Millimeter wave radar local positioning beam bottom detection device and detection method

Abstract

The invention discloses a millimeter wave radar local positioning beam bottom detection device and method, the device comprises a full-span deflection and damage detection device (1) and a radar local space positioning and automatic operation system (2), the full-span deflection and damage detection device (1) leans against the bottom of a bridge through wheels (101), a camera (105) shoots an image with a fixed zoom parameter, and the radar local space positioning and automatic operation system (2) is connected with the full-span deflection and damage detection device (1). The damage degree can be measured conveniently; the radar local space positioning and automatic operation system (2) provides local space positioning for the aircraft body (201) through front and back millimeter wave radars (202) and four reflection targets (203), a controller (110) presets the operation detection of a beam bottom detection device and the space trajectory of going to a solar charging pile (204), and automatic operation is achieved. According to the invention, the full-span deflection and damage condition of the bridge can be accurately detected, accurate space positioning and storage are carried out on data, and powerful support is provided for bridge health condition evaluation.

Description

Technical Field

[0001] This invention belongs to the field of bridge health monitoring technology, and more specifically, relates to a millimeter-wave radar local positioning beam bottom detection device and detection method. Background Technology

[0002] With the continuous and rapid increase in the number of trunk highway bridges in my country, efficient and accurate inspection of existing bridges is crucial for ensuring public safety, extending service life, and reducing maintenance costs. However, traditional bridge monitoring methods relying on manual inspections or single sensors have significant limitations: the accuracy of manual inspection data depends on experience, and single sensors can only acquire partial data and are susceptible to failure or decreased accuracy due to working hours and harsh environments such as high temperature and humidity. These traditional methods are resource-intensive and can no longer meet the current industry demand for efficient and accurate detection of bridge deflection and damage across the entire span.

[0003] In the prior art, patent document CN108382594B discloses a drone used for detecting defects at the bottom of bridges, including a fuselage, a remote control device, an ultrasonic probe, and a positioning device. The fuselage is equipped with several rotors, and a flight control module and a signal transmission module are located within the fuselage. The remote control device is electrically connected to the signal transmission module of the fuselage. The ultrasonic probe is mounted on the top of the fuselage. At least three positioning devices are mounted around the ultrasonic probe on the fuselage. The positioning devices are adapted to contact the bottom of the bridge after the ultrasonic probe contacts the test piece and to restrict the horizontal degrees of freedom of the fuselage. The rotors are adapted to provide upward thrust to the fuselage while the ultrasonic probe is in contact with the test piece. This invention provides a technical solution that makes the drone's flaw detection results at the bottom of bridges more reliable and stable, and also has the advantages of strong adaptability and a wide range of applicable working conditions. However, due to frequent drone movement causing parameter changes and the camera's inability to maintain parallelism with the structural surface, images become tilted and blurred, and the drone is easily affected by external lighting conditions, resulting in poor recognition performance.

[0004] In the prior art, patent document CN114604334A discloses a wall-climbing robot and method for detecting defects in high bridge piers and beams. It includes a clamp-type main structure with a wall-climbing unit and a detection unit mounted on it. The wall-climbing unit includes an adsorption mechanism and a walking mechanism. The adsorption mechanism provides a stable adsorption force to the bridge pier surface through negative pressure, while the walking mechanism drives the wall-climbing robot to move along the surface of the bridge pier. The detection unit is used to detect the bridge pier surface and the bottom of the beam during the operation of the walking mechanism. This solves the problems of short flight time, susceptibility to wind, and low safety associated with current UAV detection methods, as well as the poor adaptability of articulated wall-climbing robots, which are prone to instability in high-wind conditions on high bridge piers. It can achieve one-time data acquisition, completing the location and description of defects, and is effective in adapting to bridge piers of different sizes. However, it still does not solve the problem that a single sensor can only acquire local data of the bridge, and that working time and environment have a significant impact on the sensor's lifespan. Furthermore, this wall-climbing robot cannot be used for comprehensive detection of various data points on the bottom of bridge beams.

[0005] In summary, the existing technologies have the following shortcomings: (1) Poor positioning accuracy. Traditional aircraft mainly rely on the global navigation satellite system. The positioning accuracy is poor in areas where signals are easily blocked or unstable, such as under bridges. Moreover, the existing technologies are significantly insufficient in terms of accurate positioning of damaged locations, especially in terms of millimeter-level accuracy, making it difficult to meet the requirements for fine-grained assessment and precise maintenance of bridge health status; (2) Unstable image quality. Frequent movement of UAVs, changes in camera attitude, and fluctuations in lighting conditions can all lead to image tilting, blurring, and poor recognition effects, making it difficult to meet the requirements for accurate recognition and positioning; (3) Limited monitoring data. The existing technologies cannot simultaneously solve core issues such as full-span deflection detection, millimeter-level precise positioning, stable and high-quality data acquisition, and highly automated operation. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a millimeter-wave radar local positioning beam bottom detection device and detection method, which can accurately detect the deflection and damage of the entire span of the bridge and accurately locate the damage location.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A millimeter-wave radar local positioning beam bottom detection device, characterized in that it comprises: A full-span deflection and damage detection device for acquiring damage images and calculating actual deflection, and a radar local spatial positioning and automated operation system for automating the operation of a millimeter-wave radar local positioning beam bottom detection device. The full-span deflection and damage detection device includes a drive component for driving and detecting the rotation angle of the wheel and the tilt angle of the full-span deflection and damage detection device during the movement of the full-span deflection and damage detection device at the bottom of the beam, an image acquisition component for acquiring images of damage at the bottom of the beam, and a pressure buffer component for relieving and detecting the pressure generated by the wheel pressing against the bottom of the beam during the measurement process. The radar local spatial positioning and automated operation system includes a main body of an aircraft that carries the full-span deflection and damage detection device and provides it with upward lift, as well as front and rear dual millimeter-wave radars and four reflective targets for precise spatial positioning of the millimeter-wave radar local positioning beam bottom detection device. The full-span deflection and damage detection device is mounted on the main body of the aircraft of the radar local spatial positioning and automated operation system. The two are fixedly connected by bolts to form a complete beam bottom detection structure, which can realize the full-span deflection measurement, damage image acquisition and precise spatial positioning of the bridge.

