on the bridge deck and can park at the location to be detected.

[0024] The mobile vehicle 1 is equipped with a robotic arm 3, which extends along the side of the bridge to below the bottom surface of the bridge beam. The robotic arm 3 is equipped with a suspended platform 4. The robotic arm 3 is a hydraulically driven telescopic arm, which can be raised and lowered at different heights. The suspended platform 4 is always in a horizontal state. By raising and lowering the robotic arm 3 at different heights, the suspended platform 4 can be raised and lowered from the bridge deck to below the bottom surface of the bridge beam.

[0025] The multi-rotor drone 2 is equipped with a hovering bracket 21. The multi-rotor drone 2 is located on the hovering platform 4 via the hovering bracket 21. When the hovering platform 4 is raised and lowered to below the bottom surface of the bridge beam by the robotic arm 3, the multi-rotor drone 2 can be raised and lowered synchronously on the hovering platform 4. Alternatively, after the hovering platform 4 has descended to its position, the multi-rotor drone 2 can fly and land on the hovering platform 4.

[0026] The mobile vehicle 1 is equipped with a control terminal, which can be a server or a computer. The control terminal has a communication unit and is used to establish a connection with the multi-rotor drone 2. The control terminal can plan flight paths to control the multi-rotor drone 2 to fly along those paths. The mobile vehicle 1 is equipped with a power supply to power the control terminal.

[0027] The multi-rotor drone 2 is equipped with a lidar. In one embodiment, the bottom of the multi-rotor drone 2 is provided with a mounting platform, and the lidar is mounted on the mounting platform. In another embodiment, the lidar can also be directly mounted on the fuselage of the multi-rotor drone 2.

[0028] As the multi-rotor UAV 2 flies along the bottom surface of the bridge beam, lidar is used to scan the bottom surface of the bridge beam to obtain point cloud data of the beam bottom.

[0029] The control terminal is equipped with a flight control module, a generation module, and a labeling module. The flight control module is used to plan the flight path. In the flight path planning, a coordinate system is established in advance, with the edge of the bridge beam bottom as the origin. The flight path established in the coordinate system is the subsequent flight path of the multi-rotor UAV 2. In one embodiment, the flight path adopts a zigzag flight path. The control terminal sends the flight path to the multi-rotor UAV 2, and then controls the multi-rotor UAV 2 to fly along the flight path to scan the bottom surface of the bridge beam with lidar.

[0030] The generation module is used to acquire beam bottom point cloud data to generate beam bottom point cloud model. The beam bottom point cloud data is generated by LiDAR scanning the bottom of the bridge beam and sent to the control terminal via multi-rotor UAV 2. The generation module parses the beam bottom point cloud data and then generates the beam bottom point cloud model.

[0031] The annotation module is used to identify the point cloud model of the bridge bottom and mark the location of cracks. After identifying the crack location, the annotation module can also identify the crack width and length based on the point cloud model of the bridge bottom. Thus, staff can complete the crack detection of the bridge bottom of one inspection section. After completing the inspection of one inspection section, the mobile vehicle 1 moves to the next inspection section and repeats the above steps, thereby completing the crack detection of the entire bridge bottom surface. This eliminates the need for a platform carrying inspection workers to the bridge bottom, where workers can manually inspect the bridge bottom using handheld flaw detection equipment, effectively improving inspection efficiency.

[0032] The following describes the specific components of the multi-rotor UAV 2.

[0033] Reference Figure 2 As shown, the multi-rotor UAV 2 is equipped with an onboard controller, which is connected to a flight attitude control module, a positioning module, and a communication module. The onboard controller, flight attitude controller, positioning module, and communication module are located inside the multi-rotor UAV 2.

[0034] The lidar is connected to the airborne controller, and the communication module is used to establish a connection with the control terminal to realize the data information transmission between the multi-rotor UAV 2 and the control terminal.

[0035] The positioning module can use a Beidou + GPS dual-mode antenna, which can improve the positioning accuracy to the centimeter level (1-2cm).