[0008] Furthermore, the drive assembly of the full-span deflection and damage detection device includes wheels symmetrically arranged at the four corners above the box-shaped light shield, and the wheels are indirectly driven by a control motor through gears and wheel axles; The control motor for driving the wheel to roll smoothly along the bottom of the beam is fixedly installed inside the sunshade on the side near the wheel.

[0009] Furthermore, the drive assembly of the full-span deflection and damage detection device includes a rotary encoder for real-time acquisition of the wheel's rotation angle. The rotary encoder is indirectly connected to the wheel's axle via gears to acquire the wheel's rotation angle.

[0010] Furthermore, the drive assembly of the full-span deflection and damage detection device includes an inclination sensor for monitoring the tilt angle of the device during its movement at the bottom of the beam. The inclination sensor is fixed at the center of the bottom of the full-span deflection and damage detection device, and its measuring axis is parallel to the direction of travel of the full-span deflection and damage detection device, thereby enabling the monitoring of the tilt angle of the full-span deflection and damage detection device.

[0011] Furthermore, the image acquisition component of the full-span deflection and damage detection device includes a camera for acquiring images of beam bottom damage. The camera is fixedly installed in the circular groove at the top of the box-shaped light shield, with the lens pointing vertically upward toward the beam bottom and the lens axis coinciding with the vertical center line of the box, thus acquiring images of beam bottom damage. The light shield is a cubic box shape and is located outside the lens of the camera to block external stray light interference. The ring light strip provides a uniform light source for image acquisition. Together, they provide a stable image acquisition environment for the camera.

[0012] Furthermore, the pressure buffer assembly of the full-span deflection and damage detection device includes springs that are respectively vertically installed at the four corners of the bottom of the box-shaped light shield. The springs are used to ensure that the wheel remains in close contact with the bottom of the beam while the full-span deflection and damage detection device can deflect, which is beneficial for the accurate reading of the measured angle. Four pressure sensors are used to detect the pressure transmitted by the springs. Each sensor is installed below one of the four springs. The bottom of the sensor is attached to the top panel of the aircraft body and fixed with screws. Its signal output terminal is electrically connected to the controller through a wire. It can detect the pressure transmitted by the springs, thereby ensuring that the wheel is always in close contact with the bottom of the beam during monitoring, so that the device can detect more accurately.

[0013] Furthermore, the pressure buffer assembly of the full-span deflection and damage detection device includes a controller that receives data from each component and sends control commands. The controller is fixedly installed in the middle position inside the box-shaped light shield of the full-span deflection and damage detection device. It is electrically connected to the control motor, rotary encoder, tilt sensor, camera, ring light strip, pressure sensor and front and rear dual millimeter-wave radars through wires. It can receive data from each component and send control commands. The controller integrates a wireless communication module, which can realize data transmission with the back-end server.

[0014] Furthermore, the radar local space positioning and automated operation system includes an aircraft body that provides power and a carrier for the autonomous operation of the full-span deflection and damage detection device, and the top panel of the fuselage is fixedly connected to the bottom of the pressure sensor of the full-span deflection and damage detection device by bolts; The front and rear dual millimeter-wave radars are installed on the lower sides of the main body of the aircraft to ensure the stability of the center of gravity of the main body of the aircraft during operation. The four reflective targets are fixedly installed in pairs on the sides of the cap beams or abutments at both ends of a bridge. The center of the two reflective targets on the same side is aligned with the center line of the two outermost supports at the same end of the bridge, which can reflect the electromagnetic waves emitted by the front and rear dual millimeter-wave radars.

[0015] Furthermore, the radar local space positioning and automated operation system includes a solar charging pile for docking and charging the main body of the aircraft. The controller automatically controls the main body of the aircraft to fly towards the solar charging pile and accurately dock with the charging interface according to a preset return trajectory to start charging.