[0036] The flight attitude control module and the positioning module control the flight of the multi-rotor UAV 2 based on the flight path. The flight path is received by the communication module. After receiving the flight path, the airborne controller analyzes the flight path and then controls the flight attitude control module to control the multi-rotor UAV 2 to adjust the flight direction and flight speed. The flight attitude control module, combined with the positioning module, controls the multi-rotor UAV 2 to fly along the flight path.

[0037] It is worth noting that an ultrasonic module is connected to the airborne controller. The ultrasonic module is installed on the fuselage of the UAV. Based on the ultrasonic data from the ultrasonic module, the airborne controller controls the safe distance between the multi-rotor UAV 2 and the ground and the bottom surface of the bridge beam through the flight attitude control module, thereby achieving flight safety of the multi-rotor UAV 2.

[0038] In this application, after the control terminal identifies the location, width, and length of the crack through the point cloud model at the bottom of the beam, it can use a multi-rotor UAV 2 to spray waterproof coating on the crack for repair.

[0039] Specifically, the control terminal is equipped with a trajectory module, which generates a flight spraying trajectory based on the crack location. The flight spraying trajectory covers the crack location and extends 20cm beyond the crack location.

[0040] Reference Figure 3 , Figure 4 and Figure 5 As shown, the multi-rotor drone 2 is equipped with a spraying component 5 for spraying waterproof coating. The onboard controller controls the multi-rotor drone 2 to fly and spray based on the flight spraying trajectory through the flight attitude control module and the positioning module. In the flight spraying trajectory, the multi-rotor drone 2 flies back and forth at the crack location. It is worth noting that the spraying range of the spraying component 5 can fully cover the width of the crack.

[0041] The spraying assembly 5 includes a mounting base 51 disposed at the bottom of the multi-rotor UAV 2. The mounting base 51 is provided with a spray chamber 52, which is filled with waterproof coating. The mounting base 51 is provided with a spray channel 53 that communicates with the spray chamber 52. A spray pipe 54 is connected to the spray channel 53. One end of the spray channel 53 is connected to the bottom of the spray chamber 52, and the other end of the spray channel 53 is connected to the outer surface of the mounting base 51. The spray pipe 54 is disposed outside the mounting base 51, and one end of the spray pipe 54 is connected to the mounting base 51 via a quick connector and communicates with the spray channel 53.

[0042] A spray bracket 55 is provided on the top of the multi-rotor UAV 2. A spray head 56 is provided on the spray bracket 55. A spray pipe 54 extends along the wiring of the multi-rotor UAV 2 and is connected to the spray head 56. A spray solenoid valve 57 and a spray pump 58 are installed on the spray pipe 54. The spray pump 58 and the spray solenoid valve 57 are located on the body of the multi-rotor UAV 2, or the spray pump 58 and the spray solenoid valve 57 are located on the mounting base 51. The spray solenoid valve 57 and the spray pump 58 are controlled by the airborne controller to open and close.

[0043] A paint refill assembly 6 is provided on the hovering platform 4. The paint refill assembly 6 includes a receiving seat 61 provided on the hovering platform 4, a receiving groove 62 provided on the receiving seat 61, the receiving groove 62 is used to receive the mounting seat 51, a paint tank 63 is provided on the hovering platform 4, the paint tank 63 is filled with waterproof paint, a paint pipe 64 is connected to the paint tank 63, a paint pump 65 is installed on the paint pipe 64, a paint flow channel 66 is provided at the center of the receiving seat 61, one end of the paint flow channel 66 is connected to the center of the receiving groove 62, and the paint pipe 64 passes through the hovering platform 4 and is connected to the other end of the paint flow channel 66.

[0044] The mounting base 51 has a supplementary flow channel 7 at the center of its bottom surface. One end of the supplementary flow channel 7 is connected to the spray chamber 52, and the other end of the supplementary flow channel 7 is connected to the bottom surface of the mounting base 51. A supplementary one-way valve 8 is installed in the supplementary flow channel 7.

[0045] To ensure a smoother connection between the mounting base 51 and the receiving groove 62 of the receiving seat 61, a drive base 9 is provided at the bottom of the multi-rotor UAV 2. The drive base 9 has a lifting mechanism for driving the mounting base 51 into the receiving seat 61. The lifting mechanism includes a lifting electric cylinder 10. The upper end of the cylinder body of the lifting electric cylinder 10 is connected to the drive base 9 via a ball joint, and the lower end of the telescopic rod of the lifting electric cylinder 10 is connected to the top center of the mounting base 51 via a ball joint.