[0016] According to a second aspect of the present invention, a method for local positioning beam bottom detection using millimeter-wave radar is provided, implemented using the aforementioned millimeter-wave radar local positioning beam bottom detection device, comprising: S100. Four reflective targets are installed on the sides of the cap beams or abutments at both ends of the bridge to ensure accurate positioning and firm fixation. Solar charging piles are installed in suitable locations to ensure that the beam bottom detection device can return to charge smoothly after the mission is completed. At the same time, good sunlight conditions are ensured to maintain a sufficient power supply. The beam bottom detection device is transported to the vicinity of the bridge, and its main body is manually operated to rise to the vicinity of the bottom of the bridge so that the wheels of the full span deflection and damage detection device are against the bottom of the beam, completing the initial positioning deployment. The S200, manually operated beam bottom detection device moves under the beam, using front and rear dual millimeter-wave radars and reflective targets to initially collect the spatial coordinates of the beam bottom. The tilt sensor monitors the tilt angle of the beam bottom in real time, the camera simultaneously collects image data of the beam bottom, the light shield and the ring light strip ensure a stable image acquisition environment, the pressure sensor monitors the contact pressure between the wheels and the beam bottom and transmits the data to the controller, the controller receives and stores the initially collected spatial coordinate data; S300. Based on the preliminary collected spatial coordinates of the beam bottom, combined with the bridge design drawings and inspection requirements, the operating spatial trajectory of the beam bottom inspection device is preset in the controller. Through dedicated software or programming, the trajectory is divided into multiple key collection points, specifying the coordinate position, inspection task, and corresponding instructions for each collection point. At the same time, the return trajectory of the beam bottom inspection device to the solar charging pile is preset to ensure that it can accurately return to charging when the task is completed or the battery is low. S400 After completing the preset running trajectory, the manual operation of the beam bottom detection device is resumed. The position is continuously corrected using millimeter-wave radar and reflective targets to ensure that the beam bottom detection device accurately reaches the preset starting point and that the pressure sensor detects that the contact pressure between the wheel and the bottom of the beam is within the preset range of the controller. At this time, the automated working program of the beam bottom detection device is started, and the beam bottom detection device will automatically start working according to the preset running detection space trajectory. The S500 beam bottom detection device operates automatically along a preset trajectory. Driven by a control motor, the wheels move along the beam bottom. A rotary encoder monitors the wheel rotation angle θ in real time and transmits this information to the controller. When the rotation angle increment reaches a threshold θ1, the controller simultaneously records the beam bottom tilt angle θ collected by the tilt sensor. 2i Based on the image data collected by the camera, the incremental value ΔL of the forward distance of the beam bottom detection device at that location is calculated using the principle of triangle geometry measurement. i With deflection increment ΔF i The system adds the current calculated value to the historical accumulated data to obtain the actual forward distance parameter L. i and actual deflection value F i This enables the detection of deflection at various locations along the entire span of the bridge. The S600 and dual millimeter-wave radars continuously interact with the reflective target, updating the spatial coordinates of the beam bottom detection device in real time to ensure the accuracy of the detection position. When the beam bottom detection device approaches the mid-span of the bridge, the millimeter-wave radar and reflective target group on the other side are activated to continue precise positioning and detection. At the same time, the controller continuously matches and stores the collected deflection data, image data and corresponding spatial coordinates, providing basic data for subsequent bridge 3D model building and data fusion. After the S700 beam bottom detection device completes the preset full-span detection task, the controller automatically controls the main body of the aircraft to fly towards the solar charging pile according to the preset return trajectory. After the main body of the aircraft arrives at the solar charging pile, it precisely docks with the charging interface and begins the charging process. At the same time, the beam bottom detection device transmits the stored detection data to the background server for technicians to further analyze and evaluate the health status of the bridge. The detection task ends. During the charging process, the beam bottom detection device remains in standby mode, ready to receive new detection task instructions at any time according to the preset start time.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. The full-span deflection and damage detection device of this invention, in conjunction with dual millimeter-wave radars (front and rear) and four reflective targets, establishes a three-dimensional coordinate system using the bridge support positions. This enables precise positioning of the aircraft body and damaged parts of the bridge, achieving millimeter-level accuracy and ensuring the accuracy of the detection results. The application of high-precision distance measurement and triangulation principles by the millimeter-wave radar allows the aircraft body to accurately determine its position in the complex environment beneath the bridge, overcoming the problem of poor positioning accuracy of traditional aircraft bodies under unstable GNSS signals or obstructed conditions. This provides stable, reliable, and high-precision spatial positioning support for bridge inspection.

[0018] 2. The main body of the aircraft of the present invention is equipped with a full-span deflection and damage detection device. Four springs are installed above the pressure sensor so that the wheels remain in close contact with the bottom of the beam when the full-span deflection and damage detection device deflects. This is beneficial for accurate reading of the measurement angle, and enables rapid and efficient comprehensive inspection of the bottom of the bridge beam. It greatly reduces the time and workload of manual inspection and improves the inspection efficiency.

[0019] 3. The main body of the aircraft of this invention can autonomously fly, inspect, and recharge according to a preset trajectory, requiring minimal assistance from personnel. Through the path planning algorithm preset by the controller and the radar local spatial positioning system, the main body of the aircraft can autonomously complete complex flight tasks, realizing the automation and efficiency of inspection work, and improving the stability and reliability of inspection work.

[0020] 4. This invention integrates multiple functions such as deflection measurement, angle measurement, damage image capture, and millimeter-wave radar positioning. It can simultaneously acquire deflection data at various locations across the entire span of the bridge girder bottom, along with damage information with precise spatial positioning, providing comprehensive and accurate data support for bridge health assessment. The fusion analysis of the data processing system enables real-time monitoring and assessment of bridge health status, timely detection of potential safety hazards, and provides a scientific basis for bridge maintenance and management.