[0046] It is worth noting that the lower surface of the mounting base 51 is provided with a first hemisphere 11, the receiving groove 62 is provided with a second hemisphere 12 that matches the first hemisphere 11, the other end opening of the supplementary flow channel 7 is located at the center of the first hemisphere 11, and one end opening of the paint flow channel 66 is located at the center of the second hemisphere 12.

[0047] A metal ring 13 is provided on the outer wall of the mounting base 51, and an electromagnet 14 for attracting the metal ring 13 is provided on the receiving base 61.

[0048] Therefore, when the multi-rotor drone 2 receives the flight spraying trajectory, the multi-rotor drone 2 will fly to the crack location. When the multi-rotor drone 2 hovers at the starting position of the flight spraying trajectory, the spray head 56 will be aligned with the starting point of the crack location, and the airborne controller will control the spray solenoid valve 57 and the spray pump 58 to open.

[0049] The multi-rotor drone 2 flies along the flight spraying trajectory. The waterproof coating is atomized and sprayed from the spray head 56 onto the crack, completing the spraying repair of the crack with waterproof coating.

[0050] After the multi-rotor UAV 2 completes one application of waterproof coating, the waterproof coating in the spray chamber 52 needs to be replenished.

[0051] The control terminal sends instructions to the multi-rotor drone 2, which hovers and lands on the hovering platform 4. The instructions sent by the control terminal contain the position coordinates of the hovering platform 4, so that the multi-rotor drone 2 can accurately land on the hovering platform 4 based on the positioning module, ultrasonic module and flight attitude control module. The hovering bracket 21 supports the multi-rotor drone 2.

[0052] At this time, after the ultrasonic module detects that the multi-rotor drone 2 has hovered and landed on the hovering platform 4, the multi-rotor drone 2 will control the lifting unit to move. The lifting cylinder 10 drives the mounting base 51 to move down. Since the cylinder ball head of the lifting cylinder 10 is connected to the drive seat 9 and the telescopic rod ball head of the lifting cylinder 10 is connected to the mounting base 51, even if there is a certain offset between the mounting base 51 and the receiving groove 62, the lifting cylinder 10 and the mounting base 51 can swing around in a circumferential manner. The mounting base 51 can gradually enter the receiving groove 62 by relying on the first hemisphere 11 and the second hemisphere 12 until the mounting base 51 is completely pressed against the receiving groove 62. At this time, the supplementary flow channel 7 in the mounting base 51 will merge and communicate with the paint flow channel 66 in the receiving groove 62.

[0053] A proximity sensor 15 is provided in the receiving seat 61, and a detection ring 16 is provided in the mounting seat 51. After the mounting seat 51 is driven and pressed into the receiving groove 62 by the lifting electric cylinder 10, the proximity sensor 15 detects the position of the detection ring 16, and the control terminal controls the electromagnet 14 to attract the metal ring 13 of the mounting seat 51.

[0054] The control terminal will control the paint pump 65 to drive, thereby replenishing the waterproof paint in the paint tank 63 to the spray chamber 52 of the mounting base 51, so as to facilitate the next spraying of waterproof paint on the cracks at the bottom of the bridge beam by the multi-rotor UAV 2.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A bridge beam and slab underside inspection system based on unmanned aerial vehicle (UAV) automated scanning, characterized in that, Including mobile vehicles (1) and multi-rotor drones (2); The mobile vehicle (1) is set on the bridge deck. The mobile vehicle (1) is equipped with a robotic arm (3). The robotic arm (3) extends along the side of the bridge to the bottom of the bridge beam. The robotic arm (3) is equipped with a hovering platform (4). The multi-rotor UAV (2) is located on the hovering platform (4). The multi-rotor UAV (2) is equipped with a lidar, which is used to scan the bottom surface of the bridge beam to obtain point cloud data of the beam bottom; The mobile vehicle (1) is equipped with a control terminal, which contains a flight control module, a generation module and a labeling module. The flight control module is used to plan the flight path and control the multi-rotor UAV (2) to fly along the flight path. The generation module is used to acquire the beam bottom point cloud data to generate the beam bottom point cloud model. The labeling module is used to identify the beam bottom point cloud model and label the crack location.