[0021] 5. Throughout its operation, the device of this invention is provided with upward lift by the flight body, keeping it close to the bottom of the bridge beam. It is less affected by natural conditions during image and data acquisition, thus ensuring that the images captured by the camera have fixed scaling parameters. The light shield and the ring light strip jointly provide a stable image acquisition environment for the camera, which facilitates accurate measurement of the degree of damage later. This solves the problem of poor image acquisition quality caused by flight instability in traditional UAV inspection devices during the inspection process.

[0022] 6. The main body of the aircraft of this invention uses a solar charging station to provide charging energy, making full use of renewable energy, reducing dependence on traditional energy sources, and meeting the requirements of green development. The design of the solar charging station not only reduces operating costs but also reduces carbon emissions, making it environmentally friendly and having good social and economic benefits. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the millimeter-wave radar local positioning beam bottom detection device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the overall structure of the full-span deflection and damage detection device according to an embodiment of the present invention; Figure 3 This is a schematic elevation view of the full-span deflection and damage detection device according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the main body of the aircraft according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the working process of the millimeter-wave radar local positioning beam bottom detection device according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a radar local space positioning and automated operation system according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the operating trajectory of the beam bottom detection device according to an embodiment of the present invention; Figure 8 This is a schematic diagram of radar local spatial positioning and automated operation trajectory according to an embodiment of the present invention; Figure 9 is a schematic diagram of the operation of the dual millimeter-wave radar and the reflective target of the millimeter-wave radar local positioning beam bottom detection device according to an embodiment of the present invention. (a) The beam bottom detection device is located at the right support; (b) The beam bottom detection device is operating with dual radars; (c) The beam bottom detection device is switching radars; (d) The beam bottom detection device is operating with a single radar; (e) The beam bottom detection device is located at the left support. Figure 10 This is a schematic diagram illustrating the data collected by the millimeter-wave radar local positioning beam bottom detection device according to an embodiment of the present invention. Figure 11 This is a flowchart illustrating the usage method of the millimeter-wave radar local positioning beam bottom detection device according to an embodiment of the present invention.

[0024] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-Full-span deflection and damage detection device; 101-Wheel; 102-Control motor; 103-Rotary encoder; 104-Tilt sensor; 105-Camera; 106-Sunshade; 107-Annular light strip; 108-Spring; 109-Pressure sensor; 110-Controller; 2-Radar local spatial positioning and automated operation system; 201-Aircraft body; 202-Front and rear dual millimeter-wave radar; 203-Reflective target; 204-Solar charging pile; G-Gear; L-Axle. Detailed Implementation

[0025] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] like Figures 1-8 As shown in the embodiment of the present invention, the millimeter-wave radar local positioning beam bottom detection device includes a full-span deflection and damage detection device 1 and a radar local spatial positioning and automated operation system 2. The full-span deflection and damage detection device 1 is mounted on the aircraft body 201 of the radar local spatial positioning and automated operation system 2. The two are fixedly connected by bolts to form a complete beam bottom detection overall structure, which can realize the full-span deflection measurement, damage image acquisition and precise spatial positioning of the bridge.

[0030] The full-span deflection and damage detection device 1 includes a drive assembly, an image acquisition assembly, a pressure buffer assembly, an inclination sensor 104, and a controller 110. The drive assembly includes wheels 101, a control motor 102, and a rotary encoder 103. The wheels are symmetrically arranged at the four corners above the box-shaped light shield 106 and are indirectly driven by the control motor 102 via gear G and the wheel axle L. The control motor 102 is fixedly installed inside the box-shaped light shield 106 on the side near the wheels 101. The output shaft of the control motor 102 is meshed with the wheel axle L via gear G, enabling the wheels 101 to roll smoothly along the bottom of the beam. The rotary encoder 103 is indirectly connected to the wheel axle L of the wheels 101 via gear G to acquire the rotation angle of the wheels 101 and transmits the measured rotation angle θ to the controller 110. When the controller 110 detects that the increment of the rotation angle θ reaches a threshold θ1, it simultaneously records the tilt angle θ of the bottom of the beam acquired by the inclination sensor 104 at this time. 2i The image data acquired by camera 105, where i represents the number of times the increment reaches θ1 after the start of measurement, is used to calculate the incremental distance ΔL of the millimeter-wave radar local positioning beam bottom detection device corresponding to the i-th angle increment θ1 using the principle of triangle geometry measurement. i With deflection increment ΔF iThe system adds the current calculated value to the historically accumulated actual deflection value and the actual forward distance, thereby obtaining the actual forward distance parameter L based on the rotation angle θ1. i and actual deflection value F i The specific calculation formula is as follows: The high-precision measurement of the tilt sensor 104 ensures the accuracy of deflection calculation, which can accurately reflect the vertical deformation of the bridge in service.

[0031] The millimeter-wave radar local positioning beam bottom detection device is precisely spatially positioned using the full-span deflection and damage detection device 1, the front and rear dual millimeter-wave radars 202, and four reflective targets 203. This allows for precise spatial positioning of the beam bottom locations corresponding to the deflection data and image data. The initial detection position of the full-span deflection and damage detection device 1 is at the bridge support. The horizontal distance y from the beam bottom detection device to the support at this point is obtained using the following formula. i , Two millimeter-wave radars 202 identify two reflective targets 203 arranged on the same side of the bridge support, respectively, and measure the straight-line distance between the millimeter-wave radars 202 and the two reflective targets 203. Taking one of the reflective targets 203 as the origin of the spatial coordinate system, the y-axis of the spatial coordinate system is perpendicular to the mid-span section, the z-axis is perpendicular to the horizontal plane, and the x-axis is perpendicular to the yz plane. Let the distance between the millimeter-wave radar 202 and one of the reflective targets 203 be d1, and the distance with the other reflective target 203 be d2, and the spatial coordinates of the two reflective targets 203 be (x1, y1, z1) and (x2, y2, z2) respectively. Then, the local spatial coordinates (x, y, z) of the millimeter-wave radar 202 can be solved by the following equation: Among them, (x1,y1,z1) and (x2,y2,z2) can be measured to know that h is the height difference in the z-direction between the initial position detected by the reflective target 203 and the millimeter-wave radar local positioning beam bottom detection device. Later, a three-dimensional model of the bridge under inspection can be established, and the spatial coordinates of each position of the beam bottom, the corresponding deflection data and image data can be fused and integrated with the three-dimensional model to facilitate a more intuitive expression of the data.

[0032] The image acquisition component includes a camera 105, a light shield 106, and a ring light strip 107. The camera 105 is fixedly installed in the circular groove at the top of the box-shaped light shield 106, with the lens pointing vertically upwards towards the bottom of the beam. The lens axis coincides with the vertical center line of the box, enabling it to acquire images of damage to the bottom of the beam. The light shield 106 is a cuboid box structure that is narrower at the top and wider at the bottom. It is fastened to the outside of the lens of the camera 105 by a snap-fit. The top of the light shield 106 is kept at a certain distance from the bottom of the beam to block external stray light interference. The ring light strip 107 is an LED light strip that is attached in a ring to the top of the inner wall of the light shield 106. It is coaxially arranged with the lens of the camera 105, and the light direction is vertically upwards, providing a uniform light source for image acquisition. Its power supply is connected to the controller 110 through a wire.

[0033] The pressure buffer assembly includes springs 108 and pressure sensors 109. There are four springs 108, each vertically mounted at one of the four corners of the box-shaped light shield 106. The top of each spring 108 is welded to the bottom of the box, and the bottom is in contact with the top of the pressure sensor 109. There are four pressure sensors 109, each corresponding to one of the four springs 108. The bottom of each sensor is attached to the top panel of the aircraft body 201 and fixed with screws. Their signal output terminals are electrically connected to the controller 110 via wires, enabling them to detect the pressure transmitted by the springs 108.

[0034] The tilt sensor 104 is fixedly installed with screws at the center of the bottom of the upper housing of the full-span deflection and damage detection device 1. Its measuring axis is parallel to the traveling direction of the full-span deflection and damage detection device 1, and it can monitor the tilt angle of the device during the movement of the device under the beam. Its signal output terminal is electrically connected to the controller 110 through a wire. The controller 110 is fixedly installed in the middle of the housing of the full-span deflection and damage detection device 1. It is electrically connected to the control motor 102, rotary encoder 103, tilt sensor 104, camera 105, ring light strip 107, pressure sensor 109 and front and rear dual millimeter-wave radar 202 through wires. It can receive data from each component and send control commands. The controller 110 also integrates a wireless communication module to realize data transmission with the back-end server.

[0035] The radar local spatial positioning and automated operation system 2 includes an aircraft body 201, front and rear dual millimeter-wave radars 202, a reflective target 203, and a solar charging pile 204. The aircraft body 201 is a multi-rotor unmanned aerial vehicle (UAV) structure. The top panel of the fuselage is fixedly connected to the bottom of the pressure sensor 109 of the full-span deflection and damage detection device 1 via bolts, providing upward lift for the device. Two front and rear dual millimeter-wave radars 202 are installed on the lower sides of the aircraft body 201 to ensure the fuselage's center of gravity is centered. Their signal terminals are electrically connected to the controller 110 via wires, receiving reflected signals from the reflective target 203. The reflective target 203 is a triangular pyramidal structure made of metal, with a high-reflectivity coating on its surface. The system consists of four layers, arranged in pairs and fixedly installed on the sides of the cap beams or abutments at both ends of a bridge span. The center of the two reflective targets 203 on the same side is aligned with the center line of the two outermost supports at the same end of the bridge, which can reflect the radar waves emitted by the front and rear dual millimeter-wave radars 202. The solar charging pile 204 includes a solar panel, a charging controller, and a charging interface. The solar panel is installed on a ground column at one end of the bridge via a bracket. The charging interface is fixed to the side of the column and matches the charging interface of the aircraft body 201, enabling automatic docking and charging of the aircraft body 201.