2. The bridge beam and slab underside inspection system based on UAV automated scanning according to claim 1, characterized in that: The multi-rotor UAV (2) is equipped with an onboard controller. The onboard controller is connected to a flight attitude control module, a positioning module and a communication module. The lidar is connected to the onboard controller. The communication module is used to establish a connection with the control terminal. The flight attitude control module and the positioning module control the flight of the multi-rotor UAV (2) based on the flight path.

3. The bridge beam and slab underside inspection system based on UAV automated scanning according to claim 2, characterized in that: An ultrasonic module is connected to the airborne controller. Based on the ultrasonic data from the ultrasonic module, the airborne controller controls the safe distance between the multi-rotor UAV (2) and the ground and the bottom surface of the bridge beam through the flight attitude control module.

4. The bridge beam and slab underside inspection system based on UAV automated scanning according to claim 1, characterized in that: The control terminal is equipped with a trajectory module, which generates a flight spraying trajectory based on the crack location. The multi-rotor drone (2) is equipped with a spraying assembly (5) for spraying waterproof coating. The airborne controller controls the multi-rotor drone (2) to fly and spray based on the flight spraying trajectory through the flight attitude control module and the positioning module.

5. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 4, characterized in that: The spraying assembly (5) includes a mounting base (51) disposed at the bottom of the multi-rotor UAV (2), a spray chamber (52) disposed in the mounting base (51), a waterproof coating disposed in the spray chamber (52), a spray channel (53) disposed in the mounting base (51) communicating with the spray chamber (52), a spray pipe (54) connected to the spray channel (53), a spray head (56) disposed at the top of the multi-rotor UAV (2), the spray pipe (54) connected to the spray head (56), a spray solenoid valve (57) and a spray pump (58) mounted on the spray pipe (54), and the spray solenoid valve (57) and the spray pump (58) being controlled by the airborne controller.

6. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 5, characterized in that: The hovering platform (4) is equipped with a paint replenishment component (6); The paint replenishment component (6) includes a receiving seat (61) disposed on a hovering platform (4), a receiving groove (62) disposed on the receiving seat (61) for receiving the mounting base (51), a paint tank (63) disposed on the hovering platform (4), a paint pipe (64) connected to the paint tank (63), a paint pump (65) installed on the paint pipe (64), a paint flow channel (66) disposed at the center of the receiving seat (61), one end of the paint flow channel (66) communicating with the center of the receiving groove (62), and the paint pipe (64) connected to the other end of the paint flow channel (66). A supplementary flow channel (7) is provided at the center of the bottom surface of the mounting base (51). One end of the supplementary flow channel (7) is connected to the spray chamber (52), and the other end of the supplementary flow channel (7) is connected to the bottom surface of the mounting base (51). A supplementary one-way valve (8) is provided in the supplementary flow channel (7).

7. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 6, characterized in that: The bottom of the multi-rotor UAV (2) is provided with a drive seat (9), and the drive seat (9) is provided with a lifting part for driving the mounting seat (51) to fit into the receiving groove (62).

8. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 7, characterized in that: The lifting unit includes a lifting electric cylinder (10), the upper end of the cylinder body of the lifting electric cylinder (10) is connected to the drive seat (9) through a ball joint, and the lower end of the telescopic rod of the lifting electric cylinder (10) is connected to the top center of the mounting seat (51) through a ball joint.

9. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 7, characterized in that: The lower surface of the mounting base (51) is provided with a first hemisphere (11), the receiving groove (62) is provided with a second hemisphere (12) that matches the first hemisphere (11), the other end opening of the supplementary flow channel (7) is located at the center of the first hemisphere (11), and one end opening of the paint flow channel (66) is located at the center of the second hemisphere (12).

10. A bridge beam and slab underside inspection system based on UAV automated scanning according to claim 7, characterized in that: A metal ring (13) is provided on the outer wall of the mounting base (51), and an electromagnet (14) for attracting the metal ring (13) is provided on the receiving base (61).

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