[0036] As shown in Figure 9, the front and rear dual millimeter-wave radars 202 and four reflective targets 203 compensate for the limited beam angle of the millimeter-wave radar 202. When the millimeter-wave radar local positioning beam bottom detection device starts detection from one side of the bridge support, the millimeter-wave radar 202 and reflective target 203 group located at the far end of the support are activated to locate the spatial coordinates of the millimeter-wave radar local positioning beam bottom detection device. When the millimeter-wave radar local positioning beam bottom detection device approaches the mid-span, both sets of millimeter-wave radars 202 and reflective targets 203 are activated. When the spatial coordinates of the two millimeter-wave radars 202 are the same, it indicates that the millimeter-wave radar local positioning beam bottom detection device has reached the mid-span position of the bridge being detected. At this time, the millimeter-wave radar 202 and reflective target 203 group activated in the initial stage are turned off, and the millimeter-wave radar 202 and reflective target 203 group on the other side of the millimeter-wave radar local positioning beam bottom detection device are activated for spatial positioning, that is, the millimeter-wave radar 202 and reflective target 203 group closer to the initial position.

[0037] like Figure 10 As shown, the front and rear dual millimeter-wave radars 202 and four reflective targets 203 can perform spatial positioning of the full-span deflection and damage detection device 1. Whenever the full-span deflection and damage detection device 1 collects deflection data and image data, the controller 110 will receive these two sets of data, match the spatial coordinates (x, y, z) of the corresponding position of the data with the data, and store them.

[0038] like Figure 11 As shown, in another embodiment of the present invention, a method for using a millimeter-wave radar local positioning beam bottom detection device is provided, comprising the following steps: S100. Install four reflective targets 203 on the sides of the cap beams or abutments at both ends of the bridge to ensure accurate positioning and firm fixation. Select a suitable location to install solar charging piles 204 to ensure that the beam bottom detection device can return to charge smoothly after the mission is completed, while ensuring good sunlight conditions to maintain sufficient power supply. Move the beam bottom detection device to the vicinity of the bridge and manually operate its main body 201 to rise to the vicinity of the bottom of the bridge so that the wheels 101 of the full span deflection and damage detection device 1 rest against the bottom of the beam, completing the initial positioning deployment. S200: The manually operated beam bottom detection device moves under the beam. Using the cooperation of the front and rear dual millimeter-wave radars 202 and the reflective target 203, the spatial coordinates of the beam bottom are initially collected. The tilt sensor 104 monitors the tilt angle of the beam bottom in real time. The camera 105 simultaneously collects image data of the beam bottom. The light shield 106 and the ring light strip 107 ensure the stability of the image acquisition environment. The pressure sensor 109 monitors the contact pressure between the wheel 101 and the beam bottom and transmits the data to the controller 110. The controller 110 receives and stores the initially collected spatial coordinate data. S300. Based on the preliminary collected spatial coordinates of the beam bottom, combined with the bridge design drawings and inspection requirements, the operating spatial trajectory of the beam bottom inspection device is preset in the controller 110. Through dedicated software or programming, the trajectory is divided into multiple key collection points, specifying the coordinate position, inspection task, and corresponding instructions for each collection point. At the same time, the return trajectory of the beam bottom inspection device to the solar charging pile 204 is preset to ensure that it can accurately return to charging when the task is completed or the battery is low. S400. After completing the preset running trajectory, the manual operator controls the beam bottom detection device again, continuously using the millimeter-wave radar 202 and the reflective target 203 to perform position correction, ensuring that the beam bottom detection device accurately reaches the preset starting point, and the pressure sensor 109 detects that the contact pressure between the wheel 101 and the beam bottom is within the preset range of the controller 110. At this time, the automated working program of the beam bottom detection device is started, and the beam bottom detection device will automatically start working according to the preset running detection space trajectory. S500, the beam bottom detection device runs automatically along a preset trajectory. The wheel 101 moves along the bottom of the beam under the drive of the control motor 102. The rotary encoder 103 monitors the rotation angle θ of the wheel 101 in real time and transmits it to the controller 110. When the rotation angle increment reaches the threshold θ1, the controller 110 synchronously records the beam bottom tilt angle θ collected by the tilt sensor 104. 2i Using the image data collected by camera 105, the incremental value ΔL of the forward distance of the beam bottom detection device at that location is calculated through the principle of triangle geometry measurement.i With deflection increment ΔF i The system adds the current calculated value to the historical accumulated data to obtain the actual forward distance parameter L. i and actual deflection value F i This enables the detection of deflection at various locations along the entire span of the bridge. The S600 and the front and rear dual millimeter-wave radars 202 continuously interact with the reflective target 203 to update the position coordinates of the beam bottom detection device in space in real time, ensuring the accuracy of the detection position. When the beam bottom detection device approaches the mid-span of the bridge, the millimeter-wave radar 202 and the reflective target 203 group on the other side are activated to continue to perform precise positioning and detection. At the same time, the controller 110 continuously matches and stores the collected deflection data, image data and corresponding spatial coordinates (x, y, z), providing basic data for subsequent bridge 3D model building and data fusion. After the S700 beam bottom detection device completes the preset full-span detection task, the controller 110 automatically controls the main body of the aircraft 201 to fly towards the solar charging pile 204 according to the preset return trajectory. After the main body of the aircraft 201 arrives at the solar charging pile 204, it precisely docks with the charging interface and begins the charging process. At the same time, the beam bottom detection device transmits the stored detection data to the background server for technicians to further analyze and evaluate the health status of the bridge. The detection task ends. During the charging process, the beam bottom detection device always remains in standby mode, according to the preset start time, so as to receive new detection task instructions at any time.

[0039] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A millimeter-wave radar local positioning beam bottom detection device, characterized in that, include: A full-span deflection and damage detection device (1) for acquiring damage images and calculating actual deflection, and a radar local spatial positioning and automated operation system (2) for automating the operation of a millimeter-wave radar local positioning beam bottom detection device. The full-span deflection and damage detection device (1) includes a drive assembly for driving and detecting the rotation angle of the wheel (101) and the tilt angle of the full-span deflection and damage detection device (1) during the movement of the beam bottom, an image acquisition assembly for acquiring images of damage at the beam bottom, and a pressure buffer assembly for relieving and detecting the pressure generated by the wheel (101) pressing against the beam bottom during the measurement process. The radar local spatial positioning and automated operation system (2) includes the aircraft body (201) that carries the full-span deflection and damage detection device (1) and provides it with upward lift, as well as the front and rear dual millimeter-wave radars (202) and four reflective targets (203) for precise spatial positioning of the millimeter-wave radar local positioning beam bottom detection device. The full-span deflection and damage detection device (1) is mounted on the aircraft body (201) of the radar local spatial positioning and automated operation system (2). The two are fixedly connected by bolts to form a complete beam bottom detection overall structure, which can realize the full-span deflection measurement, damage image acquisition and precise spatial positioning of the bridge.

2. The millimeter-wave radar local positioning beam bottom detection device according to claim 1, characterized in that, The drive assembly of the full-span deflection and damage detection device (1) includes wheels (101) symmetrically arranged at the four corners above the box-shaped light shield (106). The wheels (101) are indirectly driven by the control motor (102) through the gear (G) and the wheel axle (L) of the wheel (101). The control motor (102) used to drive the wheel (101) to roll smoothly along the bottom of the beam is fixedly installed inside the light shield (106) on the side close to the wheel (101).

3. The millimeter-wave radar local positioning beam bottom detection device according to claim 2, characterized in that, The drive assembly of the full-span deflection and damage detection device (1) includes a rotary encoder (103) for real-time acquisition of the rotation angle of the wheel (101). The rotary encoder (103) is indirectly connected to the wheel axle (L) of the wheel (101) via a gear (G) to acquire the rotation angle of the wheel (101).

4. The millimeter-wave radar local positioning beam bottom detection device according to claim 3, characterized in that, The drive assembly of the full-span deflection and damage detection device (1) includes an inclination sensor (104) for monitoring the tilt angle of the device during its movement at the bottom of the beam. The inclination sensor (104) is fixed at the bottom center of the full-span deflection and damage detection device (1), and its measuring axis is parallel to the direction of travel of the full-span deflection and damage detection device (1), thereby enabling it to monitor the tilt angle of the full-span deflection and damage detection device (1).

5. A millimeter-wave radar local positioning beam bottom detection device according to any one of claims 1-4, characterized in that, The image acquisition component of the full-span deflection and damage detection device (1) includes a camera (105) for acquiring images of damage at the bottom of the beam. The camera (105) is fixedly installed in the circular groove at the top of the box-shaped light shield (106). The lens is vertically upward toward the bottom of the beam, and the lens axis coincides with the vertical center line of the box body, so as to acquire images of damage at the bottom of the beam. The light shield (106) is a cubic box shape and is located on the outside of the lens of the camera (105) to block external stray light interference. The ring light strip (107) provides a uniform light source for image acquisition. Together, they provide a stable image acquisition environment for the camera (105).

6. A millimeter-wave radar local positioning beam bottom detection device according to any one of claims 1-5, characterized in that, The pressure buffer assembly of the full-span deflection and damage detection device (1) includes springs (108) that are respectively vertically installed at the four corners of the bottom of the box-shaped light shield (106). The springs (108) allow the full-span deflection and damage detection device (1) to deflect while keeping the wheel (101) close to the bottom of the beam, which is beneficial to the accurate reading of the measured angle. Four pressure sensors (109) are used to detect the pressure transmitted by the springs (108). They are installed below the four springs (108) respectively. The bottom of the sensor is attached to the top panel of the aircraft body (201) and fixed with screws. Its signal output end is electrically connected to the controller (110) through a wire. It can detect the pressure transmitted by the springs (108), thereby ensuring that the wheel (101) is always in close contact with the bottom of the beam during monitoring, so that the device can detect the pressure value more accurately.

7. The millimeter-wave radar local positioning beam bottom detection device according to claim 6, characterized in that, The pressure buffer assembly of the full-span deflection and damage detection device (1) includes a controller (110) that receives data from each component and sends control commands. The controller (110) is fixedly installed inside the light shield (106) housing of the full-span deflection and damage detection device (1). It is electrically connected to the control motor (102), rotary encoder (103), tilt sensor (104), camera (105), ring light strip (107), pressure sensor (109), and front and rear dual millimeter-wave radar (202) through wires. It can receive data from each component and send control commands. The controller (110) also integrates a wireless communication module, which can realize data transmission with the back-end server.

8. The millimeter-wave radar local positioning beam bottom detection device according to claim 1, characterized in that, The radar local space positioning and automated operation system (2) includes an aircraft body (201) that provides power and carrier for the autonomous operation of the full span deflection and damage detection device (1), and the top panel of the fuselage is fixedly connected to the bottom of the pressure sensor (109) of the full span deflection and damage detection device (1) by bolts. The front and rear dual millimeter-wave radars (202) are installed on the lower sides of the main body of the aircraft (201) to ensure the stability of the center of gravity of the main body of the aircraft (201) during operation. The four reflective targets (203) are fixedly installed in pairs on the sides of the cap beams or abutments at both ends of the bridge. The target centers of the two reflective targets (203) on the same side are aligned with the center lines of the two outermost supports at the same end of the bridge, which can reflect the electromagnetic waves emitted by the front and rear dual millimeter-wave radars (202).

9. The millimeter-wave radar local positioning beam bottom detection device according to claim 8, characterized in that, The radar local space positioning and automated operation system (2) includes a solar charging pile (204) for docking and charging the main body of the aircraft (201). The controller (110) automatically controls the main body of the aircraft (201) to fly towards the solar charging pile (204) according to the preset return trajectory and accurately dock with the charging interface.

10. A millimeter-wave radar local positioning beam bottom detection device and detection method, characterized in that, A millimeter-wave radar method for localizing beam bottom detection according to any one of claims 1-9 includes: S100, four reflective targets (203) are installed on the cap beams or abutment sides at both ends of the bridge to ensure accurate positioning and firm fixation. Select a suitable location to install solar charging piles (204) to ensure that the beam bottom detection device can return to charge smoothly after the mission is completed, and at the same time ensure that it has good sunlight conditions to maintain sufficient power supply. Move the beam bottom detection device to the vicinity of the bridge and manually operate its aircraft body (201) to rise to the vicinity of the bottom of the bridge so that the wheels (101) of the full span deflection and damage detection device (1) rest on the bottom of the beam to complete the initial position deployment. S200, the manually operated beam bottom detection device moves on the bottom of the beam, and uses the cooperation of front and rear dual millimeter wave radar (202) and reflective target (203) to initially collect the spatial coordinates of the bottom of the beam. The tilt sensor (104) monitors the tilt angle of the bottom of the beam in real time, the camera (105) collects the image data of the bottom of the beam simultaneously, the light shield (106) and the ring light strip (107) ensure the stability of the image acquisition environment, the pressure sensor (109) monitors the contact pressure between the wheel (101) and the bottom of the beam, and transmits the data to the controller (110). The controller (110) receives and stores the initially collected spatial coordinate data. S300. Based on the preliminary collected spatial coordinates of the beam bottom, combined with the bridge design drawings and testing requirements, the operating spatial trajectory of the beam bottom testing device is preset in the controller (110). The trajectory is divided into multiple key collection points by using dedicated software or programming, and the coordinates, detection tasks and corresponding instructions of each collection point are clearly defined. At the same time, the return trajectory of the beam bottom detection device to the solar charging pile (204) is preset to ensure that it can accurately return to charging when the task is completed or the power is low. S400 After completing the preset running trajectory, the manual operator controls the beam bottom detection device again, continuously using millimeter-wave radar (202) and reflective target (203) to perform position correction, ensuring that the beam bottom detection device accurately reaches the preset starting point, and the pressure sensor (109) detects that the contact pressure between the wheel (101) and the beam bottom is within the preset range of the controller (110). At this time, the automated working program of the beam bottom detection device is started, and the beam bottom detection device will automatically start working according to the preset running detection space trajectory. S500, the beam bottom detection device runs automatically along a preset trajectory. The wheel (101) moves along the bottom of the beam under the drive of the control motor (102). The rotary encoder (103) monitors the rotation angle θ of the wheel (101) in real time and transmits it to the controller (110). When the rotation angle increment reaches the threshold θ1, the controller (110) synchronously records the beam bottom tilt angle θ collected by the tilt sensor (104). 2i Based on the image data collected by the camera (105), the incremental value ΔL of the forward distance of the beam bottom detection device at that location is calculated using the principle of triangle geometry measurement. i With deflection increment ΔF i The system adds the current calculated value to the historical accumulated data to obtain the actual forward distance parameter L. i and actual deflection value F i This enables the detection of deflection at various locations along the entire span of the bridge; S600 and the front and rear dual millimeter-wave radars (202) continuously interact with the reflective target (203) to update the position coordinates of the beam bottom detection device in space in real time, ensuring the accuracy of the detection position. When the beam bottom detection device approaches the middle of the bridge span, the millimeter-wave radar (202) and reflective target (203) group on the other side are activated to continue to perform precise positioning and detection. At the same time, the controller (110) continuously matches and stores the collected deflection data, image data and corresponding spatial coordinates, providing basic data for the subsequent establishment of a three-dimensional bridge model and data fusion. After the S700 beam bottom detection device completes the preset full-span detection task, the controller (110) automatically controls the main body of the aircraft (201) to fly towards the solar charging pile (204) according to the preset return trajectory. After the main body of the aircraft (201) arrives at the solar charging pile (204), it precisely docks with the charging interface and begins the charging process. At the same time, the beam bottom detection device transmits the stored detection data to the background server for technicians to further analyze and evaluate the health status of the bridge. The detection task ends. During the charging process, the beam bottom detection device always remains in standby mode and can accept new detection task instructions at any time according to the preset start time.

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